Correlated electron pseudopotentials for 3d-transition metals

International Nuclear Information System (INIS)

Trail, J. R.; Needs, R. J.

2015-01-01

A recently published correlated electron pseudopotentials (CEPPs) method has been adapted for application to the 3d-transition metals, and to include relativistic effects. New CEPPs are reported for the atoms Sc − Fe, constructed from atomic quantum chemical calculations that include an accurate description of correlated electrons. Dissociation energies, molecular geometries, and zero-point vibrational energies of small molecules are compared with all electron results, with all quantities evaluated using coupled cluster singles doubles and triples calculations. The CEPPs give better results in the correlated-electron calculations than Hartree-Fock-based pseudopotentials available in the literature

3D structure of individual nanocrystals in solution by electron microscopy

Science.gov (United States)

Park, Jungwon; Elmlund, Hans; Ercius, Peter; Yuk, Jong Min; Limmer, David T.; Chen, Qian; Kim, Kwanpyo; Han, Sang Hoon; Weitz, David A.; Zettl, A.; Alivisatos, A. Paul

2015-07-01

Knowledge about the synthesis, growth mechanisms, and physical properties of colloidal nanoparticles has been limited by technical impediments. We introduce a method for determining three-dimensional (3D) structures of individual nanoparticles in solution. We combine a graphene liquid cell, high-resolution transmission electron microscopy, a direct electron detector, and an algorithm for single-particle 3D reconstruction originally developed for analysis of biological molecules. This method yielded two 3D structures of individual platinum nanocrystals at near-atomic resolution. Because our method derives the 3D structure from images of individual nanoparticles rotating freely in solution, it enables the analysis of heterogeneous populations of potentially unordered nanoparticles that are synthesized in solution, thereby providing a means to understand the structure and stability of defects at the nanoscale.

Navigating 3D electron microscopy maps with EM-SURFER.

Science.gov (United States)

Esquivel-Rodríguez, Juan; Xiong, Yi; Han, Xusi; Guang, Shuomeng; Christoffer, Charles; Kihara, Daisuke

2015-05-30

The Electron Microscopy DataBank (EMDB) is growing rapidly, accumulating biological structural data obtained mainly by electron microscopy and tomography, which are emerging techniques for determining large biomolecular complex and subcellular structures. Together with the Protein Data Bank (PDB), EMDB is becoming a fundamental resource of the tertiary structures of biological macromolecules. To take full advantage of this indispensable resource, the ability to search the database by structural similarity is essential. However, unlike high-resolution structures stored in PDB, methods for comparing low-resolution electron microscopy (EM) density maps in EMDB are not well established. We developed a computational method for efficiently searching low-resolution EM maps. The method uses a compact fingerprint representation of EM maps based on the 3D Zernike descriptor, which is derived from a mathematical series expansion for EM maps that are considered as 3D functions. The method is implemented in a web server named EM-SURFER, which allows users to search against the entire EMDB in real-time. EM-SURFER compares the global shapes of EM maps. Examples of search results from different types of query structures are discussed. We developed EM-SURFER, which retrieves structurally relevant matches for query EM maps from EMDB within seconds. The unique capability of EM-SURFER to detect 3D shape similarity of low-resolution EM maps should prove invaluable in structural biology.

3D structure of eukaryotic flagella/cilia by cryo-electron tomography.

Science.gov (United States)

Ishikawa, Takashi

2013-01-01

Flagella/cilia are motile organelles with more than 400 proteins. To understand the mechanism of such complex systems, we need methods to describe molecular arrange-ments and conformations three-dimensionally in vivo. Cryo-electron tomography enabled us such a 3D structural analysis. Our group has been working on 3D structure of flagella/cilia using this method and revealed highly ordered and beautifully organized molecular arrangement. 3D structure gave us insights into the mechanism to gener-ate bending motion with well defined waveforms. In this review, I summarize our recent structural studies on fla-gella/cilia by cryo-electron tomography, mainly focusing on dynein microtubule-based ATPase motor proteins and the radial spoke, a regulatory protein complex.

Transfer function restoration in 3D electron microscopy via iterative data refinement

International Nuclear Information System (INIS)

Sorzano, C O S; Marabini, R; Herman, G T; Censor, Y; Carazo, J M

2004-01-01

Three-dimensional electron microscopy (3D-EM) is a powerful tool for visualizing complex biological systems. As with any other imaging device, the electron microscope introduces a transfer function (called in this field the contrast transfer function, CTF) into the image acquisition process that modulates the various frequencies of the signal. Thus, the 3D reconstructions performed with these CTF-affected projections are also affected by an implicit 3D transfer function. For high-resolution electron microscopy, the effect of the CTF is quite dramatic and limits severely the achievable resolution. In this work we make use of the iterative data refinement (IDR) technique to ameliorate the effect of the CTF. It is demonstrated that the approach can be successfully applied to noisy data

Protein 3D Structure and Electron Microscopy Map Retrieval Using 3D-SURFER2.0 and EM-SURFER.

Science.gov (United States)

Han, Xusi; Wei, Qing; Kihara, Daisuke

2017-12-08

With the rapid growth in the number of solved protein structures stored in the Protein Data Bank (PDB) and the Electron Microscopy Data Bank (EMDB), it is essential to develop tools to perform real-time structure similarity searches against the entire structure database. Since conventional structure alignment methods need to sample different orientations of proteins in the three-dimensional space, they are time consuming and unsuitable for rapid, real-time database searches. To this end, we have developed 3D-SURFER and EM-SURFER, which utilize 3D Zernike descriptors (3DZD) to conduct high-throughput protein structure comparison, visualization, and analysis. Taking an atomic structure or an electron microscopy map of a protein or a protein complex as input, the 3DZD of a query protein is computed and compared with the 3DZD of all other proteins in PDB or EMDB. In addition, local geometrical characteristics of a query protein can be analyzed using VisGrid and LIGSITE CSC in 3D-SURFER. This article describes how to use 3D-SURFER and EM-SURFER to carry out protein surface shape similarity searches, local geometric feature analysis, and interpretation of the search results. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

Electron-impact excitation of the potassium atom

International Nuclear Information System (INIS)

Phelps, J.O.; Solomon, J.E.; Korff, D.F.; Lin, C.C.; Lee, E.T.P.

1979-01-01

Absolute optical electron-impact excitation functions for 24 transitions of the sharp, principal, diffuse, and fundamental spectral series of potassium have been measured. The determination of the density of the potassium vapor in the collision chamber was made by measuring the degree of transmission, by the vapor, of potassium resonance radiation generated externally in a fluorescence cell. Direct excitation functions were determined for 14 states (5S, 6S, 7S, 8S, 4P, 5P, 6P, 7P, 3D, 5D, 6D, 5F, 6F, and 7F) with the aid of known radiative-transition probabilities. Theoretical calculations of these same 14 excitation functions, as well as 4D and 4F, were carried out by means of the Born approximation. The 4P, 5P, 5S, 3D, and 4D direct excitation functions at intermediate energies (10--25 eV) were also calculated by the method of multistate close coupling, neglecting projectile--target-electron exchange. The high-energy (above 100 eV) Born-approximation cross sections agree with the experimental results for 4P and for all S states, but are lower than experimental results, by 30--40%, for the D and F states. At intermediate energies the close-coupling excitation calculations agree well with the experimental excitation functions for 4P and 5P, but are significantly higher than experimental values for 5S and 3D. The discrepancies between the experimental and theoretical results are probably due to a combination of systematic experimental errors, errors in the available transition-probability values, and errors in the theoretical excitation functions introduced by the use of approximate excited-state wave functions (Hartree-Fock-Slater), by the neglect of projectile--target-electron exchange. The polarization of the 4P-4S and 3D-4P radiation produced by electron impact was measured, and the results were used to determine the direct excitation functions of the separate magnetic sublevels of the 4P state

Tensor decomposition in electronic structure calculations on 3D Cartesian grids

International Nuclear Information System (INIS)

Khoromskij, B.N.; Khoromskaia, V.; Chinnamsetty, S.R.; Flad, H.-J.

2009-01-01

In this paper, we investigate a novel approach based on the combination of Tucker-type and canonical tensor decomposition techniques for the efficient numerical approximation of functions and operators in electronic structure calculations. In particular, we study applicability of tensor approximations for the numerical solution of Hartree-Fock and Kohn-Sham equations on 3D Cartesian grids. We show that the orthogonal Tucker-type tensor approximation of electron density and Hartree potential of simple molecules leads to low tensor rank representations. This enables an efficient tensor-product convolution scheme for the computation of the Hartree potential using a collocation-type approximation via piecewise constant basis functions on a uniform nxnxn grid. Combined with the Richardson extrapolation, our approach exhibits O(h 3 ) convergence in the grid-size h=O(n -1 ). Moreover, this requires O(3rn+r 3 ) storage, where r denotes the Tucker rank of the electron density with r=O(logn), almost uniformly in n. For example, calculations of the Coulomb matrix and the Hartree-Fock energy for the CH 4 molecule, with a pseudopotential on the C atom, achieved accuracies of the order of 10 -6 hartree with a grid-size n of several hundreds. Since the tensor-product convolution in 3D is performed via 1D convolution transforms, our scheme markedly outperforms the 3D-FFT in both the computing time and storage requirements.

3D invariant embedding model for backscattering electrons applied to materials characterization

International Nuclear Information System (INIS)

Figueroa, C.; Nieva, N.; Heluani, S.P.

2007-01-01

In this work, the results of a 3D model used to describe the fraction of backscattered electrons, together with its energy and angular distributions, are reported. This 3D model is the result of improvements in the Invariant Embedding Approach to Microanalysis (IEAM). Comparisons with experiment show that the theoretical results follow the general trend of experimental data, when parameters (such as atomic number, energy of the impinging electrons and tilted angle) are changed

3D Modeling Activity for Novel High Power Electron Guns at SLAC

International Nuclear Information System (INIS)

Krasnykh, Anatoly

2003-01-01

The next generation of powerful electronic devices requires new approaches to overcome the known limitations of existing tube technology. Multi-beam and sheet beam approaches are novel concepts for the high power microwave devices. Direct and indirect modeling methods are being developed at SLAC to meet the new requirements in the 3D modeling. The direct method of solving of Poisson's equations for the multi-beam and sheet beam guns is employed in the TOPAZ 3D tool. The combination of TOPAZ 2D and EGUN (in the beginning) with MAFIA 3D and MAGIC 3D (at the end) is used in an indirect method to model the high power electron guns. Both methods complement each other to get reliable representation of the beam trajectories. Several gun ideas are under consideration at the present time. The collected results of these simulations are discussed

3D Modeling Activity for Novel High Power Electron Guns at SLAC

CERN Document Server

Krasnykh, Anatoly K

2003-01-01

The next generation of powerful electronic devices requires new approaches to overcome the known limitations of existing tube technology. Multi-beam and sheet beam approaches are novel concepts for the high power microwave devices. Direct and indirect modeling methods are being developed at SLAC to meet the new requirements in the 3D modeling. The direct method of solving of Poisson's equations for the multi-beam and sheet beam guns is employed in the TOPAZ 3D tool. The combination of TOPAZ 2D and EGUN (in the beginning) with MAFIA 3D and MAGIC 3D (at the end) is used in an indirect method to model the high power electron guns. Both methods complement each other to get reliable representation of the beam trajectories. Several gun ideas are under consideration at the present time. The collected results of these simulations are discussed.

Electron and photon impact studies of CF3I

International Nuclear Information System (INIS)

Mason, N.J.; Eden, S.; Limao Vieire, P.; Kendall, P.; Pathak, S.; Dawes, A.; Tegeder, P.; Kitajima, M.; Okamoto, M.; Tanaka, H.; Samukawa, S.; Cho, H.; Hoffmann, S.

2002-01-01

The manufacture of ultra-large-scale-integrated circuits, requires a well collimated, specially uniform, high density plasma source operating under low pressure conditions. The main feed gases used are perfluorocarbons, however these are also strong greenhouse gases, therefore must be replaced by alternative compounds with low global warming potentials. CF 3 I is one possible replacement, due to its high photolysis rate, is expected to have a very short lifetime in the atmosphere. It is also predicted to be able to produced high yields of CF 3 radicals in any etching plasma, since its weak C - I bond should be possible to break by direct electron impact. Prior adapting existing industrial plasma reactors to use CF 3 I, it is necessary to run simulations of the reactant plasma, requiring a detailed database of the electron interactions with the feed gases, however such CF 3 I data does not exist. Thus an exhaustive series of experiments to measure elastic and inelastic scattering from CF 3 I including a study of its electronic state spectroscopy using photon absorption and electron scattering techniques were performed. Electron energy loss spectroscopy (EELS) and photo-absorption spectroscopy were employed. A comprehensive set of differential cross sections for the elastic scattering CF 3 I over the impact energy region from 1.5 to 60 eV for scattering angles between 20 and 130 were compiled. The photo-absorption spectrum is characterized by three regions, the first is a very weak continuum around centered about 4.7 eV; the second consists of four prominent band structures observed around 7.4, 8.1, 9.0 and 9.8 eV, respectively, containing vibrational structure from 7 to 10 eV; the third (above the ionization potentials) could only be studied by using EELS and additional broad peaks were observed. (nevyjel)

Electron collisions with Fe-peak elements: Forbidden transitions between the low lying valence states 3d6, 3d54s, and 3d54p of Fe III

International Nuclear Information System (INIS)

McLaughlin, B.M.; Scott, M.P.; Sunderland, A.G.; Noble, C.J.; Burke, V.M.; Ramsbottom, C.A.; Reid, R.H.G.; Hibbert, A.; Bell, K.L.; Burke, P.G.

2007-01-01

Effective collision strengths are presented for the Fe-peak element Fe III at electron temperatures (T e in degrees Kelvin) in the range 2 x 10 3 to 1 x 10 6 . Forbidden transitions results are given between the 3d 6 , 3d 5 4s, and the 3d 5 4p manifolds applicable to the modeling of laboratory and astrophysical plasmas

3D Printing: 3D Printing of Shape Memory Polymers for Flexible Electronic Devices (Adv. Mater. 22/2016).

Science.gov (United States)

Zarek, Matt; Layani, Michael; Cooperstein, Ido; Sachyani, Ela; Cohn, Daniel; Magdassi, Shlomo

2016-06-01

On page 4449, D. Cohn, S. Magdassi, and co-workers describe a general and facile method based on 3D printing of methacrylated macromonomers to fabricate shape-memory objects that can be used in flexible and responsive electrical circuits. Such responsive objects can be used in the fabrication of soft robotics, minimal invasive medical devices, sensors, and wearable electronics. The use of 3D printing overcomes the poor processing characteristics of thermosets and enables complex geometries that are not easily accessible by other techniques. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Excitation-energy-dependent resonances in x-ray emissions under near-threshold electron excitation of the Ce 3d and 4d levels

International Nuclear Information System (INIS)

Chamberlain, M.B.; Baun, W.L.

1975-01-01

Soft x-ray appearance potential spectra of the 3d and 4d levels of polycrystalline cerium metal are reported in this paper. Resonant x-ray emissions are observed when the electron-excitation energy sweeps through the ionization energies of the 3d and 4d levels. The resonant x rays excited at the 3d-level onsets are considerably more intense, and are excited at a lower electron-excitation energy than the 3d-series characteristic x rays. In the neighborhood of the 4d-electron thresholds, four line-like structures extend to approx.8 eV below the 4d-electron binding energies, while two broad and more intense structures occur above the 4d onsets, with the largest one reaching a peak intensity at 12 eV above the 4d thresholds. The resonant emissions apparently arise from the decay of threshold-excited states which are bound to the inner vacancy and have core configurations nd 9 4f 3 , (n=3,4). The exchange interaction between the three 4f electrons and the respective d-orbital vacancy spreads the 4d-threshold structures over a 20 eV range of excitation energies and the 3d-threshold structures over a much smaller range

Electron Impact Excitation-Ionization of Molecules

Science.gov (United States)

Ali, Esam Abobakr A.

In the last few decades, the study of atomic collisions by electron-impact has made significant advances. The most difficult case to study is electron impact ionization of molecules for which many approximations have to be made and the validity of these approximations can only be checked by comparing with experiment. In this thesis, I have examined the Molecular three-body distorted wave (M3DW) or Molecular four-body distorted wave (M4DW) approximations for electron-impact ionization. These models use a fully quantum mechanical approach where all particles are treated quantum mechanically and the post collision interaction (PCI) is treated to all orders of perturbation. These electron impact ionization collisions play central roles in the physics and chemistry of upper atmosphere, biofuel, the operation of discharges and lasers, radiation induced damage in biological material like damage to DNA by secondary electrons, and plasma etching processes. For the M3DW model, I will present results for electron impact single ionization of small molecules such as Water, Ethane, and Carbon Dioxide and the much larger molecules Tetrahydrofuran, phenol, furfural, 1-4 Benzoquinone. I will also present results for the four-body problem in which there are two target electrons involved in the collision. M4DW results will be presented for dissociative excitation-ionization of orientated D2. I will show that M4DW calculations using a variational wave function for the ground state that included s- and p- orbital states give better agreement to the experimental measurements than a ground state approximated as a product of two 1s-type Dyson orbitals.

Theoretical studies of atomic and quasiatomic excitations by electron and ion impact

International Nuclear Information System (INIS)

Kam, K.F.

1999-09-01

Electron emission from ion induced excitations of Ca, Sc, Ti and V metal surfaces and from electron impact on transition metal oxides CoO and TiO 2 has been studied in this thesis. Both the autoionising emission from sputtered atoms and the 3p→3d and 3s→3d excitations in the oxides reveal strong atomic features. The work has involved explaining these spectra in an atomic approach, via the use of atomic structure calculations, cross section studies and empirical/semi-empirical analyses. The other aspect of this work involves extension of current theories of electron-atom scattering in the high electron energy impact regime. Overall it is shown that much can be learned about some solid-state spectra by relating them to atomic phenomena. (author)

Electronic structure of the 3d metals. An investigation by L-shell-photoionisation

Energy Technology Data Exchange (ETDEWEB)

Richter, T.S.

2007-12-03

The 3d transition metal elements from Sc to Cu have been investigated by both photo electron emission and photo absorption. Experimental spectra in the 2p energy range are discussed based on atomic multiplet models and Hartree- Fock calculations. The samples have been evaporated from an electron bombardment crucible and excited/ionized by monochromatized synchrotron radiation. Fundamental effects and the main interactions which govern the electronic structure of the 3d metal atoms are covered. Common spectral features and trends in the series are discussed as well as the importance of many body electron correlation effects. (orig.)

Electron-impact excitation rate-coefficients and polarization of subsequent emission for Ar"+ ion

International Nuclear Information System (INIS)

Dipti; Srivastava, Rajesh

2016-01-01

Electron impact excitation in Ar"+ ions has been studied by using fully relativistic distorted wave theory. Calculations are performed to obtain the excitation cross-sections and rate-coefficients for the transitions from the ground state 3p"5 (J=3/2) to fine-structure levels of excited states 3p"44s, 3p"44p, 3p"45s, 3p"45p, 3p"43d and 3p"44d. Polarization of the radiation following the excitation has been calculated using the obtained magnetic sub-level cross-sections. Comparison of the present rate-coefficients is also done with the previously reported theoretical results for some unresolved fine structure transitions. - Highlights: • Fully relativistic distorted wave theory has been used to study the excitation of fine-structure states of Ar"+. • We have calculated electron-impact excitation cross-sections for the wide range of incident electron energies. • Electron impact excitation rate-coefficients are calculated as a function of electron temperature. • Polarization of photons emitted following the decay of the excited fine-structure states are also reported.

3D Printing of Shape Memory Polymers for Flexible Electronic Devices.

Science.gov (United States)

Zarek, Matt; Layani, Michael; Cooperstein, Ido; Sachyani, Ela; Cohn, Daniel; Magdassi, Shlomo

2016-06-01

The formation of 3D objects composed of shape memory polymers for flexible electronics is described. Layer-by-layer photopolymerization of methacrylated semicrystalline molten macromonomers by a 3D digital light processing printer enables rapid fabrication of complex objects and imparts shape memory functionality for electrical circuits. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent progress in printed 2/3D electronic devices

Science.gov (United States)

Klug, Andreas; Patter, Paul; Popovic, Karl; Blümel, Alexander; Sax, Stefan; Lenz, Martin; Glushko, Oleksandr; Cordill, Megan J.; List-Kratochvil, Emil J. W.

2015-09-01

New, energy-saving, efficient and cost-effective processing technologies such as 2D and 3D inkjet printing (IJP) for the production and integration of intelligent components will be opening up very interesting possibilities for industrial applications of molecular materials in the near future. Beyond the use of home and office based printers, "inkjet printing technology" allows for the additive structured deposition of photonic and electronic materials on a wide variety of substrates such as textiles, plastics, wood, stone, tiles or cardboard. Great interest also exists in applying IJP in industrial manufacturing such as the manufacturing of PCBs, of solar cells, printed organic electronics and medical products. In all these cases inkjet printing is a flexible (digital), additive, selective and cost-efficient material deposition method. Due to these advantages, there is the prospect that currently used standard patterning processes can be replaced through this innovative material deposition technique. A main issue in this research area is the formulation of novel functional inks or the adaptation of commercially available inks for specific industrial applications and/or processes. In this contribution we report on the design, realization and characterization of novel active and passive inkjet printed electronic devices including circuitry and sensors based on metal nanoparticle ink formulations and the heterogeneous integration into 2/3D printed demonstrators. The main emphasis of this paper will be on how to convert scientific inkjet knowledge into industrially relevant processes and applications.

Wavelengths of the 3p-3d transitions of the Co- and Fe-like ions: The effects of electron correlation

International Nuclear Information System (INIS)

Chen, Mau Hsiung.

1987-01-01

The experimental observations of the 3p 6 3d 9 2 D - 3p 5 3d 10 2 p transitions of the Co-like ions and 3p 6 3d 8 3 F 4 - 3p 5 3d 9 3 F 3 of the Fe-like ions have recently been extended to highly charged ions of heavy elements up to uranium (Z = 92). A comparison between the observed energies and calculated values from the Dirac-Fock model indicated persistent discrepancies of 3 to 4 eV for all ions. Systematic multiconfiguration Dirac-Fock calculations for these transitions have been carried out with emphases on the effects of electron correlation. The previously found discrepancies theory and experiment have mostly removed after the inclusion of the electron-electron correlation effects in the theoretical calculations. 13 refs

FIJI Macro 3D ART VeSElecT: 3D Automated Reconstruction Tool for Vesicle Structures of Electron Tomograms.

Directory of Open Access Journals (Sweden)

Kristin Verena Kaltdorf

2017-01-01

Full Text Available Automatic image reconstruction is critical to cope with steadily increasing data from advanced microscopy. We describe here the Fiji macro 3D ART VeSElecT which we developed to study synaptic vesicles in electron tomograms. We apply this tool to quantify vesicle properties (i in embryonic Danio rerio 4 and 8 days past fertilization (dpf and (ii to compare Caenorhabditis elegans N2 neuromuscular junctions (NMJ wild-type and its septin mutant (unc-59(e261. We demonstrate development-specific and mutant-specific changes in synaptic vesicle pools in both models. We confirm the functionality of our macro by applying our 3D ART VeSElecT on zebrafish NMJ showing smaller vesicles in 8 dpf embryos then 4 dpf, which was validated by manual reconstruction of the vesicle pool. Furthermore, we analyze the impact of C. elegans septin mutant unc-59(e261 on vesicle pool formation and vesicle size. Automated vesicle registration and characterization was implemented in Fiji as two macros (registration and measurement. This flexible arrangement allows in particular reducing false positives by an optional manual revision step. Preprocessing and contrast enhancement work on image-stacks of 1nm/pixel in x and y direction. Semi-automated cell selection was integrated. 3D ART VeSElecT removes interfering components, detects vesicles by 3D segmentation and calculates vesicle volume and diameter (spherical approximation, inner/outer diameter. Results are collected in color using the RoiManager plugin including the possibility of manual removal of non-matching confounder vesicles. Detailed evaluation considered performance (detected vesicles and specificity (true vesicles as well as precision and recall. We furthermore show gain in segmentation and morphological filtering compared to learning based methods and a large time gain compared to manual segmentation. 3D ART VeSElecT shows small error rates and its speed gain can be up to 68 times faster in comparison to manual

Coherence in electron-impact excitation of helium

International Nuclear Information System (INIS)

Batelaan, Hermanus.

1991-01-01

This thesis describes an experimental study into the electron-impact excitation to the 3 3 P, 3 1 D and 3 3 D states of Helium. The scattered electron and the photon, emitted by the excited atom, are measured in coincidence. The parameters, which can be varied, are the scattering angle and the kinetic energy of the projectile. Two parameters, which are used to characterize the excited state, are the angular momentum transferred to the atom, L perpendicular, and the alignment angle γ. It is shown that results of measurements on 3 1 D excitation with photon detection perpendicular to the scattering plane do not agree in the small scattering angle region with any of the model calculations currently available. Remarkable is the sign of L perpendicular, which appears to start of negatively at 60 eV. It is shown that for 3 3 P excitation the predicted large value of γ is indeed found experimentally. This supports the suggestion that exchange scattering is underestimated in model calculations for 1 P excitation. Another result is that for 1 P and 3 P excitation the behaviour of L perpendicular as a function of the scattering angle can be related at different impact energies with the help of a partial wave expansion. A scaling relation can be formulated for the behaviour of L perpendicular. The influence of a negative ion resonance to excitation of the 3 3 D state is investigated. Both in coincidence and non-coincidence measurements the presence of the resonance yields information on both the direct and indirect excitation of the 3 3 D state. It is shown that the coincident measurement gives an unique opportunity to determine the excited 3 3 D state completely. Results of measurements with photon detection in the scattering plane are given. They supplement previous 3 1 D and 3 3 D results and allow physical parameters, such as L perpendicular and γ, to be obtained. (H.W.). 132 refs.; 20 figs.; 18 tabs

Impact of packet losses in scalable 3D holoscopic video coding

Science.gov (United States)

Conti, Caroline; Nunes, Paulo; Ducla Soares, Luís.

2014-05-01

Holoscopic imaging became a prospective glassless 3D technology to provide more natural 3D viewing experiences to the end user. Additionally, holoscopic systems also allow new post-production degrees of freedom, such as controlling the plane of focus or the viewing angle presented to the user. However, to successfully introduce this technology into the consumer market, a display scalable coding approach is essential to achieve backward compatibility with legacy 2D and 3D displays. Moreover, to effectively transmit 3D holoscopic content over error-prone networks, e.g., wireless networks or the Internet, error resilience techniques are required to mitigate the impact of data impairments in the user quality perception. Therefore, it is essential to deeply understand the impact of packet losses in terms of decoding video quality for the specific case of 3D holoscopic content, notably when a scalable approach is used. In this context, this paper studies the impact of packet losses when using a three-layer display scalable 3D holoscopic video coding architecture previously proposed, where each layer represents a different level of display scalability (i.e., L0 - 2D, L1 - stereo or multiview, and L2 - full 3D holoscopic). For this, a simple error concealment algorithm is used, which makes use of inter-layer redundancy between multiview and 3D holoscopic content and the inherent correlation of the 3D holoscopic content to estimate lost data. Furthermore, a study of the influence of 2D views generation parameters used in lower layers on the performance of the used error concealment algorithm is also presented.

Impact of environmentally induced fluctuations on quantum mechanically mixed electronic and vibrational pigment states in photosynthetic energy transfer and 2D electronic spectra

Energy Technology Data Exchange (ETDEWEB)

Fujihashi, Yuta; Ishizaki, Akihito, E-mail: ishizaki@ims.ac.jp [Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585 (Japan); Fleming, Graham R. [Department of Chemistry, University of California, Berkeley and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2015-06-07

Recently, nuclear vibrational contribution signatures in two-dimensional (2D) electronic spectroscopy have attracted considerable interest, in particular as regards interpretation of the oscillatory transients observed in light-harvesting complexes. These transients have dephasing times that persist for much longer than theoretically predicted electronic coherence lifetime. As a plausible explanation for this long-lived spectral beating in 2D electronic spectra, quantum-mechanically mixed electronic and vibrational states (vibronic excitons) were proposed by Christensson et al. [J. Phys. Chem. B 116, 7449 (2012)] and have since been explored. In this work, we address a dimer which produces little beating of electronic origin in the absence of vibronic contributions, and examine the impact of protein-induced fluctuations upon electronic-vibrational quantum mixtures by calculating the electronic energy transfer dynamics and 2D electronic spectra in a numerically accurate manner. It is found that, at cryogenic temperatures, the electronic-vibrational quantum mixtures are rather robust, even under the influence of the fluctuations and despite the small Huang-Rhys factors of the Franck-Condon active vibrational modes. This results in long-lasting beating behavior of vibrational origin in the 2D electronic spectra. At physiological temperatures, however, the fluctuations eradicate the mixing, and hence, the beating in the 2D spectra disappears. Further, it is demonstrated that such electronic-vibrational quantum mixtures do not necessarily play a significant role in electronic energy transfer dynamics, despite contributing to the enhancement of long-lived quantum beating in 2D electronic spectra, contrary to speculations in recent publications.

Dissociative ionization of H2 and D2 by electron impact near threshold

NARCIS (Netherlands)

Boesten, L.G.J.; Heideman, H.G.M.

We have studied the dissciative ionization of H2 and D2 by electron impact. It is found that in the vicinity of the 2Σ+g dissociation threshold of H+2 (18.08 eV) a significant fraction of the produced protons originates from the process e + H2 → H− + H+ + e (threshold at 17.34 eV). Similar results

The degree of π electron delocalization and the formation of 3D-extensible sandwich structures.

Science.gov (United States)

Wang, Xiang; Wang, Qiang; Yuan, Caixia; Zhao, Xue-Feng; Li, Jia-Jia; Li, Debao; Wu, Yan-Bo; Wang, Xiaotai

2016-04-28

DFT B3LYP/6-31G(d) calculations were performed to examine the feasibility of graphene-like C42H18 and starbenzene C6(BeH)6 (SBz) polymers as ligands of 3D-extensible sandwich compounds (3D-ESCs) with uninterrupted sandwich arrays. The results revealed that sandwich compounds with three or more C42H18 ligands were not feasible. The possible reason may be the localization of π electrons on certain C6 hexagons due to π-metal interactions, which makes the whole ligand lose its electronic structure basis (higher degree of π electron delocalization) to maintain the planar structure. For comparison, with the aid of benzene (Bz) molecules, the SBz polymers can be feasible ligands for designing 3D-ESCs because the C-Be interactions in individual SBz are largely ionic, which will deter the π electrons on one C6 ring from connecting to those on neighbouring C6 rings. This means that high degree of π electron delocalization is not necessary for maintaining the planarity of SBz polymers. Such a locally delocalized π electron structure is desirable for the ligands of 3D-ESCs. Remarkably, the formation of a sandwich compound with SBz is thermodynamically more favourable than that found for bis(Bz)chromium. The assembly of 3D-ESCs is largely exothermic, which will facilitate future experimental synthesis. The different variation trends on the HOMO-LUMO gaps in different directions (relative to the sandwich axes) suggest that they can be developed to form directional conductors or semiconductors, which may be useful in the production of electronic devices.

Electron impact excitation of copper atoms

International Nuclear Information System (INIS)

Stumpf, B.J.

1993-01-01

The optical excitation function method has been used in a crossed atom and electron beam arrangement to measure the electron impact cross section of the copper 4 2 P → 4 2 S resonance lines (324.8, 327.4 nm) from threshold (3.8 eV) to 8 eV. Relative experimental cross section data are normalized at an energy of 1000 eV with respect to first Born theory that includes the 4 2 S → 4 2 P resonance transition with an oscillator strength of 0.652 and cascading from the (3d 10 nd) 2 D states with n = 4, hor-ellipsis 10. The measured Cu 4 2 S 4 → 4 2 P cross section is compared with recent theoretical calculations in close-coupling approximation. Very good agreement is found with the ten-state close-coupling theory of Scheibner

The optical design of 3D ICs for smartphone and optro-electronics sensing module

Science.gov (United States)

Huang, Jiun-Woei

2018-03-01

Smartphone require limit space for image system, current lens, used in smartphones are refractive type, the effective focal length is limited the thickness of phone physical size. Other, such as optro-electronics sensing chips, proximity optical sensors, and UV indexer chips are integrated into smart phone with limit space. Due to the requirement of multiple lens in smartphone, proximity optical sensors, UV indexer and other optro-electronics sensing chips in a limited space of CPU board in future smart phone, optro-electronics 3D IC's integrated with optical lens or components may be a key technology for 3 C products. A design for reflective lens is fitted to CMOS, proximity optical sensors, UV indexer and other optro-electronics sensing chips based on 3-D IC. The reflective lens can be threes times of effective focal lens, and be able to resolve small object. The system will be assembled and integrated in one 3-D IC more easily.

Towards automated electron holographic tomography for 3D mapping of electrostatic potentials

Energy Technology Data Exchange (ETDEWEB)

Wolf, Daniel, E-mail: Daniel.Wolf@Triebenberg.de [Triebenberg Laboratory, Institute of Structure Physics, Technische Universitaet Dresden, 01062 Dresden (Germany); Lubk, Axel; Lichte, Hannes [Triebenberg Laboratory, Institute of Structure Physics, Technische Universitaet Dresden, 01062 Dresden (Germany); Friedrich, Heiner [Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Sorbonnelaan 16, 3584 CA, Utrecht (Netherlands)

2010-04-15

Electron-holographic tomography (EHT), that is, the combination of off-axis electron holography with electron tomography, was successfully applied for the quantitative 3D mapping of electrostatic potentials at the nanoscale. Here we present the first software package (THOMAS) for semi-automated acquisition of holographic tilt series, a prerequisite for efficient data collection. Using THOMAS, the acquisition time for a holographic tilt series, consisting of object and reference holograms, is reduced by a factor of five on average, compared to the previous, completely manual approaches. Moreover, the existing software packages for retrieving amplitude and phase information from electron holograms have been extended, now including a one-step procedure for holographic tilt series reconstruction. Furthermore, a modified SIRT algorithm (WSIRT) was implemented for the quantitative 3D reconstruction of the electrostatic potential from the aligned phase tilt series. Finally, the application of EHT to a polystyrene latex sphere test-specimen and a pn-doped Ge 'needle'-shaped specimen are presented, illustrating the quantitative character of EHT. For both specimens the mean inner potential (MIP) values were accurately determined from the reconstructed 3D potential. For the Ge specimen, additionally the 'built-in' voltage across the pn junction of 0.5 V was obtained.

Nanoparticle imaging. 3D structure of individual nanocrystals in solution by electron microscopy.

Science.gov (United States)

Park, Jungwon; Elmlund, Hans; Ercius, Peter; Yuk, Jong Min; Limmer, David T; Chen, Qian; Kim, Kwanpyo; Han, Sang Hoon; Weitz, David A; Zettl, A; Alivisatos, A Paul

2015-07-17

Knowledge about the synthesis, growth mechanisms, and physical properties of colloidal nanoparticles has been limited by technical impediments. We introduce a method for determining three-dimensional (3D) structures of individual nanoparticles in solution. We combine a graphene liquid cell, high-resolution transmission electron microscopy, a direct electron detector, and an algorithm for single-particle 3D reconstruction originally developed for analysis of biological molecules. This method yielded two 3D structures of individual platinum nanocrystals at near-atomic resolution. Because our method derives the 3D structure from images of individual nanoparticles rotating freely in solution, it enables the analysis of heterogeneous populations of potentially unordered nanoparticles that are synthesized in solution, thereby providing a means to understand the structure and stability of defects at the nanoscale. Copyright © 2015, American Association for the Advancement of Science.

3D Observation of GEMS by Electron Tomography

Science.gov (United States)

Matsuno, Junya; Miyake, Akira; Tsuchiyama, Akira; Nakamura-Messenger, Keiko; Messenger, Scott

2014-01-01

Amorphous silicates in chondritic porous interplanetary dust particles (CP-IDPs) coming from comets are dominated by glass with embedded metal and sulfides (GEMS). GEMS grains are submicron-sized rounded objects (typically 100-500) nm in diameter) with anaometer-sized (10-50 nm) Fe-Ni metal and sulfide grains embedded in an amorphous silicate matrix. Several formation processes for GEMS grains have been proposed so far, but these models are still being debated [2-5]. Bradley et al. proposed that GEMS grains are interstellar silicate dust that survived various metamorphism or alteration processes in the protoplanetary disk and that they are amorphiation products of crystalline silicates in the interstellar medium by sputter-deposition of cosmic ray irradiation, similar to space weathering [2,4]. This consideration is based on the observation of nano-sized crystals (approximately 10 nm) called relict grains in GEMS grains and their shapes are pseudomorphs to the host GEMS grains. On the other hand, Keller and Messenger proposed that most GEMS formed in the protoplanetary disk as condensates from high temperature gas [3,5]. This model is based on the fact that most GEMS grains have solar isotopic compositions and have extremely heterogeneous and non-solar elemental compositions. Keller and Messenger (2011) also reported that amorphous silicates in GEMS grains are surrounded by sulfide grains, which formed as sulfidization of metallic iron grains located on the GEMS surface. The previous studies were performed with 2D observation by using transmission electron microscopy (TEM) or scanning TEM (STEM). In order to understand the structure of GEMS grains described above more clearly, we observed 3D structure of GEMS grains by electron tomography using a TEM/STEM (JEM-2100F, JEOL) at Kyoto University. Electron tomography gives not only 3D structures but also gives higher spatial resolution (approximately a few nm) than that in conventional 2D image, which is restricted by

A desktop 3D printer with dual extruders to produce customised electronic circuitry

Science.gov (United States)

Butt, Javaid; Onimowo, Dominic Adaoiza; Gohrabian, Mohammed; Sharma, Tinku; Shirvani, Hassan

2018-03-01

3D printing has opened new horizons for the manufacturing industry in general, and 3D printers have become the tools for technological advancements. There is a huge divide between the pricing of industrial and desktop 3D printers with the former being on the expensive side capable of producing excellent quality products and latter being on the low-cost side with moderate quality results. However, there is a larger room for improvements and enhancements for the desktop systems as compared to the industrial ones. In this paper, a desktop 3D printer called Prusa Mendel i2 has been modified and integrated with an additional extruder so that the system can work with dual extruders and produce bespoke electronic circuits. The communication between the two extruders has been established by making use of the In-Chip Serial Programming port on the Arduino Uno controlling the printer. The biggest challenge is to control the flow of electric paint (to be dispensed by the new extruder) and CFD (Computational Fluid Dynamics) analysis has been carried out to ascertain the optimal conditions for proper dispensing. The final product is a customised electronic circuit with the base of plastic (from the 3D printer's extruder) and electronic paint (from the additional extruder) properly dispensed to create a live circuit on a plastic platform. This low-cost enhancement to a desktop 3D printer can provide a new prospect to produce multiple material parts where the additional extruder can be filled with any material that can be properly dispensed from its nozzle.

4D Electron Tomography

Science.gov (United States)

Kwon, Oh-Hoon; Zewail, Ahmed H.

2010-06-01

Electron tomography provides three-dimensional (3D) imaging of noncrystalline and crystalline equilibrium structures, as well as elemental volume composition, of materials and biological specimens, including those of viruses and cells. We report the development of 4D electron tomography by integrating the fourth dimension (time resolution) with the 3D spatial resolution obtained from a complete tilt series of 2D projections of an object. The different time frames of tomograms constitute a movie of the object in motion, thus enabling studies of nonequilibrium structures and transient processes. The method was demonstrated using carbon nanotubes of a bracelet-like ring structure for which 4D tomograms display different modes of motion, such as breathing and wiggling, with resonance frequencies up to 30 megahertz. Applications can now make use of the full space-time range with the nanometer-femtosecond resolution of ultrafast electron tomography.

Electron-impact excitation autoionization of Ga II

International Nuclear Information System (INIS)

Pindzola, M.S.; Griffin, D.C.; Bottcher, C.

1982-01-01

The general-reaction theory of Feshbach is applied, within the framework of the distorted-wave approximation, to the calculation of excitation-autoionization resonances in the electron-impact ionization of Ga + . Although the spectrum of autoionizing levels for Ga + is quite complex, we focus our attention on the important 3d 10 4s 2 → 3d 9 4s 2 4p inner-shell excitations. For excitation of the 3d 9 4s 2 4p 1 P 1 autoionizing level we make a general-reaction-theory calculation for the dominant partial-wave cross section and compute a typical resonance profile in the ejected-electron differential cross section. We find that the quantum-mechanical interference between the direct and indirect processes has a small effect on the total ionization cross section. Employing an independent-processes approximation we calculate excitation-autoionization contributions to all twelve levels of the 3d 9 4s 2 4p configuration. Using the results of our calculations and their comparison with a recent crossed-beam experiment by Rogers et al., we discuss the accuracy of the distorted-wave method and the effects of configuration interaction on energy levels and excitation cross sections

Electron-impact excitation of Zn II

International Nuclear Information System (INIS)

Msezane, A.Z.; Henry, R.J.W.

1982-01-01

Collision strengths are calculated for excitation of Zn II from the 4s ground state to excited states 4p, 3d 9 4s 2 , 5s, and 4d in a five-state close-coupling approximation for the electron-impact energy range 15 5 3d 10 4s 2 in a two-state close-coupling approximation for the same energy range. Accurate target functions are used in the expansion. Very good agreement with measurements of absolute emission cross sections of Rogers et al. is obtained for energy region 15< E<100 eV, when cascade contributions are included. Poorer agreement is obtained with experiment for excitation of the 5s state, owing to sensitivities in the close-coupling approximation

Electron capture into the n = 3 states of hydrogen by proton impact on CO, CO2, and N2O

International Nuclear Information System (INIS)

Loyd, D.H.; Dawson, H.R.

