WorldWideScience

Sample records for vertical electronic spectrum

  1. Effects of the molecular structure on the electronic vertical spectrum of oxoglaucine

    Directory of Open Access Journals (Sweden)

    Martha Cecilia Daza Espinosa

    2018-01-01

    Full Text Available The vertical electronic spectrum of oxoglaucine by means of a multireference configuration interaction method (DFT/MRCI was studied. The effect of both methyl and methoxy groups on the geometries and energetic distribution of the low-lying excited states was analyzed. The results show that, by means of the TZVP basis set, at the ground state minima of oxoglaucine, oxoglaucine without methyl and methoxy groups, the lowest excited singlet states are of nπ* (S1 and ππ* (S2 type. Triplet states of ππ* (T1 and nπ* (T2 type are energetically accessible from S1. From the energetic point of view, it can be proposed that the channel for an efficient intersystem crossing 1(nπ*⇝3(ππ* is plausible. Although the presence of the methyl and methoxyl groups distort the planarity of the rings system, the effect in the vertical distribution of the lowest lying singlet and triplet states can be considered as negligible.

  2. Vertical Footbridge Vibrations: The Response Spectrum Methodology

    DEFF Research Database (Denmark)

    Georgakis, Christos; Ingólfsson, Einar Thór

    2008-01-01

    In this paper, a novel, accurate and readily codifiable methodology for the prediction of vertical footbridge response is presented. The methodology is based on the well-established response spectrum approach used in the majority of the world’s current seismic design codes of practice. The concept...... of a universally applicable reference response spectrum is introduced, from which the pedestrian-induced vertical response of any footbridge may be determined, based on a defined “event” and the probability of occurrence of that event. A series of Monte Carlo simulations are undertaken for the development...... of a reference response spectrum. The simulations use known statistical data for pedestrian and population walking characteristics to generate loads for a 50m long simply-supported bridge, with a fixed level of damping and a mean pedestrian flow rate of 1 pedestrian / sec. The response obtained from...

  3. A one-electron model for the aqueous electron that includes many-body electron-water polarization: Bulk equilibrium structure, vertical electron binding energy, and optical absorption spectrum.

    Science.gov (United States)

    Jacobson, Leif D; Herbert, John M

    2010-10-21

    Previously, we reported an electron-water pseudopotential designed to be used in conjunction with a polarizable water model, in order to describe the hydrated electron [L. D. Jacobson et al., J. Chem. Phys. 130, 124115 (2009)]. Subsequently, we found this model to be inadequate for the aqueous electron in bulk water, and here we report a reparametrization of the model. Unlike the previous model, the current version is not fit directly to any observables; rather, we use an ab initio exchange-correlation potential, along with a repulsive potential that is fit to reproduce the density maximum of the excess electron's wave function within the static-exchange approximation. The new parametrization performs at least as well as the previous model, as compared to ab initio benchmarks for (H(2)O)(n) (-) clusters, and also predicts reasonable values for the diffusion coefficient, radius of gyration, and absorption maximum of the bulk species. The new model predicts a vertical electron binding energy of 3.7 eV in bulk water, which is 1.4 eV smaller than the value obtained using nonpolarizable models; the difference represents the solvent's electronic reorganization energy following electron detachment. We find that the electron's first solvation shell is quite loose, which may be responsible for the electron's large, positive entropy of hydration. Many-body polarization alters the electronic absorption line shape in a qualitative way, giving rise to a high-energy tail that is observed experimentally but is absent in previous simulations. In our model, this feature arises from spatially diffuse excited states that are bound only by electronic reorganization (i.e., solvent polarization) following electronic excitation.

  4. Electronic spectrum of 9-methylanthracenium radical cation

    Energy Technology Data Exchange (ETDEWEB)

    O’Connor, Gerard D.; Schmidt, Timothy W., E-mail: timothy.schmidt@unsw.edu.au [School of Chemistry, UNSW Sydney, New South Wales 2052 (Australia); Sanelli, Julian A.; Dryza, Vik; Bieske, Evan J. [School of Chemistry, The University of Melbourne, Victoria 3010 (Australia)

    2016-04-21

    The predissociation spectrum of the cold, argon-tagged, 9-methylanthracenium radical cation is reported from 8000 cm{sup −1} to 44 500 cm{sup −1}. The reported spectrum contains bands corresponding to at least eight electronic transitions ranging from the near infrared to the ultraviolet. These electronic transitions are assigned through comparison with ab initio energies and intensities. The infrared D{sub 1}←D{sub 0} transitions exhibit significant vibronic activity, which is assigned through comparison with TD-B3LYP excited state frequencies and intensities, as well as modelled vibronic interactions. Dissociation of 9-methylanthracenium is also observed at high visible-photon energies, resulting in the loss of either CH{sub 2} or CH{sub 3}. The relevance of these spectra, and the spectra of other polycyclic aromatic hydrocarbon radical cations, to the largely unassigned diffuse interstellar bands, is discussed.

  5. Electron Ionization Mass Spectrum of Tellurium Hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Richard A.; McNamara, Bruce K.; Barinaga, Charles J.; Peterson, James M.; Govind, Niranjan; Andersen, Amity; Abrecht, David G.; Schwantes, Jon M.; Ballou, Nathan E.

    2015-05-18

    The first electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5+, TeF4+ TeF3+, TeF2+, TeF1+, and Te+, Te2+. A trend in increasing abundance was observed for the even fluoride bearing ions: TeF1+ < TeF3+ < TeF5+, and a decreasing abundance was observed for the even fragment series: Te(0)+ > TeF2+ > TeF4+ > TeF6+, with the molecular ion TeF6+ not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6+.

  6. Determination of the number of Vertical Axis Wind Turbine blades based on power spectrum

    Science.gov (United States)

    Fedak, Waldemar; Anweiler, Stanisław; Gancarski, Wojciech; Ulbrich, Roman

    2017-10-01

    Technology of wind exploitation has been applied widely all over the world and has already reached the level in which manufacturers want to maximize the yield with the minimum investment outlays. The main objective of this paper is the determination of the optimal number of blades in the Cup-Bladed Vertical Axis Wind Turbine. Optimizing the size of the Vertical Axis Wind Turbine allows the reduction of costs. The maximum power of the rotor is selected as the performance target. The optimum number of Vertical Axis Wind Turbine blades evaluation is based on analysis of a single blade simulation and its superposition for the whole rotor. The simulation of working blade was done in MatLab environment. Power spectrum graphs were prepared and compared throughout superposition of individual blades in the Vertical Axis Wind Turbine rotor. The major result of this research is the Vertical Axis Wind Turbine power characteristic. On the basis of the analysis of the power spectra, optimum number of the blades was specified for the analysed rotor. Power spectrum analysis of wind turbine enabled the specification of the optimal number of blades, and can be used regarding investment outlays and power output of the Vertical Axis Wind Turbine.

  7. Vertical footbridge vibrations: details regarding and experimental validation of the response spectrum methodology

    DEFF Research Database (Denmark)

    Ingólfsson, Einar Thór; Georgakis, Christos; Svendsen, Martin Nymann

    2008-01-01

    seismic design codes of practice. A basic outline of the methodology is given, followed by a detailed examination of the bridge-specific parameters that are applied to adjust the response obtained from a universal reference design spectrum. The bridge-specific parameters take into account key variations......In this paper, details regarding and the experimental validation of the “response spectrum” methodology for the determination of vertical footbridge response are presented. The methodology is inspired by the well-established response spectrum approach used in the majority of the world’s current...... footbridge, are presented. An accurate representation of the random crowd loading during the experiments is created through video-footage and used to theoretically predict the vertical bridge response following the response spectrum methodology. The predictions verify the effectiveness of the methodology...

  8. Electron-electron interaction, weak localization and spin valve effect in vertical-transport graphene devices

    Energy Technology Data Exchange (ETDEWEB)

    Long, Mingsheng; Gong, Youpin; Wei, Xiangfei; Zhu, Chao; Xu, Jianbao; Liu, Ping; Guo, Yufen; Li, Weiwei; Liu, Liwei, E-mail: lwliu2007@sinano.ac.cn [Key Laboratory of Nanodevices and Applications-CAS and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China); Liu, Guangtong [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-04-14

    We fabricated a vertical structure device, in which graphene is sandwiched between two asymmetric ferromagnetic electrodes. The measurements of electron and spin transport were performed across the combined channels containing the vertical and horizontal components. The presence of electron-electron interaction (EEI) was found not only at low temperatures but also at moderate temperatures up to ∼120 K, and EEI dominates over weak localization (WL) with and without applying magnetic fields perpendicular to the sample plane. Moreover, spin valve effect was observed when magnetic filed is swept at the direction parallel to the sample surface. We attribute the EEI and WL surviving at a relatively high temperature to the effective suppress of phonon scattering in the vertical device structure. The findings open a way for studying quantum correlation at relatively high temperature.

  9. Electron energy spectrum in core-shell elliptic quantum wire

    Directory of Open Access Journals (Sweden)

    V.Holovatsky

    2007-01-01

    Full Text Available The electron energy spectrum in core-shell elliptic quantum wire and elliptic semiconductor nanotubes are investigated within the effective mass approximation. The solution of Schrodinger equation based on the Mathieu functions is obtained in elliptic coordinates. The dependencies of the electron size quantization spectrum on the size and shape of the core-shell nanowire and nanotube are calculated. It is shown that the ellipticity of a quantum wire leads to break of degeneration of quasiparticle energy spectrum. The dependences of the energy of odd and even electron states on the ratio between semiaxes are of a nonmonotonous character. The anticrosing effects are observed at the dependencies of electron energy spectrum on the transversal size of the core-shell nanowire.

  10. Time-Resolved Electron Spectrum Measurements on the Felix Facility

    NARCIS (Netherlands)

    Gillespie, W. A.; Martin, P. F.; MacLeod, A. M.; Macdonald, A. J.; Bakker, R. J.; van der Geer, C. A. J.; van der Meer, A. F. G.; van Amersfoort, P. W.

    1993-01-01

    Measurements of the FELIX electron energy spectrum using multichannel secondary emission monitors are described. The detectors have a time resolution of 50 ns and span typically 4% in electron energy over 32 channels. Aspects of the design of the OTR detector and energy spectrometer for FELIX are

  11. Systematics in the Electron Spectrum Measured by ATIC

    Science.gov (United States)

    Panov, A. D.; Zatsepin, V. I.; Sokolskaya, N. V.; Adams, J. H., Jr.; Ahn, H. S.; Bashindzhagyan, G. L.; Chang, J.; Christl, M.; Guzik, T. G.; Isbert, J.; hide

    2009-01-01

    An analysis of different parameters to separate electrons from protons in the ATIC experiment has been performed. Five separate discriminants were studied by different Monte Carlo programs, leading to a variety of results. Application to the ATIC data indicates the range of variation possible in the interpretation of the data. The results of this analysis, when compared with the published results [5], show good agreement in the most interesting region of energy (from 90 GeV to 600 GeV). The measured electron spectrum is compared with the recent data reported by Fermi/LAT, and there is no major disagreement between ATIC s results and Fermi/LAT. Finally, possible systematics-free, short energy scale features of the ATIC electron spectrum are mentioned. Keywords: ATIC, electron spectrum, fine structure

  12. Measuring the orbital angular momentum spectrum of an electron beam

    Science.gov (United States)

    Grillo, Vincenzo; Tavabi, Amir H.; Venturi, Federico; Larocque, Hugo; Balboni, Roberto; Gazzadi, Gian Carlo; Frabboni, Stefano; Lu, Peng-Han; Mafakheri, Erfan; Bouchard, Frédéric; Dunin-Borkowski, Rafal E.; Boyd, Robert W.; Lavery, Martin P. J.; Padgett, Miles J.; Karimi, Ebrahim

    2017-01-01

    Electron waves that carry orbital angular momentum (OAM) are characterized by a quantized and unbounded magnetic dipole moment parallel to their propagation direction. When interacting with magnetic materials, the wavefunctions of such electrons are inherently modified. Such variations therefore motivate the need to analyse electron wavefunctions, especially their wavefronts, to obtain information regarding the material's structure. Here, we propose, design and demonstrate the performance of a device based on nanoscale holograms for measuring an electron's OAM components by spatially separating them. We sort pure and superposed OAM states of electrons with OAM values of between −10 and 10. We employ the device to analyse the OAM spectrum of electrons that have been affected by a micron-scale magnetic dipole, thus establishing that our sorter can be an instrument for nanoscale magnetic spectroscopy. PMID:28537248

  13. Spectrum and Charge Ratio of Vertical Cosmic Ray Muons up to Momenta of 2.5 TeV/c

    Energy Technology Data Exchange (ETDEWEB)

    Schmelling, M.; /Heidelberg, Max Planck Inst.; Hashim, N.O.; /Kenyatta U. Coll.; Grupen, C.; /Siegen U.; Luitz, S.; /SLAC; Maciuc, F.; /Heidelberg, Max Planck Inst.; Mailov, A.; /Siegen U.; Muller, A.-S.; /Karlsruhe, Inst. Technol.; Sander, H.-G.; /Mainz U., Inst. Phys.; Schmeling, S.; /CERN; Tcaciuc, R.; /Siegen U.; Wachsmuth, H.; /CERN; Zuber, K.; /Dresden, Tech. U.

    2012-09-14

    The ALEPH detector at LEP has been used to measure the momentum spectrum and charge ratio of vertical cosmic ray muons underground. The sea-level cosmic ray muon spectrum for momenta up to 2.5 TeV/c has been obtained by correcting for the overburden of 320 meter water equivalent (mwe). The results are compared with Monte Carlo models for air shower development in the atmosphere. From the analysis of the spectrum the total flux and the spectral index of the cosmic ray primaries is inferred. The charge ratio suggests a dominantly light composition of cosmic ray primaries with energies up to 10{sup 15} eV.

  14. Spectrum and Charge Ratio of Vertical Cosmic Ray Muons up to Momenta of 2.5 TeV/c

    CERN Document Server

    Schmelling, M; Grupen, C; Luitz, S; Maciuc, F; Mailov, A; Müller, A -S; Sander, H -G; Schmeling, S; Tcaciuc, R; Wachsmuth, H; Zuber, K

    2013-01-01

    The ALEPH detector at LEP has been used to measure the momentum spectrum and charge ratio of vertical cosmic ray muons underground. The sea-level cosmic ray muon spectrum for momenta up to 2.5 TeV/c has been obtained by correcting for the overburden of 320 meter water equivalent (mwe). The results are compared with Monte Carlo models for air shower development in the atmosphere. From the analysis of the spectrum the total flux and the spectral index of the cosmic ray primaries is inferred. The charge ratio suggests a dominantly light composition of cosmic ray primaries with energies up to 10^15 eV.

  15. Vertically aligned multiwalled carbon nanotubes as electronic interconnects.

    OpenAIRE

    Gopee, Vimal C.

    2017-01-01

    The drive for miniaturisation of electronic circuits provides new materials challenges for the electronics industry. Indeed, the continued downscaling of transistor dimensions, described by Moore’s Law, has led to a race to find suitable replacements for current interconnect materials to replace copper. Carbon nanotubes have been studied as a suitable replacement for copper due to its superior electrical, thermal and mechanical properties. One of the advantages of using carbon nanotubes is th...

  16. Appraisal of ANN and ANFIS for Predicting Vertical Total Electron ...

    African Journals Online (AJOL)

    The propagation of the GPS signals are interfered by free electrons which are the massive particles in the ionosphere region and results in delays in the ... Artificial Neural Network (ANN) and Adaptive Neuro Fuzzy Inference System (ANFIS) algorithms have been developed for the prediction of VTEC in the ionosphere.

  17. Electronic structure analysis and vertical ionization energies of ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Results from different decouplings of the electron propagator theory using MP2/6-311g (2df,. 2p) and MP2/6-311++g (2df, 2p) optimized geometries have been performed to investigate first eight ver- tical ionization energies and the corresponding Dyson orbitals. The results computed are in good agree- ment with ...

  18. Electronic structure analysis and vertical ionization energies of ...

    Indian Academy of Sciences (India)

    Detailed examination of the -orbital density distribution of Dyson orbitals provides clarity in PES assignments and new insights about the topology of ring and ethynyl - electron density distribution which may be tapped for improved nonlinear optical/electrochemical response from the thiophenic conjugated polymers ...

  19. Vertical Silicon Nanowire Platform for Low Power Electronics and Clean Energy Applications

    Directory of Open Access Journals (Sweden)

    D.-L. Kwong

    2012-01-01

    Full Text Available This paper reviews the progress of the vertical top-down nanowire technology platform developed to explore novel device architectures and integration schemes for green electronics and clean energy applications. Under electronics domain, besides having ultimate scaling potential, the vertical wire offers (1 CMOS circuits with much smaller foot print as compared to planar transistor at the same technology node, (2 a natural platform for tunneling FETs, and (3 a route to fabricate stacked nonvolatile memory cells. Under clean energy harvesting area, vertical wires could provide (1 cost reduction in photovoltaic energy conversion through enhanced light trapping and (2 a fully CMOS compatible thermoelectric engine converting waste-heat into electricity. In addition to progress review, we discuss the challenges and future prospects with vertical nanowires platform.

  20. Evolution of quasistationary electron spectrum in open spherical quantum dot

    Directory of Open Access Journals (Sweden)

    M.V. Tkach

    2008-09-01

    Full Text Available The evolution of electron quasistationary spectrum in open spherical quantum dot is under study within the effective mass and rectangular potential model. Within the framework of the S-matrix model the exact solution of Schrödinger equation is obtained in general analytical form. It is shown, for the first time, that the generalized resonance energies and widths introduced as the parameters defining the probability distribution function (over the energy or quasi momentum of electron location in quantum dot, adequately characterize the evolution of its quasistationary states (contrary to the S-matrix poles in the whole range of barrier thickness: from zero (free states up to the infinity (stationary bound states are under the barrier and virtual and free states are above it.

  1. The electronic spectrum of the FeF radical

    CERN Document Server

    Kermode, S

    2001-01-01

    well as two previously unobserved electronic states around 5000 cm sup - sup 1 above the ground state. The states are assigned as A sup 6 PI and B sup 6 SIGMA sup + electronic states. The spin components of both electronic states were found to be heavily perturbed resulting in uneven splittings between them. A third, weak series was also observed but could not be assigned. The (0,0) band of the sup 6 PI sub 7 sub / sub 2 -B sup 6 SIGMA sub 5 sub / sub 2 transition at 398 nm was observed in absorption by laser induced fluorescence and rotational structure assigned. The spectra obtained were weak due to a low population of the B sup 6 SIGMA sup + state by the reaction used to form FeF. The levels were found to be highly perturbed at high J values. Attempts were made to fit the data on the sup 6 PI-B sup 6 SIGMA sup + system to an effective Hamiltonian, though the presence of perturbations meant that the system is not well described by such a model. The electronic spectrum of the FeF radical has been investigate...

  2. Determination of the vertical electron-density profile in ionospheric tomography: experimental results

    Directory of Open Access Journals (Sweden)

    C. N. Mitchell

    Full Text Available The reconstruction of the vertical electron-density profile is a fundamental problem in ionospheric tomography. Lack of near-horizontal ray paths limits the information available on the vertical profile, so that the resultant image of electron density is biased in a horizontal sense. The vertical profile is of great importance as it affects the authenticity of the entire tomographic image. A new method is described whereby the vertical profile is selected using relative total-electron-content measurements. The new reconstruction process has been developed from modelling studies. A range of background ionospheres, representing many possible peak heights, scale heights and electron densities are formed from a Chapman profile on the bottomside with a range of topside profiles. The iterative reconstruction process is performed on all of these background ionospheres and a numerical selection criterion employed to select the final image. The resulting tomographic images show excellent agreement in electron density when compared with independent verification provided by the EISCAT radar.

  3. Spectrum and charge ratio of vertical cosmic ray muons up to momenta of 2.5 TeV/c

    Science.gov (United States)

    Schmelling, M.; Hashim, N. O.; Grupen, C.; Luitz, S.; Maciuc, F.; Mailov, A.; Müller, A.-S.; Sander, H.-G.; Schmeling, S.; Tcaciuc, R.; Wachsmuth, H.; Ziegler, T.; Zuber, K.

    2013-09-01

    The ALEPH detector at LEP has been used to measure the momentum spectrum and charge ratio of vertical cosmic ray muons underground. The sea-level cosmic ray muon spectrum for momenta up to 2.5 TeV/c has been obtained by correcting for the overburden of 320 m water equivalent (mwe). The results are compared with Monte Carlo models for air shower development in the atmosphere. From the analysis of the spectrum the total flux and the spectral index of the cosmic ray primaries is inferred. The charge ratio suggests a dominantly light composition of cosmic ray primaries with energies in the energy range between 103 and 105 GeV.

  4. Vertical and Horizontal Integration of Laboratory Curricula and Course Projects across the Electronic Engineering Technology Program

    Science.gov (United States)

    Zhan, Wei; Goulart, Ana; Morgan, Joseph A.; Porter, Jay R.

    2011-01-01

    This paper discusses the details of the curricular development effort with a focus on the vertical and horizontal integration of laboratory curricula and course projects within the Electronic Engineering Technology (EET) program at Texas A&M University. Both software and hardware aspects are addressed. A common set of software tools are…

  5. Surface-conduction electron-emitter characteristics and fabrication based on vertically aligned carbon nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Shih, Yi-Ting [Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, No. 43, Section 4, Keelung Road, Taipei 10607, Taiwan (China); Li, Kuan-Wei [Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, No. 43, Section 4, Keelung Road, Taipei 10607, Taiwan (China); Honda, Shin-ichi [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Lin, Pao-Hung; Huang, Ying-Sheng [Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, No. 43, Section 4, Keelung Road, Taipei 10607, Taiwan (China); Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, No. 43, Section 4, Keelung Road, Taipei 10607, Taiwan (China); Lee, Kuei-Yi, E-mail: kylee@mail.ntust.edu.tw [Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, No. 43, Section 4, Keelung Road, Taipei 10607, Taiwan (China); Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, No. 43, Section 4, Keelung Road, Taipei 10607, Taiwan (China)

    2017-06-01

    Graphical abstract: The pattern design provides a new structure of surface-conduction electron-emitter display (SED). Delta-star shaped vertically aligned CNT (VACNT) arrays with 20o tips can simultaneously provide three emitters to bombard the sides of equilateral triangles pattern of VACNT, which produces numerous secondary electrons and enhance the SED efficiency. - Highlights: • The carbon nanotube (CNT) has replaced palladium oxide (PdO) as the electrode material for surface-conduction electron-emitter (SCE) applications. • The vertically aligned CNT (VACNT) arrays with 20° tips of the delta-star arrangement are used as cathodes that easily emit electrons. The cathode pattern simultaneously provides three emitters to bombard the sides of equilateral triangles pattern of VACNT. • The VACNT arrays were covered with magnesium oxide (MgO) nanostructures to promote the surface-conduction electron-emitter display (SED) efficiency (η). • The η was stably maintained in the 75–85% range. The proposed design provides a facile new method for developing SED applications. - Abstract: The carbon nanotube (CNT) has replaced palladium oxide (PdO) as the electrode material for surface-conduction electron-emitter (SCE) applications. Vertically aligned CNT arrays with a delta-star arrangement were patterned and synthesized onto a quartz substrate using photolithography and thermal chemical vapor deposition. Delta-star shaped VACNT arrays with 20° tips are used as cathodes that easily emit electrons because of their high electrical field gradient. In order to improve the field emission and secondary electrons (SEs) in SCE applications, magnesium oxide (MgO) nanostructures were coated onto the VACNT arrays to promote the surface-conduction electron-emitter display (SED) efficiency (η). According to the definition of η in SCE applications, in this study, the η was stably maintained in the 75–85% range. The proposed design provides a facile new method for

  6. Electronic Raman scattering and the renormalization of the electron spectrum in LuB{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Ponosov, Yu. S., E-mail: ponosov@imp.uran.ru; Streltsov, S. V., E-mail: streltsov@gmail.com [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation); Levchenko, A. V.; Filippov, V. B. [National Academy of Sciences of Ukraine, Frantsevich Institute of Materials Science Problems (Ukraine)

    2016-09-15

    The electronic Raman scattering in LuB{sub 12} single crystals of various isotope compositions is studied in the temperature range 10–650 K. The shape and the energy position of spectral maxima depend on the direction and magnitude of a probe wavevector, the temperature, and the excitation symmetry and remain unchanged when the isotope composition changes. Experimental spectra are compared with the spectra simulated on the basis of a calculated electronic structure. The experimental results are successfully described when the electron spectrum renormalization effects caused by electron–phonon coupling are taken into account. This confirms that the origin of the observed spectra in LuB{sub 12} is due to Raman scattering by electrons. A comparison of the calculated and experimental data makes it possible to determine the coupling constant (λ{sub ep} = 0.32) that gives the correct superconducting transition temperature.

  7. Vertical instability with transient characteristics in KEK-Photon Factory electron storage ring

    Directory of Open Access Journals (Sweden)

    A. Mochihashi

    2001-02-01

    Full Text Available A vertical instability of the KEK-Photon Factory electron storage ring was observed in a multibunch mode with empty buckets (bunch gap using a bunch-by-bunch beam diagnostic system that consisted of a high-speed light shutter and an optical betatron oscillation detector. It was clearly seen that vertical betatron frequencies of individual bunches varied along a bunch train. The dependence of the betatron frequencies on the bunch positions in the train was explained by modulation of trapped-ion density caused by passage of the beam. Agreement between experimental results and the theoretical prediction was quite good.

  8. On the spectrum of secondary electrons emitted during nuclear $\\beta^{-}$-decay in few-electron atoms

    CERN Document Server

    Frolov, Alexei M

    2015-01-01

    Ionization of light atoms and ions during nuclear $\\beta^{-}$-decay is considered. We determine the velocity/momentum spectrum of secondary electrons emitted during nuclear $\\beta^{-}$-decay in one-electron tritium atom. The same method can be applied to describe velocity/momentum distributions of secondary electrons emitted from $\\beta^{-}$-decaying few-electron atoms and molecules.

  9. Surface-conduction electron-emitter characteristics and fabrication based on vertically aligned carbon nanotube arrays

    Science.gov (United States)

    Shih, Yi-Ting; Li, Kuan-Wei; Honda, Shin-ichi; Lin, Pao-Hung; Huang, Ying-Sheng; Lee, Kuei-Yi

    2017-06-01

    The carbon nanotube (CNT) has replaced palladium oxide (PdO) as the electrode material for surface-conduction electron-emitter (SCE) applications. Vertically aligned CNT arrays with a delta-star arrangement were patterned and synthesized onto a quartz substrate using photolithography and thermal chemical vapor deposition. Delta-star shaped VACNT arrays with 20° tips are used as cathodes that easily emit electrons because of their high electrical field gradient. In order to improve the field emission and secondary electrons (SEs) in SCE applications, magnesium oxide (MgO) nanostructures were coated onto the VACNT arrays to promote the surface-conduction electron-emitter display (SED) efficiency (η). According to the definition of η in SCE applications, in this study, the η was stably maintained in the 75-85% range. The proposed design provides a facile new method for developing SED applications.

  10. Pedestrian induced vertical vibrations: Response to running using the Response Spectrum Method

    DEFF Research Database (Denmark)

    Matteoni, Giulia; Georgakis, Christos

    2010-01-01

    Footbridges are increasingly prone to vibrations and designers are generally unable to predict pedestrian-induced vertical vibrations. Many aspects of human loading are infact not properly taken into account for in the load models employed by the international codes of practice, such as the rando...... into account variations in the structural characteristics, crowd morphology and return period. The correction factors, together with the reference acceleration, are used to determine the final response of the footbridge, for a given probability of load occurrence.......Footbridges are increasingly prone to vibrations and designers are generally unable to predict pedestrian-induced vertical vibrations. Many aspects of human loading are infact not properly taken into account for in the load models employed by the international codes of practice......, such as the randomness of crowds travelling across the footbridge. Moreover, the codes, for most of the part, do not deal with pedestrian loading other than walking, even though running and jumping can often produce larger loads and vibration amplitudes. In this paper, an investigation inot the response of footbridges...

  11. Simultaneous measurement of lateral and vertical size of nanoparticles using transmission scanning electron microscopy (TSEM)

    Science.gov (United States)

    Buhr, E.; Bug, M. U.; Bergmann, D.; Cizmar, P.; Frase, C. G.

    2017-03-01

    A scanning electron microscope operated in transmission mode (TSEM) enables both the measurement of the lateral and vertical size (thickness) of nanoparticles. The lateral size is measured with a previously described technique where the particle boundary is determined in the TSEM image. Particle thickness is deduced from the TSEM signal level measured at the centre of the particle, which requires prior knowledge of the expected TSEM signal level. We applied different and well-known Monte-Carlo based simulation tools (Geant4 and MCSEM) to describe the electron diffusion in solid states and to calculate the expected TSEM signals taking into account particle and instrument properties. The simulation results of the different simulation models differ slightly revealing current limits of small-angle and low-energy electron scattering modelling in solid states. Nonetheless, the method allows one to correlate lateral and vertical particle thickness and thus to obtain additional information about the 3D morphology of nanoparticles. We demonstrate the method for silica particles with sizes in the range of about 10 nm-100 nm.

  12. Amplitude/phase modulation and spectrum of the vertical-cavity surface-emitting laser output

    Science.gov (United States)

    Vas'kovskaya, M. I.; Vasil'ev, V. V.; Zibrov, S. A.; Velichansky, V. L.; Akimova, I. V.; Bogatov, A. P.; Drakin, A. E.

    2017-09-01

    A new approach has been proposed for analysing the dynamics of the laser field amplitude on the basis of Maxwell's equations. This approach has been used to develop a theory for calculating modulation characteristics of vertical-cavity surface-emitting lasers in the small modulation limit. The present analysis allows one to sequentially examine the dynamics of the amplitude and phase of the electromagnetic field of light in the framework of a single physical model, proceeding from fundamental principles. The proposed approach offers a natural and unique procedure for finding all laser cavity parameters necessary for calculation. An analytical calculation in the 'small'-signal approximation has ensured good agreement with experimental data.

  13. Electron States and Quasienergy Spectrum of the Graphene Exposed to the Electromagnetic Wave

    OpenAIRE

    S.V. Kryuchkov; E.I. Kukhar’; O.S. Nikitina

    2013-01-01

    The effective spectrum and wave functions of electron states in graphene under the electromagnetic wave with circular polarization are found. The band gap in the graphene spectrum induced by the electromagnetic wave is calculated. Occurrence of such gap is shown to have the nature of the parametric resonance. The effective energy of the electron state in graphene is proved to be the energy averaged over the period of the electromagnetic wave.

  14. Band electron spectrum and thermodynamic properties of the pseudospin-electron model with tunneling splitting of levels

    Directory of Open Access Journals (Sweden)

    O.Ya.Farenyuk

    2006-01-01

    Full Text Available The pseudospin-electron model with tunneling splitting of levels is considered. Generalization of dynamic mean-field method for systems with correlated hopping was applied to the investigation of the model. Electron spectra, electron concentrations, average values of pseudospins and grand canonical potential were calculated within the alloy-analogy approximation. Electron spectrum and dependencies of the electron concentrations on chemical potential were obtained. It was shown that in the alloy-analogy approximation, the model possesses the first order phase transition to ferromagnetic state with the change of chemical potential and the second order phase transition with the change of temperature.

  15. Energy Dependence of Near-relativistic Electron Spectrum at ...

    Indian Academy of Sciences (India)

    discussed the radiation belt electron drop outs with respect to their local time, radial and particle-energy dependence. In this paper we present the energy dependence of REDs and REEs at geostationary orbit for electrons at energies 2 MeV, 0.9 MeV, 0.6 MeV with respect to the solar wind and Interplanetary Magnetic Field ...

  16. Methodology and consistency of slant and vertical assessments for ionospheric electron content models

    Science.gov (United States)

    Hernández-Pajares, Manuel; Roma-Dollase, David; Krankowski, Andrzej; García-Rigo, Alberto; Orús-Pérez, Raül

    2017-12-01

    A summary of the main concepts on global ionospheric map(s) [hereinafter GIM(s)] of vertical total electron content (VTEC), with special emphasis on their assessment, is presented in this paper. It is based on the experience accumulated during almost two decades of collaborative work in the context of the international global navigation satellite systems (GNSS) service (IGS) ionosphere working group. A representative comparison of the two main assessments of ionospheric electron content models (VTEC-altimeter and difference of Slant TEC, based on independent global positioning system data GPS, dSTEC-GPS) is performed. It is based on 26 GPS receivers worldwide distributed and mostly placed on islands, from the last quarter of 2010 to the end of 2016. The consistency between dSTEC-GPS and VTEC-altimeter assessments for one of the most accurate IGS GIMs (the tomographic-kriging GIM `UQRG' computed by UPC) is shown. Typical error RMS values of 2 TECU for VTEC-altimeter and 0.5 TECU for dSTEC-GPS assessments are found. And, as expected by following a simple random model, there is a significant correlation between both RMS and specially relative errors, mainly evident when large enough number of observations per pass is considered. The authors expect that this manuscript will be useful for new analysis contributor centres and in general for the scientific and technical community interested in simple and truly external ways of validating electron content models of the ionosphere.

  17. Vertical and longitudinal electron density structures of equatorial E- and F-regions

    Directory of Open Access Journals (Sweden)

    P. S. Brahmanandam

    2011-01-01

    Full Text Available From global soundings of ionospheric electron density made with FORMOSAT 3/COSMIC satellites for September 2006–August 2009, day-night variations in vertical and longitudinal structures of the electron densities in equatorial E- and F-regions for different seasons are investigated for the first time. The results reveal that the wavenumber-3 and wavenumber-4 patterns dominated the nighttime (22:00–04:00 LT F-region longitudinal structures in solstice and in equinox seasons, respectively. In daytime (08:00–18:00 LT F-region, the wavenumber-4 patterns governed the longitudinal structures in the September equinox and December solstice, and wavenumber-3 in March equinox and June solstice respectively. A comparison of the daytime and nighttime longitudinal electron density structures indicates that they are approximately 180° out of phase with each other. It is believed that this out of phase relation is very likely the result of the opposite phase relation between daytime and nighttime nonmigrating diurnal tidal winds that modulate background E-region dynamo electric field at different places, leading to the day-night change in the locations of the equatorial plasma fountains that are responsible for the formation of the F-region longitudinal structures. Further, a good consistency between the locations of the density structures in the same seasons of the different years for both daytime and nighttime epochs has been noticed indicating that the source mechanism for these structures could be the same.

  18. Methodology and consistency of slant and vertical assessments for ionospheric electron content models

    Science.gov (United States)

    Hernández-Pajares, Manuel; Roma-Dollase, David; Krankowski, Andrzej; García-Rigo, Alberto; Orús-Pérez, Raül

    2017-05-01

    A summary of the main concepts on global ionospheric map(s) [hereinafter GIM(s)] of vertical total electron content (VTEC), with special emphasis on their assessment, is presented in this paper. It is based on the experience accumulated during almost two decades of collaborative work in the context of the international global navigation satellite systems (GNSS) service (IGS) ionosphere working group. A representative comparison of the two main assessments of ionospheric electron content models (VTEC-altimeter and difference of Slant TEC, based on independent global positioning system data GPS, dSTEC-GPS) is performed. It is based on 26 GPS receivers worldwide distributed and mostly placed on islands, from the last quarter of 2010 to the end of 2016. The consistency between dSTEC-GPS and VTEC-altimeter assessments for one of the most accurate IGS GIMs (the tomographic-kriging GIM `UQRG' computed by UPC) is shown. Typical error RMS values of 2 TECU for VTEC-altimeter and 0.5 TECU for dSTEC-GPS assessments are found. And, as expected by following a simple random model, there is a significant correlation between both RMS and specially relative errors, mainly evident when large enough number of observations per pass is considered. The authors expect that this manuscript will be useful for new analysis contributor centres and in general for the scientific and technical community interested in simple and truly external ways of validating electron content models of the ionosphere.

  19. Plugged In: Electronics Use in Youth and Young Adults with Autism Spectrum Disorder

    Science.gov (United States)

    MacMullin, Jennifer A.; Lunsky, Yona; Weiss, Jonathan A.

    2016-01-01

    Although electronic technology currently plays an integral role for most youth, there are growing concerns of its excessive and compulsive use. This study documents patterns and impact of electronics use in individuals with autism spectrum disorder compared to typically developing peers. Participants included 172 parents of typically developing…

  20. Spectrum

    DEFF Research Database (Denmark)

    Høgfeldt Hansen, Leif

    2016-01-01

    The publication functions as a proces description of the development and construction of an urban furniture SPECTRUM in the city of Gwangju, Republic of Korea. It is used as the cataloque for the exhibition of Spectrum.......The publication functions as a proces description of the development and construction of an urban furniture SPECTRUM in the city of Gwangju, Republic of Korea. It is used as the cataloque for the exhibition of Spectrum....

  1. Energy Dependence of Near-relativistic Electron Spectrum at ...

    Indian Academy of Sciences (India)

    This may give us some insight into how we can safeguard geostationary satellites from functional anomalies of the deep dielectric charging type, which are caused by charge accumulation and subsequent discharge of relativistic electrons. In this study we examine whether there is any energy dependence in relativistic ...

  2. Electron backscatter diffraction analysis of a CZT growth tip from a vertical gradient freeze furnace

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, S. K.; Henager, C. H.; Edwards, D. J.; Schemer-Kohrn, A. L.; Bliss, M.; Riley, B. R.

    2011-08-15

    Electron backscatter diffraction (EBSD) was used to characterize the growth-tip region of a 4.2-cm diameter CdZnTe (CZT) boule grown using low-pressure Bridgman method in a vertical gradient freeze furnace. The boule was sectioned and polished and a section taken along the boule longitudinal centerline with an approximate surface area of 1-cm2 was used for optical and scanning electron microscopy. A collage was assembled using EBSD/SEM images to show morphological features, e.g., twin structure, grain structure, and overall crystal growth direction. Severely twinned regions originating from the tip and side walls were observed. The overall growth orientation was close to (1 1 0) and (1 1 2) directions. In some regions, the (0 0 1) poles of the CZT matrix aligned with the growth direction, while twins aligned such that (1 1 1) and (1 1 2) poles aligned with the growth direction. Finally, in some other areas, (1 1 2) or (0 1 1) poles of the CZT matrix aligned with the growth direction. New relationships between the CZT matrix and large Te polycrystalline particles were revealed: {1 1 2-}CZTΙΙ{1 1- 0 0}Te and {0 0 1}CZTII{0 1-1-1}Te.

  3. Calculating the electron temperature in the lightning channel by continuous spectrum

    Science.gov (United States)

    Xiangcheng, DONG; Jianhong, CHEN; Xiufang, WEI; Ping, YUAN

    2017-12-01

    Based on the theory of plasma continuous radiation, the relationship between the emission intensity of bremsstrahlung and recombination radiation and the plasma electron temperature is obtained. During the development process of a return stroke of ground flash, the intensity of continuous radiation spectrum is separated on the basis of the spectrums with obviously different luminous intensity at two moments. The electron temperature of the lightning discharge channel is obtained through the curve fitting of the continuous spectrum intensity. It is found that electron temperature increases with the increase of wavelength and begins to reduce after the peak. The peak temperature of the two spectra is close to 25 000 K. To be compared with the result of discrete spectrum, the electron temperature is fitted by the O I line and N II line of the spectrum respectively. The comparison shows that the high temperature value is in good agreement with the temperature of the lightning core current channel obtained from the ion line information, and the low temperature at the high band closes to the calculation result of the atomic line, at a low band is lower than the calculation of the atomic line, which reflects the temperature of the luminous channel of the outer corona.

  4. Ab initio calculation of the electronic absorption spectrum of liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Martiniano, Hugo F. M. C.; Galamba, Nuno [Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa (Portugal); Cabral, Benedito J. Costa, E-mail: ben@cii.fc.ul.pt [Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa (Portugal); Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Instituto de Física da Universidade de São Paulo, CP 66318, 05314-970 São Paulo, SP (Brazil)

    2014-04-28

    The electronic absorption spectrum of liquid water was investigated by coupling a one-body energy decomposition scheme to configurations generated by classical and Born-Oppenheimer Molecular Dynamics (BOMD). A Frenkel exciton Hamiltonian formalism was adopted and the excitation energies in the liquid phase were calculated with the equation of motion coupled cluster with single and double excitations method. Molecular dynamics configurations were generated by different approaches. Classical MD were carried out with the TIP4P-Ew and AMOEBA force fields. The BLYP and BLYP-D3 exchange-correlation functionals were used in BOMD. Theoretical and experimental results for the electronic absorption spectrum of liquid water are in good agreement. Emphasis is placed on the relationship between the structure of liquid water predicted by the different models and the electronic absorption spectrum. The theoretical gas to liquid phase blue-shift of the peak positions of the electronic absorption spectrum is in good agreement with experiment. The overall shift is determined by a competition between the O–H stretching of the water monomer in liquid water that leads to a red-shift and polarization effects that induce a blue-shift. The results illustrate the importance of coupling many-body energy decomposition schemes to molecular dynamics configurations to carry out ab initio calculations of the electronic properties in liquid phase.

  5. Time-resolved electron spectrum diagnostics for a free-electron laser

    NARCIS (Netherlands)

    Gillespie, W. A.; MacLeod, A. M.; Martin, P. F.; van der Meer, A. F. G.; van Amersfoort, P. W.

    1996-01-01

    Time-resolved electron-beam diagnostics have been developed for use with free-electron lasers (FELs) and associated electron sources, based on the techniques of secondary electron emission and optical transition radiation (OTR). The 32-channel OTR detector forms part of a high-resolution (0.18%)

  6. The KLM + KLN Auger electron spectrum of rubidium in different matrices

    Science.gov (United States)

    Inoyatov, A. Kh; Kovalík, A.; Perevoshchikov, L. L.; Filosofov, D. V.; Vénos, D.; Lee, B. Q.; Ekman, J.; Baimukhanova, A.

    2017-08-01

    The KLM + KLN Auger electron spectrum of rubidium (Z = 37) emitted in the electron capture decay of radioactive 83Sr in a polycrystalline platinum matrix and also 85Sr in polycrystalline platinum and carbon matrices as well as in an evaporated layer onto a carbon backing were experimentally studied in detail for the first time using a combined electrostatic electron spectrometer. Energies, relative intensities, and natural widths of fifteen basic spectrum components were determined and compared with both theoretical predictions and experimental data for krypton (Z = 36). Relative spectrum line energies obtained from the semi-empirical calculations in intermediate coupling scheme were found to agree within 3σ with the measured values while disagreement with experiment exceeding 3σ was often observed for values obtained from our multiconfiguration Dirac-Hartree-Fock calculations. The absolute energy of the dominant spectrum component given by the semi-empirical approach agrees within 1σ with the measured value. Shifts of +(0.2 ± 0.2) and -(1.9 ± 0.2) eV were measured for the dominant KLM spectrum components between the 85Sr sources prepared by vacuum evaporation on and implanted into the carbon foil, respectively, relative to 85Sr implanted into the platinum foil. A value of (713 ± 2) eV was determined for the energy difference of the dominant components of the KLM + KLN Auger electron spectra of rubidium and krypton generated in the polycrystalline platinum matrix. From the detailed analysis of the measured data and available theoretical results, the general conclusion can be drawn that the proper description of the KLM + KLN Auger electron spectrum for Z around 37 should still be based on the intermediate coupling of angular momenta taking into account relativistic effects.

  7. Vertical marginal discrepancies of metal castings obtained using different pattern materials: A scanning electron microscope study

    Directory of Open Access Journals (Sweden)

    R Sushma

    2014-01-01

    Full Text Available Background and Objectives: Dental Casting involves various stages of processing, out of which any may affect the dimensional accuracy. The fit of a casting depends not only on the method of fabrication employed but also on the type of materials utilized. One important variable in the casting process is the type of pattern material employed. This study was carried out to determine and compare the effect of different pattern materials on the vertical marginal accuracy of complete cast crowns. Materials and Methods: A standardized metal master die simulating a prepared crown was used to prepare 60 models on which patterns were fabricated using Inlay Pattern Wax; Auto-polymerized Pattern Resin and Light Cured Modeling Resin and cast immediately. Castings of the patterns were subjected to analysis of marginal fit using a scanning electron microscope (SEM. Results: One-way ANOVA result showed a significant difference in the gap observed between the castings fabricated using the three types of pattern materials (P 0.05. Conclusion: With strict adherence to the principles of pattern fabrication and immediate casting, Inlay wax can still be the pattern material of choice to produce a casting with minimal marginal discrepancy with added advantages of being user friendly and cost effective.

  8. Calculation of the spectrum of quasiparticle electron excitations in organic molecular semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Tikhonov, E. V., E-mail: tikhonov@mig.phys.msu.ru [Moscow State University (Russian Federation); Uspenskii, Yu. A. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Khokhlov, D. R. [Moscow State University (Russian Federation)

    2015-06-15

    A quasiparticle electronic spectrum belongs to the characteristics of nanoobjects that are most important for applications. The following methods of calculating the electronic spectrum are analyzed: the Kohn-Sham equations of the density functional theory (DFT), the hybrid functional method, the GW approximation, and the Lehmann approximation used in the spectral representation of one-electron Green’s function. The results of these approaches are compared with the data of photoemission measurements of benzene, PTCDA, and phthalocyanine (CuPc, H{sub 2}Pc, FePc, PtPc) molecules, which are typical representatives of organic molecular semiconductors (OMS). This comparison demonstrates that the Kohn-Sham equations of DFT incorrectly reproduce the electronic spectrum of OMS. The hybrid functional method correctly describes the spectrum of the valence and conduction bands; however, the HOMO-LUMO gap width is significantly underestimated. The correct gap width is obtained in both the GW approximation and the Lehmann approach, and the total energy in this approach can be calculated in the local density approximation of DFT.

  9. Validation of Autism Spectrum Disorder Diagnoses in Large Healthcare Systems with Electronic Medical Records

    Science.gov (United States)

    Coleman, Karen J.; Lutsky, Marta A.; Yau, Vincent; Qian, Yinge; Pomichowski, Magdalena E.; Crawford, Phillip M.; Lynch, Frances L.; Madden, Jeanne M.; Owen-Smith, Ashli; Pearson, John A.; Pearson, Kathryn A.; Rusinak, Donna; Quinn, Virginia P.; Croen, Lisa A.

    2015-01-01

    To identify factors associated with valid Autism Spectrum Disorder (ASD) diagnoses from electronic sources in large healthcare systems. We examined 1,272 charts from ASD diagnosed youth <18 years old. Expert reviewers classified diagnoses as confirmed, probable, possible, ruled out, or not enough information. A total of 845 were classified with…

  10. Variability of the Magnetic Field Power Spectrum in the Solar Wind at Electron Scales

    Science.gov (United States)

    Roberts, Owen Wyn; Alexandrova, O.; Kajdič, P.; Turc, L.; Perrone, D.; Escoubet, C. P.; Walsh, A.

    2017-12-01

    At electron scales, the power spectrum of solar-wind magnetic fluctuations can be highly variable and the dissipation mechanisms of the magnetic energy into the various particle species is under debate. In this paper, we investigate data from the Cluster mission’s STAFF Search Coil magnetometer when the level of turbulence is sufficiently high that the morphology of the power spectrum at electron scales can be investigated. The Cluster spacecraft sample a disturbed interval of plasma where two streams of solar wind interact. Meanwhile, several discontinuities (coherent structures) are seen in the large-scale magnetic field, while at small scales several intermittent bursts of wave activity (whistler waves) are present. Several different morphologies of the power spectrum can be identified: (1) two power laws separated by a break, (2) an exponential cutoff near the Taylor shifted electron scales, and (3) strong spectral knees at the Taylor shifted electron scales. These different morphologies are investigated by using wavelet coherence, showing that, in this interval, a clear break and strong spectral knees are features that are associated with sporadic quasi parallel propagating whistler waves, even for short times. On the other hand, when no signatures of whistler waves at ∼ 0.1{--}0.2{f}{ce} are present, a clear break is difficult to find and the spectrum is often more characteristic of a power law with an exponential cutoff.

  11. Corrections to the density-functional theory electronic spectrum: Copper phthalocyanine

    DEFF Research Database (Denmark)

    Vazquez, Hector; Jelinek, P.; Brandbyge, Mads

    2009-01-01

    A method for improving the electronic spectrum of standard Density-Functional Theory (DFT) calculations (i.e., LDA or GGA approximations) is presented, and its application is discussed for the case of the copper phthalocyanine (CuPc) molecule. The method is based on a treatment of exchange...

  12. Energy Spectrum of Cosmic-Ray Electron and Positron from 10 GeV to 3 TeV Observed with the Calorimetric Electron Telescope on the International Space Station

    Science.gov (United States)

    Adriani, O.; Akaike, Y.; Asano, K.; Asaoka, Y.; Bagliesi, M. G.; Bigongiari, G.; Binns, W. R.; Bonechi, S.; Bongi, M.; Brogi, P.; Buckley, J. H.; Cannady, N.; Castellini, G.; Checchia, C.; Cherry, M. L.; Collazuol, G.; di Felice, V.; Ebisawa, K.; Fuke, H.; Guzik, T. G.; Hams, T.; Hareyama, M.; Hasebe, N.; Hibino, K.; Ichimura, M.; Ioka, K.; Ishizaki, W.; Israel, M. H.; Javaid, A.; Kasahara, K.; Kataoka, J.; Kataoka, R.; Katayose, Y.; Kato, C.; Kawanaka, N.; Kawakubo, Y.; Krawczynski, H. S.; Krizmanic, J. F.; Kuramata, S.; Lomtadze, T.; Maestro, P.; Marrocchesi, P. S.; Messineo, A. M.; Mitchell, J. W.; Miyake, S.; Mizutani, K.; Moiseev, A. A.; Mori, K.; Mori, M.; Mori, N.; Motz, H. M.; Munakata, K.; Murakami, H.; Nakahira, S.; Nishimura, J.; de Nolfo, G. A.; Okuno, S.; Ormes, J. F.; Ozawa, S.; Pacini, L.; Palma, F.; Papini, P.; Penacchioni, A. V.; Rauch, B. F.; Ricciarini, S. B.; Sakai, K.; Sakamoto, T.; Sasaki, M.; Shimizu, Y.; Shiomi, A.; Sparvoli, R.; Spillantini, P.; Stolzi, F.; Takahashi, I.; Takayanagi, M.; Takita, M.; Tamura, T.; Tateyama, N.; Terasawa, T.; Tomida, H.; Torii, S.; Tsunesada, Y.; Uchihori, Y.; Ueno, S.; Vannuccini, E.; Wefel, J. P.; Yamaoka, K.; Yanagita, S.; Yoshida, A.; Yoshida, K.; Yuda, T.; Calet Collaboration

    2017-11-01

    First results of a cosmic-ray electron and positron spectrum from 10 GeV to 3 TeV is presented based upon observations with the CALET instrument on the International Space Station starting in October, 2015. Nearly a half million electron and positron events are included in the analysis. CALET is an all-calorimetric instrument with total vertical thickness of 30 X0 and a fine imaging capability designed to achieve a large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum over 30 GeV can be fit with a single power law with a spectral index of -3.152 ±0.016 (stat+syst ). Possible structure observed above 100 GeV requires further investigation with increased statistics and refined data analysis.

  13. Energy Spectrum of Cosmic-Ray Electron and Positron from 10 GeV to 3 TeV Observed with the Calorimetric Electron Telescope on the International Space Station.

    Science.gov (United States)

    Adriani, O; Akaike, Y; Asano, K; Asaoka, Y; Bagliesi, M G; Bigongiari, G; Binns, W R; Bonechi, S; Bongi, M; Brogi, P; Buckley, J H; Cannady, N; Castellini, G; Checchia, C; Cherry, M L; Collazuol, G; Di Felice, V; Ebisawa, K; Fuke, H; Guzik, T G; Hams, T; Hareyama, M; Hasebe, N; Hibino, K; Ichimura, M; Ioka, K; Ishizaki, W; Israel, M H; Javaid, A; Kasahara, K; Kataoka, J; Kataoka, R; Katayose, Y; Kato, C; Kawanaka, N; Kawakubo, Y; Krawczynski, H S; Krizmanic, J F; Kuramata, S; Lomtadze, T; Maestro, P; Marrocchesi, P S; Messineo, A M; Mitchell, J W; Miyake, S; Mizutani, K; Moiseev, A A; Mori, K; Mori, M; Mori, N; Motz, H M; Munakata, K; Murakami, H; Nakahira, S; Nishimura, J; de Nolfo, G A; Okuno, S; Ormes, J F; Ozawa, S; Pacini, L; Palma, F; Papini, P; Penacchioni, A V; Rauch, B F; Ricciarini, S B; Sakai, K; Sakamoto, T; Sasaki, M; Shimizu, Y; Shiomi, A; Sparvoli, R; Spillantini, P; Stolzi, F; Takahashi, I; Takayanagi, M; Takita, M; Tamura, T; Tateyama, N; Terasawa, T; Tomida, H; Torii, S; Tsunesada, Y; Uchihori, Y; Ueno, S; Vannuccini, E; Wefel, J P; Yamaoka, K; Yanagita, S; Yoshida, A; Yoshida, K; Yuda, T

    2017-11-03

    First results of a cosmic-ray electron and positron spectrum from 10 GeV to 3 TeV is presented based upon observations with the CALET instrument on the International Space Station starting in October, 2015. Nearly a half million electron and positron events are included in the analysis. CALET is an all-calorimetric instrument with total vertical thickness of 30 X_{0} and a fine imaging capability designed to achieve a large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum over 30 GeV can be fit with a single power law with a spectral index of -3.152±0.016 (stat+syst). Possible structure observed above 100 GeV requires further investigation with increased statistics and refined data analysis.

  14. Effect of magnetic field on electron spectrum in spherical nano-structures

    Directory of Open Access Journals (Sweden)

    V. Holovatsky

    2014-03-01

    Full Text Available The influence of the magnetic field on energy spectrum and wave functions of electron in spherical nano-structures such as single quantum dot and spherical layer is investigated. It is shown that the magnetic field takes off the spectrum degeneration with respect to the magnetic quantum number. Increasing magnetic field induction entails the monotonous character of electron energy for the states with m ≥ 0 and non-monotonous one for the states with m < 0. The electron wave functions of the ground and few excited states are studied considering the influence of the magnetic field. It is shown that 1s and 1p states are degenerated in the spherical layer driven by the strong magnetic field. In the limit case, the series of size-quantized levels produce the Landau levels which are typical for the bulk crystals.

  15. Decomposition study of the electron paramagnetic resonance spectrum of irradiated alanine.

    Science.gov (United States)

    Vanhaelewyn, G C; Amira, S A; Mondelaers, W K; Callens, F J

    2000-02-01

    Recent Electron Paramagnetic Resonance (EPR) studies on alanine powders as a function of irradiation dose and temperature on the one hand and single crystal Electron Nuclear DOuble Resonance (ENDOR) studies on the other hand, showed the presence of at least three radicals contributing to the total alanine EPR spectrum. The latter spectrum obtained after irradiation at room temperature (RT), is dominated by the well-known stable-alanine-radical (SAR) CH3C*HCOO-, also denoted R1. Appropriate heating of irradiated alanine causes the relative contribution of R1 to decrease, resulting in a spectrum mainly caused by the H-abstraction radical CH3C*(NH3)COO-, denoted R2. Although the EPR spectrum of these two radicals could be satisfactorily simulated, their influence on dose reconstruction has not been reported yet. Therefore, a detailed Maximum Likelihood Common Factor Analysis (MLCFA) study has been performed on EPR spectra from polycrystalline alanine samples, after irradiation and heat treatments. Conclusions concerning the number of contributing radicals and their influence on the RT irradiated alanine EPR spectrum will be made.