1979-01-01

Absolute cross sections for electron capture into the 3s, 3p, and 3d states of hydrogen have been measured for 2.2--8.2-keV proton impact on CO, CO 2 , and N 2 O. The relative magnitudes of the 3s, 3p, and 3d cross sections for CO are very similar to cross sections previously measured for elemental gases. The CO 2 and N 2 O cross sections have a very different relative distribution among the 3s, 3p, and 3d states compared to all other gases studied in this laboratory, with the 3p cross section being so small that only an estimate of the upper limit to the cross section was possible

The business impact and value of 3-D seismic

International Nuclear Information System (INIS)

Aylor, W.K.

1996-01-01

3-D Seismic has had a profound and lasting impact on the hydrocarbon exploration and production industry. It is a technology which is often excellent at assessing the risk associated with trap definition, seal and reservoir distribution, the very parameters which are the most critical to optimizing the economics associated with E and P projects. This paper discusses Amoco Corporation's experience with 3-D Seismic when used for new field rate acceleration, older field extension, and wildcat exploration. Its emphasis is on assessing the value added by 3-D by reviewing recent E and P experiences in a post-appraisal mode and then in applying the lessons learned from these analyses and case histories to potential new projects. This work is significant because it first assesses the impact 3-D has had on a large number of business situations at Amoco; that is, it is based on data collected on159 3-D surveys acquired at Amoco between 1991--1994. Second, it uses the data collected from these surveys and applies the business improvements observed in the data to typical international business opportunities to quantify, in expected value $ terms, the value that the technology brings to an average project. Finally, it looks at project economics not only from an oil company perspective, but from the standpoint of a host government, with a discussion of insights and implications of the data, economics and techniques utilized

Electron-beam-induced welding of 3D nano-objects from beneath

International Nuclear Information System (INIS)

Moskalenko, A V; Burbridge, D J; Viau, G; Gordeev, S N

2007-01-01

Exposure of a sample to the electron beam in a scanning electron microscope (SEM) results in the growth of a film of amorphous carbon due to decomposition of hydrocarbon molecules, which are always present in small quantities in the SEM chamber. This growth is induced mainly by secondary electrons backscattered by atoms of both the sample and substrate. We show that, because the secondary electrons are spread beyond the exposed area, this deposit can be grown in areas of geometric shadow and therefore can be used for bonding of different complex 3D nano-objects to a substrate. This is demonstrated by welding 100 nm Fe-Co-Ni nanoparticles to the surface of 2D graphite. The tip of an atomic force microscope was used to probe the mechanical properties of the formed nanostructures. We observed that, for layers thicker than 25 nm, the nanoparticle is bonded so strongly that it is easier to break the particle than to separate it from the substrate

Dynamics of electron emission in double photoionization processes near the krypton 3d threshold

International Nuclear Information System (INIS)

Penent, F; Sheinerman, S; Andric, L; Lablanquie, P; Palaudoux, J; Becker, U; Braune, M; Viefhaus, J; Eland, J H D

2008-01-01

Two-electron emission following photoabsorption near the Kr 3d threshold is investigated both experimentally and theoretically. On the experimental side, electron/electron coincidences using a magnetic bottle time-of-flight spectrometer allow us to observe the complete double photo ionization (DPI) continua of selected Kr 2+ final states, and to see how these continua are affected by resonant processes in the vicinity of the Kr 3d threshold. The analysis is based on a quantum mechanical approach that takes into account the contribution of three different processes: (A) Auger decay of the inner 3d vacancy with the associated post-collision interaction (PCI) effects, (B) capture of slow photoelectrons into discrete states followed by valence multiplet decay (VMD) of the excited ionic states and (C) valence shell DPI. The dominant process for each Kr 2+ (4p -2 ) final state is the photoionization of the inner shell followed by Auger decay of the 3d vacancies. Moreover, for the 4p -2 ( 3 P) and 4p -2 ( 1 D) final ionic states an important contribution comes from the processes of slow photoelectron capture followed by VMD as well as from double ionization of the outer shell involving also VMD

Electron-impact excitation of atomic-argon 3p54s-3p55p spectral transitions

International Nuclear Information System (INIS)

Bogdanova, I.P.; Yurgenson, S.V.

1990-01-01

Cross sections of excitation of some spectral lines of argon corresponding to transitions from 3p 5 5p-levels are measured using a pulsed electron beam. Cross sections of level excitation are estimated. It is shown that in transition from 3p 5 4p-levels to 3p 5 5p-levels, the cross section of levels by means of the electron impact decreases 20 times

Influence of Fibre Architecture on Impact Damage Tolerance in 3D Woven Composites

Science.gov (United States)

Potluri, P.; Hogg, P.; Arshad, M.; Jetavat, D.; Jamshidi, P.

2012-10-01

3D woven composites, due to the presence of through-thickness fibre-bridging, have the potential to improve damage tolerance and at the same time to reduce the manufacturing costs. However, ability to withstand damage depends on weave topology as well as geometry of individual tows. There is an extensive literature on damage tolerance of 2D prepreg laminates but limited work is reported on the damage tolerance of 3D weaves. In view of the recent interest in 3D woven composites from aerospace as well as non-aerospace sectors, this paper aims to provide an understanding of the impact damage resistance as well as damage tolerance of 3D woven composites. Four different 3D woven architectures, orthogonal, angle interlocked, layer-to-layer and modified layer-to-layer structures, have been produced under identical weaving conditions. Two additional structures, Unidirectional (UD) cross-ply and 2D plain weave, have been developed for comparison with 3D weaves. All the four 3D woven laminates have similar order of magnitude of damage area and damage width, but significantly lower than UD and 2D woven laminates. Damage Resistance, calculated as impact energy per unit damage area, has been shown to be significantly higher for 3D woven laminates. Rate of change of CAI strength with impact energy appears to be similar for all four 3D woven laminates as well as UD laminate; 2D woven laminate has higher rate of degradation with respect to impact energy. Undamaged compression strength has been shown to be a function of average tow waviness angle. Additionally, 3D weaves exhibit a critical damage size; below this size there is no appreciable reduction in compression strength. 3D woven laminates have also exhibited a degree of plasticity during compression whereas UD laminates fail instantly. The experimental work reported in this paper forms a foundation for systematic development of computational models for 3D woven architectures for damage tolerance.

A simple, low-cost conductive composite material for 3D printing of electronic sensors.

Science.gov (United States)

Leigh, Simon J; Bradley, Robert J; Purssell, Christopher P; Billson, Duncan R; Hutchins, David A

2012-01-01

3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes ('rapid prototyping') before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term 'carbomorph' and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes.

A simple, low-cost conductive composite material for 3D printing of electronic sensors.

Directory of Open Access Journals (Sweden)

Simon J Leigh

Full Text Available 3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes ('rapid prototyping' before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term 'carbomorph' and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes.

Angular distribution of Auger electrons due to 3d-shell ionization of krypton

Science.gov (United States)

Omidvar, K.

1977-01-01

Cross sections for electron impact ionization of krypton due to ejection of a 3rd shell electron have been calculated using screened hydrogenic and Hartree-Slater wave functions for target atom. While the total ionization cross sections in the two approximations are within 10% of each other, the Auger electron angular distribution, related to cross sections for specific magnetic quantum numbers of the 3rd electrons, is widely different in the two approximations. The angular distribution due to Hartree-Slater approximation is in excellent agreement with measurement. The physical reason for the discrepancies in the two approximations is explained.

A self-healing 3D woven fabric reinforced shape memory polymer composite for impact mitigation

International Nuclear Information System (INIS)

Nji, Jones; Li, Guoqiang

2010-01-01

In this paper, a three-dimensional (3D) woven fabric reinforced shape memory polymer composite for impact mitigation was proposed, fabricated, programmed using a three-step strain-controlled thermomechanical cycle at a pre-strain level of 5% and machined to two groups of specimens (G1 and G2) with dimensions 152.4 mm × 101.6 mm × 12.7 mm. The specimens were impact tested, transversely, centrally and repeatedly with 32 and 42 J of energy. G1 specimens were healed after each impact until perforation occurred. G2 specimens were not healed after each impact and served as controls. At 32 J impact energy, G2 specimens were perforated at the 9th impact while G1 specimens lasted until the 15th impact; at 42 J impact energy, G2 specimens were perforated at the 5th impact while G1 specimens were perforated at the 7th impact. Visual inspection, C-scan, and scanning electron microscopy techniques were used to evaluate damage, failure modes, and healing efficiency

Cell for studying electron-adsorbed gas interactions; Cellule d'etudes des interactions electron-gaz adsorbe

Energy Technology Data Exchange (ETDEWEB)

Golowacz, H; Degras, D A [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires, Deptartement de Physique des Plasmas et de la Fusion Controlee, Service de Physique Appliquee, Service de Physique des Interractions Electroniques, Section d' Etude des Interactions Gaz-Solides

1967-07-01

The geometry and the technology of a cell used for investigations on electron-adsorbed gas interactions are described. The resonance frequencies of the surface ions which are created by the electron impact on the adsorbed gas are predicted by simplified calculations. The experimental data relative to carbon monoxide and neon are in good agreement with these predictions. (authors) [French] Les caracteristiques geometriques et technologiques generales d'une cellule d'etude des interactions entre un faisceau d'electrons et un gaz adsorbe sont donnees. Un calcul simplifie permet de prevoir les frequences de resonance des ions de surface crees par l'impact des electrons sur le gaz adsorbe. Les donnees experimentales sur l'oxyde de carbone et le neon confirment les previsions du calcul. (auteurs)

MO-H-19A-03: Patient Specific Bolus with 3D Printing Technology for Electron Radiotherapy

International Nuclear Information System (INIS)

Zou, W; Swann, B; Siderits, R; McKenna, M; Khan, A; Yue, N; Zhang, M; Fisher, T

2014-01-01

Purpose: Bolus is widely used in electron radiotherapy to achieve desired dose distribution. 3D printing technologies provide clinicians with easy access to fabricate patient specific bolus accommodating patient body surface irregularities and tissue inhomogeneity. This study presents the design and the clinical workflow of 3D printed bolus for patient electron therapy in our clinic. Methods: Patient simulation CT images free of bolus were exported from treatment planning system (TPS) to an in-house developed software package. Bolus with known material properties was designed in the software package and then exported back to the TPS as a structure. Dose calculation was carried out to examine the coverage of the target. After satisfying dose distribution was achieved, the bolus structure was transferred in Standard Tessellation Language (STL) file format for the 3D printer to generate the machine codes for printing. Upon receiving printed bolus, a quick quality assurance was performed with patient resimulated with bolus in place to verify the bolus dosimetric property before treatment started. Results: A patient specific bolus for electron radiotherapy was designed and fabricated in Form 1 3D printer with methacrylate photopolymer resin. Satisfying dose distribution was achieved in patient with bolus setup. Treatment was successfully finished for one patient with the 3D printed bolus. Conclusion: The electron bolus fabrication with 3D printing technology was successfully implemented in clinic practice

MO-H-19A-03: Patient Specific Bolus with 3D Printing Technology for Electron Radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Zou, W; Swann, B; Siderits, R; McKenna, M; Khan, A; Yue, N; Zhang, M [Rutgers University, New Brunswick, NJ (United States); Fisher, T [Memorial Medical Center, Modesto, CA (United States)

2014-06-15

Purpose: Bolus is widely used in electron radiotherapy to achieve desired dose distribution. 3D printing technologies provide clinicians with easy access to fabricate patient specific bolus accommodating patient body surface irregularities and tissue inhomogeneity. This study presents the design and the clinical workflow of 3D printed bolus for patient electron therapy in our clinic. Methods: Patient simulation CT images free of bolus were exported from treatment planning system (TPS) to an in-house developed software package. Bolus with known material properties was designed in the software package and then exported back to the TPS as a structure. Dose calculation was carried out to examine the coverage of the target. After satisfying dose distribution was achieved, the bolus structure was transferred in Standard Tessellation Language (STL) file format for the 3D printer to generate the machine codes for printing. Upon receiving printed bolus, a quick quality assurance was performed with patient resimulated with bolus in place to verify the bolus dosimetric property before treatment started. Results: A patient specific bolus for electron radiotherapy was designed and fabricated in Form 1 3D printer with methacrylate photopolymer resin. Satisfying dose distribution was achieved in patient with bolus setup. Treatment was successfully finished for one patient with the 3D printed bolus. Conclusion: The electron bolus fabrication with 3D printing technology was successfully implemented in clinic practice.

SU-C-213-06: Dosimetric Verification of 3D Printed Electron Bolus

International Nuclear Information System (INIS)

Rasmussen, K; Corbett, M; Pelletier, C; Huang, Z; Feng, Y; Jung, J

2015-01-01

Purpose: To determine the dosimetric effect of 3D printed bolus in an anthropomorphic phantom. Methods: Conformable bolus material was generated for an anthropomorphic phantom from a DICOM volume. The bolus generated was a uniform expansion of 5mm applied to the nose region of the phantom, as this is a difficult area to uniformly apply bolus clinically. A Printrbot metal 3D Printer using PLA plastic generated the bolus. A 9MeV anterior beam with a 5cm cone was used to deliver dose to the nose of the phantom. TLD measurements were compared to predicted values at the phantom surface. Film planes were analyzed for the printed bolus, a standard 5mm bolus sheet placed on the phantom, and the phantom with no bolus applied to determine depth and dose distributions. Results: TLDs measured within 2.5% of predicted value for the 3D bolus. Film demonstrated a more uniform dose distribution in the nostril region for the 3d printed bolus than the standard bolus. This difference is caused by the air gap created around the nostrils by the standard bolus, creating a secondary build-up region. Both demonstrated a 50% central axis dose shift of 5mm relative to the no bolus film. HU for the bolus calculated the PLA electron density to be ∼1.1g/cc. Physical density was measured to be 1.3g/cc overall. Conclusion: 3D printed PLA bolus demonstrates improved dosimetric performance to standard bolus for electron beams with complex phantom geometry

SU-C-213-06: Dosimetric Verification of 3D Printed Electron Bolus

Energy Technology Data Exchange (ETDEWEB)

Rasmussen, K; Corbett, M; Pelletier, C; Huang, Z; Feng, Y; Jung, J [East Carolina Univ, Greenville, NC (United States)

2015-06-15

Purpose: To determine the dosimetric effect of 3D printed bolus in an anthropomorphic phantom. Methods: Conformable bolus material was generated for an anthropomorphic phantom from a DICOM volume. The bolus generated was a uniform expansion of 5mm applied to the nose region of the phantom, as this is a difficult area to uniformly apply bolus clinically. A Printrbot metal 3D Printer using PLA plastic generated the bolus. A 9MeV anterior beam with a 5cm cone was used to deliver dose to the nose of the phantom. TLD measurements were compared to predicted values at the phantom surface. Film planes were analyzed for the printed bolus, a standard 5mm bolus sheet placed on the phantom, and the phantom with no bolus applied to determine depth and dose distributions. Results: TLDs measured within 2.5% of predicted value for the 3D bolus. Film demonstrated a more uniform dose distribution in the nostril region for the 3d printed bolus than the standard bolus. This difference is caused by the air gap created around the nostrils by the standard bolus, creating a secondary build-up region. Both demonstrated a 50% central axis dose shift of 5mm relative to the no bolus film. HU for the bolus calculated the PLA electron density to be ∼1.1g/cc. Physical density was measured to be 1.3g/cc overall. Conclusion: 3D printed PLA bolus demonstrates improved dosimetric performance to standard bolus for electron beams with complex phantom geometry.

Binary and ternary recombination of D3+ ions with electrons in He-D2 plasma

International Nuclear Information System (INIS)

Glosik, J.; Korolov, I.; Plasil, R.; Kotrik, T.; Dohnal, P.; Novotny, O.; Varju, J.; Roucka, S.; Greene, Chris H.; Kokoouline, V.

2009-01-01

An experimental study is reported about the recombination of D 3 + ions with electrons in a low-temperature plasma (200-300 K) consisting of He with a small admixture of D 2 . At several temperatures, the pressure dependence of the apparent binary recombination rate coefficient (α eff ) was measured over a broad range of helium pressures (200-2000 Pa). The binary and ternary recombination rate coefficients were obtained from measured pressure dependences of α eff . The binary recombination rate coefficient obtained α bin (300 K)=(2.7±0.9)x10 -8 cm 3 s -1 is in agreement with recent theory. The ternary recombination rate coefficient obtained is K He (300 K)=(1.8±0.6)x10 -25 cm 6 s -1 . In analogy with the recently described process of helium-assisted ternary recombination of H 3 + ions, it is suggested that the ternary helium-assisted recombination of D 3 + ions proceeds through the formation of a neutral long-lived highly excited Rydberg molecule D 3 followed by a collision with a He atom.

Binary and ternary recombination of D3+ ions with electrons in He-D2 plasma

Science.gov (United States)

Glosík, J.; Korolov, I.; Plašil, R.; Kotrík, T.; Dohnal, P.; Novotný, O.; Varju, J.; Roučka, Š.; Greene, Chris H.; Kokoouline, V.

2009-10-01

An experimental study is reported about the recombination of D3+ ions with electrons in a low-temperature plasma (200-300 K) consisting of He with a small admixture of D2 . At several temperatures, the pressure dependence of the apparent binary recombination rate coefficient (αeff) was measured over a broad range of helium pressures (200-2000 Pa). The binary and ternary recombination rate coefficients were obtained from measured pressure dependences of αeff . The binary recombination rate coefficient obtained αbin(300K)=(2.7±0.9)×10-8cm3s-1 is in agreement with recent theory. The ternary recombination rate coefficient obtained is KHe(300K)=(1.8±0.6)×10-25cm6s-1 . In analogy with the recently described process of helium-assisted ternary recombination of H3+ ions, it is suggested that the ternary helium-assisted recombination of D3+ ions proceeds through the formation of a neutral long-lived highly excited Rydberg molecule D3 followed by a collision with a He atom.

Electron capture into the 3s, 3p, 3d states and the 3, 4, 5, 6 levels of H by proton impact on gases

International Nuclear Information System (INIS)

Lenormand, J.

1976-01-01

The excitation of the Hsub(α), Hsub(β), Hsub(γ), Hsub(delta) Balmer lines by means of 15-85keV protons incident on noble-gas and molecular targets have been observed. Absolute cross-sections for electron capture by the 3l (l=s, p, d) states and the 3, 4, 5, 6 levels of hydrogen atom have been determined with He, Ne, Ar, Kr, Xe, N 2 and O 2 . Polarizations of the Hsub(α) and Hsub(β) lines have been measured for 10-70keV protons on Ar, Kr, and Xe. Absolute cross-sections for the emission of the 3914A band of N 2 + have been obtained for 10-100keV protons on the gaseous nitrogen target [fr

TNO : The impact of 3-D printing on supply chain management

NARCIS (Netherlands)

Janssen, G.R.; Blankers, I.J.; Moolenburgh, E.A.; Posthumus, A.L.

2014-01-01

It is said that 3-D printing, officially known as additive manufacturing, has the potential to become the biggest single disruptive phenomenon to impact global industry since mass production lines were introduced early in the twentieth century. McKinsey Global Institute named 3-D printing as one of

3D imaging by serial block face scanning electron microscopy for materials science using ultramicrotomy.

Science.gov (United States)

Hashimoto, Teruo; Thompson, George E; Zhou, Xiaorong; Withers, Philip J

2016-04-01

Mechanical serial block face scanning electron microscopy (SBFSEM) has emerged as a means of obtaining three dimensional (3D) electron images over volumes much larger than possible by focused ion beam (FIB) serial sectioning and at higher spatial resolution than achievable with conventional X-ray computed tomography (CT). Such high resolution 3D electron images can be employed for precisely determining the shape, volume fraction, distribution and connectivity of important microstructural features. While soft (fixed or frozen) biological samples are particularly well suited for nanoscale sectioning using an ultramicrotome, the technique can also produce excellent 3D images at electron microscope resolution in a time and resource-efficient manner for engineering materials. Currently, a lack of appreciation of the capabilities of ultramicrotomy and the operational challenges associated with minimising artefacts for different materials is limiting its wider application to engineering materials. Consequently, this paper outlines the current state of the art for SBFSEM examining in detail how damage is introduced during slicing and highlighting strategies for minimising such damage. A particular focus of the study is the acquisition of 3D images for a variety of metallic and coated systems. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Simulation of diode electron source of PSTA latex EBM using OPERA-3D software

International Nuclear Information System (INIS)

Taufik; Darsono

2014-01-01

Electron beam transport from E-gun to the atmospheres in EBM is determined by main parameters of beam transports such as E-gun, accelerator tube, beam optics (focusing and scanning magnets). In principle the beam transport will optimum if the electron beam travels in axial axes of accelerator tubes, and the beam optics works properly. The EBM E-gun structure of PSTA uses diode type with Pierce cathode where beam transport yield will be affected by electrode voltage of the accelerator tube. To answer above hypothesis the E-gun and accelerator tube will be simulated by making a model used accelerator software programme which is called OPERA-3D. Beam transport parameters, such as distance between cathode and anode of E-gun, accelerator electrode HV, and the symmetry of cathode Pierce E-gun with anode electrode of accelerator tube, will be investigated their impacts to direction and shape of beam transports. The simulation results shows that the three parameters affects to the direction and shape of the beam transport. Diode type of electron gun cannot result parallel electron beam, but the best beam transport of this type electron gun are obtained at the accelerator voltage 300 kV, and the distance between cathode and anode of E-gun 6.1 mm where they are in the symmetry condition. (author)

Relativistic quantum Hall conductivity for 3D and 2D electron plasma in an external magnetic field

International Nuclear Information System (INIS)

Gonzalez Felipe, R.; Perez Martinez, A.; Perez-Rojas, H.

1990-05-01

The complete antisymmetric form of the conductivity tensor in the static limit, as well as the expression for the Hall conductivity, is obtained for the relativistic 3D and 2D electron gas in a magnetic field. The non-relativistic 2D limit is also discussed. The typical step form of the 2D Hall conductivity at zero temperature is obtained under the simple hypothesis of constancy of the chemical potential. (author). 6 refs, 1 fig

Dynamic scattering theory for dark-field electron holography of 3D strain fields

International Nuclear Information System (INIS)

Lubk, Axel; Javon, Elsa; Cherkashin, Nikolay; Reboh, Shay; Gatel, Christophe; Hÿtch, Martin

2014-01-01

Dark-field electron holography maps strain in crystal lattices into reconstructed phases over large fields of view. Here we investigate the details of the lattice strain–reconstructed phase relationship by applying dynamic scattering theory both analytically and numerically. We develop efficient analytic linear projection rules for 3D strain fields, facilitating a straight-forward calculation of reconstructed phases from 3D strained materials. They are used in the following to quantify the influence of various experimental parameters like strain magnitude, specimen thickness, excitation error and surface relaxation. - Author-Highlights: • We derive a simple dynamic scattering formalism for dark field electron holography based on a perturbative two-beam theory. • The formalism facilitates the projection of 3D strain fields by a simple weighting integral. • The weighted projection depends analytically on the diffraction order, the excitation error and the specimen thickness. • The weighting integral formalism represents an important prerequisite towards the development of tomographic strain reconstruction techniques

Electronic excitation of Na atom by electron impact

International Nuclear Information System (INIS)

Bielschowsky, C.E.; Souza, G.G.B. de; Lucas, C.A.; Nogueira, J.C.

1988-01-01

Electronic excitation of the 3s-3p transition in the Na atom was studied by intermediate energy electron impact spectroscopy. Differential Cross Sections (DCS) and Generalized Oscillator Strenghts (GOS) were determined experimentally for 1 KeV electrons. Theoretical results within the First Born Approximation as well as Glauber theory, were also performed. (A.C.A.S.) [pt

Electron impact excitation of the iron peak element Fe II

International Nuclear Information System (INIS)

Ramsbottom, C.A.; Scott, M.P.; Bell, K.L.; McLaughlin, B.M.; Burke, P.G.; Keenan, F.P.; Sunderland, A.G.; Burke, V.M.; Noble, C.J.

2002-01-01

Effective collision strengths for electron-impact excitation of Fe II are presented for all sextet-to-quartet transitions among the 38 LS states formed from the basis configurations 3d 6 4s, 3d 7 and 3d 6 4p. A total of 112 individual transitions are considered at electron temperatures in the range 30-100,000 K, encompassing values of importance for applications in astrophysics as well as laboratory plasmas. A limited comparison is made with earlier theoretical work and large differences are found to occur at the temperatures considered. In particular, it is found that the inclusion or omission of some (N+1)-bound configurations in the Hamiltonian matrices describing the collision process can have a huge effect on the resulting effective collision strengths, by up to a factor of four in some cases. (author)

Non-dipole effects in spin polarization of photoelectrons from 3d electrons of Xe, Cs and Ba

Energy Technology Data Exchange (ETDEWEB)

Amusia, M Ya [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Cherepkov, N A [State University of Aerospace Instrumentation, St. Petersburg 190000 (Russian Federation); Chernysheva, L V [A F Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Felfli, Z [Department of Physics and Center for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta GA 30314 (United States); Msezane, A Z [Department of Physics and Center for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta GA 30314 (United States)

2005-04-28

The non-dipole contribution to spin polarization of photoelectrons from Xe, Cs and Ba 3d{sub 5/2} and 3d{sub 3/2} levels is calculated. The calculation is carried out within the framework of a modified version of the spin-polarized random phase approximation with exchange. The effects of relaxation of excited electrons due to the 3d-vacancy creation are also accounted for. It is demonstrated that the parameters that characterize the photoelectron angular distribution as functions of the incoming photon energy, although being predictably small, acquire additional peculiarities when the interaction between electrons that belong to the 3d{sub 5/2} and 3d{sub 3/2} components of the spin-orbit doublet is taken into account.

Resonant structure of the 3d electron's angular distribution in a free Mn+Ion

International Nuclear Information System (INIS)

Amusia, M.Y.; Dolmatov, V.K.

1995-01-01

The 3d-electron angular anisotropy parameter of the free Mn + ion is calculated using the open-quotes spin-polarizedclose quotes random-phase approximation with exchange. Strong resonance structure is discovered, which is due to interference with the powerful 3p → 3d discrete excitation. The effect of the 3p → 4s transition is also noticeable. The ordering of these respective resonances with phonon energy increase proved to be opposite in angular anisotropy parameter to that in 3d-photoionization cross section. A paper describing these results was published

Electron impact excitation of complex atoms and ions. Pt. 2: forbidden transitions in Ni+

International Nuclear Information System (INIS)

Watts, M.S.T.; Berrington, K.A.; Burke, P.G.

1996-01-01

This letter reports the first application of the new R-matrix program package RMATRX II to electron impact excitation of a near neutral open d-shell ion. In this calculation for Ni + , all states corresponding to the configuration 3d 9 , 3d 8 4s and 3d 8 4p have been included in the expansion of the total wavefunction. Thermally averaged collision strengths for forbidden transitions involving the even parity states are presented in tabular form for temperatures between 5000 K and 20 000 K. The importance of including accurate C1 expansions for both the target and the (N + 1)-electron terms is demonstrated. (Author)

FDM 3D printed coffee glove embedded with flexible electronic

KAUST Repository

Bahri, Meznan

2017-10-31

With the advances in 3D printing technology, Flexible Electronics can now be exploited to form the so-called “Embedded Electronics”. This paper describes experiences learned from a research project which ran during summer 2016 at KAUST, in collaboration with the Electrical and Computer Engineering Department at Effat University, and aimed at creating a heating coffee glove product operating on double alkaline batteries using Kapton© as a flexible substrate for the circuit. The circuit and its batteries are encapsulated in a 3D printed glove, designed using SolidWorks©. The proposed methodology and techniques applied during this work could be further used in implementing other technologies, such as thermoelectric coolers head patches, smart garments, and flexible smartphones. Limitation and recommendation of the present methodology are also discussed.

A new approach for 3D reconstruction from bright field TEM imaging: Beam precession assisted electron tomography

International Nuclear Information System (INIS)

Rebled, J.M.; Yedra, Ll.; Estrade, S.; Portillo, J.; Peiro, F.

2011-01-01

The successful combination of electron beam precession and bright field electron tomography for 3D reconstruction is reported. Beam precession is demonstrated to be a powerful technique to reduce the contrast artifacts due to diffraction and curvature in thin foils. Taking advantage of these benefits, Precession assisted electron tomography has been applied to reconstruct the morphology of Sn precipitates embedded in an Al matrix, from a tilt series acquired in a range from +49 o to -61 o at intervals of 2 o and with a precession angle of 0.6 o in bright field mode. The combination of electron tomography and beam precession in conventional TEM mode is proposed as an alternative procedure to obtain 3D reconstructions of nano-objects without a scanning system or a high angle annular dark field detector. -- Highlights: → Electron beam precession reduces spurious diffraction contrast in bright field mode. → Bend contour related contrast depends on precession angle. → Electron beam precession is combined with bright field electron tomography. → Precession assisted BF tomography allowed 3D reconstruction of a Sn precipitate.

An electron spin resonance study on the gamma-irradiation of urea, urea- d4, 1-3-dimethylurea, 1-3-diethylurea and 1,1',3,3'-tetramthylurea

International Nuclear Information System (INIS)

Kang, Y.S.; McManus, H.J.D.; Kevan, L.

1994-01-01

Urea, urea-d 4 , 1,3-dimethylurea, 1,3-diethylurea powder and 1,1',3,3'-tetramethylurea, and their solutions in D 2 O were γ-irradiated with 0.0882 kGy both at room temperature and at 77 K. The product radicals were identified with X-band electron spin resonance, based on the g-factor and hyperfine coupling constants. The radicals formed from urea and urea-d 4 were identified as nitrogen-centered and resulted from N-H bond dissociation. The radicals produced from 1,3-dimethylurea, 1,3-diethylurea and 1,1',3,3'-tetramethylurea were identified as carbon-centered and resulted from C-H bond cleavage. The electron spin resonance signals of 1,3-dimethylurea, 1,3-diethylurea and 1,1',3,3'-tetramethylurea are similar in both the powder and D 2 O solution. The radicals observed from 1,3-dimethylurea, 1,3-diethylurea and 1,1',3,3'-tetramethylurea were identified as . NH-CH 2 , . NH-CHCH 3 and . (CH 3 )(CH 2 ), respectively. (author)

3DSEM: A 3D microscopy dataset

Directory of Open Access Journals (Sweden)

Ahmad P. Tafti

2016-03-01

Full Text Available The Scanning Electron Microscope (SEM as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples. Keywords: 3D microscopy dataset, 3D microscopy vision, 3D SEM surface reconstruction, Scanning Electron Microscope (SEM

Detection of radiation transitions between 4d9(D5/3,3/2)5s2nl and 4d105p(2P1/2,3/20)nl of self-ionized states of cadmium atom at electron-ion collisions

International Nuclear Information System (INIS)

Gomonaj, A.N.; Imre, A.I.

2005-01-01

Radiation transitions between 4d 9 ( 2 D 5/2,3/2 )5s 2 nl and 4d 10 5p( 2 P 1/2,3/2 0 )nl self-ionized states of Cd atom being dielectron satellites of λ325.0 nm (4d 9 5s 22 D 3/2 →4d 10 5p 2 P 1/2 0 ) and λ353.6 nm (4d 9 5s 22 D 3/2 → 4d 10 5p 2 P 3/2 0 ) laser lines of Cd + ion were detected for the first time at electron-ion collisions. One studied energy dependences of the effective cross sections of electron excitation of the satellite lines within 7-10 eV energy range. The effective cross sections of excitation of dielectron satellites constitutes ∼ 10 -17 cm 2 that is comparable with the efficiency of excitation of the laser lines [ru

Incipient 2D Mott insulators in extreme high electron density, ultra-thin GdTiO3/SrTiO3/GdTiO3 quantum wells

Science.gov (United States)

Allen, S. James; Ouellette, Daniel G.; Moetakef, Pouya; Cain, Tyler; Chen, Ru; Balents, Leon; Stemmer, Susanne

2013-03-01

By reducing the number of SrO planes in a GdTiO3 /SrTiO3/ GdTiO3 quantum well heterostructure, an electron gas with ~ fixed 2D electron density can be driven close to the Mott metal insulator transition - a quantum critical point at ~1 electron per unit cell. A single interface between the Mott insulator GdTiO3 and band insulator SrTiO3 has been shown to introduce ~ 1/2 electron per interface unit cell. Two interfaces produce a quantum well with ~ 7 1014 cm-2 electrons: at the limit of a single SrO layer it may produce a 2D magnetic Mott insulator. We use temperature and frequency dependent (DC - 3eV) conductivity and temperature dependent magneto-transport to understand the relative importance of electron-electron interactions, electron-phonon interactions, and surface roughness scattering as the electron gas is compressed toward the quantum critical point. Terahertz time-domain and FTIR spectroscopies, measure the frequency dependent carrier mass and scattering rate, and the mid-IR polaron absorption as a function of quantum well thickness. At the extreme limit of a single SrO plane, we observe insulating behavior with an optical gap substantially less than that of the surrounding GdTiO3, suggesting a novel 2D Mott insulator. MURI program of the Army Research Office - Grant No. W911-NF-09-1-0398

Toward 3D structural information from quantitative electron exit wave analysis

International Nuclear Information System (INIS)

Borisenko, Konstantin B; Moldovan, Grigore; Kirkland, Angus I; Wang, Amy; Van Dyck, Dirk; Chen, Fu-Rong

2012-01-01

Simulations show that using a new direct imaging detector and accurate exit wave restoration algorithms allows nearly quantitative restoration of electron exit wave phase, which can be regarded as only qualitative for conventional indirect imaging cameras. This opens up a possibility of extracting accurate information on 3D atomic structure of the sample even from a single projection.

Electron impact ionization mass spectra of 3-substituted-2-hydroxy-4(3H)-quinazolinones

International Nuclear Information System (INIS)

El Deen, I. M.; Abd El Fattah, M. E.

2003-01-01

2-Amino-2-hydroxy-4(3H)-quinazolinone (3) was prepared via condensation of 1 with hydrazine hydrate. Treatment of 3 with appropriate acid in POCl 3 , ethyl chloroacetate and activated olefinic compounds in DMF yielded the corresponding 3-(substituted)amino-2-hydroxy-4(3H)-quinazolinones 4,5 and 6. The electron impact ionization mass spectra of compounds 3 and 4 show a weak molecular ion peak and a base peak of m/z 146 resulting from a cleavage fragmentation. The compounds 5 and 6 give a characteristics fragmentation pattern with a very stable fragment of benzopyrazolone (m/z 132)

Direct-write/cure conductive polymer nanocomposites for 3D structural electronics

Energy Technology Data Exchange (ETDEWEB)

Lu, Yanfeng; Vatani, Morteza; Choi, Jae Won [The University of Akron, Akron, Ohio (United States)

2013-10-15

The use of direct-write (DW) in the fabrication of conductive structures offers dramatic benefits over traditional technologies in terms of low-cost, print-on-demand conformal manufacturing. This DW process can be combined with direct-cure (DC) process as one-step manufacturing of conducting elements, whereas conventional methods need a manufacturing process of conducting elements followed by a relatively long time post-curing/baking process. A hybrid technology combined with direct-write/cure (DWC) and projection microstereolithography (PμSL) is presented in this work. Carbon nanotubes (CNTs) were dispersed in a photopolymer solution to introduce conductivity. The developed PμSL was used to create 3D structures, and DWC of conductive photopolymers with CNTs was utilized to produce conductive paths. To show the capabilities of the developed system and materials, a 3D structure with embedded conductive paths was designed and fabricated. Based on the experiments, it is thought that the suggested manufacturing process and materials are promising to produce 3D structural electronics.

Direct-write/cure conductive polymer nanocomposites for 3D structural electronics

International Nuclear Information System (INIS)

Lu, Yanfeng; Vatani, Morteza; Choi, Jae Won

2013-01-01

The use of direct-write (DW) in the fabrication of conductive structures offers dramatic benefits over traditional technologies in terms of low-cost, print-on-demand conformal manufacturing. This DW process can be combined with direct-cure (DC) process as one-step manufacturing of conducting elements, whereas conventional methods need a manufacturing process of conducting elements followed by a relatively long time post-curing/baking process. A hybrid technology combined with direct-write/cure (DWC) and projection microstereolithography (PμSL) is presented in this work. Carbon nanotubes (CNTs) were dispersed in a photopolymer solution to introduce conductivity. The developed PμSL was used to create 3D structures, and DWC of conductive photopolymers with CNTs was utilized to produce conductive paths. To show the capabilities of the developed system and materials, a 3D structure with embedded conductive paths was designed and fabricated. Based on the experiments, it is thought that the suggested manufacturing process and materials are promising to produce 3D structural electronics.

Formation of heavy d-electron quasiparticles in Sr3Ru2O7

International Nuclear Information System (INIS)

Allan, M P; Tamai, A; Rozbicki, E; King, P D C; Meevasana, W; Perry, R S; Mercure, J F; Mackenzie, A P; Fischer, M H; Wang, M A; Lee, Jinho; Kim, E-A; Lawler, M J; Shen, K M; Voss, J; Fennie, C J; Thirupathaiah, S; Rienks, E; Fink, J; Tennant, D A

2013-01-01

The phase diagram of Sr 3 Ru 2 O 7 shows hallmarks of strong electron correlations despite the modest Coulomb interaction in the Ru 4d shell. We use angle-resolved photoelectron spectroscopy measurements to provide microscopic insight into the formation of the strongly renormalized heavy d-electron liquid that controls the physics of Sr 3 Ru 2 O 7 . Our data reveal itinerant Ru 4d-states confined over large parts of the Brillouin zone to an energy range of <6 meV, nearly three orders of magnitude lower than the bare band width. We show that this energy scale agrees quantitatively with a characteristic thermodynamic energy scale associated with quantum criticality and illustrate how it arises from a combination of back-folding due to a structural distortion and the hybridization of light and strongly renormalized, heavy quasiparticle bands. The resulting heavy Fermi liquid has a marked k-dependence of the renormalization which we relate to orbital mixing along individual Fermi surface sheets. (paper)

3D Printing and Its Disruptive Impacts on Supply Chains of the Future

Directory of Open Access Journals (Sweden)

Sebastian Mohr

2015-11-01

Full Text Available 3D printing technology has emerged as one of the most disruptive innovations to impact the global supply chain and logistics industry. The technology is impacting our personal and professional lives, with some claiming that the technology will revolutionize and replace existing manufacturing technologies, while others argue that the technology merely enhances some aspects of the production process. Whether evolutionary or revolutionary, 3D printing technology is recognized as a striking trend that will significantly impact supply chains. Although the expansion of 3D printing in the private consumer market is an interesting development in its own right, the biggest potential for disruption lies in industrial applications and how 3D printing will influence supply chains of the future. In this article, we examine the areas of the supply chain most likely to be disrupted by 3D printing technology and we identify the key questions that must be answered in a roadmap for future research and practice. While we seek answers to these questions, we suggest that managers should develop a flexible change management strategy to mitigate the effects of disruption to their future supply chains and take advantage of the resulting opportunities. Those that do nothing will be left wanting, because the influence of 3D printing technology on supply chains is expected to grow.

The impact of 3D and 2D TV watching on neurophysiological responses and cognitive functioning in adults.

Science.gov (United States)

Jeong, Hyun-Ghang; Ko, Young-Hoon; Han, Changsu; Oh, So-Young; Park, Kun Woo; Kim, Taehee; Ko, Deokwon

2015-12-01

Watching three-dimensional television (3D TV) may strain the eyes. However, other potential harmful effects of 3D TV watching have been rarely investigated. The current study examined the impact of 3D TV watching on neurophysiological responses and cognitive functioning as compared with two-dimensional TV (2D TV) watching. A total of 72 individuals were randomly assigned to either a 3D TV watching group or a 2D TV watching group. Electroencephalography (EEG) was used to measure neurophysiological responses, and computerized neurocognitive tests were conducted immediately before and after TV watching. The Simulator Sickness Questionnaire (SSQ) was used to assess visual discomfort. There was a significant change in visual discomfort between the two groups (SSQ score at baseline: 2.28 ± 3.05 for the 3D TV group and 3.69 ± 3.49 for the 2D TV group; SSQ score after watching TV: 4.6 ± 3.35 for the 3D TV group and 4.03 ± 3.47 for the 2D TV group), and this change was greater for the 3D TV watching group (P = 0.025). However, 3D TV watching did not have a differential impact on EEG responses. Furthermore, there were no significant differences between the groups in terms of changes in cognitive performance, except for a subtle difference in backward digit span performance. Our findings suggest that 3D TV watching is as safe as 2D TV watching in terms of neurophysiological responses and cognitive functioning. Potential harmful effects of TV viewing might be similar regardless of whether 3D or 2D TV is viewed. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Local 3d Electronic Structures of Co-Based Complexes with Medicinal Molecules Probed by Soft X-ray Absorption

Science.gov (United States)

Yamagami, Kohei; Fujiwara, Hidenori; Imada, Shin; Kadono, Toshiharu; Yamanaka, Keisuke; Muro, Takayuki; Tanaka, Arata; Itai, Takuma; Yoshinari, Nobuto; Konno, Takumi; Sekiyama, Akira

2017-07-01

We have examined the local 3d electronic structures of Co-Au multinuclear complexes with the medicinal molecules d-penicillaminate (d-pen) [Co{Au(PPh3)(d-pen)}2]ClO4 and [Co3{Au3(tdme)(d-pen)3}2] by Co L2,3-edge soft X-ray absorption (XAS) spectroscopy, where PPh3 denotes triphenylphosphine and tdme stands for 1,1,1-tris[(diphenylphosphino)methyl]ethane. The Co L2,3-edge XAS spectra indicate the localized ionic 3d electronic states in both materials. The experimental spectra are well explained by spectral simulation for a localized Co ion under ligand fields with the full multiplet theory, which verifies that the ions are in the low-spin Co3+ state in the former compound and in the high-spin Co2+ state in the latter.