  16. Validation of a method for ionospheric electron density reconstruction by means of vertical incidence data during quiet and storm periods

    Directory of Open Access Journals (Sweden)

    P. Coïsson

    2005-06-01

    Full Text Available A preliminary validation of the technique developed using the NeQuick ionospheric model and the «effective ionization parameter» Az, based on vertical total electron content data ingestion, was carried out in a previous study. The current study was performed to extend the analyzed conditions and confirm the results. The method to validate this technique is based on a comparison between hourly F2 peak values measured with Vertical Incidence (VI soundings and those calculated with the new technique. Data corresponding to different hours and seasons (equinox, summer solstice, and winter solstice during the period 2000-2003 (high and medium solar activity conditions were compared for all available ionosonde stations. The results show a good agreement between foF2 and hmF2 values obtained with the new technique and measurements from vertical incidence soundings during quiet and storms conditions.

  17. Streak Camera Studies of Vertical Synchro-Betatron-Coupled Electron Beam Motion in the APS Storage Ring

    CERN Document Server

    Yang Bing Xin; Guo, Weiming; Harkay, Katherine C; Sajaev, Vadim

    2005-01-01

    We present experimental studies of synchro-betatron-coupled electron beam motion in the Advanced Photon Source storage ring. We used a vertical kicker to start the beam motion. When the vertical chromaticity is nonzero, electrons with different initial synchrotron phases have slightly different betatron frequencies from the synchronous particle, resulting in a dramatic progression of bunch-shape distortion. Depending on the chromaticity and the time following the kick, images ranging from a simple vertical tilt in the bunch to more complicated twists and bends are seen with a visible light streak camera. Turn-by-turn beam position monitor data were taken as well. We found that the experimental observations are well described by the synchro-betatron-coupled equations of motion. We are investigating the potential of using the tilted bunch to generate picosecond x-ray pulses. Also note that the fast increase in vertical beam size after the kick is dominated by the internal synchro-betatron-coupled motion of the ...

  18. Low-voltage organic electronics based on a gate-tunable injection barrier in vertical graphene-organic semiconductor heterostructures.

    Science.gov (United States)

    Hlaing, Htay; Kim, Chang-Hyun; Carta, Fabio; Nam, Chang-Yong; Barton, Rob A; Petrone, Nicholas; Hone, James; Kymissis, Ioannis

    2015-01-14

    The vertical integration of graphene with inorganic semiconductors, oxide semiconductors, and newly emerging layered materials has recently been demonstrated as a promising route toward novel electronic and optoelectronic devices. Here, we report organic thin film transistors based on vertical heterojunctions of graphene and organic semiconductors. In these thin heterostructure devices, current modulation is accomplished by tuning of the injection barriers at the semiconductor/graphene interface with the application of a gate voltage. N-channel devices fabricated with a thin layer of C60 show a room temperature on/off ratio >10(4) and current density of up to 44 mAcm(-2). Because of the ultrashort channel intrinsic to the vertical structure, the device is fully operational at a driving voltage of 200 mV. A complementary p-channel device is also investigated, and a logic inverter based on two complementary transistors is demonstrated. The vertical integration of graphene with organic semiconductors via simple, scalable, and low-temperature fabrication processes opens up new opportunities to realize flexible, transparent organic electronic, and optoelectronic devices.

  19. First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of $^{163}$Ho

    CERN Document Server

    Ranitzsch, P. C. -O.; Wegner, M.; Kempf, S.; Fleischmann, A.; Enss, C.; Gastaldo, L.; Herlert, A.; Johnston, K.

    2014-01-01

    The isotope $^{163}$Ho undergoes an electron capture process with a recommended value for the energy available to the decay, $Q_{\\rm EC}$, of about 2.5 keV. According to the present knowledge, this is the lowest $Q_{\\rm EC}$ value for electron capture processes. Because of that, $^{163}$Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the $^{163}$Dy daughter atom upon the capture of an electron from the 5s shell in $^{163}$Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the $^{163}$Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of $^{163}$Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we dis...

  20. The energy spectrum of cosmic-ray electrons measured with H.E.S.S.

    Energy Technology Data Exchange (ETDEWEB)

    Egberts, Kathrin

    2009-03-30

    The spectrum of cosmic-ray electrons has so far been measured using balloon and satellite-based instruments. At TeV energies, however, the sensitivity of such instruments is very limited due to the low flux of electrons at very high energies and small detection areas of balloon/satellite based experiments. The very large collection area of ground-based imaging atmospheric Cherenkov telescopes gives them a substantial advantage over balloon/ satellite based instruments when detecting very-high-energy electrons (> 300 GeV). By analysing data taken by the High Energy Stereoscopic System (H.E.S.S.), this work extends the known electron spectrum up to 4 TeV - a range that is not accessible to direct measurements. However, in contrast to direct measurements, imaging atmospheric Cherenkov telescopes such as H.E.S.S. detect air showers that cosmic-ray electrons initiate in the atmosphere rather than the primary particle. Thus, the main challenge is to differentiate between air showers initiated by electrons and those initiated by the hadronic background. A new analysis technique was developed that determines the background with the support of the machine-learning algorithm Random Forest. It is shown that this analysis technique can also be applied in other areas such as the analysis of diffuse {gamma} rays from the Galactic plane. (orig.)

  1. Measurement of the Electron Energy Spectrum and its Moments in Inclusive B --> X e nu Decays

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, T

    2004-04-19

    We report a measurement of the inclusive electron energy spectrum for semileptonic decays of B mesons in a data sample of 52 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. We determine the branching fraction, first, second, and third moments of the spectrum for lower cut-offs on the electron energy between 0.6 and 1.5GeV. We measure the partial branching fraction to be {Beta}(B {yields} Xev,E{sub e} > 0.6GeV) = (10.36 {+-} 0.06(stat.) {+-} 0.23(sys.))%.

  2. Theoretical studies of electronic structure, phonon spectrum and electron-phonon interaction in AlCNi{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Tuetuencue, H M [Sakarya ueniversitesi, Fen-Edebiyat Fakueltesi, Fizik Boeluemue, 54140, Adapazari (Turkey); Duman, S [Sakarya ueniversitesi, Fen-Edebiyat Fakueltesi, Fizik Boeluemue, 54140, Adapazari (Turkey); Bagci, S [Sakarya ueniversitesi, Fen-Edebiyat Fakueltesi, Fizik Boeluemue, 54140, Adapazari (Turkey); Srivastava, G P [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)

    2007-12-15

    We report results of first-principles calculations for structural properties, electronic structure, phonon spectrum and electron-phonon interaction for the antiperovskite compound AlCNi{sub 3}. The structural properties are calculated using a plane-wave-pseudopotential method and the density functional theory within the generalised gradient approximation. The electronic structure and density of states for AlCNi{sub 3} are presented and compared with previous theoretical calculations. Our structural and electronic results are used, within the implementation of a linear response technique, for calculations of phonon states. We have observed that all phonon modes are stable along the [100] direction while unstable phonon modes are found in the [110] and [111] symmetry directions. At the Brillouin zone edge point X, the electron-phonon coupling parameters for phonon modes in AlCNi{sub 3} are calculated to be smaller than their corresponding values for MgCNi{sub 3}. This result indicates that the electron-phonon interaction is not very strong in AlCNi{sub 3}.

  3. Electron spin resonance absorption spectrum of trivalent gadolinium in the oxide YAIG

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, S.A. (Argonne National Lab., IL); Marshall, T.; Serway, R.A.

    1978-01-01

    The electron spin resonance absorption spectrum of trivalent gadolinium in single crystals of yttrium-aluminium garnet is re-investigated at X-band and Q-band wavelengths. Fine structure spectral parameters deduced from Q-band wavelength measurements are found to predict satisfactorily spectral observations at both wavelengths. A list of spectral parameters deduced from data taken at 77/sup 0/K is given.

  4. Design, fabrication, and performance analysis of GaN vertical electron transistors with a buried p/n junction

    Energy Technology Data Exchange (ETDEWEB)

    Yeluri, Ramya, E-mail: ramyay@ece.ucsb.edu; Lu, Jing; Keller, Stacia; Mishra, Umesh K. [Electrical and Computer Engineering Department, University of California Santa Barbara, Santa Barbara, California 93106 (United States); Hurni, Christophe A.; Browne, David A.; Speck, James S. [Materials Department, University of California Santa Barbara, Santa Barbara, California 93106 (United States); Chowdhury, Srabanti [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States)

    2015-05-04

    The Current Aperture Vertical Electron Transistor (CAVET) combines the high conductivity of the two dimensional electron gas channel at the AlGaN/GaN heterojunction with better field distribution offered by a vertical design. In this work, CAVETs with buried, conductive p-GaN layers as the current blocking layer are reported. The p-GaN layer was regrown by metalorganic chemical vapor deposition and the subsequent channel regrowth was done by ammonia molecular beam epitaxy to maintain the p-GaN conductivity. Transistors with high ON current (10.9 kA/cm{sup 2}) and low ON-resistance (0.4 mΩ cm{sup 2}) are demonstrated. Non-planar selective area regrowth is identified as the limiting factor to transistor breakdown, using planar and non-planar n/p/n structures. Planar n/p/n structures recorded an estimated electric field of 3.1 MV/cm, while non-planar structures showed a much lower breakdown voltage. Lowering the p-GaN regrowth temperature improved breakdown in the non-planar n/p/n structure. Combining high breakdown voltage with high current will enable GaN vertical transistors with high power densities.

  5. Search for an admixture of sterile neutrino in the electron spectrum from tritium $\\beta$-decay

    CERN Document Server

    Abdurashitov, D; Likhovid, N; Lokhov, A; Tkachev, I; Yants, V

    2014-01-01

    We propose an experiment intended for search for an admixture of sterile neutrino with mass m$_s$ in the range of 1-8 keV that may be detected as specific distortion of the electron energy spectrum during tritium decay. The distortion is spread over large part of the spectrum so to reveal it one can use a detector with relatively poor (near 10-15%) energy resolution. A classic proportional counter is a simple natural choice for a tritium $\\beta$-decay detector. The method we are proposing is original in two respects. First, the counter is produced as a whole from fully-fused quartz tube allowing to measure current pulse directly from anode while providing high stability for a long time. Second, a modern digital acquisition technique can be used in measurements at ultrahigh count rate - up to 10$^6$ Hz. As a result an energy spectrum of tritium electrons containing up to 10$^{12}$ counts may be collected in a month of live time measurements. Due to high statistics an upper limit down to 10$^{-3}$..10$^{-5}$ ca...

  6. Implications of the cosmic ray electron spectrum and anisotropy measured with Fermi-LAT

    Energy Technology Data Exchange (ETDEWEB)

    Di Bernardo, Giuseppe [Gothenburg Univ. (Sweden). Dept. of Physics; Evoli, Carmelo [SISSA, Trieste (Italy); Gaggero, Daniele; Grasso, Dario [Pisa Univ. (Italy). Dipt. die Fisica; INFN, Pisa (Italy); Maccione, Luca [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Mazziotta, Mario Nicola [Istituto Nazionale di Fisica Nucleare, Bari (Italy)

    2010-11-15

    The Fermi Large Area Telescope (LAT) collaboration recently released the updated results of the measurement of the cosmic ray electron (CRE) spectrum and published its first constraints on the CRE anisotropy. With respect to the previous Fermi-LAT results, the CRE spectrum measurement was extended down from 20 to 7 GeV, thus providing a better lever arm to discriminate theoretical models. Here we show that the new data strengthen the evidence for the presence of two distinct electron and positron spectral components. Furthermore, we show that under such hypothesis most relevant CRE and positron data sets are remarkably well reproduced. Consistent fits of cosmic-ray nuclei and antiproton data, which are crucial to validate the adopted propagation setup(s) and to fix the solar modulation potential, are obtained for the Kraichnan and plain-diffusion propagation setups, while the Kolmogorov one is disfavored. We then confirm that nearby pulsars are viable source candidates of the required e{sup {+-}} extra-component. In that case, we show that the predicted CRE anisotropy is compatible with Fermi-LAT constraints and that a positive detection should be at hand of that observatory. Models assuming that only nearby supernova remnants contribute to the high energy tail of the observed CRE spectrum are in contrast with anisotropy limits. (orig.)

  7. Vertical GaN Devices for Power Electronics in Extreme Environments

    Science.gov (United States)

    2016-03-31

    A while reverse biased at 1200V. The safe zone of the single pulse avalanche current is limited by peak pulse power and energy deposited in the...Vertical GaN devices are studied under cryogenic conditions, radiation, and ruggedness performance under repetitive avalanche stress. Mg, which is used...temperatures below 200K. Impact ionization based avalanche breakdown in GaN p-n junctions is characterized between 77K and 423K for the first time

  8. Inter-Layer Coupling Effects on Vertical Electron Transport in Multilayer Graphene Nanoribbons

    Science.gov (United States)

    Hashimoto, F.; Mori, N.

    2017-10-01

    We have performed nonequilibrium Green function simulations on the vertical transport characteristics in multilayer graphene nanoribbons sandwiched between two graphene contact layers with varying the inter-layer coupling strength β. We find that the integrated transmission function thorough the top (or bottom) layer is hardly affected by β when the incident energy is close to the Dirac point. The β-insensitive energy window becomes narrower as the channel length increases.

  9. The spectrum of surface plasma polaritons under Gaussian spatial distribution of electrons

    CERN Document Server

    Dmitruk, M L; Mamontova, Y V

    2002-01-01

    Dispersion of surface electromagnetic waves (surface plasma polaritons, SPP) a nonhomogeneous solid-state plasma with Gaussian spatial distribution of electrons is calculated within the local dielectric function approximation. The calculated spatial distribution of electromagnetic fields allows one to identify the nature of the corresponding branches of the SPP dispersion. The attenuated total reflections spectrum is calculated for the Otto geometry of the experiment. The genesis of SPP dispersion curves under variation in the characteristic parameters of the solid-state plasma distribution is investigated as well.

  10. Dimensionality effect on two-electron energy spectrum: A fractional-dimension-based formulation

    Energy Technology Data Exchange (ETDEWEB)

    Correa, R.; Gutiérrez, W.; Mikhailov, I. [Escuela de Física, Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia); Fulla, M.R. [Escuela de Física, Universidad Nacional de Colombia, A.A. 3840, Medellín (Colombia); Marín, J.H., E-mail: jhmarin@unal.edu.co [Escuela de Física, Universidad Nacional de Colombia, A.A. 3840, Medellín (Colombia)

    2015-07-17

    We analyze the spectrum of two-electron quantum dot with anisotropic parabolic confinement by using the fractional-dimension formulation which allows us to reduce the two-particle problem to two equations for independent particles in an effective space with variable dimension, ranging between two and three for ellipsoidal-shaped quantum dots and between one and two for elliptical-shaped quantum disks. The dependencies of energy levels on the heterostructure sizes for quantum dots, disks and wires are presented. - Highlights: • We report the two-electron eigenenergies in a quantum dot with anisotropic parabolic confinement. • Our model is versatile enough to consider changes in the dimension space from 3 to 2 and 2 to 1. • The two-electron structure is calculated in integer and fractional dimensional spaces. • The two-electron energy structure is sensitive to the quantum dot size and morphology changes. • The electron–electron Coulomb interaction is strongly dependent on the space dimensionality.

  11. Forming of space charge wave with broad frequency spectrum in helical relativistic two-stream electron beams

    DEFF Research Database (Denmark)

    Lysenko, Alexander V.; Volk, Iurii I.; Serozhko, A.

    2017-01-01

    We elaborate a quadratic nonlinear theory of plural interactions of growing space charge wave (SCW) harmonics during the development of the two-stream instability in helical relativistic electron beams. It is found that in helical two-stream electron beams the growth rate of the two......-stream instability increases with the beam entrance angle. An SCW with the broad frequency spectrum, in which higher harmonics have higher amplitudes, forms when the frequency of the first SCW harmonic is much less than the critical frequency of the two-stream instability. For helical electron beams the spectrum...... expands with the increase of the beam entrance angle. Moreover, we obtain that utilizing helical electron beams in multiharmonic two-stream superheterodyne free-electron lasers leads to the improvement of their amplification characteristics, the frequency spectrum broadening in multiharmonic signal...

  12. Ocean Turbulence. Part 4; Mesoscale Modeling in Isopycnal Coordinates the role of the Spectrum of Vertical Shear

    Science.gov (United States)

    Canuto, V. M.; Dubovikov, M. S.

    1999-01-01

    We study the tracer subgrid term in isopycnal coordinates, S(sub I). We employ two ingredients: the experimental data on vertical spectra of ocean turbulence measured by Gargett et al.(1981) and the stochastic approach recently developed by Dukowicz and Smith (1997). Our result confirms that S(sub I) is made of two parts: an advection and a diffusion term. However, the tracer bolus velocity u** consists of two terms u** = u(sub 1) + u(sub 2) while in the GM model there is only a term related to u(sub 1) which is shown to be: u(sub 1) = k(bar-q)(sup -1)(delta)(sub rho) where bar-q is the thickness weighted average potential vorticity, a result in agreement with the recent suggestions by Treguier et al. (1997), Lee et al. (1997) and Greatbatch (1998). The second component u(sub 2) IS new. We compute it in the geostrophic approximation using the Gargett et al. data (1981) on ocean vertical turbulence. We find that u(sub 2) much greater than u(sub 1) and that u(sub 2) is orthogonal to u(sub 1).

  13. Electron-related linear and nonlinear optical responses in vertically coupled triangular quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Orozco, J.C. [Unidad Académica de Física. Universidad Autónoma de Zacatecas, Calzada Solidaridad esquina con Paseo la Bufa S/N, C.P. 98060. Zacatecas, Zac. (Mexico); Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Mora-Ramos, M.E. [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Ave. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico); Duque, C.A., E-mail: cduque@fisica.udea.edu.co [Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia)

    2014-11-01

    The conduction band states of GaAs-based vertically coupled double triangular quantum dots in two dimensions are investigated within the effective mass and parabolic approximation, using a diagonalization procedure to solve the corresponding Schrödinger-like equation. The effect of an externally applied static electric field is included in the calculation, and the variation of the lowest confined energy levels as a result of the change of the field strength is reported for different geometrical setups. The linear and nonlinear optical absorptions and the relative change of the refractive index, associated with the energy transition between the ground and the first excited state in the system, are studied as a function of the incident light frequency for distinct configurations of inter-dot distance and electric field intensities. The blueshift of the resonant absorption peaks is detected as a consequence of the increment in the field intensity, whereas the opposite effect is obtained from the increase of inter-dot vertical distance. It is also shown that for large enough values of the electric field there is a quenching of the optical absorption due to field-induced change of symmetry of the first excited state wavefunction, in the case of triangular dots of equal shape and size.

  14. Measurements of the cosmic-ray electron and positron spectrum and anisotropies with the Fermi LAT

    Science.gov (United States)

    Loparco, F.; Fermi LAT Collaboration

    2017-12-01

    The Large Area Telescope (LAT) onboard the Fermi satellite is a pair-conversion telescope for high-energy gamma rays of astrophysical origin. Although it was designed to be a high-sensitivity gamma-ray telescope, the LAT has proved to be an excellent electron/positron detector. It has been operating in low Earth orbit since June 2008 and has collected more than 16 million cosmic-ray electron and positron (CRE) events in its first seven years of operation. The huge data sample collected by the LAT enables a precise measurement of the CRE energy spectrum up to the TeV region. A search for anisotropies in the arrival directions of CREs was also performed. The upper limits on the dipole anisotropy probe the presence of nearby young and middle-aged CRE sources.

  15. Direct detection of a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons

    Science.gov (United States)

    DAMPE Collaboration; Ambrosi, G.; An, Q.; Asfandiyarov, R.; Azzarello, P.; Bernardini, P.; Bertucci, B.; Cai, M. S.; Chang, J.; Chen, D. Y.; Chen, H. F.; Chen, J. L.; Chen, W.; Cui, M. Y.; Cui, T. S.; D'Amone, A.; de Benedittis, A.; De Mitri, I.; di Santo, M.; Dong, J. N.; Dong, T. K.; Dong, Y. F.; Dong, Z. X.; Donvito, G.; Droz, D.; Duan, K. K.; Duan, J. L.; Duranti, M.; D'Urso, D.; Fan, R. R.; Fan, Y. Z.; Fang, F.; Feng, C. Q.; Feng, L.; Fusco, P.; Gallo, V.; Gan, F. J.; Gao, M.; Gao, S. S.; Gargano, F.; Garrappa, S.; Gong, K.; Gong, Y. Z.; Guo, D. Y.; Guo, J. H.; Hu, Y. M.; Huang, G. S.; Huang, Y. Y.; Ionica, M.; Jiang, D.; Jiang, W.; Jin, X.; Kong, J.; Lei, S. J.; Li, S.; Li, X.; Li, W. L.; Li, Y.; Liang, Y. F.; Liang, Y. M.; Liao, N. H.; Liu, H.; Liu, J.; Liu, S. B.; Liu, W. Q.; Liu, Y.; Loparco, F.; Ma, M.; Ma, P. X.; Ma, S. Y.; Ma, T.; Ma, X. Q.; Ma, X. Y.; Marsella, G.; Mazziotta, M. N.; Mo, D.; Niu, X. Y.; Peng, X. Y.; Peng, W. X.; Qiao, R.; Rao, J. N.; Salinas, M. M.; Shang, G. Z.; H. Shen, W.; Shen, Z. Q.; Shen, Z. T.; Song, J. X.; Su, H.; Su, M.; Sun, Z. Y.; Surdo, A.; Teng, X. J.; Tian, X. B.; Tykhonov, A.; Vagelli, V.; Vitillo, S.; Wang, C.; Wang, H.; Wang, H. Y.; Wang, J. Z.; Wang, L. G.; Wang, Q.; Wang, S.; Wang, X. H.; Wang, X. L.; Wang, Y. F.; Wang, Y. P.; Wang, Y. Z.; Wen, S. C.; Wang, Z. M.; Wei, D. M.; Wei, J. J.; Wei, Y. F.; Wu, D.; Wu, J.; Wu, L. B.; Wu, S. S.; Wu, X.; Xi, K.; Xia, Z. Q.; Xin, Y. L.; Xu, H. T.; Xu, Z. L.; Xu, Z. Z.; Xue, G. F.; Yang, H. B.; Yang, P.; Yang, Y. Q.; Yang, Z. L.; Yao, H. J.; Yu, Y. H.; Yuan, Q.; Yue, C.; Zang, J. J.; Zhang, C.; Zhang, D. L.; Zhang, F.; Zhang, J. B.; Zhang, J. Y.; Zhang, J. Z.; Zhang, L.; Zhang, P. F.; Zhang, S. X.; Zhang, W. Z.; Zhang, Y.; Zhang, Y. J.; Zhang, Y. Q.; Zhang, Y. L.; Zhang, Y. P.; Zhang, Z.; Zhang, Z. Y.; Zhao, H.; Zhao, H. Y.; Zhao, X. F.; Zhou, C. Y.; Zhou, Y.; Zhu, X.; Zhu, Y.; Zimmer, S.

    2017-12-01

    High-energy cosmic-ray electrons and positrons (CREs), which lose energy quickly during their propagation, provide a probe of Galactic high-energy processes and may enable the observation of phenomena such as dark-matter particle annihilation or decay. The CRE spectrum has been measured directly up to approximately 2 teraelectronvolts in previous balloon- or space-borne experiments, and indirectly up to approximately 5 teraelectronvolts using ground-based Cherenkov γ-ray telescope arrays. Evidence for a spectral break in the teraelectronvolt energy range has been provided by indirect measurements, although the results were qualified by sizeable systematic uncertainties. Here we report a direct measurement of CREs in the energy range 25 gigaelectronvolts to 4.6 teraelectronvolts by the Dark Matter Particle Explorer (DAMPE) with unprecedentedly high energy resolution and low background. The largest part of the spectrum can be well fitted by a ‘smoothly broken power-law’ model rather than a single power-law model. The direct detection of a spectral break at about 0.9 teraelectronvolts confirms the evidence found by previous indirect measurements, clarifies the behaviour of the CRE spectrum at energies above 1 teraelectronvolt and sheds light on the physical origin of the sub-teraelectronvolt CREs.

  16. Nondestructive diagnostic for electron bunch length in accelerators using the wakefield radiation spectrum

    Directory of Open Access Journals (Sweden)

    S. V. Shchelkunov

    2005-06-01

    Full Text Available We report the development of a nondestructive technique to measure bunch rms length in the psec range and below, and eventually in the fsec range, by measuring the high-frequency spectrum of wakefield radiation which is caused by the passage of a relativistic electron bunch through a channel surrounded by a dielectric. We demonstrate numerically that the generated spectrum is determined by the rms bunch length, while the specific axial and longitudinal charge distribution is not important. Measurement of the millimeter-wave spectrum will determine the rms bunch length in the psec range. This has been done using a series of calibrated mesh filters and the charge bunches produced by the 50 MeV rf linac system at ATF (Accelerator Test Facility, Brookhaven. We have developed the analysis of the factors crucial for achieving good accuracy in this measurement, and find the experimental data are fully understood by the theory. We point out that this technique also may be used for measuring fsec bunch lengths, using a prepared planar wakefield microstructure.

  17. Modulation of Electronic and Optical Anisotropy Properties of ML-GaS by Vertical Electric Field

    Science.gov (United States)

    Guo, Fei; Wu, Yaping; Wu, Zhiming; Ke, Congming; Zhou, Changjie; Chen, Ting; Li, Heng; Zhang, Chunmiao; Fu, Mingming; Kang, Junyong

    2017-06-01

    We investigate the electric-field-dependent optical properties and electronic behaviors of GaS monolayer by using the first-principles calculations. A reversal of the dipole transition from E//c to E⊥c anisotropy is found with a critical external electric field of about 5 V/nm. Decomposed projected band contributions exhibit asymmetric electronic structures in GaS interlayers under the external electric field, which explains the evolution of the absorption preference. Spatial distribution of the partial charge and charge density difference reveal that the strikingly reversed optical anisotropy in GaS ML is closely linked to the additional crystal field originated from the external electric field. These results pave the way for experimental research and provide a new perspective for the application of the monolayer GaS-based two-dimensional electronic and optoelectronic devices.

  18. Lead distribution and possible sources along vertical zone spectrum of typical ecosystems in the Gongga Mountain, eastern Tibetan Plateau

    Science.gov (United States)

    Luo, Ji; Tang, Ronggui; Sun, Shouqin; Yang, Dandan; She, Jia; Yang, Peijun

    2015-08-01

    A total of 383 samples from soil, plant, litterfall and precipitation in four typical ecosystems of Gongga Mountain were collected. Pb concentrations of samples were measured and analyzed. The results showed mean Pb concentrations in different soil layers were in the order of O > A > C, and mean Pb concentrations of the aboveground parts of plant was 3.60 ± 2.54 mg kg-1, with the minimum value of 0.77 mg kg-1 and the maximum value of 10.90 mg kg-1. Pb concentrations in soil's O-horizon and A-horizon showed a downward trend with increasing elevation (the determination coefficient R2 was 0.9478, 0.7918 and 0.9759 respectively). In contrast to other soil layers, the level of Pb concentrations in O-horizon (incomplete decomposition) was significantly high. Litterfall decomposition, atmospheric deposition and the unique climate could be main factors leading high Pb accumulation in soil's O-horizon. What's more, significant correlation (R2 = 0.8126, P mining activities and increasing anthropogenic activities (tourism development) could be main sources of Pb in this area. In order to better understand Pb sources and eco-risks of these typical ecosystems, litterfall decomposition characteristics, biomass of productivity of forest ecosystem, Pb isotopic tracing among air mass, twigs, leaves, litterfall and O-horizon soil in this vertical belt should also be taken into consideration.

  19. Comparison of Ionospheric Vertical Total Electron Content modelling approaches using spline based representations

    Science.gov (United States)

    Krypiak-Gregorczyk, Anna; Wielgosz, Pawel; Borkowski, Andrzej; Schmidt, Michael; Erdogan, Eren; Goss, Andreas

    2017-04-01

    Since electromagnetic measurements show dispersive characteristics, accurate modelling of the ionospheric electron content plays an important role for positioning and navigation applications to mitigate the effect of the ionospheric disturbances. Knowledge about the ionosphere contributes to a better understanding of space weather events as well as to forecast these events to enable protective measures in advance for electronic systems and satellite missions. In the last decades, advances in satellite technologies, data analysis techniques and models together with a rapidly growing number of analysis centres allow modelling the ionospheric electron content with an unprecedented accuracy in (near) real-time. In this sense, the representation of electron content variations in time and space with spline basis functions has gained practical importance in global and regional ionosphere modelling. This is due to their compact support and their flexibility to handle unevenly distributed observations and data gaps. In this contribution, the performances of two ionosphere models from UWM and DGFI-TUM, which are developed using spline functions are evaluated. The VTEC model of DGFI-TUM is based on tensor products of trigonometric B-spline functions in longitude and polynomial B-spline functions in latitude for a global representation. The UWM model uses two dimensional planar thin plate spline (TPS) with the Universal Transverse Mercator representation of ellipsoidal coordinates. In order to provide a smooth VTEC model, the TPS minimizes both, the squared norm of the Hessian matrix and deviations between data points and the model. In the evaluations, the differenced STEC analysis method and Jason-2 altimetry comparisons are applied.

  20. Electronic states in vertically ordered Ge/Si quantum dots detected by photocurrent spectroscopy

    Science.gov (United States)

    Yakimov, A. I.; Kirienko, V. V.; Armbrister, V. A.; Bloshkin, A. A.; Dvurechenskii, A. V.

    2014-07-01

    We report on intraband photocurrent spectroscopy of sixfold stacked Ge/Si quantum dots embedded in a Si matrix and aligned along the growth direction. The dots are formed in a shape of pyramids with the average lateral size of 18 nm. The n-type heterostructures show broad spectral response ranging from 5 to 20 μm, depending on the polarization of the incoming infrared light. The normal incidence photocurrent peak centered around 12-15 μm is attributed to the transitions from the electron states localized in the Si region adjacent to the dots to continuum states of the Si matrix. The electron confinement is caused by a modification of the conduction band alignment induced by inhomogeneous tensile strain in Si around the buried Ge/Si quantum dots. Using the Ge content and dot shape determined by Raman and scanning tunneling microscopy analysis as input parameters for three-dimensional band structure simulations, a good agreement between measured and calculated electron binding energy is obtained. Photoluminescence spectroscopy and measurements of temperature dependence of dark conductance are used to correlate photocurrent results.

  1. Topside ionospheric vertical electron density profile reconstruction using GPS and ionosonde data: possibilities for South Africa

    Directory of Open Access Journals (Sweden)

    P. Sibanda

    2011-02-01

    Full Text Available Successful empirical modeling of the topside ionosphere relies on the availability of good quality measured data. The Alouette, ISIS and Intercosmos-19 satellite missions provided large amounts of topside sounder data, but with limited coverage of relevant geophysical conditions (e.g., geographic location, diurnal, seasonal and solar activity by each individual mission. Recently, methods for inferring the electron density distribution in the topside ionosphere from Global Positioning System (GPS-based total electron content (TEC measurements have been developed. This study is focused on the modeling efforts in South Africa and presents the implementation of a technique for reconstructing the topside ionospheric electron density (Ne using a combination of GPS-TEC and ionosonde measurements and empirically obtained Upper Transition Height (UTH. The technique produces reasonable profiles as determined by the global models already in operation. With the added advantage that the constructed profiles are tied to reliable measured GPS-TEC and the empirically determined upper transition height, the technique offers a higher level of confidence in the resulting Ne profiles.

  2. Transmission electron microscopy study of vertical quantum dots molecules grown by droplet epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Maldonado, D., E-mail: david.hernandez@uca.es [Departamento de Ciencia de los Materiales e I.M. y Q.I., Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain); Herrera, M.; Sales, D.L. [Departamento de Ciencia de los Materiales e I.M. y Q.I., Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain); Alonso-Gonzalez, P.; Gonzalez, Y.; Gonzalez, L. [Instituto de Microelectronica de Madrid (CNM-CSIC), Isaac Newton 8 (PTM), 28760 Tres Cantos, Madrid (Spain); Pizarro, J.; Galindo, P.L. [Departamento de Lenguajes y Sistemas Informaticos, CASEM, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain); Molina, S.I. [Departamento de Ciencia de los Materiales e I.M. y Q.I., Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain)

    2010-07-01

    The compositional distribution of InAs quantum dots grown by molecular beam epitaxy on GaAs capped InAs quantum dots has been studied in this work. Upper quantum dots are nucleated preferentially on top of the quantum dots underneath, which have been nucleated by droplet epitaxy. The growth process of these nanostructures, which are usually called as quantum dots molecules, has been explained. In order to understand this growth process, the analysis of the strain has been carried out from a 3D model of the nanostructure built from transmission electron microscopy images sensitive to the composition.

  3. Extension of the electronic gamma-ray Spectrum Catalogue Web Site

    Science.gov (United States)

    Gehrke, R. J.; Mandler, J. W.; Helmer, R. G.; Davidson, J. R.

    2001-07-01

    The electronic version of the γ-Ray Spectrum Catalogue, at the Web Site http://id.inel.gov/gamma/, has been extended to include additional radionuclides measured with modern Ge detectors. The set of data for each nuclide includes a new spectral plot, a complete decay scheme, and a table of γ-ray energies and intensities downloaded from the Evaluated Nuclear Structure Data File (ENSDF). Each γ-ray is color coded in the same way in each of these three presentations. γ rays from daughter activities are identified in the spectrum by labeling the peak with the isotope with which it belongs. X-rays, artifact peaks (e.g., sum peaks), and contaminant radionuclides are distinctly colored. For each available nuclide, any available spectra from the earlier NaI(Tl) and Ge(Li) Catalogues have been included. The date of all of the downloaded ENSDF data is also recorded to provide a pedigree. Actinide decay chains allow hot links to other members of the decay chain. Links to other user information resources have been included.

  4. Can X-ray spectrum imaging replace backscattered electrons for compositional contrast in the scanning electron microscope?

    Science.gov (United States)

    Newbury, Dale E; Ritchie, Nicholas W M

    2011-01-01

    The high throughput of the silicon drift detector energy dispersive X-ray spectrometer (SDD-EDS) enables X-ray spectrum imaging (XSI) in the scanning electron microscope to be performed in frame times of 10-100 s, the typical time needed to record a high-quality backscattered electron (BSE) image. These short-duration XSIs can reveal all elements, except H, He, and Li, present as major constituents, defined as 0.1 mass fraction (10 wt%) or higher, as well as minor constituents in the range 0.01-0.1 mass fraction, depending on the particular composition and possible interferences. Although BSEs have a greater abundance by a factor of 100 compared with characteristic X-rays, the strong compositional contrast in element-specific X-ray maps enables XSI mapping to compete with BSE imaging to reveal compositional features. Differences in the fraction of the interaction volume sampled by the BSE and X-ray signals lead to more delocalization of the X-ray signal at abrupt compositional boundaries, resulting in poorer spatial resolution. Improved resolution in X-ray elemental maps occurs for the case of a small feature composed of intermediate to high atomic number elements embedded in a matrix of lower atomic number elements. XSI imaging strongly complements BSE imaging, and the SDD-EDS technology enables an efficient combined BSE-XSI measurement strategy that maximizes the compositional information. If 10 s or more are available for the measurement of an area of interest, the analyst should always record the combined BSE-XSI information to gain the advantages of both measures of compositional contrast. Copyright © 2011 Wiley Periodicals, Inc.

  5. Synthesis and unusual electron paramagnetic resonance spectrum of metastable nanoclusters of ZnO semiconductor crystallites.

    Science.gov (United States)

    Ram, S; Kundu, T K

    2004-11-01

    Metastable nanoclusters of ZnO semiconductor crystallites, 20 to 30 nm diameter, are synthesized by a reconstructive decomposition of a polymer precursor of dispersed Zn2+ cations in poly vinyl alcohol (PVA) polymer molecules. They have EPR (electron paramagnetic resonance) spectrum of distinct excitonic features. Multiple EPR bands appear in prominent intensities in oxygen vacancies VO+ and singly ionized Oi- and Zn(i)+ interstitials. A paramagnetic VO+ vacancy derives from usual diamagnetic O2- vacancy of VO++ (behaves as if doubly charged compared to the lattice) by addition of one electron. The results demonstrate the existence of a surface-interface or surface barrier layer in free-carrier depletion at the crystallite surface in the clusters and its effects on the Oi- and Zn(i)+ ionization states (determine green photoluminescence). Both VO+ and Zn(i)+ are curable by a thermal annealing in O2 gas. A cured sample of equilibrium structure achieved by heating at approximately 550 degrees C has a single EPR in Oi- at g = 1.990. The results are useful in understanding their correlation with EPR and optical properties in ZnO semiconductors and devices.

  6. Exploring the Bermuda triangle of homonuclear diatomic spectroscopy: The electronic spectrum and structure of Ge2

    Science.gov (United States)

    Hostutler, David A.; Li, Haiyang; Clouthier, Dennis J.; Wannous, Ghassan

    2002-03-01

    The optical spectrum of jet-cooled Ge2 has been observed for the first time. Laser-induced fluorescence (LIF) and wavelength resolved emission spectra were recorded using the pulsed discharge technique with a tetramethylgermane precursor. Analysis of the spectra yielded the vibrational constants ωe″=287.9(47), ωexe″=0.81(55), ωeye″=0.0037(18), ωe'=189.0(15), ωexe'=6.41(30), and Te'=20 610.8(16) cm-1. High-resolution rotationally resolved spectra of several bands of 74Ge2 show two strong P and R branches and two very weak Q branches. We have assigned the band system as a Hund's case (c) Ω'=1-Ω″=1 transition from the ground 3Σg- state to a 3Σu- excited state. The bond lengths derived from the rotational constants are r0″=2.3680(1) Å and re'=2.5244(18) Å, an ˜0.16 Å increase on electronic excitation. Arguments are presented for assigning the transition to a σg2πu2→σg2πuπg electron promotion, although the observed increase in the bond length is much less than predicted by previous ab initio calculations. The absence of the 0u+-0g+ component in the spectra has been attributed to an excited state predissociation.

  7. Vertical Electronic Excitations in Solution with the EOM-CCSD Method Combined with a Polarizable Explicit/Implicit Solvent Model.

    Science.gov (United States)

    Caricato, Marco; Lipparini, Filippo; Scalmani, Giovanni; Cappelli, Chiara; Barone, Vincenzo

    2013-07-09

    The accurate calculation of electronic transition energies and properties of isolated chromophores is not sufficient to provide a realistic simulation of their excited states in solution. In fact, the solvent influences the solute geometry, electronic structure, and response to external fields. Therefore, a proper description of the solvent effect is fundamental. This can be achieved by combining polarizable explicit and implicit representations of the solvent. The former provides a realistic description of solvent molecules around the solute, while the latter introduces the electrostatic effect of the bulk solution and reduces the need of too large a number of explicit solvent molecules. This strategy is particularly appealing when an accurate method such as equation of motion coupled cluster singles and doubles (EOM-CCSD) is employed for the treatment of the chromophore. In this contribution, we present the coupling of EOM-CCSD with a fluctuating charges (FQ) model and polarizable continuum model (PCM) of solvation for vertical excitations in a state-specific framework. The theory, implementation, and prototypical applications of the method are presented. Numerical tests on small solute-water clusters show very good agreement between full EOM-CCSD and EOM-CCSD-FQ calculations, with and without PCM, with differences ≤ 0.1 eV. Additionally, approximated schemes that further reduce the computational cost of the method are introduced and showed to perform well compared to the full method (errors ≤ 0.1 eV).

  8. The lineshape of the electronic spectrum of the green fluorescent protein chromophore, part II: solution phase.

    Science.gov (United States)

    Avila Ferrer, Francisco J; Davari, Mehdi D; Morozov, Dmitry; Groenhof, Gerrit; Santoro, Fabrizio

    2014-10-20

    The vibronic spectra of the green fluorescent protein chromophore analogues p-hydroxybenzylidene-2,3-dimethylimidazolinone (HBDI) and 3,5-tert-butyl-HBDI (35Bu) are similar in the vacuum, but very different in water or ethanol. To understand this difference, we have computed the vibrationally resolved solution spectra of these chromophores, using the polarizable continuum model (PCM) to account for solvent effects on the (harmonic) potential energy surfaces (PES). In agreement with experiment, we found that the vibrational progression increases with the polarity of the solvent, but we could neither reproduce the broadening, nor the large difference between the absorption spectra of HBDI and 35Bu. To account for the inhomogeneous broadening of the solution spectra, we used two approaches. In the first, we estimated the polar broadening from the solvent reorganization energy upon photo-excitation, using the state-specific PCM implementation. In the second, we estimated the broadening from the variance of the vertical excitation energies in molecular dynamics trajectories. Although we found good agreement for the lineshape of 35Bu in ethanol, and to a lesser extent in water, we highly underestimated the broadening for HBDI. To resolve this discrepancy, we explored the PES of HBDI in water and found that in contrast to the PCM result, the ground-state geometry is not planar in explicit solvent. We furthermore found that nonplanar geometries enhance the intramolecular charge transfer upon excitation. Therefore, the solvent reorganization and broadening are much larger and we speculate that the much broader spectrum of HBDI in water is due to the population of nonplanar geometries. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Are models predicting a realistic picture of vertical total electron content?

    Science.gov (United States)

    CoïSson, P.; Radicella, S. M.; Leitinger, R.; Ciraolo, L.

    2004-02-01

    The present work analyzes results coming from global maps of ionospheric total electron content (TEC) obtained from observations and from different empirical models like the International Reference Ionosphere (IRI), the model family developed at Trieste and Graz (NeQuick, COSTprof, and NeUoG-plas), and the GPS operational model (formulation by J. A. Klobuchar). Since they still appear in the context of assessment studies we have also included "old" models like the Bent model. The attention is focused on situations which occurred in the present period of high solar activity, pointing out features like the equatorial anomaly and polar regions, which are crucial test regions for ionospheric TEC models. Experimental estimates of slant TEC from International GPS Service (IGS) stations have been compared particularly with the predictions of the NeQuick and GPS models. A very simple picture of the ionosphere like the one given by the GPS operational model appears to be insufficient to reproduce the global complex behavior of the ionosphere, as it is needed for assessment studies or for modern operational real-time corrections of transionospheric propagation errors. The IRI estimates of TEC still present serious problems, essentially owing to the topside under high solar activity conditions, and the model cannot be integrated to heights above 2000 km. With processing resources suitable for real-time operation, it seems that the NeQuick model can give a more widely reliable picture of the TEC estimated from GPS measurements. Computing times for this model are considerably smaller than for more complex models like NeUoG-plas.

  10. Review of Twenty-First Century Portable Electronic Devices for Persons with Moderate Intellectual Disabilities and Autism Spectrum Disorders

    Science.gov (United States)

    Mechling, Linda C.

    2011-01-01

    Use of portable electronic devices by persons with moderate intellectual disabilities and autism spectrum disorders is gaining increased research attention. The purpose of this review was to synthesize twenty-first century literature (2000-2010) focusing on these technologies. Twenty-one studies were identified which evaluated use of: (a) handheld…

  11. An Electromagnetic Spectrum for Millennial Students: Teaching Light, Color, Energy, and Frequency Using the Electronic Devices of Our Time

    Science.gov (United States)

    Murphy, Maureen Kendrick

    2010-01-01

    In this article, a comparison of student learning outcomes is made in sophomore-level physical science classes using a "traditional" pedagogical approach versus a "modern" approach. Specifically, when students were taught the electromagnetic spectrum using diagrams and examples that incorporate technological advances and electronic devices of our…

  12. Joint estimation of vertical total electron content (VTEC) and satellite differential code biases (SDCBs) using low-cost receivers

    Science.gov (United States)

    Zhang, Baocheng; Teunissen, Peter J. G.; Yuan, Yunbin; Zhang, Hongxing; Li, Min

    2017-10-01

    Vertical total electron content (VTEC) parameters estimated using global navigation satellite system (GNSS) data are of great interest for ionosphere sensing. Satellite differential code biases (SDCBs) account for one source of error which, if left uncorrected, can deteriorate performance of positioning, timing and other applications. The customary approach to estimate VTEC along with SDCBs from dual-frequency GNSS data, hereinafter referred to as DF approach, consists of two sequential steps. The first step seeks to retrieve ionospheric observables through the carrier-to-code leveling technique. This observable, related to the slant total electron content (STEC) along the satellite-receiver line-of-sight, is biased also by the SDCBs and the receiver differential code biases (RDCBs). By means of thin-layer ionospheric model, in the second step one is able to isolate the VTEC, the SDCBs and the RDCBs from the ionospheric observables. In this work, we present a single-frequency (SF) approach, enabling the joint estimation of VTEC and SDCBs using low-cost receivers; this approach is also based on two steps and it differs from the DF approach only in the first step, where we turn to the precise point positioning technique to retrieve from the single-frequency GNSS data the ionospheric observables, interpreted as the combination of the STEC, the SDCBs and the biased receiver clocks at the pivot epoch. Our numerical analyses clarify how SF approach performs when being applied to GPS L1 data collected by a single receiver under both calm and disturbed ionospheric conditions. The daily time series of zenith VTEC estimates has an accuracy ranging from a few tenths of a TEC unit (TECU) to approximately 2 TECU. For 73-96% of GPS satellites in view, the daily estimates of SDCBs do not deviate, in absolute value, more than 1 ns from their ground truth values published by the Centre for Orbit Determination in Europe.

  13. Measurement of the Neutron Spectrum of a DD Electronic Neutron Generator

    Energy Technology Data Exchange (ETDEWEB)

    D. L. Chichester; J. T. Johnson; E. H. Seabury

    2010-08-01

    A Cuttler-Shalev (C-S) 3He proportional counter has been used to measure the energy spectrum of neutrons from a portable deuterium-deuterium electronic neutron generator. To improve the analysis of results from the C-S detector digital pulse shape analysis techniques have been used to eliminate neutron recoil artifacts in the recorded data. Data was collected using a 8-GHz, 10-bit waveform digitizer with its full scale corresponding to approximately 6-MeV neutrons. The measurements were made with the detector axis perpendicular to the direction of ions in the ENG in a plane 0.5-m to the side of the ENG, measuring neutrons emitted at an angle from 87.3? to 92.7? with respect to the path of ions in the ENG. The system demonstrated an energy resolution of approximately 0.040 MeV for the thermal peak and approximately 0.13 MeV at the DD neutron energy. In order to achieve the ultimate resolution capable with this type of detector it is clear that a higher-precision digitizer will be needed.

  14. Analysis of ionospheric vertical total electron content before the 1 April 2014 Mw 8.2 Chile earthquake

    Science.gov (United States)

    Jiang, Weiping; Ma, Yifang; Zhou, Xiaohui; Li, Zhao; An, Xiangdong; Wang, Kaihua

    2017-11-01

    This paper studies ionospheric vertical total electron content (VTEC) variations before the 1 April 2014 Mw 8.2 Chile earthquake. VTEC derived from 14 global positioning system (GPS) stations and global ionospheric map (GIM) were used to analyze ionospheric variations before the earthquake using the sliding interquartile range method, and the results showed that significant positive VTEC anomalies occurred on 28 March. To explore possible causes of these anomalies, effects of solar and geomagnetic activities were examined, and VTEC variations during 17 March to 31 March in 2009-2013 were cross-compared. Also, VTEC for a full year before the earthquake was investigated. The results indicated that the anomalies were weakly associated with high solar activities and geomagnetic storms and that the anomalies were not normal seasonal and diurnal variations. An analysis of the spatial distribution of the observed anomalies was also presented, and it demonstrated that the anomalies specifically appeared around the epicenter on 28 March. We suggest that the observed anomalies may be associated with the subsequent Chile earthquake. Equatorial anomaly variations were analyzed to discuss the possible physical mechanism, and results showed that the equatorial anomaly unusually increased on 28 March, which indicates that anomalous electric fields generated in the earthquake preparation area and the meridional wind are possible causes of the observed ionospheric anomalies.

  15. Analysis of ionospheric vertical total electron content before the 1 April 2014 Mw 8.2 Chile earthquake

    Science.gov (United States)

    Jiang, Weiping; Ma, Yifang; Zhou, Xiaohui; Li, Zhao; An, Xiangdong; Wang, Kaihua

    2017-07-01

    This paper studies ionospheric vertical total electron content (VTEC) variations before the 1 April 2014 Mw 8.2 Chile earthquake. VTEC derived from 14 global positioning system (GPS) stations and global ionospheric map (GIM) were used to analyze ionospheric variations before the earthquake using the sliding interquartile range method, and the results showed that significant positive VTEC anomalies occurred on 28 March. To explore possible causes of these anomalies, effects of solar and geomagnetic activities were examined, and VTEC variations during 17 March to 31 March in 2009-2013 were cross-compared. Also, VTEC for a full year before the earthquake was investigated. The results indicated that the anomalies were weakly associated with high solar activities and geomagnetic storms and that the anomalies were not normal seasonal and diurnal variations. An analysis of the spatial distribution of the observed anomalies was also presented, and it demonstrated that the anomalies specifically appeared around the epicenter on 28 March. We suggest that the observed anomalies may be associated with the subsequent Chile earthquake. Equatorial anomaly variations were analyzed to discuss the possible physical mechanism, and results showed that the equatorial anomaly unusually increased on 28 March, which indicates that anomalous electric fields generated in the earthquake preparation area and the meridional wind are possible causes of the observed ionospheric anomalies.

  16. Evaluation of freestanding boron-doped diamond grown by chemical vapour deposition as substrates for vertical power electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Issaoui, R.; Achard, J.; Tallaire, A.; Silva, F.; Gicquel, A. [LSPM-CNRS (formerly LIMHP), Universite Paris 13, 99, Avenue Jean-Baptiste Clement, 93430 Villetaneuse (France); Bisaro, R.; Servet, B.; Garry, G. [Thales Research and Technology France, Campus de Polytechnique, 1 Avenue Augustin Fresnel, F-91767 Palaiseau Cedex (France); Barjon, J. [GEMaC-CNRS, Universite de Versailles Saint Quentin Batiment Fermat, 45 Avenue des Etats-Unis, 78035 Versailles Cedex (France)

    2012-03-19

    In this study, 4 x 4 mm{sup 2} freestanding boron-doped diamond single crystals with thickness up to 260 {mu}m have been fabricated by plasma assisted chemical vapour deposition. The boron concentrations measured by secondary ion mass spectroscopy were 10{sup 18} to 10{sup 20} cm{sup -3} which is in a good agreement with the values calculated from Fourier transform infrared spectroscopy analysis, thus indicating that almost all incorporated boron is electrically active. The dependence of lattice parameters and crystal mosaicity on boron concentrations have also been extracted from high resolution x-ray diffraction experiments on (004) planes. The widths of x-ray rocking curves have globally shown the high quality of the material despite a substantial broadening of the peak, indicating a decrease of structural quality with increasing boron doping levels. Finally, the suitability of these crystals for the development of vertical power electronic devices has been confirmed by four-point probe measurements from which electrical resistivities as low as 0.26 {Omega} cm have been obtained.

  17. Haptophyte Diversity and Vertical Distribution Explored by 18S and 28S Ribosomal RNA Gene Metabarcoding and Scanning Electron Microscopy.

    Science.gov (United States)

    Gran-Stadniczeñko, Sandra; Šupraha, Luka; Egge, Elianne D; Edvardsen, Bente

    2017-07-01

    Haptophyta encompasses more than 300 species of mostly marine pico- and nanoplanktonic flagellates. Our aims were to investigate the Oslofjorden haptophyte diversity and vertical distribution by metabarcoding, and to improve the approach to study haptophyte community composition, richness and proportional abundance by comparing two rRNA markers and scanning electron microscopy (SEM). Samples were collected in August 2013 at the Outer Oslofjorden, Norway. Total RNA/cDNA was amplified by haptophyte-specific primers targeting the V4 region of the 18S, and the D1-D2 region of the 28S rRNA. Taxonomy was assigned using curated haptophyte reference databases and phylogenetic analyses. Both marker genes showed Chrysochromulinaceae and Prymnesiaceae to be the families with highest number of Operational Taxonomic Units (OTUs), as well as proportional abundance. The 18S rRNA data set also contained OTUs assigned to eight supported and defined clades consisting of environmental sequences only, possibly representing novel lineages from family to class. We also recorded new species for the area. Comparing coccolithophores by SEM with metabarcoding shows a good correspondence with the 18S rRNA gene proportional abundances. Our results contribute to link morphological and molecular data and 28S to 18S rRNA gene sequences of haptophytes without cultured representatives, and to improve metabarcoding methodology. © 2016 The Authors Journal of Eukaryotic Microbiology published by Wiley Periodicals, Inc. on behalf of International Society of Protistologists.

  18. Extended-Spectrum-Beta-Lactamase- and Plasmid-Encoded Cephamycinase-Producing Enterobacteria in the Broiler Hatchery as a Potential Mode of Pseudo-Vertical Transmission.

    Science.gov (United States)

    Projahn, Michaela; Daehre, Katrin; Roesler, Uwe; Friese, Anika

    2017-01-01

    Antimicrobial resistance through extended-spectrum beta-lactamases (ESBLs) and transferable (plasmid-encoded) cephamycinases (pAmpCs) represents an increasing problem in human and veterinary medicine. The presence of ESBL-/pAmpC-producing commensal enterobacteria in farm animals, such as broiler chickens, is considered one possible source of food contamination and could therefore also be relevant for human colonization. Studies on transmission routes along the broiler production chain showed that 1-day-old hatchlings are already affected. In this study, ESBL-/pAmpC-positive broiler parent flocks and their corresponding eggs, as well as various environmental and air samples from the hatchery, were analyzed. The eggs were investigated concerning ESBL-/pAmpC-producing enterobacteria on the outer eggshell surface (before/after disinfection), the inner eggshell surface, and the egg content. Isolates were analyzed concerning their species, their phylogroup in the case of Escherichia coli strains, the respective resistance genes, and the phenotypical antibiotic resistance. Of the tested eggs, 0.9% (n = 560) were contaminated on their outer shell surface. Further analyses using pulsed-field gel electrophoresis showed a relationship of these strains to those isolated from the corresponding parent flocks, which demonstrates a pseudo-vertical transfer of ESBL-/pAmpC-producing enterobacteria into the hatchery. Resistant enterobacteria were also found in environmental samples from the hatchery, such as dust or surfaces which could pose as a possible contamination source for the hatchlings. All 1-day-old chicks tested negative directly after hatching. The results show a possible entry of ESBL-/pAmpC-producing enterobacteria from the parent flocks into the hatchery; however, the impact of the hatchery on colonization of the hatchlings seems to be low. ESBL-/pAmpC-producing enterobacteria occur frequently in broiler-fattening farms. Recent studies investigated the prevalence and

  19. Electronic Health Record Based Algorithm to Identify Patients with Autism Spectrum Disorder.

    Directory of Open Access Journals (Sweden)

    Todd Lingren

    Full Text Available Cohort selection is challenging for large-scale electronic health record (EHR analyses, as International Classification of Diseases 9th edition (ICD-9 diagnostic codes are notoriously unreliable disease predictors. Our objective was to develop, evaluate, and validate an automated algorithm for determining an Autism Spectrum Disorder (ASD patient cohort from EHR. We demonstrate its utility via the largest investigation to date of the co-occurrence patterns of medical comorbidities in ASD.We extracted ICD-9 codes and concepts derived from the clinical notes. A gold standard patient set was labeled by clinicians at Boston Children's Hospital (BCH (N = 150 and Cincinnati Children's Hospital and Medical Center (CCHMC (N = 152. Two algorithms were created: (1 rule-based implementing the ASD criteria from Diagnostic and Statistical Manual of Mental Diseases 4th edition, (2 predictive classifier. The positive predictive values (PPV achieved by these algorithms were compared to an ICD-9 code baseline. We clustered the patients based on grouped ICD-9 codes and evaluated subgroups.The rule-based algorithm produced the best PPV: (a BCH: 0.885 vs. 0.273 (baseline; (b CCHMC: 0.840 vs. 0.645 (baseline; (c combined: 0.864 vs. 0.460 (baseline. A validation at Children's Hospital of Philadelphia yielded 0.848 (PPV. Clustering analyses of comorbidities on the three-site large cohort (N = 20,658 ASD patients identified psychiatric, developmental, and seizure disorder clusters.In a large cross-institutional cohort, co-occurrence patterns of comorbidities in ASDs provide further hypothetical evidence for distinct courses in ASD. The proposed automated algorithms for cohort selection open avenues for other large-scale EHR studies and individualized treatment of ASD.