Spatiotemporal Observation of Electron-Impact Dynamics in Photovoltaic Materials Using 4D Electron Microscopy

KAUST Repository

Shaheen, Basamat

2017-05-17

Understanding light-triggered charge carrier dynamics near photovoltaic-material surfaces and at interfaces has been a key element and one of the major challenges for the development of real-world energy devices. Visualization of such dynamics information can be obtained using the one-of-a-kind methodology of scanning ultrafast electron microscopy (S-UEM). Here, we address the fundamental issue of how the thickness of the absorber layer may significantly affect the charge carrier dynamics on material surfaces. Time-resolved snapshots indicate that the dynamics of charge carriers generated by electron impact in the electron-photon dynamical probing regime is highly sensitive to the thickness of the absorber layer, as demonstrated using CdSe films of different thicknesses as a model system. This finding not only provides the foundation for potential applications of S-UEM to a wide range of devices in the fields of chemical and materials research, but also has impact on the use and interpretation of electron beam-induced current for optimization of photoactive materials in these devices.

A new approach for 3D reconstruction from bright field TEM imaging: Beam precession assisted electron tomography

Energy Technology Data Exchange (ETDEWEB)

Rebled, J.M. [LENS-MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Institut de Ciencia de Materials de Barcelona-CSIC, Campus UAB, 08193 Bellaterra (Spain); Yedra, Ll. [LENS-MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Estrade, S.; Portillo, J. [LENS-MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); TEM-MAT, CCiT-UB, Sole i Sabaris 1, 08028 Barcelona (Spain); Peiro, F., E-mail: francesca.peiro@ub.edu [LENS-MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain)

2011-08-15

The successful combination of electron beam precession and bright field electron tomography for 3D reconstruction is reported. Beam precession is demonstrated to be a powerful technique to reduce the contrast artifacts due to diffraction and curvature in thin foils. Taking advantage of these benefits, Precession assisted electron tomography has been applied to reconstruct the morphology of Sn precipitates embedded in an Al matrix, from a tilt series acquired in a range from +49{sup o} to -61{sup o} at intervals of 2{sup o} and with a precession angle of 0.6{sup o} in bright field mode. The combination of electron tomography and beam precession in conventional TEM mode is proposed as an alternative procedure to obtain 3D reconstructions of nano-objects without a scanning system or a high angle annular dark field detector. -- Highlights: {yields} Electron beam precession reduces spurious diffraction contrast in bright field mode. {yields} Bend contour related contrast depends on precession angle. {yields} Electron beam precession is combined with bright field electron tomography. {yields} Precession assisted BF tomography allowed 3D reconstruction of a Sn precipitate.

Hybrid additive manufacturing of 3D electronic systems

International Nuclear Information System (INIS)

Li, J; Wasley, T; Nguyen, T T; Kay, R; Ta, V D; Shephard, J D; Stringer, J; Smith, P; Esenturk, E; Connaughton, C

2016-01-01

A novel hybrid additive manufacturing (AM) technology combining digital light projection (DLP) stereolithography (SL) with 3D micro-dispensing alongside conventional surface mount packaging is presented in this work. This technology overcomes the inherent limitations of individual AM processes and integrates seamlessly with conventional packaging processes to enable the deposition of multiple materials. This facilitates the creation of bespoke end-use products with complex 3D geometry and multi-layer embedded electronic systems. Through a combination of four-point probe measurement and non-contact focus variation microscopy, it was identified that there was no obvious adverse effect of DLP SL embedding process on the electrical conductivity of printed conductors. The resistivity maintained to be less than 4  ×  10 −4 Ω · cm before and after DLP SL embedding when cured at 100 °C for 1 h. The mechanical strength of SL specimens with thick polymerized layers was also identified through tensile testing. It was found that the polymerization thickness should be minimised (less than 2 mm) to maximise the bonding strength. As a demonstrator a polymer pyramid with embedded triple-layer 555 LED blinking circuitry was successfully fabricated to prove the technical viability. (paper)

Electron impact excitation cross sections and rates from the ground state of atomic calcium

CERN Document Server

Samson, A M

2001-01-01

New R-matrix calculations are presented for electron excitation of atomic calcium. The target state expansion includes 22 states: 4s sup 2 sup 1 S; 4snl sup 1 sup , sup 3 L, where nl is 3d, 4p, 5s, 5p, 4d and 4f; 3d4p sup 1 sup , sup 3 P,D,F; and 4p sup 2 sup 3 P, sup 1 D, sup 1 S terms. The calculation is in LS coupling, and configuration interaction involving 3p subshell correlation is included. Electron impact excitation cross sections from the 4s sup 2 ground state to the next 10 states are tabulated for low energies, and thermally averaged effective collision strengths are tabulated over a range of electron temperatures from 1000 to 10,000 K. Comparisons are made with previous cross sections calculations for the 4s sup 2 -4s4p sup 3 P deg. transition; excellent agreement is found with experimentally derived rates for 4s sup 2 -4s4p sup 1 P deg

Electron acceleration in the Solar corona - 3D PiC code simulations of guide field reconnection

Science.gov (United States)

Alejandro Munoz Sepulveda, Patricio

2017-04-01

The efficient electron acceleration in the solar corona detected by means of hard X-ray emission is still not well understood. Magnetic reconnection through current sheets is one of the proposed production mechanisms of non-thermal electrons in solar flares. Previous works in this direction were based mostly on test particle calculations or 2D fully-kinetic PiC simulations. We have now studied the consequences of self-generated current-aligned instabilities on the electron acceleration mechanisms by 3D magnetic reconnection. For this sake, we carried out 3D Particle-in-Cell (PiC) code numerical simulations of force free reconnecting current sheets, appropriate for the description of the solar coronal plasmas. We find an efficient electron energization, evidenced by the formation of a non-thermal power-law tail with a hard spectral index smaller than -2 in the electron energy distribution function. We discuss and compare the influence of the parallel electric field versus the curvature and gradient drifts in the guiding-center approximation on the overall acceleration, and their dependence on different plasma parameters.

Electronic structures and magnetic properties of 3d and 4d transition-metal impurities in ferromagnetic Fe

CERN Document Server

Park, J H; Min, B I; Cho, H S

2000-01-01

Employing the self-consistent local approach, the tight-binding linear-muffin-tin orbital recursion method, we have investigated the electronic structures and the magnetic properties of 3d and 4d transition-metal (TM) impurities in ferromagnetic bcc Fe. In both 3d and 4d TM impurities, virtual bound states appear and are characterized by a high density of states in the energy spectrum. The characters of the states are studied by calculating the bond order between interaction orbitals. For early TM impurities, the states at the impurity sites have more antibonding characters, while the states at neighboring Fe sites have more bonding characters. For late TM impurities, the situation is reversed. late TM impurities of both the 3d and the 4d TM series have the same magnetic ordering as the host Fe atoms whereas early TM impurities have magnetic moments antiparallel to that of the host. As for the Mn impurity, an inward relaxation of neighboring Fe atoms stabilizes the antiferromagnetic ordering with respect to t...

Front-end receiver electronics for a matrix transducer for 3-D transesophageal echocardiography.

Science.gov (United States)

Yu, Zili; Blaak, Sandra; Chang, Zu-yao; Yao, Jiajian; Bosch, Johan G; Prins, Christian; Lancée, Charles T; de Jong, Nico; Pertijs, Michiel A P; Meijer, Gerard C M

2012-07-01

There is a clear clinical need for creating 3-D images of the heart. One promising technique is the use of transesophageal echocardiography (TEE). To enable 3-D TEE, we are developing a miniature ultrasound probe containing a matrix piezoelectric transducer with more than 2000 elements. Because a gastroscopic tube cannot accommodate the cables needed to connect all transducer elements directly to an imaging system, a major challenge is to locally reduce the number of channels, while maintaining a sufficient signal-to-noise ratio. This can be achieved by using front-end receiver electronics bonded to the transducers to provide appropriate signal conditioning in the tip of the probe. This paper presents the design of such electronics, realizing time-gain compensation (TGC) and micro-beamforming using simple, low-power circuits. Prototypes of TGC amplifiers and micro-beamforming cells have been fabricated in 0.35-μm CMOS technology. These prototype chips have been combined on a printed circuit board (PCB) to form an ultrasound-receiver system capable of reading and combining the signals of three transducer elements. Experimental results show that this design is a suitable candidate for 3-D TEE.

Model-based Adjustment of Droplet Characteristic for 3D Electronic Printing

Directory of Open Access Journals (Sweden)

Lin Na

2017-01-01

Full Text Available The major challenge in 3D electronic printing is the print resolution and accuracy. In this paper, a typical mode - lumped element modeling method (LEM - is adopted to simulate the droplet jetting characteristic. This modeling method can quickly get the droplet velocity and volume with a high accuracy. Experimental results show that LEM has a simpler structure with the sufficient simulation and prediction accuracy.

Electronic structures and photophysics of d8-d8 complexes

Czech Academy of Sciences Publication Activity Database

Gray, H. B.; Záliš, Stanislav; Vlček, Antonín

2017-01-01

Roč. 345, AUG 2017 (2017), s. 297-317 ISSN 0010-8545 R&D Projects: GA MŠk LH13015 Grant - others:COST(XE) CM1405 Institutional support: RVO:61388955 Keywords : excitation * electronic structures * photophysics Subject RIV: CG - Electrochemistry OBOR OECD: Physical chemistry Impact factor: 13.324, year: 2016

Towards 3D crystal orientation reconstruction using automated crystal orientation mapping transmission electron microscopy (ACOM-TEM).

Science.gov (United States)

Kobler, Aaron; Kübel, Christian

2018-01-01

To relate the internal structure of a volume (crystallite and phase boundaries) to properties (electrical, magnetic, mechanical, thermal), a full 3D reconstruction in combination with in situ testing is desirable. In situ testing allows the crystallographic changes in a material to be followed by tracking and comparing the individual crystals and phases. Standard transmission electron microscopy (TEM) delivers a projection image through the 3D volume of an electron-transparent TEM sample lamella. Only with the help of a dedicated TEM tomography sample holder is an accurate 3D reconstruction of the TEM lamella currently possible. 2D crystal orientation mapping has become a standard method for crystal orientation and phase determination while 3D crystal orientation mapping have been reported only a few times. The combination of in situ testing with 3D crystal orientation mapping remains a challenge in terms of stability and accuracy. Here, we outline a method to 3D reconstruct the crystal orientation from a superimposed diffraction pattern of overlapping crystals without sample tilt. Avoiding the typically required tilt series for 3D reconstruction enables not only faster in situ tests but also opens the possibility for more stable and more accurate in situ mechanical testing. The approach laid out here should serve as an inspiration for further research and does not make a claim to be complete.

3D detector and electronics integration technologies: Applications to ILC, SLHC, and beyond

International Nuclear Information System (INIS)

Lipton, Ronald

2011-01-01

The application of vertically integrated (3D) electronics to particle physics has been explored by the our group for the past several years. We have successfully designed the first vertically integrated demonstrator chip for ILC vertex detection in the three-tier MIT-Lincoln Labs process. We have also studied sensor integration with electronics through oxide bonding and silicon-on-insulator technology. This paper will discuss the status of these studies and prospects for future work.

3D detector and electronics integration technologies: Applications to ILC, SLHC, and beyond

Energy Technology Data Exchange (ETDEWEB)

Lipton, Ronald, E-mail: lipton@fnal.gov [Fermilab, P.O. Box 500, Batavia, IL 60510 (United States)

2011-04-21

The application of vertically integrated (3D) electronics to particle physics has been explored by the our group for the past several years. We have successfully designed the first vertically integrated demonstrator chip for ILC vertex detection in the three-tier MIT-Lincoln Labs process. We have also studied sensor integration with electronics through oxide bonding and silicon-on-insulator technology. This paper will discuss the status of these studies and prospects for future work.

Make or Buy: An Analysis of the Impacts of 3D Printing Operations, 3D Laser Scanning Technology, and Collaborative Product Lifecycle Management on Ship Maintenance and Modernization Cost Savings

Science.gov (United States)

2015-03-21

Policy - 37 - Naval Postgraduate School the number of brazes and welds from 25 to just five. There are currently more than 300 3D printing ...NPS-LM-15-002 ACQUISITION RESEARCH PROGRAM SPONSORED REPORT SERIES Make or Buy: An Analysis of the Impacts of 3D Printing Operations, 3D ...Program Sponsored Report Series Make or Buy: An Analysis of the Impacts of 3D Printing Operations, 3D Laser Scanning Technology, and Collaborative

Tunable Electron-Electron Interactions in LaAlO_{3}/SrTiO_{3} Nanostructures

Directory of Open Access Journals (Sweden)

Guanglei Cheng

2016-12-01

Full Text Available The interface between the two complex oxides LaAlO_{3} and SrTiO_{3} has remarkable properties that can be locally reconfigured between conducting and insulating states using a conductive atomic force microscope. Prior investigations of “sketched” quantum dot devices revealed a phase in which electrons form pairs, implying a strongly attractive electron-electron interaction. Here, we show that these devices with strong electron-electron interactions can exhibit a gate-tunable transition from a pair-tunneling regime to a single-electron (Andreev bound state tunneling regime where the interactions become repulsive. The electron-electron interaction sign change is associated with a Lifshitz transition where the d_{xz} and d_{yz} bands start to become occupied. This electronically tunable electron-electron interaction, combined with the nanoscale reconfigurability of this system, provides an interesting starting point towards solid-state quantum simulation.

Dynamic scattering theory for dark-field electron holography of 3D strain fields.

Science.gov (United States)

Lubk, Axel; Javon, Elsa; Cherkashin, Nikolay; Reboh, Shay; Gatel, Christophe; Hÿtch, Martin

2014-01-01

Dark-field electron holography maps strain in crystal lattices into reconstructed phases over large fields of view. Here we investigate the details of the lattice strain-reconstructed phase relationship by applying dynamic scattering theory both analytically and numerically. We develop efficient analytic linear projection rules for 3D strain fields, facilitating a straight-forward calculation of reconstructed phases from 3D strained materials. They are used in the following to quantify the influence of various experimental parameters like strain magnitude, specimen thickness, excitation error and surface relaxation. © 2013 Elsevier B.V. All rights reserved.

3D imaging by serial block face scanning electron microscopy for materials science using ultramicrotomy

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, Teruo, E-mail: t.hashimoto@manchester.ac.uk; Thompson, George E.; Zhou, Xiaorong; Withers, Philip J.

2016-04-15

Mechanical serial block face scanning electron microscopy (SBFSEM) has emerged as a means of obtaining three dimensional (3D) electron images over volumes much larger than possible by focused ion beam (FIB) serial sectioning and at higher spatial resolution than achievable with conventional X-ray computed tomography (CT). Such high resolution 3D electron images can be employed for precisely determining the shape, volume fraction, distribution and connectivity of important microstructural features. While soft (fixed or frozen) biological samples are particularly well suited for nanoscale sectioning using an ultramicrotome, the technique can also produce excellent 3D images at electron microscope resolution in a time and resource-efficient manner for engineering materials. Currently, a lack of appreciation of the capabilities of ultramicrotomy and the operational challenges associated with minimising artefacts for different materials is limiting its wider application to engineering materials. Consequently, this paper outlines the current state of the art for SBFSEM examining in detail how damage is introduced during slicing and highlighting strategies for minimising such damage. A particular focus of the study is the acquisition of 3D images for a variety of metallic and coated systems. - Highlights: • The roughness of the ultramicrotomed block face of AA2024 in Al area was 1.2 nm. • Surface texture associated with chattering was evident in grains with 45° diamond knife. • A 76° rake angle minimises the stress on the block face. • Using the oscillating knife with a cutting speed of 0.04 mms{sup −1} minimised the surface texture. • A variety of material applications were presented.

3D-finite element impact simulation on concrete structures

Energy Technology Data Exchange (ETDEWEB)

Heider, N.

1989-12-15

The analysis of impact processes is an interesting application of full 3D Finite Element calculations. This work presents a simulation of the penetration process of a Kinetic Energy projectile into a concrete target. Such a calculation requires an adequate FE model, especially a proper description of the crack opening process in front of the projectile. The aim is the prediction of the structural survival of the penetrator case with the help of an appropriate failure criterion. Also, the computer simulation allows a detailed analysis of the physical phenomena during impact. (orig.) With 4 refs., 14 figs.

Programming 2D/3D shape-shifting with hobbyist 3D printers† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7mh00269f

Science.gov (United States)

van Manen, Teunis; Janbaz, Shahram

2017-01-01

Materials and devices with advanced functionalities often need to combine complex 3D shapes with functionality-inducing surface features. Precisely controlled bio-nanopatterns, printed electronic components, and sensors/actuators are all examples of such surface features. However, the vast majority of the refined technologies that are currently available for creating functional surface features work only on flat surfaces. Here we present initially flat constructs that upon triggering by high temperatures change their shape to a pre-programmed 3D shape, thereby enabling the combination of surface-related functionalities with complex 3D shapes. A number of shape-shifting materials have been proposed during the last few years based on various types of advanced technologies. The proposed techniques often require multiple fabrication steps and special materials, while being limited in terms of the 3D shapes they could achieve. The approach presented here is a single-step printing process that requires only a hobbyist 3D printer and inexpensive off-the-shelf materials. It also lends itself to a host of design strategies based on self-folding origami, instability-driven pop-up, and ‘sequential’ shape-shifting to unprecedentedly expand the space of achievable 3D shapes. This combination of simplicity and versatility is a key to widespread applications. PMID:29308207

The role and impact of 3D printing technologies in casting

Directory of Open Access Journals (Sweden)

Jin-wu Kang

2017-05-01

Full Text Available 3D printing is such a magical technology that it extends into almost every sector relating to manufacturing, not to mention casting production. In this paper, the past, present and future of 3D printing in the foundry sector are profoundly reviewed. 3D printing has the potential to supplement or partially replace the casting method. Today, some castings can be directly printed by metal powders, for example, titanium alloys, nickel alloys and steel parts. Meanwhile, 3D printing has found an unique position in other casting aspects as well, such as printing the wax pattern, ceramic shell, sand core, sand mould, etc. Most importantly, 3D printing is not just a manufacturing method, it will also revolutionize the design of products, assemblies and parts, such as castings, patterns, cores, moulds and shells in casting production. The solid structure of castings and moulds will be redesigned in future into truss or spatially open and skeleton structures. This kind of revolution is just sprouting, but it will bring unimaginable impact on manufacturing including casting production. Nobody doubts the potential of 3D printing technologies in manufacturing, but they do have limitations and drawbacks.

Electron excitation cross sections for some Ar I 5d (J = 2) levels

International Nuclear Information System (INIS)

Blanco, F.; Sanchez, J.A.; Campos, J.

1992-01-01

Absolute excitation cross sections by electron impact for some 5d levels with J = 2 of Ar I have been measured by the optical method. Excitation functions for electron energies in the range from the excitation threshold to 1000 eV are also reported. A delayed coincidence analysis of the de-excitation at 100 eV electron energy allowed for the subtraction of radiative cascades. The resulting excitation cross sections are between 7.3 and 12x10 -20 cm 2 . (author)

A detailed study of FDIRC prototype with waveform digitizing electronics in cosmic ray telescope using 3D tracks

Science.gov (United States)

Nishimura, K.; Dey, B.; Aston, D.; Leith, D. W. G. S.; Ratcliff, B.; Roberts, D.; Ruckman, L.; Shtol, D.; Varner, G. S.; Va'vra, J.

2013-02-01

We present a detailed study of a novel Cherenkov imaging detector called the Focusing DIRC (FDIRC) with waveform digitizing electronics. In this study, the FDIRC prototype has been instrumented with seven Hamamatsu H-8500 MaPMTs. Waveforms from 384 pixels are digitized with waveform sampling electronics based on the BLAB2 ASIC, operating at a sampling speed of ∼2.5 GSa/s. The FDIRC prototype was tested in a large cosmic ray telescope (CRT) providing 3D muon tracks with ∼1.5 mrad angular resolution and muon energy of Emuon> 1.6 GeV. In this study we provide a detailed analysis of the tails in the Cherenkov angle distribution as a function of various variables, compare experimental results with simulation, and identify the major contributions to the tails. We demonstrate that to see the full impact of these tails on the Cherenkov angle resolution, it is crucial to use 3D tracks, and have a full understanding of the role of reconstruction ambiguities. These issues could not be fully explored in previous FDIRC studies where the beam was perpendicular to the quartz radiator bars. This work is relevant for the final FDIRC prototype of the PID detector at SuperB, which will be tested this year in the CRT setup.

A Detailed Study of FDIRC Prototype with Waveform Digitizing Electronics in Cosmic Ray Telescope Using 3D Tracks

International Nuclear Information System (INIS)

Nishimura, K.; Dey, B.; Aston, D.; Leith, D.W.G.S.; Ratcliff, B.; Roberts, D.; Ruckman, L.; Shtol, D.; Varner, G.S.; Va'vra, J.

2012-01-01

We present a detailed study of a novel Cherenkov imaging detector called the Focusing DIRC (FDIRC) with waveform digitizing electronics. In this test study, the FDIRC prototype has been instrumented with seven Hamamatsu H-8500 MaPMTs. Waveforms from ∼450 pixels are digitized with waveform sampling electronics based on the BLAB2 ASIC, operating at a sampling speed of ∼2.5 GSa/s. The FDIRC prototype was tested in a large cosmic ray telescope (CRT) providing 3D muon tracks with ∼1.5 mrad angular resolution and muon energy of E muon > 1.6 GeV. In this study we provide a detailed analysis of the tails in the Cherenkov angle distribution as a function of various variables, compare experimental results with simulation, and identify the major contributions to the tails. We demonstrate that to see the full impact of these tails on the Cherenkov angle resolution, it is crucial to use 3D tracks, and have a full understanding of the role of ambiguities. These issues could not be fully explored in previous FDIRC studies where the beam was perpendicular to the quartz radiator bars. This work is relevant for the final FDIRC prototype of the PID detector at SuperB, which will be tested this year in the CRT setup.

Freezing hot electrons. Electron transfer and solvation dynamics at D{sub 2}O and NH{sub 3}-metal interfaces

Energy Technology Data Exchange (ETDEWEB)

Staehler, A.J.

2007-05-15

The present work investigates the electron transfer and solvation dynamics at the D{sub 2}O/Cu(111), D{sub 2}O/Ru(001), and NH{sub 3}/Cu(111) interfaces using femtosecond time-resolved two-photon photoelectron spectroscopy. Within this framework, the influence of the substrate, adsorbate structure and morphology, solvation site, coverage, temperature, and solvent on the electron dynamics are studied, yielding microscopic insight into the underlying fundamental processes. Transitions between different regimes of ET, substrate-dominated, barrier-determined, strong, and weak coupling are observed by systematic variation of the interfacial properties and development of empirical model descriptions. It is shown that the fundamental steps of the interfacial electron dynamics are similar for all investigated systems: Metal electrons are photoexcited to unoccupied metal states and transferred into the adlayer via the adsorbate's conduction band. The electrons localize at favorable sites and are stabilized by reorientations of the surrounding polar solvent molecules. Concurrently, they decay back two the metal substrate, as it offers a continuum of unoccupied states. However, the detailed characteristics vary for the different investigated interfaces: For amorphous ice-metal interfaces, the electron transfer is initially, right after photoinjection, dominated by the substrate's electronic surface band structure. With increasing solvation, a transient barrier evolves at the interface that increasingly screens the electrons from the substrate. Tunneling through this barrier becomes the rate-limiting step for ET. The competition of electron decay and solvation leads to lifetimes of the solvated electrons in the order of 100 fs. Furthermore, it is shown that the electrons bind in the bulk of the ice layers, but on the edges of adsorbed D{sub 2}O clusters and that the ice morphology strongly influences the electron dynamics. For the amorphous NH{sub 3}/Cu(111

Virtual rough samples to test 3D nanometer-scale scanning electron microscopy stereo photogrammetry.

Science.gov (United States)

Villarrubia, J S; Tondare, V N; Vladár, A E

2016-01-01

The combination of scanning electron microscopy for high spatial resolution, images from multiple angles to provide 3D information, and commercially available stereo photogrammetry software for 3D reconstruction offers promise for nanometer-scale dimensional metrology in 3D. A method is described to test 3D photogrammetry software by the use of virtual samples-mathematical samples from which simulated images are made for use as inputs to the software under test. The virtual sample is constructed by wrapping a rough skin with any desired power spectral density around a smooth near-trapezoidal line with rounded top corners. Reconstruction is performed with images simulated from different angular viewpoints. The software's reconstructed 3D model is then compared to the known geometry of the virtual sample. Three commercial photogrammetry software packages were tested. Two of them produced results for line height and width that were within close to 1 nm of the correct values. All of the packages exhibited some difficulty in reconstructing details of the surface roughness.

Self-Consistent 3D Modeling of Electron Cloud Dynamics and Beam Response

International Nuclear Information System (INIS)

Furman, Miguel; Furman, M.A.; Celata, C.M.; Kireeff-Covo, M.; Sonnad, K.G.; Vay, J.-L.; Venturini, M.; Cohen, R.; Friedman, A.; Grote, D.; Molvik, A.; Stoltz, P.

2007-01-01

We present recent advances in the modeling of beam electron-cloud dynamics, including surface effects such as secondary electron emission, gas desorption, etc, and volumetric effects such as ionization of residual gas and charge-exchange reactions. Simulations for the HCX facility with the code WARP/POSINST will be described and their validity demonstrated by benchmarks against measurements. The code models a wide range of physical processes and uses a number of novel techniques, including a large-timestep electron mover that smoothly interpolates between direct orbit calculation and guiding-center drift equations, and a new computational technique, based on a Lorentz transformation to a moving frame, that allows the cost of a fully 3D simulation to be reduced to that of a quasi-static approximation

The 3d8-(3d74p + 3p53d9) transitions in Br X: A striking case of configuration interaction

International Nuclear Information System (INIS)

Kleef, T.A.M. van; Uylings, P.H.M.; Ryabtsev, A.N.; Podobedova, L.I.; Joshi, Y.N.

1988-01-01

The spectrum of nine times ionized bromine (Br X) was photographed in the 90-120 A wavelength region on a variety of grazing incidence spectrographs using an open spark and a triggered spark as light sources. The analysis of the 3d 8 -(3d 7 4p + 3p 5 3d 9 ) transitions has resulted in establishing all 9 levels of the 3d 8 configuration, all 12 levels of the 3p 5 3d 9 configuration and 99 out of 110 levels of the 3d 7 4p configuration. The excitation probability of the 3p inner-shell electron increases with nuclear charge and in Br X is comparable with the excitation probability of the optical electrons resulting in a very strong configuration interaction between the 3p 5 3d 9 and 3d 7 4p configurations. Parametric calculations treating these configurations as one super configuration support the analysis. Two hundred and thirty two lines have been classified in this spectrum. (orig.)

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.

Do-It-Yourself: 3D Models of Hydrogenic Orbitals through 3D Printing

Science.gov (United States)

Griffith, Kaitlyn M.; de Cataldo, Riccardo; Fogarty, Keir H.

2016-01-01

Introductory chemistry students often have difficulty visualizing the 3-dimensional shapes of the hydrogenic electron orbitals without the aid of physical 3D models. Unfortunately, commercially available models can be quite expensive. 3D printing offers a solution for producing models of hydrogenic orbitals. 3D printing technology is widely…

Electron impact excitation of fine-structure levels of neon-like titanium (Ti XIII)

International Nuclear Information System (INIS)

Gupta, G.P.; Deb, N.C.; Msezane, A.Z.

1999-01-01

The authors present results of a Breit-Pauli R-matrix calculation for the electron impact excitation of neon-like titanium, in which the 27 lowest fine-structure target levels arising out of the 4 lowest configurations 2s 2 2p 6 , 2s 2 2p 5 3s, 2s 2 2p 5 3p, and 2s 2 2p 5 3d are included. These target levels are represented by configuration interaction wave functions using the 1s, 2s, 2p, 3s, 3p, and 3d basic orbitals. The relativistic effects are included in the Breit-Pauli approximation via one-body mass correction, Darwin, and spin-orbit interaction terms in the scattering equations. For many transitions, complex resonance structures are found in the excitation cross sections. The excitation cross sections are integrated over a Maxwellian distribution of electron energies to give electron excitation rate coefficients over a wide temperature range from 150 to 600 eV. The relative populations for different electron densities and temperatures are also presented

Electron-impact ionization of SiCl{sub 3} using an improved crossed fast-neutral-beam - electron-beam apparatus

Energy Technology Data Exchange (ETDEWEB)

Mahoney, J M; Gutkin, M V; Tarnovsky, V; Becker, K [Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)], E-mail: kbecker@poly.edu

2008-05-15

The fast-neutral-beam technique is a versatile approach to the determination of absolute cross sections for electron-impact ionization of atoms, stable molecules as well as free radicals and metastable species. A fast neutral beam of the species under study is prepared by charge-transfer neutralization of a mass-selected ion beam and the species are subsequently ionized by an electron beam. Mass- and energy-dispersive selection separates singly from multiply charged ions and parent from fragment ions and allows the determination of partial ionization cross sections. Here we describe some major improvements that were made recently to the fast-beam apparatus that has been used extensively for ionization cross section measurements for the past 15 years in our group. Experiments using well-established ionization cross sections in conjunction with extensive ion trajectory simulations were carried out to test the satisfactory performance of the modified fast-neutral-beam apparatus. We also report absolute partial cross sections for the formation of various singly charged positive ions produced by electron impact on SiCl{sub 3} for impact energies from threshold to 200 eV in the modified fast-beam apparatus.

Cascade production of Ar(3p54p) following electron bombardment

International Nuclear Information System (INIS)

Keto, J.W.; Kuo, C.

1981-01-01

We observe the time dependence of the fluorescence of Ar(3p 5 4p) following electron excitation of argon at pressures from 2--3000 Torr. The population of these levels at the lowest pressures observed is dominated by radiative cascade from Ar(3p 5 3d) and Ar(3p 5 5s). For argon states 4p'[1/2] 0 , 4p'[3/2] 2 , and 4p[1/2] 0 we find the cascade transitions can be identified and we assign radiative lifetimes of 61 +- 10, 69 +- 12, and 61 +- 6 nsec to 3d'[3/2] 1 , 3d'[5/2] 3 , and 3d[3/2] 1 , respectively. For cascade lifetimes to other levels, unique assignments cannot be made until values for forbidden electron impact cross sections to 3p 5 3d and 3p 5 5s can be obtained. The collisional quenching rates for the cascading levels are measured and found to explain the pressure dependence of the decay of Ar(3p 5 4p) over the full range of pressure except for Ar(3p 5 4p'[1/2] 1 ) which has a unique and interesting behavior at high pressures

Computational methods for constructing protein structure models from 3D electron microscopy maps.

Science.gov (United States)

Esquivel-Rodríguez, Juan; Kihara, Daisuke

2013-10-01

Protein structure determination by cryo-electron microscopy (EM) has made significant progress in the past decades. Resolutions of EM maps have been improving as evidenced by recently reported structures that are solved at high resolutions close to 3Å. Computational methods play a key role in interpreting EM data. Among many computational procedures applied to an EM map to obtain protein structure information, in this article we focus on reviewing computational methods that model protein three-dimensional (3D) structures from a 3D EM density map that is constructed from two-dimensional (2D) maps. The computational methods we discuss range from de novo methods, which identify structural elements in an EM map, to structure fitting methods, where known high resolution structures are fit into a low-resolution EM map. A list of available computational tools is also provided. Copyright © 2013 Elsevier Inc. All rights reserved.

Ligand Electron Density Shape Recognition Using 3D Zernike Descriptors

Science.gov (United States)

Gunasekaran, Prasad; Grandison, Scott; Cowtan, Kevin; Mak, Lora; Lawson, David M.; Morris, Richard J.

We present a novel approach to crystallographic ligand density interpretation based on Zernike shape descriptors. Electron density for a bound ligand is expanded in an orthogonal polynomial series (3D Zernike polynomials) and the coefficients from this expansion are employed to construct rotation-invariant descriptors. These descriptors can be compared highly efficiently against large databases of descriptors computed from other molecules. In this manuscript we describe this process and show initial results from an electron density interpretation study on a dataset containing over a hundred OMIT maps. We could identify the correct ligand as the first hit in about 30 % of the cases, within the top five in a further 30 % of the cases, and giving rise to an 80 % probability of getting the correct ligand within the top ten matches. In all but a few examples, the top hit was highly similar to the correct ligand in both shape and chemistry. Further extensions and intrinsic limitations of the method are discussed.

3D electromagnetic simulation of spatial autoresonance acceleration of electron beams

International Nuclear Information System (INIS)

Dugar-Zhabon, V D; Orozco, E A; González, J D

2016-01-01

The results of full electromagnetic simulations of the electron beam acceleration by a TE 112 linear polarized electromagnetic field through Space Autoresonance Acceleration mechanism are presented. In the simulations, both the self-sustaned electric field and selfsustained magnetic field produced by the beam electrons are included into the elaborated 3D Particle in Cell code. In this system, the space profile of the magnetostatic field maintains the electron beams in the acceleration regime along their trajectories. The beam current density evolution is calculated applying the charge conservation method. The full magnetic field in the superparticle positions is found by employing the trilinear interpolation of the mesh node data. The relativistic Newton-Lorentz equation presented in the centered finite difference form is solved using the Boris algorithm that provides visualization of the beam electrons pathway and energy evolution. A comparison between the data obtained from the full electromagnetic simulations and the results derived from the motion equation depicted in an electrostatic approximation is carried out. It is found that the self-sustained magnetic field is a factor which improves the resonance phase conditions and reduces the beam energy spread. (paper)

Impact of the 3-D model strategy on science learning of the solar system

Science.gov (United States)

Alharbi, Mohammed

The purpose of this mixed method study, quantitative and descriptive, was to determine whether the first-middle grade (seventh grade) students at Saudi schools are able to learn and use the Autodesk Maya software to interact and create their own 3-D models and animations and whether their use of the software influences their study habits and their understanding of the school subject matter. The study revealed that there is value to the science students regarding the use of 3-D software to create 3-D models to complete science assignments. Also, this study aimed to address the middle-school students' ability to learn 3-D software in art class, and then ultimately use it in their science class. The success of this study may open the way to consider the impact of 3-D modeling on other school subjects, such as mathematics, art, and geography. When the students start using graphic design, including 3-D software, at a young age, they tend to develop personal creativity and skills. The success of this study, if applied in schools, will provide the community with skillful young designers and increase awareness of graphic design and the new 3-D technology. Experimental method was used to answer the quantitative research question, are there significant differences applying the learning method using 3-D models (no 3-D, premade 3-D, and create 3-D) in a science class being taught about the solar system and its impact on the students' science achievement scores? Descriptive method was used to answer the qualitative research questions that are about the difficulty of learning and using Autodesk Maya software, time that students take to use the basic levels of Polygon and Animation parts of the Autodesk Maya software, and level of students' work quality.

Case study: Beauty and the Beast 3D: benefits of 3D viewing for 2D to 3D conversion

Science.gov (United States)

Handy Turner, Tara

2010-02-01

From the earliest stages of the Beauty and the Beast 3D conversion project, the advantages of accurate desk-side 3D viewing was evident. While designing and testing the 2D to 3D conversion process, the engineering team at Walt Disney Animation Studios proposed a 3D viewing configuration that not only allowed artists to "compose" stereoscopic 3D but also improved efficiency by allowing artists to instantly detect which image features were essential to the stereoscopic appeal of a shot and which features had minimal or even negative impact. At a time when few commercial 3D monitors were available and few software packages provided 3D desk-side output, the team designed their own prototype devices and collaborated with vendors to create a "3D composing" workstation. This paper outlines the display technologies explored, final choices made for Beauty and the Beast 3D, wish-lists for future development and a few rules of thumb for composing compelling 2D to 3D conversions.

Anisotropy in electron-atom collisions

International Nuclear Information System (INIS)

Linden van den Heuvel, H.B. van.

1982-01-01

Most of the work described in this thesis deals with studies using coincidence experiments, particularly for investigating the electron impact excitation of the 2 1 P and 3 1 D states in helium. A peculiarity is that in the 3 1 D studies the directly emitted 3 1 D → 2 1 P photons are not observed but the 2 1 P → 1 1 S photons resulting from the 3 1 D → 2 1 P → 1 1 S cascade instead. Another interesting point is the choice of the quantisation axis. The author demonstrates that it is of great advantage to take the quantisation axis perpendicular to the scattering plane rather than in the direction of the incident beam, as was done (on historical grounds) in previously reported electron-photon coincidence experiments. Contrary to the incident beam direction the axis perpendicular to the scattering plane really represents an axis of symmetry in the coincidence experiment. In Chapter II the so-called 'parity unfavoured' excitation of the (2p 2 ) 3 P state of helium by electrons is studied. In chapter III the anisotropy parameters for the electron impact excitation of the 2 1 P state of helium in the energy range from 26.6 to 40 eV and in the angular range from 30 0 to 110 0 are determined. Chapter IV contains a description of a scattered electron cascaded-photon coincidence experiment on the electron impact excitation of helium's 3 1 D state. The measurement of complex scattering amplitudes for electron impact excitation of the 3 1 D and 3 1 P states of helium is discussed in Chapter V. (Auth./C.F.)

Electron-impact ionization of Mo+

International Nuclear Information System (INIS)

Ludlow, J.A.; Loch, S.D.; Pindzola, M.S.

2005-01-01

The electron-impact direct ionization cross section for Mo + is calculated using both nonperturbative close-coupling and perturbative distorted-wave methods. When distorted-wave calculations for 4d 5 →4d 4 direct ionization are added to distorted-wave calculations for 4p→nl excitation-autoionization, the experimental measurements are found to be 60% lower than the theoretical predictions. Inclusion of nonperturbative three-body Coulomb effects, present in time-dependent close-coupling calculations, are found to reduce the distorted-wave 4d 5 →4d 4 direct ionization cross section by 25%. This is by far the largest reduction yet seen when comparing the two methods for direct subshell ionization of an atomic positive ion in the ground state. However, when the close-coupling calculations for 4d 5 →4d 4 direct ionization are added to distorted-wave calculations for 4p→nl excitation-autoionization, the experimental measurements are still 45% lower than the theoretical predictions. Although we further investigate correlation effects in the initial target state and term-dependent potential effects in the ejected electron state in an attempt to understand the small magnitude of the experimental measurements, the discrepancy between theory and experiment remains unexplained

3D structure determination from electron-microscope images: Electron crystallography of staurolite. [HFe[sub 2]Al[sub 9]Si[sub 4]O[sub 24

Energy Technology Data Exchange (ETDEWEB)

Wenk, H.R.; Hu Meisheng (California Univ., Berkeley, CA (United States). Dept. of Geology and Geophysics); Downing, K.H. (Lawrence Berkeley Lab., CA (United States). Donner Lab.); O' Keefe, M.A. (Lawrence Berkeley Lab., CA (United States). National Center for Electron Microscopy)

1992-09-01

Resolution of better than 2 A has been obtained in many crystals by high-resolution electron microscopy. Although this resolution is sufficient to resolve interatomic spacings, structures are traditionally interpreted by comparing experimental images with contrast calculations. A drawback of this method is that images are 2D projections in which information is invariably obscured by overlap of atoms. 3D electron crystallography, developed by biophysicists to study proteins, has been used to investigate the crystal structure of staurolite. Amplitudes and phases of structure factors are obtained experimentally from high-resolution images (JEOL ARM 1000 at the National Center for Electron Microscopy at LBL), taken in different directions from thin regions where dynamic scattering is minimal. From images in five orientations (containing 59 independent reflections to a resolution of 1.38 A), a 3D electron potential map is constructed which resolves clearly all cations (Al, Si, Fe, including those with partial occupancy) and all O atoms. This method has great potential in crystal structure determinations of small domains in heterogeneous crystals which are inaccessible to X-ray analysis. It is estimated that 3D structure determinations should be possible on regions only about ten unit cells wide and should resolve not only atom positions but also site occupancies. The method is also applicable to space-group determination. (orig.).

Make or Buy: An Analysis of the Impacts of 3D Printing Operations, 3D Laser Scanning Technology, and Collaborative Product Life-Cycle Management on Ship Maintenance and Modernization Cost Savings

Science.gov (United States)

2015-04-30

ååì~ä=^Åèìáëáíáçå= oÉëÉ~êÅÜ=póãéçëáìã= tÉÇåÉëÇ~ó=pÉëëáçåë= sçäìãÉ=f= = Make or Buy: An Analysis of the Impacts of 3D Printing Operations, 3D Laser...COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Make or Buy: An Analysis of the Impacts of 3D Printing Operations, 3D Laser Scanning...Åèìáëáíáçå=oÉëÉ~êÅÜ=mêçÖê~ãW= `êÉ~íáåÖ=póåÉêÖó=Ñçê=fåÑçêãÉÇ=`Ü~åÖÉ= - 182 - Make or Buy: An Analysis of the Impacts of 3D Printing Operations, 3D Laser

Finite-element 3D simulation tools for high-current relativistic electron beams

Science.gov (United States)

Humphries, Stanley; Ekdahl, Carl

2002-08-01

The DARHT second-axis injector is a challenge for computer simulations. Electrons are subject to strong beam-generated forces. The fields are fully three-dimensional and accurate calculations at surfaces are critical. We describe methods applied in OmniTrak, a 3D finite-element code suite that can address DARHT and the full range of charged-particle devices. The system handles mesh generation, electrostatics, magnetostatics and self-consistent particle orbits. The MetaMesh program generates meshes of conformal hexahedrons to fit any user geometry. The code has the unique ability to create structured conformal meshes with cubic logic. Organized meshes offer advantages in speed and memory utilization in the orbit and field solutions. OmniTrak is a versatile charged-particle code that handles 3D electric and magnetic field solutions on independent meshes. The program can update both 3D field solutions from the calculated beam space-charge and current-density. We shall describe numerical methods for orbit tracking on a hexahedron mesh. Topics include: 1) identification of elements along the particle trajectory, 2) fast searches and adaptive field calculations, 3) interpolation methods to terminate orbits on material surfaces, 4) automatic particle generation on multiple emission surfaces to model space-charge-limited emission and field emission, 5) flexible Child law algorithms, 6) implementation of the dual potential model for 3D magnetostatics, and 7) assignment of charge and current from model particle orbits for self-consistent fields.

Preservation of protein fluorescence in embedded human dendritic cells for targeted 3D light and electron microscopy.

Science.gov (United States)

Höhn, K; Fuchs, J; Fröber, A; Kirmse, R; Glass, B; Anders-Össwein, M; Walther, P; Kräusslich, H-G; Dietrich, C

2015-08-01

In this study, we present a correlative microscopy workflow to combine detailed 3D fluorescence light microscopy data with ultrastructural information gained by 3D focused ion beam assisted scanning electron microscopy. The workflow is based on an optimized high pressure freezing/freeze substitution protocol that preserves good ultrastructural detail along with retaining the fluorescence signal in the resin embedded specimens. Consequently, cellular structures of interest can readily be identified and imaged by state of the art 3D confocal fluorescence microscopy and are precisely referenced with respect to an imprinted coordinate system on the surface of the resin block. This allows precise guidance of the focused ion beam assisted scanning electron microscopy and limits the volume to be imaged to the structure of interest. This, in turn, minimizes the total acquisition time necessary to conduct the time consuming ultrastructural scanning electron microscope imaging while eliminating the risk to miss parts of the target structure. We illustrate the value of this workflow for targeting virus compartments, which are formed in HIV-pulsed mature human dendritic cells. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

Reconstruction of 3D structures of MET antibodies from electron microscopy 2D class averages.

Directory of Open Access Journals (Sweden)

Qi Chen

Full Text Available Dynamics of three MET antibody constructs (IgG1, IgG2, and IgG4 and the IgG4-MET antigen complex was investigated by creating their atomic models with an integrative experimental and computational approach. In particular, we used two-dimensional (2D Electron Microscopy (EM images, image class averaging, homology modeling, Rapidly exploring Random Tree (RRT structure sampling, and fitting of models to images, to find the relative orientations of antibody domains that are consistent with the EM images. We revealed that the conformational preferences of the constructs depend on the extent of the hinge flexibility. We also quantified how the MET antigen impacts on the conformational dynamics of IgG4. These observations allow to create testable hypothesis to investigate MET biology. Our protocol may also help describe structural diversity of other antigen systems at approximately 5 Å precision, as quantified by Root-Mean-Square Deviation (RMSD among good-scoring models.

Electron correlation in CaRuO3 and SrRuO3

International Nuclear Information System (INIS)

Singh, Ravi Shankar; Maiti, Kalobaran

2005-01-01

We investigate the role of electron correlation in the electronic structure of 4d transition-metal oxides CaRuO 3 and SrRuO 3 . The photoemission spectra collected at different surface sensitivities reveal qualitatively different surface and bulk electronic structures in these systems. Extracted bulk spectra could be simulated using first principle approaches consistently with their thermodynamic parameters within the same model. The estimated electron correlation strength (U/W ∼ 0.2) is significantly weak as expected in 4d systems and resolves the long-standing issue that arose due to the prediction of large U/W similar to 3d systems. (author)

Laser characterisation of a 3D single-type column p-type prototype module read out with ATLAS SCT electronics

International Nuclear Information System (INIS)

Ehrich, T.; Kuehn, S.; Boscardin, M.; Dalla Betta, G.-F.; Eckert, S.; Jakobs, K.; Maassen, M.; Parzefall, U.; Piemonte, C.; Pozza, A.; Ronchin, S.; Zorzi, N.

2007-01-01

In this paper measurements of a 3D single-type column (3D-stc) microstrip silicon device are shown. The 3D-stc sensor has n-type columns in p-type substrate. It has been connected to an ATLAS SCT ABCD3T chip and is readout with ATLAS SCT electronics at 40 MHz. Spatial measurements were done with a laser setup to investigate the expected low field region in 3D devices. An influence of the p-stops on the collected charge has been observed

Laser characterisation of a 3D single-type column p-type prototype module read out with ATLAS SCT electronics

Energy Technology Data Exchange (ETDEWEB)

Ehrich, T. [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder Str. 3, 79104 Freiburg (Germany); Kuehn, S. [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder Str. 3, 79104 Freiburg (Germany)], E-mail: susanne.kuehn@physik.uni-freiburg.de; Boscardin, M.; Dalla Betta, G.-F. [ITC-irst Trento, Microsystems Division, via Sommarive, 18 38050 Povo di Trento (Italy); Eckert, S.; Jakobs, K.; Maassen, M.; Parzefall, U. [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder Str. 3, 79104 Freiburg (Germany); Piemonte, C.; Pozza, A.; Ronchin, S.; Zorzi, N. [ITC-irst Trento, Microsystems Division, via Sommarive, 18 38050 Povo di Trento (Italy)

2007-12-11

In this paper measurements of a 3D single-type column (3D-stc) microstrip silicon device are shown. The 3D-stc sensor has n-type columns in p-type substrate. It has been connected to an ATLAS SCT ABCD3T chip and is readout with ATLAS SCT electronics at 40 MHz. Spatial measurements were done with a laser setup to investigate the expected low field region in 3D devices. An influence of the p-stops on the collected charge has been observed.

Role of 3d electrons in formation of ionic-covalent bonds in II-VI based ternary compounds

International Nuclear Information System (INIS)

Lawniczak-Jablonska, K.; Iwanowski, R.J.; Perera, R.C.C.

1997-01-01

In the II-VI compounds doped with transition metals (diluted magnetic semiconductors) a substitution of cation by the introduced magnetic ion leads to hybridization of its 3d states with the sp states of the host semiconductor. The degree of hybridization of the 3d states and its interaction with the host material band states has been a subject of numerous discussions. Inner shell absorption spectroscopy provides very useful means of electronic structure analysis in a wide variety of systems. Due to its selectivity for atomic species and the selection rules for electron transitions, the soft X-ray absorption technique offers quite unique opportunity to measure directly the site-selective local density of the unoccupied d states in the compounds studied. Results are reported for ZnS compounds with Mn, Fe, Co or Ni substitutions for Zn

Photoionization of Co+ and electron-impact excitation of Co2 + using the Dirac R-matrix method

Science.gov (United States)

Tyndall, N. B.; Ramsbottom, C. A.; Ballance, C. P.; Hibbert, A.

2016-11-01

Modelling of massive stars and supernovae (SNe) plays a crucial role in understanding galaxies. From this modelling we can derive fundamental constraints on stellar evolution, mass-loss processes, mixing, and the products of nucleosynthesis. Proper account must be taken of all important processes that populate and depopulate the levels (collisional excitation, de-excitation, ionization, recombination, photoionization, bound-bound processes). For the analysis of Type Ia SNe and core collapse SNe (Types Ib, Ic and II) Fe group elements are particularly important. Unfortunately little data is currently available and most noticeably absent are the photoionization cross-sections for the Fe-peaks which have high abundances in SNe. Important interactions for both photoionization and electron-impact excitation are calculated using the relativistic Dirac atomic R-matrix codes (DARC) for low-ionization stages of Cobalt. All results are calculated up to photon energies of 45 eV and electron energies up to 20 eV. The wavefunction representation of Co III has been generated using GRASP0 by including the dominant 3d7, 3d6[4s, 4p], 3p43d9 and 3p63d9 configurations, resulting in 292 fine structure levels. Electron-impact collision strengths and Maxwellian averaged effective collision strengths across a wide range of astrophysically relevant temperatures are computed for Co III. In addition, statistically weighted level-resolved ground and metastable photoionization cross-sections are presented for Co II and compared directly with existing work.

The Wolff rearrangement of cyclic 2-diazo-1,3-diketones in electron impact - mass spectrometry - controlling the molecular fragmentation by means of low-energy electrons 18 to 70 eV

International Nuclear Information System (INIS)

Kuruc, J.; Kardosova, E.; Nikolaev, V. A.

2016-01-01

The electron-impact-induced fragmentations (the mass spectra, 17 - 70 eV) of cyclic 2-diazo-1,3-diketones were studied. As the suitable compounds were selected the following cyclic 2-diazo-1,3-diketones: 2-diazo-1,3-cyclohexanedione, Ia; 2-diazo-4,4-dimethyl-1,3-cyclohexanedione, Ib; 2-diazo-5,5-dimethyl-1,3-cyclohexanedione, Ic; 2-diazo-4,6-dioxa-5,5-dimethyl-1,3-cyclohexanedione, Id; and 2-diazo-5-phenyl-1,3-cyclohexanedione, Ie). The mass spectra were measured with Varian MAT 111 instrument with direct introduction of samples, with a source temperature of 120 grad C, energy of ionising electrons was in the range (17 - 70) eV. The elimination of the diazo group is the typical reaction of the fragmentation of the cyclic diazo-1,3-diketones after ionization of molecules by electron impact. All our studied cyclic diazo-1,3-diketones have a molecular ion with a relative intensity from 0.7 to 86.4%. Typical ions are [M]"+·, [M-N"_2]"+"·, [M-N_2-CO]"+"·, [M-N_2-CO-CH_2]"+"·, [M-N_2-CO-CH_3]"+"·. For all treatment cyclic diazo-1,3-diketones have been registered 3D mass spectra, for each cyclic diazo-1,3-diketone was proposed fragmentation scheme, including the general fragmentation scheme. The Wolff rearrangement is observed in all studied cyclic diazo-1,3-diketones after cleavage of nitrogen molecules. The energy of ionizing electrons ∼20 eV in the case of compounds Ib, Id - Ie dominating ions are fragments of the [M-N_2]"+"·, in the compound Ia at 18 and 20 eV is dominant fragment [M-N_2-CO-C_2H_2-H]"+"· and for the Ic at 30 eV becomes a dominant fragment [M-N_2-CH_3]"+"· (m/z = 123) but at (25 - 18) eV the most intensive ion is [M-N_2]"+"· (m/z = 138). (authors)

3D analysis of semiconductor devices: A combination of 3D imaging and 3D elemental analysis

Science.gov (United States)

Fu, Bianzhu; Gribelyuk, Michael A.

2018-04-01

3D analysis of semiconductor devices using a combination of scanning transmission electron microscopy (STEM) Z-contrast tomography and energy dispersive spectroscopy (EDS) elemental tomography is presented. 3D STEM Z-contrast tomography is useful in revealing the depth information of the sample. However, it suffers from contrast problems between materials with similar atomic numbers. Examples of EDS elemental tomography are presented using an automated EDS tomography system with batch data processing, which greatly reduces the data collection and processing time. 3D EDS elemental tomography reveals more in-depth information about the defect origin in semiconductor failure analysis. The influence of detector shadowing and X-rays absorption on the EDS tomography's result is also discussed.

Electron correlation effects on the d-d excitations in NiO

NARCIS (Netherlands)

de Graaf, C; Broer, R.; Nieuwpoort, WC

1996-01-01

The partly filled 3d shell in solid transition metal compounds is quite localized on the transition metal ion and gives rise to large electron correlation effects. With the recently developed CASSCF/CASPT2 approach electron correlation effects can be accounted for efficiently. The CASSCF step

Electron-impact ionization cross section of rubidium

International Nuclear Information System (INIS)

Kim, Y.; Migdalek, J.; Siegel, W.; Bieron, J.

1998-01-01

A theoretical model for electron-impact ionization cross section has been applied to Rb and the theoretical cross section (from the threshold to 1 keV in incident energy) is in good agreement with the recent experimental data obtained using Rb atoms trapped in a magneto-optical trap. The theoretical model, called the binary-encounter endash dipole (BED) model, combines a modified Mott cross section with the high-energy behavior of Born cross sections. To obtain the continuum dipole oscillator strength df/dE of the 5s electron required in the BED model, we used Dirac-Fock continuum wave functions with a core polarization potential that reproduced the known position of the Cooper minimum in the photoionization cross section. For inner-shell ionization, we used a simpler version of df/dE, which retained the hydrogenic shape. The contributions of the 4p→4d, 5s, and 5p autoionizing excitations were estimated using the plane-wave Born approximation. As a by-product, we also present the dipole oscillator strengths for the 5s→np 1/2 and 5s→np 3/2 transitions for high principal quantum numbers n near the ionization threshold obtained from the Dirac-Fock wave functions with the same core polarization potential as that used for the continuum wave functions. copyright 1998 The American Physical Society

3D Printed Bionic Nanodevices

Science.gov (United States)

Kong, Yong Lin; Gupta, Maneesh K.; Johnson, Blake N.; McAlpine, Michael C.

2016-01-01

Summary The ability to three-dimensionally interweave biological and functional materials could enable the creation of bionic devices possessing unique and compelling geometries, properties, and functionalities. Indeed, interfacing high performance active devices with biology could impact a variety of fields, including regenerative bioelectronic medicines, smart prosthetics, medical robotics, and human-machine interfaces. Biology, from the molecular scale of DNA and proteins, to the macroscopic scale of tissues and organs, is three-dimensional, often soft and stretchable, and temperature sensitive. This renders most biological platforms incompatible with the fabrication and materials processing methods that have been developed and optimized for functional electronics, which are typically planar, rigid and brittle. A number of strategies have been developed to overcome these dichotomies. One particularly novel approach is the use of extrusion-based multi-material 3D printing, which is an additive manufacturing technology that offers a freeform fabrication strategy. This approach addresses the dichotomies presented above by (1) using 3D printing and imaging for customized, hierarchical, and interwoven device architectures; (2) employing nanotechnology as an enabling route for introducing high performance materials, with the potential for exhibiting properties not found in the bulk; and (3) 3D printing a range of soft and nanoscale materials to enable the integration of a diverse palette of high quality functional nanomaterials with biology. Further, 3D printing is a multi-scale platform, allowing for the incorporation of functional nanoscale inks, the printing of microscale features, and ultimately the creation of macroscale devices. This blending of 3D printing, novel nanomaterial properties, and ‘living’ platforms may enable next-generation bionic systems. In this review, we highlight this synergistic integration of the unique properties of nanomaterials with

3D Printed Bionic Nanodevices.

Science.gov (United States)

Kong, Yong Lin; Gupta, Maneesh K; Johnson, Blake N; McAlpine, Michael C

2016-06-01

The ability to three-dimensionally interweave biological and functional materials could enable the creation of bionic devices possessing unique and compelling geometries, properties, and functionalities. Indeed, interfacing high performance active devices with biology could impact a variety of fields, including regenerative bioelectronic medicines, smart prosthetics, medical robotics, and human-machine interfaces. Biology, from the molecular scale of DNA and proteins, to the macroscopic scale of tissues and organs, is three-dimensional, often soft and stretchable, and temperature sensitive. This renders most biological platforms incompatible with the fabrication and materials processing methods that have been developed and optimized for functional electronics, which are typically planar, rigid and brittle. A number of strategies have been developed to overcome these dichotomies. One particularly novel approach is the use of extrusion-based multi-material 3D printing, which is an additive manufacturing technology that offers a freeform fabrication strategy. This approach addresses the dichotomies presented above by (1) using 3D printing and imaging for customized, hierarchical, and interwoven device architectures; (2) employing nanotechnology as an enabling route for introducing high performance materials, with the potential for exhibiting properties not found in the bulk; and (3) 3D printing a range of soft and nanoscale materials to enable the integration of a diverse palette of high quality functional nanomaterials with biology. Further, 3D printing is a multi-scale platform, allowing for the incorporation of functional nanoscale inks, the printing of microscale features, and ultimately the creation of macroscale devices. This blending of 3D printing, novel nanomaterial properties, and 'living' platforms may enable next-generation bionic systems. In this review, we highlight this synergistic integration of the unique properties of nanomaterials with the

D-, O- and OD- desorption induced by low-energy (0-20 eV) electron impact on amorphous D2O films

International Nuclear Information System (INIS)

Pan Xiaoning; Abdoul-Carime, Hassan; Cloutier, Pierre; Bass, Andrew D.; Sanche, Leon

2005-01-01

We report measurements of low-energy electron stimulated desorption of D - , O - and OD - anions from multilayer amorphous D 2 O films physisorbed on a Pt substrate. The 0-20 eV incident energy dependence (i.e., the yield function) of the desorbed D - yield reveals the presence of a strong peak located at 7.2 eV with a shoulder near 9 eV, which are due to dissociation of the transient states 2 B 1 and 2 A 1 of D 2 O, respectively. The O - and OD - yield functions each exhibit a single broad structure between 5 and 12 eV which also result from dissociative electron attachment (DEA). Due to the weakness of the O - and OD - signals, three possible processes involving DEA must be considered to explain their yield functions, i.e., direct DEA, reactive scattering and DEA to a new product in the film synthesized by the electron beam. It is concluded that at large electron doses (>7.5x10 14 electrons/cm 2 ), these broad peaks arise from DEA to a new product, whereas at lower dose the possibility of direct DEA (i.e., e - +D 2 O→D 2 O - →O - +D 2 and OD - +D) cannot be entirely discounted. Above 15 eV, all anion yield functions exhibit a monotonic rise due to direct dipolar dissociation

DKE: a fast numerical solver for the 3-D relativistic bounce-averaged electron drift kinetic equation

Energy Technology Data Exchange (ETDEWEB)

Decker, J.; Peysson, Y

2004-12-01

A new original code for solving the 3-D relativistic and bounce-averaged electron drift kinetic equation is presented. It designed for the current drive problem in tokamak with an arbitrary magnetic equilibrium. This tool allows self-consistent calculations of the bootstrap current in presence of other external current sources. RF current drive for arbitrary type of waves may be used. Several moments of the electron distribution function are determined, like the exact and effective fractions of trapped electrons, the plasma current, absorbed RF power, runaway and magnetic ripple loss rates and non-thermal Bremsstrahlung. Advanced numerical techniques have been used to make it the first fully implicit (reverse time) 3-D solver, particularly well designed for implementation in a chain of code for realistic current drive calculations in high {beta}{sub p} plasmas. All the details of the physics background and the numerical scheme are presented, as well a some examples to illustrate main code capabilities. Several important numerical points are addressed concerning code stability and potential numerical and physical limitations. (authors)

DKE: a fast numerical solver for the 3-D relativistic bounce-averaged electron drift kinetic equation

International Nuclear Information System (INIS)

Decker, J.; Peysson, Y.

2004-12-01

A new original code for solving the 3-D relativistic and bounce-averaged electron drift kinetic equation is presented. It designed for the current drive problem in tokamak with an arbitrary magnetic equilibrium. This tool allows self-consistent calculations of the bootstrap current in presence of other external current sources. RF current drive for arbitrary type of waves may be used. Several moments of the electron distribution function are determined, like the exact and effective fractions of trapped electrons, the plasma current, absorbed RF power, runaway and magnetic ripple loss rates and non-thermal Bremsstrahlung. Advanced numerical techniques have been used to make it the first fully implicit (reverse time) 3-D solver, particularly well designed for implementation in a chain of code for realistic current drive calculations in high β p plasmas. All the details of the physics background and the numerical scheme are presented, as well a some examples to illustrate main code capabilities. Several important numerical points are addressed concerning code stability and potential numerical and physical limitations. (authors)

Pulse-electron paramagnetic resonance of Cr.sup.3+./sup. centers in SrTiO.sub.3./sub..

Czech Academy of Sciences Publication Activity Database

Azamat, Dmitry; Dejneka, Alexandr; Lančok, Ján; Trepakov, Vladimír; Jastrabík, Lubomír; Badalyan, A. G.

2013-01-01

Roč. 113, č. 17 (2013), "174106-1"-"174106-6" ISSN 0021-8979 R&D Projects: GA MŠk(CZ) LM2011029; GA TA ČR TA01010517; GA ČR GAP108/12/1941 Grant - others:SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 Keywords : pulse-electron paramagnetic resonance * Cr3+ centers in SrTiO 3 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.185, year: 2013

Kinetic electron emission from metal surfaces induced by impact of slow ions

Czech Academy of Sciences Publication Activity Database

Šroubek, Zdeněk; Lorinčík, Jan

-, č. 625 (2014), s. 7-9 ISSN 0039-6028 R&D Projects: GA MŠk(CZ) ME10086 Institutional support: RVO:67985882 Keywords : Ion induced kinetic electron emission * Electronic excitation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.925, year: 2014

YieldStar based reticle 3D measurements and its application

Science.gov (United States)

Vaenkatesan, Vidya; Finders, Jo; ten Berge, Peter; Plug, Reinder; Sijben, Anko; Schellekens, Twan; Dillen, Harm; Pocobiej, Wojciech; Jorge, Vasco G.; van Dijck, Jurgen

2016-09-01

YieldStar (YS) is an established ASML-built scatterometer that is capable of measuring wafer Critical Dimension (CD), Overlay and Focus. In a recent work, the application range of YS was extended to measure 3D CD patterns on a reticle (pattern CD, height, Side Wall Angle-SWA). The primary motivation for this study came from imaging studies that indicated a need for measuring and controlling reticle 3D topography. CD scanning electron microscope (CD-SEM), Atomic force microscope (AFM), 3D multiple detector SEM (3D-SEM) are the preferred tools for reticle metrology. While these tools serve the industry well, the current research to the impact of reticle 3D involves extensive costs, logistic challenges and increased reticle lead time. YS provides an attractive alternative as it can measure pattern CD, SWA and height in a single measurement and at high throughput. This work demonstrates the capability of YS as a reticle metrology tool.

Nonlinear 3D calculations of turbine blade impact on turbine cover

International Nuclear Information System (INIS)

Hatala, B.; Adamik, V.; Buchar, J.

2000-01-01

This paper present the approach used at the VUJE institute for the evaluation of a ruptured blade impact on the current protection cover of a SKODA 220 MW turbine. Firstly, it briefly describes experiments (Hopkinson-Davies split bar facility, Taylor tests) and numerical simulations used to obtain realistic material parameters needed for the Cowper- Symonds material model that is implemented in the code LS-DYNA3D. Then, numerical simulations, by using the code, of the ruptured blade impact on various protection barriers are presented. These simulations make it possible to find an optimal solution for a new turbine protection cover. (author)

ZnO Nanorods on a LaAlO 3 -SrTiO 3 Interface: Hybrid 1D-2D Diodes with Engineered Electronic Properties

KAUST Repository

Bera, Ashok

2015-12-28

Integrating nanomaterials with different dimensionalities and properties is a versatile approach toward realizing new functionalities in advanced devices. Here, a novel diode-type heterostructure is reported consisting of 1D semiconducting ZnO nanorods and 2D metallic LaAlO3-SrTiO3 interface. Tunable insulator-to-metal transitions, absent in the individual components, are observed as a result of the competing temperature-dependent conduction mechanisms. Detailed transport analysis reveals direct tunneling at low bias, Fowler-Nordheim tunneling at high forward bias, and Zener breakdown at high reverse bias. Our results highlight the rich electronic properties of such artificial diodes with hybrid dimensionalities, and the design principle may be generalized to other nanomaterials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ZnO Nanorods on a LaAlO 3 -SrTiO 3 Interface: Hybrid 1D-2D Diodes with Engineered Electronic Properties

KAUST Repository

Bera, Ashok; Lin, Weinan; Yao, Yingbang; Ding, Junfeng; Lourembam, James; Wu, Tao

2015-01-01

Integrating nanomaterials with different dimensionalities and properties is a versatile approach toward realizing new functionalities in advanced devices. Here, a novel diode-type heterostructure is reported consisting of 1D semiconducting ZnO nanorods and 2D metallic LaAlO3-SrTiO3 interface. Tunable insulator-to-metal transitions, absent in the individual components, are observed as a result of the competing temperature-dependent conduction mechanisms. Detailed transport analysis reveals direct tunneling at low bias, Fowler-Nordheim tunneling at high forward bias, and Zener breakdown at high reverse bias. Our results highlight the rich electronic properties of such artificial diodes with hybrid dimensionalities, and the design principle may be generalized to other nanomaterials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of Single-Electron Interface Trapping in Decanano MOSFETs: A 3D Atomistic Simulation Study

Science.gov (United States)

Asenov, Asen; Balasubramaniam, R.; Brown, A. R.; Davies, J. H.

2000-01-01

We study the effect of trapping/detrapping of a single-electron in interface states in the channel of n-type MOSFETs with decanano dimensions using 3D atomistic simulation techniques. In order to highlight the basic dependencies, the simulations are carried out initially assuming continuous doping charge, and discrete localized charge only for the trapped electron. The dependence of the random telegraph signal (RTS) amplitudes on the device dimensions and on the position of the trapped charge in the channel are studied in detail. Later, in full-scale, atomistic simulations assuming discrete charge for both randomly placed dopants and the trapped electron, we highlight the importance of current percolation and of traps with strategic position where the trapped electron blocks a dominant current path.

A 3D Image Filter for Parameter-Free Segmentation of Macromolecular Structures from Electron Tomograms

Science.gov (United States)

Ali, Rubbiya A.; Landsberg, Michael J.; Knauth, Emily; Morgan, Garry P.; Marsh, Brad J.; Hankamer, Ben

2012-01-01

3D image reconstruction of large cellular volumes by electron tomography (ET) at high (≤5 nm) resolution can now routinely resolve organellar and compartmental membrane structures, protein coats, cytoskeletal filaments, and macromolecules. However, current image analysis methods for identifying in situ macromolecular structures within the crowded 3D ultrastructural landscape of a cell remain labor-intensive, time-consuming, and prone to user-bias and/or error. This paper demonstrates the development and application of a parameter-free, 3D implementation of the bilateral edge-detection (BLE) algorithm for the rapid and accurate segmentation of cellular tomograms. The performance of the 3D BLE filter has been tested on a range of synthetic and real biological data sets and validated against current leading filters—the pseudo 3D recursive and Canny filters. The performance of the 3D BLE filter was found to be comparable to or better than that of both the 3D recursive and Canny filters while offering the significant advantage that it requires no parameter input or optimisation. Edge widths as little as 2 pixels are reproducibly detected with signal intensity and grey scale values as low as 0.72% above the mean of the background noise. The 3D BLE thus provides an efficient method for the automated segmentation of complex cellular structures across multiple scales for further downstream processing, such as cellular annotation and sub-tomogram averaging, and provides a valuable tool for the accurate and high-throughput identification and annotation of 3D structural complexity at the subcellular level, as well as for mapping the spatial and temporal rearrangement of macromolecular assemblies in situ within cellular tomograms. PMID:22479430

3D Microstructural Architectures for Metal and Alloy Components Fabricated by 3D Printing/Additive Manufacturing Technologies

Science.gov (United States)

Martinez, E.; Murr, L. E.; Amato, K. N.; Hernandez, J.; Shindo, P. W.; Gaytan, S. M.; Ramirez, D. A.; Medina, F.; Wicker, R. B.

The layer-by-layer building of monolithic, 3D metal components from selectively melted powder layers using laser or electron beams is a novel form of 3D printing or additive manufacturing. Microstructures created in these 3D products can involve novel, directional solidification structures which can include crystallographically oriented grains containing columnar arrays of precipitates characteristic of a microstructural architecture. These microstructural architectures are advantageously rendered in 3D image constructions involving light optical microscopy and scanning and transmission electron microscopy observations. Microstructural evolution can also be effectively examined through 3D image sequences which, along with x-ray diffraction (XRD) analysis in the x-y and x-z planes, can effectively characterize related crystallographic/texture variances. This paper compares 3D microstructural architectures in Co-base and Ni-base superalloys, columnar martensitic grain structures in 17-4 PH alloy, and columnar copper oxides and dislocation arrays in copper.

A method for 3D-reconstruction of a muscle thick filament using the tilt series images of a single filament electron tomogram.

Science.gov (United States)

Márquez, G; Pinto, A; Alamo, L; Baumann, B; Ye, F; Winkler, H; Taylor, K; Padrón, R

2014-05-01

Myosin interacting-heads (MIH) motifs are visualized in 3D-reconstructions of thick filaments from striated muscle. These reconstructions are calculated by averaging methods using images from electron micrographs of grids prepared using numerous filament preparations. Here we propose an alternative method to calculate the 3D-reconstruction of a single thick filament using only a tilt series images recorded by electron tomography. Relaxed thick filaments, prepared from tarantula leg muscle homogenates, were negatively stained. Single-axis tilt series of single isolated thick filaments were obtained with the electron microscope at a low electron dose, and recorded on a CCD camera by electron tomography. An IHRSR 3D-recontruction was calculated from the tilt series images of a single thick filament. The reconstruction was enhanced by including in the search stage dual tilt image segments while only single tilt along the filament axis is usually used, as well as applying a band pass filter just before the back projection. The reconstruction from a single filament has a 40 Å resolution and clearly shows the presence of MIH motifs. In contrast, the electron tomogram 3D-reconstruction of the same thick filament - calculated without any image averaging and/or imposition of helical symmetry - only reveals MIH motifs infrequently. This is - to our knowledge - the first application of the IHRSR method to calculate a 3D reconstruction from tilt series images. This single filament IHRSR reconstruction method (SF-IHRSR) should provide a new tool to assess structural differences between well-ordered thick (or thin) filaments in a grid by recording separately their electron tomograms. Copyright © 2014 Elsevier Inc. All rights reserved.

Intelligent Adjustment of Printhead Driving Waveform Parameters for 3D Electronic Printing

Directory of Open Access Journals (Sweden)

Lin Na

2017-01-01

Full Text Available In practical applications of 3D electronic printing, a major challenge is to adjust the printhead for a high print resolution and accuracy. However, an exhausting manual selective process inevitably wastes a lot of time. Therefore, in this paper, we proposed a new intelligent adjustment method, which adopts artificial bee colony algorithm to optimize the printhead driving waveform parameters for getting the desired printhead state. Experimental results show that this method can quickly and accuracy find out the suitable combination of driving waveform parameters to meet the needs of applications.

Non-equilibrium Modeling of the Fe XVII 3C/3D Line Ratio in an Intense X-Ray Free-Electron Laser Excited Plasma

Science.gov (United States)

Loch, S. D.; Ballance, C. P.; Li, Y.; Fogle, M.; Fontes, C. J.

2015-03-01

Recent measurements using an X-ray Free Electron Laser (XFEL) and an Electron Beam Ion Trap at the Linac Coherent Light Source facility highlighted large discrepancies between the observed and theoretical values for the Fe xvii 3C/3D line intensity ratio. This result raised the question of whether the theoretical oscillator strengths may be significantly in error, due to insufficiencies in the atomic structure calculations. We present time-dependent spectral modeling of this experiment and show that non-equilibrium effects can dramatically reduce the predicted 3C/3D line intensity ratio, compared with that obtained by simply taking the ratio of oscillator strengths. Once these non-equilibrium effects are accounted for, the measured line intensity ratio can be used to determine a revised value for the 3C/3D oscillator strength ratio, giving a range from 3.0 to 3.5. We also provide a framework to narrow this range further, if more precise information about the pulse parameters can be determined. We discuss the implications of the new results for the use of Fe xvii spectral features as astrophysical diagnostics and investigate the importance of time-dependent effects in interpreting XFEL-excited plasmas.

Electron-impact dissociation of molecular hydrogen into neutral fragments

Science.gov (United States)

Scarlett, Liam H.; Tapley, Jonathan K.; Fursa, Dmitry V.; Zammit, Mark C.; Savage, Jeremy S.; Bray, Igor

2018-02-01

We present convergent close-coupling calculations of electron-impact dissociation of the ground state of molecular hydrogen into neutral fragments over the range of impact energies from 6 to 300 eV. The calculations account for dissociative excitation, excitation radiative decay dissociation, and predissociation through all bound electronic triplet states, and singlet states up to the D' 1 Π u state. An estimate is given for the contribution from the remaining bound electronic singlet states. Our results are in agreement with the recommended data of Yoon et al. [J. Phys. Chem. Ref. Data 37, 913 (2008)] in the low (6-12 eV) and high (60-70 eV) energy regions, but somewhat lower at the intermediate energies.

Fitting multimeric protein complexes into electron microscopy maps using 3D Zernike descriptors.

Science.gov (United States)

Esquivel-Rodríguez, Juan; Kihara, Daisuke

2012-06-14

A novel computational method for fitting high-resolution structures of multiple proteins into a cryoelectron microscopy map is presented. The method named EMLZerD generates a pool of candidate multiple protein docking conformations of component proteins, which are later compared with a provided electron microscopy (EM) density map to select the ones that fit well into the EM map. The comparison of docking conformations and the EM map is performed using the 3D Zernike descriptor (3DZD), a mathematical series expansion of three-dimensional functions. The 3DZD provides a unified representation of the surface shape of multimeric protein complex models and EM maps, which allows a convenient, fast quantitative comparison of the three-dimensional structural data. Out of 19 multimeric complexes tested, near native complex structures with a root-mean-square deviation of less than 2.5 Å were obtained for 14 cases while medium range resolution structures with correct topology were computed for the additional 5 cases.

Electronic and optical properties of 2D graphene-like ZnS: DFT calculations

International Nuclear Information System (INIS)

Lashgari, Hamed; Boochani, Arash; Shekaari, Ashkan; Solaymani, Shahram; Sartipi, Elmira; Mendi, Rohollah Taghavi

2016-01-01

Graphical abstract: - Highlights: • DFT has been applied to investigate the optical properties of 2D-ZnS and 3D-ZnS. • The electronic and the optical properties of 3D-ZnS and 2D-ZnS are compared. • At visible range of energies the transparency of 2D-ZnS is more than the 3D. - Abstract: Density-functional theory has been applied to investigate the electronic and optical properties of graphene-like two-dimensional ZnS in the (0001) direction of its Wurtzite phase. A comparison with 3D-ZnS has been carried out within the PBE- and EV-GGA. The electronic properties of 2D- and 3D-ZnS have been derived by the examination of the electronic band structures and density of states. The optical properties have been determined through the study of the dielectric function, reflectivity, electron loss function, refractive and extinction indices, the absorption index and optical conductivity. It is found that the transparency of 2D-ZnS is greater than the 3D over the visible range. A thorough study of the dielectric function has been performed so that the peaks and the transition bands have been specified. The electron loss function demonstrates that the plasmonic frequency for 2D- and 3D-ZnS is accrued at 11.22 and 19.93 eV within the PBE-GGA, respectively.

3D Silicon Coincidence Avalanche Detector (3D-SiCAD) for charged particle detection

Science.gov (United States)

Vignetti, M. M.; Calmon, F.; Pittet, P.; Pares, G.; Cellier, R.; Quiquerez, L.; Chaves de Albuquerque, T.; Bechetoille, E.; Testa, E.; Lopez, J.-P.; Dauvergne, D.; Savoy-Navarro, A.

2018-02-01

Single-Photon Avalanche Diodes (SPADs) are p-n junctions operated in Geiger Mode by applying a reverse bias above the breakdown voltage. SPADs have the advantage of featuring single photon sensitivity with timing resolution in the picoseconds range. Nevertheless, their relatively high Dark Count Rate (DCR) is a major issue for charged particle detection, especially when it is much higher than the incoming particle rate. To tackle this issue, we have developed a 3D Silicon Coincidence Avalanche Detector (3D-SiCAD). This novel device implements two vertically aligned SPADs featuring on-chip electronics for the detection of coincident avalanche events occurring on both SPADs. Such a coincidence detection mode allows an efficient discrimination of events related to an incoming charged particle (producing a quasi-simultaneous activation of both SPADs) from dark counts occurring independently on each SPAD. A 3D-SiCAD detector prototype has been fabricated in CMOS technology adopting a 3D flip-chip integration technique, and the main results of its characterization are reported in this work. The particle detection efficiency and noise rejection capability for this novel device have been evaluated by means of a β- strontium-90 radioactive source. Moreover the impact of the main operating parameters (i.e. the hold-off time, the coincidence window duration, the SPAD excess bias voltage) over the particle detection efficiency has been studied. Measurements have been performed with different β- particles rates and show that a 3D-SiCAD device outperforms single SPAD detectors: the former is indeed capable to detect particle rates much lower than the individual DCR observed in a single SPAD-based detectors (i.e. 2 to 3 orders of magnitudes lower).

Mechanical properties and electronic structure of anti-ReO3 structured cubic nitrides, M3N, of d block transition metals M: An ab initio study

International Nuclear Information System (INIS)

Zhou, Xiuquan; Gall, Daniel; Khare, Sanjay V.

2014-01-01

Highlights: • We use DFT to model the anti-ReO 3 structured transition metal nitrides M 3 N. • We predict their lattice constants, electronic structures and mechanical properties. • We correlate the metal d and nitrogen 2p orbitals with stability and hardness. • We established a high-throughput database for materials design. - Abstract: We report a systematic study of the anti-ReO 3 structured transition metal nitrides, M 3 N, using ab initio density functional theory computations in the local density approximation. Here M denotes all the 3d, 4d and 5d transition metals. Our calculations indicate that all M 3 N compounds except V 3 N of group 5 and Zn 3 N and Hg 3 N of group 12 are mechanically stable. For the stable M 3 N compounds, we report a database of predictions for their lattice constants, electronic properties and mechanical properties including bulk modulus, Young’s modulus, shear modulus, ductility, hardness and Debye temperature. It is found that most M 3 N compounds exhibit ductility with Vickers hardness between 0.4 GPa and 11.2 GPa. Our computed lattice constant for Cu 3 N, the only M 3 N compound where experiments exist, agrees well with the experimentally reported values. We report ratios of the melting points of all M 3 N compounds to that of Cu 3 N. The local density of states for all M 3 N compounds are obtained, and electronic band gaps are observed only for M of group 11 (Cu, Ag and Au) while the remaining M 3 N compounds are metallic without band gaps. Valence electron density along with the hybridization of the metal d and nitrogen 2p orbitals play an important role in determining the stability and hardness of different compounds. Our high-throughput databases for the cubic anti-ReO 3 structured transition metal nitrides should motivate future experimental work and shorten the time to their discovery

Dynamic pulse buckling of cylindrical shells under axial impact: A comparison of 2D and 3D finite element calculations with experimental data

International Nuclear Information System (INIS)

Hoffman, E.L.; Ammerman, D.J.

1995-04-01

A series of tests investigating dynamic pulse buckling of a cylindrical shell under axial impact is compared to several 2D and 3D finite element simulations of the event. The purpose of the work is to investigate the performance of various analysis codes and element types on a problem which is applicable to radioactive material transport packages, and ultimately to develop a benchmark problem to qualify finite element analysis codes for the transport package design industry. Four axial impact tests were performed on 4 in-diameter, 8 in-long, 304 L stainless steel cylinders with a 3/16 in wall thickness. The cylinders were struck by a 597 lb mass with an impact velocity ranging from 42.2 to 45.1 ft/sec. During the impact event, a buckle formed at each end of the cylinder, and one of the two buckles became unstable and collapsed. The instability occurred at the top of the cylinder in three tests and at the bottom in one test. Numerical simulations of the test were performed using the following codes and element types: PRONTO2D with axisymmetric four-node quadrilaterals; PRONTO3D with both four-node shells and eight-node hexahedrons; and ABAQUS/Explicit with axisymmetric two-node shells and four-node quadrilaterals, and 3D four-node shells and eight-node hexahedrons. All of the calculations are compared to the tests with respect to deformed shape and impact load history. As in the tests, the location of the instability is not consistent in all of the calculations. However, the calculations show good agreement with impact load measurements with the exception of an initial load spike which is proven to be the dynamic response of the load cell to the impact. Finally, the PRONIT02D calculation is compared to the tests with respect to strain and acceleration histories. Accelerometer data exhibited good qualitative agreement with the calculations. The strain comparisons show that measurements are very sensitive to gage placement

The 4p6 autoionization cross section of Rb atoms excited by low-energy electron impact

International Nuclear Information System (INIS)

Borovik, A; Roman, V; Kupliauskienė, A

2012-01-01

The autoionization cross section of rubidium atoms was obtained by measuring the total normalized intensities of ejected-electron spectra arising from the decay of the 4p 5 n 1 l 1 n 2 l 2 autoionizing levels. The electron impact energy range from the 4p 6 excitation threshold at 15.31 up to 50 eV was investigated. The cross section reaches the maximum value of (2.9 ± 0.6) × 10 −16  cm 2 at 21.8 eV impact energy. The general behaviours of the cross section and the role of particular autoionizing configurations in its formation were considered on the basis of large-scale configuration interaction calculations of energies, cross sections, autoionization probabilities in 5snl(n ⩽ 7; l ⩽ 4) and 4d nl(n ⩽ 5; l ⩽ 2) configurations as well as the measured excitation functions for the lowest levels in 5s 2 and 4d5s configurations. The resonance behaviour of the cross section between 15.3 and 18.5 eV impact energy is caused exclusively by the negative-ion resonances present close to the excitation thresholds of the (5s 2 ) 2 P and (4d5s) 4 P autoionizing levels. At higher impact energies, the autoionization cross section is composed of contributions from the high-lying quartet and doublet levels in 4d5s, 5p and 5s5p, 5d, 6s, 6p configurations. From the comparison of the present data with available experimental and calculated ionization cross sections, the 5s + 4p 6 direct ionization cross section of rubidium atoms was determined with the maximum value of (7.2 ± 2.2) × 10 −16  cm 2 at 36 eV. It was also found that the 4p 6 excitation–autoionization is the dominant indirect ionization process contributing over 30% of the total single ionization of rubidium atoms by electron impact in the 15.3–50 eV energy range. (paper)

3D Reconstruction of the Glycocalyx Structure in Mammalian Capillaries using Electron Tomography

DEFF Research Database (Denmark)

Arkill, Kp; Neal, Cr; Mantell, Jm

2012-01-01

of the proteoglycan components of the glycocalyx layer (fundamental spacing about 20 nm), but require a large sample number. Attempts to visualise the glycocalyx face-on (i.e. in a direction perpendicular to the endothelial cell layer in the lumen and directly applicable for permeability modelling) has had limited...... success (e.g. freeze fracture). A new approach is therefore needed. Here we demonstrate the effectiveness of using the relatively novel electron microscopy technique of 3D electron tomography ontwo differently stained preparations to reveal details of the architecture of the glycocalyx just above...... the endothelial cell layer. One preparation uses the novel staining technique using Lanthanum Dysprosium Glycosamino Glycan adhesion (the LaDy GAGa method). © 2012 John Wiley & Sons Ltd....