  20. Multifractal analysis of vertical total electron content (VTEC at equatorial region and low latitude, during low solar activity

    Directory of Open Access Journals (Sweden)

    M. J. A. Bolzan

    2013-01-01

    Full Text Available This paper analyses the multifractal aspects of the GPS data (measured during a period of low solar activity obtained from two Brazilian stations: Belém (01.3° S, 48.3° W and São José dos Campos (SJC (23.2° S, 45.9° W. The results show that the respective geographic sites show important scaling differences as well as similarities when their multifractal signatures for vertical total electron content (VTEC are compared. The f(α spectra have a narrow shape for great scales, which indicates the predominance of deterministic phenomena, such as solar rotation (27 days over intermittent phenomena. Furthermore, the f(α spectra for both sites have a strong multifractality degree at small scales. This strong multifractality degree observed at small scales (1 to 12 h at both sites is because the ionosphere over Brazil is a non-equilibrium system. The differences found were that Belém presented a stronger multifractality at small scales (1 h to 12 h compared with SJC, particularly in 2006. The reason for this behaviour may be associated with the location of Belém, near the geomagnetic equator, where at this location the actions of X-rays, ultraviolet, and another wavelength from the Sun are more direct, strong, and constant throughout the whole year. Although the SJC site is near ionospheric equatorial anomaly (IEA peaks, this interpretation could explain the higher values found for the intermittent parameter μ for Belém compared with SJC. Belém also showed the presence of one or two flattening regions for f(α spectra at the same scales mentioned before. These differences and similarities also were interpreted in terms of the IEA content, where this phenomenon is an important source of intermittence due the presence of the VTEC peaks at ±20° geomagnetic latitudes.

  1. Multifractal analysis of vertical total electron content (VTEC at equatorial region and low latitude, during low solar activity

    Directory of Open Access Journals (Sweden)

    M. J. A. Bolzan

    2013-01-01

    Full Text Available This paper analyses the multifractal aspects of the GPS data (measured during a period of low solar activity obtained from two Brazilian stations: Belém (01.3° S, 48.3° W and São José dos Campos (SJC (23.2° S, 45.9° W. The results show that the respective geographic sites show important scaling differences as well as similarities when their multifractal signatures for vertical total electron content (VTEC are compared. The f(α spectra have a narrow shape for great scales, which indicates the predominance of deterministic phenomena, such as solar rotation (27 days over intermittent phenomena. Furthermore, the f(α spectra for both sites have a strong multifractality degree at small scales. This strong multifractality degree observed at small scales (1 to 12 h at both sites is because the ionosphere over Brazil is a non-equilibrium system. The differences found were that Belém presented a stronger multifractality at small scales (1 h to 12 h compared with SJC, particularly in 2006. The reason for this behaviour may be associated with the location of Belém, near the geomagnetic equator, where at this location the actions of X-rays, ultraviolet, and another wavelength from the Sun are more direct, strong, and constant throughout the whole year. Although the SJC site is near ionospheric equatorial anomaly (IEA peaks, this interpretation could explain the higher values found for the intermittent parameter μ for Belém compared with SJC. Belém also showed the presence of one or two flattening regions for f(α spectra at the same scales mentioned before. These differences and similarities also were interpreted in terms of the IEA content, where this phenomenon is an important source of intermittence due the presence of the VTEC peaks at ±20° geomagnetic latitudes.

  2. Improving the Automatic Inversion of Digital ISIS-2 Ionogram Reflection Traces into Topside Vertical Electron-Density Profiles

    Science.gov (United States)

    Benson, R. F.; Truhlik, V.; Huang, X.; Wang, Y.; Bilitza, D.

    2011-01-01

    The topside-sounders on the four satellites of the International Satellites for Ionospheric Studies (ISIS) program were designed as analog systems. The resulting ionograms were displayed on 35-mm film for analysis by visual inspection. Each of these satellites, launched between 1962 and 1971, produced data for 10 to 20 years. A number of the original telemetry tapes from this large data set have been converted directly into digital records. Software, known as the TOPside Ionogram Scalar with True-height (TOPIST) algorithm has been produced that enables the automatic inversion of ISIS-2 ionogram reflection traces into topside vertical electron-density profiles Ne(h). More than million digital Alouette/ISIS topside ionograms have been produced and over 300,000 are from ISIS 2. Many of these ISIS-2 ionograms correspond to a passive mode of operation for the detection of natural radio emissions and thus do not contain ionospheric reflection traces. TOPIST, however, is not able to produce Ne(h) profiles from all of the ISIS-2 ionograms with reflection traces because some of them did not contain frequency information. This information was missing due to difficulties encountered during the analog-to-digital conversion process in the detection of the ionogram frame-sync pulse and/or the frequency markers. Of the many digital topside ionograms that TOPIST was able to process, over 200 were found where direct comparisons could be made with Ne(h) profiles that were produced by manual scaling in the early days of the ISIS program. While many of these comparisons indicated excellent agreement (inversion process: (1) improve the quality of the digital ionogram database by remedying the missing frequency-information problem when possible, and (2) using the above-mentioned comparisons as teaching examples of how to improve the original TOPIST software.

  3. Atmospheric muon and electron neutrino energy spectrum measured by first year of IceCube-86 detector

    Science.gov (United States)

    Kuwabara, Takao; IceCube Collaboration

    2017-09-01

    The flux of atmospheric neutrinos is the main background for searches for cosmic neutrinos. Precise measurement of its spectrum allows us to reduce uncertainty of any kind of signal analysis. A unified analysis of atmospheric neutrinos using data collected with the full IceCube detector between May 2011 and May 2012 is presented in which both muon and electron flavors are included in a single framework.

  4. Calculation on spectrum of direct DNA damage induced by low-energy electrons including dissociative electron attachment.

    Science.gov (United States)

    Liu, Wei; Tan, Zhenyu; Zhang, Liming; Champion, Christophe

    2017-03-01

    In this work, direct DNA damage induced by low-energy electrons (sub-keV) is simulated using a Monte Carlo method. The characteristics of the present simulation are to consider the new mechanism of DNA damage due to dissociative electron attachment (DEA) and to allow determining damage to specific bases (i.e., adenine, thymine, guanine, or cytosine). The electron track structure in liquid water is generated, based on the dielectric response model for describing electron inelastic scattering and on a free-parameter theoretical model and the NIST database for calculating electron elastic scattering. Ionization cross sections of DNA bases are used to generate base radicals, and available DEA cross sections of DNA components are applied for determining DNA-strand breaks and base damage induced by sub-ionization electrons. The electron elastic scattering from DNA components is simulated using cross sections from different theoretical calculations. The resulting yields of various strand breaks and base damage in cellular environment are given. Especially, the contributions of sub-ionization electrons to various strand breaks and base damage are quantitatively presented, and the correlation between complex clustered DNA damage and the corresponding damaged bases is explored. This work shows that the contribution of sub-ionization electrons to strand breaks is substantial, up to about 40-70%, and this contribution is mainly focused on single-strand break. In addition, the base damage induced by sub-ionization electrons contributes to about 20-40% of the total base damage, and there is an evident correlation between single-strand break and damaged base pair A-T.

  5. Multiconfigurational spin tensor electron propagator vertical ionization potentials for O2: Comparison to some other forefront methods using the same basis sets and geometries

    Science.gov (United States)

    Heryadi, Dodi; Yeager, Danny L.; Golab, Joseph T.; Nichols, Jeffrey A.

    1995-06-01

    In a recent paper in The Journal of Chemical Physics, we showed the potential energy curves for several cation states of O2 obtained using the multiconfigurational spin tensor electron propagator method (MCSTEP) with a basis set. In this communication we present vertical ionization potential calculations to the same O2 states. However, for the results reported here, exactly the same basis sets and geometries are used that were used for two other forefront methods; the coupled-cluster reference electron propagator theory (CC-EPT) and the Fock space multireference coupled-cluster method (FSMRCC). Hence, more direct comparisons and contrasts among these methods are now available.

  6. A New Inversion Routine to Produce Vertical Electron-Density Profiles from Ionospheric Topside-Sounder Data

    Science.gov (United States)

    Wang, Yongli; Benson, Robert F.

    2011-01-01

    Two software applications have been produced specifically for the analysis of some million digital topside ionograms produced by a recent analog-to-digital conversion effort of selected analog telemetry tapes from the Alouette-2, ISIS-1 and ISIS-2 satellites. One, TOPIST (TOPside Ionogram Scalar with True-height algorithm) from the University of Massachusetts Lowell, is designed for the automatic identification of the topside-ionogram ionospheric-reflection traces and their inversion into vertical electron-density profiles Ne(h). TOPIST also has the capability of manual intervention. The other application, from the Goddard Space Flight Center based on the FORTRAN code of John E. Jackson from the 1960s, is designed as an IDL-based interactive program for the scaling of selected digital topside-sounder ionograms. The Jackson code has also been modified, with some effort, so as to run on modern computers. This modification was motivated by the need to scale selected ionograms from the millions of Alouette/ISIS topside-sounder ionograms that only exist on 35-mm film. During this modification, it became evident that it would be more efficient to design a new code, based on the capabilities of present-day computers, than to continue to modify the old code. Such a new code has been produced and here we will describe its capabilities and compare Ne(h) profiles produced from it with those produced by the Jackson code. The concept of the new code is to assume an initial Ne(h) and derive a final Ne(h) through an iteration process that makes the resulting apparent-height profile fir the scaled values within a certain error range. The new code can be used on the X-, O-, and Z-mode traces. It does not assume any predefined profile shape between two contiguous points, like the exponential rule used in Jackson s program. Instead, Monotone Piecewise Cubic Interpolation is applied in the global profile to keep the monotone nature of the profile, which also ensures better smoothness

  7. On Possible Interpretations of the High Energy Electron-Positron Spectrum Measured by the Fermi Large Area Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Grasso, D.; Profumo, S.; Strong, A.W.; Baldini, L.; Bellazzini, R.; Bloom, E.D.; Bregeon, J.; Di Bernardo, G.; Gaggero, D.; Giglietto, N.; Kamae, T.; Latronico, L.; Longo, F.; Mazziotta, M.N.; Moiseev, A.A.; Morselli, A.; Ormes, J.F.; Pesce-Rollins, M.; Pohl, M.; Razzano, M.; Sgro, C.

    2009-05-15

    The Fermi-LAT experiment recently reported high precision measurements of the spectrum of cosmic-ray electrons-plus-positrons (CRE) between 20 GeV and 1 TeV. The spectrum shows no prominent spectral features, and is significantly harder than that inferred from several previous experiments. Here we discuss several interpretations of the Fermi results based either on a single large scale Galactic CRE component or by invoking additional electron-positron primary sources, e.g. nearby pulsars or particle Dark Matter annihilation. We show that while the reported Fermi-LAT data alone can be interpreted in terms of a single component scenario, when combined with other complementary experimental results, specifically the CRE spectrum measured by H.E.S.S. and especially the positron fraction reported by PAMELA between 1 and 100 GeV, that class of models fails to provide a consistent interpretation. Rather, we find that several combinations of parameters, involving both the pulsar and dark matter scenarios, allow a consistent description of those results. We also briefly discuss the possibility of discriminating between the pulsar and dark matter interpretations by looking for a possible anisotropy in the CRE flux.

  8. Auroral E-region electron density height profile modificationby electric field driven vertical plasma transport:some evidence in EISCAT CP-1 data statistics

    Directory of Open Access Journals (Sweden)

    T. Bösinger

    2004-03-01

    Full Text Available A model developed several years ago by Huuskonen et al. (1984 predicted that vertical transport of ions in the nocturnal auroral E-region ionosphere can shift the electron density profiles in altitude during times of sufficiently large electric fields. If the vertical plasma transport effect was to operate over a sufficiently long enough time, then the real height of the E-region electron maximum should be shifted some km upwards (downwards in the eastward (westward auroral electrojet, respectively, when the electric field is strong, exceeding, say, 50 mV/m. Motivated by these predictions and the lack of any experimental verification so far, we made use of the large database of the European Incoherent Scatter (EISCAT radar to investigate if the anticipated vertical plasma transport is at work in the auroral E-region ionosphere and thus to test the Huuskonen et al. (1984 model. For this purpose a new type of EISCAT data display was developed which enabled us to order a large number of electron density height profiles, collected over 16 years of EISCAT operation, according to the electric field magnitude and direction as measured at the same time at the radar's magnetic field line in the F-region. Our analysis shows some signatures in tune with a vertical plasma transport in the auroral E-region of the type predicted by the Huuskonen et al. model. The evidence brought forward is, however, not unambiguous and requires more rigorous analysis.

    Key words. Ionosphere (auroral ionosphere; plasma convection; electric fields and currents

  9. Electronic Screen Media for Persons with Autism Spectrum Disorders: Results of a Survey

    Science.gov (United States)

    Shane, Howard C.; Albert, Patti Ducoff

    2008-01-01

    Social and anecdotal reports suggest a predilection for visual media among individuals on the autism spectrum, yet no formal investigation has explored the extent of that use. Using a distributed questionnaire design, parents and caregivers report on time allotted toward media, including observable behaviors and communicative responses. More time…

  10. On ion gyro-harmonic structuring in the stimulated electromagnetic emission spectrum during second electron gyro-harmonic heating

    Science.gov (United States)

    Samimi, A.; Scales, W. A.; Bernhardt, P. A.; Briczinski, S. J.; Selcher, C. A.; McCarrick, M. J.

    2012-11-01

    Recent observations show that, during ionospheric heating experiments at frequencies near the second electron gyro-harmonic, discrete spectral lines separated by harmonics of the ion-gyro frequency appear in the stimulated electromagnetic emission (SEE) spectrum within 1 kHz of the pump frequency. In addition to the ion gyro-harmonic structures, on occasion, a broadband downshifted emission is observed simultaneously with these spectral lines. Parametric decay of the pump field into upper hybrid/electron Bernstein (UH/EB) and low-frequency ion Bernstein (IB) and oblique ion acoustic (IA) modes is considered responsible for generation of these spectral features. Guided by predictions of an analytical model, a two-dimensional particle-in-cell (PIC) computational model is employed to study the nonlinear processes during such heating experiments. The critical parameters that affect the spectrum, such as whether discrete gyro-harmonic on broadband structures is observed, include angle of the pump field relative to the background magnetic field, pump field strength, and proximity of the pump frequency to the gyro-harmonic. Significant electron heating along the magnetic field is observed in the parameter regimes considered.

  11. Spectrum and angular distribution of low energy electrons from 152Eu deca

    Directory of Open Access Journals (Sweden)

    L. P. Sydorenko

    2015-04-01

    Full Text Available Angular distribution of low energy electrons from 152Eu decay was measured. Measurements were carried out in cylindrical geometry, which permits minimum distortions of data. These data confirm existence of angular distribution dependence on the energy of emitted electrons but this dependence somewhat differs from theory predicted. It is noted that the theory predicts too low intensity of near-zero energy electrons e0 (Ee ~ 1 - 2 eV emission; also, the static screening of charge used in theory should not influence the emission of e0-electrons.

  12. On the role of vertical electron density gradients in the generation of type II irregularities associated with blanketing ES (ESb) during counter equatorial electrojet events: A case study

    Science.gov (United States)

    Devasia, C. V.; Jyoti, N.; Subbarao, K. S. V.; Tiwari, Diwakar; Reddi, C. Raghava; Sridharan, R.

    2004-06-01

    The characteristics of different types of Sporadic E (ES) layers and the associated plasma density irregularities over the magnetic equator have been studied in a campaign mode using VHF backscatter radar, digital ionosonde, and ground magnetometer data from Trivandrum (dip latitude 0.5°N, geographic latitude 8.5°N, geographic longitude 77°E), India. The presence of blanketing type ES (ESb) in the ionograms with varying intensity and duration were observed in association with afternoon Counter Equatorial Electrojet (CEEJ) events. ESb was associated with intense backscatter returns and with either very low zonal electric field and/or with distortions present in the altitude profile of the drift velocity of the type II irregularities. The results of the coordinated study indicate the possible role of vertical electron density gradients in ESb layers in addition to providing evidence for the local winds to be responsible for the vertical gradients themselves.

  13. The lineshape of the electronic spectrum of the green fluorescent protein chromophore, part I: gas phase.

    Science.gov (United States)

    Davari, Mehdi D; Ferrer, Francisco J Avila; Morozov, Dmitry; Santoro, Fabrizio; Groenhof, Gerrit

    2014-10-20

    In this work we present the vibrationally resolved optical absorption spectrum of p-hydroxybenzylidene-2,3-dimethylimidazolinone (HBDI), the green fluorescent protein (GFP) chromophore, computed at several levels of theory, including time-dependent DFT with various functionals and basis sets, CASSCF, CASPT2 and XMCQDPT2. We also investigated what happens to the spectrum if the ground- and excited-state geometries are optimized at different levels of theory (mixed approach), as has been used previously. The vibrationally resolved absorption spectra obtained by DFT, CASPT2 and XMCQDPT2 are very similar and consist of a main absorption peak and a shoulder that is ∼1500 cm(-1) higher in energy. The vibrational progression increases moderately with temperature. These spectra are in qualitative agreement with experimental action spectra, but much narrower and lack the long tail in the blue, even at high temperatures. Because our calculated emission spectra, which are equally narrow, are in good agreement with the emission of green fluorescent protein at 253 K, we argue that the action spectrum are too broad to be considered as the absorption spectrum. The CASSCF method and the mixed approaches overestimate the vibrational progressions with respect to CAM-B3LYP, CASPT2 and XMCQDPT2, due to inaccuracies in the geometric S0 →S1 displacements. Finally, we computed the vibronic spectra of four chromophore analogues with different substitutions on the rings and found that these substitutions hardly affect the lineshape in vacuum. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Spectrum of fast electrons in a dense gas in the presence of a nonuniform pulsed field

    Science.gov (United States)

    Tkachev, A. N.; Yakovlenko, S. I.

    2007-01-01

    The problems of gas preionization in discharges related to laser physics are considered. The propagation of fast electrons injected from the cathode in the presence of a nonuniform nonstationary field and the motion of multiplying electrons at the edge of the avalanche in the presence of a nonuniform nonstationary field are simulated. The effect of the voltage pulse steepness and the field nonuniformity on the mean propagation velocity of fast electrons and their energy distribution is demonstrated. At certain combinations of the voltage pulse rise time and amplitude and at a certain time interval, the center of gravity of the electron cloud can move in the opposite direction relative to the direction of force acting upon electrons. It is also demonstrated that the number of hard particles (and, hence, the hard component of the x-ray bremsstrahlung) increases with both an increase in the voltage amplitude and a decrease in the pulse rise time. For nonoptimal conditions of the picosecond voltage pulse, an assumption is formulated: an electron beam in gas is formed due to the electrons at the edge of the avalanche rather than the background multiplication wave approaching the anode.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-01

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

  16. Universality of solar-wind turbulent spectrum from MHD to electron scales.

    Science.gov (United States)

    Alexandrova, O; Saur, J; Lacombe, C; Mangeney, A; Mitchell, J; Schwartz, S J; Robert, P

    2009-10-16

    To investigate the universality of magnetic turbulence in space plasmas, we analyze seven time periods in the free solar wind under different plasma conditions. Three instruments on Cluster spacecraft operating in different frequency ranges give us the possibility to resolve spectra up to 300 Hz. We show that the spectra form a quasiuniversal spectrum following the Kolmogorov's law approximately k(-5/3) at MHD scales, a approximately k(-2.8) power law at ion scales, and an exponential approximately exp[-sqrt[k(rho)e

  17. AMS-02: Cosmic electron and positron (e− + e+ spectrum up to 1 TeV

    Directory of Open Access Journals (Sweden)

    Bazo J.

    2016-01-01

    Full Text Available The AMS-02 spectrometer, on the ISS since 2011, performs highly accurate measurements of cosmic rays up to the TeV region. We review the analysis of the cosmic (e+ + e− flux in the energy range between 0.5 GeV and 1 TeV, based on 10.6 million (e+ + e− events. The high statistics and detector energy resolution allow for a study of the spectral shape of unprecedented quality, thus improving our understanding of the production, acceleration and propagation of cosmic rays. The resulting energy spectrum does not show prominent features.

  18. The H3+ rovibrational spectrum revisited with a global electronic potential energy surface

    Science.gov (United States)

    Velilla, Luis; Lepetit, Bruno; Aguado, Alfredo; Beswick, J. Alberto; Paniagua, Miguel

    2008-08-01

    In this paper, we have computed the rovibrational spectrum of the H3+ molecule using a new global potential energy surface, invariant under all permutations of the nuclei, that includes the long range electrostatic interactions analytically. The energy levels are obtained by a variational calculation using hyperspherical coordinates. From the comparison with available experimental results for low lying levels, we conclude that our accuracy is of the order of 0.1 cm-1 for states localized in the vicinity of equilateral triangular configurations of the nuclei, and changes to the order of 1 cm-1 when the system is distorted away from equilateral configurations. Full rovibrational spectra up to the H++H2 dissociation energy limit have been computed. The statistical properties of this spectrum (nearest neighbor distribution and spectral rigidity) show the quantum signature of classical chaos and are consistent with random matrix theory. On the other hand, the correlation function, even when convoluted with a smoothing function, exhibits oscillations which are not described by random matrix theory. We discuss a possible similarity between these oscillations and the ones observed experimentally.

  19. On the possibility of determining an effective energy spectrum of clinical electron beams from percentage depth dose (PDD) data of broad beams.

    Science.gov (United States)

    Zhengming, L; Jette, D

    1999-08-01

    Experiments have already shown that obvious differences exist between the dose distribution of electron beams of a clinical accelerator in a water phantom and the dose distribution of monoenergetic electrons of nominal energy of the clinical accelerator in water, because the electron beams which reach the water surface travelling through the collimation system of the accelerator are no longer monoenergetic. It is evident that, while calculating precisely the dose distribution of any incident electron beams, the energy spectrum of the incident electron beam must be taken into consideration. In this note we shall present a method for determining an effective energy spectrum of clinical electron beams from PDD data (percentage depth dose data). It is well known that there is an integral equation of the first kind which links the energy spectrum of an incident electron beam with PDD through the dose distribution of monoenergetic electrons in the medium, as a kernel function in the integral equation. In this note, the integral equation of the first kind will be solved by using the regularization method. The bipartition model of electron transport will be used to calculate the kernel function, namely the energy deposition due to monoenergetic electron beams in the medium.

  20. NOTE: On the possibility of determining an effective energy spectrum of clinical electron beams from percentage depth dose (PDD) data of broad beams

    Science.gov (United States)

    Zhengming, Luo; Jette, David

    1999-08-01

    Experiments have already shown that obvious differences exist between the dose distribution of electron beams of a clinical accelerator in a water phantom and the dose distribution of monoenergetic electrons of nominal energy of the clinical accelerator in water, because the electron beams which reach the water surface travelling through the collimation system of the accelerator are no longer monoenergetic. It is evident that, while calculating precisely the dose distribution of any incident electron beams, the energy spectrum of the incident electron beam must be taken into consideration. In this note we shall present a method for determining an effective energy spectrum of clinical electron beams from PDD data (percentage depth dose data). It is well known that there is an integral equation of the first kind which links the energy spectrum of an incident electron beam with PDD through the dose distribution of monoenergetic electrons in the medium, as a kernel function in the integral equation. In this note, the integral equation of the first kind will be solved by using the regularization method. The bipartition model of electron transport will be used to calculate the kernel function, namely the energy deposition due to monoenergetic electron beams in the medium.

  1. Pulse shape and spectrum of coherent diffraction-limited transition radiation from electron beams

    Energy Technology Data Exchange (ETDEWEB)

    van Tilborg, J.; Schroeder, C.B.; Esarey, E.; Leemans, W.P.

    2003-12-20

    The electric field in the temporal and spectral domain of coherent diffraction-limited transition radiation is studied. An electron bunch, with arbitrary longitudinal momentum distribution, propagating at normal incidence to a sharp metal-vacuum boundary with finite transverse dimension is considered. A general expression for the spatiotemporal electric field of the transition radiation is derived, and closed-form solutions for several special cases are given. The influence of parameters such as radial boundary size, electron momentum distribution, and angle of observation on the waveform (e.g., radiation pulse length and amplitude) are discussed. For a Gaussian electron bunch, the coherent radiation waveform is shown to have a single-cycle profile. Application to a novel THz source based on a laser-driven accelerator is discussed.

  2. Design and fabrication of a InGaN vertical-cavity surface-emitting laser with a composition-graded electron-blocking layer

    Science.gov (United States)

    Lin, B. C.; Chang, Y. A.; Chen, K. J.; Chiu, C. H.; Li, Z. Y.; Lan, Y. P.; Lin, C. C.; Lee, P. T.; Kuo, Y. K.; Shih, M. H.; Kuo, H. C.; Lu, T. C.; Wang, S. C.

    2014-08-01

    In this study, the design and fabrication of a InGaN vertical-cavity surface-emitting laser (VCSEL) with a composition-graded electron blocking layer (GEBL) are revealed experimentally and theoretically. It has been demonstrated that laser output performance is improved by using a GEBL when compared to the typical VCSEL structure of a rectangular EBL. The output power obtained at 20 kA cm-2 is enhanced by a factor of 3.8 by the successful reduction of threshold current density from 12.6 to 9.2 kA  cm-2 and the enlarged slope efficiency. Numerical simulation results also suggest that the improved laser output performances are due mainly to the reduction of electron leakage current and the enhanced hole injection efficiency in the multiple-quantum-well (MQW) active region.

  3. Ion gyro-harmonic structuring in the stimulated radiation spectrum and optical emissions during electron gyro-harmonic heating

    Science.gov (United States)

    Mahmoudian, A.; Scales, W. A.; Bernhardt, P. A.; Samimi, A.; Kendall, E.; Ruohoniemi, J. M.; Isham, B.; Vega-Cancel, O.; Bordikar, M.

    2013-03-01

    Stimulated electromagnetic emissions (SEEs) are secondary radiation produced during active space experiments in which the ionosphere is actively heated with high power high frequency (HF) ground-based radio transmitters. Recently, there has been significant interest in ion gyro-harmonic structuring the SEE spectrum due to the potential for new diagnostic information available such as electron acceleration and creation of artificial ionization layers. These relatively recently discovered gyro-harmonic spectral features have almost exclusively been studied when the transmitting frequency is near the second electron gyro-harmonic frequency. The first extensive systematic experimental investigations of the possibility of these spectral features for third electron gyro-harmonic heating are provided here. Discrete spectral features shifted from the transmit frequency ordered by harmonics of the ion gyro-frequency were observed for third electron gyro-harmonic heating for the first time at a recent campaign at the High Frequency Active Auroral Research Program (HAARP) facility. These features were also closely correlated with a broader band feature at a larger frequency shift from the transmit frequency known as the downshifted peak (DP). The power threshold of these spectral features was measured, as well as their behavior with heater beam angle, and proximity of the transmit frequency to the third electron gyro-harmonic frequency. Comparisons were also made with similar spectral features observed during second electron gyro-harmonic heating during the same campaign. A theoretical model is provided that interprets these spectral features as resulting from parametric decay instabilities in which the pump field ultimately decays into high frequency upper hybrid/electron Bernstein and low frequency neutralized ion Bernstein IB and/or obliquely propagating ion acoustic waves at the upper hybrid interaction altitude. Coordinated optical and SEE observations were carried out

  4. Quantum Geometry: Relativistic energy approach to cooperative electron-nucleary-transition spectrum

    Directory of Open Access Journals (Sweden)

    Ольга Юрьевна Хецелиус

    2014-11-01

    Full Text Available An advanced relativistic energy approach is presented and applied to calculating parameters of electron-nuclear 7-transition spectra of nucleus in the atom. The intensities of the spectral satellites are defined in the relativistic version of the energy approach (S-matrix formalism, and gauge-invariant quantum-electrodynamical perturbation theory with the Dirac-Kohn-Sham density-functional zeroth approximation.

  5. Ab initio study of the electronic spectrum of BeO

    Directory of Open Access Journals (Sweden)

    MILJENKO PERIC

    1999-12-01

    Full Text Available Low-lying singlet and triplet electronic states of the BeO molecule are calculated by means of the quantum chemical ab initio method. It was found that all states in the energy range from 0 to 50000 cm-1 are of valence character. Particular attention was paid to the investigation of the dissociative behavior of the states considered. The vibrational structure of the AIP<-XIS and BIS+<-XIS+ spectral systems was calculated.

  6. Exact non-Markovian two-time correlation functions and current noise spectrum of electron transport through a quantum dot

    Science.gov (United States)

    Jian, Chung-Chin; Goan, Hsi-Sheng

    2014-03-01

    Two-time correlation functions (CF's) of the electric currents through nanostructure devices are important in the study of the transport properties of current fluctuations and noise spectra. In the Markovian case, an extremely useful procedure to calculate the two-time (multiple-time) CF's is the so-called quantum regression theorem (QRT). For transport problems, a widely used method to calculate the steady-state current noise spectrum (i.e., Fourier transform of the steady-state current-current two-time CF's) is the MacDonald's formula which can be shown to be equivalent to QRT. However, similar to the QRT where only the evolution equations of the single-time expectation values are required to evaluate two-time CF's, the MacDonald's formula involves also only the single-time expectation values. Thus the MacDonald's formula, in our opinion, may not be applicable to calculate the current noise spectrum for transport problems that involves processes with non-Markovian (memory) effects. Here we develop a correct method to calculate the non-Markovian two-time CF's and finite-frequency noise power spectra based on the approach of the non-Markovian quantum state diffusion (NMQSD) or diffusive stochastic Schrodinger equation. This powerful NMQSD method allows us to calculate the exact current-current two-time CF and thus the exact current noise power spectrum for electron transport through a quantum dot. Our exact results reduce to those obtained by QRT or the MacDonald's formula in the Markovian limit.

  7. Effect of the launched LH spectrum on the fast electron dynamics in the plasma core and edge

    Energy Technology Data Exchange (ETDEWEB)

    Goniche, M.; Ekedahl, A.; Laugier, J.; Peysson, Y. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France); Petrz Ilka, V.; Fuchs, V.; Zaeek, F. [Association Euratom / IPP.CR, Czech Academy of Sciences, Praha (Czech Republic)

    2003-07-01

    The lower hybrid current drive efficiency in the Tore Supra tokamak was investigated in various cases of launched N{sub /} spectra. By varying the number of energized waveguides, the broadening of the N{sub /} spectrum is varied by a factor 3.5. Weak effect of this broadening is found. The effect of the central value N{sub /0} and the MHD activity is also documented. The parasitic losses of fast electrons in the scrape-off layer are analyzed from infra-red images of the antenna protection limiter. For these experiments performed at constant LH power, the heat flux scales mainly with the RF electric field. The effect of the number of powered waveguides is discussed. (authors)

  8. H_2 fluorescence spectrum from 1200 to 1700 Å by electron impact: Laboratory study and application to Jovian aurora

    OpenAIRE

    Yung, Yuk L.; Gladstone, G. Randall; Chang, Kar Man; Ajello, Joseph M.; Srivastava, S K

    1982-01-01

    A combined experimental study of the fluorescence spectrum of H_2 at wavelengths of 1200-1700 Å by electron impact and its application to modeling the Jovian aurora have been carried out. Our laboratory data suggest that at 100 eV the relative cross sections for direct excitation of Lyɑ, Lyman bands (B^1Σ_u^+-X^1Σ_g^+), and Werner bands (C^1π_u-X^1Σ_g^+) are 1, 2.3±0.6, and 2.6±0.5, respectively, in conflict with Stone and Zipfs (1972) results for the Werner bands. Cascade from E,F^1Σ_g^+ ...

  9. Superposed epoch analysis of vertical ion velocity, electron temperature, field-aligned current, and thermospheric wind in the dayside auroral region as observed by DMSP and CHAMP

    Science.gov (United States)

    Kervalishvili, G.; Lühr, H.

    2016-12-01

    This study reports on the results obtained by a superposed epoch analysis (SEA) method applied to the electron temperature, vertical ion velocity, field-aligned current (FAC), and thermospheric zonal wind velocity at high-latitudes in the Northern Hemisphere. The SEA study is performed in a magnetic latitude versus magnetic local time (MLat-MLT) frame. The obtained results are based on observations collected during the years 2001-2005 by the CHAMP and DMSP (F13 and F15) satellites. The dependence on interplanetary magnetic field (IMF) orientations is also investigated using data from the NASA/GSFC's OMNI database. Further, the obtained results are subdivided into three Lloyd seasons of 130 days each, which are defined as follows: local winter (1 January ± 65 days), combined equinoxes (1 April and 1 October ± 32days), and local summer (1 July ± 65 days). A period of 130 days is needed by the CHAMP satellite to pass through all local times. The time and location of the electron temperature peaks from CHAMP measurements near the cusp region are used as the reference parameter for the SEA method to investigate the relationship between the electron temperature and other ionospheric quantities. The SEA derived MLat profiles of the electron temperature show a seasonal dependence, increasing from winter to summer, as expected. But, the temperature rise (difference between the reference temperature peak and the background electron temperature) strongly decreases towards local summer. The SEA derived MLat profiles of the ion vertical velocity at DMSP altitude show the same seasonal behaviour as the electron temperature rice. There exists a clear linear relation between these two variables with a quiet large correlation coefficient value, >0.9. The SEA derived MLat profiles of both, thermospheric zonal wind velocity and FAC, show a clear IMF By orientation dependence for all local seasons. The zonal wind velocity is prominently directed towards west in the MLat-MLT frame

  10. Bedtime Electronic Media Use and Sleep in Children with Autism Spectrum Disorder.

    Science.gov (United States)

    Mazurek, Micah O; Engelhardt, Christopher R; Hilgard, Joseph; Sohl, Kristin

    2016-09-01

    The purpose of this study was to better understand the use of screen-based media at bedtime among children with autism spectrum disorder (ASD). The study specifically examined whether the presence of media devices in the child's bedroom, the use of media as part of the bedtime routine, and exposure to media with violent content just before bedtime were associated with sleep difficulties. Parents of 101 children with ASD completed questionnaires assessing their children's sleep habits, bedroom media access (including television, video game devices, and computers), and patterns of nighttime media use (including timing of media exposure and violent media content). Children with ASD who used media as part of the bedtime routine showed significantly greater sleep onset latency than those who did not (39.8 vs 16.0 minutes). Similarly, children who were exposed to media with violent content within the 30-minute period before bedtime experienced significantly greater sleep onset delays and shorter overall sleep duration. In contrast, the mere presence of bedroom media was not associated with either sleep onset latency or sleep duration. Overall, these findings indicate that incorporating television and video games into the bedtime routine is associated with sleep onset difficulties among children with ASD. Exposure to violent media before bed is also associated with poor sleep. Families of children with ASD should be encouraged to regulate and monitor the timing and content of television and video game use, whether or not such devices are physically present in the child's bedroom.

  11. Engineering the interface characteristics on the enhancement of field electron emission properties of vertically aligned hexagonal boron nitride nanowalls

    Energy Technology Data Exchange (ETDEWEB)

    Sankaran, K.J.; Hoang, D.Q.; Drijkoningen, S.; Pobedinskas, P.; Haenen, K. [Institute for Materials Research (IMO), Hasselt University, Diepenbeek (Belgium); IMOMEC, IMEC vzw, Diepenbeek (Belgium); Srinivasu, K.; Leou, K.C. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu (China); Korneychuk, S.; Turner, S.; Verbeeck, J. [Electron Microscopy for Materials Science (EMAT), University of Antwerp (Belgium); Lin, I.N. [Department of Physics, Tamkang University, Tamsui (China)

    2016-10-15

    Utilization of Au and nanocrystalline diamond (NCD) as interlayers noticeably modifies the microstructure and field electron emission (FEE) properties of hexagonal boron nitride nanowalls (hBNNWs) grown on Si substrates. The FEE properties of hBNNWs on Au could be turned on at a low turn-on field of 14.3 V μm{sup -1}, attaining FEE current density of 2.58 mA cm{sup -2} and life-time stability of 105 min. Transmission electron microscopy reveals that the Au-interlayer nucleates the hBN directly, preventing the formation of amorphous boron nitride (aBN) in the interface, resulting in enhanced FEE properties. But Au forms as droplets on the Si substrate forming again aBN at the interface. Conversely, hBNNWs on NCD shows superior in life-time stability of 287 min although it possesses inferior FEE properties in terms of larger turn-on field and lower FEE current density as compared to that of hBNNWs-Au. The uniform and continuous NCD film on Si also circumvents the formation of aBN phases and allows hBN to grow directly on NCD. Incorporation of carbon in hBNNWs from the NCD-interlayer improves the conductivity of hBNNWs, which assists in transporting the electrons efficiently from NCD to hBNNWs that results in better field emission of electrons with high life-time stability. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Coherent vertical electron transport and interface roughness effects in AlGaN/GaN intersubband devices

    Science.gov (United States)

    Grier, A.; Valavanis, A.; Edmunds, C.; Shao, J.; Cooper, J. D.; Gardner, G.; Manfra, M. J.; Malis, O.; Indjin, D.; Ikonić, Z.; Harrison, P.

    2015-12-01

    We investigate electron transport in epitaxially grown nitride-based resonant tunneling diodes (RTDs) and superlattice sequential tunneling devices. A density-matrix model is developed, and shown to reproduce the experimentally measured features of the current-voltage curves, with its dephasing terms calculated from semi-classical scattering rates. Lifetime broadening effects are shown to have a significant influence in the experimental data. Additionally, it is shown that the interface roughness geometry has a large effect on current magnitude, peak-to-valley ratios and misalignment features; in some cases eliminating negative differential resistance entirely in RTDs. Sequential tunneling device characteristics are dominated by a parasitic current that is most likely to be caused by dislocations; however, excellent agreement between the simulated and experimentally measured tunneling current magnitude and alignment bias is demonstrated. This analysis of the effects of scattering lifetimes, contact doping and growth quality on electron transport highlights critical optimization parameters for the development of III-nitride unipolar electronic and optoelectronic devices.

  13. Performance in the vertical test of the 832 nine-cell 1.3 GHz cavities for the European X-ray Free Electron Laser

    Science.gov (United States)

    Reschke, D.; Gubarev, V.; Schaffran, J.; Steder, L.; Walker, N.; Wenskat, M.; Monaco, L.

    2017-04-01

    The successful production and associated vertical testing of over 800 superconducting 1.3 GHz accelerating cavities for the European X-ray Free Electron Laser (XFEL) represents the culmination of over 20 years of superconducting radio-frequency R&D. The cavity production took place at two industrial vendors under the shared responsibility of INFN Milano-LASA and DESY. Average vertical testing rates at DESY exceeded 10 cavities per week, peaking at up to 15 cavities per week. The cavities sent for cryomodule assembly at Commissariat à l'énergie atomique (CEA) Saclay achieved an average maximum gradient of approximately 33 MV /m , reducing to ˜30 MV /m when the operational specifications on quality factor (Q) and field emission were included (the so-called usable gradient). Only 16% of the cavities required an additional surface retreatment to recover their low performance (usable gradient less than 20 MV /m ). These cavities were predominantly limited by excessive field emission for which a simple high pressure water rinse (HPR) was sufficient. Approximately 16% of the cavities also received an additional HPR, e.g. due to vacuum problems before or during the tests or other reasons, but these were not directly related to gradient performance. The in-depth statistical analyses presented in this report have revealed several features of the series produced cavities.

  14. Performance in the vertical test of the 832 nine-cell 1.3 GHz cavities for the European X-ray Free Electron Laser

    Directory of Open Access Journals (Sweden)

    D. Reschke

    2017-04-01

    Full Text Available The successful production and associated vertical testing of over 800 superconducting 1.3 GHz accelerating cavities for the European X-ray Free Electron Laser (XFEL represents the culmination of over 20 years of superconducting radio-frequency R&D. The cavity production took place at two industrial vendors under the shared responsibility of INFN Milano–LASA and DESY. Average vertical testing rates at DESY exceeded 10 cavities per week, peaking at up to 15 cavities per week. The cavities sent for cryomodule assembly at Commissariat à l’énergie atomique (CEA Saclay achieved an average maximum gradient of approximately 33  MV/m, reducing to ∼30  MV/m when the operational specifications on quality factor (Q and field emission were included (the so-called usable gradient. Only 16% of the cavities required an additional surface retreatment to recover their low performance (usable gradient less than 20  MV/m. These cavities were predominantly limited by excessive field emission for which a simple high pressure water rinse (HPR was sufficient. Approximately 16% of the cavities also received an additional HPR, e.g. due to vacuum problems before or during the tests or other reasons, but these were not directly related to gradient performance. The in-depth statistical analyses presented in this report have revealed several features of the series produced cavities.

  15. Tuning electronic and optical properties of arsenene/C3N van der Waals heterostructure by vertical strain and external electric field.

    Science.gov (United States)

    Zeng, Hui; Zhao, Jun; Cheng, Ai-Qiang; Zhang, Lei; He, Zi; Chen, Ru-Shan

    2018-02-16

    Searching for new van der Waals (vdW) heterostructure with novel electronic and optical properties is of great interest and importance for the next generation of devices. By using first-principles calculations, we show that the electronic and optical properties of the arsenene/C3N vdW heterostructure can be effectively modulated by applying vertical strain and external electric field. Our results suggest that this heterostructure has an intrinsic type-II band alignment with an indirect bandgap of 0.16 eV, facilitating the separation of photogenerated electron-hole pairs. The bandgap in the heterostructure can be tuned from 0-0.35 eV via the strain, experiencing an indirect-to-direct bandgap transition. Moreover, the bandgap of the heterostructure varies linearly with respect to a moderate external electric field, and the semiconductor-to-metal transition can be realized in the presence of a strong electric field. The calculated band alignment and the optical absorption reveal that the arsenene/C3N heterostructure could present excellent light-harvesting performance. Our designed vdW heterostructure is expected to have great potential applications in nanoelectronic devices and photovoltaics.

  16. Far-infrared cw difference-frequency generation using vertically integrated and planar low temperature grown GaAs photomixers: application to H2S rotational spectrum up to 3 THz

    Science.gov (United States)

    Mouret, G.; Matton, S.; Bocquet, R.; Hindle, F.; Peytavit, E.; Lampin, J. F.; Lippens, D.

    2004-10-01

    The generation of continuous coherent THz radiation by mixing two cw Ti:Sa laser beams with a well-controlled frequency separation for a new scheme of vertically integrated low temperature grown GaAs (LTG-GaAs) spiral photomixer is reported. For this new photomixer device used in THz emission, the LTG-GaAs active layer is sandwiched between the two parallel metal plates of a high-speed photodetector loaded by a broadband spiral antenna. We have exploited the advantage of a higher delivered power in the low part of the spectrum (detector was used at the upper frequency. The performances of the spectroscopic setup in terms of spectral resolution (5 MHz), tunability and frequency capability are assessed by measurements of the pure rotational spectra of hydrogen sulfide (H2S) up to 3000 GHz.

  17. An experimental and theoretical study of the electronic spectrum of the HBCl free radical

    Energy Technology Data Exchange (ETDEWEB)

    Gharaibeh, Mohammed A. [Department of Chemistry, The University of Jordan, Amman 11942 (Jordan); Nagarajan, Ramya; Clouthier, Dennis J., E-mail: dclaser@uky.edu [Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Tarroni, Riccardo [Dipartimento di Chimica Industriale “Toso Montanari,” Università di Bologna, Viale Risorgimento 4, 40136 Bologna (Italy)

    2015-01-07

    Following our previous discovery of the spectra of the HBX (X = F, Cl, and Br) free radicals [S.-G. He, F. X. Sunahori, and D. J. Clouthier, J. Am. Chem. Soc. 127, 10814 (2005)], the A{sup ~2}A{sup ″}Π−X{sup ~2}A{sup ′} band systems of the HBCl and DBCl free radicals have been studied in detail. The radicals have been prepared in a pulsed electric discharge jet using a precursor mixture of BCl{sub 3} and H{sub 2} or D{sub 2} in high pressure argon. Laser-induced fluorescence (LIF) and single vibronic level emission spectra have been recorded to map out the ground and excited state vibrational energy levels. The band system involves a linear-bent transition between the two Renner-Teller components of what would be a {sup 2}Π electronic state at linearity. We have used high level ab initio theory to calculate the ground and excited state potential energy surfaces and have determined the vibronic energy levels variationally. The theory results were used to assign the LIF spectra which involve transitions from the ground state zero-point level to high vibrational levels of the excited state. The correspondence between theory and experiment, including the transition frequencies, upper state band symmetries, and H, B, and Cl isotope shifts, was used to validate the assignments.

  18. Determination of the electron-antineutrino correlation coefficient a in neutron beta-decay by measurement of the integrated proton spectrum

    CERN Document Server

    Dawber, P G; Grinten, M G D; Habeck, C; Shaikh, F; Spain, J A; Baker, C A; Green, K; Scott, R D; Zimmer, O

    2000-01-01

    The principle is discussed and some preliminary results are given of an experiment in progress at ILL, which aims to determine the electron-antineutrino correlation coefficient, a, from a measurement of the integrated proton energy spectrum following neutron decay in an electromagnetic trap.

  19. The electronic spectrum of CUONg(4) (Ng = Ne, Ar, Kr, Xe): New insights in the interaction of the CUO molecule with noble gas matrices

    NARCIS (Netherlands)

    Tecmer, P.; van Lingen, H.; Gomes, A.S.P.; Visscher, L.

    2012-01-01

    The electronic spectrum of the CUO molecule was investigated with the IHFSCC-SD (intermediate Hamiltonian Fock-space coupled cluster with singles and doubles) method and with TD-DFT (time-dependent density functional theory) employing the PBE and PBE0 exchange-correlation functionals. The importance

  20. Tuning electronic and optical properties of arsenene/C3N van der Waals heterostructure by vertical strain and external electric field

    Science.gov (United States)

    Zeng, Hui; Zhao, Jun; Cheng, Ai-Qiang; Zhang, Lei; He, Zi; Chen, Ru-Shan

    2018-02-01

    Searching for new van der Waals (vdW) heterostructure with novel electronic and optical properties is of great interest and importance for the next generation of devices. By using first-principles calculations, we show that the electronic and optical properties of the arsenene/C3N vdW heterostructure can be effectively modulated by applying vertical strain and external electric field. Our results suggest that this heterostructure has an intrinsic type-II band alignment with an indirect bandgap of 0.16 eV, facilitating the separation of photogenerated electron–hole pairs. The bandgap in the heterostructure can be tuned from 0–0.35 eV via the strain, experiencing an indirect-to-direct bandgap transition. Moreover, the bandgap of the heterostructure varies linearly with respect to a moderate external electric field, and the semiconductor-to-metal transition can be realized in the presence of a strong electric field. The calculated band alignment and the optical absorption reveal that the arsenene/C3N heterostructure could present excellent light-harvesting performance. Our designed vdW heterostructure is expected to have great potential applications in nanoelectronic devices and photovoltaics.

  1. The development of a new edition of the gamma-ray spectrum catalogues designed for presentation in electronic format

    Energy Technology Data Exchange (ETDEWEB)

    Heath, R.L. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1997-11-01

    New editions of the original Gamma-ray Spectrum Catalogues are being prepared for publication in electronic format. The objective of this program is to produce versions of the Catalogues in CD-ROM format and as an Internet resource. Additions to the original content of the Catalogues will include integrated decay scheme drawings, tables of related decay data, and updated text on the techniques of gamma-ray spectrometry. Related decay data from the Evaluated Nuclear Structure Data File (ENSDF) are then added, and all data converted to the Adobe Acrobat (PDF) format for CD-ROM production and availability on the large-volume Ge detectors, alpha-particle spectra, prompt neutron capture and inelastic scattering gamma-ray spectra, and gross fission product spectra characteristic of fuel cycle waste materials. Characterization of radioactivity in materials is a requirement in many phases of radioactive waste management. Movement, shipping, treatment, all activities which involve handling of mixed waste or TRU categories of waste at all DOE sites will require that measurements and assessment documentation utilize basic nuclear data which are tracable to internationally accepted standard values. This program will involve the identification of data needs unique to the development and application of specialized detector systems for radioactive waste characterization. 8 refs., 8 figs.

  2. Effects of supported electronic text and explicit instruction on science comprehension by students with autism spectrum disorder

    Science.gov (United States)

    Knight, Victoria Floyd

    Supported electronic text (eText), or text that has been altered to increase access and provide support to learners, may promote comprehension of science content for students with disabilities. According to CAST, Book Builder(TM) uses supported eText to promote reading for meaning for all students. Although little research has been conducted in the area of supported eText for students with autism spectrum disorders (ASD), technology (e.g., computer assisted instruction) has been used for over 35 years to instruct students with ASD in academic areas. The purpose of this study was to evaluate the effects of a supported eText and explicit instruction on the science vocabulary and comprehension of four middle school students with ASD. Researchers used a multiple probe across participants design to evaluate the Book Builder (TM) program on measures of vocabulary, literal comprehension, and application questions. Results indicated a functional relation between the Book Builder(TM) and explicit instruction (i.e., model-lead-test, examples and non-examples, and referral to the definition) and the number of correct responses on the probe. In addition, students were able to generalize concepts to untrained exemplars. Finally, teachers and students validate the program as practical and useful.

  3. Measurement and theoretical characterization of electronic absorption spectrum of neutral chrysene (C18H12)and its positive ion in H3BO3 matrix.

    Science.gov (United States)

    Husain, Mudassir M

    2007-09-01

    The ultraviolet and visible spectrum of chrysene and its radical cation formed by ultraviolet irradiation were measured in boric acid glass at room temperature. The theoretical electronic absorption spectrum of any polycyclic aromatic hydrocarbon (PAH) in boric acid matrix is calculated for the first time using semi empirical methods. Earlier reported theoretical results of electronic spectrum are calculated in free state and the results are compared with the spectrum of aromatic systems in glassy or other matrices. The interaction between the trapped PAHs (neutral and ions) and its environment induces strong perturbations of the energy levels which results in large shifts of the electronic transitions as compared to the ideal case of a free, isolated PAH molecule. This shifting due to perturbation has largely been ignored in earlier calculations, while comparing the calculations with the experimentally measured spectrum, in other matrices. The spectrum of singlet and doublet state of chrysene are computed in aqueous medium and also in free state to estimate the spectral shift. Several other geometric (bond length and bond angles) and spectroscopic parameters of chrysene like difference of HOMO-LUMO, ionization potential, dipole moment and polarizability are calculated using semi empirical methods, namely Austin Model 1 (AM1) and Parametric Method 3 (PM3). To get an idea about how the symmetry of chrysene molecule varies upon ionization, the mean polarizability (alpha) as well as its tensor components alpha(xx), alpha(yy) and alpha(zz) are calculated within a field of 0.005 a.u. The lasing action in neutral chrysene and in its cationic form is also discussed for the first time.

  4. Addressing dental fear in children with autism spectrum disorders: a randomized controlled pilot study using electronic screen media.

    Science.gov (United States)

    Isong, Inyang A; Rao, Sowmya R; Holifield, Chloe; Iannuzzi, Dorothea; Hanson, Ellen; Ware, Janice; Nelson, Linda P

    2014-03-01

    Dental care is a significant unmet health care need for children with autism spectrum disorders (ASD). Many children with ASD do not receive dental care because of fear associated with dental procedures; oftentimes they require general anesthesia for regular dental procedures, placing them at risk of associated complications. Many children with ASD have a strong preference for visual stimuli, particularly electronic screen media. The use of visual teaching materials is a fundamental principle in designing educational programs for children with ASD. To determine if an innovative strategy using 2 types of electronic screen media was feasible and beneficial in reducing fear and uncooperative behaviors in children with ASD undergoing dental visits. We conducted a randomized controlled trial at Boston Children's Hospital dental clinic. Eighty (80) children aged 7 to 17 years with a known diagnosis of ASD and history of dental fear were enrolled in the study. Each child completed 2 preventive dental visits that were scheduled 6 months apart (visit 1 and visit 2). After visit 1, subjects were randomly assigned to 1 of 4 groups: (1) group A, control (usual care); (2) group B, treatment (video peer modeling that involved watching a DVD recording of a typically developing child undergoing a dental visit); (3) group C, treatment (video goggles that involved watching a favorite movie during the dental visit using sunglass-style video eyewear); and (4) group D, treatment (video peer modeling plus video goggles). Subjects who refused or were unable to wear the goggles watched the movie using a handheld portable DVD player. During both visits, the subject's level of anxiety and behavior were measured using the Venham Anxiety and Behavior Scales. Analyses of variance and Fisher's exact tests compared baseline characteristics across groups. Using intention to treat approach, repeated measures analyses were employed to test whether the outcomes differed significantly: (1) between

  5. A comparison between state-specific and linear-response formalisms for the calculation of vertical electronic transition energy in solution with the CCSD-PCM method.

    Science.gov (United States)

    Caricato, Marco

    2013-07-28

    The calculation of vertical electronic transition energies of molecular systems in solution with accurate quantum mechanical methods requires the use of approximate and yet reliable models to describe the effect of the solvent on the electronic structure of the solute. The polarizable continuum model (PCM) of solvation represents a computationally efficient way to describe this effect, especially when combined with coupled cluster (CC) methods. Two formalisms are available to compute transition energies within the PCM framework: State-Specific (SS) and Linear-Response (LR). The former provides a more complete account of the solute-solvent polarization in the excited states, while the latter is computationally very efficient (i.e., comparable to gas phase) and transition properties are well defined. In this work, I review the theory for the two formalisms within CC theory with a focus on their computational requirements, and present the first implementation of the LR-PCM formalism with the coupled cluster singles and doubles method (CCSD). Transition energies computed with LR- and SS-CCSD-PCM are presented, as well as a comparison between solvation models in the LR approach. The numerical results show that the two formalisms provide different absolute values of transition energy, but similar relative solvatochromic shifts (from nonpolar to polar solvents). The LR formalism may then be used to explore the solvent effect on multiple states and evaluate transition probabilities, while the SS formalism may be used to refine the description of specific states and for the exploration of excited state potential energy surfaces of solvated systems.

  6. On the role of vertical electron density gradients in the generation of type II irregularities associated with blanketing Es during counter electrojet events - a case study

    Science.gov (United States)

    Devasia, C.; Jyoti, N.; Sridharan, R.; Raghava Reddi, C.; Diwakar, T.; Subba Rao, K.