3D Characterization of Recrystallization Boundaries

DEFF Research Database (Denmark)

Zhang, Yubin; Godfrey, Andrew William; MacDonald, A. Nicole

2016-01-01

A three-dimensional (3D) volume containing a recrystallizing grain and a deformed matrix in a partially recrystallized pure aluminum was characterized using the 3D electron backscattering diffraction technique. The 3D shape of a recrystallizing boundary, separating the recrystallizing grain...... on the formation of protrusions/retrusions....

Electron spectroscopy of He and NO using electron impact and multiphoton ionisation

International Nuclear Information System (INIS)

Kimman, J.T.N.

1984-01-01

This thesis describes two experimental studies which are intended to contribute to our knowledge of the structure of molecules and the decay dynamics of excited molecular states. The two studies have in common that they are both concerned with ionisation processes, in which an accurately known amount of energy is transferred to the target, and energy analysis of the ejected electrons is made. Ionisation is caused either by scattering electrons off the molecules (chapter 2: electron impact ionisation) or by a simultaneous absorption of several photons (chapter 3: multiphoton ionisation). In chapter 2 an electron impact ionisation experiment on Helium is described in which the kinematics of both the scattered and the ejected electrons is fully determined ((e,2e) experiment). (Auth.)

Spin-polarized electron capture for the Na+3He2+ system at a 3He2+ impact energy of 5.33--9.33 keV/amu

International Nuclear Information System (INIS)

Tanaka, M.; Shimakura, N.; Ohshima, T.; Katori, K.; Fujiwara, M.; Ogata, H.; Kondo, M.

1994-01-01

3 He + atomic polarizations following the spin-polarized electron capture process for the N rvec a(3s)+ 3 He 2+ system were measured at 3 He 2+ impact energies from 5.33 to 9.33 keV/amu. The magnitude of the 3 He + atomic polarizations was deduced from the 3 He + nuclear polarization measured by means of beam-foil spectroscopy. The observed polarization transfer coefficient P T defined by the ratio of the 3 He + atomic polarization to the sodium one showed a pronounced reduction from unity, which was qualitatively explained by the prediction of a simple cascade photon decay model. Evidence for a further reduction of P T from the above model and a possible impact energy dependence of P T suggested an excessive depolarization due to the presence of the collision alignment parameter A 0 col of 3 He + formed by the electron capture process. In order to see this more closely, the observed P T 's were examined theoretically using the semiclassical impact parameter method, in which an 18-state molecular expansion was employed, and atomic-type electron translation effects were rigorously taken into account. Ensuring that both the absolute values and the impact energy dependence of the observed capture cross sections were remarkably well reproduced by the calculations in which the states up to 4f in 3 He + were introduced, it was demonstrated that the calculated results for P T qualitatively reproduced not only the absolute values of the observed P T 's but also their gentle decrease with increasing impact energy. Production of nuclear polarizations resulting from the polarized electron capture processes between multicharged heavy ions and alkaline-earth-metal atoms is an example of one use of the future project of universal polarized heavy-ion sources

3D Anatomy Models and Impact on Learning: A Review of the Quality of the Literature

Directory of Open Access Journals (Sweden)

Samy A. Azer

2016-12-01

Conclusions: There was no solid evidence that the use of 3D models is superior to traditional teaching. However, the studies varied in research quality. More studies are needed to examine the short- and long-term impacts of 3D models on learning using valid and appropriate tools.

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.

Pressure effects on the 2D electron system in LaAlO{sub 3}/SrTiO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Borisov, Vladislav; Jeschke, Harald O.; Valenti, Roser [Institute of Theoretical Physics, Goethe University, D-60438 Frankfurt am Main (Germany); Zabaleta, Jone [Max Planck Institute for Solid State Research, D-70569 Stuttgart (Germany); Kopp, Thilo [Center for Electronic Correlations and Magnetism, Experimental Physics VI, Institute of Physics, University of Augsburg, D-86135 Augsburg (Germany)

2016-07-01

We present a theoretical study of pressure effects on the electronic properties of the LaAlO{sub 3}/SrTiO{sub 3} (001) interface. Lattice relaxation plays a crucial role for the formation of the 2D electron system (2DES), in agreement with previous reports. We observe that the carrier density of the 2DES at zero pressure is much lower than the ''polar catastrophe'' estimate of 0.5 e{sup -} per two-dimensional unit cell, which agrees with most experimental works. Under hydrostatic pressure, structural distortions in LaAlO{sub 3} (LAO) are largely suppressed, whereas they increase in SrTiO{sub 3} (STO), and the carrier density of the 2DES is enhanced by almost 45% using a moderate pressure of 4.1 GPa. The origin of this behavior as well as the explanation for the low carrier density at the interface at ambient pressure are discussed in terms of the lattice polarization and electronic Berry phase in the LAO oxide. Reduction of the calculated static dielectric constants of LAO and STO under pressure might account for the recent experimental findings regarding the carrier mobility.

3D Plant Cell Architecture of Arabidopsis thaliana (Brassicaceae Using Focused Ion Beam–Scanning Electron Microscopy

Directory of Open Access Journals (Sweden)

Bhawana

2014-06-01

Full Text Available Premise of the study: Focused ion beam–scanning electron microscopy (FIB-SEM combines the ability to sequentially mill the sample surface and obtain SEM images that can be used to create 3D renderings with micron-level resolution. We have applied FIB-SEM to study Arabidopsis cell architecture. The goal was to determine the efficacy of this technique in plant tissue and cellular studies and to demonstrate its usefulness in studying cell and organelle architecture and distribution. Methods: Seed aleurone, leaf mesophyll, stem cortex, root cortex, and petal lamina from Arabidopsis were fixed and embedded for electron microscopy using protocols developed for animal tissues and modified for use with plant cells. Each sample was sectioned using the FIB and imaged with SEM. These serial images were assembled to produce 3D renderings of each cell type. Results: Organelles such as nuclei and chloroplasts were easily identifiable, and other structures such as endoplasmic reticula, lipid bodies, and starch grains were distinguishable in each tissue. Discussion: The application of FIB-SEM produced 3D renderings of five plant cell types and offered unique views of their shapes and internal content. These results demonstrate the usefulness of FIB-SEM for organelle distribution and cell architecture studies.

GGA+U investigations of impurity d-electrons effects on the electronic and magnetic properties of ZnO

KAUST Repository

Ul Haq, Bakhtiar

2014-08-01

Stimulation of novel features in ZnO by impurity electrons has attracted a remarkable attention of researchers from the past decade. Consequently, ZnO has found several applications in the field of spintronics and optoelectronics. We report, the effect of 3d-(V, Ag) electrons on the properties of ZnO in stable wurtzite (WZ) and metastable zincblende (ZB) phase using the density functional theory. Introduction of V-3d electrons was found to induce a high magnetic moment value of 5.22 in WZ and 3.26 in the ZB phase, and moreover transform the semiconductor character of ZnO into a metallic nature. Ag-d electrons result in the p-type half-metallic nature of ZnO with a weak ferromagnetic background. Our calculations for ground-state magnetic ordering show that ZnO in the presence of impure 3d-(V, Ag) electrons favors ferromagnetic ordering, and obey the double exchange mechanism. However, impurity atoms have very marginal effect on the lattice parameters of ZnO, thereby exposing its potential to absorb the impurity atoms in high concentration. © 2014 Elsevier B.V. All rights reserved.

Electron impact with argon excitation out of the e-Ar(3p54s,J = 2)

International Nuclear Information System (INIS)

Jin Shiqi; Xu Zhizhan

1998-01-01

It is shown that the electron impact with argon excitation out of the metastable to the 3p 5 4p levels is very important for spectrum, laser physics and plasma processing. Analysis of the cross sections of 3p 5 4p, J = 3 level in manifolds of 3p 5 4p is valuable. It also provides the atomic character of emission harmonics in intense laser field

LandSIM3D: modellazione in real time 3D di dati geografici

Directory of Open Access Journals (Sweden)

Lambo Srl Lambo Srl

2009-03-01

Full Text Available LandSIM3D: realtime 3D modelling of geographic data LandSIM3D allows to model in 3D an existing landscape in a few hours only and geo-referenced offering great landscape analysis and understanding tools. 3D projects can then be inserted into the existing landscape with ease and precision. The project alternatives and impact can then be visualized and studied into their immediate environmental. The complex evolution of the landscape in the future can also be simulated and the landscape model can be manipulated interactively and better shared with colleagues. For that reason, LandSIM3D is different from traditional 3D imagery solutions, normally reserved for computer graphics experts. For more information about LandSIM3D, go to www.landsim3d.com.

He I D3 OBSERVATIONS OF THE 1984 MAY 22 M6.3 SOLAR FLARE

Energy Technology Data Exchange (ETDEWEB)

Liu Chang; Xu Yan; Deng Na; Lee, Jeongwoo; Zhang Jifeng; Wang Haimin [Space Weather Research Laboratory, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States); Prasad Choudhary, Debi, E-mail: chang.liu@njit.edu [Physics and Astronomy Department, California State University Northridge, 18111 Nordhoff Street, Northridge, CA 91330-0001 (United States)

2013-09-01

The He I D3 line has a unique response to a flare impact on the low solar atmosphere and can be a powerful diagnostic tool for energy transport processes. Using images obtained from the recently digitized films of the Big Bear Solar Observatory, we report D3 observations of the M6.3 flare on 1984 May 22, which occurred in an active region with a circular magnetic polarity inversion line (PIL). The impulsive phase of the flare starts with a main elongated source that darkens in D3, inside of which bright emission kernels appear at the time of the initial small peak in hard X-rays (HXRs). These flare cores subsequently evolve into a sharp emission strand lying within the dark halo; this evolution occurs at the same time as the main peak in HXRs, reversing the overall source contrast from -5% to 5%. The radiated energy in D3 during the main peak is estimated to be about 10{sup 30} erg, which is comparable to that carried by nonthermal electrons above 20 keV. Afterward, the flare proceeds along the circular PIL in the counterclockwise direction to form a dark circular ribbon in D3, which apparently mirrors the bright ribbons in H{alpha} and He I 10830 A. All of these ribbons last for over one hour in the late gradual phase. We suggest that the present event resembles the so-called black-light flare that was proposed based on continuum images, and that D3 darkening and brightening features herein may be due to thermal conduction heating and the direct precipitation of high-energy electrons, respectively.

Crossover from 2d to 3d in anisotropic Kondo lattices

International Nuclear Information System (INIS)

Reyes, D.; Continentino, M.A.

2008-01-01

We study the crossover from two to three dimensions in Kondo lattices (KLM) using the Kondo necklace model (KNM). In order to diagonalize the KNM, we use a representation for the localized and conduction electron spins in terms of bond operators and a decoupling for the relevant Green's functions. Both models have a quantum critical point at a finite value of the ratio (J/t) between the Kondo coupling (J) and the hopping (t). In 2d there is no line of finite temperature antiferromagnetic (AF) transitions while for d≥3 this line is given by, T N ∝|g| 1/(d-1) [D. Reyes, M.A. Continentino, Phys. Rev. B 76 (2007) 075114]. The crossover from 2d to 3d is investigated by turning on the electronic hopping (t -perpendicular ) of conduction electrons between different planes. The phase diagram as a function of temperature T, J/t -parallel and ξ=t -perpendicular /t -parallel , where t -parallel is the hopping within the planes is calculated

Electron-impact excitation of Fe II: Effective collision strengths for optically allowed fine-structure transitions

International Nuclear Information System (INIS)

Ramsbottom, C.A.

2009-01-01

In this paper, we present collision strengths and Maxwellian averaged effective collision strengths for the electron-impact excitation of Fe II. We consider specifically the optically allowed lines for transitions from the 3d 6 4s and 3d 7 even parity configuration states to the 3d 6 4p odd parity configuration levels. The parallel suite of Breit-Pauli codes are utilized to compute the collision cross-sections where relativistic effects are included explicitly in both the target and the scattering approximation. A total of 100 LS or 262-jj levels formed from the basis configurations 3d 6 4s, 3d 7 and 3d 6 4p were included in the wavefunction representation of the target, including all doublet, quartet and sextet terms. The Maxwellian averaged effective collision strengths are computed across a wide range of electron temperatures from 100 to 100,000 K, temperatures of importance in astrophysical and plasma applications. A detailed comparison is made with previous works and significant differences were found to occur for some of the transitions considered. We conclude that in order to obtain converged collision strengths and effective collision strengths for these allowed transitions it is necessary to include contributions from partial waves up to L = 50 explicitly in the calculation, and in addition, account for contributions from even higher partial waves through a 'top up' procedure.

3-D printers for libraries

CERN Document Server

Griffey, Jason

2014-01-01

As the maker movement continues to grow and 3-D printers become more affordable, an expanding group of hobbyists is keen to explore this new technology. In the time-honored tradition of introducing new technologies, many libraries are considering purchasing a 3-D printer. Jason Griffey, an early enthusiast of 3-D printing, has researched the marketplace and seen several systems first hand at the Consumer Electronics Show. In this report he introduces readers to the 3-D printing marketplace, covering such topics asHow fused deposition modeling (FDM) printing workBasic terminology such as build

Prosthesis-patient mismatch after transcatheter aortic valve implantation: impact of 2D-transthoracic echocardiography versus 3D-transesophageal echocardiography.

Science.gov (United States)

da Silva, Cristina; Sahlen, Anders; Winter, Reidar; Bäck, Magnus; Rück, Andreas; Settergren, Magnus; Manouras, Aristomenis; Shahgaldi, Kambiz

2014-12-01

To investigate the role of 2D-transthoracic echocardiography (2D-TTE) and 3D-transesophageal echocardiography (3D-TEE) in the determination of aortic annulus size prior transcatheter aortic valve implantation (TAVI) and its' impact on the prevalence of patient prosthesis mismatch (PPM). Echocardiography plays an important role in measuring aortic annulus dimension in patients undergoing TAVI. This has great importance since it determines both eligibility for TAVI and selection of prosthesis type and size, and can be potentially important in preventing an inadequate ratio between the prosthetic valvular orifice and the patient's body surface area, concept known as prosthesis-patient mismatch (PPM). A total of 45 patients were studied pre-TAVI: 20 underwent 3D-TEE (men/women 12/8, age 84.8 ± 5.6) and 25 2D-TTE (men/women 9/16, age 84.4 ± 5.4) in order to measure aortic annulus diameter. The presence of PPM was assessed before hospital discharge and after a mean period of 3 months. Moderate PPM was defined as indexed aortic valve area (AVAi) ≤ 0.85 cm(2)/m(2) and severe PPM as AVAi 3D-TEE and 2D-TTE respectively p value = n.s) and severe PPM occurred in 10 % of the patients who underwent 3D-TEE and in 20 % in those with 2D-TTE (p value = n.s). The echocardiographic evaluation 3 months post-TAVI showed 25 % moderate PPM in the 3D-TEE group compared with 24 % in the 2D-TTE group (p value = n.s) and no cases of severe PPM in the 3DTEE group comparing to 20 % in the 2D-TTE group (p = 0.032). Our results indicate a higher incidence of severe PPM in patients who performed 2DTTE compared to those performing 3DTEE prior TAVI. This suggests that the 3D technique should replace the 2DTTE analysis when investigating the aortic annulus diameter in patients undergoing TAVI.

A 3D technique for simulation of irregular electron treatment fields using a digital camera

International Nuclear Information System (INIS)

Bassalow, Roustem; Sidhu, Narinder P.

2003-01-01

Cerrobend inserts, which define electron field apertures, are manufactured at our institution using perspex templates. Contours are reproduced manually on these templates at the simulator from the field outlines drawn on the skin or mask of a patient. A previously reported technique for simulation of electron treatment fields uses a digital camera to eliminate the need for such templates. However, avoidance of the image distortions introduced by non-flat surfaces on which the electron field outlines were drawn could only be achieved by limiting the application of this technique to surfaces which were flat or near flat. We present a technique that employs a digital camera and allows simulation of electron treatment fields contoured on an anatomical surface of an arbitrary three-dimensional (3D) shape, such as that of the neck, extremities, face, or breast. The procedure is fast, accurate, and easy to perform

Comparison between 3D dynamics filter technique, field-in-field, electronic compensator in breast cancer; Comparacao entre tecnica 3D com filtro dinamico, field-in-field e compensacao eletronica para cancer de mama

Energy Technology Data Exchange (ETDEWEB)

Trindade, Cassia; Silva, Leonardo P.; Martins, Lais P.; Garcia, Paulo L.; Santos, Maira R.; Bastista, Delano V.S.; Vieira, Anna Myrian M.T.L.; Rocha, Igor M., E-mail: cassiatr@gmail.com [Instituto Nacional de Cancer (INCA), Rio de Janeiro, RJ (Brazil)

2012-12-15

The radiotherapy has been used in a wild scale in breast cancer treatment. With this high demand, new technologies have been developed to improve the dose distribution in the target while reducing the dose delivered in critical organs. In this study, performed with one clinical case, three planning were done for comparison: 3D technique with dynamic filter, 3D with field-in-field technique (forward-planned IMRT) and 3D technique using electronic compensator (ECOMP). The planning were done with a 6MV photon beam using the Eclipse software, version 8.6 (Varian Medical Systems). The PTV was drawn covering the whole breast and the critical organs were: the lung on the irradiated side, the heart, the contralateral breast and the anterior descending coronary artery (LAD). The planning using the compensator technique permitted more homogeneous dose distribution in the target volume. The V20 value of the lung on the irradiated side was 8,3% for the electronic compensator technique, 8,9% for the field-in-field technique and 8,2% for the dynamic filter technique. For the heart the dose range was 15.7 - 139.9 cGy, 16.3 - 148.4 cGy for the dynamic filter technique and 19.6 - 157.0 cGy for the field-in-field technique. The dose gradient was 11% with compensator electronic, 15% dynamic filter technique and 13% with field-in-field. The application of electronic technique in breast cancer treatment allows better dose distribution while reduces dose in critical organs, but in the same time requires a quality assurance. (author)

3D scanning electron microscopy applied to surface characterization of fluorosed dental enamel.

Science.gov (United States)

Limandri, Silvina; Galván Josa, Víctor; Valentinuzzi, María Cecilia; Chena, María Emilia; Castellano, Gustavo

2016-05-01

The enamel surfaces of fluorotic teeth were studied by scanning electron stereomicroscopy. Different whitening treatments were applied to 25 pieces to remove stains caused by fluorosis and their surfaces were characterized by stereomicroscopy in order to obtain functional and amplitude parameters. The topographic features resulting for each treatment were determined through these parameters. The results obtained show that the 3D reconstruction achieved from the SEM stereo pairs is a valuable potential alternative for the surface characterization of this kind of samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Spectroscopie du Furanne et du Thiophene Par Diffusion Inelastique D'electrons

Science.gov (United States)

Lotfi, Said

Nous avons etudie les molecules de furanne ( rm C_4H_4O) et de thiophene (rm C_4H_4O) au moyen de la spectroscopie de diffusion inelastique d'electrons. Pour (rm C_4H_4O), les spectres realises dans differentes conditions d'energie d'impact et d'angle de diffusion contiennent des singularites ou des families de pics correspondant a: (1) des vibrations de l'etat fondamental dans le domaine 0-0.5 eV, (2) des etats triplets ^3 B_1 et ^3 A_1 qui dominent la region 3-5.5 eV, (3) des etats de valences, entre 5 et 10 eV, dont certains son accompagnes de progressions vibrationnelles, soit ~ A _1B_2, ~ B ^1A_1 et ~ C ^1A_1, (4) toujours entre 5 et 10 eV, deux series de Ryhdberg (rm 1a_2to nda_2 et rm 1a_2to npb_2) qui convergent vers la premiere limite d'ionisation de la molecule, avec une progression vibrationnelle associee au mdoe nu_4 pour la seconde, et une troisieme serie (rm 2b_1to nsa_1 ) convergent vers la seconde limite d'ionisation accompagnee de la progression de mode nu _1. Pour rm C_4H_4S, nos spectres presentent les memes etats de vibration et les memes etats triplets que pour rm C_4H _4O. Nous avons releve egalement, dans la region de 5 a 10 eV, des etats de valence ~ A ^1A_1 (ou ~ A ^1B_2), ~ B ^1A_1 (ou ~ B ^1B _2) et ~ C ^1A_1 (ou ~ C ^1B_2). Pour la premiere fois, par la spectroscopie de diffusion inelastique d'electrons, de nombreux pics ont ete identifies et attribues, dans le cadre de ce travail. Il s'agit, notamment, des etats de vibration de l'etat electronique fondamental de ces molecules et egalement de certains etats de Rydberg dans le cas du furanne.

Advanced prior modeling for 3D bright field electron tomography

Science.gov (United States)

Sreehari, Suhas; Venkatakrishnan, S. V.; Drummy, Lawrence F.; Simmons, Jeffrey P.; Bouman, Charles A.

2015-03-01

Many important imaging problems in material science involve reconstruction of images containing repetitive non-local structures. Model-based iterative reconstruction (MBIR) could in principle exploit such redundancies through the selection of a log prior probability term. However, in practice, determining such a log prior term that accounts for the similarity between distant structures in the image is quite challenging. Much progress has been made in the development of denoising algorithms like non-local means and BM3D, and these are known to successfully capture non-local redundancies in images. But the fact that these denoising operations are not explicitly formulated as cost functions makes it unclear as to how to incorporate them in the MBIR framework. In this paper, we formulate a solution to bright field electron tomography by augmenting the existing bright field MBIR method to incorporate any non-local denoising operator as a prior model. We accomplish this using a framework we call plug-and-play priors that decouples the log likelihood and the log prior probability terms in the MBIR cost function. We specifically use 3D non-local means (NLM) as the prior model in the plug-and-play framework, and showcase high quality tomographic reconstructions of a simulated aluminum spheres dataset, and two real datasets of aluminum spheres and ferritin structures. We observe that streak and smear artifacts are visibly suppressed, and that edges are preserved. Also, we report lower RMSE values compared to the conventional MBIR reconstruction using qGGMRF as the prior model.

Optoelectronic interconnects for 3D wafer stacks

Science.gov (United States)

Ludwig, David; Carson, John C.; Lome, Louis S.

1996-01-01

Wafer and chip stacking are envisioned as means of providing increased processing power within the small confines of a three-dimensional structure. Optoelectronic devices can play an important role in these dense 3-D processing electronic packages in two ways. In pure electronic processing, optoelectronics can provide a method for increasing the number of input/output communication channels within the layers of the 3-D chip stack. Non-free space communication links allow the density of highly parallel input/output ports to increase dramatically over typical edge bus connections. In hybrid processors, where electronics and optics play a role in defining the computational algorithm, free space communication links are typically utilized for, among other reasons, the increased network link complexity which can be achieved. Free space optical interconnections provide bandwidths and interconnection complexity unobtainable in pure electrical interconnections. Stacked 3-D architectures can provide the electronics real estate and structure to deal with the increased bandwidth and global information provided by free space optical communications. This paper will provide definitions and examples of 3-D stacked architectures in optoelectronics processors. The benefits and issues of these technologies will be discussed.

Excitation and ionization of highly charged ions by electron impact

International Nuclear Information System (INIS)

Sampson, D.H.

1989-01-01

Two approaches for very rapid calculation of atomic data for high temperature plasma modeling have been developed. The first uses hydrogenic basis states and has been developed and applied in many papers discussed in previous progress reports. Hence, it is only briefly discussed here. The second is a very rapid, yet accurate, fully relativistic approach that has been developed over the past two or three years. It is described in more detail. Recently it has been applied to large scale production of atomic data. Specifically, it has been used to calculate relativistic distorted wave collision strengths and oscillator strengths for the following: all transitions from the ground level to the n=3 and 4 excited levels in the 71 Neon-like ions with nuclear charge number Z in the range 22 ≤ Z ≤ 92; all transitions among the 2s 1/2 , 2p 1/2 and 2p 3/2 levels and from them to all nlj levels with n=3,4 and 5 in the 85 Li-like ions with 8 ≤ Z ≤ 92; all transitions among the 3s 1/2 , 3p 3/2 , 3d 3/2 and 3d 5/2 levels and from them to all nlj levels with n=4 and 5 in the 71 Na-like ions with 22 ≤ Z ≤ 92; and all transitions among 4s 1/2 , 4p 1/2 , 4p 3/2 , 4d 3/2 , 4d 5/2 , 4f 5/2 and 4f 7/2 levels and from them to all nlj levels with n=5 in the 33 Cu-like ions with 60 ≤ Z ≤ 92. Also the program has been extended to give cross-sections for excitation to specific magnetic sublevels of the target ion by an electron beam and very recently it has been extended to give relativistic distorted wave cross sections for ionization of highly charged ions by electron impact

A DYNA3D calculation for impact on a pipe target

International Nuclear Information System (INIS)

Neilson, A.J.

1983-11-01

This report describes experimental studies to examine the response of pipework, typical of that used in nuclear power plants, to the impact of missiles representing fragments of disintegrating machinery. The finite element code DYNA3D has been used to make a calculation for one experiment in which an instrumented target pipe was impacted by a cylindrical steel billet. Transient displacement of the missile and target as well as permanent deformations of the target pipe were well-predicted by the code. The code reproduced the main features of the experimental transient strain measurements with the timings of the various straining phases being calculated very closely. Detailed quantitative comparisons cannot be made because of the lack of appropriate facilities in the GRAPE post-processing code. (U.K.)

Impacts of Built-Up Area Expansion in 2D and 3D on Regional Surface Temperature

Directory of Open Access Journals (Sweden)

Hongyan Cai

2017-10-01

Full Text Available Many studies have reported the thermal effects of urban expansion from non-built-up land; however, how changes in building height in built-up land influence the regional thermal environment is still uncertain. Thus, taking the transitional region between the Chinese megacities of Beijing and Tianjin as the study area, this study investigated the impacts of built-up land expansion in 2D and 3D on regional land surface temperature (LST. The expansion in 2D refers to the conversion from non-built-up land to built-up land, whereas the expansion in 3D characterized the building height change in the built-up land, referring to the conversion from low- and moderate-rise building (LMRB to high-rise building (HRB lands. The land use change from 2010 to 2015 was manually interpreted from high spatial resolution SPOT5 and Gaofen2 images, and the LST information in the corresponding period was derived from Landsat5/8 thermal images using an image-based method. The results showed that between 2010 and 2015, approximately 87.25 km2 non-built-up land was transformed to built-up land, and 13.21 km2 LMRB land was built into HRB land. These two types of built-up land expansions have induced opposing thermal effects in regard to regional surface temperature. The built-up land expansions from cropland and urban green land have raised the regional LST. However, the built-up land expansion from LMRB to HRB lands has induced a cooling effect. Thus, this study suggested that for the cooling urban design, the building height should also be considered. Furthermore, for future studies on thermal impacts of urbanization, it should be cautioned that, besides the urban area expansion, the building height change should also be emphasized due to its potential cooling effects.

An inkjet printed near isotropic 3-D antenna with embedded electronics for wireless sensor applications

KAUST Repository

Farooqui, Muhammad Fahad

2014-07-01

A 3-D (cube-shaped) antenna, which has been inkjet printed on a paper substrate and integrated with embedded electronics, is presented for the first time. A 1.5λ0 dipole is uniquely implemented on all the faces of the cube to achieve near isotropic radiation pattern. The antenna measures 13mm × 13mm × 13mm, where each side of the cube corresponds to only 0.1λ0 (at 2.4 GHz). Measurements with driving electronics placed inside the cube have shown that the antenna performance is not affected by the presence of embedded circuits. The cube antenna design is highly suitable for mobile sensing applications.

Correlation between excited d-orbital electron lifetime in polaron dynamics and coloration of WO3 upon ultraviolet exposure

Science.gov (United States)

Lee, Young-Ahn; Han, Seung-Ik; Rhee, Hanju; Seo, Hyungtak

2018-05-01

Polarons have been suggested to explain the mechanism of the coloration of WO3 induced by UV light. However, despite the many experimental results that support small polarons as a key mechanism, direct observation of the carrier dynamics of polarons have yet to be reported. Here, we investigate the correlation between the electronic structure and the coloration of WO3 upon exposure to UV light in 5% H2/N2 gas and, more importantly, reveal photon-induced excited d-electron generation/relaxation via the W5+ oxidation state. The WO3 is fabricated by radio-frequency magnetron sputtering. X-ray diffraction patterns show that prepared WO3 is amorphous. Optical bandgap of 3.1 eV is measured by UV-vis before and after UV light. The results of Fourier transform infrared and Raman exhibit pristine WO3 is formed with surface H2O. The colored WO3 shows reduced state of W5+ state (34.3 eV) by using X-ray photoelectron spectroscopy. The valence band maximum of WO3 after UV light in H2 is shifted from mid gap to shallow donor by using ultraviolet photoelectron spectroscopy. During the exploration of the carrier dynamics, pump (700 nm)-probe (1000 nm) spectroscopy at the femtosecond scale was used. The results indicated that electron-phonon relaxation of UV-irradiated WO3, which is the origin of the polaron-induced local surface plasmonic effect, is dominant, resulting in slow decay (within a few picoseconds); in contrast, pristine WO3 shows fast decay (less than a picosecond). Accordingly, the long photoinduced carrier relaxation is ascribed to the prolonged hot-carrier lifetime in reduced oxides resulting in a greater number of free d-electrons and, therefore, more interactions with the W5+ sub-gap states.

Detectors in 3D available for assessment

CERN Document Server

Re, Valerio

2014-01-01

This deliverable reports on 3D devices resulting from the vertical integration of pixel sensors and readout electronics. After 3D integration steps such as etching of through-silicon vias and backside metallization of readout integrated circuits, ASICs and sensors are interconnected to form a 3D pixel detector. Various 3D detectors have been devised in AIDA WP3 and their status and performance is assessed here.

Electron-Impact Ionization and Dissociative Ionization of Biomolecules

Science.gov (United States)

Huo, Winifred M.; Chaban, Galina M.; Dateo, Christopher E.

2006-01-01

It is well recognized that secondary electrons play an important role in radiation damage to humans. Particularly important is the damage of DNA by electrons, potentially leading to mutagenesis. Molecular-level study of electron interaction with DNA provides information on the damage pathways and dominant mechanisms. Our study of electron-impact ionization of DNA fragments uses the improved binary-encounter dipole model and covers DNA bases, sugar phosphate backbone, and nucleotides. An additivity principle is observed. For example, the sum of the ionization cross sections of the separate deoxyribose and phosphate fragments is in close agreement with the C3(sup prime)- and C5 (sup prime)-deoxyribose-phospate cross sections, differing by less than 5%. Investigation of tandem double lesion initiated by electron-impact dissociative ionization of guanine, followed by proton reaction with the cytosine in the Watson-Crick pair, is currently being studied to see if tandem double lesion can be initiated by electron impact. Up to now only OH-induced tandem double lesion has been studied.

Cylindrical integrated optical microresonators: modeling by 3-D vectorial coupled mode theory

Czech Academy of Sciences Publication Activity Database

Stoffer, R.; Hiremath, K. R.; Hammer, M.; Prkna, Ladislav; Čtyroký, Jiří

2005-01-01

Roč. 256, 1/3 (2005), s. 46-67 ISSN 0030-4018 R&D Projects: GA ČR(CZ) GA102/05/0987 Grant - others:European Commission(XE) IST-2000-28018 NAIS Institutional research plan: CEZ:AV0Z20670512 Keywords : integrated optics * optical waveguide theory * modelling Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.456, year: 2005

Electronic structure of lanthanum calcium oxoborate LaCa4O(BO3)3

International Nuclear Information System (INIS)

Nelson, A.J.; Buuren, T. van; Willey, Trevor M.; Bostedt, C.; Adams, J.J.; Schaffers, K.I.; Terminello, Lou; Callcott, T.A.

2004-01-01

Lanthanum calcium oxoborate (LaCOB) is a nonlinear optical (NLO) material that belongs to the calcium-rare-earth (R) oxoborate family, with general composition Ca 4 RO(BO 3 ) 3 (R 3+ =La, Sm, Gd, Lu, Y). X-ray photoemission, photoabsorption, and resonant fluorescence were applied to study the electronic structure of this material. High resolution photoemission measurements on the valence band (VB) electronic structure and La 3d and 4d, Ca 2p, B 1s, and O 1s core lines were used to evaluate the surface and near surface chemistry. Element specific density of unoccupied electronic states in LaCOB were probed by X-ray absorption spectroscopy (XAS) at the La 3d (M 4,5 -edge), B 1s, and O 1s (K-edges) absorption edges. Soft X-ray fluorescence was used to further examine valence band states associated with spectral differences noted in the absorption measurements. These results provide the first measurements of the electronic structure and surface chemistry of this rare-earth oxoborate

Optimizing the 3D-reconstruction technique for serial block-face scanning electron microscopy.

Science.gov (United States)

Wernitznig, Stefan; Sele, Mariella; Urschler, Martin; Zankel, Armin; Pölt, Peter; Rind, F Claire; Leitinger, Gerd

2016-05-01

Elucidating the anatomy of neuronal circuits and localizing the synaptic connections between neurons, can give us important insights in how the neuronal circuits work. We are using serial block-face scanning electron microscopy (SBEM) to investigate the anatomy of a collision detection circuit including the Lobula Giant Movement Detector (LGMD) neuron in the locust, Locusta migratoria. For this, thousands of serial electron micrographs are produced that allow us to trace the neuronal branching pattern. The reconstruction of neurons was previously done manually by drawing cell outlines of each cell in each image separately. This approach was very time consuming and troublesome. To make the process more efficient a new interactive software was developed. It uses the contrast between the neuron under investigation and its surrounding for semi-automatic segmentation. For segmentation the user sets starting regions manually and the algorithm automatically selects a volume within the neuron until the edges corresponding to the neuronal outline are reached. Internally the algorithm optimizes a 3D active contour segmentation model formulated as a cost function taking the SEM image edges into account. This reduced the reconstruction time, while staying close to the manual reference segmentation result. Our algorithm is easy to use for a fast segmentation process, unlike previous methods it does not require image training nor an extended computing capacity. Our semi-automatic segmentation algorithm led to a dramatic reduction in processing time for the 3D-reconstruction of identified neurons. Copyright © 2016 Elsevier B.V. All rights reserved.

Poster - 38: On the physical and dosimetric properties of 3D printed electron bolus fabricated using polylactic acid

Energy Technology Data Exchange (ETDEWEB)

Sasaki, David; Jensen, Martin; Rickey, Daniel W; Dubey, Arbind; Harris, Chad; McCurdy, Boyd [CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba (Canada)

2016-08-15

Purpose: 3D printing technology could simplify and improve electron bolus fabrication. The purpose of this study was to characterize the density, dimensional accuracy, uniformity, and attenuation of PLA boluses fabricated with a low-cost 3D printer. Methods: Several solid square slabs were printed with specific requested dimensions and 100% infill using different fill patterns. These pieces were imaged using an x-ray flat panel imager in order to check for uniformity of the prints. Percentage depth doses (PDDs) were measured downstream of the slabs in solid water using a parallel plate chamber and compared to measurements in water in order to characterize attenuation. The dimensions of the PLA slabs were measured using digital calipers. The slabs were also weighed to find their density. Results: The fill pattern used to create boluses can affect the attenuation of the bolus. Fill patterns should be chosen carefully and quality assurance should be done for each printed piece. PLA causes the electron PDD to shift towards shallower depths, compared to water, by 1.7 mm for each centimeter of PLA. Agreement with design dimensions was within 1 mm in the plane of the printer bed, and within 1/3 of a millimeter (roughly the thickness of a single layer), perpendicular to the printer bed. Average density was in the range 1.20 – 1.22. Conclusions: 3D printing shows great promise for use in fabricating electron bolus. This work indicates that printed PLA can be a suitable material provided the increased attenuation is properly accounted for.

Poster - 38: On the physical and dosimetric properties of 3D printed electron bolus fabricated using polylactic acid

International Nuclear Information System (INIS)

Sasaki, David; Jensen, Martin; Rickey, Daniel W; Dubey, Arbind; Harris, Chad; McCurdy, Boyd

2016-01-01

Purpose: 3D printing technology could simplify and improve electron bolus fabrication. The purpose of this study was to characterize the density, dimensional accuracy, uniformity, and attenuation of PLA boluses fabricated with a low-cost 3D printer. Methods: Several solid square slabs were printed with specific requested dimensions and 100% infill using different fill patterns. These pieces were imaged using an x-ray flat panel imager in order to check for uniformity of the prints. Percentage depth doses (PDDs) were measured downstream of the slabs in solid water using a parallel plate chamber and compared to measurements in water in order to characterize attenuation. The dimensions of the PLA slabs were measured using digital calipers. The slabs were also weighed to find their density. Results: The fill pattern used to create boluses can affect the attenuation of the bolus. Fill patterns should be chosen carefully and quality assurance should be done for each printed piece. PLA causes the electron PDD to shift towards shallower depths, compared to water, by 1.7 mm for each centimeter of PLA. Agreement with design dimensions was within 1 mm in the plane of the printer bed, and within 1/3 of a millimeter (roughly the thickness of a single layer), perpendicular to the printer bed. Average density was in the range 1.20 – 1.22. Conclusions: 3D printing shows great promise for use in fabricating electron bolus. This work indicates that printed PLA can be a suitable material provided the increased attenuation is properly accounted for.

Embedding complex objects with 3d printing

KAUST Repository

Hussain, Muhammad Mustafa

2017-10-12

A CMOS technology-compatible fabrication process for flexible CMOS electronics embedded during additive manufacturing (i.e. 3D printing). A method for such a process may include printing a first portion of a 3D structure; pausing the step of printing the 3D structure to embed the flexible silicon substrate; placing the flexible silicon substrate in a cavity of the first portion of the 3D structure to embed the flexible silicon substrate in the 3D structure; and resuming the step of printing the 3D structure to form the second portion of the 3D structure.

New aspects of whistler waves driven by an electron beam studied by a 3-D electromagnetic code

Science.gov (United States)

Nishikawa, Ken-Ichi; Buneman, Oscar; Neubert, Torsten

1994-01-01

We have restudied electron beam driven whistler waves with a 3-D electromagnetic particle code. The simulation results show electromagnetic whistler wave emissions and electrostatic beam modes like those observed in the Spacelab 2 electron beam experiment. It has been suggested in the past that the spatial bunching of beam electrons associated with the beam mode may directly generate whistler waves. However, the simulation results indicate several inconsistencies with this picture: (1) whistler waves continue to be generated even after the beam mode space charge modulation looses its coherence, (2) the parallel (to the background magnetic field) wavelength of the whistler wave is longer than that of the beam instability, and (3) the parallel phase velocity of the whistler wave is smaller than that of the beam mode. The complex structure of the whistler waves in the vicinity of the beam suggest that the transverse motion (gyration) of the beam and background electrons is also involved in the generation of whistler waves.

Probing collective oscillation of d-orbital electrons at the nanoscale

Science.gov (United States)

Dhall, Rohan; Vigil-Fowler, Derek; Houston Dycus, J.; Kirste, Ronny; Mita, Seiji; Sitar, Zlatko; Collazo, Ramon; LeBeau, James M.

2018-02-01

Here, we demonstrate that high energy electrons can be used to explore the collective oscillation of s, p, and d orbital electrons at the nanometer length scale. Using epitaxial AlGaN/AlN quantum wells as a test system, we observe the emergence of additional features in the loss spectrum with the increasing Ga content. A comparison of the observed spectra with ab-initio theory reveals that the origin of these spectral features lies in excitations of 3d-electrons contributed by Ga. We find that these modes differ in energy from the valence electron plasmons in Al1-xGaxN due to the different polarizabilities of the d electrons. Finally, we study the dependence of observed spectral features on the Ga content, lending insights into the origin of these spectral features, and their coupling with electron-hole excitations.