    The characteristics of different types of Sporadic E (ES) layers and the associated plasma density irregularities over the magnetic equator have been studied in a campaign mode, using VHF backscatter radar, digital ionosonde and ground magnetometer data from Trivandrum (dip lat. 0.5°N, geog. lat. 8.5°N, geog. long. 77°E), India. Blanketing type Es (ESb) with varying intensity and duration were observed in association with afternoon counter electrojet (CEJ). ESb was associated with intense backscatter returns and with either very low zonal electric fields and/or with distortion present in the altitude profile of the phase velocity of the type II irregularities. The results of the coordinator study indicate the possible role of electron density gradients and the role of local winds in their generation, eventually resulting in the ESb layers. Evidences for the local winds to be responsible for the generation of steep vertical gradients based on the VHF backscatter radar data are provided and discussed.

  7. The influence of quaternary electron blocking layer on the performance characteristics of intracavity-contacted oxide-confined InGaN-based vertical cavity surface emitting lasers

    Science.gov (United States)

    Goharrizi, A. Zandi; Alahyarizadeh, Gh.; Hassan, Z.; Hassan, H. Abu

    2015-11-01

    The effect of electron blocking layer (EBL) on the performance characteristics of InGaN-based vertical cavity surface emitting lasers (VCSELs) was numerically investigated using an integrated system engineering technical computer aided design (ISE TCAD) simulation program. Simulation results indicated that the performance characteristics of InGaN quantum well VCSEL were improved by the ternary Al0.17Ga0.83N EBL. Better performance was also obtained when Al0.17Ga0.83N EBL was replaced by a polarization-matched Al0.275In0.115Ga0.61N EBL having the same energy bandgap. The quaternary EBL enhances the output power and differential quantum efficiency (DQE) as well as reduces the threshold current compared with the ternary EBL. Enhancement in the value of the optical intensity was also observed in the VCSEL structure with quaternary EBL. Furthermore, the effect of Al composition of AlInGaN EBL on the performance of InGaN-based VCSEL structure that uses the quaternary AlInGaN EBL was studied. In mole fraction was 0.115, Al mole fraction changed from 0.260 to 0.290 by step 0.005, and optimum performance was achieved in 0.275 Al mole fraction of AlInGaN EBL.

  8. Direct Observation of Ultralow Vertical Emittance using a Vertical Undulator

    Energy Technology Data Exchange (ETDEWEB)

    Wootton, Kent

    2015-09-17

    In recent work, the first quantitative measurements of electron beam vertical emittance using a vertical undulator were presented, with particular emphasis given to ultralow vertical emittances [K. P. Wootton, et al., Phys. Rev. ST Accel. Beams, 17, 112802 (2014)]. Using this apparatus, a geometric vertical emittance of 0.9 ± 0.3 pm rad has been observed. A critical analysis is given of measurement approaches that were attempted, with particular emphasis on systematic and statistical uncertainties. The method used is explained, compared to other techniques and the applicability of these results to other scenarios discussed.

  9. Effect of magnetic field on energy spectrum and localization of electron in CdS/HgS/CdS/HgS/CdS multilayered spherical nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Holovatsky, V.A., E-mail: ktf@chnu.edu.ua; Bernik, I.B.; Yakhnevych, M. Ya.

    2017-03-01

    The theoretical investigation of magnetic field effect on energy spectrum and localization of the electron and oscillator strengths of intraband quantum transitions in the nanostructure CdS/HgS/CdS/HgS/CdS is performed. The calculations are made in the framework of effective mass approximation and rectangular potential barriers model using the method of the expansion of quasi-particle wave functions over the complete basis of functions obtained as the exact solutions of the Schrodinger equation for the electron in the nanostructure without the magnetic field. It is shown that the magnetic field violates the spherical symmetry of the system and takes off the degeneration of energy spectrum with respect to the magnetic quantum number. The energy of the electron in the states with m≥0 increases when magnetic field enhances; for the states with m<0 these dependences are non-monotonous (decreasing at first and then increasing). Moreover, the ground state of electron is formed alternately by the states with m=0, −1, −2, …. Magnetic field influences on the distribution of quasi-particle density. It is shown that the electron significantly changes its localization in the nanostructure with two potential wells tunneling through the potential barrier under the effect of magnetic field, changing the oscillator strengths of intraband quantum transitions.

  10. iPad: Efficacy of Electronic Devices to Help Children with Autism Spectrum Disorder to Communicate in the Classroom

    Science.gov (United States)

    Sankardas, Sulata Ajit; Rajanahally, Jayashree

    2017-01-01

    Children with Autism Spectrum Disorder (ASD) are known to have difficulty in social communication, with research indicating that children with ASD fail to develop functional speech (Lord and Rutter, 1994). Over the years a number of Augmented and Alternate Communication (AAC) devices have been used with children with ASD to overcome this barrier…

  11. Model for the broadband Crab nebula spectrum with injection of a log-parabola electron distribution at the wind termination shock

    Science.gov (United States)

    Fraschetti, F.; Pohl, M.

    2017-10-01

    We develop a model of the steady-state spectrum of the Crab nebula encompassing both the radio/soft X-ray and the GeV/multi-TeV observations. By solving the transport equation for TeV electrons injected at the wind termination shock as a log-parabola momentum distribution and evolved via energy losses, we determine analytically the resulting photon differential energy spectrum. We find an impressive agreement with the observations in the synchrotron region. The predicted synchrotron self-Compton accommodates the previously unsolved origin of the broad 200 GeV peak that matches the Fermi/LAT data beyond 1 GeV with the MAGIC data. A natural interpretation of the deviation from power-law of the photon spectrum customarily fit with empirical broken power-laws is provided. This model can be applied to the radio-to- multi-TeV spectra of a variety of astrophysical outflows, including pulsar wind nebulae and supernova remnants. We also show that MeV-range energetic particle distribution at interplanetary shocks typically fit with broken-power laws or Band function can be accurately reproduced by log-parabolas.

  12. Data correction pre-processing for electronically stored blood culture results: Implications on microbial spectrum and empiric antibiotic therapy

    Directory of Open Access Journals (Sweden)

    Koller Walter

    2009-06-01

    Full Text Available Abstract Background The outcome of patients with bacteraemia is influenced by the initial selection of adequate antimicrobial therapy. The objective of our study was to clarify the influence of different crude data correction methods on a microbial spectrum and ranking of pathogens, and b cumulative antimicrobial susceptibility pattern of blood culture isolates obtained from patients from intensive care units (ICUs using a computer based tool, MONI. Methods Analysis of 13 ICUs over a period of 7 years yielded 1427 microorganisms from positive results. Three different data correction methods were applied. Raw data method (RDM: Data without further correction, including all positive blood culture results. Duplicate-free method (DFM: Correction of raw data for consecutive patient's results yielding same microorganism with similar antibiogram within a two-week period. Contaminant-free method (CFM: Bacteraemia caused by possible contaminants was only assumed as true bloodstream infection, if an organism of the same species was isolated from > 2 sets of blood cultures within 5 days. Results Our study demonstrates that different approaches towards raw data correction – none (RDM, duplicate-free (DFM, and a contaminant-free method (CFM – show different results in analysis of positive blood cultures. Regarding the spectrum of microorganisms, RDM and DFM yielded almost similar results in ranking of microorganisms, whereas using the CFM resulted in a clinically and epidemiologically more plausible spectrum. Conclusion For possible skin contaminants, the proportion of microorganisms in terms of number of episodes is most influenced by the CFM, followed by the DFM. However, with exception of fusidic acid for gram-positive organisms, none of the evaluated correction methods would have changed advice for empiric therapy on the selected ICUs.

  13. Calculated Electronic Behavior and Spectrum of Mg+@C60 Using a Simple Jellium-shell Model

    Directory of Open Access Journals (Sweden)

    H. A. Schuessler

    2004-11-01

    Full Text Available Abstract: We present a method for calculating the energy levels and wave functions of any atom or ion with a single valence electron encapsulated in a Fullerene cage using a jelluim-shell model. The valence electron-core interaction is represented by a one-body pseudo-potential obtained through density functional theory with strikingly accurate parameters for Mg+ and which reduces to a purely Coulombic interaction in the case of H. We find that most energy states are affected little by encapsulation. However, when either the electron in the non-encapsulated species has a high probability of being near the jellium cage, or when the cage induces a maximum electron probability density within it, the energy levels shift considerably. Mg+ shows behavior similar to that of H, but since its wave functions are broader, the changes in its energy levels from encapsulation are slightly more pronounced. Agreement with other computational work as well as experiment is excellent and the method presented here is generalizable to any encapsulated species where a one-body electronic pseudo-potential for the free atom (or ion is available. Results are also presented for off-center hydrogen, where a ground state energy minimum of -14.01 eV is found at a nuclear displacement of around 0.1 Å.

  14. The kinetic energy spectrum of protons produced by the dissociative ionization of H2 by electron impact

    Science.gov (United States)

    Khakoo, M. A.; Srivastava, S. K.

    1985-01-01

    The kinetic energy spectra of protons resulting from the dissociative ionization of H2 by electron impact have been measured for electron impact energies from threshold (approximately 17 eV) to 160 eV at 90 deg and 30 deg detection angles, using a crossed-beam experimental arrangement. To check reliability, two separate proton energy analysis methods have been employed, i.e., a time-of-flight proton energy analysis and an electrostatic hemispherical energy analyzer. The present results are compared with previous measurements.

  15. Determination of the Goos-Hänchen shift in dielectric waveguides via photo emission electron microscopy in the visible spectrum.

    Science.gov (United States)

    Stenmark, Theodore; Word, R C; Könenkamp, R

    2016-02-22

    Photoemission Electron Microscopy (PEEM) is a versatile tool that relies on the photoelectric effect to produce high-resolution images. Pulse lasers allow for multi-photon PEEM where multiple photons are required excite a single electron. This non-linear process can directly image the near field region of electromagnetic fields in materials. We use this ability here to analyze wave propagation in a linear dielectric waveguide with wavelengths of 410 nm and 780 nm. The propagation constant of the waveguide can be extracted from the interference pattern created by the coupled and incident light and shows distinct polarization dependence. The electromagnetic field interaction at the boundaries can then be deduced which is essential to understand power flow in wave guiding structures. These results match well with simulations using finite element techniques.

  16. Measurement of the W Boson Mass with the D0 Run II Detector using the Electron P(T) Spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Andeen, Jr., Timothy R. [Northwestern Univ., Evanston, IL (United States)

    2008-06-01

    This thesis is a description of the measurement of the W boson mass using the D0 Run II detector with 770 pb-1 of p$\\bar{p}$ collision data. These collisions were produced by the Tevatron at √s = 1.96 TeV between 2002 and 2006. We use a sample of W → ev and Z → ee decays to determine the W boson mass with the transverse momentum distribution of the electron and the transverse mass distribution of the boson. We measure MW = 80340 ± 37 (stat.) ± 26 (sys. theo.) ± 51 (sys. exp.) MeV = 80340 ± 68 MeV with the transverse momentum distribution of the electron and MW = 80361 ± 28 (stat.) ± 17 (sys. theo.) ± 51 (sys. exp.) MeV = 80361 ± 61 MeV with the transverse mass distribution.

  17. Research Investigation Directed Toward Extending the Useful Range of the Electromagnetic Spectrum. [atomic spectra and electronic structure of alkali metals

    Science.gov (United States)

    Hartmann, S. R.; Happer, W.

    1974-01-01

    The report discusses completed and proposed research in atomic and molecular physics conducted at the Columbia Radiation Laboratory from July 1972 to June 1973. Central topics described include the atomic spectra and electronic structure of alkali metals and helium, molecular microwave spectroscopy, the resonance physics of photon echoes in some solid state systems (including Raman echoes, superradiance, and two photon absorption), and liquid helium superfluidity.

  18. Ion Gyro-Harmonic Structuring in the Stimulated Electromagnetic Emission Spectrum During Second Electron Gyro-Harmonic Heating

    Science.gov (United States)

    Scales, Wayne; Bernhardt, Paul; Samimi, Alireza; Bricinsky, Stanley; Selcher, Craig

    2012-07-01

    Recent observations of Stimulated Electromagnetic Emissions SEEs have shown structures ordered by the ion gyro-frequency. In particular, during experiments in which the heating frequency is near the second electron gyro-harmonic, unique discrete spectral features separated by the ion gyro-frequency have been observed within about 1 kHz of the pump frequency. On occasion, a broadband spectral feature near 500 Hz is observed that coexists with the ion gyro-harmonic spectral features. Explanations for these spectral features have been based on parametric decay of the pump field into upper hybrid/electron Bernstein and ion Bernstein and oblique ion acoustic waves at the upper hybrid layer. This presentation will first review important characteristics of these ion gyro-harmonic spectral features obtained during some recent experiments at the High Frequency Active Auroral Research HAARP facility. These characteristics are then compared to predications of an analytical model for three-wave parametric decay of the pump field into upper hybrid/electron Bernstein and ion Bernstein and oblique ion acoustic waves. It is shown from the analytical theory that important pump field parameters that influence the spectral characteristics include the angle of the pump field relative the background magnetic field, the frequency of the pump relative to the second gyro-harmonic, and the pump field strength. Two Dimensional Particle-In-Cell simulations are used to investigate aspects of the nonlinear evolution such as irregularity development and field aligned electron heating in more detail. These simulations show favorable comparisons with the analytical theory predications as well as the experimental observations. Finally, possibilities for utilizing the experimentally observed SEE spectra for diagnostic purposes are discussed.

  19. X-ray spectrometry and spectrum image mapping at output count rates above 100 kHz with a silicon drift detector on a scanning electron microscope.

    Science.gov (United States)

    Newbury, Dale E

    2005-01-01

    A third-generation silicon drift detector (SDD) in the form of a silicon multicathode detector (SMCD) was tested as an analytical x-ray spectrometer on a scanning electron microscope. Resolution, output count rate, and spectral quality were examined as a function of the detector peaking time from 8 micros to 250 ns and over a range of input count rate (dead time). The SDD-SMCD (50 mm2 active area) produced a resolution of 134 eV with a peaking time of 8 micros. The peak width and peak channel were nearly independent of the input count rate (at 8 micros peaking time, the peak width degradation was 0.003 eV/percent dead time and peak position change was -0.7 eV over the dead time range tested). Maximum output count rates as high as 280 kHz were obtained with a 500 ns peaking time (188 eV resolution) and 500 kHz with a 250 ns peaking time (217 eV resolution). X-ray spectrum imaging was achieved with a pixel dwell time as short as 10 ms (with 1.3 ms overhead) in which a 2048 channel (10 eV/channel) spectrum with 2-byte intensity range was recorded at each pixel (scanned at 128 x 128). With a 220 kHz output count rate, a minor constituent of iron (present at a concentration of 0.04 mass fraction or 4 weight %) in an aluminum-nickel alloy could be readily detected in the x-ray maps derived from the x-ray spectrum image database accumulated in 185 s.

  20. Atomic and electronic structure of free niobium nanoclusters: Simulation of the M{sub 4,5}-XANES spectrum of Nb{sub 13}{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Kravtsova, Antonina N., E-mail: akravtsova@sfedu.ru [Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge str. 5, 344090 Rostov-on-Don (Russian Federation); Lomachenko, Kirill A. [Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge str. 5, 344090 Rostov-on-Don (Russian Federation); Department of Chemistry and NIS Centre of Excellence, University of Turin, Via P. Giuria 7, 10125 Turin (Italy); Soldatov, Alexander V., E-mail: soldatov@sfedu.ru [Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge str. 5, 344090 Rostov-on-Don (Russian Federation); Meyer, Jennifer; Niedner-Schatteburg, Gereon [Technische Universität Kaiserslautern, Fachbereich Chemie und Forschungszentrum OPTIMAS, Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern (Germany); Peredkov, Sergey [Helmholtz-Zentrum Berlin für Materialien und Energie, Wilhelm-Conrad-Röntgen-Campus Adlershof, Elektronenspeicherring BESSY II, Albert-Einstein-Straße 15, Berlin (Germany); Eberhardt, Wolfgang [Technische Universität Berlin, IOAP, Straße des 17. Juni 135, 10623 Berlin (Germany); Neeb, Matthias, E-mail: matthias.neeb@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie, Wilhelm-Conrad-Röntgen-Campus Adlershof, Elektronenspeicherring BESSY II, Albert-Einstein-Straße 15, Berlin (Germany)

    2014-08-15

    Highlights: • M{sub 4,5}-XANES spectra have been calculated for several structural models of free Nb{sub 13}{sup +} cluster. • Theoretical M{sub 4,5}-XANES have been compared with the experimental spectrum of free Nb{sub 13}{sup +}. • Icosahedral structure of Nb{sub 13}{sup +} shows better agreement with experiment than the “amorphous” one. • Distance between Nb atoms in the icosahedral cluster is distinctly reduced as compared to the bulk phase. - Abstract: The atomic and electronic structure of free niobium nanoclusters has been studied on the basis of X-ray absorption near-edge structure (XANES) spectroscopy and density functional theory. M{sub 4,5}-XANES spectra have been calculated for several structural models of the 13-atomic niobium cluster. The calculations have been done on the basis of both full multiple scattering theory within the muffin-tin approximation for a potential and full-potential finite difference method. The comparison of the experimental M{sub 4,5}-edge XANES spectrum (Peredkov et al., J. Electron Spectros. Relat. Phenomena 184 (2011) 113–118) with the simulated X-ray absorption spectra of Nb{sub 13}{sup +} hints to a highly-symmetric icosahedral structure of the cluster. An internuclear distance of 2.2 ± 0.1 Å between neighboring “surface” atoms of the icosahedron and 2.09 Å between the central “bulk” atom and “surface” atoms, respectively, has been found upon comparison of the experimental and theoretical XANES spectra.

  1. Red shift of the SF6 vibration spectrum induced by the electron absorption: An ab initio study

    Directory of Open Access Journals (Sweden)

    Bin Tang

    2018-01-01

    Full Text Available As a widely used gas insulator, sulfur hexafluoride (SF6 has a large cross section for electron absorption, which may make the molecule ionized to the -1 charge state in the high-voltage environment. Using ab initio calculations, we show that the absorbed electron is located averagely on the six F atoms, occupying the antibonding level of the s-p σ bonds and increasing the S-F bond length. The ionized SF6- molecule decreases its decomposition energy to only 1.5 eV, much lower than that of the neutral molecule (4.8 eV, which can be understood according to the occupying of the antibonding orbital and thus weakening of the s-p σ bonds. The weakening of the bonds results in an obvious red shift in the vibrational modes of the ionized SF6- molecule by 120-270 cm-1, compared to those of the neutral molecule. The detailed origin of these vibrational modes is analyzed. Since the appearance of the ionized SF6- molecules is before the decomposition reaction of the SF6- molecule into low-fluoride sulfides, this method may improve the sensitivity of the defection of the partial discharge and save more time for the prevention of the insulation failure in advance.

  2. Observation of fine structure in auger electron spectra for chemical state analysis. Auger denshi bunko ho ni yoru jotai bunseki no tame no spectrum bisai kozo kansatsu

    Energy Technology Data Exchange (ETDEWEB)

    Hirokawa, K. (Tohoku Univ., Sendai (Japan). Inst. for Materials Research); Fukuda, Y. (Shizuoka Univ., Shizuoka (Japan). Research Inst. of Electronics); Suzuki, K. (Nippon Steel Corp., Tokyo (Japan)); Hashimoto, S. (NKK Corp., Tokyo (Japan)); Suzuki, T. (Kawasaki Steel Corp., Kobe (Japan)); Usuki, N. (Sumotomo Metal Industries, Ltd., Osaka (Japan)); Gennai, N. (Kobelco Research Inst., Inc., Kobe (Japan)); Yoshida, S. (Daido Steel Co. Ltd., Nagoya (Japan)); Koda, M. (Nisshin Steel Co. Ltd., Tokyo (Japan)); Sezaki, H. (Hitachi Metals, Ltd., Tokyo (Japan)); Horie, H. (Kyushu Electronic Metal Co. Ltd., Fukuoka (Japan)); Tanaka, A. (ULVAC-PHI Incorporated, Kanagawa (Japan)); Otsubo, T. (The Japan Iron and Steel Federation, Tokyo (Japan))

    1991-09-01

    Cooperative researches by participation of 8 analytical laboratories such as Institute for Materials Research, Tohoku University and Steel Research Center, NKK Corporation, etc. were conducted wherein the common samples of Au, Fe, Ni, Al and their oxides were measured by means of Auger electron spectra. By virtue of an elastic scattering peak apparatus and the standardization of the sample locations, peak energy values of Auger electron spectra obtained by the respective equipment are neutrally in good agreement. Auger profiles (peak intensity) considerably change according to the respective units and the measuring conditions. When the spectra are as sharp as in LMM, LMV and LVV of Fe, Ni and their oxides, and emerge, as in the case of LMM and LMV, in mutually close energy value, the difference in the ratio of spectrum intensity by the respective machines and measuring methods is small in metal oxides, but, in the case of LVV LMM, the state analysis can be made by its slight change. 10 refs., 9 figs., 1 tab.

  3. Design of high breakdown voltage vertical GaN p-n diodes with high-K/low-K compound dielectric structure for power electronics applications

    Science.gov (United States)

    Du, Jiangfeng; Li, Zhenchao; Liu, Dong; Bai, Zhiyuan; Liu, Yang; Yu, Qi

    2017-11-01

    In this work, a vertical GaN p-n diode with a high-K/low-K compound dielectric structure (GaN CD-VGD) is proposed and designed to achieve a record high breakdown voltage (BV) with a low specific on-resistance (Ron,sp). By introducing compound dielectric structure, the electric field near the p-n junction interface is suppressed due to the effects of high-K passivation layer, and a new electric field peak is induced into the n-type drift region, because of a discontinuity of electrical field at the interface of high-K and low-K layer. Therefore the distribution of electric field in GaN p-n diode becomes more uniform and an enhancement of breakdown voltage can be achieved. Numerical simulations demonstrate that GaN CD-VGD with a BV of 10650 V and a Ron,sp of 14.3 mΩ cm2, resulting in a record high figure-of-merit of 8 GW/cm2.

  4. Electron transport efficiency at opposite leaf sides: effect of vertical distribution of leaf angle, structure, chlorophyll content and species in a forest canopy.

    Science.gov (United States)

    Mänd, Pille; Hallik, Lea; Peñuelas, Josep; Kull, Olevi

    2013-02-01

    We investigated changes in chlorophyll a fluorescence from alternate leaf surfaces to assess the intraleaf light acclimation patterns in combination with natural variations in radiation, leaf angles, leaf mass per area (LMA), chlorophyll content (Chl) and leaf optical parameters. Measurements were conducted on bottom- and top-layer leaves of Tilia cordata Mill. (a shade-tolerant sub-canopy species, sampled at heights of 11 and 16 m) and Populus tremula L. (a light-demanding upper canopy species, sampled at canopy heights of 19 and 26 m). The upper canopy species P. tremula had a six times higher PSII quantum yield (Φ(II)) and ratio of open reaction centres (qP), and a two times higher LMA than T. cordata. These species-specific differences were also present when the leaves of both species were in similar light conditions. Leaf adaxial/abaxial fluorescence ratio was significantly larger in the case of more horizontal leaves. Populus tremula (more vertical leaves), had smaller differences in fluorescence parameters between alternate leaf sides compared with T. cordata (more horizontal leaves). However, optical properties on alternate leaf sides showed a larger difference for P. tremula. Intraspecifically, the measured optical parameters were better correlated with LMA than with leaf Chl. Species-specific differences in leaf anatomy appear to enhance the photosynthetic potential of leaf biochemistry by decreasing the interception of excess light in P. tremula and increasing the light absorptance in T. cordata. Our results indicate that intraleaf light absorption gradient, described here as leaf adaxial/abaxial side ratio of chlorophyll a fluorescence, varies significantly with changes in leaf light environment in a multi-layer multi-species tree canopy. However, this variation cannot be described merely as a simple function of radiation, leaf angle, Chl or LMA, and species-specific differences in light acclimation strategies should also be considered.

  5. H/sub 2/ fluorescence spectrum from 1200 to 1700 A by electron impact: Laboratory study and application to Jovian aurora

    Energy Technology Data Exchange (ETDEWEB)

    Yung, Y.L.; Gladstone, G.R.; Chang, K.M.; Ajello, J.M.; Srivastava, S.K.

    1982-03-15

    A combined experimental study of the fluorescence spectrum of H/sub 2/ at wavelengths of 1200--1700 A by electron impact and its application to modeling the Jovian aurora have been carried out. Our laboratory data suggest that at 100 eV the relative cross sections for direct excitation of Ly..cap alpha.., Lyman bands (B/sup 1/..sigma../sup +//sub u/-X/sup 1/..sigma../sup +//sub g/), and Werner bands (C/sup 1/..pi../sub u/-X/sup 1/..sigma../sup +//sub g/) are 1, 2.3 +- 0.6, and 2.6 +- 0.5, respectively, in conflict with Stone and Zipf's (1972) results for the Werner bands. Cascade from E, F/sup 1/..sigma../sup +//sub g/ states contributes an additional 31% to the B/sup 1/..sigma../sup +//sub u/ state population. It is shown that the most likely fate for the metastable H(2/sup 2/S) atoms produced in the Jovian aurora is collisional quenching to H(2/sup 2/P), and this could add as much as 60% to the predicted Ly..cap alpha.. emission. On the basis of detailed atmospheric and radiative transfer modeling, we conclude that the recent IUE and Voyager observations are consistent with precipitation of electrons with energy in the range of 1--30 keV or other energetic particles that penetrate to number densities of 4 x 10/sup 10/--5 x 10/sup 13/ cm/sup -3/ or column densities of 5 x 10/sup 17/--2 x 10/sup 20/ cm/sup -2/ in the atmosphere. The globally averaged energy flux and production of hydrogen atoms are 0.5--2 ergs cm/sup -2/ and 1--4 x 10/sup 10/ atoms cm/sup -2/ s/sup -1/, respectively.

  6. Determination of the CKM-matrix element |V{sub ub}| from the electron energy spectrum measured in inclusive B→X{sub u}eν decay with the BABAR detector

    Energy Technology Data Exchange (ETDEWEB)

    Lueck, Thomas

    2013-01-30

    This document presents a measurement of the CKM matrix-element vertical stroke V{sub ub} vertical stroke in inclusive semileptonic B→X{sub u}eν events on a dataset of 471 million B anti B events recorded by the BABAR detector. Inclusive B→X{sub u}eν decays are selected by reconstructing a high energetic electron (positron). Background suppression is achieved by selecting events with electron (positron) energies near the kinematical allowed endpoint of B→X{sub u}eν decays. A B→D{sup *}eν veto is applied to further suppress background. This veto uses D{sup *} mesons which have been reconstructed with a partial reconstruction technique.

  7. Acquired vertical accommodative vergence.

    Science.gov (United States)

    Klein-Scharff, Ulrike; Kommerell, Guntram; Lagrèze, Wolf A

    2008-03-08

    Vertical accommodative vergence is an unusual synkinesis in which vertical vergence is modulated together with accommodation. It results from a supranuclear miswiring of the network normally conveying accommodative convergence. So far, it is unknown whether this condition is congenital or acquired. We identified an otherwise healthy girl who gradually developed vertical accommodative vergence between five to 13 years of age. Change of accommodation by 3 diopters induced a vertical vergence of 10 degrees. This observation proves that the miswiring responsible for vertical accommodative vergence must not necessarily be congenital, but can be acquired. The cause and the mechanism leading to vertical accommodative vergence are yet unknown.

  8. Theoretical galactic cosmic ray electron spectrum obtained for sources of varying geometry; Spectre theorique des electrons du rayonnement cosmique dans la galaxie obtenu pour des sources a geometrie variable

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, M.E. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    Jokipii and Meyer have recently obtained an electron density energy spectrum of the cosmic rays, originating in the Galaxy, using integral solutions of the steady state transfer equations, by considering a circular cylindric galactic disc as source and approximating the resulting fourth order integral. In this report, we present general results, obtained by using an arbitrary circular cylindric source, without restricting ourselves to the galactic disc. The integrals are treated exactly. The conclusions of Jokipii and Meyer form special cases of these results. We also obtain an exponential energy variation which, at the moment, is not observed experimentally. The second part of this work deals with more complicated, but perhaps more realistic models of elliptic cylindric and ellipsoidal galactic disc sources. One may also note that a very large source concentrated in a very small region gives a spectrum not unlike that for a small source distributed throughout a large volume. Finally, it may be remarked that the model adopted is much less restrictive than the artificial conception of 'leakage time' followed by other workers. (author) [French] Jokipii et Meyer ont dernierement obtenu un spectre d'energie pour les electrons galactiques dans le rayonnement cosmique, en utilisant les solutions des equations de transfert, a l'etat stationnaire, ces dernieres etant sous forme d'integrales, en prenant une source completement diffusee dans le disque galactique, celui-ci etant hypothetiquement choisi comme circulaire et cylindrique et en faisant une approximation sur l'integrale du quatrieme degre. Dans ce rapport, nous presentons des resultats generaux obtenus en faisant appel a une source, diffusee dans un cylindre circulaire, arbitrairement choisi, c'est-a-dire sans nous restreindre au disque galactique comme source. Les integrales sont traitees d'une maniere exacte. Les conclusions de Jokipii et Meyer constituent des cas speciaux

  9. Spectrum and network measurements

    CERN Document Server

    Witte, Robert A

    2014-01-01

    This new edition of Spectrum and Network Measurements enables readers to understand the basic theory, relate it to measured results, and apply it when creating new designs. This comprehensive treatment of frequency domain measurements successfully consolidates all the pertinent theory into one text. It covers the theory and practice of spectrum and network measurements in electronic systems. It also provides thorough coverage of Fourier analysis, transmission lines, intermodulation distortion, signal-to-noise ratio and S-parameters.

  10. On the vertical structure of longitudinal differences in electron densities in the mid-latitudes: COSMIC radio occultation observations and GITM simulations

    Science.gov (United States)

    Wang, Hui; Liu, Dingwei; Zhang, Kedeng

    2016-04-01

    By using COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) satellite observations, and GITM (Global Ionosphere and Thermosphere Model) simulations, the altitudinal dependences of the longitudinal differences in electron densities Ne were studied at mid-latitudes for the first time. Distinct altitudinal dependences were revealed: (1) in the northern (southern) hemisphere, there were wave-1 variations mainly in the daytime in the altitudes below 180 km, but wave-2 (wave-1) variations over a whole day above 220 km; (2) a transition (or separation) layer occurred mainly in the daytime within 180 km and 220 km, showing reversed longitudinal variation from that at lower altitudes. Solar illumination was one of the plausible mechanisms for the zonal difference of Ne at lower altitudes. At higher altitudes both neutral winds and solar illumination played important roles. The neutral winds effects accounted for the longitudinal differences in Ne in the European-Asian sector. Neutral composition changes and neutral wind effects both contributed to the formation of the transition layer.

  11. Zellweger Spectrum

    Science.gov (United States)

    ... Us Donate The Zellweger Spectrum Zellweger Syndrome, Neonatal Adrenoleukodystrophy (NALD), and Infantile Refsum’s Disease (IRD) The disorders ... of the Zellweger spectrum: Zellweger syndrome (ZS), neonatal adrenoleukodystrophy (NALD), and infantile Refsum disease (IRD). While these ...

  12. Sensing the framework state and guest molecules in MIL-53(Al) via the electron paramagnetic resonance spectrum of V(IV) dopant ions.

    Science.gov (United States)

    Nevjestić, Irena; Depauw, Hannes; Gast, Peter; Tack, Pieter; Deduytsche, Davy; Leus, Karen; Van Landeghem, Melissa; Goovaerts, Etienne; Vincze, Laszlo; Detavernier, Christophe; Van Der Voort, Pascal; Callens, Freddy; Vrielinck, Henk

    2017-09-20

    X-ray diffraction (XRD) and electron paramagnetic resonance spectroscopy (EPR) were combined to study the structural transformations induced by temperature, pressure and air humidity of the "breathing" metal-organic framework (MOF) MIL-53(Al), doped with paramagnetic V(IV) ions, after activation. The correlation between in situ XRD and thermogravimetric analysis measurements showed that upon heating this MOF in air, starting from ambient temperature and pressure, the narrow pore framework first dehydrates and after that makes the transition to a large pore state (lp). The EPR spectra of V(IV)[double bond, length as m-dash]O molecular ions, replacing Al-OH in the structure, also allow to distinguish the as synthesized, hydrated (np-h) and dehydrated narrow pore (np-d), and lp states of MIL-53(Al). A careful analysis of EPR spectra recorded at microwave frequencies between 9.5 and 275 GHz demonstrates that all V(IV)[double bond, length as m-dash]O in the np-d and lp states are equivalent, whereas in the np-h state (at least two) slightly different V(IV)[double bond, length as m-dash]O sites exist. Moreover, the lp MIL-53(Al) framework is accessible to oxygen, leading to a notable broadening of the V(IV)[double bond, length as m-dash]O EPR spectrum at pressures of a few mbar, while such effect is absent for the np-h and np-d states for pressures up to 1 bar.

  13. Vertical axis wind turbines

    Science.gov (United States)

    Krivcov, Vladimir [Miass, RU; Krivospitski, Vladimir [Miass, RU; Maksimov, Vasili [Miass, RU; Halstead, Richard [Rohnert Park, CA; Grahov, Jurij [Miass, RU

    2011-03-08

    A vertical axis wind turbine is described. The wind turbine can include a top ring, a middle ring and a lower ring, wherein a plurality of vertical airfoils are disposed between the rings. For example, three vertical airfoils can be attached between the upper ring and the middle ring. In addition, three more vertical airfoils can be attached between the lower ring and the middle ring. When wind contacts the vertically arranged airfoils the rings begin to spin. By connecting the rings to a center pole which spins an alternator, electricity can be generated from wind.

  14. Variations of the ionospheric parameters and vertical electron density distribution at the northern edge of the EIA from 2010 to 2015 along 95°E and comparison with the IRI-2012

    Science.gov (United States)

    Kalita, Bitap Raj; Bhuyan, Pradip Kumar

    2017-07-01

    The vertical electron density profiles over Dibrugarh (27.5°N, 95°E, 43° dip) a low mid latitude station normally located at the northern edge of the EIA for the period of July 2010 till October 2015 are constructed from the measured bottom side profiles and ionosonde-GPS TEC assisted Topside Sounder Model (TSM) topside profiles. The bottom side density profiles are obtained by using POLAN on the manually scaled ionograms. The topside is constructed by the modified ionosonde assisted TSM model (TaP-TSM assisted by POLAN) which is integrated with POLAN for the first time. The reconstructed vertical profile is compared with the IRI predicted density profile and the electron density profile obtained from the COSMIC/FORMOSAT radio occultation measurements over Dibrugarh. The bottom side density profiles are fitted to the IRI bottom side function to obtain best-fit bottom side thickness parameter B0 and shape parameter B1. The temporal and solar activity variation of the B-parameters over Dibrugarh are investigated and compared to those predicted by IRI-2012 model with ABT-2009 option. The bottom side thickness parameter B0 predicted by the IRI model is found to be similar to the B0 measured over Dibrugarh in the night time and the forenoon hours. Differences are observed in the early morning and the afternoon period. The IRI doesn't reproduce the morning collapse of B0 and overestimates the B0 over Dibrugarh in the afternoon period, particularly in summer and equinox. The IRI model predictions are closest to the measured B0 in the winter of low solar activity. The B0 over Dibrugarh is found to increase by about 15% with solar activity during the period of study encompassing almost the first half of solar cycle 24 but solar activity effect was not observed in the B1 parameter. The topside profile obtained from TaP profiler is thicker than the IRI topside in equinox from afternoon to sunrise period but is similar to the IRI in summer daytime. The differences in the

  15. Subsampling for graph power spectrum estimation

    KAUST Repository

    Chepuri, Sundeep Prabhakar

    2016-10-06

    In this paper we focus on subsampling stationary random signals that reside on the vertices of undirected graphs. Second-order stationary graph signals are obtained by filtering white noise and they admit a well-defined power spectrum. Estimating the graph power spectrum forms a central component of stationary graph signal processing and related inference tasks. We show that by sampling a significantly smaller subset of vertices and using simple least squares, we can reconstruct the power spectrum of the graph signal from the subsampled observations, without any spectral priors. In addition, a near-optimal greedy algorithm is developed to design the subsampling scheme.

  16. Ozone vertical distribution in Mars polar atmosphere

    Science.gov (United States)

    Komitov, B.

    On the basis of an ultraviolet spectrum obtained over the north polar region of Mars by Mariner-9, the vertical profile of the ozone density is calculated. A density maximum is found at about 25 km height over the surface of the planet. Its value is about 1×1010molecules cm-3. The obtained result is compared to the results obtained by other authors.

  17. Regional vertical total electron content (VTEC) modeling together with satellite and receiver differential code biases (DCBs) using semi-parametric multivariate adaptive regression B-splines (SP-BMARS)

    Science.gov (United States)

    Durmaz, Murat; Karslioglu, Mahmut Onur

    2015-04-01

    There are various global and regional methods that have been proposed for the modeling of ionospheric vertical total electron content (VTEC). Global distribution of VTEC is usually modeled by spherical harmonic expansions, while tensor products of compactly supported univariate B-splines can be used for regional modeling. In these empirical parametric models, the coefficients of the basis functions as well as differential code biases (DCBs) of satellites and receivers can be treated as unknown parameters which can be estimated from geometry-free linear combinations of global positioning system observables. In this work we propose a new semi-parametric multivariate adaptive regression B-splines (SP-BMARS) method for the regional modeling of VTEC together with satellite and receiver DCBs, where the parametric part of the model is related to the DCBs as fixed parameters and the non-parametric part adaptively models the spatio-temporal distribution of VTEC. The latter is based on multivariate adaptive regression B-splines which is a non-parametric modeling technique making use of compactly supported B-spline basis functions that are generated from the observations automatically. This algorithm takes advantage of an adaptive scale-by-scale model building strategy that searches for best-fitting B-splines to the data at each scale. The VTEC maps generated from the proposed method are compared numerically and visually with the global ionosphere maps (GIMs) which are provided by the Center for Orbit Determination in Europe (CODE). The VTEC values from SP-BMARS and CODE GIMs are also compared with VTEC values obtained through calibration using local ionospheric model. The estimated satellite and receiver DCBs from the SP-BMARS model are compared with the CODE distributed DCBs. The results show that the SP-BMARS algorithm can be used to estimate satellite and receiver DCBs while adaptively and flexibly modeling the daily regional VTEC.

  18. Rich eight-branch spectrum of the oblique propagating longitudinal waves in partially spin-polarized electron-positron-ion plasmas.

    Science.gov (United States)

    Andreev, Pavel A; Iqbal, Z

    2016-03-01

    We consider the separate spin evolution of electrons and positrons in electron-positron and electron-positron-ion plasmas. We consider the oblique propagating longitudinal waves in these systems. Working in a regime of high-density n(0) ∼ 10(27) cm(-3) and high-magnetic-field B(0)=10(10) G, we report the presence of the spin-electron acoustic waves and their dispersion dependencies. In electron-positron plasmas, similarly to the electron-ion plasmas, we find one spin-electron acoustic wave (SEAW) at the propagation parallel or perpendicular to the external field and two spin-electron acoustic waves at the oblique propagation. At the parallel or perpendicular propagation of the longitudinal waves in electron-positron-ion plasmas, we find four branches: the Langmuir wave, the positron-acoustic wave, and a pair of waves having spin nature, they are the SEAW and the wave discovered in this paper, called the spin-electron-positron acoustic wave (SEPAW). At the oblique propagation we find eight longitudinal waves: the Langmuir wave, the Trivelpiece--Gould wave, a pair of positron-acoustic waves, a pair of SEAWs, and a pair of SEPAWs. Thus, for the first time, we report the existence of the second positron-acoustic wave existing at the oblique propagation and the existence of SEPAWs.

  19. Vertical atlantoaxial dislocation

    OpenAIRE

    Ramaré, S.; Lazennec, J. Y.; Camelot, C.; Saillant, G.; Hansen, S.; Trabelsi, R.

    1999-01-01

    An unusual case of vertical atlantoaxial dislocation without medulla oblongata or spinal cord injury is reported. The pathogenic process suggested occipito-axial dislocation. The case was treated surgically with excellent results on mobility and pain.

  20. Coordination in vertical jumping

    NARCIS (Netherlands)

    Bobbert, Maarten F.; van Ingen Schenau, Gerrit Jan

    1988-01-01

    The present study was designed to investigate for vertical jumping the relationships between muscle actions, movement pattern and jumping achievement. Ten skilled jumpers performed jumps with preparatory countermovement. Ground reaction forces and cinematographic data were recorded. In addition,

  1. Hybrid vertical cavity laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  2. Composition of vertical gardens

    OpenAIRE

    Sandeva, Vaska; Despot, Katerina

    2013-01-01

    Vertical gardens are fully functional gardens in areas where there is less oxygen and space, ideal for residential and urban cities where there is no vegetation; occupy a special place in interiors furniture. The gardens occupy an important aesthetic problem. Aesthetic task in vertical gardens can be achieved by forming sectors of identification in the urban landscape through the choice of a particular plant spatial composition and composition, to create comfort and representation in commu...

  3. VERTICAL ACTIVITY ESTIMATION USING 2D RADAR

    African Journals Online (AJOL)

    hennie

    1 D. E. Manolakis. Efficient solution and performance analysis of 3-d position estimation by trilateration. IEEE Transactions on Aerospace and Electronic Systems, volume 32(4), pages 1239–1248, October 1996. 2 D. E. Manolakis. Aircraft vertical profile prediction based on surveillance data only. IEE Proceedings on Radar, ...

  4. Controlling the growth of vertically aligned single walled carbon nanotubes from ethanol for electrochemical supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Azam, M.A.; Mohamed, M.A.; Shikoh, E.; Fujiwara, A.; Shimoda, T. [Japan Advanced Inst. of Science and Technology, Ishikawa (Japan)

    2010-07-01

    Single-walled carbon nanotubes (SWCNTs) have been proven suitable for use as electrodes in electrochemical capacitors (EC). In this study, alcohol catalytic chemical vapor deposition (ACCVD) was used to grow vertically-aligned SWCNTs (VASWCNTs). An aluminium oxide (Al{sub 2}O{sub 3})-supported cobalt (Co) catalyst and high purity ethanol carbon feedstock was used for the growth process. The Al layer and Co thin films were deposited using an electron beam evaporator. CNT growth was optimized using Si/SiO{sub 2} substrates. An atomic force microscope, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were used to characterize the synthesis of the catalyst nanoparticles and their subsequent growth. Raman spectrum of the samples demonstrated peaks of radial breathing mode (RBM) from 100 to 250 per cm. Results demonstrated that the CNTs were successfully grown on the conducting metal substrate using the ACCVD process. 4 refs.

  5. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  6. Sensitivity analysis of the influence of the medium energy and initial fluence FWHM of electron determining a Bremsstrahlung photon spectrum of a linear accelerator; Analisis de sensibilidad de la influencia de la energia media FWHM de la influencia inicial de electrones en la determinacion de un espectro de fotones Bremsstrahlung de un acelerador lineal

    Energy Technology Data Exchange (ETDEWEB)

    Juste, B.; Miro, R.; Verdu, G.; Diez, S.; Campayo, J. M.

    2012-11-01

    A correct dose calculation in patient under radiotherapy treatments requires and accurate description of the radiation source. The main goal of the present work is to study the effects of initial electron beam characteristics on Monte Carlo calculated absorbed dose distribution for a 6 MeV linac photon beam. To that, we propose a methodology to determine the initial electron fluence before hitting the accelerator target for an Elektra Precis a medical linear accelerator. The method used for the electron radiation source description is based on a Software for Uncertainty and Sensitivity Analysis (SUSA) and Monte Carlo simulations using the MCNP5 transport code. This electron spectrum has been validated by means of comparison of its resulting depth dose curve in a water cube with experimental data being the mean difference below the 1%. (Author)

  7. An Application of the Direct Coulomb Electron Pair Production Process to the Energy Measurement of the "VH-Group" in the "Knee" Region of the "All-Particle" Energy Spectrum

    Science.gov (United States)

    Derrickson, J. H.; Wu, J.; Christl, M. J.; Fountain, W. F.; Parnell, T. A.

    1999-01-01

    The "all-particle" cosmic ray energy spectrum appears to be exhibiting a significant change in the spectral index just above approximately 3000 TeV. This could indicate (1) a change in the propagation of the cosmic rays in the galactic medium, and/or (2) the upper limit of the supernova shock wave acceleration mechanism, and/or (3) a new source of high-energy cosmic rays. Air shower and JACEE data indicate the spectral change is associated with a composition change to a heavier element mixture whereas DICE does not indicate this. A detector concept will be presented that utilizes the energy dependence of the production of direct Coulomb electron-positron pairs by energetic heavy ions. Monte Carlo simulations of a direct electron pair detector consisting of Pb target foils interleaved with planes of 1-mm square scintillating optical fibers will be discussed. The goal is to design a large area, non-saturating instrument to measure the energy spectrum of the individual cosmic ray elements in the "VH-group" for energies greater than 10 TeV/nucleon.

  8. Spectrum war

    DEFF Research Database (Denmark)

    Henten, Anders; Tadayoni, Reza; Windekilde, Iwona Maria

    a conflict in accessing to the valuable spectrum resources allocated to TV broadcast that has been there for many years and which has been intensified in different phases of technological development and the second being an obvious conflict of interest between the different stake holders within the mobile...

  9. Vertically stacked nanocellulose tactile sensor.

    Science.gov (United States)

    Jung, Minhyun; Kim, Kyungkwan; Kim, Bumjin; Lee, Kwang-Jae; Kang, Jae-Wook; Jeon, Sanghun

    2017-11-16

    Paper-based electronic devices are attracting considerable attention, because the paper platform has unique attributes such as flexibility and eco-friendliness. Here we report on what is claimed to be the firstly fully integrated vertically-stacked nanocellulose-based tactile sensor, which is capable of simultaneously sensing temperature and pressure. The pressure and temperature sensors are operated using different principles and are stacked vertically, thereby minimizing the interference effect. For the pressure sensor, which utilizes the piezoresistance principle under pressure, the conducting electrode was inkjet printed on the TEMPO-oxidized-nanocellulose patterned with micro-sized pyramids, and the counter electrode was placed on the nanocellulose film. The pressure sensor has a high sensitivity over a wide range (500 Pa-3 kPa) and a high durability of 10(4) loading/unloading cycles. The temperature sensor combines various materials such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), silver nanoparticles (AgNPs) and carbon nanotubes (CNTs) to form a thermocouple on the upper nanocellulose layer. The thermoelectric-based temperature sensors generate a thermoelectric voltage output of 1.7 mV for a temperature difference of 125 K. Our 5 × 5 tactile sensor arrays show a fast response, negligible interference, and durable sensing performance.

  10. Ab initio calculation of the electronic spectrum of azobenzene dyes and its impact on the design of optical data storage materials

    DEFF Research Database (Denmark)

    Åstrand, Per-Olof; Ramanujam, P.S.; Hvilsted, Søren

    2000-01-01

    Electronic excitation energies of 16 azobenzene dyes have been calculated by ab initio methods within the second-order polarization propagator approximation (SOPPA). Good agreement with expriment is found for the lowest singlet and triplet states for both the trans- and cis-azobenzene molecules......, the experimental singlet π → π* transitions are reproduced for a set of azobenzene dyes with different electron donor and acceptor groups and the correct shifts in excitation energy are obtained for the different substituents. It has also been demonstrated that ab initio methods can be used to determine suitable...... candidates for azo components used in materials for data storage....

  11. Diel vertical migrat..

    African Journals Online (AJOL)

    2002-01-24

    Jan 24, 2002 ... crustacean zooplankton but also in a Wide array of different marine zooplankton groups. (Russell 1927, McLaren 1963). Thus there is no doubt that ..... cooperation during field work and for their fruitful discussion on the draft manuscript. REFERENCES. Bayly lAE 1986 Aspects of diel vertical migration in ...

  12. Vertical market participation

    DEFF Research Database (Denmark)

    Schrader, Alexander; Martin, Stephen

    1998-01-01

    Firms that operate at both levels of vertically related Cournot oligopolies will purchase some input supplies from independent rivals, even though they can produce the good at a lower cost, driving up input price for nonintegrated firms at the final good level. Foreclosure, which avoids this stra...... this strategic behavior, yields better market performance than Cournot beliefs...

  13. Hunting Voronoi vertices

    NARCIS (Netherlands)

    Ferrucci, V.; Overmars, Mark; Rao, A.; Vleugels, J.

    1994-01-01

    Given three objects in the plane, a Voronoi vertex is a point that is equidistant simultaneously from each. In this paper, we consider the problem of computing Voronoi vertices for planar objects of xed but possibly unknown shape; we only require the ability to query the closest point on an object

  14. Vertical shaft windmill

    Science.gov (United States)

    Grana, D. C.; Inge, S. V., Jr. (Inventor)

    1983-01-01

    A vertical shaft has several equally spaced blades mounted. Each blade consists of an inboard section and an outboard section skew hinged to the inboard section. The inboard sections automatically adjust their positions with respect to the fixed inboard sections with changes in velocity of the wind. This windmill design automatically governs the maximum rotational speed of shaft.

  15. Vertical gastroplasty: evolution of vertical banded gastroplasty.

    Science.gov (United States)

    Mason, E E; Doherty, C; Cullen, J J; Scott, D; Rodriguez, E M; Maher, J W

    1998-09-01

    The objective of this paper is to summarize the goals, technical requirements, advantages, and potential risks of gastroplasty for treatment of severe obesity. Gastroplasty is preferred to more complex operations, as it preserves normal digestion and absorption and avoids complications that are peculiar to exclusion operations. The medical literature and a 30-year experience at the University of Iowa Hospitals and Clinics (UIHC) provides an overview of vertical banded gastroplasty (VBG) evolution. Preliminary 10-year results with the VBG technique currently used at UIHC are included. At UIHC the VBG is preferred to other gastroplasties because it provides weight control that extends for at least 10 years and the required objective, intraoperative quality control required for a low rate of reoperation. It is recommended that modifications of the operative technique not be attempted until a surgeon has had experience with the standardized operation--and then only under a carefully designed protocol. Realistic goals for surgery and criteria of success influence the choice of operation and the optimum, lifelong risk/benefit ratio. In conclusion, VBG is a safe, long-term effective operation for severe obesity with advantages over complex operations and more restrictive simple operations.

  16. Energy spectrum of surface electrons over a {sup 3}He – {sup 4}He solution with a spatially non-uniform distribution of the light isotope

    Energy Technology Data Exchange (ETDEWEB)

    Bezsmolnyy, Ya.Yu.; Sokolova, E.S.; Sokolov, S.S. [B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Prospekt Nauky, 61103 Kharkov (Ukraine); Studart, Nelson [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Av. dos Estados, 5001, 09210-580 Santo André, São Paulo (Brazil); Departamento de Física, Universidade Federal de São Carlos, via Washington Luís, km 235, 13565-905 Säo Carlos, São Paulo (Brazil)

    2017-02-15

    The energy gap between the ground and first excited energy levels of surface electrons deposited over a dilute {sup 3}He - {sup 4}He solution is evaluated. Two spatial distributions of {sup 3}He atoms near the free surface solution are considered. One consists of a thin though macroscopic {sup 3}He film and in the other the {sup 3}He concentration varies continuously from the surface inside the liquid. The energy gap is calculated as a function of the parameters of the {sup 3}He spatial distribution for these distributions. It is shown that the energy gap dependence on the distribution parameters allows using measurements of intersubband transitions of the surface electrons to determine the {sup 3}He concentration distribution and, in principle, the nature of the spatial distribution of the light isotope near the surface of the solution.

  17. The e− Spectrum and e+ Spectrum from AMS

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    Precision measurements by AMS on the ISS of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at ∼30 GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index.

  18. Origin of anomalous electronic circular dichroism spectrum of RuPt2(tppz)2Cl2(PF6)4 in acetonitrile.

    Science.gov (United States)

    Yu, Hua-Gen

    2014-07-24

    We report a theoretical study of the structures, energetics, and electronic spectra of the Pt(II)/Ru(II) mixed-metal complex RuPt2(tppz)2Cl2(PF6)4 (tppz = 2,3,5,6-tetra(2-pyridyl)pyrazine) in acetonitrile. The hybrid B3LYP density functional theory and its TDDFT methods were used with a complete basis set (CBS) extrapolation scheme and a conductor polarizable continuum model (C-PCM) for solvation effects. Results showed that the trinuclear complex has four types of stable conformers and/or enantiomers. They are separated by high barriers owing to the repulsive H/H geometrical constraints in tppz. A strong entropy effect was found for the dissociation of RuPt2(tppz)2Cl2(PF6)n in acetonitrile. The UV-visible and emission spectra of the complex were also simulated. They are in good agreement with experiments. In this work we have largely focused on exploring the origin of anomalous electronic circular dichroism (ECD) spectra of the RuPt2(tppz)2Cl2(PF6)4 complex in acetonitrile. As a result, a new mechanism has been proposed together with a clear illustration by using a physical model.

  19. Therapeutic electrons bunch energy spectrums: correlation among physical parameters and quality; Espectros de energia de feixe de eletrons terapeuticos: correlacao entre parametros fisicos e qualidade

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Rolando Fonseca

    1993-07-01

    A new approach was described for clinical and physical parameters used in radiotherapy planning and dosimetry, studying their dependencies on spectral widths. Two different models of clinical linear accelerators were used-Mevatron 74 (UNICAMP) and Mevatron 12 (HC/FMRP/Ribeirao Preto). Mevatron 74 produces beams with nominal energies from 5 up to 12 MeV and Mevatron 12 from 3 up to 11 MeV. It was verified that the values of clinical parameters expected from a semi-empirical theory differ from that obtained experimentally. Such differences are relevant from the point of view of the design of electron accelerators, as well as, of the target clinical results. (author)

  20. Exciton in vertically coupled type II quantum dots in threading magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza-Cantillo, J., E-mail: jhofry@gmail.com [Group of Investigation in Condensed Matter Theory, Universidad del Magdalena, Carrera 32 No 22-08, Santa Marta (Colombia); Universidad de la Guajira, Riohacha (Colombia); Escorcia-Salas, G. Elizabeth, E-mail: elizabethescorcia@gmail.com [Group of Investigation in Condensed Matter Theory, Universidad del Magdalena, Carrera 32 No 22-08, Santa Marta (Colombia); Mikhailov, I.D., E-mail: mikhail2811@gmail.com [Universidad Industrial de Santander, A. A. 678, Bucaramanga (Colombia); Sierra-Ortega, J., E-mail: jsierraortega@gmail.com [Group of Investigation in Condensed Matter Theory, Universidad del Magdalena, Carrera 32 No 22-08, Santa Marta (Colombia)

    2014-11-15

    We analyze the energy spectrum of a neutral exciton confined in a semiconductor heterostructure formed by two vertically coupled axially symmetrical type II quantum dots located close to each other. The electron in the structure is mainly located inside dots tunneling between them while the hole generally is placed in the exterior region close to the symmetry axis. Solutions of the Schrödinger equation are obtained by a variational separation of variables in the adiabatic limit. Numerical results are presented for the energies of bonding and anti-bonding lowest-lying of the exciton states and for the density of states for different InP/GaInP quantum dots' morphologies and the magnetic field strength values.

  1. GPS, su datum vertical.

    Directory of Open Access Journals (Sweden)

    Esteban Dörries

    2016-03-01

    Full Text Available La introducción de la metodología GPS en aplicaciones topográficas y geodésicas pone en notoria evidencia la clásica separación de sistemas de referencia en horizontal y vertical. Con GPS el posicionamiento es tridimensional, pero el concepto de altura difiere del clásico. Si se desea utilizar la información altimétrica debe contemplarse la ondulación del geoide.