Electron impact excitation of the lowest doublet and quartet core-excited autoionizing states in Rb atoms

International Nuclear Information System (INIS)

Borovik, A; Roman, V; Zatsarinny, O; Bartschat, K

2013-01-01

Electron impact excitation of the (4p 5 5s 2 ) 2 P 3/2,1/2 and (4p 5 4d5s) 4 P 1/2,3/2,5/2 autoionizing states in rubidium atoms was studied experimentally by measuring the ejected-electron excitation functions and theoretically by employing a fully relativistic Dirac B-spline R-matrix (close-coupling) model. The experimental data were collected in an impact energy range from the respective excitation thresholds up to 50 eV with an incident electron energy resolution of 0.2 eV and an observation angle of 54.7°. Absolute values of the excitation cross sections were obtained by normalizing to the theoretical predictions. The observed near-threshold resonance structures were also analysed by comparison with theory. For the 2 P 3/2,1/2 doublet states, a detailed analysis of the R-matrix results reveals that the most intense resonances are related to odd-parity negative-ion states with dominant configurations 4p 5 5s5p 2 and 4p 5 4d5s6s. The measured excitation functions for the 2 P 1/2 and 4 P J states indicate a noticeable cascade population due to the radiative decay from high-lying autoionizing states. A comparative analysis with similar data for other alkali atoms is also presented.

3D printed e-tongue

Science.gov (United States)

Gaál, Gabriel; da Silva, Tatiana A.; Gaál, Vladimir; Hensel, Rafael C.; Amaral, Lucas R.; Rodrigues, Varlei; Riul, Antonio

2018-05-01

Nowadays, one of the biggest issues addressed to electronic sensor fabrication is the build-up of efficient electrodes as an alternative way to the expensive, complex and multistage processes required by traditional techniques. Printed electronics arises as an interesting alternative to fulfill this task due to the simplicity and speed to stamp electrodes on various surfaces. Within this context, the Fused Deposition Modeling 3D printing is an emerging, cost-effective and alternative technology to fabricate complex structures that potentiates several fields with more creative ideas and new materials for a rapid prototyping of devices. We show here the fabrication of interdigitated electrodes using a standard home-made CoreXY 3D printer using transparent and graphene-based PLA filaments. Macro 3D printed electrodes were easily assembled within 6 minutes with outstanding reproducibility. The electrodes were also functionalized with different nanostructured thin films via dip-coating Layer-by-Layer technique to develop a 3D printed e-tongue setup. As a proof of concept, the printed e-tongue was applied to soil analysis. A control soil sample was enriched with several macro-nutrients to the plants (N, P, K, S, Mg and Ca) and the discrimination was done by electrical impedance spectroscopy of water solution of the soil samples. The data was analyzed by Principal Component Analysis and the 3D printed sensor distinguished clearly all enriched samples despite the complexity of the soil chemical composition. The 3D printed e-tongue successfully used in soil analysis encourages further investments in developing new sensory tools for precision agriculture and other fields exploiting the simplicity and flexibility offered by the 3D printing techniques.

Ce3+ 5d-centroid shift and vacuum referred 4f-electron binding energies of all lanthanide impurities in 150 different compounds

International Nuclear Information System (INIS)

Dorenbos, Pieter

2013-01-01

A review on the wavelengths of all five 4f–5d transitions for Ce 3+ in about 150 different inorganic compounds (fluorides, chlorides, bromides, iodides, oxides, sulfides, selenides, nitrides) is presented. It provides data on the centroid shift and the crystal field splitting of the 5d-configuration which are then used to estimate the Eu 2+ inter 4f-electron Coulomb repulsion energy U(6,A) in compound A. The four semi-empirical models (the redshift model, the centroid shift model, the charge transfer model, and the chemical shift model) on lanthanide levels that were developed past 12 years are briefly reviewed. It will be demonstrated how those models together with the collected data of this work and elsewhere can be united to construct schemes that contain the binding energy of electrons in the 4f and 5d states for each divalent and each trivalent lanthanide ion relative to the vacuum energy. As example the vacuum referred binding energy schemes for LaF 3 and La 2 O 3 will be constructed. - Highlights: ► An compilation on all five Ce 3+ 4f–5d energies in 150 inorganic compounds is presented. ► The relationship between the 5d centroid shift and host cation electronegativity id demonstrated. ► The electronic structure scheme of the lanthanides in La 2 O 3 and LaF 3 is presented.

High-Energy Impact Behaviors of Hybrid Composite Plates Strengthened with 3D-UHMWPE Composites

Directory of Open Access Journals (Sweden)

Sang-Youl Lee

2018-01-01

Full Text Available This study deals with drop-impact effects of new hybrid concrete plates strengthened with an ultrahigh molecular weight polyethylene (UHMWPE. The proposed 3D-UHMWPE results in excellent mechanical properties such as high abrasion resistance, impact strength, and low coefficient of friction. These special properties allow the product to be used in several high-performance applications. In this study, we used two kinds of high-performance materials for the impact reinforcement of a structure made of conventional materials such as a concrete. In particular, the impact mechanism of a fiber-concrete hybrid structure was studied using various parameters. The parametric studies are focused on the various effects of drop-impact on the structural performance. The combined effects of using different fiber-reinforced materials on the impact behavers are also investigated.

Universality of electron mobility in LaAlO3/SrTiO3 and bulk SrTiO3

Science.gov (United States)

Trier, Felix; Reich, K. V.; Christensen, Dennis Valbjørn; Zhang, Yu; Tuller, Harry L.; Chen, Yunzhong; Shklovskii, B. I.; Pryds, Nini

2017-08-01

Metallic LaAlO3/SrTiO3 (LAO/STO) interfaces attract enormous attention, but the relationship between the electron mobility and the sheet electron density, ns, is poorly understood. Here, we derive a simple expression for the three-dimensional electron density near the interface, n3 D , as a function of ns and find that the mobility for LAO/STO-based interfaces depends on n3 D in the same way as it does for bulk doped STO. It is known that undoped bulk STO is strongly compensated with N ≃5 ×1018 cm-3 background donors and acceptors. In intentionally doped bulk STO with a concentration of electrons n3 DN , the mobility collapses because scattering happens on n3 D intentionally introduced donors. For LAO/STO, the polar catastrophe which provides electrons is not supposed to provide an equal number of random donors and thus the mobility should be larger. The fact that the mobility is still the same implies that for the LAO/STO, the polar catastrophe model should be revisited.

3D Design Tools for Vacuum Electron Devices

International Nuclear Information System (INIS)

Levush, Baruch

2003-01-01

A reduction of development costs will have a significant impact on the total cost of the vacuum electron devices. Experimental testing cycles can be reduced or eliminated through the use of simulation-based design methodology, thereby reducing the time and cost of development. Moreover, by use of modern optimization tools for automating the process of seeking specific solution parameters and for studying dependencies of performance on parameters, new performance capabilities can be achieved, without resorting to expensive cycles of hardware fabrication and testing. Simulation-based-design will also provide the basis for sensitivity studies for determining the manufacturing tolerances associated with a particular design. Since material properties can have a critical effect on the performance of the vacuum electron devices, the design tools require precise knowledge of material characteristics, such as dielectric properties of the support rods, loss profile etc. Sensitivity studies must therefore include the effects of materials properties variation on device performance. This will provide insight for choosing the proper technological processes in order to achieve these tolerances, which is of great importance for achieving cost reduction. A successful design methodology depends on the development of accurate and efficient design tools with predictive capabilities. These design tools must be based on realistic models capable of high fidelity representation of geometry and materials, they must have optimization capabilities, and they must be easy to use

Performance of Hayabusa2 DCAM3-D Camera for Short-Range Imaging of SCI and Ejecta Curtain Generated from the Artificial Impact Crater Formed on Asteroid 162137 Ryugu (1999 JU3)

Science.gov (United States)

Ishibashi, K.; Shirai, K.; Ogawa, K.; Wada, K.; Honda, R.; Arakawa, M.; Sakatani, N.; Ikeda, Y.

2017-07-01

Deployable Camera 3-D (DCAM3-D) is a small high-resolution camera equipped on Deployable Camera 3 (DCAM3), one of the Hayabusa2 instruments. Hayabusa2 will explore asteroid 162137 Ryugu (1999 JU3) and conduct an impact experiment using a liner shooting device called Small Carry-on Impactor (SCI). DCAM3 will be detached from the Hayabusa2 spacecraft and observe the impact experiment. The purposes of the observation are to know the impact conditions, to estimate the surface structure of asteroid Ryugu, and to understand the physics of impact phenomena on low-gravity bodies. DCAM3-D requires high imaging performance because it has to image and detect multiple targets of different scale and radiance, i.e., the faint SCI before the shot from 1-km distance, the bright ejecta generated by the impact, and the asteroid. In this paper we report the evaluation of the performance of the CMOS imaging sensor and the optical system of DCAM3-D. We also describe the calibration of DCAM3-D. We confirmed that the imaging performance of DCAM3-D satisfies the required values to achieve the purposes of the observation.

Measurement of astrophysical S-factors and electron screening potentials for d(d,n)3He reaction in ZrD2, TiD2 and TaD0.5 targets in the ultralow energy region using plasma accelerator

International Nuclear Information System (INIS)

Bystritsky, V.M.; Bystritskii, Vit.M.; Dudkin, G.N.; Filipowicz, M.; Gazi, S.; Huran, J.; Kobzev, A.P.; Mesyats, G.A.; Nechaev, B.A.; Padalko, V.N.; Parzhitskii, S.S.; Pen'kov, F.M.; Philippov, A.V.; Kaminskii, V.L.; Tuleushev, Yu.Zh.; Wozniak, J.

2012-01-01

The present paper is devoted to the study of the electron screening effect influence on the rate of d(d,n) 3 He reaction in the ultralow deuteron collision energy range in the deuterated metals (ZrD 2 , TiD 2 and TaD 0.5 ). The ZrD 2 , TiD 2 and TaD0.5 targets were fabricated via magnetron sputtering of titanium, zirconium and tantalum in gas (deuterium) environment. The experiments have been carried out using the high-current pulsed Hall plasma accelerator (NSR TPU, Russia). The detection of neutrons with energy of 2.5 MeV from the dd reaction was done with plastic scintillation spectrometers. As a result of the experiments, the energy dependences of the astrophysical S-factor for the dd reaction in the deuteron collision energy range of 2-7 keV and the values of the electron screening potential U e of the interacting deuterons have been measured for the above targets: U e (ZrD 2 )=(205±35) eV; U e (TiD 2 )=(125±34) eV; U e (TaD 0.5 )=(313±58) eV. Our results are compared with the other published experimental and calculated data.

PHYSICS OF ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D

International Nuclear Information System (INIS)

PETTY, C.C.; PRATER, R.; LUCE, T.C.; ELLIS, R.A.; HARVEY, R.W.; KINSEY, J.E.; LAO, L.L.; LOHR, J.; MAKOWSKI, M.A.

2002-01-01

OAK A271 PHYSICS OF ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D. Recent experiments on the DIII-D tokamak have focused on determining the effect of trapped particles on the electron cyclotron current drive (ECCD) efficiency. The measured ECCD efficiency increases as the deposition location is moved towards the inboard midplane or towards smaller minor radius for both co and counter injection. The measured ECCD efficiency also increases with increasing electron density and/or temperature. The experimental ECCD is compared to both the linear theory (Toray-GA) as well as a quasilinear Fokker-Planck model (CQL3D). The experimental ECCD is found to be in better agreement with the more complete Fokker-Planck calculation, especially for cases of high rf power density and/or loop voltage

Utilization of Titanium Particle Impact Location to Validate a 3D Multicomponent Model for Cold Spray Additive Manufacturing

Science.gov (United States)

Faizan-Ur-Rab, M.; Zahiri, S. H.; King, P. C.; Busch, C.; Masood, S. H.; Jahedi, M.; Nagarajah, R.; Gulizia, S.

2017-12-01

Cold spray is a solid-state rapid deposition technology in which metal powder is accelerated to supersonic speeds within a de Laval nozzle and then impacts onto the surface of a substrate. It is possible for cold spray to build thick structures, thus providing an opportunity for melt-less additive manufacturing. Image analysis of particle impact location and focused ion beam dissection of individual particles were utilized to validate a 3D multicomponent model of cold spray. Impact locations obtained using the 3D model were found to be in close agreement with the empirical data. Moreover, the 3D model revealed the particles' velocity and temperature just before impact—parameters which are paramount for developing a full understanding of the deposition process. Further, it was found that the temperature and velocity variations in large-size particles before impact were far less than for the small-size particles. Therefore, an optimal particle temperature and velocity were identified, which gave the highest deformation after impact. The trajectory of the particles from the injection point to the moment of deposition in relation to propellant gas is visualized. This detailed information is expected to assist with the optimization of the deposition process, contributing to improved mechanical properties for additively manufactured cold spray titanium parts.

Method for dose-reduced 3D catheter tracking on a scanning-beam digital x-ray system using dynamic electronic collimation

Science.gov (United States)

Dunkerley, David A. P.; Funk, Tobias; Speidel, Michael A.

2016-03-01

Scanning-beam digital x-ray (SBDX) is an inverse geometry x-ray fluoroscopy system capable of tomosynthesis-based 3D catheter tracking. This work proposes a method of dose-reduced 3D tracking using dynamic electronic collimation (DEC) of the SBDX scanning x-ray tube. Positions in the 2D focal spot array are selectively activated to create a regionof- interest (ROI) x-ray field around the tracked catheter. The ROI position is updated for each frame based on a motion vector calculated from the two most recent 3D tracking results. The technique was evaluated with SBDX data acquired as a catheter tip inside a chest phantom was pulled along a 3D trajectory. DEC scans were retrospectively generated from the detector images stored for each focal spot position. DEC imaging of a catheter tip in a volume measuring 11.4 cm across at isocenter required 340 active focal spots per frame, versus 4473 spots in full-FOV mode. The dose-area-product (DAP) and peak skin dose (PSD) for DEC versus full field-of-view (FOV) scanning were calculated using an SBDX Monte Carlo simulation code. DAP was reduced to 7.4% to 8.4% of the full-FOV value, consistent with the relative number of active focal spots (7.6%). For image sequences with a moving catheter, PSD was 33.6% to 34.8% of the full-FOV value. The root-mean-squared-deviation between DEC-based 3D tracking coordinates and full-FOV 3D tracking coordinates was less than 0.1 mm. The 3D distance between the tracked tip and the sheath centerline averaged 0.75 mm. Dynamic electronic collimation can reduce dose with minimal change in tracking performance.

Embedding complex objects with 3d printing

KAUST Repository

Hussain, Muhammad Mustafa; Diaz, Cordero Marlon Steven

2017-01-01

A CMOS technology-compatible fabrication process for flexible CMOS electronics embedded during additive manufacturing (i.e. 3D printing). A method for such a process may include printing a first portion of a 3D structure; pausing the step

System Configuration and Operation Plan of Hayabusa2 DCAM3-D Camera System for Scientific Observation During SCI Impact Experiment

Science.gov (United States)

Ogawa, Kazunori; Shirai, Kei; Sawada, Hirotaka; Arakawa, Masahiko; Honda, Rie; Wada, Koji; Ishibashi, Ko; Iijima, Yu-ichi; Sakatani, Naoya; Nakazawa, Satoru; Hayakawa, Hajime

2017-07-01

An artificial impact experiment is scheduled for 2018-2019 in which an impactor will collide with asteroid 162137 Ryugu (1999 JU3) during the asteroid rendezvous phase of the Hayabusa2 spacecraft. The small carry-on impactor (SCI) will shoot a 2-kg projectile at 2 km/s to create a crater 1-10 m in diameter with an expected subsequent ejecta curtain of a 100-m scale on an ideal sandy surface. A miniaturized deployable camera (DCAM3) unit will separate from the spacecraft at about 1 km from impact, and simultaneously conduct optical observations of the experiment. We designed and developed a camera system (DCAM3-D) in the DCAM3, specialized for scientific observations of impact phenomenon, in order to clarify the subsurface structure, construct theories of impact applicable in a microgravity environment, and identify the impact point on the asteroid. The DCAM3-D system consists of a miniaturized camera with a wide-angle and high-focusing performance, high-speed radio communication devices, and control units with large data storage on both the DCAM3 unit and the spacecraft. These components were successfully developed under severe constraints of size, mass and power, and the whole DCAM3-D system has passed all tests verifying functions, performance, and environmental tolerance. Results indicated sufficient potential to conduct the scientific observations during the SCI impact experiment. An operation plan was carefully considered along with the configuration and a time schedule of the impact experiment, and pre-programed into the control unit before the launch. In this paper, we describe details of the system design concept, specifications, and the operating plan of the DCAM3-D system, focusing on the feasibility of scientific observations.

Electron paramagnetic resonance study of the Ce.sup.3+./sup. pair centers in YAlO.sub.3./sub.:Ce scintillator crystals

Czech Academy of Sciences Publication Activity Database

Buryi, Maksym; Laguta, Valentyn; Mihóková, Eva; Novák, Pavel; Nikl, Martin

2015-01-01

Roč. 92, č. 22 (2015), "224105-1"-"224105-10" ISSN 1098-0121 R&D Projects: GA MŠk LO1409; GA MŠk(CZ) LM2011029; GA ČR GAP204/12/0805 Grant - others:SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 Keywords : electron paramagnetic resonance * scintillator * pair of ions * density functional theory calculation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.736, year: 2014

Spin effects in medium-energy electron-3He scattering

International Nuclear Information System (INIS)

van den Brand, J.F.J.; Alarcon, R.; Bauer, T.

1998-01-01

New physics can be accessed by scattering polarized electrons from a polarized 3 He internal gas target. It is discussed how the asymmetries for the reactions 3 vector He(vector e,e'), 3 vector He(vector e,e'p), 3 vector He(vector e,e'n), 3 vector He(vector e,e'd), and 3 vector He(vector e,e'pn) may provide precise information on the S' and the D-wave parts of the 3 He ground-state wave function, the neutron form factors, and the role of spin-dependent reaction mechanism effects. The experiment uses up to 900 MeV (polarized) electrons from the AmPS storage ring in Amsterdam, Netherlands, in combination with large acceptance electron and hadron detectors. (orig.)

Production of H,D(2s, 2p) by electron impact (0 - 2000 eV) on simple hydrogen containing molecules, ch. 2, A2

International Nuclear Information System (INIS)

Moehlman, G.R.; Heer, F.J. de

1977-01-01

Absolute emission cross sections of Ly-α (H,D(2p → 1s)) radiation have been determined for 0 - 2000 eV electrons incident on H 2 , HD, HCl, H 2 O, NH 3 and CH 4 . By means of the application of electric quenching, the excitation cross sections of H,D(2s) could be obtained from the increase of the resulting Ly-α radiation for these molecules. Only in the case of electrons on H 2 , D 2 and HD was excitation of H,D(2s) found

Hyperfine structure in 5s4d 3D-5snf transitions of 87Sr

International Nuclear Information System (INIS)

Bushaw, B.A.; Kluge, H.J.; Lantzsch, J.; Schwalbach, R.; Stenner, J.; Stevens, H.; Wendt, K.; Zimmer, K.

1993-01-01

The hyperfine spectra of the 5s4d 3 D 1 -5s20f, 5s4d 3 D 2 -5s23f, and 5s4d 3 D 3 -5s32f transitions of 87 Sr (I=9/2) have been measured by collinear fast beam laser spectroscopy. The structure in the upper configurations is highly perturbed by fine structure splitting that is of comparable size to the hyperfine interaction energy. These perturbations can be adequately treated with conventional matrix diagonalization methods, using the 5s-electron magnetic dipole interaction term a 5s and the unperturbed fine structure splittings as input parameters. Additionally, hyperfine constants for the lower 5s4d 3 D configurations, including the A- and B-factors and a separation of the individual s- and d-electron contributions to these factors, are derived. (orig.)

TU-H-CAMPUS-TeP1-04: Novel 3D Printed Plastic Cutouts Filled with Aluminum Oxide for Same Day Electron Radiotherapy

International Nuclear Information System (INIS)

Mikell, J; Lee, C; Lam, K

2016-01-01

Purpose: Clinics that outsource electron cutout manufacturing may be unable to simulate and treat patients on the same day. To enable same day treatment, we investigate the use of 3D printed hollow cutouts filled with 30 grit Al_2O_3 powder. We verified the dosimetric equivalence of such a cutout relative to an outsourced Copper cutout. Methods: Printing was performed using a Ultibots Kossel 250 V-Slot 3D printer and polylactic acid filament. Printing files were derived from an in-house 3D model designed to mate with a Varian 6 cm electron cone. Relative to conventional cutouts (Copper or Cerrobend), the height of the hollow plastic cutout was extended by 1.0 cm to increase attenuation. Measurements were performed for 6 MeV in solid water at dmax (1.4 cm) with Gafchromic™ EBT3 film; the cutout was kidney-shaped with a long and short axis of approximately 5 and 2 cm, respectively. The Copper cutout was based on an outline of the 3D printed cutout.A calibration film was exposed immediately after the electron irradiations. All films, including an un-irradiated one, were from the same batch. Films were scanned on an Epson 10000XL flatbed scanner. Film analysis was performed in DoseLab (MOBIUS Medical Systems, Houston, Tx). Results: Visual comparison of the physical cutouts revealed that the Copper cutout had a slightly smaller opening than the printed cutout. Line profiles through the registered films indicated agreement within 5% in the open section. 99.9% of pixels passed gamma analysis with 2% local percent difference, 2 mm DTA, and a 25% threshold. Conclusion: Same day simulation and treatment with electrons is feasible with 3D printing of a hollow cutout filled with Al_2O_3. Future work will include evaluations of additional cutout shapes at different depths for higher energies. Other printing materials, such as bismuth, are being tested.

TU-H-CAMPUS-TeP1-04: Novel 3D Printed Plastic Cutouts Filled with Aluminum Oxide for Same Day Electron Radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Mikell, J; Lee, C; Lam, K [University of Michigan Health Systems, Ann Arbor, MI (United States)

2016-06-15

Purpose: Clinics that outsource electron cutout manufacturing may be unable to simulate and treat patients on the same day. To enable same day treatment, we investigate the use of 3D printed hollow cutouts filled with 30 grit Al{sub 2}O{sub 3} powder. We verified the dosimetric equivalence of such a cutout relative to an outsourced Copper cutout. Methods: Printing was performed using a Ultibots Kossel 250 V-Slot 3D printer and polylactic acid filament. Printing files were derived from an in-house 3D model designed to mate with a Varian 6 cm electron cone. Relative to conventional cutouts (Copper or Cerrobend), the height of the hollow plastic cutout was extended by 1.0 cm to increase attenuation. Measurements were performed for 6 MeV in solid water at dmax (1.4 cm) with Gafchromic™ EBT3 film; the cutout was kidney-shaped with a long and short axis of approximately 5 and 2 cm, respectively. The Copper cutout was based on an outline of the 3D printed cutout.A calibration film was exposed immediately after the electron irradiations. All films, including an un-irradiated one, were from the same batch. Films were scanned on an Epson 10000XL flatbed scanner. Film analysis was performed in DoseLab (MOBIUS Medical Systems, Houston, Tx). Results: Visual comparison of the physical cutouts revealed that the Copper cutout had a slightly smaller opening than the printed cutout. Line profiles through the registered films indicated agreement within 5% in the open section. 99.9% of pixels passed gamma analysis with 2% local percent difference, 2 mm DTA, and a 25% threshold. Conclusion: Same day simulation and treatment with electrons is feasible with 3D printing of a hollow cutout filled with Al{sub 2}O{sub 3}. Future work will include evaluations of additional cutout shapes at different depths for higher energies. Other printing materials, such as bismuth, are being tested.

Production of H, D (2s, 2p) by electron impact (0-2000 eV) on simple hydrogen containing molecules

International Nuclear Information System (INIS)

Moehlmann, G.R.; Shima, K.H.; Heer, F.J. de

1978-01-01

Absolute emission cross sections of Ly-α (H, D (2p → 1s)) radiation have been determined for 0-2000 eV electrons incident on H 2 , HD, D 2 , HCl, H 2 O, NH 3 and CH 4 . By means of the application of electric quenching the excitation cross sections of H, D (2s) could be obtained from the increase of the resulting Ly-α radiation for these molecules. It was found that only for H 2 , HD and D 2 fragments in the H (2s) state are formed. (Auth.)

Recognition of Symmetric 3D Bodies

Czech Academy of Sciences Publication Activity Database

Suk, Tomáš; Flusser, Jan

2014-01-01

Roč. 6, č. 3 (2014), s. 722-757 ISSN 2073-8994 R&D Projects: GA ČR GAP103/11/1552 Institutional support: RVO:67985556 Keywords : rotation symmetry * reflection symmetry * 3D complex moments * 3D rotation invariants Subject RIV: JD - Computer Applications, Robotics Impact factor: 0.826, year: 2014 http://library.utia.cas.cz/separaty/2014/ZOI/suk-0431156.pdf

Vibrational excitation of D2 by low energy electrons

International Nuclear Information System (INIS)

Buckman, S.J.; Phelps, A.V.

1985-01-01

Excitation coefficients for the production of vibrationally exicted D 2 by low energy electrons have been determined from measurements of the intensity of infrared emission from mixtures of D 2 and small concentrations of CO 2 or CO. The measurements were made using the electron drift tube technique and covered electric field to gas density ratios (E/n) from (5 to 80) x 10 -21 V m 2 , corresponding to mean electron energies between 0.45 and 4.5 eV. The CO 2 and CO concentrations were chosen to allow efficient excitation transfer from the D 2 to the carbon containing molecule, but to minimize direct excitation of the CO 2 or CO. The measured infrared intensities were normalized to predicted values for N 2 --CO 2 and N 2 --CO mixtures at E/n where the efficiency of vibrational excitation is known to be very close to 100%. The experimental excitation coefficients are in satisfactory agreement with predictions based on electron--D 2 cross sections at mean electron energies below 1 eV, but are about 50% too high at mean energies above about 2 eV. Application of the technique to H 2 did not yield useful vibrational excitation coefficients. The effective coefficients in H 2 --CO 2 mixtures were a factor of about 3 times the predicted values. For our H 2 --CO mixtures the excitation of CO via excitation transfer from H 2 is small compared to direct electron excitation of CO molecules. Published experiments and theories on electron--H 2 and electron--D 2 collisions are reviewed to obtain the cross sections used in the predictions

Electron-impact excitation of the In+ ion resonance line

International Nuclear Information System (INIS)

Gomonai, A.; OvcharenkO, E.; Imre, A.; Hutych, Yu.

2004-01-01

Full text: Study of the electron-impact excitation of the In + ion is important not only for atomic structure research, but also for applications to astrophysics, analytical techniques and fusion research, as well as for new applications of this ion such as a component of solid state laser media and as a source for an optical frequency standart. The energy dependence of the electron-impact excitation of the In + ion resonance line was studied by spectroscopic method using the crossed-beam technique in the energy range from the threshold up to 300 eV for the following process: e + In + (4d 10 5s 2 ) 1 S 0 e' + In + (4d 10 5s5p) 1 P 0 1 e' + In + (4d 10 5s 2 ) 1 S 0 +h (1) Process (1) includes the direct electron-impact excitation of the 5s5p 1 P 0 1 state from the ground 5s 2 1 S 0 state, as well as the contribution of the cascade transitions and resonance processes: In + (4d 10 5s nln 1 l 1 , 4d 10 5p 2 nl, 4d 9 5s 2 nln 1 l 1 ) In + (4d 10 5s 2 ) 1 S 0 + e' (2) The peculiarity of this investigation is the presence of low lying metastable states and high temperature (T1250K) of atomic vapour. The ions produced in the ion source on the heated tantalum surface were extracted, focused and accelerated by a system of ion optical lenses into a beam (E i = 700eV, I i (11.4)10 -6 A), separated from neutral atoms by means of a 90 deg electrostatic selector and crossed at the right angle by the ribbon electron beam (E e = (7300)eV, Ie = (610)10 -5 A, 0 1/2 (0.40.5)eV) in the collision region (at P 10 -8 Torr) [1]. Radiation observed at 90 deg with respect to the beam intersection plane was spectrally separated by a 70 deg vacuum monochromator (d/dl = 1.7nm/mm) based on the Seya- Namioka scheme and detected by a photomultiplier. The measurements and experimental data processing were realised by means of a PC. The drop of the energy dependence of the excitation cross section obey the E -1 lnE rule specific for the optically allow transitions. A distinct structure in the energy

Electron-impact excitation of multiply-charged ions using energy loss in merged beams: e + Si3+(3s2S1/2) → e + Si3+(3p2P1/2,3/2)

International Nuclear Information System (INIS)

Wahlin, E.K.; Thompson, J.S.; Dunn, G.H.; Phaneuf, R.A.; Gregory, D.C.; Smith, A.C.H.

1990-01-01

For the first time absolute total cross sections for electron-impact excitation of a multiply-charged ion have been measured using an electron-energy-loss technique. Measurements were made near threshold for the process e + Si 3+ (3s 2 S 1/2 ) → e + Si 3+ (3p 2 P 1/2 , 3/2 ) -- 8.88 eV. The 10 -15 cm 2 measured cross section agrees with results of 7-state close coupling calculations to better than the ±20% (90% CL) total uncertainty of the measurements. Convoluting the theoretical curve with a Gaussian energy distribution indicates an energy width of 0.15 approx-lt ΔE approx-lt 0.20 eV. 12 refs., 2 figs

Sci—Thur AM: YIS - 07: Design and production of 3D printed bolus for electron radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Su, Shiqin [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia (Canada); Moran, Kathryn [Queen Elizabeth II Health Sciences Centre, Nova Scotia Cancer Centre, Halifax, Nova Scotia (Canada); Robar, James L. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia (Canada); Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia (Canada)

2014-08-15

This is a proof-of-concept study demonstrating the capacity for modulated electron radiation therapy (MERT) using 3D printed bolus. Previous reports have involved bolus design using an electron pencil beam model and fabrication using a milling machine. In this study, an in-house algorithm is presented that optimizes the dose distribution with regard to dose coverage, conformity and homogeneity within planning target volume (PTV). The algorithm uses calculated result of a commercial electron Monte Carlo dose calculation as input. Distances along ray lines from distal side of 90% isodose to distal surface of PTV are used to estimate the bolus thickness. Inhomogeneities within the calculation volume are accounted for using coefficient of equivalent thickness method. Several regional modulation operators are applied to improve dose coverage and uniformity. The process is iterated (usually twice) until an acceptable MERT plan is realized, and the final bolus is printed using solid polylactic acid. The method is evaluated with regular geometric phantoms, anthropomorphic phantoms and a clinical rhabdomyosarcoma pediatric case. In all cases the dose conformity is improved compared to that with uniform bolus. The printed boluses conform well to the surface of complex anthropomorphic phantoms. For the rhabdomyosarcoma patient, the MERT plan yields a reduction of mean dose by 38.2% in left kidney relative to uniform bolus. MERT using 3D printed bolus appears to be a practical, low cost approach to generating optimized bolus for electron therapy. The method is effective in improving conformity of prescription isodose surface and in sparing immediately adjacent normal tissues.

Sci—Thur AM: YIS - 07: Design and production of 3D printed bolus for electron radiation therapy

International Nuclear Information System (INIS)

Su, Shiqin; Moran, Kathryn; Robar, James L.

2014-01-01

This is a proof-of-concept study demonstrating the capacity for modulated electron radiation therapy (MERT) using 3D printed bolus. Previous reports have involved bolus design using an electron pencil beam model and fabrication using a milling machine. In this study, an in-house algorithm is presented that optimizes the dose distribution with regard to dose coverage, conformity and homogeneity within planning target volume (PTV). The algorithm uses calculated result of a commercial electron Monte Carlo dose calculation as input. Distances along ray lines from distal side of 90% isodose to distal surface of PTV are used to estimate the bolus thickness. Inhomogeneities within the calculation volume are accounted for using coefficient of equivalent thickness method. Several regional modulation operators are applied to improve dose coverage and uniformity. The process is iterated (usually twice) until an acceptable MERT plan is realized, and the final bolus is printed using solid polylactic acid. The method is evaluated with regular geometric phantoms, anthropomorphic phantoms and a clinical rhabdomyosarcoma pediatric case. In all cases the dose conformity is improved compared to that with uniform bolus. The printed boluses conform well to the surface of complex anthropomorphic phantoms. For the rhabdomyosarcoma patient, the MERT plan yields a reduction of mean dose by 38.2% in left kidney relative to uniform bolus. MERT using 3D printed bolus appears to be a practical, low cost approach to generating optimized bolus for electron therapy. The method is effective in improving conformity of prescription isodose surface and in sparing immediately adjacent normal tissues

Effective sensitivity in 3D PET: The impact of detector dead time on 3D system performance

International Nuclear Information System (INIS)

Bailey, D.L.; Jones, T.; Meikle, S.R.

1996-01-01

3D PET has higher sensitivity than 2D PET. Sensitivity is determined by two components: the geometric solid angle for detection, and the fractional dead time, i.e., the time for which the detector is unavailable for accepting events. The loss in overall sensitivity as a function of radioactivity concentration due to these factors for 3D PET has been characterized by a parameter, the effective sensitivity, which combines absolute sensitivity and noise equivalent count rates. This parameter includes scatter, system sensitivity, dead time, and random coincidence rates, and permits comparisons between different tomographs as well as the same tomograph under different conditions. Effective sensitivity decreases most rapidly for larger, open 3D tomographs. The loss in effective sensitivity with increasing count rate suggests that new faster scintillation detectors will be needed to realize the sensitivity gain of 3D PET over a wide dynamic range of radioactivity concentrations

Usage of 3D models of tetralogy of Fallot for medical education: impact on learning congenital heart disease.

Science.gov (United States)

Loke, Yue-Hin; Harahsheh, Ashraf S; Krieger, Axel; Olivieri, Laura J

2017-03-11

Congenital heart disease (CHD) is the most common human birth defect, and clinicians need to understand the anatomy to effectively care for patients with CHD. However, standard two-dimensional (2D) display methods do not adequately carry the critical spatial information to reflect CHD anatomy. Three-dimensional (3D) models may be useful in improving the understanding of CHD, without requiring a mastery of cardiac imaging. The study aimed to evaluate the impact of 3D models on how pediatric residents understand and learn about tetralogy of Fallot following a teaching session. Pediatric residents rotating through an inpatient Cardiology rotation were recruited. The sessions were randomized into using either conventional 2D drawings of tetralogy of Fallot or physical 3D models printed from 3D cardiac imaging data sets (cardiac MR, CT, and 3D echocardiogram). Knowledge acquisition was measured by comparing pre-session and post-session knowledge test scores. Learner satisfaction and self-efficacy ratings were measured with questionnaires filled out by the residents after the teaching sessions. Comparisons between the test scores, learner satisfaction and self-efficacy questionnaires for the two groups were assessed with paired t-test. Thirty-five pediatric residents enrolled into the study, with no significant differences in background characteristics, including previous clinical exposure to tetralogy of Fallot. The 2D image group (n = 17) and 3D model group (n = 18) demonstrated similar knowledge acquisition in post-test scores. Residents who were taught with 3D models gave a higher composite learner satisfaction scores (P = 0.03). The 3D model group also had higher self-efficacy aggregate scores, but the difference was not statistically significant (P = 0.39). Physical 3D models enhance resident education around the topic of tetralogy of Fallot by improving learner satisfaction. Future studies should examine the impact of models on teaching CHD that

3-D conformal radiation therapy - Part I: Treatment planning

International Nuclear Information System (INIS)

Burman, Chandra M.; Mageras, Gikas S.

1997-01-01

Objective: In this presentation we will look into the basic components of 3-dimensional conformal treatment planning, and will discuss planning for some selected sites. We will also review some current and future trends in 3-D treatment planning. External beam radiation therapy is one of the arms of cancer treatment. In the recent years 3-D conformal therapy had significant impact on the practice of external beam radiation therapy. Conformal radiation therapy shapes the high-dose volume so as to conform to the target volume while minimizing the dose to the surrounding normal tissues. The advances that have been achieved in conformal therapy are in part due to the development of 3-D treatment planning, which in turn has capitalized on 3-D imaging for tumor and normal tissue localization, as well as on available computational power for the calculation of 3-D dose distributions, visualization of anatomical and dose volumes, and numerical evaluation of treatment plans. In this course we will give an overview of how 3-D conformal treatments are designed and transferred to the patient. Topics will include: 1) description of the major components of a 3-D treatment planning system, 2) techniques for designing treatments, 3) evaluation of treatment plans using dose distribution displays, dose-volume histograms and normal tissue complication probabilities, 4) implementation of treatments using shaped blocks and multileaf collimators, 5) verification of treatment delivery using portal films and electronic portal imaging devices. We will also discuss some current and future trends in 3-D treatment planning, such as field shaping with multileaf collimation, computerized treatment plan optimization, including the use of nonuniform beam profiles (intensity modulation), and incorporating treatment uncertainties due to patient positioning errors and organ motion into treatment planning process

ELECTRON CYCLOTRON CURRENT DRIVE IN DIII-D: EXPERIMENT AND THEORY

International Nuclear Information System (INIS)

PRATER, R; PETTY, CC; LUCE, TC; HARVEY, RW; CHOI, M; LAHAYE, RJ; LIN-LIU, Y-R; LOHR, J; MURAKAMI, M; WADE, MR; WONG, K-L

2003-01-01

A271 ELECTRON CYCLOTRON CURRENT DRIVE IN DIII-D: EXPERIMENT AND THEORY. Experiments on the DIII-D tokamak in which the measured off-axis electron cyclotron current drive has been compared systematically to theory over a broad range of parameters have shown that the Fokker-Planck code CQL3D provides an excellent model of the relevant current drive physics. This physics understanding has been critical in optimizing the application of ECCD to high performance discharges, supporting such applications as suppression of neoclassical tearing modes and control and sustainment of the current profile

The « 3-D donut » electrostatic analyzer for millisecond timescale electron measurements in the solar wind

Science.gov (United States)

Berthomier, M.; Techer, J. D.

2017-12-01

Understanding electron acceleration mechanisms in planetary magnetospheres or energy dissipation at electron scale in the solar wind requires fast measurement of electron distribution functions on a millisecond time scale. Still, since the beginning of space age, the instantaneous field of view of plasma spectrometers is limited to a few degrees around their viewing plane. In Earth's magnetosphere, the NASA MMS spacecraft use 8 state-of-the-art sensor heads to reach a time resolution of 30 milliseconds. This costly strategy in terms of mass and power consumption can hardly be extended to the next generation of constellation missions that would use a large number of small-satellites. In the solar wind, using the same sensor heads, the ESA THOR mission is expected to reach the 5ms timescale in the thermal energy range, up to 100eV. We present the « 3-D donut » electrostatic analyzer concept that can change the game for future space missions because of its instantaneous hemispheric field of view. A set of 2 sensors is sufficient to cover all directions over a wide range of energy, e.g. up to 1-2keV in the solar wind, which covers both thermal and supra-thermal particles. In addition, its high sensitivity compared to state of the art instruments opens the possibility of millisecond time scale measurements in space plasmas. With CNES support, we developed a high fidelity prototype (a quarter of the full « 3-D donut » analyzer) that includes all electronic sub-systems. The prototype weights less than a kilogram. The key building block of the instrument is an imaging detector that uses EASIC, a low-power front-end electronics that will fly on the ESA Solar Orbiter and on the NASA Parker Solar Probe missions.

3D background aerodynamics using CFD

Energy Technology Data Exchange (ETDEWEB)

Soerensen, N.N.

2002-11-01

3D rotor computations for the Greek Geovilogiki (GEO) 44 meter rotor equipped with 19 meters blades are performed. The lift and drag polars are extracted at five spanvise locations r/R= (.37, .55, .71, .82, .93) based on identification of stagnation points between 2D and 3D computations. The inner most sections shows clear evidence of 3D radial pumping, with increased lift compared to 2D values. In contrast to earlier investigated airfoils a very limited impact on the drag values are observed. (au)

3D background aerodynamics using CFD

DEFF Research Database (Denmark)

Sørensen, Niels N.

2002-01-01

3D rotor computations for the Greek Geovilogiki (GEO) 44 meter rotor equipped with 19 meters blades are performed. The lift and drag polars are extracted at five spanvise locations r/R= (.37, .55, .71, .82, .93) based on identification of stagnationpoints between 2D and 3D computations. The inner...... most sections shows clear evidence of 3D radial pumping, with increased lift compared to 2D values. In contrast to earlier investigated airfoils a very limited impact on the drag values are observed....

Electron impact spectra of methane, ethane, and neopentane

International Nuclear Information System (INIS)

Johnson, K.E.; Kim, K.; Johnston, D.B.; Lipsky, S.