  2. All-electron LCAO calculations of the LiF crystal phonon spectrum: Influence of the basis set, the exchange-correlation functional, and the supercell size.

    Science.gov (United States)

    Evarestov, R A; Losev, M V

    2009-12-01

    For the first time the convergence of the phonon frequencies and dispersion curves in terms of the supercell size is studied in ab initio frozen phonon calculations on LiF crystal. Helmann-Feynman forces over atomic displacements are found in all-electron calculations with the localized atomic functions (LCAO) basis using CRYSTAL06 program. The Parlinski-Li-Kawazoe method and FROPHO program are used to calculate the dynamical matrix and phonon frequencies of the supercells. For fcc lattice, it is demonstrated that use of the full supercell space group (including the supercell inner translations) enables to reduce essentially the number of the displacements under consideration. For Hartree-Fock (HF), PBE and hybrid PBE0, B3LYP, and B3PW exchange-correlation functionals the atomic basis set optimization is performed. The supercells up to 216 atoms (3 x 3 x 3 conventional unit cells) are considered. The phonon frequencies using the supercells of different size and shape are compared. For the commensurate with supercell k-points the best agreement of the theoretical results with the experimental data is found for B3PW exchange-correlation functional calculations with the optimized basis set. The phonon frequencies at the most non-commensurate k-points converged for the supercell consisting of 4 x 4 x 4 primitive cells and ensures the accuracy 1-2% in the thermodynamic properties calculated (the Helmholtz free energy, entropy, and heat capacity at the room temperature). (c) 2009 Wiley Periodicals, Inc.

  3. Solution [Cu(amm)]2+ is a strongly solvated square pyramid: a full account of the copper K-edge XAS spectrum within single-electron theory.

    Science.gov (United States)

    Frank, Patrick; Benfatto, Maurizio; Hedman, Britt; Hodgson, Keith O

    2008-05-19

    The solution structure of Cu(II) in 4 M aqueous ammonia, [Cu(amm)](2+), was assessed using copper K-edge extended X-ray absorption fine structure (EXAFS) and Minuit XANes (MXAN) analyses. Tested structures included trigonal planar, planar and D2d -tetragonal, regular and distorted square pyramids, trigonal bipyramids, and Jahn-Teller distorted octahedra. Each approach converged to the same axially elongated square pyramid, 4 x Cu-Neq=2.00+/-0.02 A and 1 x Cu-Nax=2.16+/-0.02 A (EXAFS) or 2.20+/-0.07 A (MXAN), with strongly localized solvation shells. In the MXAN model, four equatorial ammonias averaged 13 degrees below the Cu(II) xy-plane, which was 0.45+/-0.1 A above the mean N4 plane. When the axial ligand equilibrium partial occupancies of about 0.65 ammonia and 0.35 water were included, EXAFS modeling found Cu-Lax distances of 2.16 and 2.31 A, respectively, reproducing the distances found in the crystal structures of [Cu(NH3)5](2+) and [Cu(NH3)4(H2O)](2+). A transverse axially localized solvent molecule was found at 2.8 A (EXAFS) or 3.1 A (MXAN). Six second-shell solvent molecules were also found at about 3.4+/-0.01 (EXAFS) or 3.8+/-0.2 A (MXAN). The structure of Cu(II) in 4 M pH 10 aqueous NH 3 may be notationally described as {[Cu(NH 3)4.62(H2O)0.38](solv)}(2+).6solv, solv=H2O, NH 3. The prominent shoulder and duplexed maximum of the rising K-edge XAS of [Cu(amm)](2+) primarily reflect the durable and well-organized solvation shells, not found around [Cu(H2O)5](2+), rather than two-electron shakedown transitions. Not accounting for solvent scattering thus may confound XAS-based estimates of metal-ligand covalency. [Cu(amm)](2+) continues the dissymmetry previously found for the solution structure of [Cu(H2O)5](2+), again contradicting the rack-bonding theory of blue copper proteins.

  4. Vertical Protocol Composition

    DEFF Research Database (Denmark)

    Groß, Thomas; Mödersheim, Sebastian Alexander

    2011-01-01

    composition, and it is truly commonplace in today’s communication with the diversity of VPNs and secure browser sessions. In fact, it is normal that we have several layers of secure channels: For instance, on top of a VPN-connection, a browser may establish another secure channel (possibly with a different...... end point). Even using the same protocol several times in such a stack of channels is not unusual: An application may very well establish another TLS channel over an established one. We call this selfcomposition. In fact, there is nothing that tells us that all these compositions are sound, i.......e., that the combination cannot introduce attacks that the individual protocols in isolation do not have. In this work, we prove a composability result in the symbolic model that allows for arbitrary vertical composition (including self-composition). It holds for protocols from any suite of channel and application...

  5. Vertical cavity laser

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention provides a vertical cavity laser comprising a grating layer comprising an in-plane grating, the grating layer having a first side and having a second side opposite the first side and comprising a contiguous core grating region having a grating structure, wherein an index......, an index of refraction of the second low-index layer or air being less than 2; and a thickness of the cap layer and a thickness of the grating layer, and a pitch and a duty cycle of the grating structure are selected to obtain a resonance having a free-space resonance wavelength in the interval 300 nm to 3...... microns, the cap layer comprises an active region configured to generate or absorb photons at the free-space resonance wavelength by stimulated emission or absorption when a sufficient forward or reverse bias voltage is applied across the active region, a thickness of the first low-index layer is less...

  6. Application of Prefabricated Vertical Drain in Soil Improvement

    Directory of Open Access Journals (Sweden)

    Tedjakusuma B.

    2012-01-01

    Full Text Available Although the use of Prefabricated Vertical Drain (PVD in soil improvement is not new, this paper is interesting since it gives the full spectrum from preliminary design stage; trial embankment and pilot test to final soil improvement. The final installation of the PVD was based on the soil investigation report and the results of instrumentation monitoring. Finally, using back analysis, vertical and horizontal coefficients of consolidation and compression index can be determined, which can be applied to predict a more accurate prediction of settlement.

  7. Vertical allometry: fact or fiction?

    Science.gov (United States)

    Mahmood, Iftekhar; Boxenbaum, Harold

    2014-04-01

    In pharmacokinetics, vertical allometry is referred to the clearance of a drug when the predicted human clearance is substantially higher than the observed human clearance. Vertical allometry was initially reported for diazepam based on a 33-fold higher human predicted clearance than the observed human clearance. In recent years, it has been found that many other drugs besides diazepam, can be classified as drugs which exhibit vertical allometry. Over the years, many questions regarding vertical allometry have been raised. For example, (1) How to define and identify the vertical allometry? (2) How much difference should be between predicted and observed human clearance values before a drug could be declared 'a drug which follows vertical allometry'? (3) If somehow one can identify vertical allometry from animal data, how this information can be used for reasonably accurate prediction of clearance in humans? This report attempts to answer the aforementioned questions. The concept of vertical allometry at this time remains complex and obscure but with more extensive works one can have better understanding of 'vertical allometry'. Published by Elsevier Inc.

  8. Protected Vertices in Motzkin trees

    OpenAIRE

    Van Duzer, Anthony

    2017-01-01

    In this paper we find recurrence relations for the asymptotic probability a vertex is $k$ protected in all Motzkin trees. We use a similar technique to calculate the probabilities for balanced vertices of rank $k$. From this we calculate upper and lower bounds for the probability a vertex is balanced and upper and lower bounds for the expected rank of balanced vertices.

  9. Improvement of vertical stabilization on KSTAR

    Science.gov (United States)

    Mueller, D.; Bak, J. G.; Boyer, M. D.; Eideitis, N.; Hahn, S. H.; Humphreys, D. A.; Kim, H. S.; Jeon, Y. M.; Lanctot, M.; Walker, M. L.

    2017-10-01

    The successful control of strongly shaped plasmas on the Korea Superconducting Tokamak Advanced Research (KSTAR) device requires active feedback of fast motion of the plasma vertical position by the use of internal normal conducting coils (IVC). This has required new electronics to supply relative flux loop differences, for zp, and voltage loop differences, for dzp/dt, as well as a novel technique (Zfast) to use a high-pass filter, typically 1 Hz, on the error in the signal in the feedback loop. Use of Zfast avoids the potential contention encountered when the internal coil attempts to perform control of the plasma shape which should be controlled by the slower and more powerful superconducting coils. A common problem of this contention is saturation of the IVC and loss of fast vertical control. This is eliminated by proper use of the Zfast. A Ziegler-Nichols relay feedback system was used to fine tune the required feedback gains. The selection of the magnetic sensors, filter time constants, control gains and of the Zfast control strategy which allowed vertically stable operation at a plasma elongation, kappa. of up to 2.16 at li = 1.15 and Betap = 2.4 will be discussed which is beyond the design reference of KSTAR of kappa = 2.0 at li = 1.2 and Betap = 1.9. Work Supported by U.S.D.O.E. Contract No. DE-AC02-09CH11466 and DE-SC0010685 and the KSTAR project.

  10. Trade Liberalisation and Vertical Integration

    DEFF Research Database (Denmark)

    Bache, Peter Arendorf; Laugesen, Anders Rosenstand

    producers face decisions on exporting, vertical integration of intermediate-input production, and whether the intermediate-input production should be offshored to a low-wage country. We find that the fractions of final-good producers that pursue either vertical integration, offshoring, or exporting are all......We build a three-country model of international trade in final goods and intermediate inputs and study the relation between four different types of trade liberalisation and vertical integration. Firms are heterogeneous with respect to both productivity and factor (headquarter) intensity. Final-good...... increasing when intermediate-input trade or final-goods trade is liberalised. Finally, we provide guidance for testing the open-economy property rights theory of the firm using firm-level data and surprisingly show that the relationship between factor (headquarter) intensity and the likelihood of vertical...

  11. Horizontal and Vertical Line Designs.

    Science.gov (United States)

    Johns, Pat

    2003-01-01

    Presents an art lesson in which students learn about the artist Piet Mondrian and create their own abstract artworks. Focuses on geometric shapes using horizontal and vertical lines. Includes background information about the artist. (CMK)

  12. Vertical axis wind turbine airfoil

    Science.gov (United States)

    Krivcov, Vladimir; Krivospitski, Vladimir; Maksimov, Vasili; Halstead, Richard; Grahov, Jurij Vasiljevich

    2012-12-18

    A vertical axis wind turbine airfoil is described. The wind turbine airfoil can include a leading edge, a trailing edge, an upper curved surface, a lower curved surface, and a centerline running between the upper surface and the lower surface and from the leading edge to the trailing edge. The airfoil can be configured so that the distance between the centerline and the upper surface is the same as the distance between the centerline and the lower surface at all points along the length of the airfoil. A plurality of such airfoils can be included in a vertical axis wind turbine. These airfoils can be vertically disposed and can rotate about a vertical axis.

  13. Backward integration, forward integration, and vertical foreclosure

    OpenAIRE

    Spiegel, Yossi

    2013-01-01

    I show that partial vertical integration may either alleviates or exacerbate the concern for vertical foreclosure relative to full vertical integration and I examine its implications for consumer welfare.

  14. Lagrangian temperature and vertical velocity fluctuations due to gravity waves in the lower stratosphere

    Science.gov (United States)

    Podglajen, Aurélien; Hertzog, Albert; Plougonven, Riwal; Legras, Bernard

    2016-04-01

    Wave-induced Lagrangian fluctuations of temperature and vertical velocity in the lower stratosphere are quantified using measurements from superpressure balloons (SPBs). Observations recorded every minute along SPB flights allow the whole gravity wave spectrum to be described and provide unprecedented information on both the intrinsic frequency spectrum and the probability distribution function of wave fluctuations. The data set has been collected during two campaigns coordinated by the French Space Agency in 2010, involving 19 balloons over Antarctica and 3 in the deep tropics. In both regions, the vertical velocity distributions depart significantly from a Gaussian behavior. Knowledge on such wave fluctuations is essential for modeling microphysical processes along Lagrangian trajectories. We propose a new simple parameterization that reproduces both the non-Gaussian distribution of vertical velocities (or heating/cooling rates) and their observed intrinsic frequency spectrum.

  15. Vertical Motions of Oceanic Volcanoes

    Science.gov (United States)

    Clague, D. A.; Moore, J. G.

    2006-12-01

    lasting a few hundred thousand years as the island migrates over a broad flexural arch related to isostatic compensation of a nearby active volcano. The arch is located about 190±30 km away from the center of volcanic activity and is also related to the rejuvenated volcanic stage on the islands. Reefs on Oahu that are uplifted several tens of m above sea level are the primary evidence for uplift as the islands over-ride the flexural arch. At the other end of the movement spectrum, both in terms of magnitude and length of response, are the rapid uplift and subsidence that occurs as magma is accumulated within or erupted from active submarine volcanoes. These changes are measured in days to years and are of cm to m variation; they are measured using leveling surveys, tiltmeters, EDM and GPS above sea level and pressure gauges and tiltmeters below sea level. Other acoustic techniques to measure such vertical movement are under development. Elsewhere, evidence for subsidence of volcanoes is also widespread, ranging from shallow water carbonates on drowned Cretaceous guyots, to mapped shoreline features, to the presence of subaerially-erupted (degassed) lavas on now submerged volcanoes. Evidence for uplift is more limited, but includes makatea islands with uplifted coral reefs surrounding low volcanic islands. These are formed due to flexural uplift associated with isostatic loading of nearby islands or seamounts. In sum, oceanic volcanoes display a long history of subsidence, rapid at first and then slow, sometimes punctuated by brief periods of uplift due to lithospheric loading by subsequently formed nearby volcanoes.

  16. Integration of photoactive and electroactive components with vertical cavity surface emitting lasers

    Science.gov (United States)

    Bryan, Robert P.; Esherick, Peter; Jewell, Jack L.; Lear, Kevin L.; Olbright, Gregory R.

    1997-01-01

    A monolithically integrated optoelectronic device is provided which integrates a vertical cavity surface emitting laser and either a photosensitive or an electrosensitive device either as input or output to the vertical cavity surface emitting laser either in parallel or series connection. Both vertical and side-by-side arrangements are disclosed, and optical and electronic feedback means are provided. Arrays of these devices can be configured to enable optical computing and neural network applications.

  17. General expression for spectrum of magnetic anomaly due to long tabular body and its characteristics

    Digital Repository Service at National Institute of Oceanography (India)

    Mishra, D.C.; Murthy, K.S.R.; Rao, T.C.S.

    A general expression for spectrum of magnetic anomalies-vertical, horizontal and total intensity - due to a long tabular body is derived which is used to estimate the body parameters. The analysis is extended to a marine magnetic anomaly recorded...

  18. Massive transfer of vertically aligned Si nanowire array onto alien substrates and their characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Shiu, Shu-Chia; Hung, Shih-Che; Chao, Jiun-Jie [Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan (China); Lin, Ching-Fuh, E-mail: cflin@cc.ee.ntu.edu.tw [Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan (China)

    2009-07-30

    Si nanowires (NWs) are promising materials for future electronic, photovoltaic, and sensor applications. So far the Si NWs are mainly formed on particular substrates or at high temperatures, greatly limiting their application flexibility. Here we report a low temperature process for forming and massively transferring vertically aligned Si NWs on alien substrates with a large density of about (3-5) x 10{sup 7} NWs/mm{sup 2}. The X-ray diffraction spectrum reveals that the transferred NWs exhibit almost the same crystal property as the bulk Si. Our investigation further shows that the transferred NWs have exceptional optical characteristics. The transferred Si NWs of 12.14 {mu}m exhibit the transmittance as low as 0.3% in the near infrared region and 0.07% in the visible region. The extracted absorption coefficient of Si NWs in the near infrared region is about 3 x 10{sup 3} cm{sup -1}, over 30 times larger than that of the bulk Si. Because of the low temperature process, it enables a large variety of alien substrates such as glass and plastics to be used. In addition, the exceptional properties of the transferred NWs offer potential applications for photovoltaic, photo-detectors, sensors, and flexible electronics.

  19. Autism Spectrum Disorder

    Science.gov (United States)

    Autism spectrum disorder (ASD) is a neurological and developmental disorder that begins early in childhood and lasts throughout a person's life. ... be known as Asperger syndrome and pervasive developmental disorders. It is called a "spectrum" disorder because people ...

  20. Vertical saccades in dyslexic children.

    Science.gov (United States)

    Tiadi, Aimé; Seassau, Magali; Bui-Quoc, Emmanuel; Gerard, Christophe-Loïc; Bucci, Maria Pia

    2014-11-01

    Vertical saccades have never been studied in dyslexic children. We examined vertical visually guided saccades in fifty-six dyslexic children (mean age: 10.5±2.56 years old) and fifty-six age matched non dyslexic children (mean age: 10.3±1.74 years old). Binocular eye movements were recorded using an infrared video-oculography system (mobileEBT®, e(ye)BRAIN). Dyslexic children showed significantly longer latency than the non dyslexic group, also the occurrence of anticipatory and express saccades was more important in dyslexic than in non dyslexic children. The gain and the mean velocity values were significantly smaller in dyslexic than in non dyslexic children. Finally, the up-down asymmetry reported in normal population for the gain and the velocity of vertical saccades was observed in dyslexic children and interestingly, dyslexic children also reported an up-down asymmetry for the mean latency. Taken together all these findings suggested impairment in cortical areas responsible of vertical saccades performance and also at peripheral level of the extra-ocular oblique muscles; moreover, a visuo-attentionnal bias could explain the up-down asymmetry reported for the vertical saccade triggering. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Waves, circulation and vertical dependence

    Science.gov (United States)

    Mellor, George

    2013-04-01

    Longuet-Higgins and Stewart (J Fluid Mech 13:481-504, 1962; Deep-Sea Res 11:529-562, 1964) and later Phillips (1977) introduced the problem of waves incident on a beach, from deep to shallow water. From the wave energy equation and the vertically integrated continuity equation, they inferred velocities to be Stokes drift plus a return current so that the vertical integral of the combined velocities was nil. As a consequence, it can be shown that velocities of the order of Stokes drift rendered the advective term in the momentum equation negligible resulting in a simple balance between the horizontal gradients of the vertically integrated elevation and wave radiation stress terms; the latter was first derived by Longuet-Higgins and Stewart. Mellor (J Phys Oceanogr 33:1978-1989, 2003a), noting that vertically integrated continuity and momentum equations were not able to deal with three-dimensional numerical or analytical ocean models, derived a vertically dependent theory of wave-circulation interaction. It has since been partially revised and the revisions are reviewed here. The theory is comprised of the conventional, three-dimensional, continuity and momentum equations plus a vertically distributed, wave radiation stress term. When applied to the problem of waves incident on a beach with essentially zero turbulence momentum mixing, velocities are very large and the simple balance between elevation and radiation stress gradients no longer prevails. However, when turbulence mixing is reinstated, the vertically dependent radiation stresses produce vertical velocity gradients which then produce turbulent mixing; as a consequence, velocities are reduced, but are still larger by an order of magnitude compared to Stokes drift. Nevertheless, the velocity reduction is sufficient so that elevation set-down obtained from a balance between elevation gradient and radiation stress gradients is nearly coincident with that obtained by the aforementioned papers. This paper

  2. Triplet State Resonance Raman Spectrum of all-trans-diphenylbutadiene

    DEFF Research Database (Denmark)

    Wilbrandt, Robert Walter; Grossman, W.E.L.; Killough, P.M

    1984-01-01

    The resonance Raman spectrum of all-trans-diphenylbutadiene (DPB) in its ground state and the resonance Raman spectrum (RRS) of DPB in its short-lived electronically excited triplet state are reported. Transient spectra were obtained by a pump-probe technique using two pulsed lasers....... The preresonance spectrum of the ground state is not significantly changed from that of the nonresonance spectrum. In the resonance spectrum of the triplet state the double-bond stretching mode of the butadiene part is shifted by 43 cm-1 downward to 1582 cm-1 whereas the single-bond stretching mode is essentially...

  3. Hybrid Vertical-Cavity Laser

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention provides a light source (2) for light circuits on a silicon platform (3). A vertical laser cavity is formed by a gain region (101) arranged between a top mirror (4) and a bottom grating-mirror (12) in a grating region (11) in a silicon layer (10) on a substrate. A waveguide...

  4. Physics and the Vertical Jump

    Science.gov (United States)

    Offenbacher, Elmer L.

    1970-01-01

    The physics of vertical jumping is described as an interesting illustration for motivating students in a general physics course to master the kinematics and dynamics of one dimensional motion. The author suggests that mastery of the physical principles of the jump may promote understanding of certain biological phenomena, aspects of physical…

  5. Multiservice Vertical Handoff Decision Algorithms

    Directory of Open Access Journals (Sweden)

    Zhu Fang

    2006-01-01

    Full Text Available Future wireless networks must be able to coordinate services within a diverse-network environment. One of the challenging problems for coordination is vertical handoff, which is the decision for a mobile node to handoff between different types of networks. While traditional handoff is based on received signal strength comparisons, vertical handoff must evaluate additional factors, such as monetary cost, offered services, network conditions, and user preferences. In this paper, several optimizations are proposed for the execution of vertical handoff decision algorithms, with the goal of maximizing the quality of service experienced by each user. First, the concept of policy-based handoffs is discussed. Then, a multiservice vertical handoff decision algorithm (MUSE-VDA and cost function are introduced to judge target networks based on a variety of user- and network-valued metrics. Finally, a performance analysis demonstrates that significant gains in the ability to satisfy user requests for multiple simultaneous services and a more efficient use of resources can be achieved from the MUSE-VDA optimizations.

  6. Importance of Vibronic Effects in the UV-Vis Spectrum of the 7,7,8,8-Tetracyanoquinodimethane Anion.

    Science.gov (United States)

    Tapavicza, Enrico; Furche, Filipp; Sundholm, Dage

    2016-10-11

    We present a computational method for simulating vibronic absorption spectra in the ultraviolet-visible (UV-vis) range and apply it to the 7,7,8,8-tetracyanoquinodimethane anion (TCNQ(-)), which has been used as a ligand in black absorbers. Gaussian broadening of vertical electronic excitation energies of TCNQ(-) from linear-response time-dependent density functional theory produces only one band, which is qualitatively incorrect. Thus, the harmonic vibrational modes of the two lowest doublet states were computed, and the vibronic UV-vis spectrum was simulated using the displaced harmonic oscillator approximation, the frequency-shifted harmonic oscillator approximation, and the full Duschinsky formalism. An efficient real-time generating function method was implemented to avoid the exponential complexity of conventional Franck-Condon approaches to vibronic spectra. The obtained UV-vis spectra for TCNQ(-) agree well with experiment; the Duschinsky rotation is found to have only a minor effect on the spectrum. Born-Oppenheimer molecular dynamics simulations combined with calculations of the electronic excitation energies for a large number of molecular structures were also used for simulating the UV-vis spectrum. The Born-Oppenheimer molecular dynamics simulations yield a broadening of the energetically lowest peak in the absorption spectrum, but additional vibrational bands present in the experimental and simulated quantum harmonic oscillator spectra are not observed in the molecular dynamics simulations. Our results underline the importance of vibronic effects for the UV-vis spectrum of TCNQ(-), and they establish an efficient method for obtaining vibronic spectra using a combination of linear-response time-dependent density functional theory and a real-time generating function approach.

  7. Vertically aligned carbon nanotube field-effect transistors

    KAUST Repository

    Li, Jingqi

    2012-10-01

    Vertically aligned carbon nanotube field-effect transistors (CNTFETs) have been developed using pure semiconducting carbon nanotubes. The source and drain were vertically stacked, separated by a dielectric, and the carbon nanotubes were placed on the sidewall of the stack to bridge the source and drain. Both the effective gate dielectric and gate electrode were normal to the substrate surface. The channel length is determined by the dielectric thickness between source and drain electrodes, making it easier to fabricate sub-micrometer transistors without using time-consuming electron beam lithography. The transistor area is much smaller than the planar CNTFET due to the vertical arrangement of source and drain and the reduced channel area. © 2012 Elsevier Ltd. All rights reserved.

  8. Field Emission of ITO-Coated Vertically Aligned Nanowire Array.

    KAUST Repository

    Lee, Changhwa

    2010-04-29

    An indium tin oxide (ITO)-coated vertically aligned nanowire array is fabricated, and the field emission characteristics of the nanowire array are investigated. An array of vertically aligned nanowires is considered an ideal structure for a field emitter because of its parallel orientation to the applied electric field. In this letter, a vertically aligned nanowire array is fabricated by modified conventional UV lithography and coated with 0.1-μm-thick ITO. The turn-on electric field intensity is about 2.0 V/μm, and the field enhancement factor, β, is approximately 3,078 when the gap for field emission is 0.6 μm, as measured with a nanomanipulator in a scanning electron microscope.

  9. Evidence for vertical transmission of HPV from mothers to infants.

    Science.gov (United States)

    Smith, Elaine M; Parker, Michael A; Rubenstein, Linda M; Haugen, Thomas H; Hamsikova, Eva; Turek, Lubomir P

    2010-01-01

    Few large studies have evaluated concordance based on a broad spectrum of human papillomavirus (HPV) types in oral and genital specimens of mothers and their recently born infants. This information is important in determining whether HPV vaccines administered prior to pregnancy may be useful for preventing vertical transmission. HPV DNA was positive in 30% of mothers and 1.5% of newborns. Maternal/newborn concordance (HPV+/+ or HPV-/-) was 71%. Among HPV DNA+ mothers, only 3% of their infants were DNA+ and only 1 pair had the same HPV type. Among HPV- women, 0.8% of infants were HPV+. HPV DNA detected in hospitalized newborns reflects current infection transmitted to infants during pregnancy or delivery. None of the mother/baby HPV DNA+ concordance pairs detected viral types found in HPV vaccines suggesting that vaccination prior to pregnancy is unlikely to be efficacious in preventing vertical transmission.

  10. Spin independent magnetoresistance effects in vertical graphene spin valves

    Science.gov (United States)

    Bodepudi, Srikrishna; Pratap Singh, Abhay; Pramanik, Sandipan

    2017-12-01

    Vertical spin valve device configuration with multilayer graphene (MLG) as spacer has drawn significant attention in recent years because of its potential to produce large magnetoresistance (MR) effect due to perfect spin filtering. However, demonstration of this effect has remained elusive so far. Here we consider MLG vertical spin valve structures and show that they exhibit spin independent MR effects, which are orders of magnitude stronger than the spin dependent effects reported to date. These effects manifest within a moderate field range of 10 kG and depend on various factors such as hybridization near the top graphene surface, doping, defects and interlayer coupling. These effects highlight the rich spectrum of physical phenomena that manifest in such systems, which could be exploited in low to moderate magnetic field sensing applications.

  11. Thiocyanate ligands as crucial elements for regeneration and photo-degradation in TiO{sub 2} vertical bar dye vertical bar CuI solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sirimanne, P.M. [Hahn-Meitner-Institut, Department Solare Energetik, Glienicker Str. 100, Alemania 14109 Berlin (Germany); Tributsch, H. [Hahn-Meitner-Institut, Department Solare Energetik, Glienicker Str. 100, Alemania 14109 Berlin (Germany)]. E-mail: tributsch@hmi.de

    2006-09-10

    Size control of CuI grains and thus better-matched interfaces were observed in the presence of crystal growth inhibitors in the CuI coating solution for TiO{sub 2} vertical bar dye vertical bar CuI solar cells. Evidence is given that these growth inhibitor molecules simultaneously act as an electron transfer mediator between the CuI and dye molecules via thiocyanate bridges. A reverse reaction of injected electrons from TiO{sub 2} nanoparticles electrochemically inactivates the thiocyanate electron transfer bridge in the illuminated cells causing photo-degradation.

  12. Measurement of the inclusive electron spectrum from B meson decays and determination of |Vub|

    Energy Technology Data Exchange (ETDEWEB)

    Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Brown, D. N.; Kolomensky, Yu. G.; Koch, H.; Schroeder, T.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; So, R. Y.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Kravchenko, E. A.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Lankford, A. J.; Gary, J. W.; Long, O.; Eisner, A. M.; Lockman, W. S.; Panduro Vazquez, W.; Chao, D. S.; Cheng, C. H.; Echenard, B.; Flood, K. T.; Hitlin, D. G.; Kim, J.; Miyashita, T. S.; Ongmongkolkul, P.; Porter, F. C.; Röhrken, M.; Huard, Z.; Meadows, B. T.; Pushpawela, B. G.; Sokoloff, M. D.; Sun, L.; Smith, J. G.; Wagner, S. R.; Bernard, D.; Verderi, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cibinetto, G.; Fioravanti, E.; Garzia, I.; Luppi, E.; Santoro, V.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Martellotti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rotondo, M.; Zallo, A.; Passaggio, S.; Patrignani, C.; Bhuyan, B.; Mallik, U.; Chen, C.; Cochran, J.; Prell, S.; Ahmed, H.; Gritsan, A. V.; Arnaud, N.; Davier, M.; Le Diberder, F.; Lutz, A. M.; Wormser, G.; Lange, D. J.; Wright, D. M.; Coleman, J. P.; Gabathuler, E.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Di Lodovico, F.; Sacco, R.; Cowan, G.; Banerjee, Sw.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Griessinger, K.; Hafner, A.; Schubert, K. R.; Barlow, R. J.; Lafferty, G. D.; Cenci, R.; Jawahery, A.; Roberts, D. A.; Cowan, R.; Cheaib, R.; Robertson, S. H.; Dey, B.; Neri, N.; Palombo, F.; Cremaldi, L.; Godang, R.; Summers, D. J.; Taras, P.; De Nardo, G.; Sciacca, C.; Raven, G.; Jessop, C. P.; LoSecco, J. M.; Honscheid, K.; Kass, R.; Gaz, A.; Margoni, M.; Posocco, M.; Simi, G.; Simonetto, F.; Stroili, R.; Akar, S.; Ben-Haim, E.; Bomben, M.; Bonneaud, G. R.; Calderini, G.; Chauveau, J.; Marchiori, G.; Ocariz, J.; Biasini, M.; Manoni, E.; Rossi, A.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Chrzaszcz, M.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Oberhof, B.; Paoloni, E.; Rama, M.; Rizzo, G.; Walsh, J. J.; Smith, A. J. S.; Anulli, F.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Pilloni, A.; Piredda, G.; Bünger, C.; Dittrich, S.; Grünberg, O.; Heß, M.; Leddig, T.; Voß, C.; Waldi, R.; Adye, T.; Wilson, F. F.; Emery, S.; Vasseur, G.; Aston, D.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dunwoodie, W.; Ebert, M.; Field, R. C.; Fulsom, B. G.; Graham, M. T.; Hast, C.; Innes, W. R.; Kim, P.; Leith, D. W. G. S.; Luitz, S.; Luth, V.; MacFarlane, D. B.; Muller, D. R.; Neal, H.; Ratcliff, B. N.; Roodman, A.; Sullivan, M. K.; Va’vra, J.; Wisniewski, W. J.; Purohit, M. V.; Wilson, J. R.; Randle-Conde, A.; Sekula, S. J.; Bellis, M.; Burchat, P. R.; Puccio, E. M. T.; Alam, M. S.; Ernst, J. A.; Gorodeisky, R.; Guttman, N.; Peimer, D. R.; Soffer, A.; Spanier, S. M.; Ritchie, J. L.; Schwitters, R. F.; Izen, J. M.; Lou, X. C.; Bianchi, F.; De Mori, F.; Filippi, A.; Gamba, D.; Lanceri, L.; Vitale, L.; Martinez-Vidal, F.; Oyanguren, A.; Albert, J.; Beaulieu, A.; Bernlochner, F. U.; King, G. J.; Kowalewski, R.; Lueck, T.; Nugent, I. M.; Roney, J. M.; Tasneem, N.; Gershon, T. J.; Harrison, P. F.; Latham, T. E.; Prepost, R.; Wu, S. L.

    2017-04-01

    Based on the full BABAR data sample of 466.5 million $B\\bar{B}$ pairs, we present measurements of the electron spectrum from semileptonic B meson decays. We fit the inclusive electron spectrum to distinguish Cabibbo-Kobayashi-Maskawa (CKM) suppressed B → Xueν decays from the CKM-favored B → Xceν decays, and from various other backgrounds, and determine the total semileptonic branching fraction B (B → Xeν) = ( 10.34 ± 0.04stat ± 0.2 6syst)%, averaged over B± and B0 mesons. We determine the spectrum and branching fraction for charmless B → Xueν decays and extract the CKM element | Vub| , by relying on four different QCD calculations based on the heavy quark expansion. While experimentally, the electron momentum region above 2.1 GeV / c is favored, because the background is relatively low, the uncertainties for the theoretical predictions are largest in the region near the kinematic endpoint. Detailed studies to assess the impact of these four predictions on the measurements of the electron spectrum, the branching fraction, and the extraction of the CKM matrix element |Vub| are presented, with the lower limit on the electron momentum varied from 0.8 GeV / c to the kinematic endpoint. We determine |Vub| using each of these different calculations and find, |Vub| = ( 3.794 ± 0.107exp $+ 0.292\\atop{ - 0.219 SF}$ $+ 0.078 \\atop{- 0.068 theory}$ ) × 10- 3 (De Fazio and Neubert), (4.563 ± 0.126exp $+ 0.230\\atop {- 0.208 SF}$ $+ 0.162\\atop{- 0.163 theory}$ ) ×10-3 (Bosch, Lange, Neubert, and Paz), (3.959 ± 0.104exp $+ 0.164\\atop{- 0.154 SF}$ $+ 0.042\\atop{ - 0.079 theory}$ ) × 10-3 (Gambino, Giordano, Ossola, and Uraltsev), (3.848 ± 0.108exp $+ 0.084\\atop{ - 0.070 theory}$) × 10-3 (dressed gluon exponentiation), where the stated

  13. How sensitive are high-pt electron spectra at RHIC to heavy quark energy loss?

    CERN Document Server

    Armesto, N; Dainese, A; Salgado, C A; Wiedemann, Urs Achim

    2006-01-01

    In nucleus-nucleus collisions, high-pt electron spectra depend on the medium modified fragmentation of their massive quark parents, thus giving novel access to the predicted mass hierarchy of parton energy loss. Here we calculate these spectra in a model, which supplements the perturbative QCD factorization formalism with parton energy loss. In general, we find - within large errors - rough agreement between theory and data on the single inclusive electron spectrum in pp, its nuclear modification factor, and its azimuthal anisotropy. However, the nuclear modification factor depends on the relative contribution of charm and bottom production, which we find to be affected by large perturbative uncertainties. In order for electron measurements to provide a significantly more stringent test of the expected mass hierarchy, one must then disentangle the b- and c-decay contributions, for instance by reconstructing the displaced decay vertices.

  14. Vertical Integration into Electronics: Transaction Costs and Organization Domain

    NARCIS (Netherlands)

    Sorge, A.; Batenburg, R.S.

    1999-01-01

    Transaction cost theory (TCT) had been posited, by Oliver Williamson, as a theoretically rigorous way of explaining the institutions that are found in capitalist economies, for regulating transactions in the face of bounded rationality and opportunism (Williamson 1995, 1996). The approach was

  15. Effects of anisotropy on the frequency spectrum of gravity waves observed by MST radar

    Science.gov (United States)

    Liu, C. H.

    1986-01-01

    In the investigation of gravity waves using mesosphere-stratosphere-troposphere radar data, model gravity-wave spectra have been used. In these model spectra, one usually assumes azimuthal symmetry. The effect of spectral anisotropy on the observed spectrum is studied here. It is shown that for a general Garrett-Munk-type spectrum, the anisotropy does not affect the frequency spectrum observed by the vertically beamed radar. For the oblique beam, however, the observed frequency spectrum is changed. A general gravity wave spectrum including azimuthal anisotropy is considered.

  16. Coexistence of Strategic Vertical Separation and Integration

    DEFF Research Database (Denmark)

    Jansen, Jos

    2003-01-01

    This paper gives conditions under which vertical separation is chosen by some upstream firms, while vertical integration is chosen by others in the equilibrium of a symmetric model. A vertically separating firm trades off fixed contracting costs against the strategic benefit of writing a (two......-part tariff, exclusive dealing) contract with its retailer. Coexistence emerges when more than two vertical Cournot oligopolists supply close substitutes. When vertical integration and separation coexist, welfare could be improved by reducing the number of vertically separating firms. The scope...

  17. Kinematic Fitting of Detached Vertices

    Energy Technology Data Exchange (ETDEWEB)

    Mattione, Paul [Rice Univ., Houston, TX (United States)

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  18. Vertical distribution of Arctic methane

    Science.gov (United States)

    Tukiainen, Simo; Karppinen, Tomi; Hakkarainen, Janne; Kivi, Rigel; Heikkinen, Pauli; Tamminen, Johanna

    2017-04-01

    In this study we show the vertical distribution of atmospheric methane (CH4) measured in Sodankylä, Northern Finland. The CH4 profiles are retrieved from the direct Sun FTS measurements using the dimension reduction retrieval method. In the retrieval method, we have a few degrees of freedom about the profile shape. The data set covers years 2010-2016 (from February to November) and altitudes 0-40 km. The retrieved FTS profiles are validated against ACE satellite measurements and AirCore balloon measurements. The total columns derived from the FTS profiles are compared to the official TCCON XCH4 data. A vertically resolved methane data set can be used, e.g., to study stratospheric methane during the polar vortex.

  19. INTERNATIONAL SPECIALIZATION AND VERTICAL DIFFERENTIATION

    Directory of Open Access Journals (Sweden)

    Furia Donatella

    2010-07-01

    Full Text Available During the last decades, market segmentation and intra-industry trade have become increasingly relevant. The underlying hypothesis of our work is that distinct articles have heterogeneous potential for vertical differentiation, implying that different patterns of international specialization should be identifiable. We carry out an analysis on revealed comparative advantage (through the Lafay Index in specific sectors of interest. Then we highlight the emergence of diverse degrees of product quality differentiation among sectors (through the Relative Quality Index. Results confirm our hypothesis. Indeed it appears that only certain goods, for which the pace of either creative or technological innovation (or both is particularly fast, present a high degree of vertical differentiation and market segmentation. This allows countries to specialize in a particular product variety and gain market power position for that variety. These findings should be taken in due consideration when designing trade policies.

  20. Poligonación Vertical

    Directory of Open Access Journals (Sweden)

    Esteban Dörries

    2016-03-01

    Full Text Available La poligonación vertical es un método de medición de diferencias de altura que aprovecha las posibilidades de las estaciones totales. Se presta fundamentalmente para líneas de nivelación entre nodos formando red. El nombre se debe a que las visuales sucesivas se proyectan sobre aristas verticales en lugar de un plano horizontal, como ocurre en la poligonación convencional.

  1. Vertical Launch System Loadout Planner

    Science.gov (United States)

    2015-03-01

    United States Navy USS United States’ Ship VBA Visual Basic for Applications VLP VLS Loadout Planner VLS Vertical Launch System...mathematically complex and require training to operate the software. A Visual Basic for Applications ( VBA ) Excel (Microsoft Corporation, 2015...lockheed/data/ms2/documents/laun chers/MK41 VLS factsheet.pdf Microsoft Excel version 14.4.3, VBA computer software. (2011). Redmond, WA: Microsoft

  2. Trade Liberalisation and Vertical Integration

    DEFF Research Database (Denmark)

    Bache, Peter Arendorf; Laugesen, Anders

    We build a three-country model of international trade in final goods and intermediate inputs and study the relation between different types of trade liberalisation and vertical integration. Firms are heterogeneous with respect to both productivity and factor intensity as observed in data. Final......-economy property rights theory of the firm using firm-level data. Finally, we notice that our model's sorting pattern is in line with recent evidence when the wage difference across countries is not too big....

  3. Prophylaxis of vertical HBV infection.

    Science.gov (United States)

    Pawlowska, Malgorzata; Pniewska, Anna; Pilarczyk, Malgorzata; Kozielewicz, Dorota; Domagalski, Krzysztof

    2016-10-01

    An appropriate management of HBV infection is the best strategy to finally reduce the total burden of HBV infection. Mother-to-child transmission (MTCT) is responsible for more than one third of chronic HBV infections worldwide. Because HBV infection in infancy or early childhood often leads to chronic infection, appropriate prophylaxis and management of HBV in pregnancy is crucial to prevent MTCT. The prevention of HBV vertical transmission is a complex task and includes: universal HBV screening of pregnant women, administration of antivirals in the third trimester of pregnancy in women with high viral load and passive-active HBV immunoprophylaxis with hepatitis B vaccine and hepatitis B immune globulin in newborns of all HBV infected women. Universal screening of pregnant women for HBV infection, early identification of HBV DNA level in HBV-infected mothers, maternal treatment with class B according to FDA antivirals and passive/active anti-HBV immunoprophylaxis to newborns of HBV-positive mothers are crucial strategies for reducing vertical HBV transmission rates. Consideration of caesarean section in order to reduce the risk of vertical HBV transmission should be recommend in HBV infected pregnant women with high viral load despite antiviral therapy or when the therapy in the third trimester of pregnancy is not available.

  4. Transverse vertical dispersion in groundwater and the capillary fringe.

    Science.gov (United States)

    Klenk, I D; Grathwohl, P

    2002-09-01

    Transverse dispersion is the most relevant process in mass transfer of contaminants across the capillary fringe (both directions), dilution of contaminants, and mixing of electron acceptors and electron donors in biodegrading groundwater plumes. This paper gives an overview on literature values of transverse vertical dispersivities alpha(tv) measured at different flow velocities and compares them to results from well-controlled laboratory-tank experiments on mass transfer of trichloroethene (TCE) across the capillary fringe. The measured values of transverse vertical dispersion in the capillary fringe region were larger than in fully saturated media, which is credited to enhanced tortuosity of the flow paths due to entrapped air within the capillary fringe. In all cases, the values observed for alpha(tv) were model, based on the mean square displacement and the pore size accounting for only partial diffusive mixing at increasing flow velocities, shows very good agreement with measured and published data.

  5. [Vertical fractures: apropos of 2 clinical cases].

    Science.gov (United States)

    Félix Mañes Ferrer, J; Micò Muñoz, P; Sánchez Cortés, J L; Paricio Martín, J J; Miñana Laliga, R

    1991-01-01

    The aim of the study is to present a clinical review of the vertical root fractures. Two clinical cases are presented to demonstrates the criteria for obtaining a correct diagnosis of vertical root fractures.

  6. 5G Spectrum Sharing

    OpenAIRE

    Nekovee, Maziar; Rudd, Richard

    2017-01-01

    In this paper an overview is given of the current status of 5G industry standards, spectrum allocation and use cases, followed by initial investigations of new opportunities for spectrum sharing in 5G using cognitive radio techniques, considering both licensed and unlicensed scenarios. A particular attention is given to sharing millimeter-wave frequencies, which are of prominent importance for 5G.

  7. Synthesis of Vertically-Aligned Zinc Oxide Nanowires and Their Application as a Photocatalyst

    Directory of Open Access Journals (Sweden)

    Qiong Zhou

    2017-01-01

    Full Text Available Vertically aligned zinc oxide (ZnO nanowires were hydrothermally synthesized on a glass substrate with the assistance of a pre-coated ZnO seeding layer. The crystalline structure, morphology and transmission spectrum of the as-synthesized sample were characterized by X-ray diffraction (XRD, field-emission scanning electron microscopy (FE-SEM, and ultraviolet-visible (UV-Vis spectrophotometry, respectively, indicating a wurzite ZnO material of approximately 100 nm wire diameter and absorbance at 425 nm and lower wavelengths. The photocatalytic activity of the sample was tested via the degradation of methyl orange in aqueous solution under UV-A irradiation. The synthesized nanowires showed a high photocatalytic activity, which increased up to 90% degradation in 2 h as pH was increased to 12. It was shown that the photocatalytic activity of the nanowires was proportional to the length to diameter ratio of the nanowires, which was in turn controlled by the growth time and grain size of the seed layer. Estimates suggest that diffusion into the regions between nanowires may be significantly hindered. Finally, the reusability of the prepared ZnO nanowire samples was also investigated, with results showing that the nanowires still showed 97% of its original photoactivity after ten cycles of use.

  8. Synthesis of Vertically-Aligned Zinc Oxide Nanowires and Their Application as a Photocatalyst

    Science.gov (United States)

    Zhou, Qiong; Wen, John Z.; Zhao, Pei; Anderson, William A.

    2017-01-01

    Vertically aligned zinc oxide (ZnO) nanowires were hydrothermally synthesized on a glass substrate with the assistance of a pre-coated ZnO seeding layer. The crystalline structure, morphology and transmission spectrum of the as-synthesized sample were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and ultraviolet-visible (UV-Vis) spectrophotometry, respectively, indicating a wurzite ZnO material of approximately 100 nm wire diameter and absorbance at 425 nm and lower wavelengths. The photocatalytic activity of the sample was tested via the degradation of methyl orange in aqueous solution under UV-A irradiation. The synthesized nanowires showed a high photocatalytic activity, which increased up to 90% degradation in 2 h as pH was increased to 12. It was shown that the photocatalytic activity of the nanowires was proportional to the length to diameter ratio of the nanowires, which was in turn controlled by the growth time and grain size of the seed layer. Estimates suggest that diffusion into the regions between nanowires may be significantly hindered. Finally, the reusability of the prepared ZnO nanowire samples was also investigated, with results showing that the nanowires still showed 97% of its original photoactivity after ten cycles of use. PMID:28336843

  9. Structural and Electrical Investigation of C60-Graphene Vertical Heterostructures.

    Science.gov (United States)

    Kim, Kwanpyo; Lee, Tae Hoon; Santos, Elton J G; Jo, Pil Sung; Salleo, Alberto; Nishi, Yoshio; Bao, Zhenan

    2015-06-23

    Graphene, with its unique electronic and structural qualities, has become an important playground for studying adsorption and assembly of various materials including organic molecules. Moreover, organic/graphene vertical structures assembled by van der Waals interaction have potential for multifunctional device applications. Here, we investigate structural and electrical properties of vertical heterostructures composed of C60 thin film on graphene. The assembled film structure of C60 on graphene is investigated using transmission electron microscopy, which reveals a uniform morphology of C60 film on graphene with a grain size as large as 500 nm. The strong epitaxial relations between C60 crystal and graphene lattice directions are found, and van der Waals ab initio calculations support the observed phenomena. Moreover, using C60-graphene heterostructures, we fabricate vertical graphene transistors incorporating n-type organic semiconducting materials with an on/off ratio above 3 × 10(3). Our work demonstrates that graphene can serve as an excellent substrate for assembly of molecules, and attained organic/graphene heterostructures have great potential for electronics applications.

  10. Determinations of vertical stroke V{sub cb} vertical stroke and vertical stroke V{sub ub} vertical stroke from baryonic Λ{sub b} decays

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Y.K. [Shanxi Normal University, School of Physics and Information Engineering, Linfen (China); National Tsing Hua University, Department of Physics, Hsinchu (China); Geng, C.Q. [Shanxi Normal University, School of Physics and Information Engineering, Linfen (China); National Tsing Hua University, Department of Physics, Hsinchu (China); Hunan Normal University, Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), Changsha (China)

    2017-10-15

    We present the first attempt to extract vertical stroke V{sub cb} vertical stroke from the Λ{sub b} → Λ{sub c}{sup +}l anti ν{sub l} decay without relying on vertical stroke V{sub ub} vertical stroke inputs from the B meson decays. Meanwhile, the hadronic Λ{sub b} → Λ{sub c}M{sub (c)} decays with M = (π{sup -},K{sup -}) and M{sub c} =(D{sup -},D{sup -}{sub s}) measured with high precisions are involved in the extraction. Explicitly, we find that vertical stroke V{sub cb} vertical stroke =(44.6 ± 3.2) x 10{sup -3}, agreeing with the value of (42.11 ± 0.74) x 10{sup -3} from the inclusive B → X{sub c}l anti ν{sub l} decays. Furthermore, based on the most recent ratio of vertical stroke V{sub ub} vertical stroke / vertical stroke V{sub cb} vertical stroke from the exclusive modes, we obtain vertical stroke V{sub ub} vertical stroke = (4.3 ± 0.4) x 10{sup -3}, which is close to the value of (4.49 ± 0.24) x 10{sup -3} from the inclusive B → X{sub u}l anti ν{sub l} decays. We conclude that our determinations of vertical stroke V{sub cb} vertical stroke and vertical stroke V{sub ub} vertical stroke favor the corresponding inclusive extractions in the B decays. (orig.)

  11. Electronics and electronic systems

    CERN Document Server

    Olsen, George H

    1987-01-01

    Electronics and Electronic Systems explores the significant developments in the field of electronics and electronic devices. This book is organized into three parts encompassing 11 chapters that discuss the fundamental circuit theory and the principles of analog and digital electronics. This book deals first with the passive components of electronic systems, such as resistors, capacitors, and inductors. These topics are followed by a discussion on the analysis of electronic circuits, which involves three ways, namely, the actual circuit, graphical techniques, and rule of thumb. The remaining p

  12. ?Vertical Sextants give Good Sights?

    Science.gov (United States)

    Richey, Michael

    Mark Dixon suggests (Forum, Vol. 50, 137) that nobody thus far has attempted to quantify the errors from tilt that arise while observing with the marine sextant. The issue in fact, with the related problem of what exactly is the axis about which the sextant is rotated whilst being (to define the vertical), was the subject of a lively controversy in the first two volumes of this Journal some fifty years ago. Since the consensus of opinion seems to have been that the maximum error does not necessarily occur at 45 degrees, whereas Dixon's table suggests that it does, some reiteration of the arguments may be in order.

  13. BATCH SETTLING IN VERTICAL SETTLERS

    OpenAIRE

    Lama Ramirez, R.; Universidad Nacional Mayor De San Marcos Facultad de Química e Ingeniería Química Departamento de Operaciones Unitarias Av. Venezuela cdra. 34 sin, Lima - Perú; Condorhuamán Ccorimanya, C.; Universidad Nacional Mayor De San Marcos Facultad de Química e Ingeniería Química Departamento de Operaciones Unitarias Av. Venezuela cdra. 34 sin, Lima - Perú

    2014-01-01

    lt has been studied the batch sedimentation of aqueous suspensions of precipitated calcium carbonate, barium sulphate and lead oxide , in vertical thickeners of rectangular and circular cross sectional area. Suspensions vary in concentration between 19.4 and 617.9 g/I and the rate of sedimentation obtained between 0.008 and 7.70 cm/min. The effect of the specific gravity of the solid on the rate of sedimentation is the same for all the suspensions, that is, the greater the value of the specif...

  14. Binocular responses and vertical strabismus

    Directory of Open Access Journals (Sweden)

    Risović Dušica

    2007-01-01

    Full Text Available Background/Aim. Elevation in adduction is the most common pattern of vertical strabismus, and it is mostly treated with surgery. The results of weaking of inferior oblique muscle are very changeable. The aim of this study was to evaluate binocular vision using sensory tests before and one and six months after the surgery. Methods. A total of 79 children were divided in two groups: the first, with inferior oblique muscle of overaction (n = 52, and the second with dissociated vertical deviation (DVD, and primary inferior oblique muscle overaction (n = 27. We tested them by polaroid mirror test (PMT, Worth test at distance and near, fusion amplitudes on sinoptofore, Lang I stereo test and Wirt-Titmus stereo test. We examined our patients before and two times after the surgery for vertical strabismus. Results. Foveal suppression in the group I was found in 60.5% of the patients before, and in 56.4% after the surgery. In group II Foveal suppression was detected in 64.7% of the patients before, but in 55.6% 6 months after the surgery with PMT. Worth test revealed suppression in 23.5% of the patients before, and in 40.7% after the vertical muscle surgery. Parafoveal fussion persisted in about 1/3 of the patients before the surgery, and their amplitudes were a little larger after the surgery in the group I patients. Lang I stereo test was negative in 53.9% before and 51.9% after the surgery in the group I, and in 48.2% of the patients before and after the surgery in the group II patients. Wirt-Titmus stereo test was negative in 74.5% of the patients before and in 72.9% after the surgery in the group I, but in the group II it was negative in 70.8% before and in 68.0% of the patients 6 months after the surgery. Conclusion. Binocular responses were found after surgery in 65.7% of the patients the group I and in 55.6% patients the group II. There was no significant difference between these two groups, but binocular responses were more often in the patients

  15. The Neutron Spectrum in a Uranium Tube

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, E.; Jonsson, E.; Lindberg, M.; Mednis, J.

    1963-10-15

    A series of experimental and theoretical investigations on neutron spectra in lattice cells has been started at the reactor R1. This report gives the results from the first one of these cells - one with a tube of natural -uranium surrounded by heavy water. In the measurements the cell was placed in the central, vertical channel of the reactor. The neutron spectrum from a lead scatterer in the uranium tube - outer diameter 49.2 mm, inner diameter 28.3 mm - was measured with a fast chopper in the energy region 0.01 to 100 eV. Subsidiary measurements indicated that the spectrum in the beam from the lead piece corresponds to the spectrum of the angular flux integrated over all angles. This correspondence is important for the interpretation of the experimental data. The thermal part of the spectrum was found to deviate significantly from a Maxwellian. However, the deviation is not very large, and one could use a Maxwellian, at least to give a rough idea of the hardness of the spectrum. For the present tube the temperature of this Maxwellian was estimated as 90 to 100 deg C above the moderator temperature (33 deg C). In the joining region the rise of the spectrum towards the thermal part is slower than for the cell boundary spectrum, measured earlier. In the epithermal region the limited resolution of the chopper has affected the measurements at the energies of the uranium resonances. However, the shape of the spectrum on the flanks of the first resonance in {sup 238}U (6.68 eV) has been obtained accurately. In the theoretical treatment the THERMOS code with a free gas scattering model has been used. The energy region was 3.06 - 0.00025 eV. The agreement with the measurements is good for the thermal part - possibly the theoretical spectrum is a little softer than the experimental one. In the joining region the results from THERMOS are comparatively high - probably due to the scattering model used.

  16. Effects of volume averaging on the line spectra of vertical velocity from multiple-Doppler radar observations

    Science.gov (United States)

    Gal-Chen, T.; Wyngaard, J. C.

    1982-01-01

    Calculations of the ratio of the true one-dimensional spectrum of vertical velocity and that measured with multiple-Doppler radar beams are presented. It was assumed that the effects of pulse volume averaging and objective analysis routines is replacement of a point measurement with a volume integral. A u and v estimate was assumed to be feasible when orthogonal radars are not available. Also, the target fluid was configured as having an infinite vertical dimension, zero vertical velocity at the top and bottom, and having homogeneous and isotropic turbulence with a Kolmogorov energy spectrum. The ratio obtained indicated that equal resolutions among radars yields a monotonically decreasing, wavenumber-dependent response function. A gain of 0.95 was demonstrated in an experimental situation with 40 levels. Possible errors introduced when using unequal resolution radars were discussed. Finally, it was found that, for some flows, the extent of attenuation depends on the number of vertical levels resolvable by the radars.

  17. Theoretical spectrum of noisy optical pulse trains.

    Science.gov (United States)

    Lacaze, B; Chabert, M

    2008-06-20

    The intensity of an ideal optical pulse train is often modeled as an exact periodic repetition of a given pulse-shape function with constant amplitude and width. Therefore, the ideal intensity power spectrum is a pure line power spectrum. However, spontaneous-emission noise due to amplification media, electronic noise due to modulators, or even intentional modulations result in period-to-period fluctuations of the pulse amplitude, width, or arrival time. The power spectrum of this so-called noisy optical pulse train is then composed of a line spectrum added to a band spectrum. This study shows that the optical pulse train intensity is cyclostationary under usual assumptions on the fluctuations. This property allows us to derive the exact optical pulse train power spectrum. A general closed-form expression that takes into account the three noise manifestations (jitter, amplitude, and width modulations) is provided. Particular expressions are given for usual cases of interest such as the jitter and amplitude modulation model, for given fluctuation probability distributions, and pulse-shape functions.