1979-01-01

Electron impact spectra of methane, ethane, and neopentane have been obtained at scattering angles of 0 0 and 90 0 and at impact energies from approx. =30 to 250 eV. The data are consistent with the lowest excitation in all of these systems to involve promotion of an electron to a 3s Rydberg-like orbital. Differences between 0 0 and 90 0 onsets are attributed to large-angle intensity enhancements of transitions to the 3s Rydberg triplets. At 90 0 all of the spectra exhibit very similar intensity redistributions with strong enhancement of transitions in the 12 and 15 eV region as compared to lower-lying transitions. Assignments of the spectra and possible origins of the angular dependence are discussed

The fabrication of 3-D nanostructures by a low- voltage EBL

Energy Technology Data Exchange (ETDEWEB)

Oh, Seung Hun [Department of Nano Science and Technology, Pusan National University (Korea, Republic of); Kim, Jae Gu [Department of Nano-Mechanical Systems, Korea Institute of Machinery and Materials (Korea, Republic of); Kim, Chang Seok [Department of Cogno-Mechatronics Engineering, Pusan National University (Korea, Republic of); Choi, Doo Sun; Chang, Sunghwan [Department of Nano-Mechanical Systems, Korea Institute of Machinery and Materials (Korea, Republic of); Jeong, Myung Yung, E-mail: myjeong@pusan.ac.kr [Department of Cogno-Mechatronics Engineering, Pusan National University (Korea, Republic of)

2011-02-15

Three-dimensional (3-D) structures are used in many applications, including the fabrication of opto-electronic and bio-MEMS devices. Among the various fabrication techniques available for 3-D structures, nano imprint lithography (NIL) is preferred for producing nanoscale 3-D patterns because of its simplicity, relatively short processing time, and high manufacturing precision. For efficient replication in NIL, a precise 3-D stamp must be used as an imprinting tool. Hence, we attempted the fabrication of original 3-D master molds by low-voltage electron beam lithography (EBL). We then fabricated polydimethylsiloxane (PDMS) stamps from the original 3-D mold via replica molding with ultrasonic vibration.First, we experimentally analyzed the characteristics of low-voltage EBL in terms of various parameters such as resist thickness, acceleration voltage, aperture size, and baking temperature. From these e-beam exposure experiments, we found that the exposure depth and width were almost saturated at 3 kV or lesser, even when the electron dosage was increased. This allowed for the fabrication of various stepped 3-D nanostructures at a low voltage. In addition, by using line-dose EBL, V-groove patterns could be fabricated on a cured electron resist (ER) at a low voltage and low baking temperature. Finally, the depth variation could be controlled to within 10 nm through superposition exposure at 1 kV. From these results, we determined the optimum electron beam exposure conditions for the fabrication of various 3-D structures on ERs by low-voltage EBL. We then fabricated PDMS stamps via the replica molding process.

Level excitation cross sections of Si I fragments produced by 100 eV electron impact on SiH4

International Nuclear Information System (INIS)

Sato, T.; Kono, A.; Goto, T.

1988-01-01

The fluorescence decay Si I atomic lines after electron impact excitation of SiH 4 molecular gas was observed, and the level excitation cross sections (LECS) of Si I fragments were determined by separating the contribution from cascade transitions to line emissions. Observed transitions were 4s 1 P--3p 2 1 D, 4s 3 P--3p 2 3 P, 3d 1 P--3p 2 1 S, 3d 1 D--3p 2 1 D, 3d 1 F--3p 2 1 D, 3d 3 P--3p 2 3 P, and 3p 3 3 D--3p 2 3 P, for which the LECSs of the upper levels were determined at 100 eV excitation energy. The contribution of the direct excitations to these line emissions were found to range from 37% to 80%. Analysis of the 4s 1 P--3p 2 1 D decay curve also gave the LECSs of the cascading levels 4p 1 P, 4p 1 S, and 4p 1 D. Also obtained were some radiative lifetimes not reported before

Electron impact spectra of some mono-olefinic hydrocarbonsa)

International Nuclear Information System (INIS)

Johnson, K.E.; Johnston, D.B.; Lipsky, S.

1979-01-01

Electron impact spectra of ethylene, propylene, isobutene, trans-butene, cis-butene, trimethylethylene, and tetramethylethylene have been obtained at scattering angles of 0 0 and 90 0 and at impact energies from approx. =20 to 150 eV. The spectra scan an energy-loss region from 2.5--15 eV. All of the observed Rydberg transitions of the methyl derivatives are correlated to corresponding Rydberg transitions of ethylene. The missing π→3p transitions of ethylene are tentatively located via this correlation. Evidence is also presented for assigning the N→3R' system of ethylene (at 8.26 eV) to a π→3p/sub x/ transition. Possible assignments of some broad continua above approx. =8--9eV as sigma→π* and sigma→sigma* transitions are considered. In agreement with other reported large-angle electron impact spectra, no evidence is obtained for transitions that could be assigned to triplet Rydberg states. However the π→π* triplet transitions are all clearly located with transition energies in good agreement with those obtained by a variety of other techniques

Experimental system to measure excitation cross-sections by electron impact. Measurements for ArI and ArII

International Nuclear Information System (INIS)

Blanco, F.; Sanchez, J.A.; Aguilera, J.A.; Campos, J.

1989-01-01

An experimental set-up to measure excitation cross-section of atomic and molecular levels by electron impact based on the optical method is reported. We also present some measurements on the excitation cross-section for ArI 5p'(1/2)0 level, and for simultaneous ionization and excitation of Ar leading to ArII levels belonging to the 3p 4 4p and 3p 4 4d configurations. (Author)

Comparison of 3D cellular imaging techniques based on scanned electron probes: Serial block face SEM vs. Axial bright-field STEM tomography.

Science.gov (United States)

McBride, E L; Rao, A; Zhang, G; Hoyne, J D; Calco, G N; Kuo, B C; He, Q; Prince, A A; Pokrovskaya, I D; Storrie, B; Sousa, A A; Aronova, M A; Leapman, R D

2018-06-01

Microscopies based on focused electron probes allow the cell biologist to image the 3D ultrastructure of eukaryotic cells and tissues extending over large volumes, thus providing new insight into the relationship between cellular architecture and function of organelles. Here we compare two such techniques: electron tomography in conjunction with axial bright-field scanning transmission electron microscopy (BF-STEM), and serial block face scanning electron microscopy (SBF-SEM). The advantages and limitations of each technique are illustrated by their application to determining the 3D ultrastructure of human blood platelets, by considering specimen geometry, specimen preparation, beam damage and image processing methods. Many features of the complex membranes composing the platelet organelles can be determined from both approaches, although STEM tomography offers a higher ∼3 nm isotropic pixel size, compared with ∼5 nm for SBF-SEM in the plane of the block face and ∼30 nm in the perpendicular direction. In this regard, we demonstrate that STEM tomography is advantageous for visualizing the platelet canalicular system, which consists of an interconnected network of narrow (∼50-100 nm) membranous cisternae. In contrast, SBF-SEM enables visualization of complete platelets, each of which extends ∼2 µm in minimum dimension, whereas BF-STEM tomography can typically only visualize approximately half of the platelet volume due to a rapid non-linear loss of signal in specimens of thickness greater than ∼1.5 µm. We also show that the limitations of each approach can be ameliorated by combining 3D and 2D measurements using a stereological approach. Copyright © 2018. Published by Elsevier Inc.

Electron impact ionization of heavy ions: some surprises

International Nuclear Information System (INIS)

Younger, S.M.

1986-01-01

This paper reports the results of calculations of electron impact ionization cross sections for a variety of heavy ions using a distorted wave Born-exchange approximation. The target is described by a Hartree-Fock wavefunction. The scattering matrix element is represented by a triple partial wave expansion over incident, scattered, and ejected (originally bound) continuum states. These partial waves are computed in the potentials associated with the initial target (incident and scattered waves) and the residual ion (ejected waves). A Gauss integration was performed over the distribution of energy between the two final state continuum electrons. For ionization of closed d- and f-subshells, the ejected f-waves were computed in frozen-core term-dependent Hartree-Fock potentials, which include the strong repulsive contribution in singlet terms which arises from the interaction of an excited orbital with an almost closed shell. Ground state correlation was included in some calculations of ionization of d 10 subshells

PF2fit: Polar Fast Fourier Matched Alignment of Atomistic Structures with 3D Electron Microscopy Maps.

Directory of Open Access Journals (Sweden)

Radhakrishna Bettadapura

2015-10-01

Full Text Available There continue to be increasing occurrences of both atomistic structure models in the PDB (possibly reconstructed from X-ray diffraction or NMR data, and 3D reconstructed cryo-electron microscopy (3D EM maps (albeit at coarser resolution of the same or homologous molecule or molecular assembly, deposited in the EMDB. To obtain the best possible structural model of the molecule at the best achievable resolution, and without any missing gaps, one typically aligns (match and fits the atomistic structure model with the 3D EM map. We discuss a new algorithm and generalized framework, named PF(2 fit (Polar Fast Fourier Fitting for the best possible structural alignment of atomistic structures with 3D EM. While PF(2 fit enables only a rigid, six dimensional (6D alignment method, it augments prior work on 6D X-ray structure and 3D EM alignment in multiple ways: Scoring. PF(2 fit includes a new scoring scheme that, in addition to rewarding overlaps between the volumes occupied by the atomistic structure and 3D EM map, rewards overlaps between the volumes complementary to them. We quantitatively demonstrate how this new complementary scoring scheme improves upon existing approaches. PF(2 fit also includes two scoring functions, the non-uniform exterior penalty and the skeleton-secondary structure score, and implements the scattering potential score as an alternative to traditional Gaussian blurring. Search. PF(2 fit utilizes a fast polar Fourier search scheme, whose main advantage is the ability to search over uniformly and adaptively sampled subsets of the space of rigid-body motions. PF(2 fit also implements a new reranking search and scoring methodology that considerably improves alignment metrics in results obtained from the initial search.

3D Printed Bionic Ears

Science.gov (United States)

Mannoor, Manu S.; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A.; Soboyejo, Winston O.; Verma, Naveen; Gracias, David H.; McAlpine, Michael C.

2013-01-01

The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the precise anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

3D printed bionic ears.

Science.gov (United States)

Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

2013-06-12

The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.

Coplanar asymmetric angles and symmetric energy sharing triple differential cross sections for 200 eV electron-impact ionization of Ar (3p)

International Nuclear Information System (INIS)

Ozer, Zehra N; Varol, Onur; Yavuz, Murat; Dogan, Mevlut; Amami, Sadek; Madison, Don

2015-01-01

We have measured triple differential cross sections (TDCSs) for electron-impact ionization of the 3p shell of Ar at 200 eV incident electron energy. The experiments have been performed in coplanar asymmetric energy sharing geometry. The experimental results are compared with the theoretical models of three body distorted wave (3DW) and distorted wave Born approximation (DWBA). (paper)

Modelling and observation of heat losses from buildings : The impact of geometric detail on 3D heat flux modelling

NARCIS (Netherlands)

Lee, D.; Pietrzyk, P.; Donkers, S.; Liem, V.; van Oostveen, J.; Montazeri, S.; Boeters, R.; Colin, J.; Kastendeuch, P.; Nerry, F.; Menenti, M.; Gorte, B.G.H.; Verbree, E.

2013-01-01

The impact of 3D geometry complexity on the accuracy of simulating radiative, convective and conductive fluxes in an urban canyon was explored. The research involved the collection of meteorological data in an urban canyon in the city of Strasbourg, France, for input into a 3D model called LASER/F,

Controlled Confinement of Half-metallic 2D Electron Gas in BaTiO3/Ba2FeReO6/BaTiO3 Heterostructures: A First-principles Study

Science.gov (United States)

Saha-Dasgupta, Tanusri; Baidya, Santu; Waghmare, Umesh; Paramekanti, Arun

Using density functional theory calculations, we establish that the half-metallicity of bulk Ba2FeReO6 survives down i to 1 nm thickness in BaTiO3/Ba2FeReO6/BaTiO3 heterostructures grown along the (001) and (111) directions. The confinement of the two-dimensional (2D) electron gas in this quantum well structure arises from the suppressed hybridization between Re/Fe d states and unoccupied Ti d states, and it is further strengthened by polar fields for the (111) direction. This mechanism, distinct from the polar catastrophe, leads to an order of magnitude stronger confinement of the 2D electron gas than that at the LaAlO3/SrTiO3 interface. We further show low-energy bands of (111) heterostructure display nontrivial topological character. Our work opens up the possibility of realizing ultra-thin spintronic devices. Journal Ref: Phys. Rev. B 92, 161106(R) (2015) S.B. and T.S.D thank Department of Science and Technology, India for the support through Thematic Unit of Excellence. AP was supported by NSERC (Canada).

An environmental impact assessment system for agricultural R and D

International Nuclear Information System (INIS)

Rodrigues, Geraldo Stachetti; Campanhola, Clayton; Kitamura, Paulo Choji

2003-01-01

A strategic planning process has been implemented at the Brazilian Agricultural Research Agency (Embrapa) to introduce sustainable agriculture concepts in all steps of Research and Development (R and D). An essential part of the devised mission statement called for the impact assessment of all technology innovation resulting from R and D, under field conditions (ex-post). However, methods for impact assessment of technology innovations at the farmstead level appropriate for the institutional context were lacking. The environmental impact assessment (EIA) system (AMBITEC-AGRO) developed to attend that demand is composed by a set of weighing matrices constructed in an electronic spreadsheet. Impact indicators are evaluated in the field in an interview/survey, and weighed according to their spatial scale and importance toward effecting environmental impacts. The results of these weighing procedures are expressed graphically in the assessment spreadsheets. Finally, the indicator evaluations are composed into an Environmental Impact Index for the agricultural technology innovation

Measurement of astrophysical S-factors and electron screening potentials for d(d,n){sup 3}He reaction in ZrD{sub 2}, TiD{sub 2} and TaD{sub 0.5} targets in the ultralow energy region using plasma accelerator

Energy Technology Data Exchange (ETDEWEB)

Bystritsky, V.M., E-mail: bystvm@jinr.ru [Joint Institute for Nuclear Research, Dubna, Moscow Region (Russian Federation); Bystritskii, Vit.M. [Department of Physics and Astronomy, University of California, Irvine (United States); Dudkin, G.N. [National Scientific Research Tomsk Polytechnical University, Tomsk (Russian Federation); Filipowicz, M. [Faculty of Energy and Fuels, AGH, University of Science and Technology, Cracow (Poland); Gazi, S.; Huran, J. [Institute of Electrical Engineering, SAS, Bratislava (Slovakia); Kobzev, A.P. [Joint Institute for Nuclear Research, Dubna, Moscow Region (Russian Federation); Mesyats, G.A. [Lebedev Physical Institute of the Russian Academy of Sciences, Moscow (Russian Federation); Nechaev, B.A.; Padalko, V.N. [National Scientific Research Tomsk Polytechnical University, Tomsk (Russian Federation); Parzhitskii, S.S. [Joint Institute for Nuclear Research, Dubna, Moscow Region (Russian Federation); Pen' kov, F.M. [Institute of Nuclear Physics, NNC, Almaty (Kazakhstan); Philippov, A.V. [Joint Institute for Nuclear Research, Dubna, Moscow Region (Russian Federation); Kaminskii, V.L. [National Scientific Research Tomsk Polytechnical University, Tomsk (Russian Federation); Tuleushev, Yu.Zh. [Institute of Nuclear Physics, NNC, Almaty (Kazakhstan); Wozniak, J. [Faculty of Physics and Applied Computer Sciences, AGH, University of Science and Technology, Cracow (Poland)

2012-09-01

The present paper is devoted to the study of the electron screening effect influence on the rate of d(d,n){sup 3}He reaction in the ultralow deuteron collision energy range in the deuterated metals (ZrD{sub 2}, TiD{sub 2} and TaD{sub 0.5}). The ZrD{sub 2}, TiD{sub 2} and TaD0.5 targets were fabricated via magnetron sputtering of titanium, zirconium and tantalum in gas (deuterium) environment. The experiments have been carried out using the high-current pulsed Hall plasma accelerator (NSR TPU, Russia). The detection of neutrons with energy of 2.5 MeV from the dd reaction was done with plastic scintillation spectrometers. As a result of the experiments, the energy dependences of the astrophysical S-factor for the dd reaction in the deuteron collision energy range of 2-7 keV and the values of the electron screening potential U{sub e} of the interacting deuterons have been measured for the above targets: U{sub e}(ZrD{sub 2})=(205{+-}35) eV; U{sub e}(TiD{sub 2})=(125{+-}34) eV; U{sub e}(TaD{sub 0.5})=(313{+-}58) eV. Our results are compared with the other published experimental and calculated data.

Electronic and magnetic properties of 3d transition metal-doped strontium clusters: Prospective magnetic superatoms

International Nuclear Information System (INIS)

Chauhan, Vikas; Sen, Prasenjit

2013-01-01

Highlights: • Structural, electronic and magnetic properties of TM-Sr clusters are studied using DFT methods. • CrSr 9 and MnSr 10 have enhanced stability in the CrSr n and MnSrn series. • These two clusters behave as magnetic superatoms. • A qualitative understanding of the magnetic coupling between two superatom units is offered. • Reactivity of these superatoms to molecular oxygen also studied. - Abstract: Structural, electronic and magnetic properties of 3d transition metal doped strontium clusters are studied using first-principles electronic structure methods based on density functional theory. Clusters with enhanced kinetic and thermodynamic stability are identified by studying their hardness, second order energy difference and adiabatic spin excitation energy. CrSr 9 and MnSr 10 are found to have enhanced stability. They retain their structural identities in assemblies, and are classified as magnetic superatoms. A qualitative understanding of the magnetic coupling between two cluster units is arrived at. Reactivity of these superatoms with O 2 molecule is also studied. Prospects for using these magnetic superatoms in applications are discussed

Critical factors in SEM 3D stereo microscopy

DEFF Research Database (Denmark)

Marinello, F.; Bariano, P.; Savio, E.

2008-01-01

This work addresses dimensional measurements performed with the scanning electron microscope (SEM) using 3D reconstruction of surface topography through stereo-photogrammetry. The paper presents both theoretical and experimental investigations, on the effects of instrumental variables and measure......This work addresses dimensional measurements performed with the scanning electron microscope (SEM) using 3D reconstruction of surface topography through stereo-photogrammetry. The paper presents both theoretical and experimental investigations, on the effects of instrumental variables...... factors are recognized: the first one is related to the measurement operation and the instrument set-up; the second concerns the quality of scanned images and represents the major criticality in the application of SEMs for 3D characterizations....

A Framework for 3d Printing

DEFF Research Database (Denmark)

Pilkington, Alan; Frandsen, Thomas; Kapetaniou, Chrystalla

3D printing technologies and processes offer such a radical range of options for firms that we currently lack a structured way of recording possible impact and recommending actions for managers. The changes arising from 3d printing includes more than just new options for product design, but also...

Single impacts of keV fullerene ions on free standing graphene: Emission of ions and electrons from confined volume

Energy Technology Data Exchange (ETDEWEB)

Verkhoturov, Stanislav V.; Geng, Sheng; Schweikert, Emile A., E-mail: schweikert@chem.tamu.edu [Department of Chemistry, Texas A& M University, College Station, Texas 77843-3144 (United States); Czerwinski, Bartlomiej [Institute of Condensed Matter and Nanosciences–Bio and Soft Matter (IMCN/BSMA), Université Catholique de Louvain, 1 Croix du Sud, B-1348 Louvain-la-Neuve (Belgium); Applied Physics, Division of Materials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-971 87 Luleå (Sweden); Young, Amanda E. [Materials Characterization Facility, Texas A& M University, College Station, Texas 77843-3122 (United States); Delcorte, Arnaud [Institute of Condensed Matter and Nanosciences–Bio and Soft Matter (IMCN/BSMA), Université Catholique de Louvain, 1 Croix du Sud, B-1348 Louvain-la-Neuve (Belgium)

2015-10-28

We present the first data from individual C{sub 60} impacting one to four layer graphene at 25 and 50 keV. Negative secondary ions and electrons emitted in transmission were recorded separately from each impact. The yields for C{sub n}{sup −} clusters are above 10% for n ≤ 4, they oscillate with electron affinities and decrease exponentially with n. The result can be explained with the aid of MD simulation as a post-collision process where sufficient vibrational energy is accumulated around the rim of the impact hole for sputtering of carbon clusters. The ionization probability can be estimated by comparing experimental yields of C{sub n}{sup −} with those of C{sub n}{sup 0} from MD simulation, where it increases exponentially with n. The ionization probability can be approximated with ejecta from a thermally excited (3700 K) rim damped by cluster fragmentation and electron detachment. The experimental electron probability distributions are Poisson-like. On average, three electrons of thermal energies are emitted per impact. The thermal excitation model invoked for C{sub n}{sup −} emission can also explain the emission of electrons. The interaction of C{sub 60} with graphene is fundamentally different from impacts on 3D targets. A key characteristic is the high degree of ionization of the ejecta.

Impact of Particle Size of Ceramic Granule Blends on Mechanical Strength and Porosity of 3D Printed Scaffolds

Directory of Open Access Journals (Sweden)

Sebastian Spath

2015-07-01

Full Text Available 3D printing is a promising method for the fabrication of scaffolds in the field of bone tissue engineering. To date, the mechanical strength of 3D printed ceramic scaffolds is not sufficient for a variety of applications in the reconstructive surgery. Mechanical strength is directly in relation with the porosity of the 3D printed scaffolds. The porosity is directly influenced by particle size and particle-size distribution of the raw material. To investigate this impact, a hydroxyapatite granule blend with a wide particle size distribution was fractioned by sieving. The specific fractions and bimodal mixtures of the sieved granule blend were used to 3D print specimens. It has been shown that an optimized arrangement of fractions with large and small particles can provide 3D printed specimens with good mechanical strength due to a higher packing density. An increase of mechanical strength can possibly expand the application area of 3D printed hydroxyapatite scaffolds.

Calculation of the electronic and magnetic structures of 3d impurities in the Hcp Fe matrix

International Nuclear Information System (INIS)

Franca, Fernando

1995-01-01

In this work we investigate the local magnetic properties and the electronic structure of HCP Fe, as well introducing transition metals atoms 3d (Cs, Ti, Cr, Mn, Co, Ni, Cu, Zn) in HCP iron matrix. We employed the discrete variational method (DVM), which is an orbital molecular method which incorporate the Hartree-Fock-Slater theory and the linear combination of atomic orbitals (LCAO), in the self-consistent charge approximation and the local density approximation of Von Barth and Hedin to the exchange-correlation potential. We used the embedded cluster model to investigate the electronic structure and the local magnetic properties for the central atom of a cluster of 27 atoms immersed in the microcrystal representing the HCP Fe. (author)

PEC Reliability in 3D E-beam DOE Nanopatterning

Czech Academy of Sciences Publication Activity Database

Krátký, Stanislav; Urbánek, Michal; Kolařík, Vladimír

2015-01-01

Roč. 21, S4 (2015), s. 230-235 ISSN 1431-9276 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : proximity effect correction * diffractive optical elements Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.730, year: 2015

Electronic transitions and bonding properties in a series of five-coordinate "16-electron" complexes [Mn(CO)3(L2)]- (L2 = chelating redox-active .pi.-donor ligand)

Czech Academy of Sciences Publication Activity Database

Hartl, F.; Rosa, P.; Ricard, L.; Le Floch, P.; Záliš, Stanislav

2007-01-01

Roč. 251, 3-4 (2007), s. 557-576 ISSN 0010-8545 R&D Projects: GA MŠk 1P05OC068; GA AV ČR 1ET400400413 Institutional research plan: CEZ:AV0Z40400503 Keywords : manganese carbonyl * .pi.-donor ligand * electronic delocalization * Five-coordinate complex Subject RIV: CG - Electrochemistry Impact factor: 8.568, year: 2007

Electron impact phenomena and the properties of gaseous ions

CERN Document Server

Field, F H; Massey, H S W; Brueckner, Keith A

1970-01-01

Electron Impact Phenomena and the Properties of Gaseous Ions, Revised Edition deals with data pertaining to electron impact and to molecular gaseous ionic phenomena. This book discusses electron impact phenomena in gases at low pressure that involve low-energy electrons, which result in ion formation. The text also describes the use of mass spectrometers in electron impact studies and the degree of accuracy obtained when measuring electron impact energies. This book also reviews relatively low speed electrons and the transitions that result in the ionization of the atomic system. This text the

1,3Do and 1,3Pe states of two electron atoms under Debye plasma screening

International Nuclear Information System (INIS)

Saha, Jayanta K.; Bhattacharyya, S.; Mukherjee, T.K.; Mukherjee, P.K.

2010-01-01

Extensive non-relativistic variational calculations for estimating the energy values of 2pnd( 1,3 D o ) states [n=3-6] of two electron atoms (He, Li + ,Be 2+ ) and 2pnp( 1 P e )[n=3-8] and 2pnp( 3 P e ) states [n=2-7] of Be 2+ under weakly coupled plasma screening have been performed using explicitly correlated Hylleraas type basis. The modified energy eigenvalues of 1,3 P e states arising from two p electrons of Be 2+ ion and 1,3 D o states due to 2pnd configuration of Li + and Be 2+ ion in the Debye plasma environment are being reported for the first time. The effect of plasma has been incorporated through the Debye screening model. The system tends towards gradual instability and the number of bound states reduces with increasing plasma coupling strength. The wavelengths for 2pn ' p( 1 P e )[n ' =3-8]→2pnd( 1 D o )[n=3-6] and 2pn ' p( 3 P e )[n ' =2-8]→2pnd( 3 D o )[n=3-6] transitions in plasma embedded two electron atoms have also been reported.

2D Dirac electrons in 3D materials

NARCIS (Netherlands)

Ramankutty, S.V.

2018-01-01

Quantum materials pack the spooky properties of quantum mechanics into real-life materials you can make, pick up with tweezers and study in the lab. Those of interest to us show special electronic properties of great fundamental interest and have applications potential for future computer and

Realizing Large-Scale, Electronic-Grade Two-Dimensional Semiconductors.

Science.gov (United States)

Lin, Yu-Chuan; Jariwala, Bhakti; Bersch, Brian M; Xu, Ke; Nie, Yifan; Wang, Baoming; Eichfeld, Sarah M; Zhang, Xiaotian; Choudhury, Tanushree H; Pan, Yi; Addou, Rafik; Smyth, Christopher M; Li, Jun; Zhang, Kehao; Haque, M Aman; Fölsch, Stefan; Feenstra, Randall M; Wallace, Robert M; Cho, Kyeongjae; Fullerton-Shirey, Susan K; Redwing, Joan M; Robinson, Joshua A

2018-02-27

Atomically thin transition metal dichalcogenides (TMDs) are of interest for next-generation electronics and optoelectronics. Here, we demonstrate device-ready synthetic tungsten diselenide (WSe 2 ) via metal-organic chemical vapor deposition and provide key insights into the phenomena that control the properties of large-area, epitaxial TMDs. When epitaxy is achieved, the sapphire surface reconstructs, leading to strong 2D/3D (i.e., TMD/substrate) interactions that impact carrier transport. Furthermore, we demonstrate that substrate step edges are a major source of carrier doping and scattering. Even with 2D/3D coupling, transistors utilizing transfer-free epitaxial WSe 2 /sapphire exhibit ambipolar behavior with excellent on/off ratios (∼10 7 ), high current density (1-10 μA·μm -1 ), and good field-effect transistor mobility (∼30 cm 2 ·V -1 ·s -1 ) at room temperature. This work establishes that realization of electronic-grade epitaxial TMDs must consider the impact of the TMD precursors, substrate, and the 2D/3D interface as leading factors in electronic performance.

D-Zero muon readout electronics design

International Nuclear Information System (INIS)

Baldin, B.; Hansen, S.; Los, S.; Matveev, M.; Vaniev, V.

1996-11-01

The readout electronics designed for the D null Muon Upgrade are described. These electronics serve three detector subsystems and one trigger system. The front-ends and readout hardware are synchronized by means of timing signals broadcast from the D null Trigger Framework. The front-end electronics have continuously running digitizers and two levels of buffering resulting in nearly deadtimeless operation. The raw data is corrected and formatted by 16- bit fixed point DSP processors. These processors also perform control of the data buffering. The data transfer from the front-end electronics located on the detector platform is performed by serial links running at 160 Mbit/s. The design and test results of the subsystem readout electronics and system interface are discussed

Ripple-modulated electronic structure of a 3D topological insulator.

Science.gov (United States)

Okada, Yoshinori; Zhou, Wenwen; Walkup, D; Dhital, Chetan; Wilson, Stephen D; Madhavan, V

2012-01-01

Three-dimensional topological insulators host linearly dispersing states with unique properties and a strong potential for applications. An important ingredient in realizing some of the more exotic states in topological insulators is the ability to manipulate local electronic properties. Direct analogy to the Dirac material graphene suggests that a possible avenue for controlling local properties is via a controlled structural deformation such as the formation of ripples. However, the influence of such ripples on topological insulators is yet to be explored. Here we use scanning tunnelling microscopy to determine the effects of one-dimensional buckling on the electronic properties of Bi(2)Te(3.) By tracking spatial variations of the interference patterns generated by the Dirac electrons we show that buckling imposes a periodic potential, which locally modulates the surface-state dispersion. This suggests that forming one- and two-dimensional ripples is a viable method for creating nanoscale potential landscapes that can be used to control the properties of Dirac electrons in topological insulators.

Adsorption on metal oxides Studies with the metastable impact electron spectroscopy

CERN Document Server

Krischok, S; Kempter, V

2002-01-01

An overview is given on the application of metastable impact electron spectroscopy, in combination with UPS, to the study of clean magnesia and titania surfaces and their interaction with metal atoms and small molecules. The mechanisms for metal adsorption on reducible (titania) and non-reducible (magnesia) substrates are different: while on titania the metal atom often bonds by electron transfer to Ti3d states, it is hybridization of the adsorbate and anion wavefunctions which accounts for the bonding on MgO. In the case of H sub 2 O, molecular adsorption takes place both on MgO and TiO sub 2; on the other hand, water-alkali coadsorption leads to hydroxide formation. In the case of CO sub 2 , chemisorption takes place in form of carbonate (CO sub 3) species. These originate from the CO sub 2 interaction with O sup 2 sup - surface anions. While for CaO chemisorption takes place at regular oxygen sites, for MgO this occurs at low-coordinated oxygen ions only; for TiO sub 2 chemisorption requires alkali coadsor...

Adsorption on metal oxides: Studies with the metastable impact electron spectroscopy

International Nuclear Information System (INIS)

Krischok, S.; Hoefft, O.; Kempter, V.

2002-01-01

An overview is given on the application of metastable impact electron spectroscopy, in combination with UPS, to the study of clean magnesia and titania surfaces and their interaction with metal atoms and small molecules. The mechanisms for metal adsorption on reducible (titania) and non-reducible (magnesia) substrates are different: while on titania the metal atom often bonds by electron transfer to Ti3d states, it is hybridization of the adsorbate and anion wavefunctions which accounts for the bonding on MgO. In the case of H 2 O, molecular adsorption takes place both on MgO and TiO 2 ; on the other hand, water-alkali coadsorption leads to hydroxide formation. In the case of CO 2 , chemisorption takes place in form of carbonate (CO 3 ) species. These originate from the CO 2 interaction with O 2- surface anions. While for CaO chemisorption takes place at regular oxygen sites, for MgO this occurs at low-coordinated oxygen ions only; for TiO 2 chemisorption requires alkali coadsorption

3D printing scanning electron microscopy sample holders: A quick and cost effective alternative for custom holder fabrication.

Directory of Open Access Journals (Sweden)

Gabriel N Meloni

Full Text Available A simple and cost effective alternative for fabricating custom Scanning Electron Microscope (SEM sample holders using 3D printers and conductive polylactic acid filament is presented. The flexibility of the 3D printing process allowed for the fabrication of sample holders with specific features that enable the high-resolution imaging of nanoelectrodes and nanopipettes. The precise value of the inner semi cone angle of the nanopipettes taper was extracted from the acquired images and used for calculating their radius using electrochemical methods. Because of the low electrical resistivity presented by the 3D printed holder, the imaging of non-conductive nanomaterials, such as alumina powder, was found to be possible. The fabrication time for each sample holder was under 30 minutes and the average cost was less than $0.50 per piece. Despite being quick and economical to fabricate, the sample holders were found to be sufficiently resistant, allowing for multiple uses of the same holder.

Stability and electronic structure studies of LaAlO3/SrTiO3 (110) heterostructures

International Nuclear Information System (INIS)

Du Yan-Ling; Wang Chun-Lei; Li Ji-Chao; Xu Pan-Pan; Zhang Xin-Hua; Liu Jian; Su Wen-Bin; Mei Liang-Mo

2014-01-01

The first-principles calculations are employed to investigate the stability, magnetic, and electrical properties of the oxide heterostructure of LaAlO 3 /SrTiO 3 (110). By comparing their interface energies, it is obtained that the buckled interface is more stable than the abrupt interface. This result is consistent with experimental observation. At the interface of LaAlO 3 /SrTiO 3 (110) heterostructure, the Ti—O octahedron distortions cause the Ti t 2g orbitals to split into the two-fold degenerate d xz /d yz and nondegenerate d xy orbitals. The former has higher energy than the latter. The partly filled two-fold degenerate t 2g orbitals are the origin of two-dimensional electron gas, which is confined at the interface. Lattice mismatch between LaAlO 3 and SrTiO 3 leads to ferroelectric-like lattice distortions at the interface, and this is the origin of spin-splitting of Ti 3d electrons. Hence the magnetism appears at the interface of LaAlO 3 /SrTiO 3 (110). (condensed matter: electronic structure, electrical, magnetic, and optical properties)

KPG Index versus OPG Measurements: A Comparison between 3D and 2D Methods in Predicting Treatment Duration and Difficulty Level for Patients with Impacted Maxillary Canines

Directory of Open Access Journals (Sweden)

Domenico Dalessandri

2014-01-01

Full Text Available Aim. The aim of this study was to test the agreement between orthopantomography (OPG based 2D measurements and the KPG index, a new index based on 3D Cone Beam Computed Tomography (CBCT images, in predicting orthodontic treatment duration and difficulty level of impacted maxillary canines. Materials and Methods. OPG and CBCT images of 105 impacted canines were independently scored by three orthodontists at t0 and after 1 month (t1, using the KPG index and the following 2D methods: distance from cusp tip and occlusal plane, cusp tip position in relation to the lateral incisor, and canine inclination. Pearson’s coefficients were used to evaluate the degree of agreement and the χ2 with Yates correction test was used to assess the independence between them. Results. Inter- and intrarater reliability were higher with KPG compared to 2D methods. Pearson’s coefficients showed a statistically significant association between all the indexes, while the χ2 with Yates correction test resulted in a statistically significant rejection of independency only for one 2D index. Conclusions. 2D indexes for predicting impacted maxillary canines treatment duration and difficulty sometimes are discordant; a 3D index like the KPG index could be useful in solving these conflicts.

On Secondary Electron Emission from Solid H2 and D2

DEFF Research Database (Denmark)

Schou, Jørgen; Sørensen, H.

1978-01-01

The emission of secondary electrons from solid hydrogen (H2 , D2, T2) is often considered to be of importance for the interaction between a fusion plasma and pellets of solid hydrogens. A set-up was therefore built for studies of interactions between energetic particles and solid hydrogens. Studies...... of secondary electron emission (SEE) from solid H2 and D2 were made for incidence of electrons up to 3 keV and for incidence of ions of hydrogen, deuterium, and helium up to 10 keV. The measurements were made for normal incidence, and in some cases also for oblique incidence. The SEE coefficients for solid H2...... is always 0.65-0.70 times that for solid D2. This difference is attributed to different losses to vibrational states in H2 and D2 for the low energy electrons. Measurements were also made on solid para-H2 with both electrons and hydrogen ions. There was no difference from the results for normal H2, which...

Comparative evaluation of HD 2D/3D laparoscopic monitors and benchmarking to a theoretically ideal 3D pseudodisplay: even well-experienced laparoscopists perform better with 3D.

Science.gov (United States)

Wilhelm, D; Reiser, S; Kohn, N; Witte, M; Leiner, U; Mühlbach, L; Ruschin, D; Reiner, W; Feussner, H

2014-08-01

Though theoretically superior to standard 2D visualization, 3D video systems have not yet achieved a breakthrough in laparoscopy. The latest 3D monitors, including autostereoscopic displays and high-definition (HD) resolution, are designed to overcome the existing limitations. We performed a randomized study on 48 individuals with different experience levels in laparoscopy. Three different 3D displays (glasses-based 3D monitor, autostereoscopic display, and a mirror-based theoretically ideal 3D display) were compared to a 2D HD display by assessing multiple performance and mental workload parameters and rating the subjects during a laparoscopic suturing task. Electromagnetic tracking provided information on the instruments' pathlength, movement velocity, and economy. The usability, the perception of visual discomfort, and the quality of image transmission of each monitor were subjectively rated. Almost all performance parameters were superior with the conventional glasses-based 3D display compared to the 2D display and the autostereoscopic display, but were often significantly exceeded by the mirror-based 3D display. Subjects performed a task faster and with greater precision when visualization was achieved with the 3D and the mirror-based display. Instrument pathlength was shortened by improved depth perception. Workload parameters (NASA TLX) did not show significant differences. Test persons complained of impaired vision while using the autostereoscopic monitor. The 3D and 2D displays were rated user-friendly and applicable in daily work. Experienced and inexperienced laparoscopists profited equally from using a 3D display, with an improvement in task performance about 20%. Novel 3D displays improve laparoscopic interventions as a result of faster performance and higher precision without causing a higher mental workload. Therefore, they have the potential to significantly impact the further development of minimally invasive surgery. However, as shown by the

Highly-stretchable 3D-architected Mechanical Metamaterials

Science.gov (United States)

Jiang, Yanhui; Wang, Qiming

2016-09-01

Soft materials featuring both 3D free-form architectures and high stretchability are highly desirable for a number of engineering applications ranging from cushion modulators, soft robots to stretchable electronics; however, both the manufacturing and fundamental mechanics are largely elusive. Here, we overcome the manufacturing difficulties and report a class of mechanical metamaterials that not only features 3D free-form lattice architectures but also poses ultrahigh reversible stretchability (strain > 414%), 4 times higher than that of the existing counterparts with the similar complexity of 3D architectures. The microarchitected metamaterials, made of highly stretchable elastomers, are realized through an additive manufacturing technique, projection microstereolithography, and its postprocessing. With the fabricated metamaterials, we reveal their exotic mechanical behaviors: Under large-strain tension, their moduli follow a linear scaling relationship with their densities regardless of architecture types, in sharp contrast to the architecture-dependent modulus power-law of the existing engineering materials; under large-strain compression, they present tunable negative-stiffness that enables ultrahigh energy absorption efficiencies. To harness their extraordinary stretchability and microstructures, we demonstrate that the metamaterials open a number of application avenues in lightweight and flexible structure connectors, ultraefficient dampers, 3D meshed rehabilitation structures and stretchable electronics with designed 3D anisotropic conductivity.

Calibrating MMS Electron Drift Instrument (EDI) Ambient Electron Flux Measurements and Characterizing 3D Electric Field Signatures of Magnetic Reconnection

Science.gov (United States)

Shuster, J. R.; Torbert, R. B.; Vaith, H.; Argall, M. R.; Li, G.; Chen, L. J.; Ergun, R. E.; Lindqvist, P. A.; Marklund, G. T.; Khotyaintsev, Y. V.; Russell, C. T.; Magnes, W.; Le Contel, O.; Pollock, C. J.; Giles, B. L.

2015-12-01

The electron drift instruments (EDIs) onboard each MMS spacecraft are designed with large geometric factors (~0.01cm2 str) to facilitate detection of weak (~100 nA) electron beams fired and received by the two gun-detector units (GDUs) when EDI is in its "electric field mode" to determine the local electric and magnetic fields. A consequence of the large geometric factor is that "ambient mode" electron flux measurements (500 eV electrons having 0°, 90°, or 180° pitch angle) can vary depending on the orientation of the EDI instrument with respect to the magnetic field, a nonphysical effect that requires a correction. Here, we present determinations of the θ- and ø-dependent correction factors for the eight EDI GDUs, where θ (ø) is the polar (azimuthal) angle between the GDU symmetry axis and the local magnetic field direction, and compare the corrected fluxes with those measured by the fast plasma instrument (FPI). Using these corrected, high time resolution (~1,000 samples per second) ambient electron fluxes, combined with the unprecedentedly high resolution 3D electric field measurements taken by the spin-plane and axial double probes (SDP and ADP), we are equipped to accurately detect electron-scale current layers and electric field waves associated with the non-Maxwellian (anisotropic and agyrotropic) particle distribution functions predicted to exist in the reconnection diffusion region. We compare initial observations of the diffusion region with distributions and wave analysis from PIC simulations of asymmetric reconnection applicable for modeling reconnection at the Earth's magnetopause, where MMS will begin Science Phase 1 as of September 1, 2015.

Probing collective oscillation of d -orbital electrons at the nanoscale

Energy Technology Data Exchange (ETDEWEB)

Dhall, Rohan [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA; Vigil-Fowler, Derek [National Renewable Energy Laboratory, Golden, Colorado 80401, USA; Houston Dycus, J. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA; Kirste, Ronny [Adroit Materials, Inc., Cary, North Carolina 27518, USA; Mita, Seiji [Adroit Materials, Inc., Cary, North Carolina 27518, USA; Sitar, Zlatko [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA; Collazo, Ramon [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA; LeBeau, James M. [Adroit Materials, Inc., Cary, North Carolina 27518, USA

2018-02-05

Here, we demonstrate that high energy electrons can be used to explore the collective oscillation of s, p, and d orbital electrons at the nanometer length scale. Using epitaxial AlGaN/AlN quantum wells as a test system, we observe the emergence of additional features in the loss spectrum with the increasing Ga content. A comparison of the observed spectra with ab-initio theory reveals that the origin of these spectral features lies in excitations of 3d-electrons contributed by Ga. We find that these modes differ in energy from the valence electron plasmons in Al1-xGaxN due to the different polarizabilities of the d electrons. Finally, we study the dependence of observed spectral features on the Ga content, lending insights into the origin of these spectral features, and their coupling with electron-hole excitations.

Numerical simulation of runaway electrons: 3-D effects on synchrotron radiation and impurity-based runaway current dissipation

Science.gov (United States)

del-Castillo-Negrete, D.; Carbajal, L.; Spong, D.; Izzo, V.