  18. The marine diversity spectrum

    DEFF Research Database (Denmark)

    Reuman, Daniel C.; Gislason, Henrik; Barnes, Carolyn

    2014-01-01

    of taxonomy (all the species in a region regardless of clade) are much less studied but are equally important and will illuminate a different set of ecological and evolutionary processes. We develop and test a mechanistic model of how diversity varies with body mass in marine ecosystems. The model predicts...... the form of the diversity spectrum', which quantifies the distribution of species' asymptotic body masses, is a species analogue of the classic size spectrum of individuals, and which we have found to be a new and widely applicable description of diversity patterns. The marine diversity spectrum...... is predicted to be approximately linear across an asymptotic mass range spanning seven orders of magnitude. Slope -0 center dot 5 is predicted for the global marine diversity spectrum for all combined pelagic zones of continental shelf seas, and slopes for large regions are predicted to lie between -0 center...

  19. Fetal Alcohol Spectrum Disorders

    Science.gov (United States)

    Alcohol can harm your baby at any stage during a pregnancy. That includes the earliest stages, before ... can cause a group of conditions called fetal alcohol spectrum disorders (FASDs). Children who are born with ...

  20. Fast Spectrum Reactors

    CERN Document Server

    Todd, Donald; Tsvetkov, Pavel

    2012-01-01

    Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addit...

  1. Autism Spectrum Disorder (ASD)

    Science.gov (United States)

    ... Español (Spanish) Recommend on Facebook Tweet Share Compartir Autism spectrum disorder (ASD) is a developmental disability that ... interview about being fathers of sons who have autism. Watch more Autism videos COMMUNITY REPORT The Community ...

  2. Autism spectrum disorder - Asperger syndrome

    Science.gov (United States)

    ... part of the larger developmental disorder category of autism spectrum disorder . ... American Psychiatric Association. Autism spectrum disorder. ... VA: American Psychiatric Publishing: 2013;50-59. Raviola GJ, ...

  3. Multi-component ground motion response spectra for coupled horizontal, vertical, angular accelerations, and tilt

    Science.gov (United States)

    Kalkan, E.; Graizer, V.

    2007-01-01

    Rotational and vertical components of ground motion are almost always ignored in design or in the assessment of structures despite the fact that vertical motion can be twice as much as the horizontal motion and may exceed 2g level, and rotational excitation may reach few degrees in the proximity of fault rupture. Coupling of different components of ground excitation may significantly amplify the seismic demand by introducing additional lateral forces and enhanced P-?? effects. In this paper, a governing equation of motion is postulated to compute the response of a SDOF oscillator under a multi-component excitation. The expanded equation includes secondary P-?? components associated with the combined impacts of tilt and vertical excitations in addition to the inertial forcing terms due to the angular and translational accelerations. The elastic and inelastic spectral ordinates traditionally generated considering the uniaxial input motion are compared at the end with the multi-component response spectra of coupled horizontal, vertical and tilting motions. The proposed multi-component response spectrum reflects kinematic characteristics of the ground motion that are not identifiable by the conventional spectrum itself, at least for the near-fault region where high intensity vertical shaking and rotational excitation are likely to occur.

  4. Continuum limit of gl(M vertical stroke N) spin chains

    Energy Technology Data Exchange (ETDEWEB)

    Candu, Constantin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie

    2011-03-15

    We study the spectrum of an integrable antiferromagnetic Hamiltonian of the gl(M vertical stroke N) spin chain of alternating fundamental and dual representations. After extensive numerical analysis, we identify the vacuum and low lying excitations and with this knowledge perform the continuum limit, while keeping a finite gap. All antiferromagnetic gl(n+N vertical stroke N) spin chains with n>0 and N{ne}0 are shown to possess in the continuum limit 2n-2 multiplets of massive particles which scatter with gl(n) Gross-Neveu like S-matrices, namely their eigenvalues do not depend on N. We argue that the continuum theory is the gl(M vertical stroke N) Gross-Neveu model, that is the massive deformation of the gl(M vertical stroke N){sub 1} Wess-Zumino-Witten model. As we can see ion the example of gl(2m vertical stroke 1) spin chains, the full particle spectrum is much richer. Our analysis suggests that for a complete characterization of the latter it is not enough to restrict to large volume calculations, as we do in this work. (orig.)

  5. Capillary holdup between vertical spheres

    Directory of Open Access Journals (Sweden)

    S. Zeinali Heris

    2009-12-01

    Full Text Available The maximum volume of liquid bridge left between two vertically mounted spherical particles has been theoretically determined and experimentally measured. As the gravitational effect has not been neglected in the theoretical model, the liquid interface profile is nonsymmetrical around the X-axis. Symmetry in the interface profile only occurs when either the particle size ratio or the gravitational force becomes zero. In this paper, some equations are derived as a function of the spheres' sizes, gap width, liquid density, surface tension and body force (gravity/centrifugal to estimate the maximum amount of liquid that can be held between the two solid spheres. Then a comparison is made between the result based on these equations and several experimental results.

  6. Vertical Transistors Based on 2D Materials: Status and Prospects

    Directory of Open Access Journals (Sweden)

    Filippo Giannazzo

    2018-01-01

    Full Text Available Two-dimensional (2D materials, such as graphene (Gr, transition metal dichalcogenides (TMDs and hexagonal boron nitride (h-BN, offer interesting opportunities for the implementation of vertical transistors for digital and high-frequency electronics. This paper reviews recent developments in this field, presenting the main vertical device architectures based on 2D/2D or 2D/3D material heterostructures proposed so far. For each of them, the working principles and the targeted application field are discussed. In particular, tunneling field effect transistors (TFETs for beyond-CMOS low power digital applications are presented, including resonant tunneling transistors based on Gr/h-BN/Gr stacks and band-to-band tunneling transistors based on heterojunctions of different semiconductor layered materials. Furthermore, recent experimental work on the implementation of the hot electron transistor (HET with the Gr base is reviewed, due to the predicted potential of this device for ultra-high frequency operation in the THz range. Finally, the material sciences issues and the open challenges for the realization of 2D material-based vertical transistors at a large scale for future industrial applications are discussed.

  7. Vertical jump coordination: fatigue effects.

    Science.gov (United States)

    Rodacki, André Luiz Felix; Fowler, Neil E; Bennett, Simon J

    2002-01-01

    The aim of this study was to investigate the segmental coordination of vertical jumps under fatigue of the knee extensor and flexor muscles. Eleven healthy and active subjects performed maximal vertical jumps with and without fatigue, which was imposed by requesting the subjects to extend/flex their knees continuously in a weight machine, until they could not lift a load corresponding to approximately 50% of their body weight. Knee extensor and flexor isokinetic peak torques were also measured before and after fatigue. Video, ground reaction forces, and electromyographic data were collected simultaneously and used to provide several variables of the jumps. Fatiguing the knee flexor muscles did not reduce the height of the jumps or induce changes in the kinematic, kinetic, and electromyographic profiles. Knee extensor fatigue caused the subjects to adjust several variables of the movement, in which the peak joint angular velocity, peak joint net moment, and power around the knee were reduced and occurred earlier in comparison with the nonfatigued jumps. The electromyographic data analyses indicated that the countermovement jumps were performed similarly, i.e., a single strategy was used, irrespective of which muscle group (extensor or flexors) or the changes imposed on the muscle force-generating characteristics (fatigue or nonfatigue). The subjects executed the movements as if they scaled a robust template motor program, which guided the movement execution in all jump conditions. It was speculated that training programs designed to improve jump height performance should avoid severe fatigue levels, which may cause the subjects to learn and adopt a nonoptimal and nonspecific coordination solution. It was suggested that the neural input used in the fatigued condition did not constitute an optimal solution and may have played a role in decreasing maximal jump height achievement.

  8. Loading effects in GPS vertical displacement time series

    Science.gov (United States)

    Memin, A.; Boy, J. P.; Santamaría-Gómez, A.; Watson, C.; Gravelle, M.; Tregoning, P.

    2015-12-01

    Surface deformations due to loading, with yet no comprehensive representation, account for a significant part of the variability in geodetic time series. We assess effects of loading in GPS vertical displacement time series at several frequency bands. We compare displacement derived from up-to-date loading models to two global sets of positioning time series, and investigate how they are reduced looking at interannual periods (> 2 months), intermediate periods (> 7 days) and the whole spectrum (> 1day). We assess the impact of interannual loading on estimating velocities. We compute atmospheric loading effects using surface pressure fields from the ECMWF. We use the inverted barometer (IB) hypothesis valid for periods exceeding a week to describe the ocean response to the pressure forcing. We used general circulation ocean model (ECCO and GLORYS) to account for wind, heat and fresh water flux. We separately use the Toulouse Unstructured Grid Ocean model (TUGO-m), forced by air pressure and winds, to represent the dynamics of the ocean response at high frequencies. The continental water storage is described using GLDAS/Noah and MERRA-land models. Non-hydrology loading reduces the variability of the observed vertical displacement differently according to the frequency band. The hydrology loading leads to a further reduction mostly at annual periods. ECMWF+TUGO-m better agrees with vertical surface motion than the ECMWF+IB model at all frequencies. The interannual deformation is time-correlated at most of the locations. It is adequately described by a power-law process of spectral index varying from -1.5 to -0.2. Depending on the power-law parameters, the predicted non-linear deformation due to mass loading variations leads to vertical velocity biases up to 0.7 mm/yr when estimated from 5 years of continuous observations. The maximum velocity bias can reach up to 1 mm/yr in regions around the southern Tropical band.

  9. New calorimetric all-particle energy spectrum

    Science.gov (United States)

    Linsley, J.

    1985-01-01

    Both the maximum size N sub m and the sea level muon size N sub mu have been used separately to find the all-particle energy spectrum in the air shower domain. However the conversion required, whether from N sub m to E or from N sub mu to E, has customarily been carried out by means of calculations based on an assumed cascase model. It is shown here that by combining present data on N sub m and N sub mu spectra with data on: (1); the energy spectrum of air shower muons and (2) the average width of the electron profile, one can obtain empirical values of the N sub m to E and N sub mu to E conversion factors, and an empirical calorimetric all-particle spectrum, in the energy range 2 x 10 to the 6th power E 2 x 10 to the 9th power GeV.

  10. Spin resonance strengths for radiative polarization and vertical momentum recoils using the spin response formalism

    Energy Technology Data Exchange (ETDEWEB)

    Mane, S.R. [Convergent Computing Inc., P.O. Box 561, Shoreham, NY 11786 (United States)], E-mail: srmane@optonline.net

    2008-08-21

    The radiative polarization of electrons and positrons in storage rings includes spin resonances driven by vertical momentum recoils due to spin flip photon emissions. This is in addition to the spin resonances driven by longitudinal momentum recoils. The underlying physics for the vertical momentum recoils is similar to the perturbations induced by a radial field (rf) dipole spin flipper. This paper derives the spin resonance strengths driven by the vertical momentum recoils using known techniques for spin flippers, such as the spin response formalism.

  11. The ISO-SWS spectrum of planetary nebula NGC 7027

    NARCIS (Netherlands)

    Salas, JB; Pottasch, [No Value; Beintema, DA; Wesselius, PR

    We present the infrared spectrum of the planetary nebula NGC7027 observed with the Short Wavelength Spectrometer (SWS), on board the Infrared Space Observatory (ISO). These data allow us to derive the electron density and, together with the IUE and optical spectra, the electron temperature for

  12. Oscillations in the spectrum of nonlinear Thomson-backscattered radiation

    Directory of Open Access Journals (Sweden)

    C. A. Brau

    2004-02-01

    Full Text Available When an electron beam collides with a high-intensity laser beam, the spectrum of the nonlinear Thomson scattering in the backward direction shows strong oscillations like those in the spectrum of an optical klystron. Laser gain on the backward Thomson scattering is estimated using the Madey theorem, and the results suggest that Thomson-backscatter free-electron lasers are possible at wavelengths extending to the far uv using a terawatt laser beam from a chirped-pulse amplifier and a high-brightness electron beam from a needle cathode.

  13. $\\Delta(1232)$-Resonance in the Hydrogen Spectrum

    OpenAIRE

    Hagelstein, Franziska

    2018-01-01

    The electromagnetic excitation of the $\\Delta(1232)$-resonance plays an appreciable role in the Lamb shift and hyperfine structure of muonic and electronic hydrogen. Its effect appears at the subleading order $\\mathcal{O}(\\alpha^5)$, together with other proton-polarizability contributions from forward two-photon exchange. We use the large-$N_c$ relations for the nucleon-to-delta transition form factors to compute the effect of the $\\Delta(1232)$ in the hydrogen spectrum. We pay particular att...

  14. Bottomonium spectrum revisited

    CERN Document Server

    Segovia, Jorge; Entem, David R.; Fernández, Francisco

    2016-01-01

    We revisit the bottomonium spectrum motivated by the recently exciting experimental progress in the observation of new bottomonium states, both conventional and unconventional. Our framework is a nonrelativistic constituent quark model which has been applied to a wide range of hadronic observables from the light to the heavy quark sector and thus the model parameters are completely constrained. Beyond the spectrum, we provide a large number of electromagnetic, strong and hadronic decays in order to discuss the quark content of the bottomonium states and give more insights about the better way to determine their properties experimentally.

  15. Lidar measured vertical atmospheric scattering profiles

    NARCIS (Netherlands)

    Kunz, G.J.

    1985-01-01

    The vertical structure of the atmosphere, which is of invaluable interest to meteorologists, geo-physicists and environmental researchers, can be measured with LIDAR. A method has been proposed and applied to invert lidar signals from vertical soundings to height resolved scattering coefficients. In

  16. Vertical integration from the large Hilbert space

    Science.gov (United States)

    Erler, Theodore; Konopka, Sebastian

    2017-12-01

    We develop an alternative description of the procedure of vertical integration based on the observation that amplitudes can be written in BRST exact form in the large Hilbert space. We relate this approach to the description of vertical integration given by Sen and Witten.

  17. Plasmon Modes of Vertically Aligned Superlattices

    DEFF Research Database (Denmark)

    Filonenko, Konstantin; Duggen, Lars; Willatzen, Morten

    2017-01-01

    By using the Finite Element Method we visualize the modes of vertically aligned superlattice composed of gold and dielectric nanocylinders and investigate the emitter-plasmon interaction in approximation of weak coupling. We find that truncated vertically aligned superlattice can function as plas...

  18. A vertically resolved model for phytoplankton aggregation

    Indian Academy of Sciences (India)

    components undergo vertical mixing, and phytoplank- ton sink. Phytoplankton growth is limited by the product of nutrient and light terms. The equations for nitrate (NO3) and ... resolved model there is an extra complication: the largest particles that sink out of ...... and biogeochemistry with satellite ocean colour data. Vertically ...

  19. Plasmon Modes of Vertically Aligned Superlattices

    DEFF Research Database (Denmark)

    Filonenko, Konstantin; Duggen, Lars; Willatzen, Morten

    By using the Finite Element Method we visualize the modes of vertically aligned superlattice composed of gold and dielectric nanocylinders and investigate the emitter-plasmon interaction in approximation of weak coupling. We find that truncated vertically aligned superlattice can function as plas...

  20. DESIGN, CONSTRUCTION AND EVALUATION OF A VERTICAL ...

    African Journals Online (AJOL)

    Vertical plate metering device is intended to minimize seed damage during planting while improving metering efficiency and field capacity. A vertical plate maize seed planter which is adapted for gardens and small holder farmers cultivating less than two hectares has been designed, constructed and tested. The major ...

  1. The green building envelope : Vertical greening

    NARCIS (Netherlands)

    Ottelé, M.

    2011-01-01

    Planting on roofs and façades is one of the most innovative and fastest developing fields of green technologies with respect to the built environment and horticulture. This thesis is focused on vertical greening of structures and to the multi-scale benefits of vegetation. Vertical green can improve

  2. Vertical Integration, Monopoly, and the First Amendment.

    Science.gov (United States)

    Brennan, Timothy J.

    This paper addresses the relationship between the First Amendment, monopoly of transmission media, and vertical integration of transmission and content provision. A survey of some of the incentives a profit-maximizing transmission monopolist may have with respect to content is followed by a discussion of how vertical integration affects those…

  3. Autism Spectrum Disorder

    Centers for Disease Control (CDC) Podcasts

    2014-04-02

    This podcast discusses autism spectrum disorder (ASD), a developmental disability that causes problems with social, communication, and behavioral skills. CDC estimates that one in 68 children has been identified as having ASD.  Created: 4/2/2014 by National Center on Birth Defects and Developmental Disabilities (NCBDDD).   Date Released: 4/2/2014.

  4. Comparative study between astrogeodetic methods used in determining vertical deflection

    Science.gov (United States)

    Badescu, O.; Popescu, R.; Popescu, P.

    2006-10-01

    The determination of the geoid-ellipsoid relative position is one of the main tasks of geodesy. This can be performed by many methods but we tried to do by astronomical determination of the deviation of the vertical. In this sense we realized two sets of measurements one of them with an electronic total station (the method was already described in precedent articles of Journées) and another, for safety and comparisons, with a CCD astrolabe. The results show that the actual geodetic devices can be used with success to this type of works.

  5. Theory and observations of horizontal and vertical structure of gravity wave perturbations in the middle atmosphere

    Science.gov (United States)

    Hostetler, Chris Alan

    Gravity wave models for the horizontal wave number spectra of atmospheric velocity and density fluctuations are derived by assuming that both saturated and unsaturated waves obey the polarization and dispersion relations and that the joint (m,w) spectrum is separable. The models show that the joint (k,l,m) and (k,l,w) spectra are not separable. The one-dimensional horizontal wave number spectra models are consistent with existing observations of horizontal wave number spectra in the lower stratosphere and upper mesosphere. The gravity wave models are used to analyze the effects of Doppler shifting caused by the mean wind field on the separability of gravity wave spectra. If the intrinsic joint (m,w) spectrum is separable, Doppler effects associated with even small mean winds will destroy separability of the observed joint (m,w(sub o)) spectrum, particularly at high vertical wave numbers. Vertical and horizontal wave number spectra of density perturbations in the upper stratosphere (25-40 km) and the upper mesosphere (approximately 80-105 km) measured during the ALOHA-90 campaign are presented. The spectra were inferred from approximately 45 h of airborne Na/Rayleigh lidar observations in the vicinity of Hawaii. Density variances, vertical shear variances, Richardson's numbers, characteristic vertical and horizontal wave numbers, and power law slopes of the vertical and horizontal wave number spectra are computed and discussed. The observed m-spectra contradict the predictions of the linear instability theory of Dewan and Good, and the scale-dependent diffusive filtering theory of Gardner, and appear to be compatible with the Doppler spreading theory of Hines, the scale-dependent diffusion theory of Weinstock, the scale-independent diffusive filtering theory of Gardner, and the similitude model of Dewan. In the stratosphere, the m-spectra exhibit significant energy at low wave numbers less than the values expected for m(sub *). The source of this energy is believed

  6. Electronic structure and solvation of copper and silver ions: a theoretical picture of a model aqueous redox reaction.

    Science.gov (United States)

    Blumberger, Jochen; Bernasconi, Leonardo; Tavernelli, Ivano; Vuilleumier, Rodolphe; Sprik, Michiel

    2004-03-31

    Electronic states and solvation of Cu and Ag aqua ions are investigated by comparing the Cu(2+) + e(-)--> Cu(+) and Ag(2+) + e(-)--> Ag(+) redox reactions using density functional-based computational methods. The coordination number of aqueous Cu(2+) is found to fluctuate between 5 and 6 and reduces to 2 for Cu(+), which forms a tightly bound linear dihydrate. Reduction of Ag(2+) changes the coordination number from 5 to 4. The energetics of the oxidation reactions is analyzed by comparing vertical ionization potentials, relaxation energies, and vertical electron affinities. The model is validated by a computation of the free energy of the full redox reaction Ag(2+) + Cu(+) --> Ag(+) + Cu(2+). Investigation of the one-electron states shows that the redox active frontier orbitals are confined to the energy gap between occupied and empty states of the pure solvent and localized on the metal ion hydration complex. The effect of solvent fluctuations on the electronic states is highlighted in a computation of the UV absorption spectrum of Cu(+) and Ag(+).

  7. Experimental KLM + KLN Auger spectrum of Cu

    Energy Technology Data Exchange (ETDEWEB)

    Inoyatov, A.Kh., E-mail: inoyatov@jinr.ru [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Institute of Applied Physics, National University, Tashkent (Uzbekistan); Perevoshchikov, L.L. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Zhdanov, V.S. [Institute of Nuclear Physics, Almaty (Kazakhstan); Filosofov, D.V. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Kovalík, A. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Nuclear Physics Institute of the ASCR, Řež near Prague (Czech Republic)

    2013-08-15

    Highlights: •The KLM Auger spectrum of Cu was measured for the first time in detail. •Energies and relative intensities of nine resolved spectrum components were determined. •Semi-empirical KLM energy predictions and experiment agree mostly within 3σ with the exception of the transitions involving the M{sub 4,5} atomic subshells. •It was found that the KLM transition rates at Z = 29 should be calculated relativistically in intermediate coupling scheme. -- Abstract: The KLM + KLN Auger electron spectrum of Cu (Z = 29) emitted in the electron capture decay of radioactive {sup 65}Zn in a solid matrix was investigated for the first time using a combined electrostatic electron spectrometer adjusted to the 7 eV instrumental resolution. Energies and relative intensities of nine resolved spectrum components were determined and compared with theoretical expectations. An agreement within 3σ was found between the semi-empirical predictions for the KLM transition energies by Larkins and the experimental data with the exception of the weak (KL{sub 2}M{sub 4,5} + KL{sub 2}N{sub 1}) and (KL{sub 3}M{sub 4,5} + KL{sub 3}N{sub 1}) lines where the differences reached 5σ. From a comparison of the measured relative KLM transition intensities with available theoretical results a conclusion was derived that calculations of the KLM transition rates at Z = 29 should be based on intermediate coupling of angular momenta and take into account relativistic effects.

  8. Variations of n /sub e/h/ profiles and of vertical gradients at low latitudes during disturbances

    Energy Technology Data Exchange (ETDEWEB)

    Goncharova, E.E.; Zevakina, R.A.; Palacio, L.

    1979-11-01

    The paper examines the electron density height profile and vertical gradients of electron density distribution as a function of the type and phase of ionospheric disturbances on the basis of data from the Cuban geophysical center for 1968. The difference between low-latitude height variations of electron density and those at midlatitudes is investigated, and possible causes of electron density height variations at low latitudes are discussed.

  9. The distance spectrum of corona and cluster of two graphs

    Directory of Open Access Journals (Sweden)

    G. Indulal

    2015-11-01

    Full Text Available Let G be a connected graph with a distance matrix D. The D-eigenvalues {μ1,μ2,…,…,μp} of G are the eigenvalues of D and form the distance spectrum or D-spectrum of G. Given two graphs G with vertex set {v1,v2,……,vp} and H, the corona G∘H is defined as the graph obtained by taking p copies of H and for each i, joining the ith vertex of G to all the vertices in the ith copy of H. Let H be a rooted graph rooted at u. Then the cluster G{H} is defined as the graph obtained by taking p copies of H and for each i, joining the ith vertex of G to the root in the ith copy of H. In this paper we describe the distance spectrum of G∘H, for a connected distance regular graph G and any r-regular graph H in terms of the distance spectrum of G and adjacency spectrum of H. We also describe the distance spectrum of G{Kn}, where G is a connected distance regular graph.

  10. Adaptive spectrum decision framework for heterogeneous dynamic spectrum access networks

    CSIR Research Space (South Africa)

    Masonta, M

    2015-09-01

    Full Text Available Spectrum decision is the ability of a cognitive radio (CR) system to select the best available spectrum band to satisfy dynamic spectrum access network (DSAN) users¿ quality of service (QoS) requirements without causing harmful interference...

  11. On the nonlinear shaping mechanism for gravity wave spectrum in the atmosphere

    Directory of Open Access Journals (Sweden)

    I. P. Chunchuzov

    2009-11-01

    Full Text Available The nonlinear mechanism of shaping of a high vertical wave number spectral tail in the field of a few discrete internal gravity waves in the atmosphere is studied in this paper. The effects of advection of fluid parcels by interacting gravity waves are taken strictly into account by calculating wave field in Lagrangian variables, and performing a variable transformation from Lagrangian to Eulerian frame. The vertical profiles and vertical wave number spectra of the Eulerian displacement field are obtained for both the case of resonant and non-resonant wave-wave interactions. The evolution of these spectra with growing parameter of nonlinearity of the internal wave field is studied and compared to that of a broad band spectrum of gravity waves with randomly independent amplitudes and phases. The calculated vertical wave number spectra of the vertical displacements or relative temperature fluctuations are found to be consistent with the observed spectra in the middle atmosphere.

  12. Reduced oblique effect in children with Autism Spectrum Disorders (ASD

    Directory of Open Access Journals (Sweden)

    Olga V Sysoeva

    2016-01-01

    Full Text Available People are very precise in the discrimination of a line orientation relative to the cardinal (verti-cal and horizontal axes, while their orientation discrimination sensitivity along the oblique ax-es is less refined. This difference in discrimination sensitivity along cardinal and oblique axes is called the oblique effect. Given that the oblique effect is a basic feature of visual pro-cessing with an early developmental origin, its investigation in children with Autism Spectrum Disorder (ASD may shed light on the nature of visual sensory abnormalities frequently report-ed in this population. We examined line orientation sensitivity along oblique and vertical axes in a sample of 26 boys with ASD (IQ > 68 and 38 typically developing (TD boys aged 7-15 years, as well as in a subsample of carefully IQ-matched ASD and TD participants. Children were asked to detect the direction of tilt of a high-contrast black-and-white grating relative to vertical (90° or oblique (45° templates. The oblique effect was reduced in children with ASD as compared to TD participants, irrespective of their IQ. This reduction was due to poor orien-tation sensitivity along vertical axis in ASD children, while their ability to discriminate line orientation along oblique axis was unaffected. We speculate that this deficit in sensitivity to vertical orientation may reflect disrupted mechanisms of early experience-dependent learning that takes place during the critical period for orientation selectivity.

  13. Reduced Oblique Effect in Children with Autism Spectrum Disorders (ASD)

    Science.gov (United States)

    Sysoeva, Olga V.; Davletshina, Maria A.; Orekhova, Elena V.; Galuta, Ilia A.; Stroganova, Tatiana A.

    2016-01-01

    People are very precise in the discrimination of a line orientation relative to the cardinal (vertical and horizontal) axes, while their orientation discrimination sensitivity along the oblique axes is less refined. This difference in discrimination sensitivity along cardinal and oblique axes is called the “oblique effect.” Given that the oblique effect is a basic feature of visual processing with an early developmental origin, its investigation in children with Autism Spectrum Disorder (ASD) may shed light on the nature of visual sensory abnormalities frequently reported in this population. We examined line orientation sensitivity along oblique and vertical axes in a sample of 26 boys with ASD (IQ > 68) and 38 typically developing (TD) boys aged 7–15 years, as well as in a subsample of carefully IQ-matched ASD and TD participants. Children were asked to detect the direction of tilt of a high-contrast black-and-white grating relative to vertical (90°) or oblique (45°) templates. The oblique effect was reduced in children with ASD as compared to TD participants, irrespective of their IQ. This reduction was due to poor orientation sensitivity along the vertical axis in ASD children, while their ability to discriminate line orientation along the oblique axis was unaffected. We speculate that this deficit in sensitivity to vertical orientation may reflect disrupted mechanisms of early experience-dependent learning that takes place during the critical period for orientation selectivity. PMID:26834540

  14. Measurement of a small vertical emittance with a laser wire beam profile monitor

    Directory of Open Access Journals (Sweden)

    Hiroshi Sakai

    2002-12-01

    Full Text Available We describe in this paper a measurement of vertical emittance in the Accelerator Test Facility (ATF damping ring at KEK with a laser wire beam profile monitor. This monitor is based on the Compton scattering process of electrons with a laser light target which is produced by injecting a cw laser beam into a Fabry-Perot optical cavity. We installed the monitor at a straight section of the damping ring and measured the vertical emittance with three different ring conditions. In all cases, the ATF ring was operated at 1.28 GeV in a single bunch mode. When the ring was tuned for ultralow emittance, the vertical emittance of ε_{y}=(1.18±0.08×10^{-11}   mrad was achieved. This shows that the ATF damping ring has realized its target value also vertically.

  15. Electrooptic approach to an integrated optics spectrum analyzer.

    Science.gov (United States)

    Thylen, L; Stensland, L

    1981-05-15

    An integrated optics spectrum analyzer based on using the linear electrooptic effect is investigated. This spectrum analyzer performs Fourier analysis of sampled electronic signals, where each signal is fed to an electrode of an electrode array. The electrode array acts as a spatial light modulator, and the diffracted light field, representing a weighted discrete Fourier transform (DFT), is focused on a detector array by an integrated transform lens. The theory of operation of the spectrum analyzer is outlined, numerical results relating to this theory are presented, and questions concerning efficiency, dynamic range, design, and implementation are discussed.

  16. Unconventional vertical word-order impairs reading.

    Science.gov (United States)

    Bonfiglioli, Claudia

    2011-01-01

    Western written languages unfold across both the horizontal (from left to right) and the vertical (from top to bottom) dimensions. Culturally determined horizontal reading/writing habits are so pervasive that their influence can be found not only in visual scanning but also in performance across different domains and tasks. However, little is known on the effects of vertical word order. In the present study, a lexical decision task is used to show that reading performance is less efficient when verbal material is vertically arranged following a bottom-to-top order.

  17. Surface tension profiles in vertical soap films

    Science.gov (United States)

    Adami, N.; Caps, H.

    2015-01-01

    Surface tension profiles in vertical soap films are experimentally investigated. Measurements are performed by introducing deformable elastic objets in the films. The shape adopted by those objects once set in the film is related to the surface tension value at a given vertical position by numerically solving the adapted elasticity equations. We show that the observed dependency of the surface tension versus the vertical position is predicted by simple modeling that takes into account the mechanical equilibrium of the films coupled to previous thickness measurements.

  18. A novel classification of frontal bone fractures: The prognostic significance of vertical fracture trajectory and skull base extension.

    Science.gov (United States)

    Garg, Ravi K; Afifi, Ahmed M; Gassner, Jennifer; Hartman, Michael J; Leverson, Glen; King, Timothy W; Bentz, Michael L; Gentry, Lindell R

    2015-05-01

    The broad spectrum of frontal bone fractures, including those with orbital and skull base extension, is poorly understood. We propose a novel classification scheme for frontal bone fractures. Maxillofacial CT scans of trauma patients were reviewed over a five year period, and frontal bone fractures were classified: Type 1: Frontal sinus fracture without vertical extension. Type 2: Vertical fracture through the orbit without frontal sinus involvement. Type 3: Vertical fracture through the frontal sinus without orbit involvement. Type 4: Vertical fracture through the frontal sinus and ipsilateral orbit. Type 5: Vertical fracture through the frontal sinus and contralateral or bilateral orbits. We also identified the depth of skull base extension, and performed a chart review to identify associated complications. 149 frontal bone fractures, including 51 non-vertical frontal sinus (Type 1, 34.2%) and 98 vertical (Types 2-5, 65.8%) fractures were identified. Vertical fractures penetrated the middle or posterior cranial fossa significantly more often than non-vertical fractures (62.2 v. 15.7%, p = 0.0001) and had a significantly higher mortality rate (18.4 v. 0%, p fractures with frontal sinus and orbital extension, and fractures that penetrated the middle or posterior cranial fossa had the strongest association with intracranial injuries, optic neuropathy, disability, and death (p bone fractures carry a worse prognosis than frontal bone fractures without a vertical pattern. In addition, vertical fractures with extension into the frontal sinus and orbit, or with extension into the middle or posterior cranial fossa have the highest complication rate and mortality. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  19. Raman spectrum of asphaltene

    KAUST Repository

    Abdallah, Wael A.

    2012-11-05

    Asphaltenes extracted from seven different crude oils representing different geological formations from around the globe were analyzed using the Raman spectroscopic technique. Each spectrum is fitted with four main peaks using the Gaussian function. On the basis of D1 and G bands of the Raman spectrum, asphaltene indicated an ordered structure with the presence of boundary defected edges. The average aromatic sheet size of the asphaltene molecules is estimated within the range of 1.52-1.88 nm, which represents approximately seven to eight aromatic fused rings. This estimation is based on the integrated intensity of D1 and G bands, as proposed by Tunistra and Koenig. The results here are in perfect agreement with so many other used techniques and indicate the potential applicability of Raman measurements to determine the average aromatic ring size and its boundary. © 2012 American Chemical Society.

  20. Radio frequency spectrum management

    Science.gov (United States)

    Sujdak, E. J., Jr.

    1980-03-01

    This thesis is a study of radio frequency spectrum management as practiced by agencies and departments of the Federal Government. After a brief introduction to the international agency involved in radio frequency spectrum management, the author concentrates on Federal agencies engaged in frequency management. These agencies include the National Telecommunications and Information Administration (NTIA), the Interdepartment Radio Advisory Committee (IRAC), and the Department of Defense (DoD). Based on an analysis of Department of Defense frequency assignment procedures, recommendations are given concerning decentralizing military frequency assignment by delegating broader authority to unified commanders. This proposal includes a recommendation to colocate the individual Service frequency management offices at the Washington level. This would result in reduced travel costs, lower manpower requirements, and a common tri-Service frequency management data base.

  1. Spectrum Utilization Concepts

    Science.gov (United States)

    1988-11-30

    bands and space services since it accounts for carrier types , modulation and multiple access techniques, and regenerative repeaters that are not... TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Yeaw, Mont, Day) 15. PAGE COUNT Final FROM Dec87 TO Nov 88 1988 November 30 240 16. SUPPLEMENTARY...MILSATCOM, WARC, Spectrum Use 19,ABSTRACT (Continue on reverse it necessary and Identify by blod number) The objective of this task was to provide

  2. AUTISM SPECTRUM DISORDERS (ASD)

    OpenAIRE

    Middha Akanksha; Kataria Sahil; Sandhu Premjeet; Kapoor Bhawna

    2011-01-01

    Autism or Autism Spectrum Disorders (ASD) is a serious neurological disorder affecting communication skills, social interactions, adaptability in an individual, and also causes dramatic changes in behavioral patterns. This condition typically lasts throughout one’s lifetime and affects both, children as well as adults. Research has shown a tenfold increase in autism cases over the past decade and still rising at an alarming pace. The origins of autism are not known even to modern science. Aut...

  3. Electron and Photon ID

    CERN Document Server

    Hryn'ova, Tetiana; The ATLAS collaboration

    2017-01-01

    The identification of prompt photons and the rejection of background coming mostly from photons from hadron decays relies on the high granularity of the ATLAS calorimeter. The electron identification used in ATLAS for run 2 is based on a likelihood discrimination to separate isolated electron candidates from candidates originating from photon conversions, hadron misidentification and heavy flavor decays. In addition, isolation variables are used as further handles to separate signal and background. Several methods are used to measure with data the efficiency of the photon identification requirements, to cover a broad energy spectrum. At low energy, photons from radiative Z decays are used. In the medium energy range, similarities between electrons and photon showers are exploited using Z->ee decays. At high energy, inclusive photon samples are used. The measurement of the efficiencies of the electron identification and isolation cuts are performed with the data using tag and probe techniques with large statis...

  4. The Electron

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, George

    1972-01-01

    Electrons are elementary particles of atoms that revolve around and outside the nucleus and have a negative charge. This booklet discusses how electrons relate to electricity, some applications of electrons, electrons as waves, electrons in atoms and solids, the electron microscope, among other things.

  5. Carbon Nanotube Electron Sources for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation proposed here focuses on cleansing air with high energy electrons. Bombardment by electrons has proven to be effective in removing a wide spectrum of...

  6. Carbon Micronymphaea: Graphene on Vertically Aligned Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Jong Won Choi

    2013-01-01

    Full Text Available This paper describes the morphology of carbon nanomaterials such as carbon nanotube (CNT, graphene, and their hybrid structure under various operating conditions during a one-step synthesis via plasma-enhanced chemical vapor deposition (PECVD. We focus on the synthetic aspects of carbon hybrid material composed of heteroepitaxially grown graphene on top of a vertical array of carbon nanotubes, called carbon micronymphaea. We characterize the structural features of this unique nanocomposite by uses of electron microscopy and micro-Raman spectroscopy. We observe carbon nanofibers, poorly aligned and well-aligned vertical arrays of CNT sequentially as the growth temperature increases, while we always discover the carbon hybrids, called carbon micronymphaea, at specific cooling rate of 15°C/s, which is optimal for the carbon precipitation from the Ni nanoparticles in this study. We expect one-pot synthesized graphene-on-nanotube hybrid structure poses great potential for applications that demand ultrahigh surface-to-volume ratios with intact graphitic nature and directional electronic and thermal transports.

  7. Vertical vergence adaptation produces an objective vertical deviation that changes with head tilt.

    Science.gov (United States)

    Irsch, Kristina; Guyton, David L; Ramey, Nicholas A; Adyanthaya, Rohit S; Ying, Howard S

    2013-05-03

    To document the cyclovertical ocular motor mechanism used for vertical fusion in healthy subjects, and to explore whether vertical vergence training in healthy individuals can produce objectively confirmed vertical deviations that change with head tilt, revealing a basic mechanism that can produce a pattern of misalignment in an otherwise normal ocular motor system that is similar to superior oblique muscle paresis (SOP). Seven subjects with normal orthoptic examinations were adapted to vertical image disparities using our tilting haploscopic eye-tracking apparatus presenting concentric circle targets without torsional cues. Static eye positions were recorded with head straight and when tilted 45 degrees to the left and right, during both binocular and monocular viewing. Vertical fusional vergence was accompanied by a cycloversion, with the downward-moving eye intorting and the upward-moving eye extorting, implicating primary involvement of the oblique extraocular muscles. After adaptation to the slowly increasing vertical target separation, all subjects developed a temporary vertical deviation in the straight ahead position that increased with head tilt to one side and decreased with head tilt to the other side. These results not only show that head-tilt-dependent changes in vertical deviation are not necessarily pathognomonic for SOP, but also, and more importantly, suggest mechanisms that can mimic SOP and suggest a possible role for vertical vergence training in reducing deviations and thus the amount of head tilt required for fusion. Ultimately, vertical vergence training may provide an adjunct or alternative to extraocular muscle surgery in selected cases.

  8. Copper vertical micro dendrite fin arrays and their superior boiling heat transfer capability

    Science.gov (United States)

    Wang, Ya-Qiao; Lyu, Shu-Shen; Luo, Jia-Li; Luo, Zhi-Yong; Fu, Yuan-Xiang; Heng, Yi; Zhang, Jian-Hui; Mo, Dong-Chuan

    2017-11-01

    Micro pin fin arrays have been widely used in electronic cooling, micro reactors, catalyst support, and wettability modification and so on, and a facile way to produce better micro pin fin arrays is demanded. Herein, a simple electrochemical method has been developed to fabricate copper vertical micro dendrite fin arrays (Cu-VMDFA) with controllable shapes, number density and height. High copper sulphate concentration is one key point to make the dendrite stand vertically. Besides, the applied current should rise at an appropriate rate to ensure the copper dendrite can grow vertically on its own. The Cu-VMDFA can significantly enhance the heat transfer coefficient by approximately twice compared to the plain copper surface. The Cu-VMDFA may be widely used in boiling heat transfer areas such as nuclear power plants, electronic cooling, heat exchangers, and so on.

  9. Spectrum Services 2007

    Science.gov (United States)

    Dobos, L.; Budavári, T.; Csabai, I.; Szalay, A. S.

    2008-10-01

    We present the Filter and Spectrum Services consisting of easy-to-use web applications and web services for searching, plotting and managing large collections of spectral energy distribution data and filter profiles as well as for performing various scientific operations on spectra in a unified framework. The services provide keyword search, advanced query forms and SQL query possibilities for selecting spectra or bandpass curves which may be retrieved in a variety of file formats including XML, VOTable and ASCII. All SDSS DR1-DR5 spectra had been loaded into a database as well as the entire 2dF catalog that adds up to more than 2.5 million SEDs of about a million spatial objects, but registered users can upload their own data making it available for the rest of the community and are free to modify or delete them at any time. Theoretical catalogs, such as the Bruzual-Charlot stochastic burst model spectrum library (100k spectra) and the BaSeL stellar library are also available. Scientific services allow building rest-frame composite spectra out of selected spectra; calculating synthetic magnitudes by convolving spectra with an arbitrary set of bandpass curves of optical instrument filters to generate simulated photometric catalogs on-the-fly; galactic extinction correction, fitting of the continuum using different set of templates (Bruzual-Charlot '03 templates, SDSS eigenspectra), line fitting. All scientific functionalities are available from the web user interface and via the SOAP web services for programmers. MySpectrum is a cross-platform version of the spectrum web service for setting up your own spectrum repository. It integrates into the main service allowing easy access to your data for the whole VO community. The main idea behind our web services is to move scientific functionalities physically close to the database in order to spare network bandwidth. This way scientists may do research without setting up expensive hardware, downloading large datasets

  10. METAL CHELATING AGENTS IV: ELECTRON IONIZATION AND ...

    African Journals Online (AJOL)

    The electron ionization (EI) and ammonia chemical ionization [CI (NH3)] mass spectral studies on 2-phenyl acetophenone semicarbazone are reported. The El spectrum shows a clearly identifiable molecular ion peak of weak intensity at m/z 253 and the base peak is observed at m/z 77. The CI (NH3) spectrum is ...

  11. HL-LHC vertical cryostat during construction

    CERN Multimedia

    Lanaro, Andrea

    2016-01-01

    7m high "Cluster D" vertical test cryostat during construction at contractor's premises, Alca Technology Srl, in Schio, Italy. The inner helium vessel with its heat exchanger are visible. To be installed in the D pit in SMA18.

  12. Thermal vertical bimorph actuators and their applications

    CERN Document Server

    Sehr, H J

    2002-01-01

    In this thesis, a novel concept for lateral actuators based on vertical bimorphs is presented. Vertical bimorphs consist of silicon beams side-coated with aluminium, which bend when heated due to the different thermal expansion coefficients of the two materials causing a displacement in the wafer plane. The heating of the actuator is provided by an electrical current through the silicon beam. The simplest implementation of a vertical bimorph actuator is a clamped-clamped beam. To obtain higher deflections, a meander shaped actuator has been designed. By combining four meander actuators, a two-dimensional positioning stage has been realised. The meander actuator has also been applied for normally closed and normally open micro-relays. Analytical calculations and ANSYS simulations have been carried out to predict the physical behaviour of the bimorph devices, including temperature distribution, static deflection, vertical stiffness, thermal time constant and lateral resonances. For both the clamped-clamped beam...

  13. Multiloop string vertices from the path integral

    Energy Technology Data Exchange (ETDEWEB)

    Bochicchio, M.; Lerda, A.

    1989-02-02

    We derive the multiloop vertices for the bosonic string using path integral methods and establish a precise equivalence between the functional approach to string perturbation theory and the operator formalism on Riemann surfaces recently developed by various authors.

  14. Vertical Land Change, Perry County, Kentucky

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The vertical land change activity focuses on the detection, analysis, and explanation of topographic change. These detection techniques include both quantitative...

  15. Management information systems for electronic warfare command and decision support

    CSIR Research Space (South Africa)

    Van Niekerk, B

    2015-04-01

    Full Text Available information to allow them to manage their own spectrum, to identify threats, and to deny adversaries’ use of the spectrum. In this paper, the concepts of integrated electronic warfare and spectrum battle management are introduced, and the relevant information...

  16. Probing plasmonic nanostructures by photons and electrons

    DEFF Research Database (Denmark)

    Kneipp, Katrin; Kneipp, Harald; Kneipp, Janina

    2015-01-01

    We discuss recent developments for studying plasmonic metal nanostructures. Exploiting photons and electrons opens up new capabilities to probe the complete plasmon spectrum including bright and dark modes and related local optical fields at subnanometer spatial resolution. This comprehensive...

  17. A Computational Framework for Vertical Video Editing

    OpenAIRE

    Gandhi, Vineet; Ronfard, Rémi

    2015-01-01

    International audience; Vertical video editing is the process of digitally editing the image within the frame as opposed to horizontal video editing, which arranges the shots along a timeline. Vertical editing can be a time-consuming and error-prone process when using manual key-framing and simple interpolation. In this paper, we present a general framework for automatically computing a variety of cinematically plausible shots from a single input video suitable to the special case of live per...

  18. Updated Vertical Extent of Collision Damage

    DEFF Research Database (Denmark)

    Tagg, R.; Bartzis, P.; Papanikolaou, P.

    2002-01-01

    The probabilistic distribution of the vertical extent of collision damage is an important and somewhat controversial component of the proposed IMO harmonized damage stability regulations for cargo and passenger ships. The only pre-existing vertical distribution, currently used in the international...... cargo ship regulations, was based on a very simplified presumption of bow heights. This paper investigates the development of this damage extent distribution based on three independent methodologies; actual casualty measurements, world fleet bow height statistics, and collision simulation modeling...

  19. Vertical Jump: Biomechanical Analysis and Simulation Study

    OpenAIRE

    Babic, Jan; Lenarcic, Jadran

    2007-01-01

    By building an efficient biorobotic model which includes an elastic model of the biarticular muscle gastrocnemius and by simulation of the vertical jump we have demonstrated that biarticular links contribute a great deal to the performance of the vertical jump. Besides, we have shown that timing of the biarticular link activation and stiffness of the biarticular link considerably influence the height of the jump. Methodology and results of our study offer an effective tool for the design of t...

  20. VERTIC SOILS IN CODRY REGIONS OF MOLDOVA

    Directory of Open Access Journals (Sweden)

    A. Ursu

    2009-10-01

    Full Text Available The features of structure of some parent materials essentially influence of direction of pedogenesis, cause the processes of lithomorphism. On heavy tertiary clays in different conditionsare formed the special genetic type (vertisols or transitive to lithomorphic subtype of zonal soil (vertic soil. In article the characteristic of vertisols (the subtype of mollic and ochric and thesubtypes of vertic chernozems and grey soils is given.

  1. Vertical zonality of septal nectaries of Monocots

    Directory of Open Access Journals (Sweden)

    Аnastasiya Odintsova

    2013-04-01

    Full Text Available Considering the septal nectary as a system of exogenous cavities inside the ovary and taking account of possibilities of various ways of the formation of nectary walls we propose to apply the concept of vertical zonality to the analysis of the septal nectary structure. The comparative analysis of the gynoecium with septal nectaries must include data about the nectary vertical zones and its location in the structural zones of the gynoecium.

  2. Advanced Si solid phase crystallization for vertical channel in vertical NANDs

    Directory of Open Access Journals (Sweden)

    Sangsoo Lee

    2014-07-01

    Full Text Available The advanced solid phase crystallization (SPC method using the SiGe/Si bi-layer structure is proposed to obtain high-mobility poly-Si thin-film transistors in next generation vertical NAND (VNAND devices. During the SPC process, the top SiGe thin film acts as a selective nucleation layer to induce surface nucleation and equiaxial microstructure. Subsequently, this SiGe thin film microstructure is propagated to the underlying Si thin film by epitaxy-like growth. The initial nucleation at the SiGe surface was clearly observed by in situ transmission electron microscopy (TEM when heating up to 600 °C. The equiaxial microstructures of both SiGe nucleation and Si channel layers were shown in the crystallized bi-layer plan-view TEM measurements. Based on these experimental results, the large-grained and less-defective Si microstructure is expected to form near the channel region of each VNAND cell transistor, which may improve the electrical characteristics.

  3. Effects of hydrostatic pressure and temperature on the electron paramagnetic resonance spectrum of off-centre Jahn-Teller [CuF sub 4 F sub 4] sup 6 sup - complexes in SrF sub 2 crystal

    CERN Document Server

    Ulanov, V A; Hoffmann, S K; Zaripov, M M

    2003-01-01

    Pressure and temperature variations of the spin-Hamiltonian parameters and electron paramagnetic resonance (EPR) linewidths of non-central Jahn-Teller [CuF sub 4 F sub 4] sup 6 sup - complexes in SrF sub 2 crystal were studied by continuous-wave EPR. It was found that the static spin-Hamiltonian parameters, found at T = 85 K and at normal pressure (g sub | sub | = 2.491, g sub p sub e sub r sub p sub e sub n sub d sub i sub c sub u sub l sub a sub r = 2.083, a sub p sub a sub r sub a sub l sub l sub e sub l = 360, a sub p sub e sub r sub p sub e sub n sub d sub i sub c sub u sub l sub a sub r = 26, A sub x sub ' sub ' = 96, A sub y sub ' sub ' = 99, A sub z sub ' sub ' = 403 and beta sub e sub x sub p = 17 diameter), are slightly changed with hydrostatic pressure and, at T = 85 K and P = 550 MPa, become equal to g sub | sub | = 2.489, g sub p sub e sub r sub p sub e sub n sub d sub i sub c sub u sub l sub a sub r = 2.083, a sub | sub | 348, a sub p sub e sub r sub p sub e sub n sub d sub i sub c sub u sub l s...

  4. A Study of Vertical Transport through Graphene towards Control of Quantum Tunneling.

    Science.gov (United States)

    Zhu, Xiaodan; Lei, Sidong; Tsai, Shin-Hung; Zhang, Xiang; Liu, Jun; Yin, Gen; Tang, Min; Torres, Carlos Manuel; Navabi, Aryan; Jin, Zehua; Tsai, Shiao-Po; Qasem, Hussam; Wang, Yong; Vajtai, Robert; Lake, Roger K; Ajayan, Pulickel M; Wang, Kang L

    2018-01-04

    Vertical integration of van der Waals (vdW) materials with atomic precision is an intriguing possibility brought forward by these 2-dimensional materials. Essential to the design and analysis of these structures is a fundamental understanding of the vertical transport of charge carriers into and across vdW materials, yet little has been done in this area. In this report, we explore the important roles of single layer graphene in the vertical tunneling process as a tunneling barrier. Although a semi-metal in the lateral lattice plane, graphene together with the vdW gap act as a tunneling barrier that is nearly transparent to the vertically tunneling electrons due to its atomic thickness and the transverse momenta mismatch between the injected electrons and the graphene band structure. This is accentuated using electron tunneling spectroscopy (ETS) showing a lack of features corresponding to the Dirac cone band structure. Meanwhile, the graphene acts as a lateral conductor through which the potential and charge distribution across the tunneling barrier can be tuned. These unique properties make graphene an excellent 2-dimensional atomic grid, transparent to charge carriers, and yet can control the carrier flux via the electrical potential. A new model on the quantum capacitance's effect on vertical tunneling is developed to further elucidate the role of graphene in modulating the tunneling process. This work may serve as a general guideline for the design and analysis of vdW vertical tunneling devices and heterostructures, as well as the study of electron/spin injection through and into vdW materials.

  5. A spatially indirect exciton in vertically coupled quantum dots : 1/Q-expansion

    NARCIS (Netherlands)

    Lozovik, YE; Mur, VD; Narozhny, NB; Petrosyan, AN

    A spatially indirect exciton in vertically coupled quantum dots is considered with the use of 1/Q-expansion, where Q is the dimensionless quantum parameter determined by the ratio of characteristic Coulomb energy of electron-hole interaction to the energy of one-particle transition in a confining

  6. Integrated Optoelectronic Probe Including a Vertical Cavity Surface Emitting Laser for Laser Doppler Perfusion Monitoring

    NARCIS (Netherlands)

    Serov, A.N.; Nieland, J.; Oosterbaan, S.; Steenbergen, W.; Bekman, H.H.P.T.; Mul, F.F.M. de; Kranenburg, H. van

    2006-01-01

    An integrated optoelectronic probe with small dimensions, for direct-contact laser Doppler blood flow monitoring has been realized. A vertical cavity surface emitting laser (VCSEL), and a chip with photodetectors and all necessary electronics are integrated in a miniature probe head connected to a

  7. Integrated optoelectronic probe including a vertical cavity surface emitting laser for laser Doppler perfusion monitoring

    NARCIS (Netherlands)

    Serov, Alexander; Nieland, Janharm; Nieland, J.; Oosterbaan, Sjoerd; de Mul, F.F.M.; van Kranenburg, H.; Bekman, Herman H.P.Th.; Steenbergen, Wiendelt

    2006-01-01

    An integrated optoelectronic probe with small dimensions, for direct-contact laser Doppler blood flow monitoring has been realized. A vertical cavity surface emitting laser (VCSEL), and a chip with photodetectors and all necessary electronics are integrated in a miniature probe head connected to a

  8. Modeling the QBO-Improvements resulting from higher-model vertical resolution.

    Science.gov (United States)

    Geller, Marvin A; Zhou, Tiehan; Shindell, D; Ruedy, R; Aleinov, I; Nazarenko, L; Tausnev, N L; Kelley, M; Sun, S; Cheng, Y; Field, R D; Faluvegi, G

    2016-09-01

    Using the NASA Goddard Institute for Space Studies (GISS) climate model, it is shown that with proper choice of the gravity wave momentum flux entering the stratosphere and relatively fine vertical layering of at least 500 m in the upper troposphere-lower stratosphere (UTLS), a realistic stratospheric quasi-biennial oscillation (QBO) is modeled with the proper period, amplitude, and structure down to tropopause levels. It is furthermore shown that the specified gravity wave momentum flux controls the QBO period whereas the width of the gravity wave momentum flux phase speed spectrum controls the QBO amplitude. Fine vertical layering is required for the proper downward extension to tropopause levels as this permits wave-mean flow interactions in the UTLS region to be resolved in the model. When vertical resolution is increased from 1000 to 500 m, the modeled QBO modulation of the tropical tropopause temperatures increasingly approach that from observations, and the "tape recorder" of stratospheric water vapor also approaches the observed. The transport characteristics of our GISS models are assessed using age-of-air and N2O diagnostics, and it is shown that some of the deficiencies in model transport that have been noted in previous GISS models are greatly improved for all of our tested model vertical resolutions. More realistic tropical-extratropical transport isolation, commonly referred to as the "tropical pipe," results from the finer vertical model layering required to generate a realistic QBO.

  9. Current Noise Spectrum of a Quantum Shuttle

    DEFF Research Database (Denmark)

    Flindt, Christian; Novotny, T.; Jauho, Antti-Pekka

    2005-01-01

    peaks at integer multiples of the mechanical frequency, which is slightly renormalized. The renormalization explains a previously observed small deviation of the shuttle Current compared to the expected value given by the product of the natural mechanical frequency and the electron charge. For a certain......We present a method for calculating the full current noise spectrum S(omega) for the class of nano-electromechanical systems (NEMS) that can be described by a Markovian generalized master equation. As a specific example we apply the method to a quantum shuttle. The noise spectrum of the shuttle has...... parameter range the quantum shuttle exhibits a coexistence regime, where the charges are transported by two different mechanisms: Shuttling and sequential tunneling. In our previous studies we showed that characteristic features in the zero-frequency noise could be quantitatively understood as a slow...

  10. Vertical Movements, Behavior and Habitat Utilization of Adult Yellowfin Tuna (Thunnus albacares) Tagged in West Philippine Sea, Mindoro Island, Philippines

    NARCIS (Netherlands)

    Macusi, Edison; Babaran, R.P.; Ingles, J.T.

    2015-01-01

    This paper describes the vertical movements, behavior and habitat utilization of an electronically tagged adult yellowfin tuna (Thunnus albacares) after 17 days of liberty in the Philippines based on analyses of 23,845 datapoints recorded from a recovered electronic popup tag. The exhaustive set

  11. Electron radiography

    Science.gov (United States)

    Merrill, Frank E.; Morris, Christopher

    2005-05-17

    A system capable of performing radiography using a beam of electrons. Diffuser means receive a beam of electrons and diffuse the electrons before they enter first matching quadrupoles where the diffused electrons are focused prior to the diffused electrons entering an object. First imaging quadrupoles receive the focused diffused electrons after the focused diffused electrons have been scattered by the object for focusing the scattered electrons. Collimator means receive the scattered electrons and remove scattered electrons that have scattered to large angles. Second imaging quadrupoles receive the collimated scattered electrons and refocus the collimated scattered electrons and map the focused collimated scattered electrons to transverse locations on an image plane representative of the electrons' positions in the object.

  12. Vertically coupled double quantum rings at zero magnetic field

    Science.gov (United States)

    Malet, F.; Barranco, M.; Lipparini, E.; Mayol, R.; Pi, M.; Climente, J. I.; Planelles, J.

    2006-06-01

    Within local-spin-density functional theory, we have investigated the “dissociation” of few-electron circular vertical semiconductor double quantum ring artificial molecules at zero magnetic field as a function of inter-ring distance. In a first step, the molecules are constituted by two identical quantum rings. When the rings are quantum mechanically strongly coupled, the electronic states are substantially delocalized, and the addition energy spectra of the artificial molecule resemble those of a single quantum ring in the few-electron limit. When the rings are quantum mechanically weakly coupled, the electronic states in the molecule are substantially localized in one ring or the other, although the rings can be electrostatically coupled. The effect of a slight mismatch introduced in the molecules from nominally identical quantum wells, or from changes in the inner radius of the constituent rings, induces localization by offsetting the energy levels in the quantum rings. This plays a crucial role in the appearance of the addition spectra as a function of coupling strength particularly in the weak coupling limit.

  13. Scalable transfer of vertical graphene nanosheets for flexible supercapacitor applications

    Science.gov (United States)

    Sahoo, Gopinath; Ghosh, Subrata; Polaki, S. R.; Mathews, Tom; Kamruddin, M.

    2017-10-01

    Vertical graphene nanosheets (VGN) are the material of choice for application in next-generation electronic devices. The growing demand for VGN-based flexible devices for the electronics industry brings in restriction on VGN growth temperature. The difficulty associated with the direct growth of VGN on flexible substrates can be overcome by adopting an effective strategy of transferring the well-grown VGN onto arbitrary flexible substrates through a soft chemistry route. In the present study, we report an inexpensive and scalable technique for the polymer-free transfer of VGN onto arbitrary substrates without disrupting its morphology, structure, and properties. After transfer, the morphology, chemical structure, and electrical properties are analyzed by scanning electron microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, and four-probe resistive methods, respectively. The wetting properties are studied from the water contact angle measurements. The observed results indicate the retention of morphology, surface chemistry, structure, and electronic properties. Furthermore, the storage capacity of the transferred VGN-based binder-free and current collector-free flexible symmetric supercapacitor device is studied. A very low sheet resistance of 670 Ω/□ and excellent supercapacitance of 158 μF cm-2 with 86% retention after 10 000 cycles show the prospect of the damage-free VGN transfer approach for the fabrication of flexible nanoelectronic devices.

  14. Vertical p-type Cu-doped ZnO/n-type ZnO homojunction nanowire-based ultraviolet photodetector by the furnace system with hotwire assistance.

    Science.gov (United States)

    Hsu, Cheng-Liang; Gao, Yi-Dian; Chen, You-Syuan; Hsueh, Ting-Jen

    2014-03-26

    Vertical p-ZnO:Cu/n-ZnO homojunction nanowires (NWs) and whole ZnO:Cu NWs were synthesized on a ZnO thin film/glass substrate by a furnace at 600 °C with 1700 °C hotwire assistance. According to the ZnO:Cu NW investigation, the energy-dispersive X-ray (EDX) spectrum indicates that the Cu content is 3.01 atomic %. The X-ray diffraction (XRD) peaks of ZnO:Cu NWs shift toward larger angles with increasing amounts of doped Cu. The Cu dopant enhanced the photoluminescence (PL) green-band peak and decreased the conductivity of the NWs, as measured by I-V. The gas sensing measurement and Hall effect verified that all ZnO:Cu NWs were p-type. In this study, transmission electron microscopy (TEM) and EDX mapping images revealed that the majority of the Cu element is located at the top of the p-ZnO:Cu/n-ZnO NW. The high-resolution transmission electron microscopy (HRTEM) image of the p-ZnO:Cu region shows that the NWs are [0001] growth-oriented, with lateral surfaces enclosed by (1̅101) planes. The I-V curve of p-ZnO:Cu/n-ZnO NWs displays the characteristics of normal rectifying diodes. The photocurrent under ultraviolet (UV) exposure was around 6 times higher than the dark current at the reverse bias of -5 V.

  15. Sensitivity analysis the influence of the average energy and FWHM of the initial fluence electrons in the determination of a spectrum of photons Bremsstrahlung of a linear accelerator; Analisis de sensibilidad de la influencia de la energia media y FWHM de la fluencia inicial de electrones en la determinacion de un espectro de fotones Bremsstrahlung de accelerador lineal

    Energy Technology Data Exchange (ETDEWEB)

    Justo, B.; Miro, R.; Verdu, G.; Diez, S.; Campayo, J. M.

    2011-07-01

    The main objective of this work is to study the effects of the initial beam characteristics of electrons in the absorbed dose distribution calculated by Monte Carlo for a photons beam of 6 MeV emitted by a medical linear accelerator.

  16. Conjugated-Polymer Blends for Organic Photovoltaics: Rational Control of Vertical Stratification for High Performance.

    Science.gov (United States)

    Yan, Yu; Liu, Xuan; Wang, Tao

    2017-05-01

    The photoactive layer of bulk-heterojunction organic solar cells, in a thickness range of tens to hundreds of nanometers, comprises phase-separated electron donors and acceptors after solution casting. The component distribution in the cross-section of these thin films is found to be heterogeneous, with electron donors or acceptors accumulated or depleted near the electrode interfaces. This vertical stratification of the photovoltaic blend influences device metrics through its impact on charge transport and recombination, and consequently plays an important role in determining the power conversion efficiency of photovoltaic devices. Here, different techniques, e.g., surface analysis and sputter-assisted depth-profiling, reflectivity modeling, and 3D imaging, that have been employed to characterize vertical stratification in bulk-heterojunction photovoltaic blends are reviewed. The origins of vertical stratification are summarized, including thermodynamics, kinetics, surface free energy, and selective dissolubility. The impact of correct and wrong vertical stratification to device metrics of solar cells are highlighted. Examples are then given to demonstrate how desired vertical stratification can be controlled with properly aligned device architecture to enable solar cells with high efficiency. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. A Physician's Perspective On Vertical Integration.

    Science.gov (United States)

    Berenson, Robert A

    2017-09-01

    Vertical integration has been a central feature of health care delivery system change for more than two decades. Recent studies have demonstrated that vertically integrated health care systems raise prices and costs without observable improvements in quality, despite many theoretical reasons why cost control and improved quality might occur. Less well studied is how physicians view their newfound partnerships with hospitals. In this article I review literature findings and other observations on five aspects of vertical integration that affect physicians in their professional and personal lives: patients' access to physicians, physician compensation, autonomy versus system support, medical professionalism and culture, and lifestyle. I conclude that the movement toward physicians' alignment with and employment in vertically integrated systems seems inexorable but that policy should not promote such integration either intentionally or inadvertently. Instead, policy should address the flaws in current payment approaches that reward high prices and excessive service use-outcomes that vertical integration currently produces. Project HOPE—The People-to-People Health Foundation, Inc.

  18. Vertical saccades in children: a developmental study.

    Science.gov (United States)

    Bucci, Maria Pia; Seassau, Magali

    2014-03-01

    There are no studies exploring the development of vertical saccades in large populations of children. In this study, we examined the development of vertical saccades in sixty-nine children. Binocular eye movements were recorded using an infrared video oculography system [Mobile EBT(®), e(ye)BRAIN], and movements from both eyes had been analyzed. The gain and the peak velocity of vertical saccades show an up-down asymmetry. Latency value decreases with the age of children, and it does not depend on the direction of the saccades; in contrast, the gain and the peak velocity values of vertical saccades are stable during childhood. We suggest that the up-down asymmetry is developed early, or is innate, in humans. Latencies of vertical saccades develop with the age of children, in relationship with the development of the cortical network responsible for the saccade preparation. In contrast, the precision and the peak velocity are not age-dependent as they are controlled by the cerebellum and brainstem structures.

  19. Ultra-thin flexible GaAs photovoltaics in vertical forms printed on metal surfaces without interlayer adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Juho; Song, Kwangsun; Kim, Namyun; Lee, Jongho, E-mail: jong@gist.ac.kr [School of Mechanical Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Hwang, Jeongwoo [Photonic Bio Research Center, Korea Photonics Technology Institute (KOPTI), 9 Cheomdanventure-ro 108beon-gil, Gwangju 61007 (Korea, Republic of); Shin, Jae Cheol [Department of Physics, Yeungnam University, Gyeongsan, Gyeongbuk 38541 (Korea, Republic of)

    2016-06-20

    Wearable flexible electronics often require sustainable power sources that are also mechanically flexible to survive the extreme bending that accompanies their general use. In general, thinner microelectronic devices are under less strain when bent. This paper describes strategies to realize ultra-thin GaAs photovoltaics through the interlayer adhesiveless transfer-printing of vertical-type devices onto metal surfaces. The vertical-type GaAs photovoltaic devices recycle reflected photons by means of bottom electrodes. Systematic studies with four different types of solar microcells indicate that the vertical-type solar microcells, at only a quarter of the thickness of similarly designed lateral-type cells, generate a level of electric power similar to that of thicker cells. The experimental results along with the theoretical analysis conducted here show that the ultra-thin vertical-type solar microcells are durable under extreme bending and thus suitable for use in the manufacturing of wearable flexible electronics.

  20. Electron-positron pair production by ultrarelativistic electrons in a soft photon field

    Science.gov (United States)

    Mastichiadis, A.; Marscher, A. P.; Brecher, K.

    1986-01-01

    The fully differential cross section for photon-electron pair production is integrated numerically over phase space. Results are obtained for the astrophysically interesting case in which the interaction between an ultrarelativistic electron and a soft photon results in electron-positron pair production. The positron spectrum is a function of the energies of both the photon and the electron, as well as the angle of interaction. It is found that the energy at which the positron distribution peaks is inversely proportional to the photon energy and independent of the electron energy. The positron spectrum is integrated once more over initial electron energies for a power-law energy distribution of primary electrons. The same procedure is repeated for the recoil particle; it is shown that the peak of the recoil energy distribution depends linearly on the energy of the primary electron. Finally, semianalytical expressions are obtained for the energy losses of the primary electrons.

  1. Hypernuclear spectroscopy with electron beam at JLab Hall C

    Energy Technology Data Exchange (ETDEWEB)

    Yuu Fujii

    2010-12-01

    Hypernuclear spectroscopy with electron beam at JLab Hall C has been studied since 2000. The first experiment, JLab E89-009, used Short Orbit Spectrometer (SOS) as a kaon arm and a split-pole type spectrometer (ENGE) as an electron arm. E89-009 employed zero-degree tagging method, which tags scattered electrons at zero-degree and the kaon arm also covered zero-degree. This method obtains maximum yield of hypernuclei but sufferers from high rate background of electrons from bremsstrahlung and positrons from pair-creation. Nevertheless, this experiment demonstrated the possibility of the (e,e' K{sup +}) reaction for hypernuclear spectroscopy by obtaining a hypernuclear mass spectrum with an energy resolution of better than 1 MeV (FWHM) [1][2]. However, poor signal to noise ratio and poor statistics requires us to improve the experimental setup. Therefore, E01-011 experiment was proposed based on the success of the JLab E01-011 experiment. Improvements of E01-011 from E09-009 can be summarized as: 1. Employed newly constructed high resolution kaon spectrometer (HKS) as a kaon arm. 2. Employed so-called 'tilt-method' for the electron arm. With the newly constructed HKS, having 2-10-4 momentum resolution, we expect an energy resolution of 400 keV (FWHM). The 'tilt-method' means the electron arm is tilted vertically to the splitter dispersive plane to avoid background electrons from bremsstrahlung and moeller scattering. The setup allowed us to use up to a few tens beam. The experiment was performed in 2005 and final result will be shown shortly. The third experiment, JLab E05-115 experiment was proposed as a natural extension of E01-011 experiment and will be performed in 2009. Improvements of experimental setup are, 1. Employed newly constructed high resolution electron spectrometer (HES) as a electron arm, 2. Employed a new charge-separation magnet (Splitter), fully customized for hypernuclear experiment at Hall C. With the third generation

  2. The marine diversity spectrum

    Science.gov (United States)

    Reuman, Daniel C; Gislason, Henrik; Barnes, Carolyn; Mélin, Frédéric; Jennings, Simon

    2014-01-01

    Distributions of species body sizes within a taxonomic group, for example, mammals, are widely studied and important because they help illuminate the evolutionary processes that produced these distributions. Distributions of the sizes of species within an assemblage delineated by geography instead of taxonomy (all the species in a region regardless of clade) are much less studied but are equally important and will illuminate a different set of ecological and evolutionary processes. We develop and test a mechanistic model of how diversity varies with body mass in marine ecosystems. The model predicts the form of the ‘diversity spectrum’, which quantifies the distribution of species' asymptotic body masses, is a species analogue of the classic size spectrum of individuals, and which we have found to be a new and widely applicable description of diversity patterns. The marine diversity spectrum is predicted to be approximately linear across an asymptotic mass range spanning seven orders of magnitude. Slope −0·5 is predicted for the global marine diversity spectrum for all combined pelagic zones of continental shelf seas, and slopes for large regions are predicted to lie between −0·5 and −0·1. Slopes of −0·5 and −0·1 represent markedly different communities: a slope of −0·5 depicts a 10-fold reduction in diversity for every 100-fold increase in asymptotic mass; a slope of −0·1 depicts a 1·6-fold reduction. Steeper slopes are predicted for larger or colder regions, meaning fewer large species per small species for such regions. Predictions were largely validated by a global empirical analysis. Results explain for the first time a new and widespread phenomenon of biodiversity. Results have implications for estimating numbers of species of small asymptotic mass, where taxonomic inventories are far from complete. Results show that the relationship between diversity and body mass can be explained from the dependence of predation behaviour

  3. Dissociated vertical deviation and eye torsion: Relation to disparity-induced vertical vergence

    NARCIS (Netherlands)

    L.J. van Rijn; H.J. Simonsz (Huib); M.P.M. ten Tusscher

    1997-01-01

    textabstractWe studied the relation between vertical eye movements and binocular torsion in five subjects with dissociated vertical deviation (DVD). During trials, subject viewed a well illuminated Snellen letter chart, with both eyes uncovered during 4 seconds. Subsequently, DVD was induced by

  4. Facilitation of vertical vergence by horizontal saccades, found in a patient with dissociated vertical deviation.

    NARCIS (Netherlands)

    H.J. Simonsz (Huib); L.J. van Dijk (Laurens)

    1994-01-01

    textabstractAbstract The authors examined vertical vergence in a Is-year-old girl with dissociated vertical deviation, a 60 convergent strabismus, no binocular vision, latent nystagmus, and a minimal left amblyopia. Eye movements were recorded during 4s-periods of (1) both eyes open, alternated with

  5. Lateral and Vertical Organic Transistors

    Science.gov (United States)

    Al-Shadeedi, Akram

    An extensive study has been performed to provide a better understanding of the operation principles of doped organic field-effect transistors (OFETs), organic p-i-n diodes, Schottky diodes, and organic permeable base transistors (OPBTs). This has been accomplished by a combination of electrical and structural characterization of these devices. The discussion of doped OFETs focuses on the shift of the threshold voltage due to increased doping concentrations and the generation and transport of minority charge carriers. Doping of pentacene OFETs is achieved by co-evaporation of pentacene with the n-dopant W2(hpp)4. It is found that pentacene thin film are efficiently doped and that a conductivity in the range of 2.6 x 10-6 S cm-1 for 1 wt% to 2.5 x 10-4 S cm-1 for 16 wt% is reached. It is shown that n-doped OFET consisting of an n-doped channel and n-doped contacts are ambipolar. This behavior is surprising, as n-doping the contacts should suppress direct injection of minority charge carriers (holes). It was proposed that minority charge carrier injection and hence the ambipolar characteristic of n-doped OFETs can be explained by Zener tunneling inside the intrinsic pentacene layer underneath the drain electrode. It is shown that the electric field in this layer is indeed in the range of the breakdown field of pentacene based p-i-n Zener homodiodes. Doping the channel has a profound influence on the onset voltage of minority (hole) conduction. The onset voltage can be shifted by lightly n-doping the channel. The shift of onset voltage can be explained by two mechanisms: first, due to a larger voltage that has to be applied to the gate in order to fully deplete the n-doped layer. Second, it can be attributed to an increase in hole trapping by inactive dopants. Moreover, it has been shown that the threshold voltage of majority (electron) conduction is shifted by an increase in the doping concentration, and that the ambipolar OFETs can be turned into unipolar OFETs at

  6. Plasmonic Properties of Vertically Aligned Nanowire Arrays

    Directory of Open Access Journals (Sweden)

    Hua Qi

    2012-01-01

    Full Text Available Nanowires (NWs/Ag sheath composites were produced to investigate plasmonic coupling between vertically aligned NWs for surface-enhanced Raman scattering (SERS applications. In this investigation, two types of vertical NW arrays were studied; those of ZnO NWs grown on nanosphere lithography patterned sapphire substrate via vapor-liquid-solid (VLS mechanism and Si NW arrays produced by wet chemical etching. Both types of vertical NW arrays were coated with a thin layer of silver by electroless silver plating for SERS enhancement studies. The experimental results show extremely strong SERS signals due to plasmonic coupling between the NWs, which was verified by COMSOL electric field simulations. We also compared the SERS enhancement intensity of aligned and random ZnO NWs, indicating that the aligned NWs show much stronger and repeatable SERS signal than those grown in nonaligned geometries.

  7. The Revolutionary Vertical Lift Technology (RVLT) Project

    Science.gov (United States)

    Yamauchi, Gloria K.

    2018-01-01

    The Revolutionary Vertical Lift Technology (RVLT) Project is one of six projects in the Advanced Air Vehicles Program (AAVP) of the NASA Aeronautics Research Mission Directorate. The overarching goal of the RVLT Project is to develop and validate tools, technologies, and concepts to overcome key barriers for vertical lift vehicles. The project vision is to enable the next generation of vertical lift vehicles with aggressive goals for efficiency, noise, and emissions, to expand current capabilities and develop new commercial markets. The RVLT Project invests in technologies that support conventional, non-conventional, and emerging vertical-lift aircraft in the very light to heavy vehicle classes. Research areas include acoustic, aeromechanics, drive systems, engines, icing, hybrid-electric systems, impact dynamics, experimental techniques, computational methods, and conceptual design. The project research is executed at NASA Ames, Glenn, and Langley Research Centers; the research extensively leverages partnerships with the US Army, the Federal Aviation Administration, industry, and academia. The primary facilities used by the project for testing of vertical-lift technologies include the 14- by 22-Ft Wind Tunnel, Icing Research Tunnel, National Full-Scale Aerodynamics Complex, 7- by 10-Ft Wind Tunnel, Rotor Test Cell, Landing and Impact Research facility, Compressor Test Facility, Drive System Test Facilities, Transonic Turbine Blade Cascade Facility, Vertical Motion Simulator, Mobile Acoustic Facility, Exterior Effects Synthesis and Simulation Lab, and the NASA Advanced Supercomputing Complex. To learn more about the RVLT Project, please stop by booth #1004 or visit their website at https://www.nasa.gov/aeroresearch/programs/aavp/rvlt.

  8. Stoppage in Autism Spectrum Disorders

    DEFF Research Database (Denmark)

    Grønborg, Therese Koops; Hansen, Stefan Nygaard; Nielsen, Svend V

    2015-01-01

    of bias in sibling recurrence risk estimation. This study investigated whether stoppage occurs in Danish families with a firstborn child diagnosed with autism spectrum disorders, and if stoppage was differential. We found that stoppage occurs moderately in Danish families affected by autism spectrum...... disorders, and that stoppage is differential. However, differential stoppage is a minor source of estimation bias in Danish sibling recurrence risk studies of autism spectrum disorders....

  9. Rotational spectrum of tryptophan

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, M. Eugenia, E-mail: maria.sanz@kcl.ac.uk; Cabezas, Carlos, E-mail: ccabezas@qf.uva.es; Mata, Santiago, E-mail: santiago.mata@uva.es; Alonso, Josè L., E-mail: jlalonso@qf.uva.es [Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Unidad Asociada CSIC, Parque Científico Uva, Universidad de Valladolid, 47011 Valladolid (Spain)

    2014-05-28

    The rotational spectrum of the natural amino acid tryptophan has been observed for the first time using a combination of laser ablation, molecular beams, and Fourier transform microwave spectroscopy. Independent analysis of the rotational spectra of individual conformers has conducted to a definitive identification of two different conformers of tryptophan, with one of the observed conformers never reported before. The analysis of the {sup 14}N nuclear quadrupole coupling constants is of particular significance since it allows discrimination between structures, thus providing structural information on the orientation of the amino group. Both observed conformers are stabilized by an O–H···N hydrogen bond in the side chain and a N–H···π interaction forming a chain that reinforce the strength of hydrogen bonds through cooperative effects.

  10. Electromagnetic spectrum management system

    Science.gov (United States)

    Seastrand, Douglas R.

    2017-01-31

    A system for transmitting a wireless countermeasure signal to disrupt third party communications is disclosed that include an antenna configured to receive wireless signals and transmit wireless counter measure signals such that the wireless countermeasure signals are responsive to the received wireless signals. A receiver processes the received wireless signals to create processed received signal data while a spectrum control module subtracts known source signal data from the processed received signal data to generate unknown source signal data. The unknown source signal data is based on unknown wireless signals, such as enemy signals. A transmitter is configured to process the unknown source signal data to create countermeasure signals and transmit a wireless countermeasure signal over the first antenna or a second antenna to thereby interfere with the unknown wireless signals.

  11. Autism Spectrum Disorders

    Directory of Open Access Journals (Sweden)

    Rebecca E. Rosenberg

    2011-01-01

    Full Text Available We used a national online registry to examine variation in cumulative prevalence of community diagnosis of psychiatric comorbidity in 4343 children with autism spectrum disorders (ASD. Adjusted multivariate logistic regression models compared influence of individual, family, and geographic factors on cumulative prevalence of parent-reported anxiety disorder, depression, bipolar disorder, and attention deficit/hyperactivity disorder or attention deficit disorder. Adjusted odds of community-assigned lifetime psychiatric comorbidity were significantly higher with each additional year of life, with increasing autism severity, and with Asperger syndrome and pervasive developmental disorder—not otherwise specified compared with autistic disorder. Overall, in this largest study of parent-reported community diagnoses of psychiatric comorbidity, gender, autistic regression, autism severity, and type of ASD all emerged as significant factors correlating with cumulative prevalence. These findings could suggest both underlying trends in actual comorbidity as well as variation in community interpretation and application of comorbid diagnoses in ASD.

  12. Electromagnetic spectrum management system

    Energy Technology Data Exchange (ETDEWEB)

    Seastrand, Douglas R.

    2017-10-17

    A system for transmitting a wireless countermeasure signal to disrupt third party communications is disclosed that include an antenna configured to receive wireless signals and transmit wireless counter measure signals such that the wireless countermeasure signals are responsive to the received wireless signals. A receiver processes the received wireless signals to create processed received signal data while a spectrum control module subtracts known source signal data from the processed received signal data to generate unknown source signal data. The unknown source signal data is based on unknown wireless signals, such as enemy signals. A transmitter is configured to process the unknown source signal data to create countermeasure signals and transmit a wireless countermeasure signal over the first antenna or a second antenna to thereby interfere with the unknown wireless signals.

  13. Theoretical Investigation of Subwavelength Gratings and Vertical Cavity Lasers Employing Grating Structures

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza

    directions, which is analogous to electronic quantum wells in conduction or valence bands. Several interesting configurations of heterostructures have been investigated and their potential in fundamental physics study and applications are discussed. For numerical and theoretical studies, a three...... laterally coupled cavities is proposed and investigated, which exhibits the breaking of parity-time (PT) symmetry in vertical cavity structures. Compared to other types of platform for studying this phenomenon such as ring/disk resonators and photonic crystal cavities, the HCG/HG-based vertical cavities...... appear to be more feasible for realizing an electrically pumped device, which may pave the way for finding device applications for PT-symmetry breaking phenomenon....

  14. Tangential and Vertical Compact Torus Injection Experiments on the STOR-M Tokamak

    Science.gov (United States)

    Xiao, Chijin; D, Liu; S, Livingstone; A, K. Singh; E, Zhang; A, Hirose

    2005-04-01

    This paper describes the setup and results of compact torus (CT) injection experiments on the STOR-M tokamak. Tangential CT injection into STOR-M induced H-mode-like phenomena including doubling the electron density, reduction in the Hα radiation level, suppression of the floating potential fluctuations, suppression of the m = 2 Mirnov oscillations, and increase in the global energy confinement time. Experimental setup, bench-test results, and some preliminary injection data for vertical CT injection experiments on STOR-M will be shown. In addition, numerical simulations of the CT trajectories in tokamak discharges for both tangential and vertical injection geometries will be discussed.

  15. Certified standards and vertical coordination in aquaculture

    DEFF Research Database (Denmark)

    Trifkovic, Neda

    2014-01-01

    the application of standards and contract farming, processing companies prefer to vertically integrate primary production largely due to concerns over the stable supply of pangasius with satisfactory quality and safety attributes. These tendencies increase the market dominance of industrial farming and worsen......This paper explores the interaction between food standards and vertical coordination in the Vietnamese pangasius sector. For farmers and processors alike, the adoption of standards is motivated by a desire to improve market access by ensuring high quality supply. Instead of encouraging...

  16. Thermal Stratification in Vertical Mantle Tanks

    DEFF Research Database (Denmark)

    Knudsen, Søren; Furbo, Simon

    2001-01-01

    are carried out to investigate how the thermal stratification is affected by different placements of the mantle inlet. The heat transfer between the solar collector fluid in the mantle and the domestic water in the inner tank is analysed by CFD-simulations. Furthermore, the flow pattern in the vertical mantle......It is well known that it is important to have a high degree of thermal stratification in the hot water storage tank to achieve a high thermal performance of SDHW systems. This study is concentrated on thermal stratification in vertical mantle tanks. Experiments based on typical operation conditions...

  17. CIRSS vertical data integration, San Bernardino study

    Science.gov (United States)

    Hodson, W.; Christenson, J.; Michel, R. (Principal Investigator)

    1982-01-01

    The creation and use of a vertically integrated data base, including LANDSAT data, for local planning purposes in a portion of San Bernardino County, California are described. The project illustrates that a vertically integrated approach can benefit local users, can be used to identify and rectify discrepancies in various data sources, and that the LANDSAT component can be effectively used to identify change, perform initial capability/suitability modeling, update existing data, and refine existing data in a geographic information system. Local analyses were developed which produced data of value to planners in the San Bernardino County Planning Department and the San Bernardino National Forest staff.

  18. Vertically Integrated Multinationals and Productivity Spillovers

    DEFF Research Database (Denmark)

    Clementi, Federico; Bergmann, Friedrich

    are not automatic. In this paper, we study how these externalities are affected by the strategy of vertical integration of foreign multinationals. Our analysis, based on firm-level data of European manufacturing companies, shows that local firms perceive weaker backward spillovers if client foreign affiliates...... are vertically integrated in their industry. The spillovers that arise from the activity of companies that do not invest in the domestic firms’ industry are 2.6 to 5 times stronger than the ones than come from affiliates of multinationals that invest in the industry of local firms....

  19. Geophysical aspects of vertical streamer seismic data

    Energy Technology Data Exchange (ETDEWEB)

    Sognnes, Walter

    1998-12-31

    Vertical cable acquisition is performed by deploying a certain number of vertical hydrophone arrays in the water column, and subsequently shooting a source point on top of it. The advantage of this particular geometry is that gives a data set with all azimuths included. Therefore a more complete 3-D velocity model can be derived. In this paper there are presented some results from the Fuji survey in the Gulf of Mexico. Based on these results, improved geometries and review recommendations for future surveys are discussed. 7 figs.

  20. Developing Handheld Video Intervention for Students with Autism Spectrum Disorder

    Science.gov (United States)

    Hughes, Elizabeth M.; Yakubova, Gulnoza

    2016-01-01

    Video-based intervention (VBI) has strong evidence supporting efficiency in teaching social, communication, functional, behavior, play, and self-help skills and emerging evidence for teaching academic skills to students with autism spectrum disorder (ASD). VBI allows opportunities to electronically provide personalized, consistent, and prerecorded…

  1. Decay energy of 55 Fe from its inner Bremsstrahlung spectrum

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... Several measurements of decay energy using the inner Bremsstrahlung spectrum (IB) due to radiative electron capture in 55Fe has been made. But the results are not uniform. Hence another attempt has been made at the same. Experimental data was obtained with a 4.445 cm. dia × 5.08 cm thick NaI (Tl) ...

  2. Statistics of vertical backscatter profiles of cirrus clouds

    Directory of Open Access Journals (Sweden)

    P. Veglio

    2011-12-01

    Full Text Available A nearly global statistical analysis of vertical backscatter and extinction profiles of cirrus clouds collected by the CALIOP lidar, on-board of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation, is presented.

    Statistics on frequency of occurrence and distribution of bulk properties of cirrus clouds in general and, for the first time, of horizontally homogeneous (on a 5-km field of view cirrus clouds only are provided. Annual and seasonal backscatter profiles (BSP are computed for the horizontally homogeneous cirri. Differences found in the day/night cases and for midlatitudes and tropics are studied in terms of the mean physical parameters of the clouds from which they are derived.

    The relationship between cloud physical parameters (optical depth, geometrical thickness and temperature and the shape of the BSP is investigated. It is found that cloud geometrical thickness is the main parameter affecting the shape of the mean CALIOP BSP. Specifically, cirrus clouds with small geometrical thicknesses show a maximum in mean BSP curve located near cloud top. As the cloud geometrical thickness increases the BSP maximum shifts towards cloud base. Cloud optical depth and temperature have smaller effects on the shape of the CALIOP BSPs. In general a slight increase in the BSP maximum is observed as cloud temperature and optical depth increase.

    In order to fit mean BSPs, as functions of geometrical thickness and position within the cloud layer, polynomial functions are provided. The impact on satellite radiative transfer simulations in the infrared spectrum when using either a constant ice-content (IWC along the cloud vertical dimension or an IWC profile derived from the BSP fitting functions is evaluated. It is, in fact, demonstrated that, under realistic hypotheses, the mean BSP is linearly proportional to the IWC profile.

  3. Reconstruction of Vertical Profile of Permittivity of Layered Media which is Probed Using Vertical Differential Antenna

    Science.gov (United States)

    Pochanin, Gennadiy P.; Poyedinchuk, Anatoliy Y.; Varianytsia-Roshchupkina, Liudmyla A.; Pochanina, Iryna Ye.

    2016-04-01

    Results of this research are intended to use at GPR investigations of layered media (for example, at roads' inspection) for the processing of collected data and reconstruction of dependence of permittivity on the depth. Recently, an antenna system with a vertical differential configuration of receiving module (Patent UA81652) for GPR was suggested and developed The main advantage of the differential antennas in comparison with bistatic antennas is a high electromagnetic decoupling between the transmitting and receiving modules. The new vertical differential configuration has an additional advantage because it allows collecting GPR data reflected by layered media without any losses of information about these layers [1] and, potentially, it is a more accurate instrument for the layers thickness measurements [2]. The developed antenna system is tested in practice with the GPR at asphalt thickness measurements [3] and shown an accuracy which is better than 0.5 cm. Since this antenna system is good for sounding from above the surface (air coupled technique), the mobile laboratory was equipped with the developed GPR [3]. In order to process big set of GPR data that collected during probing at long routes of the roads, for the data processing it was tested new algorithm of the inverse problem solution. It uses a fast algorithm for calculation of electromagnetic wave diffraction by non-uniform anisotropic layers [4]. The algorithm is based on constructing a special case solution to the Riccati equation for the Cauchy problem and enables a qualitative description of the wave diffraction by the electromagnetic structure of the type within a unitary framework. At this stage as initial data we used synthetic GPR data that were obtained as results of the FDTD simulation of the problem of UWB electromagnetic impulse diffraction on layered media. Differential and bistatic antenna configurations were tested at several different profiles of permittivity. Meanings of permittivity of

  4. 33 CFR 118.85 - Lights on vertical lift bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

  5. On the measurement of vertical velocity by MST radar

    Science.gov (United States)

    Gage, K. S.

    1983-01-01

    An overview is presented of the measurement of atmospheric vertical motion utilizing the MST radar technique. Vertical motion in the atmosphere is briefly discussed as a function of scale. Vertical velocity measurement by MST radars is then considered from within the context of the expected magnitudes to be observed. Examples are drawn from published vertical velocity observations.

  6. Control of polariton spectrum in bigyrotropic medium.

    Science.gov (United States)

    Dzedolik, Igor V; Karakchieva, Olga

    2013-09-01

    The ion and electron polarizations under the influence of high-frequency electromagnetic field and external magnetostatic field in a bigyrotropic medium (dielectric with magnetic subsystem) are considered. The polariton spectra in the bigyrotropic medium are received. It is shown that the polariton spectrum and the velocity of polariton wave can be controlled by the variation of the intensity and direction of external magnetostatic field. It becomes possible because the ion and electron Larmor's frequencies depend on the external magnetostatic field that leads to the appearance of several additional resonances of the permittivity and permeability of the medium. The wave vector and velocity of polariton wave that are close to the resonance frequencies vary depending on the wave frequency: the polariton wave velocity drops to zero before the resonance and increases after it. The wave velocity control may be used for designing controllable devices for a data-transmitting line.

  7. Temporal and spatial variations in ionospheric electron density profiles over South Africa during strong magnetic storms

    National Research Council Canada - National Science Library

    Yao, Y. B; Chen, P; Zhang, S; Chen, J. J

    2013-01-01

    ...) and vertical total electron content (VTEC) data from the Jason-1 satellite were used to analyze the variations in ionospheric electron density profiles over South Africa before and after the severe geomagnetic storms on 15 May 2005...

  8. WAVE-VORTEX MODE COUPLING IN ASTROPHYSICAL ACCRETION DISKS UNDER COMBINED RADIAL AND VERTICAL STRATIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    Salhi, A. [Departement de Physique, Faculte des Sciences de Tunis, 1060 Tunis (Tunisia); Lehner, T. [LUTH, UMR 8102 CNRS, Observatoire de Paris-Meudon, 5 place de Janssen, F-92195 Meudon (France); Godeferd, F.; Cambon, C. [Laboratoire de Mecanique des Fluides et d' Acoustique, Ecole Centrale de Lyon, Universite de Lyon, UMR 5509, CNRS, INSA, UCB, F-69134 Ecully Cedex (France)

    2013-07-10

    We examine accretion disk flow under combined radial and vertical stratification utilizing a local Cartesian (or ''shearing box'') approximation. We investigate both axisymmetric and nonaxisymmetric disturbances with the Boussinesq approximation. Under axisymmetric disturbances, a new dispersion relation is derived. It reduces to the Solberg-Hoieland criterion in the case without vertical stratification. It shows that, asymptotically, stable radial and vertical stratification cannot induce any linear instability; Keplerian flow is accordingly stable. Previous investigations strongly suggest that the so-called bypass concept of turbulence (i.e., that fine-tuned disturbances of any inviscid smooth shear flow can reach arbitrarily large transient growth) can also be applied to Keplerian disks. We present an analysis of this process for three-dimensional plane-wave disturbances comoving with the shear flow of a general rotating shear flow under combined stable radial and vertical rotation. We demonstrate that large transient growth occurs for K{sub 2}/k{sub 1} >> 1 and k{sub 3} = 0 or k{sub 1} {approx} k{sub 3}, where k{sub 1}, K{sub 2}, and k{sub 3} are the azimuthal, radial, and vertical components of the initial wave vector, respectively. By using a generalized ''wave-vortex'' decomposition of the disturbance, we show that the large transient energy growth in a Keplerian disk is mainly generated by the transient dynamics of the vortex mode. The analysis of the power spectrum of total (kinetic+potential) energy in the azimuthal or vertical directions shows that the contribution coming from the vortex mode is dominant at large scales, while the contribution coming from the wave mode is important at small scales. These findings may be confirmed by appropriate numerical simulations in the high Reynolds number regime.

  9. Electrostatic comb drive for vertical actuation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A. P., LLNL

    1997-07-10

    The electrostatic comb finger drive has become an integral design for microsensor and microactuator applications. This paper reports on utilizing the levitation effect of comb fingers to design vertical-to-the-substrate actuation for interferometric applications. For typical polysilicon comb drives with 2 {micro}m gaps between the stationary and moving fingers, as well as between the microstructures and the substrate, the equilibrium position is nominally 1-2 {micro}m above the stationary comb fingers. This distance is ideal for many phase shifting interferometric applications. Theoretical calculations of the vertical actuation characteristics are compared with the experimental results, and a general design guideline is derived from these results. The suspension flexure stiffnesses, gravity forces, squeeze film damping, and comb finger thicknesses are parameters investigated which affect the displacement curve of the vertical microactuator. By designing a parallel plate capacitor between the suspended mass and the substrate, in situ position sensing can be used to control the vertical movement, providing a total feedback-controlled system. Fundamentals of various capacitive position sensing techniques are discussed. Experimental verification is carried out by a Zygo distance measurement interferometer.

  10. Vertical distribution of natural radionuclides in soils

    Directory of Open Access Journals (Sweden)

    Lozano J. C.

    2012-04-01

    Full Text Available Low-level alpha spectrometry techniques using semiconductor detectors (PIPS and liquid scintillation counters (LKB Quantulus 1220™ were used in order to determine the activity concentration of 238U, 232Th, 234U, 230Th, 226Ra, and 210Pb in soil samples. The soils were collected from an old disused uranium mine located in southwest Spain. The soils were selected with different levels of influence from the installation, in such a way that they had different levels of radioactive contamination. The vertical profiles in the soils (down to 40 cm depth were studied in order to evaluate the vertical distribution of the natural radionuclides. The possible contamination of subsurface waters depends strongly on vertical migration, and the transfer to plants (herbs, shrubs, and trees also will depend on the distribution of the radionuclides in the root zone. The study of the activity ratios between radionuclides belonging to the same series allowed us to assess the differing behaviour of the radionuclides involved. The vertical profiles for these radionuclides were different at each sampling point, showing the local impact of the installation. However, the profiles per point were similar for the long-lived radionuclides of the 238TJ series (238U, 234U, 230Th, and 226Ra. Also, a major disequilibrium was observed between 210Pb and 226Ra in the surface layer, due to 222Rn emanation and subsequent surface deposition of 210Pb.

  11. Breakwaters with Vertical and Inclined Concrete Walls

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk

    Following the PIANC PTC II working group on Analyses of Rubble Mound Breakwaters it was, in 1991, decided to form Working Group (WG) n° 28 on "Breakwaters with vertical and inclined concrete walls" The scope of the work was to achieve a better understanding of the overall safety aspects...

  12. Flow and scour around vertical submerged structures

    Indian Academy of Sciences (India)

    Although past investigations establish the effect of various parameters on scour around vertical submerged structures for live and clear water condition, yet further studies are required to analyze the scour around group of submerged structures for various bed sediments, understand the flow physics around the group and ...

  13. integrated vertical photobioreactor system for carbon dioxide

    African Journals Online (AJOL)

    Astri Nugroho

    2013-07-02

    Jul 2, 2013 ... Abstract. A vertical photobioreactor containing the microalgae Scenedesmus obliquus is a highly efficient system for converting carbon dioxide (CO2) into biomass. The use of photobioreactor for CO2 mitigation has been explored using microalgae as photosynthetic microorganism. The growth rate (μ, h-1) ...

  14. DIURNAL VERTICAL MIGRATIONS OF MEIOFAUNA IN AN ...

    African Journals Online (AJOL)

    Diurnal vertical migrations of meiofauna were observed in an estuarine sand flat and these were related primarily to desiccation and temperature. The migrations. which occurred in the top 10 cm of the sediment. had a mean range of 5 cm and were most strongly exhibited by the interstitial flatworms. polychaetes and ...

  15. Determinants Of Vertical And Horizontal Export Diversification ...

    African Journals Online (AJOL)

    This implies that not all types of natural resource endowment have a 'Dutch disease' effect. While inflation, exchange rate, and foreign aid variables have a mixed effect on vertical and horizontal export diversification, political instability however has a strong adverse effect on export diversification; especially for SSA. The key ...

  16. Phase diagram of vertically vibrated dense suspensions

    NARCIS (Netherlands)

    von Kann, S.; Snoeijer, Jacobus Hendrikus; van der Meer, Roger M.

    2014-01-01

    When a hole is created in a layer of a dense, vertically vibrated suspension, phenomena are known to occur that defy the natural tendency of gravity to close the hole. Here, an overview is presented of the different patterns that we observed in a variety of dense particulate suspensions.

  17. OBSERVATIONS ON THE DIEL VERTICAL DISTRIBUTION OF ...

    African Journals Online (AJOL)

    Diel vertical migration (DVM) of six common species of hydromedusae was investigated during two drogue studies conducted in St Helena Bay on the west coast of South Africa in February 1995. Clytia spp., Obelia spp. and Bougainvillia macloviana, were largely confined to surface waters and did not appear to display any ...

  18. Vertical reflector for bifacial PV-panels

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Thorsteinsson, Sune; Poulsen, Peter Behrensdorff

    2016-01-01

    Bifacial solar modules offer an interesting price/performance ratio, and much work has been focused on directing the ground albedo to the back of the solar cells. In this work we design and develop a reflector for a vertical bifacial panel, with the objective to optimize the energy harvest...

  19. Optical anisotropy in vertically coupled quantum dots

    DEFF Research Database (Denmark)

    Yu, Ping; Langbein, Wolfgang Werner; Leosson, Kristjan

    1999-01-01

    We have studied the polarization of surface and edge-emitted photoluminescence (PL) from structures with vertically coupled In0.5Ga0.5As/GaAs quantum dots (QD's) grown by molecular beam epitaxy. The PL polarization is found to be strongly dependent on the number of stacked layers. While single...

  20. Manufacturing: the new case for vertical integration

    NARCIS (Netherlands)

    Kumpe, Ted; Bolwijn, Piet

    1988-01-01

    The article argues that the solid corporation will continue to view vertical integration as a critical part of manufacturing reform. Manufacturing reform and backward integration are related in insidious ways to the three stages of production over which the big manufacturers preside. Without

  1. Integrated Vertical Photobioreactor System for Carbon Dioxide ...

    African Journals Online (AJOL)

    A vertical photobioreactor containing the microalgae Scenedesmus obliquus is a highly efficient system for converting carbon dioxide (CO2) into biomass. The use of photobioreactor for CO2 mitigation has been explored using microalgae as photosynthetic microorganism. The growth rate (m, h-1) were 0.03; 0.13; 0.20; 0.09 ...

  2. The Design Philosophy for a Vertical Breakwater

    DEFF Research Database (Denmark)

    Vrijling, J. K.; Burcharth, H. F.; Voortman, H. G.

    2000-01-01

    A consistent risk-based design philosophy for vertical breakwaters is proposed. The design philosophy consists of a two-step approach. The first step is the definition of the main function of the breakwater, which leads to a definition of failure. The second step is the choice of the acceptable...

  3. Surround-gated vertical nanowire quantum dots

    NARCIS (Netherlands)

    Van Weert, M.H.M.; Den Heijer, M.; Van Kouwen, M.P.; Algra, R.E.; Bakkers, E.P.A.M.; Kouwenhoven, L.P.; Zwiller, V.

    2010-01-01

    We report voltage dependent photoluminescence experiments on single indium arsenide phosphide (InAsP) quantum dots embedded in vertical surround-gated indium phosphide (InP) nanowires. We show that by tuning the gate voltage, we can access different quantum dot charge states. We study the

  4. Vertical diffuse attenuation coefficient (Kd) based optical ...

    Indian Academy of Sciences (India)

    The optical classification of the different water types provides vital input for studies related to primary productivity, water clarity and determination of euphotic depth. Image data of the IRS- P3 MOS-B, for Path 90 of 27th February, 1998 was used for deriving vertical diffuse attenuation Coeffcient () and an optical ...

  5. Magnetohydrodynamic mixed convection flow in vertical concentric ...

    Indian Academy of Sciences (India)

    This work reports an analytical solution for fully developed mixed convection flow of viscous,incompressible, electrically conducting fluid in vertical concentric annuli under the influence of a transverse magnetic field, where the outer surface of inner cylinder is heated sinusoidally and the inner surface of outercylinder is kept ...

  6. A note on partial vertical integration

    NARCIS (Netherlands)

    G.W.J. Hendrikse (George); H.J.M. Peters (Hans)

    1989-01-01

    textabstractA simple model is constructed to show how partial vertical integration may emerge as an equilibrium market structure in a world characterized by rationing, differences in the reservation prices of buyers, and in the risk attitudes of buyers and sellers. The buyers with the high

  7. Vertical integration of HRD policy within companies

    NARCIS (Netherlands)

    Wognum, Ida

    2001-01-01

    This study concerns HRD policy making in companies. More specifically, it explores whether so-called vertical integration of HRD policy at different organizational levels occurs within companies. The study involved forty-four large companies in the industrial and the financial and commercial

  8. Vertical Integration Spurs American Health Care Revolution.

    Science.gov (United States)

    Phillips, Richard C.

    1986-01-01

    Under new "managed health care systems," the classical functional separation of risk taker, claims payor, and provider are vertically integrated into a common entity. This evolution should produce a competitive environment with medical care rendered to all Americans on a more cost-effective basis. (CJH)

  9. Vertical Integration: Teachers' Knowledge and Teachers' Voice.

    Science.gov (United States)

    Corrie, L.

    1995-01-01

    Traces the theoretical basis for vertical integration in early school years. Contrasts transmission-based pedagogy with a higher level of teacher control, and acquirer-based pedagogy with a higher level of student control. Suggests that early childhood pedagogy will be maintained when teachers are able to articulate their pedagogical knowledge and…

  10. Vertical diffuse attenuation coefficient (Kd) based optical ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    The optical classification of the different water types provides vital input for studies related to primary productivity, water clarity and determination of euphotic depth. Image data of the IRS-. P3 MOS-B, for Path 90 of 27th February, 1998 was used for deriving vertical diffuse attenuation coefficient (Kd) and an optical ...

  11. Vertical electrical resistivity investigation of foundation conditions ...

    African Journals Online (AJOL)

    Four Vertical Electrical Soundings have been carried out for building sites using Schlumberger array within a buried River channel near Okilton close, Port Harcourt. The objective was to delineate the different geoelectric and geologic parameters of the subsurface as a means of determining its effect on foundation.

  12. Vertical and horizontal transmission drive bacterial invasion

    NARCIS (Netherlands)

    Kremer, N.; Huigens, M.E.

    2011-01-01

    A huge variety of Arthropod species is infected with endosymbiotic Wolbachia bacteria that manipulate their host’s reproduction to invade populations. In addition to vertical transmission from mother to offspring through the egg cytoplasm, it has been demonstrated through phylogenetic analyses and

  13. Modeling vertical coral connectivity and mesophotic refugia

    Science.gov (United States)

    Holstein, Daniel M.; Paris, Claire B.; Vaz, Ana C.; Smith, Tyler B.

    2016-03-01

    Whether mesophotic reefs will behave as refugia for corals threatened by global climate change and coastal development depends on vertical exchange of larvae between diverse habitats. Here we use a biophysical model of larval dispersal to estimate vertical connectivity of a broadcasting ( Orbicella faveolata) and a brooding ( Porites astreoides) species of coral in the US Virgin Islands. Modeling predicts subsidy to shallow areas by mesophotic larvae of both species based on local hydrology, adult reproductive characteristics, larval traits, and a wide range of scenarios developed to test depth-sensitive factors, such as fertilization rates and post-settlement survivorship. In extreme model scenarios of reduced fertilization and post-settlement survivorship of mesophotic larvae, 1-10 % local mesophotic subsidy to shallow recruitment is predicted for both species, which are demographically significant. Although direct vertical connectivity is higher for the broadcaster, the brooder demonstrates higher local multigenerational vertical connectivity, which suggests that local P. astreoides populations are more resilient than those of O. faveolata, and corroborates field studies. As shallow habitat degrades, mesophotic-shallow subsidy is predicted to increase for both species. This study is the first of its kind to simulate larval dispersal and settlement between habitats of different depths, and these findings have local, regional, and global implications for predicting and managing coral reef persistence in a changing climate.

  14. Hinged-Blade, Vertical-Shaft Windmill

    Science.gov (United States)

    Shultz, B., Jr.

    1985-01-01

    Vertical-shaft windmill concept calls for hinged, flapping blades to increase energy-conversion efficiency by reducing wind-energy loss. Hinged Blade Halves unfold to catch wind when moving with it, then fold away from wind when moving against it.

  15. Aging effects on vertical graphene nanosheets and their thermal stability

    Science.gov (United States)

    Ghosh, S.; Polaki, S. R.; Ajikumar, P. K.; Krishna, N. G.; Kamruddin, M.

    2017-10-01

    The present study investigates environmental aging effects and thermal stability of vertical graphene nanosheets (VGN). Self-organized VGN is synthesized by plasma enhanced chemical vapor deposition and exposed to ambient conditions over 6-month period to examine its aging behavior. A systematic inspection is carried out on morphology, chemical structure, wettability and electrical property by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, water contact angle and four-probe resistivity measurements at regular intervals, respectively. Detailed microscopic and spectroscopic analysis substantiated the retention of graphitic quality and surface chemistry of VGN over the test period. An unchanged sheet resistance and hydrophobicity reveals its electrical and wetting stability over the time, respectively. Thermogravimetric analysis ensures an excellent thermal stability of VGN up to 575 °C in ambient atmosphere. These findings of long-term morphological, structural, wetting, electrical and thermal stability of VGN validate their potential utilization for the next-generation device applications.

  16. Graphene-based vertical-junction diodes and applications

    Science.gov (United States)

    Choi, Suk-Ho

    2017-09-01

    In the last decade, graphene has received extreme attention as an intriguing building block for electronic and photonic device applications. This paper provides an overview of recent progress in the study of vertical-junction diodes based on graphene and its hybrid systems by combination of graphene and other materials. The review is especially focused on tunnelling and Schottky diodes produced by chemical doping of graphene or combination of graphene with various semiconducting/ insulating materials such as hexagonal boron nitrides, Si-quantum-dots-embedded SiO2 multilayers, Si wafers, compound semiconductors, Si nanowires, and porous Si. The uniqueness of graphene enables the application of these convergence structures in high-efficient devices including photodetectors, solar cells, resonant tunnelling diodes, and molecular/DNA sensors.

  17. Stable Fe nanomagnets encapsulated inside vertically-aligned carbon nanotubes.

    Science.gov (United States)

    Bondino, Federica; Magnano, Elena; Ciancio, Regina; Castellarin Cudia, Carla; Barla, Alessandro; Carlino, Elvio; Yakhou-Harris, Flora; Rupesinghe, Nalin; Cepek, Cinzia

    2017-11-28

    Well-defined sized (5-10 nm) metallic iron nanoparticles (NPs) with body-centered cubic structure encapsulated inside the tip of millimeter-long vertically aligned carbon nanotubes (VACNTs) of uniform length have been investigated with high-resolution transmission electron microscopy and soft X-ray spectroscopy techniques. Surface-sensitive and chemically-selective measurements have been used to evaluate the magnetic properties of the encapsulated NPs. The encapsulated Fe NPs display magnetic remanence up to room temperature, low coercivity, high chemical stability and no significant anisotropy. Our surface-sensitive measurements combined with the specific morphology of the studied VACNTs allow us to pinpoint the contribution of the surface oxidized or hydroxidized iron catalysts present at the VACNT-substrate interface.

  18. Employing Beam-Gas Interaction Vertices for Transverse Profile Measurements

    CERN Document Server

    Rihl, Mariana; Baglin, Vincent; Barschel, Colin; Bay, Aurelio; Blanc, Frederic; Bravin, Enrico; Bregliozzi, Giuseppe; Chritin, Nicolas; Dehning, Bernd; Ferro-Luzzi, Massimiliano; Gaspar, Clara; Gianì, Sebastiana; Giovannozzi, Massimo; Greim, Roman; Haefeli, Guido; Hopchev, Plamen; Jacobsson, Richard; Jensen, Lars; Jones, Owain Rhodri; Jurado, Nicolas; Kain, Verena; Karpinski, Waclaw; Kirn, Thomas; Kuhn, Maria; Luthi, Berengere; Magagnin, Paolo; Matev, Rosen; Nakada, Tatsuya; Neufeld, Niko; Panman, Jaap; Rakotomiaramanana, Barinjaka; Salustino Guimaraes, Valdir; Salvant, Benoit; Schael, Stefan; Schneider, Olivier; Schwering, Georg; Tobin, Mark; Veness, Raymond; Veyrat, Quentin; Vlachos, Sotiris; Wlochal, Michael; Xu, Zhirui; von Dratzig, Arndt

    2016-01-01

    Interactions of high-energy beam particles with residual gas offer a unique opportunity to measure the beam profile in a non-intrusive fashion. Such a method was successfully pioneered* at the LHCb experiment using a silicon microstrip vertex detector. During the recent Large Hadron Collider shutdown at CERN, a demonstrator Beam-Gas Vertexing system based on eight scintillating-fibre modules was designed**, constructed and installed on Ring 2 to be operated as a pure beam diagnostics device. The detector signals are read out and collected with LHCb-type front-end electronics and a DAQ system consisting of a CPU farm. Tracks and vertices will be reconstructed to obtain a beam profile in real time. Here, first commissioning results are reported. The advantages and potential for future applications of this technique are discussed.

  19. An approach to electromagnetic spectrum evaluation and control for situational awareness

    CSIR Research Space (South Africa)

    Olivier, K

    2012-10-01

    Full Text Available In this presentation the author provides insight on the role of modern electronic warfare technology for the purposes of electromagnetic spectrum evaluation and control, which plays a crucial role in situational awareness required for peacekeeping...

  20. Electron-phonon interaction spectra in beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Najdyuk, Yu.G.; Shklyarevskij, O.I. (AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst. Nizkikh Temperatur)

    1982-09-01

    Micro-contact (MC) method was used to investigate spectra of electron-phonon interaction (EPI) in berillium. MC spectra and the known dependences of phonon state density in this metal have been compared in detail. It is shown that the MC spectra can be used for refining the berillium phonon spectrum. The EPI integral parameter has been determined in the free electron model.