2018-05-01

Numerical simulations of runaway electrons (REs) with a particular emphasis on orbit dependent effects in 3-D magnetic fields are presented. The simulations were performed using the recently developed Kinetic Orbit Runaway electron Code (KORC) that computes the full-orbit relativistic dynamics in prescribed electric and magnetic fields including radiation damping and collisions. The two main problems of interest are synchrotron radiation and impurity-based RE dissipation. Synchrotron radiation is studied in axisymmetric fields and in 3-D magnetic configurations exhibiting magnetic islands and stochasticity. For passing particles in axisymmetric fields, neglecting orbit effects might underestimate or overestimate the total radiation power depending on the direction of the radial shift of the drift orbits. For trapped particles, the spatial distribution of synchrotron radiation exhibits localized "hot" spots at the tips of the banana orbits. In general, the radiation power per particle for trapped particles is higher than the power emitted by passing particles. The spatial distribution of synchrotron radiation in stochastic magnetic fields, obtained using the MHD code NIMROD, is strongly influenced by the presence of magnetic islands. 3-D magnetic fields also introduce a toroidal dependence on the synchrotron spectra, and neglecting orbit effects underestimates the total radiation power. In the presence of magnetic islands, the radiation damping of trapped particles is larger than the radiation damping of passing particles. Results modeling synchrotron emission by RE in DIII-D quiescent plasmas are also presented. The computation uses EFIT reconstructed magnetic fields and RE energy distributions fitted to the experimental measurements. Qualitative agreement is observed between the numerical simulations and the experiments for simplified RE pitch angle distributions. However, it is noted that to achieve quantitative agreement, it is necessary to use pitch angle

Voltammetric Studies on Vitamins D2 and D3 in Organic Solvents

International Nuclear Information System (INIS)

Chan, Ya Yun; Yue, Yanni; Webster, Richard D.

2014-01-01

Highlights: • Vitamins D 2 and D 3 undergo a chemically irreversible oxidation process. • The electrochemical oxidation occurs via one-electron on short (CV) time-scales. • On long time scales (electrolysis) the oxidation occurs via two-electrons. • Chemical oxidation was performed using two molar equivalents of NO + . • Oxidation occurs at the triene moiety. - Abstract: The electrochemical behavior of vitamins D 2 and D 3 were examined by performing cyclic voltammetry (CV), rotating disk electrode voltammetry, controlled potential electrolysis and chemical oxidation in aprotic organic solvents. Both vitamins were electrochemically oxidized in dichloromethane and acetonitrile (E p ox ∼ +0.8 vs. (Fc/Fc + )/V, where E p ox is the anodic peak potential and Fc = ferrocene) via a one-electron chemically irreversible process on the short voltammetric time scale (≤ seconds). Varying the scan rate (0.1 V s −1 to 20 V s −1 ) and temperature (233 K to 293 K) did not strongly affect the voltammetric response recorded on platinum and glassy carbon electrode surfaces with the oxidation process remaining chemically irreversible over the range of scan rates and temperatures tested, indicating that the initially formed cation radical was not long-lived. Repetitive CV experiments indicated that the oxidized product partially adsorbed onto the electrode surface, resulting in diminishing peak currents with multiple scans. Bulk controlled potential electrolysis of the vitamin D compounds performed by alternating several cycles of oxidative electrolysis and reductive pulsed stripping proved to be effective in stripping the adsorbed species off the electrode surfaces. Longer time scale bulk electrolysis experiments led to the detection of a new oxidation peak appearing at less positive potentials as the electrolysis progressed, suggesting that the compounds underwent oxidation on long time scales (minutes to hours) via a two electron process. The vitamins were most

A computational study of magnetic exchange interactions of 3d and 4f electrons in Ti-Ce co-doped AlN

Energy Technology Data Exchange (ETDEWEB)

Majid, Abdul, E-mail: abdulmajid40@yahoo.com [Department of Physics, University of Gujrat, Gujrat (Pakistan); Department of Adaptive Machine Systems, Osaka University, Osaka (Japan); Azmat, Mian [Department of Physics, University of Gujrat, Gujrat (Pakistan); Rana, Usman Ali; Khan, Salah Ud-Din [Sustainable Energy Technologies Center, College of Engineering, King Saud University, PO-Box 800, Riyadh 11421 (Saudi Arabia); Alzahrani, Eman [Department of Chemistry, Faculty of Science, Taif University, 888 Taif (Saudi Arabia)

2016-08-15

To investigate the nature of 3d-4f exchange interactions in III-Nitride semiconductors, Ti-Ce co-doped AlN were studied using first principles calculations. The calculations were performed using supercell approach with varying dopant concentration and different inter-dopant separation. The configuration with dopant located as nearest neighbor distance and diluted concentration of 3.125% was found most stable. The results exhibited prominent evidence of 3d-4f-5d strong hybridization suggesting 3d-4f direct exchange interactions which may play valuable role to exploit the system as high Curie temperature ferromagnetic semiconductors for use in spintronics. Moreover, metal to metal charge transfer was also observed in the materials which may be exploited for their use in electrochemical applications. The 4f-5d and 3d-5d hybridizations were observed that predicts excellent luminescence phenomena in the materials. The presence of impurity related deep intermediate bands suggest applications of the materials in opto-electronic and spintronics devices. - Highlights: • Double exchange interaction in Ti:AlN. • Impurity induced narrowing of band gap. • Superexchange interaction in Ce:AlN. • 3d-4f exchange interaction between Ti-3d and Ce-4f states. • High Curie temperature n-type ferromagnetic semiconductors.

A computational study of magnetic exchange interactions of 3d and 4f electrons in Ti-Ce co-doped AlN

International Nuclear Information System (INIS)

Majid, Abdul; Azmat, Mian; Rana, Usman Ali; Khan, Salah Ud-Din; Alzahrani, Eman

2016-01-01

To investigate the nature of 3d-4f exchange interactions in III-Nitride semiconductors, Ti-Ce co-doped AlN were studied using first principles calculations. The calculations were performed using supercell approach with varying dopant concentration and different inter-dopant separation. The configuration with dopant located as nearest neighbor distance and diluted concentration of 3.125% was found most stable. The results exhibited prominent evidence of 3d-4f-5d strong hybridization suggesting 3d-4f direct exchange interactions which may play valuable role to exploit the system as high Curie temperature ferromagnetic semiconductors for use in spintronics. Moreover, metal to metal charge transfer was also observed in the materials which may be exploited for their use in electrochemical applications. The 4f-5d and 3d-5d hybridizations were observed that predicts excellent luminescence phenomena in the materials. The presence of impurity related deep intermediate bands suggest applications of the materials in opto-electronic and spintronics devices. - Highlights: • Double exchange interaction in Ti:AlN. • Impurity induced narrowing of band gap. • Superexchange interaction in Ce:AlN. • 3d-4f exchange interaction between Ti-3d and Ce-4f states. • High Curie temperature n-type ferromagnetic semiconductors.

3D structure of eukaryotic flagella in a quiescent state revealed by cryo-electron tomography

Science.gov (United States)

Nicastro, Daniela; McIntosh, J. Richard; Baumeister, Wolfgang

2005-01-01

We have used cryo-electron tomography to investigate the 3D structure and macromolecular organization of intact, frozen-hydrated sea urchin sperm flagella in a quiescent state. The tomographic reconstructions provide information at a resolution better than 6 nm about the in situ arrangements of macromolecules that are key for flagellar motility. We have visualized the heptameric rings of the motor domains in the outer dynein arm complex and determined that they lie parallel to the plane that contains the axes of neighboring flagellar microtubules. Both the material associated with the central pair of microtubules and the radial spokes display a plane of symmetry that helps to explain the planar beat pattern of these flagella. Cryo-electron tomography has proven to be a powerful technique for helping us understand the relationships between flagellar structure and function and the design of macromolecular machines in situ. PMID:16246999

3D Printing Multi-Functionality: Embedded RF Antennas and Components

Science.gov (United States)

Shemelya, C. M.; Zemba, M.; Liang, M.; Espalin, D.; Kief, C.; Xin, H.; Wicker, R. B.; MacDonald, E. W.

2015-01-01

Significant research and press has recently focused on the fabrication freedom of Additive Manufacturing (AM) to create both conceptual models and final end-use products. This flexibility allows design modifications to be immediately reflected in 3D printed structures, creating new paradigms within the manufacturing process. 3D printed products will inevitably be fabricated locally, with unit-level customization, optimized to unique mission requirements. However, for the technology to be universally adopted, the processes must be enhanced to incorporate additional technologies; such as electronics, actuation, and electromagnetics. Recently, a novel 3D printing platform, Multi3D manufacturing, was funded by the presidential initiative for revitalizing manufacturing in the USA using 3D printing (America Makes - also known as the National Additive Manufacturing Innovation Institute). The Multi3D system specifically targets 3D printed electronics in arbitrary form; and building upon the potential of this system, this paper describes RF antennas and components fabricated through the integration of material extrusion 3D printing with embedded wire, mesh, and RF elements.

Refinements in the vibration frequencies of H3+ and D3+

International Nuclear Information System (INIS)

Carney, G.D.

1980-01-01

Refinements in vibration intervals of the order of 1 per cent are reported for H 3 + and D 3 + . These improved intervals result from the addition of polarization terms to the electronic wavefunction previously obtained with a complete configuration-interaction treatment of electron correlation using a 21 floating gaussian lobe basis. Twelve additional floating gaussian lobe orbitals were used to construct 78 additional configuration-interaction functions. Positions and exponents of these additional floating gaussian lobe orbitals were carefully chosen to allow for polarization of the correlated wavefunctions. Calculated vibrational state-averaged and observed geometries for H 3 + agree to within 0.01 A; refined fundamental frequencies are νsub(A) = 3220.48 and νsub(E) = 2545.99 cm -1 for H 3 + , and νsub(A) = 2332.94 and νsub(E) = 1848.12 cm -1 for D 3 + . Einstein coefficients for spontaneous emission of radiation from infrared active states of H 3 + and D 3 + are reported, and an alternative to the Carney-Porter method of vibration analysis is used to confirm the accuracy of their method for axial molecules such as H 3 + . (author)

Threshold electron impact ionization of molecules (CF4, CHF3, CH4, C3H8) and clusters (Ar, Ne, H2, D2), dissociative electron attachment to hydrogen and surface induced reactions of fullerenes (Cn, n=50-60)

International Nuclear Information System (INIS)

Fiegele, T.

2001-02-01

: a) in the present study the appearance energy of the dimer ion is always equal or lower than the appearance energy of the trimer ion and b) the present appearance energies of larger clusters are shifted to higher values as compared to the photoionization data where available (e.g. in the case of Ar). Taking into account the present accuracy we are able to demonstrate that for rare gas clusters the electron impact ionization process proceeds in a different way than photoionization. Moreover, as there is no simple way to mass select neutral clusters before ionization also the amount of cluster ions that are produced from larger clusters by evaporation can influence the appearance energies. We have studied this phenomenon by changing the stagnation gas temperature (and therefore the cluster size distribution). We clearly observe a dependence that supports this idea. The evaluation of appearance energies was also tested by studying parent and fragment ions of methane and propane. Following this, the appearance energies of the greenhouse gases carbon tetrafluoride and trifluoromethane were measured. Both gases are used in the semiconductor industry and especially for the CHF3 only a few and limited data sets were available up to now. The present measurements improve and complete the tabulated values. The present set-up allows also the study of high resolution electron attachment reactions. This technique was applied to dissociative electron attachment to hydrogen. This process is an important source for large concentrations of H- in low temperature plasmas and the detailed knowledge of the formation is very important for modeling of such plasmas in thermonuclear fusion devices. It was possible to solve discrepancies between earlier experiments and theoretical results concerning the cross section of the electron attachment in the energy range of about 4 eV. With additional results from a trochoidal electron monochromator a detailed study on the influence of rotational

On the Emission of Electrons from Solid H_2 and D_2 by Bombardment with 1-3 keV Electrons up to Very Large Angles of Incidence

DEFF Research Database (Denmark)

Schou, Jørgen; Sørensen, H.

1982-01-01

at the largest angles. The results agree well with the existing qualitative tendencies described in the literature. The variation with the angle of incidence shows a fair agreement with an estimate based on data for the angular distribution of electrons ejected from ionized hydrogen molecules. In addition......Electron emission, i.e. electron reflection (ER) and secondary electron emission (SEE), was studied for solid H2 and D2 for oblique incidence of 1-3 keV electrons up to an angle of incidence θ of 83°. The ER coefficient η was small at low angles, and rose rapidly with increasing θ above 60......, an ionization cascade treatment leads to an expression for the behavior of the yield of those secondary electrons that are generated directly by the primaries. The agreement with experimental data is good...

Hyperfine structure in 5s4d [sup 3]D-5snf transitions of [sup 87]Sr

Energy Technology Data Exchange (ETDEWEB)

Bushaw, B.A. (Pacific Northwest Lab., Richland, WA (United States)); Kluge, H.J. (Mainz Univ. (Germany). Inst. fuer Physik); Lantzsch, J. (Mainz Univ. (Germany). Inst. fuer Physik); Schwalbach, R. (Mainz Univ. (Germany). Inst. fuer Physik); Stenner, J. (Mainz Univ. (Germany). Inst. fuer Physik); Stevens, H. (Mainz Univ. (Germany). Inst. fuer Physik); Wendt, K. (Mainz Univ. (Germany). Inst. fuer Physik); Zimmer, K. (Mainz Univ. (Germany). Inst. fuer Physik)

1993-12-01

The hyperfine spectra of the 5s4d[sup 3]D[sub 1]-5s20f, 5s4d[sup 3]D[sub 2]-5s23f, and 5s4d[sup 3]D[sub 3]-5s32f transitions of [sup 87]Sr (I=9/2) have been measured by collinear fast beam laser spectroscopy. The structure in the upper configurations is highly perturbed by fine structure splitting that is of comparable size to the hyperfine interaction energy. These perturbations can be adequately treated with conventional matrix diagonalization methods, using the 5s-electron magnetic dipole interaction term a[sub 5s] and the unperturbed fine structure splittings as input parameters. Additionally, hyperfine constants for the lower 5s4d[sup 3]D configurations, including the A- and B-factors and a separation of the individual s- and d-electron contributions to these factors, are derived. (orig.)

Electron-impact dissociative ionization of CClF3 and CCl3F

International Nuclear Information System (INIS)

Martinez, Roberto; Sierra, Borja; Basterretxea, Francisco J.; Sanchez Rayo, Maria N.; Castano, Fernando

2006-01-01

A crossed-beam experiment of well characterized kinetic energy (KE) electrons and supersonic halomethanes CCl 3 F and CClF 3 in Ar carrier has been carried out in order to quantify the kinetic energy distributions (KEDs), the appearance energies (AEs) and the channels involved in the production of nascent ions. The ion KEDs were derived from the band profiles of the time-of-flight mass spectrum and the total KEDs computed using conservation laws. Heavier ions are created with KED peaked at thermal energies in contrast with low mass atoms or other fragments, where the distribution is broader and the maximum is at much higher energies. A discussion of the dissociative ionization pathways derived from the appearance energies, total average KEDs, thermodynamic enthalpies and computed electron dissociation energies is reported. The role of the vibrational and rotational energies into the dissociative processes is also discussed

3-D Bidirectional Propagation Algorithm Based on Fourier Series

Czech Academy of Sciences Publication Activity Database

Čtyroký, Jiří

2012-01-01

Roč. 30, č. 23 (2012), s. 3699-30708 ISSN 0733-8724 R&D Projects: GA ČR(CZ) GAP205/10/0046; GA MŠk OC09061 Institutional support: RVO:67985882 Keywords : optics * gratings Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.555, year: 2012

Correlative two-photon and serial block face scanning electron microscopy in neuronal tissue using 3D near-infrared branding maps.

Science.gov (United States)

Lees, Robert M; Peddie, Christopher J; Collinson, Lucy M; Ashby, Michael C; Verkade, Paul

2017-01-01

Linking cellular structure and function has always been a key goal of microscopy, but obtaining high resolution spatial and temporal information from the same specimen is a fundamental challenge. Two-photon (2P) microscopy allows imaging deep inside intact tissue, bringing great insight into the structural and functional dynamics of cells in their physiological environment. At the nanoscale, the complex ultrastructure of a cell's environment in tissue can be reconstructed in three dimensions (3D) using serial block face scanning electron microscopy (SBF-SEM). This provides a snapshot of high resolution structural information pertaining to the shape, organization, and localization of multiple subcellular structures at the same time. The pairing of these two imaging modalities in the same specimen provides key information to relate cellular dynamics to the ultrastructural environment. Until recently, approaches to relocate a region of interest (ROI) in tissue from 2P microscopy for SBF-SEM have been inefficient or unreliable. However, near-infrared branding (NIRB) overcomes this by using the laser from a multiphoton microscope to create fiducial markers for accurate correlation of 2P and electron microscopy (EM) imaging volumes. The process is quick and can be user defined for each sample. Here, to increase the efficiency of ROI relocation, multiple NIRB marks are used in 3D to target ultramicrotomy. A workflow is described and discussed to obtain a data set for 3D correlated light and electron microscopy, using three different preparations of brain tissue as examples. Copyright © 2017 Elsevier Inc. All rights reserved.

Production of excited nitrogen atoms and ions by electron impact on nitrogen molecules

International Nuclear Information System (INIS)

Rall, D.L.A.; Anderson, L.W.; Lin, C.C.; Sharpton, F.A.

1984-01-01

Emission lines of the N atoms and N ions are produced by electron-beam dissociative excitation of N 2 molecules. The ns→3 /sub p/ (n=5 to 9), np→3s (n=3 to 7), nd→3 /sub p/ (n=4 to 8), nf→3d (n=4,5) transitions of N and the 3 /sub p/ →3s, 3d→3p, 4s→3p, 4p→3d, 4f→3d transitions of N + have been observed and optical emission cross sections at various incident electron energies have been measured. The energy dependence of the cross sections of the N emission lines is similar to that of the N + lines at high incident electron energies, but the low-energy behaviors are quite different. These features are explained by the mechanisms involved in the production of the excited N atoms and N + ions. Absolute optical emission cross sections for the N and N + lines are presented

Processing-in-Memory Enabled Graphics Processors for 3D Rendering

Energy Technology Data Exchange (ETDEWEB)

Xie, Chenhao; Song, Shuaiwen; Wang, Jing; Zhang, Weigong; Fu, Xin

2017-02-06

The performance of 3D rendering of Graphics Processing Unit that convents 3D vector stream into 2D frame with 3D image effects significantly impact users’ gaming experience on modern computer systems. Due to the high texture throughput in 3D rendering, main memory bandwidth becomes a critical obstacle for improving the overall rendering performance. 3D stacked memory systems such as Hybrid Memory Cube (HMC) provide opportunities to significantly overcome the memory wall by directly connecting logic controllers to DRAM dies. Based on the observation that texel fetches significantly impact off-chip memory traffic, we propose two architectural designs to enable Processing-In-Memory based GPU for efficient 3D rendering.

The use of electron beam in RIA R and D

International Nuclear Information System (INIS)

Gomes, Itacil C.; Nolen, Jerry; Reed, Claude

2004-01-01

This paper discusses two electron beam applications for the RIA (Rare Isotope Accelerator) R and D. The first is for simulating energy deposition of heavy ions on lithium jets. The peak energy deposition for a 400-kW uranium beam will be 4 MW/cm 3 . Calculations have shown that a 1-MeV electron beam with 40mA of current has a peak energy deposition about 4 MW/cm 3 making it suitable to mimic the thermal response of lithium jet at that uranium beam heat load. The second application of electron beams for RIA R and D, discussed in this paper, is the use of low energy electron beam as a diagnosis tool for on-line monitoring of thickness variations of thin foils or thin jets. Thin foils can be corroded and jets might experience instabilities that can compromise their functionality. Low energy electron beams can be used to detect any change in thickness enabling a continuous on-line monitoring of the thin film being monitored. Calculations have indicated that variations in lithium jet thicknesses at the micron level can easily be detected

Proposal of custom made wrist orthoses based on 3D modelling and 3D printing.

Science.gov (United States)

Abreu de Souza, Mauren; Schmitz, Cristiane; Marega Pinhel, Marcelo; Palma Setti, Joao A; Nohama, Percy

2017-07-01

Accessibility to three-dimensional (3D) technologies, such as 3D scanning systems and additive manufacturing (like 3D printers), allows a variety of 3D applications. For medical applications in particular, these modalities are gaining a lot of attention enabling several opportunities for healthcare applications. The literature brings several cases applying both technologies, but none of them focus on the spreading of how this technology could benefit the health segment. This paper proposes a new methodology, which employs both 3D modelling and 3D printing for building orthoses, which could better fit the demands of different patients. Additionally, there is an opportunity for sharing expertise, as it represents a trendy in terms of the maker-movement. Therefore, as a result of the proposed approach, we present a case study based on a volunteer who needs an immobilization orthosis, which was built for exemplification of the whole process. This proposal also employs freely available 3D models and software, having a strong social impact. As a result, it enables the implementation and effective usability for a variety of built to fit solutions, hitching useful and smarter technologies for the healthcare sector.

Dynamic pulse buckling of cylindrical shells under axial impact: A benchmark study of 2D and 3D finite element calculations

International Nuclear Information System (INIS)

Hoffman, E.L.; Ammerman, D.J.

1995-01-01

A series of tests investigating dynamic pulse buckling of a cylindrical shell under axial impact is compared to several 2D and 3D finite element simulations of the event. The purpose of the work is to investigate the performance of various analysis codes and element types on a problem which is applicable to radioactive material transport packages, and ultimately to develop a benchmark problem to qualify finite element analysis codes for the transport package design industry. During the pulse buckling tests, a buckle formed at each end of the cylinder, and one of the two buckles became unstable and collapsed. Numerical simulations of the test were performed using PRONTO, a Sandia developed transient dynamics analysis code, and ABAQUS/Explicit with both shell and continuum elements. The calculations are compared to the tests with respect to deformed shape and impact load history

Measuring surface topography with scanning electron microscopy. I. EZEImage: a program to obtain 3D surface data.

Science.gov (United States)

Ponz, Ezequiel; Ladaga, Juan Luis; Bonetto, Rita Dominga

2006-04-01

Scanning electron microscopy (SEM) is widely used in the science of materials and different parameters were developed to characterize the surface roughness. In a previous work, we studied the surface topography with fractal dimension at low scale and two parameters at high scale by using the variogram, that is, variance vs. step log-log graph, of a SEM image. Those studies were carried out with the FERImage program, previously developed by us. To verify the previously accepted hypothesis by working with only an image, it is indispensable to have reliable three-dimensional (3D) surface data. In this work, a new program (EZEImage) to characterize 3D surface topography in SEM has been developed. It uses fast cross correlation and dynamic programming to obtain reliable dense height maps in a few seconds which can be displayed as an image where each gray level represents a height value. This image can be used for the FERImage program or any other software to obtain surface topography characteristics. EZEImage also generates anaglyph images as well as characterizes 3D surface topography by means of a parameter set to describe amplitude properties and three functional indices for characterizing bearing and fluid properties.

Measurement and calculation of excitation cross sections and level ionization by electron impact

International Nuclear Information System (INIS)

Blanco Rames, F.

1990-01-01

The experimental and theoretical study of the atomic structure in neutral noble gases is studied in this work. It mainly deals with the determination of total cross sections by electron impact and transition probabilities, including: Chapter 1: Theoretical introduction and the intermediate coupling description obtained for 420 levels of s, p and d configurations in neutral noble gases. Chapter 2: Experimental and theoretical values for electron collision cross sections are obtained for several levels of He, Ne, Ar and Kr. Our results as well as those available from existing bibliography are sumarized and compared. By means of an intermediate coupling treatment a number of regularities is found that provides us with some useful approximate semi empirical expressions. Chapter 3: Determination of lifetime and transition probabilities. Lifetime measurements are carried out by means of laser excitation and multichannel delayed coincidences technique. The experimental setup and electronics are also described. Chapter 4: Details the experimental setup developed for electron cross sections measurement by the optical method. The difficulties of this method and their treatment are also shown. (Author)

Excitation of the (2p2)1D and (2s2p)1P autoionizing states of helium by 200 eV electron impact

International Nuclear Information System (INIS)

Godunov, A.L.; McGuire, J.H.; Schipakov, V.S.; Crowe, A.

2002-01-01

We report full second Born calculations with inclusion of post-collision interactions for excitation of the (2p 2 ) 1 D and (2s2p) 1 P autoionizing states of helium by 200 eV electron impact. The calculations are compared to (e, 2e) measurements of McDonald and Crowe (McDonald D G and Crowe A 1993 J. Phys. B: At. Mol. Opt. Phys. 26 2887-97) and Lower and Weigold (Lower J and Weigold E 1990 J. Phys. B: At. Mol. Opt. Phys. 23 2819-45). It is shown that post-collision interactions or Coulomb interactions in the final state between the scattered particle, the ejected electron and the recoil ion have a strong influence on both the direct ionization and resonance profiles around the binary lobe. The second-order terms in the amplitude of double electron excitation also play an observable role under these kinematic conditions. Reasonable agreement is found between the full-scale calculations and the experimental data. (author). Letter-to-the-editor

Electron-triggered chemistry in HNO3/H2O complexes

Czech Academy of Sciences Publication Activity Database

Lengyel, Jozef; Ončák, M.; Fedor, Juraj; Kočišek, Jaroslav; Pysanenko, Andriy; Beyer, M. K.; Fárník, Michal

2017-01-01

Roč. 19, č. 19 (2017), s. 11753-11758 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GA15-12386S Institutional support: RVO:61388955 Keywords : electron-triggered chemistry * acid-water clusters * gas-phase reactions Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.123, year: 2016

Impact of MoO3 interlayer on the energy level alignment of pentacene-C60 heterostructure.

Science.gov (United States)

Zou, Ye; Mao, Hongying; Meng, Qing; Zhu, Daoben

2016-02-28

Using in situ ultraviolet photoelectron spectroscopy, the electronic structure evolutions at the interface between pentacene and fullerene (C60), a classical organic donor-acceptor heterostructure in organic electronic devices, on indium-tin oxide (ITO) and MoO3 modified ITO substrates have been investigated. The insertion of a thin layer MoO3 has a significant impact on the interfacial energy level alignment of pentacene-C60 heterostructure. For the deposition of C60 on pentacene, the energy difference between the highest occupied molecular orbital of donor and the lowest unoccupied molecular orbital of acceptor (HOMO(D)-LUMO(A)) offset of C60/pentacene heterostructure increased from 0.86 eV to 1.54 eV after the insertion of a thin layer MoO3 on ITO. In the inverted heterostructrure where pentacene was deposited on C60, the HOMO(D)-LUMO(A) offset of pentacene/C60 heterostructure increased from 1.32 to 2.20 eV after MoO3 modification on ITO. The significant difference of HOMO(D)-LUMO(A) offset shows the feasibility to optimize organic electronic device performance through interfacial engineering approaches, such as the insertion of a thin layer high work function MoO3 films.

Impact of DIY Home Manufacturing with 3D Printing on the Toy and Game Market

Directory of Open Access Journals (Sweden)

Emily E. Petersen

2017-07-01

Full Text Available The 2020 toy and game market is projected to be US$135 billion. To determine if 3D printing could affect these markets if consumers offset purchases by 3D printing free designs, this study investigates the 100 most popular downloaded designs at MyMiniFactory in a month. Savings are quantified for using a Lulzbot Mini 3D printer and three filament types: commercial filament, pellet-extruded filament, and post-consumer waste converted to filament with a recyclebot. Case studies probed the quality of: (1 six common complex toys; (2 Lego blocks; and (3 the customizability of open source board games. All filaments analyzed saved the user over 75% of the cost of commercially available true alternative toys and over 90% for recyclebot filament. Overall, these results indicate a single 3D printing repository among dozens is saving consumers well over $60 million/year in offset purchases. The most common savings fell by 40%–90% in total savings, which came with the ability to make novel toys and games. The results of this study show consumers can generate higher value items for less money using the open source distributed manufacturing paradigm. It appears clear that consumer do-it-yourself (DIY manufacturing is set to have a significant impact on the toy and game markets in the future.

Low-Power Receive-Electronics for a Miniature 3D Ultrasound Probe

NARCIS (Netherlands)

Yu, Z.

2012-01-01

This thesis describes the design of a front-end application-specific integrated circuit (ASIC), which will be put into the tip of a miniature ultrasound probe for 3D Trans-Esophageal Echocardiography (TEE). To enable 3D TEE, a matrix piezoelectric ultrasound transducer with more than 2000 elements

Observation of reduction of secondary electron emission from helium ion impact due to plasma-generated nanostructured tungsten fuzz

International Nuclear Information System (INIS)

Hollmann, E M; Doerner, R P; Nishijima, D; Pigarov, A Yu

2017-01-01

Growth of nanostructured fuzz on a tungsten target in a helium plasma is found to cause a significant (∼3×) reduction in ion impact secondary electron emission in a linear plasma device. The ion impact secondary electron emission is separated from the electron impact secondary electron emission by varying the target bias voltage and fitting to expected contributions from electron impact, both thermal and non-thermal; with the non-thermal electron contribution being modeled using Monte-Carlo simulations. The observed (∼3×) reduction is similar in magnitude to the (∼2×) reduction observed in previous work for the effect of tungsten fuzz formation on secondary electron emission due to electron impact. It is hypothesized that the observed reduction results from re-absorption of secondary electrons in the tungsten fuzz. (paper)

Why 3D Print? The 21st-Century Skills Students Develop While Engaging in 3D Printing Projects

Science.gov (United States)

Trust, Torrey; Maloy, Robert W.

2017-01-01

The emergence of 3D printing has raised hopes and concerns about how it can be used effectively as an educational technology in school classrooms. This paper presents the results of a survey asking teachers from multiple grade levels and subject fields about the impact of 3D projects on student learning. Teachers were asked about the kinds of 3D…

Orbital-Specific observation of O2p and Ni3d electrons in LiNi0.5Mn0.5O2, a cathode material for lithium-ion batteries

Science.gov (United States)

Satou, Yoshinori; Komine, Shigeki; Shimizu, Sumera

2017-09-01

Cathode materials for lithium-ion batteries containing Ni2+ have attracted much interest because of their high theoretical capacity. However, the precise electronic structures of these cathode materials have not yet been clearly observed, especially the energy positions of the O2p and Ni3d orbitals and the shape of the density of states. The aim of this study was to investigate the relative energy positions and shape of the density of states of O2p and Ni3d for LiNi0.5Mn0.5O2 experimentally. We cleaved a LiNi0.5Mn0.5O2 pellet in an Ar-filled glove box and performed synchrotron ultraviolet photoelectron spectroscopy for different photon energies, which enabled us to investigate the relative cross-section intensity of O2p and Ni3d. As a result, the valence-band structure was determined. We found that O2p electrons are itinerant and exist in the vicinity of the Fermi energy more than Ni3d electrons. Ni3d electrons are more localized and spread mainly from 1.2-1.5 eV below the Fermi energy. To validate the electronic structure, we measured the synchrotron O K-edge X-ray absorption fine structure of electrochemically lithium-extracted LiNi0.5Mn0.5O2. The electronic structure demonstrated that ligand holes in the oxygen atoms form below the Fermi level during the initial stage of Li extraction and that the formation rate of the holes decreases with Li extraction.

Association of intracellular and synaptic organization in cochlear inner hair cells revealed by 3D electron microscopy

OpenAIRE

Bullen, Anwen; West, Timothy; Moores, Carolyn; Ashmore, Jonathan; Fleck, Roland A.; MacLellan-Gibson, Kirsty; Forge, Andrew

2015-01-01

ABSTRACT The ways in which cell architecture is modelled to meet cell function is a poorly understood facet of cell biology. To address this question, we have studied the cytoarchitecture of a cell with highly specialised organisation, the cochlear inner hair cell (IHC), using multiple hierarchies of three-dimensional (3D) electron microscopy analyses. We show that synaptic terminal distribution on the IHC surface correlates with cell shape, and the distribution of a highly organised network ...

Electronic and magnetic properties of 3d-metal trioxides superhalogen cluster-doped monolayer MoS2: A first-principles study

International Nuclear Information System (INIS)

Li, Dan; Niu, Yuan; Zhao, Hongmin; Liang, Chunjun; He, Zhiqun

2014-01-01

Utilizing first-principle calculations, the structural, electronic, and magnetic properties of monolayer MoS 2 doped with 3d transition-metal (TM) atoms and 3d-metal trioxides (TMO 3 ) superhalogen clusters are investigated. 3d-metal TMO 3 superhalogen cluster-doped monolayers MoS 2 almost have negative formation energies except CoO 3 and NiO 3 doped monolayer MoS 2 , which are much lower than those of 3d TM-doped structures. 3d-metal TMO 3 superhalogen clusters are more easily embedded in monolayer MoS 2 than 3d-metal atoms. MnO 3 , FeO 3 , CoO 3 , and NiO 3 incorporated into monolayer MoS 2 are magnetic, and the total magnetic moments are approximately 1.0, 2.0, 3.0, and 4.0 μB per supercell, respectively. MnO 3 and FeO 3 incorporated into monolayer MoS 2 become semiconductors, whereas CoO 3 and NiO 3 incorporated into monolayer MoS 2 become half-metallic. Our studies demonstrate that the half-metallic ferromagnetic nature of 3d-metal TMO 3 superhalogen clusters-doped monolayer MoS 2 has a great potential for MoS 2 -based spintronic device applications. -- Highlights: •TMO 3 superhalogen clusters incorporated into monolayer MoS 2 were investigated. •TMO 3 doped structures have much lower formation energies than TM doped structures. •TMO 3 cluster-doped MoS 2 are thermodynamically favored. •Significant charge transfers between O atoms and Mo atoms in TMO 3 doped structures. •MnO 3 , FeO 3 , CoO 3 , and NiO 3 incorporated into monolayer MoS 2 are magnetic.

Runaway electron mitigation by 3D fields in the ASDEX-Upgrade experiment

Science.gov (United States)

Gobbin, M.; Li, L.; Liu, Y. Q.; Marrelli, L.; Nocente, M.; Papp, G.; Pautasso, G.; Piovesan, P.; Valisa, M.; Carnevale, D.; Esposito, B.; Giacomelli, L.; Gospodarczyk, M.; McCarthy, P. J.; Martin, P.; Suttrop, W.; Tardocchi, M.; Teschke, M.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

2018-01-01

Disruption-generated runaway electron (RE) beams represent a severe threat for tokamak plasma-facing components in high current devices like ITER, thus motivating the search of mitigation techniques. The application of 3D fields might aid this purpose and recently was investigated also in the ASDEX Upgrade experiment by using the internal active saddle coils (termed B-coils). Resonant magnetic perturbations (RMPs) with dominant toroidal mode number n = 1 have been applied by the B-coils, in a RE specific scenario, before and during disruptions, which are deliberately created via massive gas injection. The application of RMPs affects the electron temperature profile and seemingly changes the dynamics of the disruption; this results in a significantly reduced current and lifetime of the generated RE beam. A similar effect is observed also in the hard-x-ray (HXR) spectrum, associated to RE emission, characterized by a partial decrease of the energy content below 1 MeV when RMPs are applied. The strength of the observed effects strongly depends on the upper-to-lower B-coil phasing, i.e. on the poloidal spectrum of the applied RMPs, which has been reconstructed including the plasma response by the code MARS-F. A crude vacuum approximation fails in the interpretation of the experimental findings: despite the relatively low β (< 0.5 % ) of these discharges, a modest amplification (factor of 2) of the edge kink response occurs, which has to be considered to explain the observed suppression effects.

Preliminary report on electron energy-loss measurements for CCl3, CCl2F2, CCl3F

International Nuclear Information System (INIS)

Bushnell, D.L. Jr.; Huebner, R.H.; Celotta, R.J.; Mielczarek, S.R.

1975-01-01

Currently, nation-wide research efforts are devoted to studying the possible ozone (O 3 ) depletion in the stratosphere by the chemical action of chlorine atoms released from CCl 2 F 2 or CCl 3 F upon absorption of ultraviolet radiation. Since electron-impact data taken in the forward scattering direction can be used to derive oscillator strengths and thus to yield apparent photoabsorption cross sections, such an analysis for CCl 2 F 2 , CCLl 3 F, and CClF 3 was carried out. Oscillator-strength distributions were obtained between 5 and 20 eV and are compared to available photoabsorption data. Certain photoabsorption values agree very well with these electron-impact data, but other optical studies deviate in some spectral regions by as much as a factor of 5. Also, the electron energy-loss spectrum reveals electronic transitions previously undetected by photoabsorption

Electron impact excitation of the n = 2 to n = 3 transition in atomic hydrogen near threshold

Science.gov (United States)

Hata, J.; Morgan, L. A.; McDowell, M. R. C.

1980-06-01

Close-coupling calculations of electron impact excitation of the n = 2 to n = 3 transition of atomic hydrogen at energies below the n = 4 threshold are presented. The algebraic variational close-coupling code of Morgan (1980) with an eighteen-state basis was used to obtain cross sections at eight impact energies from 2.04 to 2.45 eV, and calculations in a six-state close-coupling model were compared with the six-state calculations of Burke et al. (1967). The six-state values are found to be in satisfactory agreement with the exception of the singlet contribution to the 2s-3s transition. Near the n = 3 threshold the cross section obtained in the full calculation is found to be almost a factor of 2 lower than that predicted by Johnson (1972), thus explaining in part the discrepancy between Johnson's results and experiments on hydrogen plasmas. Estimates of rate coefficients based on the cross sections and assuming a Maxwellian velocity distribution, however, are shown to remain in disagreement with experiment.

3D assembly of carbon nanotubes for fabrication of field-effect transistors through nanomanipulation and electron-beam-induced deposition

International Nuclear Information System (INIS)

Yu, Ning; Shi, Qing; Wang, Huaping; Huang, Qiang; Fukuda, Toshio; Nakajima, Masahiro; Yang, Zhan; Sun, Lining

2017-01-01

Three-dimensional carbon nanotube field-effect transistors (3D CNTFETs) possess predictable characteristics that rival those of planar CNTFETs and Si-based MOSFETs. However, due to the lack of a reliable assembly technology, they are rarely reported on, despite the amount of attention they receive. To address this problem, we propose the novel concept of a 3D CNTFET and develop its assembly strategy based on nanomanipulation and the electron-beam-induced deposition (EBID) technique inside a scanning electron microscope (SEM). In particular, the electrodes in our transistor design are three metallic cuboids of the same size, and their front, top and back surfaces are all wrapped up in CNTs. The assembly strategy is employed to build the structure through a repeated basic process of pick-up, placement, fixing and cutting of CNTs. The pick-up and placement is performed through one nanomanipulator with four degrees of freedom. Fixing is carried out through the EBID technique so as to improve the mechanical and electrical characteristics of the CNT/electrodes connection. CNT cutting is undertaken using the typical method of electrical breakdown. Experimental results showed that two CNTs were successfully assembled on the front sides of the cubic electrodes. This validates our assembly method for the 3D CNTFET. Also, when contact resistance was measured, tens of kilohms of resistance was observed at the CNT-EBID deposition-FET electrodes junction.. This manifests the electrical reliability of our assembly strategy. (paper)

3D IC for future HEP detectors

International Nuclear Information System (INIS)

Thom, J; Badman, R; Lipton, R; Johnson, M; Spiegel, L; Deptuch, G; Ye, Z; Heintz, U; Narain, M; Triphati, M; Kenney, C; Parker, S; Siddons, D P

2014-01-01

Three dimensional integrated circuit technologies offer the possibility of fabricating large area arrays of sensors integrated with complex electronics with minimal dead area, which makes them ideally suited for applications at the LHC upgraded detectors and other future detectors. We describe ongoing R and D efforts to demonstrate functionality of components of such detectors. This includes the study of integrated 3D electronics with active edge sensors to produce ''active tiles'' which can be tested and assembled into arrays of arbitrary size with high yield

Electron-triggered chemistry in HNO3/H2O complexes

Czech Academy of Sciences Publication Activity Database

Lengyel, Jozef; Ončák, M.; Fedor, Juraj; Kočišek, Jaroslav; Pysanenko, Andriy; Beyer, M. K.; Fárník, Michal

2017-01-01

Roč. 19, č. 19 (2017), s. 11753-11758 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GA15-12386S Institutional support: RVO:61388955 Keywords : electron-triggered chemistry * acid-water clusters * gas-phase reaction s Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.123, year: 2016

Use of 3D printers to create a patient‐specific 3D bolus for external beam therapy

Science.gov (United States)

Baker, Jamie; Hsia, An Ting; Xu, Zhigang

2015-01-01

The purpose of this paper is to demonstrate that an inexpensive 3D printer can be used to manufacture patient‐specific bolus for external beam therapy, and to show we can accurately model this printed bolus in our treatment planning system for accurate treatment delivery. Percent depth‐dose measurements and tissue maximum ratios were used to determine the characteristics of the printing materials, acrylonitrile butadiene styrene and polylactic acid, as bolus material with physical density of 1.04 and 1.2 g/cm3, and electron density of 3.38×1023electrons/cm3 and 3.80×1023 electrons/cm3, respectively. Dose plane comparisons using Gafchromic EBT2 film and the RANDO phantom were used to verify accurate treatment planning. We accurately modeled a printing material in Eclipse treatment planning system, assigning it a Hounsfield unit of 260. We were also able to verify accurate treatment planning using gamma analysis for dose plane comparisons. With gamma criteria of 5% dose difference and 2 mm DTA, we were able to have 86.5% points passing, and with gamma criteria of 5% dose difference and 3 mm DTA, we were able to have 95% points passing. We were able to create a patient‐specific bolus using an inexpensive 3D printer and model it in our treatment planning system for accurate treatment delivery. PACS numbers: 87.53.Jw, 87.53.Kn, 87.56.ng PMID:26103485

Analysis of the electronic structures of 3d transition metals doped CuGaS2 based on DFT calculations