  1. Quantum Entanglement Molecular Absorption Spectrum Simulator

    Science.gov (United States)

    Nguyen, Quang-Viet; Kojima, Jun

    2006-01-01

    Quantum Entanglement Molecular Absorption Spectrum Simulator (QE-MASS) is a computer program for simulating two photon molecular-absorption spectroscopy using quantum-entangled photons. More specifically, QE-MASS simulates the molecular absorption of two quantum-entangled photons generated by the spontaneous parametric down-conversion (SPDC) of a fixed-frequency photon from a laser. The two-photon absorption process is modeled via a combination of rovibrational and electronic single-photon transitions, using a wave-function formalism. A two-photon absorption cross section as a function of the entanglement delay time between the two photons is computed, then subjected to a fast Fourier transform to produce an energy spectrum. The program then detects peaks in the Fourier spectrum and displays the energy levels of very short-lived intermediate quantum states (or virtual states) of the molecule. Such virtual states were only previously accessible using ultra-fast (femtosecond) laser systems. However, with the use of a single-frequency continuous wave laser to produce SPDC photons, and QEMASS program, these short-lived molecular states can now be studied using much simpler laser systems. QE-MASS can also show the dependence of the Fourier spectrum on the tuning range of the entanglement time of any externally introduced optical-path delay time. QE-MASS can be extended to any molecule for which an appropriate spectroscopic database is available. It is a means of performing an a priori parametric analysis of entangled photon spectroscopy for development and implementation of emerging quantum-spectroscopic sensing techniques. QE-MASS is currently implemented using the Mathcad software package.

  2. Non-planar vertical photodetectors based on free standing two-dimensional SnS2 nanosheets.

    Science.gov (United States)

    Liu, Guangbo; Li, Zhonghua; Chen, Xiaoshuang; Zheng, Wei; Feng, Wei; Dai, Mingjin; Jia, Dechang; Zhou, Yu; Hu, PingAn

    2017-07-06

    The development trend of modern electronics and optoelectronics is towards continuous high integration and miniaturization. Using vertical configurations with three-dimensional geometry, it is easy to establish a higher integration density than the traditional planar one, and thus, this technology shows great promise for designing the next-generation electronics/optoelectronic devices. Two-dimensional (2D) layered metal dichalcogenides (2D-LMDs) are important building blocks for electronic/optoelectronic devices, where they are usually grown in parallel to the substrates during chemical vapor deposition (CVD), and consequently they are solely exploited to fabricate lateral structure devices with planar geometry. In this research, for the first time the vertical growth of free standing 2D layered nanosheets of hexagonal tin disulfide (SnS2) on a flat substrate was realized using a modified CVD method. Furthermore, it was successfully demonstrated, at the first attempt, that a type of non-planar vertical photodetector could be fabricated using free standing SnS2 nanosheets and this detector showed promise for photodetection applications. This work prepares the way for the growth of monodisperse vertical 2D-LMD nanosheets on flat substrates, and expands their use from conventional lateral structure devices to non-planar vertical electronic/optoelectronic devices.

  3. Dynamic Spectrum Sharing among Femtocells

    DEFF Research Database (Denmark)

    Da Costa, Gustavo Wagner Oliveira

    2012-01-01

    The ever-growing demand for mobile broadband is leading to an imminent spectrum scarcity. In order to cope with such situation dynamic spectrum sharing and the widespread deployment of small cells (femtocells) are promising solutions. Delivering such a view is not short of challenges. Massive...

  4. Autism Spectrum Disorder - Multiple Languages

    Science.gov (United States)

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Autism Spectrum Disorder URL of this page: https://medlineplus. ... V W XYZ List of All Topics All Autism Spectrum Disorder - Multiple Languages To use the sharing features on this page, ...

  5. Indecomposable polynomials and their spectrum

    Science.gov (United States)

    Bodin, Arnaud; Debes, Pierre; Najib, Salah

    We address some questions concerning indecomposable polynomials and their spectrum. How does the spectrum behave via reduction or specialization, or via a more general ring morphism? Are the indecomposability properties equivalent over a field and over its algebraic closure? How many polynomials are decomposable over a finite field?

  6. Excitation spectrum and high energy plasmons in single- and multi-layer graphene

    OpenAIRE

    Yuan, Shengjun; Roldán, Rafael; Katsnelson, Mikhail I.

    2011-01-01

    In this paper we study the excitation spectrum of single- and multi-layer graphene beyond the Dirac cone approximation. The dynamical polarizability of graphene is computed using a full $\\pi$-band tight-binding model, considering the possibility of inter-layer hopping in the calculation. The effect of electron-electron interaction is considered within the random phase approximation. We further discuss the effect of disorder in the spectrum, which leads to a smearing of the absorption peaks. O...

  7. Rotational Spectrum of Saccharine

    Science.gov (United States)

    Alonso, Elena R.; Mata, Santiago; Alonso, José L.

    2017-06-01

    A significant step forward in the structure-activity relationships of sweeteners was the assignment of the AH-B moiety in sweeteners by Shallenberger and Acree. They proposed that all sweeteners contain an AH-B moiety, known as glucophore, in which A and B are electronegative atoms separated by a distance between 2.5 to 4 Å. H is a hydrogen atom attached to one of the electronegative atom by a covalent bond. For saccharine, one of the oldest artificial sweeteners widely used in food and drinks, two possible B moieties exist ,the carbonyl oxygen atom and the sulfoxide oxygen atom although there is a consensus of opinion among scientists over the assignment of AH-B moieties to HN-SO. In the present work, the solid of saccharine (m.p. 220°C) has been vaporized by laser ablation (LA) and its rotational spectrum has been analyzed by broadband CP-FTMW and narrowband MB-FTMW Fourier transform microwave techniques. The detailed structural information extracted from the rotational constants and ^{14}N nuclear quadrupole coupling constants provided enough information to ascribe the glucophore's AH and B sites of saccharine. R. S. Shallenberger, T. E. Acree. Nature 216, 480-482 Nov 1967. R. S. Shallenberger. Taste Chemistry; Blackie Academic & Professional, London, (1993).

  8. Fetal Alcohol Spectrum Disorders.

    Science.gov (United States)

    Williams, Janet F; Smith, Vincent C

    2015-11-01

    Prenatal exposure to alcohol can damage the developing fetus and is the leading preventable cause of birth defects and intellectual and neurodevelopmental disabilities. In 1973, fetal alcohol syndrome was first described as a specific cluster of birth defects resulting from alcohol exposure in utero. Subsequently, research unequivocally revealed that prenatal alcohol exposure causes a broad range of adverse developmental effects. Fetal alcohol spectrum disorder (FASD) is the general term that encompasses the range of adverse effects associated with prenatal alcohol exposure. The diagnostic criteria for fetal alcohol syndrome are specific, and comprehensive efforts are ongoing to establish definitive criteria for diagnosing the other FASDs. A large and growing body of research has led to evidence-based FASD education of professionals and the public, broader prevention initiatives, and recommended treatment approaches based on the following premises:▪ Alcohol-related birth defects and developmental disabilities are completely preventable when pregnant women abstain from alcohol use.▪ Neurocognitive and behavioral problems resulting from prenatal alcohol exposure are lifelong.▪ Early recognition, diagnosis, and therapy for any condition along the FASD continuum can result in improved outcomes.▪ During pregnancy:◦no amount of alcohol intake should be considered safe;◦there is no safe trimester to drink alcohol;◦all forms of alcohol, such as beer, wine, and liquor, pose similar risk; and◦binge drinking poses dose-related risk to the developing fetus. Copyright © 2015 by the American Academy of Pediatrics.

  9. PINS Spectrum Identification Guide

    Energy Technology Data Exchange (ETDEWEB)

    A.J. Caffrey

    2012-03-01

    The Portable Isotopic Neutron Spectroscopy—PINS, for short—system identifies the chemicals inside munitions and containers without opening them, a decided safety advantage if the fill chemical is a hazardous substance like a chemical warfare agent or an explosive. The PINS Spectrum Identification Guide is intended as a reference for technical professionals responsible for the interpretation of PINS gamma-ray spectra. The guide is divided into two parts. The three chapters that constitute Part I cover the science and technology of PINS. Neutron activation analysis is the focus of Chapter 1. Chapter 2 explores PINS hardware, software, and related operational issues. Gamma-ray spectral analysis basics are introduced in Chapter 3. The six chapters of Part II cover the identification of PINS spectra in detail. Like the PINS decision tree logic, these chapters are organized by chemical element: phosphorus-based chemicals, chlorine-based chemicals, etc. These descriptions of hazardous, toxic, and/or explosive chemicals conclude with a chapter on the identification of the inert chemicals, e.g. sand, used to fill practice munitions.

  10. The Cu II Spectrum

    Directory of Open Access Journals (Sweden)

    Alexander Kramida

    2017-02-01

    Full Text Available New wavelength measurements in the vacuum ultraviolet (VUV, ultraviolet and visible spectral regions have been combined with available literature data to refine and extend the description of the spectrum of singly ionized copper (Cu II. In the VUV region, we measured 401 lines using a concave grating spectrograph and photographic plates. In the UV and visible regions, we measured 276 lines using a Fourier-transform spectrometer. These new measurements were combined with previously unpublished data from the thesis of Ross, with accurate VUV grating measurements of Kaufman and Ward, and with less accurate older measurements of Shenstone to construct a comprehensive list of ≈2440 observed lines, from which we derived a revised set of 379 optimized energy levels, complemented with 89 additional levels obtained using series formulas. Among the 379 experimental levels, 29 are new. Intensities of all lines observed in different experiments have been reduced to the same uniform scale by using newly calculated transition probabilities (A-values. We combined our calculations with published measured and calculated A-values to provide a set of 555 critically evaluated transition probabilities with estimated uncertainties, 162 of which are less than 20%.

  11. Comparison of RF spectrum prediction methods for dynamic spectrum access

    Science.gov (United States)

    Kovarskiy, Jacob A.; Martone, Anthony F.; Gallagher, Kyle A.; Sherbondy, Kelly D.; Narayanan, Ram M.

    2017-05-01

    Dynamic spectrum access (DSA) refers to the adaptive utilization of today's busy electromagnetic spectrum. Cognitive radio/radar technologies require DSA to intelligently transmit and receive information in changing environments. Predicting radio frequency (RF) activity reduces sensing time and energy consumption for identifying usable spectrum. Typical spectrum prediction methods involve modeling spectral statistics with Hidden Markov Models (HMM) or various neural network structures. HMMs describe the time-varying state probabilities of Markov processes as a dynamic Bayesian network. Neural Networks model biological brain neuron connections to perform a wide range of complex and often non-linear computations. This work compares HMM, Multilayer Perceptron (MLP), and Recurrent Neural Network (RNN) algorithms and their ability to perform RF channel state prediction. Monte Carlo simulations on both measured and simulated spectrum data evaluate the performance of these algorithms. Generalizing spectrum occupancy as an alternating renewal process allows Poisson random variables to generate simulated data while energy detection determines the occupancy state of measured RF spectrum data for testing. The results suggest that neural networks achieve better prediction accuracy and prove more adaptable to changing spectral statistics than HMMs given sufficient training data.

  12. On the Linearly-Balanced Kinetic Energy Spectrum

    Science.gov (United States)

    Lu, Huei,-Iin; Robertson, F. R.

    1999-01-01

    It is well known that the earth's atmospheric motion can generally be characterized by the two dimensional quasi-geostrophic approximation, in which the constraints on global integrals of kinetic energy, entrophy and potential vorticity play very important roles in redistributing the wave energy among different scales of motion. Assuming the hypothesis of Kolmogrov's local isotropy, derived a -3 power law of the equilibrium two-dimensional kinetic energy spectrum that entails constant vorticity and zero energy flows from the energy-containing wave number up to the viscous cutoff. In his three dimensional quasi-geostrophic theory, showed that the spectrum function of the vertical scale turbulence - expressible in terms of the available potential energy - possesses the same power law as the two dimensional kinetic energy spectrum. As the slope of kinetic energy spectrum in the inertial range is theoretically related to the predictability of the synoptic scales (Lorenz, 1969), many general circulation models includes a horizontal diffusion to provide reasonable kinetic energy spectra, although the actual power law exhibited in the atmospheric general circulation is controversial. Note that in either the atmospheric modeling or the observational analyses, the proper choice of wave number Index to represent the turbulence scale Is the degree of the Legendre polynomial.

  13. Distance spectrum of Indu–Bala product of graphs

    Directory of Open Access Journals (Sweden)

    G. Indulal

    2016-12-01

    Full Text Available The D-eigenvalues μ1,μ2,…,μn of a graph G of order n are the eigenvalues of its distance matrix D and form the distance spectrum or D-spectrum of G denoted by SpecD(G. Let G1 and G2 be two regular graphs. The Indu–Bala product of G1 and G2 is denoted by G1▾G2 and is obtained from two disjoint copies of the join G1∨G2 of G1 and G2 by joining the corresponding vertices in the two copies of G2. In this paper we obtain the distance spectrum of G1▾G2 in terms of the adjacency spectra of G1 and G2. We use this result to obtain a new class of distance equienergetic graphs of diameter 3. We also prove that the class of graphs Kn¯▾Kn+1¯ has integral distance spectrum.

  14. Using computerized tomography to determine ionospheric structures. Part 2, A method using curved paths to increase vertical resolution

    Energy Technology Data Exchange (ETDEWEB)

    Vittitoe, C.N.

    1993-08-01

    A method is presented to unfold the two-dimensional vertical structure in electron density by using data on the total electron content for a series of paths through the ionosphere. The method uses a set of orthonormal basis functions to represent the vertical structure and takes advantage of curved paths and the eikonical equation to reduce the number of iterations required for a solution. Curved paths allow a more thorough probing of the ionosphere with a given set of transmitter and receiver positions. The approach can be directly extended to more complex geometries.

  15. Transverse cervical skin incision and vertical platysma splitting approach for anterior cervical vertebral column exposure

    Directory of Open Access Journals (Sweden)

    Agrawal Amit

    2014-03-01

    Full Text Available Anterior surgical approaches provide direct access to symptomatic areas of the cervical spine, allow management of the vast spectrum of cervical spine pathologies and there are many articles in the literature that discussed these techniques in detail. Cosmesis is an important issue for patients who undergone surgeryon neck structures as an improperly placed incision attracting significant morbidity and few publications discuss this issue in details. The purpose of the present article is to describe our experience with transverse cervical skin incision and vertical platysma splitting approach for anterior cervical vertebral column exposure.

  16. Large aperture vertical cavity surface emitting laser with distributed-ring contact.

    Science.gov (United States)

    Hao, Yong-Qin; Luo, Yan; Feng, Yuan; Yan, Chang-Ling; Zhao, Ying-Jie; Wang, Yu-Xia; Wang, Xiao-Hua; Qu, Yi; Liu, Guo-Jun

    2011-03-01

    To overcome the serious current crowding effect in top-emitting vertical cavity surface emitting lasers (VCSELs) with large aperture, a distributed-ring-contact (DRC) VCSEL is proposed and demonstrated. A maximal cw light output power of more than 0.3 W and a wall-plug efficiency of 17.4% are achieved for a 300 μm-diameter VCSEL. The DRC VCSEL exhibits a more homogeneous emission profile, and the laser emits at 803.3 nm with a narrow spectrum (less than 0.2 nm FWHM). © 2011 Optical Society of America

  17. Multimode Jahn-Teller and pseudo-Jahn-Teller coupling effects in the photoelectron spectrum of CH 3F

    Science.gov (United States)

    Mahapatra, S.; Vallet, V.; Woywod, C.; Köppel, H.; Domcke, W.

    2004-09-01

    The multimode Jahn-Teller (JT) and pseudo-Jahn-Teller (PJT) coupling effects in the photoelectron spectrum of methylfluoride are theoretically investigated with the aid of an ab initio quantum dynamical approach. The theoretical findings are compared with the experimental results of Karlsson et al. [Phys. Scripta 16 (1977) 225]. At the vertical configuration, the ground, first and second excited electronic states of the methylfluoride radical cation belong to the 2E, 2A 1 and 2E symmetry species. The three doubly degenerate vibrational modes cause a splitting of the degeneracy of the E electronic states of the radical cation and exhibit the (E⊗e)-JT effect. The same vibrational modes may also cause a coupling of the degenerate and the non-degenerate electronic states (PJT effect). In our theoretical approach we devise a model diabatic vibronic Hamiltonian within a quadratic vibronic coupling scheme. The parameters of the Hamiltonian are derived by performing extensive ab initio calculations at the CASSCF-MR-AQCC level of theory. The photoelectron bands are calculated by a quantum dynamical approach based on the Lanczos algorithm. A detailed examination of the various static and dynamic aspects of the problem reveals an interesting interplay of JT and PJT coupling effects in the photoelectron-induced dynamics of CH 3F +. The resolved progression in the first photoelectron band corresponding to the ground X˜2E electronic manifold of CH 3F + is found to be mainly caused by the C-F stretching (a 1), C-F bending (e) and CH 3 deformation (e) modes. The JT coupling effects are not particularly strong in this electronic manifold. This also holds for the second photoelectron band attributed to the vibronic structure of the Ã2A1 and B˜2E electronic states of CH 3F +. However, the extremely large Condon activity of the symmetric vibrational modes in the Ã2A1 electronic state contributes much to the broad and highly diffuse nature of this band which is also observed

  18. Microfluidic stretchable RF electronics.

    Science.gov (United States)

    Cheng, Shi; Wu, Zhigang

    2010-12-07

    Stretchable electronics is a revolutionary technology that will potentially create a world of radically different electronic devices and systems that open up an entirely new spectrum of possibilities. This article proposes a microfluidic based solution for stretchable radio frequency (RF) electronics, using hybrid integration of active circuits assembled on flex foils and liquid alloy passive structures embedded in elastic substrates, e.g. polydimethylsiloxane (PDMS). This concept was employed to implement a 900 MHz stretchable RF radiation sensor, consisting of a large area elastic antenna and a cluster of conventional rigid components for RF power detection. The integrated radiation sensor except the power supply was fully embedded in a thin elastomeric substrate. Good electrical performance of the standalone stretchable antenna as well as the RF power detection sub-module was verified by experiments. The sensor successfully detected the RF radiation over 5 m distance in the system demonstration. Experiments on two-dimensional (2D) stretching up to 15%, folding and twisting of the demonstrated sensor were also carried out. Despite the integrated device was severely deformed, no failure in RF radiation sensing was observed in the tests. This technique illuminates a promising route of realizing stretchable and foldable large area integrated RF electronics that are of great interest to a variety of applications like wearable computing, health monitoring, medical diagnostics, and curvilinear electronics.

  19. Electronic Spectroscopy & Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Mark Maroncelli, Nancy Ryan Gray

    2010-06-08

    The Gordon Research Conference (GRC) on Electronic Spectroscopy and Dynamics was held at Colby College, Waterville, NH from 07/19/2009 thru 07/24/2009. The Conference was well-attended with participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. The GRC on Electronic Spectroscopy & Dynamics showcases some of the most recent experimental and theoretical developments in electronic spectroscopy that probes the structure and dynamics of isolated molecules, molecules embedded in clusters and condensed phases, and bulk materials. Electronic spectroscopy is an important tool in many fields of research, and this GRC brings together experts having diverse backgrounds in physics, chemistry, biophysics, and materials science, making the meeting an excellent opportunity for the interdisciplinary exchange of ideas and techniques. Topics covered in this GRC include high-resolution spectroscopy, biological molecules in the gas phase, electronic structure theory for excited states, multi-chromophore and single-molecule spectroscopies, and excited state dynamics in chemical and biological systems.

  20. The Vertical Farm: A Review of Developments and Implications for the Vertical City

    Directory of Open Access Journals (Sweden)

    Kheir Al-Kodmany

    2018-02-01

    Full Text Available This paper discusses the emerging need for vertical farms by examining issues related to food security, urban population growth, farmland shortages, “food miles”, and associated greenhouse gas (GHG emissions. Urban planners and agricultural leaders have argued that cities will need to produce food internally to respond to demand by increasing population and to avoid paralyzing congestion, harmful pollution, and unaffordable food prices. The paper examines urban agriculture as a solution to these problems by merging food production and consumption in one place, with the vertical farm being suitable for urban areas where available land is limited and expensive. Luckily, recent advances in greenhouse technologies such as hydroponics, aeroponics, and aquaponics have provided a promising future to the vertical farm concept. These high-tech systems represent a paradigm shift in farming and food production and offer suitable and efficient methods for city farming by minimizing maintenance and maximizing yield. Upon reviewing these technologies and examining project prototypes, we find that these efforts may plant the seeds for the realization of the vertical farm. The paper, however, closes by speculating about the consequences, advantages, and disadvantages of the vertical farm’s implementation. Economic feasibility, codes, regulations, and a lack of expertise remain major obstacles in the path to implementing the vertical farm.

  1. Adaptation of the vertical vestibulo-ocular reflex in cats during low-frequency vertical rotation.

    Science.gov (United States)

    Fushiki, Hiroaki; Maruyama, Motoyoshi; Shojaku, Hideo

    2017-04-27

    We examined plastic changes in the vestibulo-ocular reflex (VOR) during low-frequency vertical head rotation, a condition under which otolith inputs from the vestibular system are essential for VOR generation. For adaptive conditioning of the vertical VOR, 0.02Hz sinusoidal pitch rotation for one hour about the earth's horizontal axis was synchronized with out-of-phase vertical visual stimulation from a random dot pattern. A vertical VOR was well evoked when the upright animal rotated around the earth-horizontal axis (EHA) at low frequency due to the changing gravity stimulus and dynamic stimulation of the otoliths. After adaptive conditioning, the amplitude of the vertical VOR increased by an average of 32.1%. Our observations showing plasticity in the otolithic contribution to the VOR may provide a new strategy for visual-vestibular mismatch training in patients with otolithic disorders. This low-frequency vertical head rotation protocol also provides a model for investigating the mechanisms underlying the adaptation of VORs mediated by otolith activation. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Magnetic field alignment of randomly oriented, high aspect ratio silicon microwires into vertically oriented arrays.

    Science.gov (United States)

    Beardslee, Joseph A; Sadtler, Bryce; Lewis, Nathan S

    2012-11-27

    External magnetic fields have been used to vertically align ensembles of silicon microwires coated with ferromagnetic nickel films. X-ray diffraction and image analysis techniques were used to quantify the degree of vertical orientation of the microwires. The degree of vertical alignment and the minimum field strength required for alignment were evaluated as a function of the wire length, coating thickness, magnetic history, and substrate surface properties. Nearly 100% of 100 μm long, 2 μm diameter, Si microwires that had been coated with 300 nm of Ni could be vertically aligned by a 300 G magnetic field. For wires ranging from 40 to 60 μm in length, as the length of the wire increased, a higher degree of alignment was observed at lower field strengths, consistent with an increase in the available magnetic torque. Microwires that had been exposed to a magnetic sweep up to 300 G remained magnetized and, therefore, aligned more readily during subsequent magnetic field alignment sweeps. Alignment of the Ni-coated Si microwires occurred at lower field strengths on hydrophilic Si substrates than on hydrophobic Si substrates. The magnetic field alignment approach provides a pathway for the directed assembly of solution-grown semiconductor wires into vertical arrays, with potential applications in solar cells as well as in other electronic devices that utilize nano- and microscale components as active elements.

  3. Mobility Engineering in Vertical Field Effect Transistors Based on Van der Waals Heterostructures.

    Science.gov (United States)

    Shin, Yong Seon; Lee, Kiyoung; Kim, Young Rae; Lee, Hyangsook; Lee, I Min; Kang, Won Tae; Lee, Boo Heung; Kim, Kunnyun; Heo, Jinseong; Park, Seongjun; Lee, Young Hee; Yu, Woo Jong

    2018-01-15

    Vertical integration of 2D layered materials to form van der Waals heterostructures (vdWHs) offers new functional electronic and optoelectronic devices. However, the mobility in vertical carrier transport in vdWHs of vertical field-effect transistor (VFET) is not yet investigated in spite of the importance of mobility for the successful application of VFETs in integrated circuits. Here, the mobility in VFET of vdWHs under different drain biases, gate biases, and metal work functions is first investigated and engineered. The traps in WSe 2 are the main source of scattering, which influences the vertical mobility and three distinct transport mechanisms: Ohmic transport, trap-limited transport, and space-charge-limited transport. The vertical mobility in VFET can be improved by suppressing the trap states by raising the Fermi level of WSe 2 . This is achieved by increasing the injected carrier density by applying a high drain voltage, or decreasing the Schottky barrier at the graphene/WSe 2 and metal/WSe 2 junctions by applying a gate bias and reducing the metal work function, respectively. Consequently, the mobility in Mn vdWH at +50 V gate voltage is about 76 times higher than the initial mobility of Au vdWH. This work enables further improvements in the VFET for successful application in integrated circuits. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Bottom-up synthesis of vertically oriented two-dimensional materials

    Science.gov (United States)

    Vilá, R. A.; Momeni, K.; Wang, Q.; Bersch, B. M.; Lu, N.; Kim, M. J.; Chen, L. Q.; Robinson, J. A.

    2016-12-01

    Understanding nucleation and growth of two-dimensional (2D) and layered materials is a challenging topic due to the complex van der Waals interactions between layers and substrate. The morphology of 2D materials is known vary depending on experimental conditions. For the case of MoS2, the morphology has been shown to vary from rounded (molybdenum rich) domains to equilateral triangular (sulfur rich) domains. These different morphologies can result in drastically different properties, which can be exploited for applications in catalytic reactions, digital electronics, optoelectronics, and energy storage. Powder vaporization (PV) synthesis of molybdenum disulfide (MoS2) can yield vertical domains, however, these domains are often ignored when the morphology evolution of MoS2 is discussed, thereby completely omitting a major part of the impact of the Mo:S ratio to the growth mode of MoS2 during PV. Combining experimental and numerical simulation methods, we reveal a vertical-to-horizontal growth mode transition for MoS2 that occurs in the presence of a molybdenum oxide partial pressure gradient. Transmission electron microscopy reveals that the growth of vertical MoS2 results from initial seeding of single crystalline molybdenum dioxide, followed by sulfurization from the substrate upward to form vertically oriented MoS2 domains.

  5. Enhancement of absorption in vertically-oriented graphene sheets growing on a thin copper layer

    Energy Technology Data Exchange (ETDEWEB)

    Rozouvan, Tamara; Poperenko, Leonid [Taras Shevchenko National University of Kyiv, Department of Physics 4, Prospect Glushkova, Kyiv, 03187 (Ukraine); Kravets, Vasyl, E-mail: vasyl_kravets@yahoo.com [School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL (United Kingdom); Shaykevich, Igor [Taras Shevchenko National University of Kyiv, Department of Physics 4, Prospect Glushkova, Kyiv, 03187 (Ukraine)

    2017-02-28

    Highlights: • The optical properties and surface structure of graphene films. • Chemical vapour deposition method. • Scanning tunneling microscopy revealed vertical crystal lattice structure of graphene layer. • We report a significant enhancement of the absorption band in the vertically-oriented graphene sheets. - Abstract: The optical properties and surface structure of graphene films grown on thin copper Cu (1 μm) layer using chemical vapour deposition method were investigated via spectroscopic ellipsometry and nanoscopic measurements. Angle variable ellipsometry measurements were performed to analyze the features of dispersion of the complex refractive index and optical conductivity. It was observed significant enhancement of the absorption band in the vertically-oriented graphene sheets layer with respect to the bulk graphite due to interaction between excited localized surface plasmon at surface of thin Cu layer and graphene’s electrons. Scanning tunneling microscopy measurements with atomic spatial resolution revealed vertical crystal lattice structure of the deposited graphene layer. The obtained results provide direct evidence of the strong influence of the growing condition and morphology of nanostructure on electronic and optical behaviours of graphene film.

  6. Tsunami-driven gravity waves in the presence of vertically varying background and tidal wind structures

    Science.gov (United States)

    Laughman, B.; Fritts, D. C.; Lund, T. S.

    2017-05-01

    Many characteristics of tsunami-driven gravity waves (TDGWs) enable them to easily propagate into the thermosphere and ionosphere with appreciable amplitudes capable of producing detectable perturbations in electron densities and total electron content. The impact of vertically varying background and tidal wind structures on TDGW propagation is investigated with a series of idealized background wind profiles to assess the relative importance of wave reflection, critical-level approach, and dissipation. These numerical simulations employ a 2-D nonlinear anelastic finite-volume neutral atmosphere model which accounts for effects accompanying vertical gravity wave (GW) propagation such as amplitude growth with altitude. The GWs are excited by an idealized tsunami forcing with a 50 cm sea surface displacement, a 400 km horizontal wavelength, and a phase speed of 200 ms-1 consistent with previous studies of the tsunami generated by the 26 December 2004 Sumatra earthquake. Results indicate that rather than partial reflection and trapping, the dominant process governing TDGW propagation to thermospheric altitudes is refraction to larger and smaller vertical scales, resulting in respectively larger and smaller vertical group velocities and respectively reduced and increased viscous dissipation. Under all considered background wind profiles, TDGWs were able to attain ionospheric altitudes with appreciable amplitudes. Finally, evidence of nonlinear effects is observed and the conditions leading to their formation is discussed.

  7. Electron Microscopy.

    Science.gov (United States)

    Beer, Michael

    1980-01-01

    Reviews technical aspects of structure determination in biological electron microscopy (EM). Discusses low dose EM, low temperature microscopy, electron energy loss spectra, determination of mass or molecular weight, and EM of labeled systems. Cites 34 references. (CS)

  8. Mass spectrum bound state systems with relativistic corrections

    Energy Technology Data Exchange (ETDEWEB)

    Dineykhan, M; Zhaugasheva, S A [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Toinbaeva, N Sh; Jakhanshir, A [al-Farabi Kazak National University, 480012 Almaty (Kazakhstan)

    2009-07-28

    Based on the investigation of the asymptotic behaviour of the polarization loop function for charged n scalar particles in an external gauge field, we determine the interaction Hamiltonian including relativistic corrections. The mass spectrum of the bound state is analytically derived. The mechanism for arising of the constituent mass of the relativistic bound-state forming particles is explained. The mass and the constituent mass of the two-, three- and n-body relativistic bound states are calculated taking into account relativistic corrections. The corrections arising due to the one- and two-loop electron polarization to the energy spectrum of muonic hydrogen with orbital and radial excitations are calculated.

  9. Vertically Integrated Multiple Nanowire Field Effect Transistor.

    Science.gov (United States)

    Lee, Byung-Hyun; Kang, Min-Ho; Ahn, Dae-Chul; Park, Jun-Young; Bang, Tewook; Jeon, Seung-Bae; Hur, Jae; Lee, Dongil; Choi, Yang-Kyu

    2015-12-09

    A vertically integrated multiple channel-based field-effect transistor (FET) with the highest number of nanowires reported ever is demonstrated on a bulk silicon substrate without use of wet etching. The driving current is increased by 5-fold due to the inherent vertically stacked five-level nanowires, thus showing good feasibility of three-dimensional integration-based high performance transistor. The developed fabrication process, which is simple and reproducible, is used to create multiple stiction-free and uniformly sized nanowires with the aid of the one-route all-dry etching process (ORADEP). Furthermore, the proposed FET is revamped to create nonvolatile memory with the adoption of a charge trapping layer for enhanced practicality. Thus, this research suggests an ultimate design for the end-of-the-roadmap devices to overcome the limits of scaling.

  10. Vertical external cavity surface emitting semiconductor lasers

    CERN Document Server

    Holm, M

    2001-01-01

    Active stabilisation showed a relative locked linewidth of approx 3 kHz. Coarse tuning over 7 nm was achieved using a 3-plate birefingent filter plate while fine-tuning using cavity length change allowed tuning over 250 MHz. Vertical external cavity semiconductor lasers have emerged as an interesting technology based on current vertical cavity semiconductor laser knowledge. High power output into a single transverse mode has attracted companies requiring good fibre coupling for telecommunications systems. The structure comprises of a grown semiconductor Bragg reflector topped with a multiple quantum well gain region. This is then included in an external cavity. This device is then optically pumped to promote laser action. Theoretical modelling of AIGaAs based VECSEL structures was undertaken, showing the effect of device design on laser characteristics. A simple 3-mirror cavity was constructed to assess the static characteristics of the structure. Up to 153 mW of output power was achieved in a single transver...

  11. Ultimately short ballistic vertical graphene Josephson junctions.

    Science.gov (United States)

    Lee, Gil-Ho; Kim, Sol; Jhi, Seung-Hoon; Lee, Hu-Jong

    2015-01-30

    Much efforts have been made for the realization of hybrid Josephson junctions incorporating various materials for the fundamental studies of exotic physical phenomena as well as the applications to superconducting quantum devices. Nonetheless, the efforts have been hindered by the diffusive nature of the conducting channels and interfaces. To overcome the obstacles, we vertically sandwiched a cleaved graphene monoatomic layer as the normal-conducting spacer between superconducting electrodes. The atomically thin single-crystalline graphene layer serves as an ultimately short conducting channel, with highly transparent interfaces with superconductors. In particular, we show the strong Josephson coupling reaching the theoretical limit, the convex-shaped temperature dependence of the Josephson critical current and the exceptionally skewed phase dependence of the Josephson current; all demonstrate the bona fide short and ballistic Josephson nature. This vertical stacking scheme for extremely thin transparent spacers would open a new pathway for exploring the exotic coherence phenomena occurring on an atomic scale.

  12. New Urban Vertical Axis Wind Turbine Design

    Directory of Open Access Journals (Sweden)

    Alexandru-Mihai CISMILIANU

    2015-12-01

    Full Text Available This paper develops a different approach for enhancing the performance of Vertical Axis Wind Turbines for the use in the urban or rural environment and remote isolated residential areas. Recently the vertical axis wind turbines (VAWT have become more attractive due to the major advantages of this type of turbines in comparison to the horizontal axis wind turbines. We aim to enhance the overall performance of the VAWT by adding a second set of blades (3 x 2=6 blades following the rules of biplane airplanes. The model has been made to operate at a maximum power in the range of the TSR between 2 to 2.5. The performances of the VAWT were investigated numerically and experimentally and justify the new proposed design.

  13. Visible spectrum of stable sonoluminescence

    Science.gov (United States)

    Carlson, Joseph T.

    1992-12-01

    Synchronous emissions of picosecond pulses of light are observed to originate from a bubble trapped at the pressure antinode of a resonant sound field. The spectrum has been measured using a single slit spectrometer equipped with a linear array CCD detector. Spectra from differing solutions of water and glycerin are compared to the visible blackbody spectrum distribution. Assuming a blackbody model, apparent temperatures of 18,900 Kelvins are observed in pure water. Increasing glycerin concentration appears to correlate with cooler blackbody temperatures. The spectrum is also found to continually change with time, independent of input parameters.

  14. Electronic Commerce

    OpenAIRE

    Slavko Đerić

    2016-01-01

    Electronic commerce can be defined in different ways. Any definition helps to understand and explain that concept as better as possible.. Electronic commerce is a set of procedures and technologies that automate the tasks of financial transactions using electronic means. Also, according to some authors, electronic commerce is defined as a new concept, which is being developed and which includes process of buying and selling or exchanging products, services or information via computer networks...

  15. Understand electronics

    CERN Document Server

    Bishop, Owen

    2013-01-01

    Understand Electronics provides a readable introduction to the exciting world of electronics for the student or enthusiast with little previous knowledge. The subject is treated with the minimum of mathematics and the book is extensively illustrated.This is an essential guide for the newcomer to electronics, and replaces the author's best-selling Beginner's Guide to Electronics.The step-by-step approach makes this book ideal for introductory courses such as the Intermediate GNVQ.

  16. Vacuum electronics

    CERN Document Server

    Eichmeier, Joseph A

    2008-01-01

    Nineteen experts from the electronics industry, research institutes and universities have joined forces to prepare this book. ""Vacuum Electronics"" covers the electrophysical fundamentals, the present state of the art and applications, as well as the future prospects of microwave tubes and systems, optoelectronics vacuum devices, electron and ion beam devices, light and X-ray emitters, particle accelerators and vacuum interrupters. These topics are supplemented by useful information about the materials and technologies of vacuum electronics and vacuum technology.

  17. Electronic components

    CERN Document Server

    Colwell, Morris A

    1976-01-01

    Electronic Components provides a basic grounding in the practical aspects of using and selecting electronics components. The book describes the basic requirements needed to start practical work on electronic equipment, resistors and potentiometers, capacitance, and inductors and transformers. The text discusses semiconductor devices such as diodes, thyristors and triacs, transistors and heat sinks, logic and linear integrated circuits (I.C.s) and electromechanical devices. Common abbreviations applied to components are provided. Constructors and electronics engineers will find the book useful

  18. Electron Cloud: an Analytic View

    CERN Document Server

    Vos, L

    1998-01-01

    Electron cloud activity has been observed in some positron storage rings but not in others. It is a major concern for the LHC. In this paper the electron cloud problematics is treated purely analytica lly. The equilibrium electron cloud density is derived from the standard photon production rate, taking into account the photo-electric yield and the process of secondary emission. A fundamental ingre dient in the derivation is the Kollath{2] energy spectrum of the secondary emission. The phenomenon of space charge is discussed as well. The transverse acceleration of the electrons by the bunches is used to introduce the concept of closely and sparsely bunched beams. There is a fundamental difference between them, especially from the point of view of power deposition. Expressions for an equivalen t transverse impedance and imaginary tune shift are derived. Finally the analysis is confronted with electron cloud observations in existing positron machines (DAPHINE, PF, BEPC) before it is applied to the LHC. It comes...

  19. Vertical Silicon Nanowires for Image Sensor Applications

    OpenAIRE

    Park, Hyunsung

    2014-01-01

    Conventional image sensors achieve color imaging using absorptive organic dye filters. These face considerable challenges however in the trend toward ever higher pixel densities and advanced imaging methods such as multispectral imaging and polarization-resolved imaging. In this dissertation, we investigate the optical properties of vertical silicon nanowires with the goal of image sensor applications. First, we demonstrate a multispectral imaging system that uses a novel filter that consists...

  20. Centro-lateral subperiosteal vertical midface lift

    Directory of Open Access Journals (Sweden)

    Hönig, Johannes Franz

    2014-03-01

    Full Text Available The use of fiberendoscopic video-assisted technique in facial rejuvenation is one of the most advances in aesthetic plastic surgery of the face. It substitutes the coronal incision without the necessity of skin resection and allows a vertical reposition of the mobile soft tissue of the midface in indicated cases. It can easily be done through a small incision of the scalp just behind the coronal incision and in the temporal area.

  1. Electrically floating, near vertical incidence, skywave antenna

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.

    2014-07-08

    An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.

  2. Vertical leadership in a case company

    OpenAIRE

    Nguyen, Ngan

    2015-01-01

    The thesis concentrated about vertical leadership. The topic clarifies leadership behaviours in different styles. Based on unique characteristics would build up different leadership styles. A good leader is not only be independence, responsibility, visionary, but also must be interpersonal. Creating network through the rest of organization, a leader establishes relationship with his or her employees. Building trust then would help an organization overcome obstacles in order to accomplish comm...

  3. Predicting Vertical Motion within Convective Storms

    Science.gov (United States)

    van den Heever, S. C.

    2016-12-01

    Convective storms are both beneficial in the fresh water they supply and destructive in the life-threatening extreme weather they produce. They are found throughout the tropics and midlatitudes, vary in structure from isolated to highly organized systems, and are the sole source of precipitation in many regions of Earth. Convective updrafts and downdrafts plays a crucial role in cloud and precipitation formation, latent heating, water vapor transport, storm organization, and large-scale atmospheric circulations such as the Hadley and Walker cells. These processes, in turn, impact the strength and longevity of updrafts and downdrafts through complex, non-linear feedbacks. In spite of the significant influence of convective updrafts and downdrafts on the weather and climate system, accurately predicting vertical motion using numerical models remains challenging. In high-resolution cloud-resolving models where vertical motion is normally resolved, significant biases exist in the predicted profiles of updraft and downdraft velocities, at least for the limited cases where observational data have been available for model evaluation. It has been suggested that feedbacks between the vertical motion and microphysical processes may be one cause of these discrepancies, however, our understanding of these feedbacks remains limited. In this talk, the results of a small field campaign conducted over northeastern Colorado designed to observe storm vertical motion and cold pool characteristics within isolated and organized deep convective storms will be described. High frequency radiosonde, radar and drone measurements of a developing through mature supercell storm updraft and cold pool will be presented and compared with RAMS simulations of the same supercell storm. An analysis of the feedbacks between the storm dynamical and microphysical processes will be presented, and implications for regional and global modeling of severe storms will be discussed.

  4. Understanding Vertical Jump Potentiation: A Deterministic Model.

    Science.gov (United States)

    Suchomel, Timothy J; Lamont, Hugh S; Moir, Gavin L

    2016-06-01

    This review article discusses previous postactivation potentiation (PAP) literature and provides a deterministic model for vertical jump (i.e., squat jump, countermovement jump, and drop/depth jump) potentiation. There are a number of factors that must be considered when designing an effective strength-power potentiation complex (SPPC) focused on vertical jump potentiation. Sport scientists and practitioners must consider the characteristics of the subject being tested and the design of the SPPC itself. Subject characteristics that must be considered when designing an SPPC focused on vertical jump potentiation include the individual's relative strength, sex, muscle characteristics, neuromuscular characteristics, current fatigue state, and training background. Aspects of the SPPC that must be considered for vertical jump potentiation include the potentiating exercise, level and rate of muscle activation, volume load completed, the ballistic or non-ballistic nature of the potentiating exercise, and the rest interval(s) used following the potentiating exercise. Sport scientists and practitioners should design and seek SPPCs that are practical in nature regarding the equipment needed and the rest interval required for a potentiated performance. If practitioners would like to incorporate PAP as a training tool, they must take the athlete training time restrictions into account as a number of previous SPPCs have been shown to require long rest periods before potentiation can be realized. Thus, practitioners should seek SPPCs that may be effectively implemented in training and that do not require excessive rest intervals that may take away from valuable training time. Practitioners may decrease the necessary time needed to realize potentiation by improving their subject's relative strength.

  5. Vertical Carbon Nanotube Device in Nanoporous Templates

    Science.gov (United States)

    Maschmann, Matthew Ralph (Inventor); Fisher, Timothy Scott (Inventor); Sands, Timothy (Inventor); Bashir, Rashid (Inventor)

    2014-01-01

    A modified porous anodic alumina template (PAA) containing a thin CNT catalyst layer directly embedded into the pore walls. CNT synthesis using the template selectively catalyzes SWNTs and DWNTs from the embedded catalyst layer to the top PAA surface, creating a vertical CNT channel within the pores. Subsequent processing allows for easy contact metallization and adaptable functionalization of the CNTs and template for a myriad of applications.

  6. Multispectral imaging with vertical silicon nanowires

    OpenAIRE

    Park, Hyunsung; Crozier, Kenneth B.

    2013-01-01

    Multispectral imaging is a powerful tool that extends the capabilities of the human eye. However, multispectral imaging systems generally are expensive and bulky, and multiple exposures are needed. Here, we report the demonstration of a compact multispectral imaging system that uses vertical silicon nanowires to realize a filter array. Multiple filter functions covering visible to near-infrared (NIR) wavelengths are simultaneously defined in a single lithography step using a single material (...

  7. ELECTRONIC SIGNATURES

    African Journals Online (AJOL)

    10332324

    'electronic signature' means data attached to, incorporated in, or logically associated with other data and which is intended by the user to serve as a signature;. The suggested new definition for an electronic signature reads as follows: 'electronic signature' means a sound, symbol or process that is (i) uniquely linked to the ...

  8. ELECTRONIC SIGNATURES

    African Journals Online (AJOL)

    10332324

    (a) facilitate ecommerce;2. (b) remove and prevent barriers to electronic communications in South Africa;3. (c) ensure that electronic transactions in the Republic conform to the highest international standards;4. (d) promote the development of electronic transactions services which are responsive to the needs of users and ...

  9. Vertical and horizontal seismometric observations of tides

    Science.gov (United States)

    Lambotte, S.; Rivera, L.; Hinderer, J.

    2006-01-01

    Tidal signals have been largely studied with gravimeters, strainmeters and tiltmeters, but can also be retrieved from digital records of the output of long-period seismometers, such as STS-1, particularly if they are properly isolated. Horizontal components are often noisier than the vertical ones, due to sensitivity to tilt at long periods. Hence, horizontal components are often disturbed by local effects such as topography, geology and cavity effects, which imply a strain-tilt coupling. We use series of data (duration larger than 1 month) from several permanent broadband seismological stations to examine these disturbances. We search a minimal set of observable signals (tilts, horizontal and vertical displacements, strains, gravity) necessary to reconstruct the seismological record. Such analysis gives a set of coefficients (per component for each studied station), which are stable over years and then can be used systematically to correct data from these disturbances without needing heavy numerical computation. A special attention is devoted to ocean loading for stations close to oceans (e.g. Matsushiro station in Japon (MAJO)), and to pressure correction when barometric data are available. Interesting observations are made for vertical seismometric components; in particular, we found a pressure admittance between pressure and data 10 times larger than for gravimeters for periods larger than 1 day, while this admittance reaches the usual value of -3.5 nm/s 2/mbar for periods below 3 h. This observation may be due to instrumental noise, but the exact mechanism is not yet understood.

  10. Vertically integrated flow in stratified aquifers

    Science.gov (United States)

    Strack, Otto D. L.

    2017-05-01

    We present a set of continuous discharge potentials that can be used to determine the vertically integrated flow in stratified aquifers. The method applies to cases where the boundaries are vertical and either the hydraulic head is given, or the boundary is a seepage face, or the integrated discharge is given. The approach is valid for cases of given recharge through the upper and/or lower boundaries of the aquifer. The method is valid for any values of hydraulic conductivity; there are no limitations of the contrast for the method to be valid. The flows in the strata may be either confined or unconfined, and locally perched conditions may exist, but the effect of capillarity is not included. The hydraulic head is determined by applying the Dupuit-Forchheimer approximation. The main advantage of the approach is that very complex conditions in stratified aquifer systems, including locally perched conditions and extremely complex flow systems can be treated in a relatively straight forward approach by considering only the vertically integrated flow rates. The approach is particularly useful for assessing groundwater sustainability, as a model to be constructed prior to developing a fully three-dimensional numerical model.

  11. Dynamic stiffness of suction caissons - vertical vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, Lars Bo; Liingaard, M.; Andersen, Lars

    2006-12-15

    The dynamic response of offshore wind turbines are affected by the properties of the foundation and the subsoil. The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three-dimensional coupled Boundary Element/Finite Element model. Comparisons are made with known analytical and numerical solutions in order to evaluate the static and dynamic behaviour of the Boundary Element/Finite Element model. The vertical frequency dependent stiffness has been determined for different combinations of the skirt length, Poisson's ratio and the ratio between soil stiffness and skirt stiffness. Finally the dynamic behaviour at high frequencies is investigated. (au)

  12. A single-electron approach for many-electron dynamics in high-order harmonic generation

    CERN Document Server

    Schild, Axel

    2016-01-01

    We present a novel ab-initio single-electron approach to correlated electron dynamics in strong laser fields. By writing the electronic wavefunction as a product of a marginal one-electron wavefunction and a conditional wavefunction, we show that the exact harmonic spectrum can be obtained from a single-electron Schr\\"odinger equation. To obtain the one-electron potential in practice, we propose an adiabatic approximation, i.e. a potential is generated that depends only on the position of one electron. This potential, together with the laser interaction, is then used to obtain the dynamics of the system. For a model Helium atom in a laser field, we show that by using our approach, the high-order harmonic generation spectrum can be obtained to a good approximation.

  13. Conversion electron surface imaging

    CERN Document Server

    Irwin, G M; Wehner, A

    1999-01-01

    A method of imaging the Moessbauer absorption over the surface of a sample based on counting conversion electrons emitted from the surface following resonant absorption of gamma radiation is described. This Conversion Electron Surface Imaging (CESI) method is somewhat analogous to Magnetic Resonance Imaging (MRI), particularly chemical shift imaging, and similar tomographic reconstruction techniques are involved in extracting the image. The theory behind the technique and a prototype device is described, as well as the results of proof-of-principle experiments which demonstrate the function of the device. Eventually this same prototype device will be part of a system to determine the spatial variation of the Moessbauer spectrum over the surface of a sample. Applications include imaging of variations of surface properties of steels and other iron containing alloys, as well as other surfaces over which sup 5 sup 7 Fe has been deposited.

  14. PAMELA and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Mocchiutti, E., E-mail: Emiliano.Mocchiutti@ts.infn.i [INFN, Sezione di Trieste, Padriciano 99, I-34012 Trieste (Italy); Adriani, O. [University of Florence, Department of Physics, Via Sansone 1, I-50019 Sesto Fiorentino, Florence (Italy); INFN, Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Florence (Italy); Barbarino, G.C. [University of Naples ' Federico II' , Department of Physics, Via Cintia, I-80126 Naples (Italy); INFN, Sezione di Napoli, Via Cintia, I-80126 Naples (Italy); Bazilevskaya, G.A. [Lebedev Physical Institute, Leninsky Prospekt 53, RU-119991 Moscow (Russian Federation); Bellotti, R. [University of Bari, Department of Physics, Via Amendola 173, I-70126 Bari (Italy); INFN, Sezione di Bari, Via Amendola 173, I-70126 Bari (Italy); Boezio, M. [INFN, Sezione di Trieste, Padriciano 99, I-34012 Trieste (Italy); Bogomolov, E.A. [Ioffe Physical Technical Institute, Polytekhnicheskaya 26, RU-194021 St. Petersburg (Russian Federation); Bonechi, L.; Bongi, M. [University of Florence, Department of Physics, Via Sansone 1, I-50019 Sesto Fiorentino, Florence (Italy); INFN, Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Florence (Italy); Bonvicini, V. [INFN, Sezione di Trieste, Padriciano 99, I-34012 Trieste (Italy); Borisov, S. [INFN, Sezione di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, I-00133 Rome (Italy); Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, RU-11540 Moscow (Russian Federation); Bottai, S. [INFN, Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Florence (Italy); Bruno, A. [University of Bari, Department of Physics, Via Amendola 173, I-70126 Bari (Italy); INFN, Sezione di Bari, Via Amendola 173, I-70126 Bari (Italy); Cafagna, F. [INFN, Sezione di Bari, Via Amendola 173, I-70126 Bari (Italy); Campana, D. [INFN, Sezione di Napoli, Via Cintia, I-80126 Naples (Italy)

    2011-02-21

    The 15th of June 2006, the PAMELA satellite-borne experiment was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail counter scintillator and a neutron detector. The combination of these devices allows precision studies of the charged cosmic radiation to be conducted over a wide energy range (100 MeV-100's GeV) with high statistics. The measurement of the positron to electron fraction and of the electron energy spectrum in order to search for exotic sources, such as dark matter particle annihilations, are within the PAMELA primary scientific goal.

  15. Autism Spectrum Disorder and Fragile X Syndrome

    Science.gov (United States)

    ... only after another family member has been diagnosed. Autism Spectrum Disorder and Fragile X Syndrome Fragile X ... known single gene cause of ASD What Is Autism Spectrum Disorder? Autism spectrum disorder (ASD) is a ...

  16. Structure and optical anisotropy of vertically correlated submonolayer InAs/GaAs quantum dots

    DEFF Research Database (Denmark)

    Xu, Zhangcheng; Birkedal, Dan; Hvam, Jørn Märcher

    2003-01-01

    A vertically correlated submonolayer (VCSML) InAs/GaAs quantum-dot (QD) heterostructure was studied using transmission electron microscopy, high-resolution x-ray diffraction (HRXRD) and polarization-dependent photoluminescence. The HRXRD (004) rocking curve was simulated using the Tagaki-Taupin e......A vertically correlated submonolayer (VCSML) InAs/GaAs quantum-dot (QD) heterostructure was studied using transmission electron microscopy, high-resolution x-ray diffraction (HRXRD) and polarization-dependent photoluminescence. The HRXRD (004) rocking curve was simulated using the Tagaki...... with respect to GaAs is around 1.4%, while the lattice mismatch in the QW is negligible. The photoluminescence is transverse magnetic-polarized in the edge geometry....

  17. Macroscopic Synthesis of Vertically Aligned Carbon Nanotubes Using Floating Catalyst Chemical Vapor Deposition Method

    Science.gov (United States)

    Mirbagheri, S. Ahmad; Kazemzadeh, Asghar; Abedin Maghanaki, Amir

    2012-01-01

    In this paper, we report an efficient process to grow well-aligned carbon nanotube (CNT) arrays with a good area distribution density (about 5.6 ×107 CNT/mm2). Vertically aligned carbon nanotubes (VA-CNTs) have been produced by controlling flow rate, temperature and catalyst nanoparticles using a floating catalyst chemical vapor deposition (FC-CVD) technique. They were synthesized on quartz substrates at 800 °C from toluene as a carbon source. VA-CNT samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and their surface area and pore size were determined by nitrogen adsorption analysis. The synthesized CNTs have a length of 500 µm and diameters ranging from 120±40 nm. The CNT filaments form a strength structure and exhibit a good vertical alignment. The remarkable properties of CNTs make them attractive for separation applications, especially for water and wastewater treatment.

  18. Multidimensional Neuroanatomical Subtyping of Autism Spectrum Disorder.

    Science.gov (United States)

    Hong, Seok-Jun; Valk, Sofie L; Di Martino, Adriana; Milham, Michael P; Bernhardt, Boris C

    2017-09-14

    Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders with multiple biological etiologies and highly variable symptoms. Using a novel analytical framework that integrates cortex-wide MRI markers of vertical (i.e., thickness, tissue contrast) and horizontal (i.e., surface area, geodesic distance) cortical organization, we could show that a large multi-centric cohort of individuals with ASD falls into 3 distinctive anatomical subtypes (ASD-I: cortical thickening, increased surface area, tissue blurring; ASD-II: cortical thinning, decreased distance; ASD-III: increased distance). Bootstrap analysis indicated a high consistency of these biotypes across thousands of simulations, while analysis of behavioral phenotypes and resting-state fMRI showed differential symptom load (i.e., Autism Diagnostic Observation Schedule; ADOS) and instrinsic connectivity anomalies in communication and social-cognition networks. Notably, subtyping improved supervised learning approaches predicting ADOS score in single subjects, with significantly increased performance compared to a subtype-blind approach. The existence of different subtypes may reconcile previous results so far not converging on a consistent pattern of anatomical anomalies in autism, and possibly relate the presence of diverging corticogenic and maturational anomalies. The high accuracy for symptom severity prediction indicates benefits of MRI biotyping for personalized diagnostics and may guide the development of targeted therapeutic strategies. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  19. Abrasion of 6 dentifrices measured by vertical scanning interference microscopy

    Science.gov (United States)

    PASCARETTI-GRIZON, Florence; MABILLEAU, Guillaume; CHAPPARD, Daniel

    2013-01-01

    Objectives The abrasion of dentifrices is well recognized to eliminate the dental plaque. The aims of this study were to characterize the abrasive powders of 6 dentifrices (3 toothpastes and 3 toothpowders) and to measure the abrasion on a test surface by Vertical Scanning Interference microscopy (VSI). Material and Methods Bright field and polarization microscopy were used to identify the abrasive particles on the crude dentifrices and after prolonged washes. Scanning electron microscopy and microanalysis characterized the shape and nature of the particles. Standardized and polished blocks of poly(methylmethacrylate) were brushed with a commercial electric toothbrush with the dentifrices. VSI quantified the mean roughness (Ra) and illustrated in 3D the abraded areas. Results Toothpastes induced a limited abrasion. Toothpowders induced a significantly higher roughness linked to the size of the abrasive particles. One powder (Gencix® produced a high abrasion when used with a standard testing weight. However, the powder is based on pumice particles covered by a plant homogenate that readily dissolves in water. When used in the same volume, or after dispersion in water, Ra was markedly reduced. Conclusion Light and electron microscopy characterize the abrasive particles and VSI is a new tool allowing the analysis of large surface of abraded materials. PMID:24212995

  20. Wetting and surface energy of vertically aligned silicon nanowires.

    Science.gov (United States)

    Jana, S; Mondal, S; Bhattacharyya, S R

    2013-06-01

    The vertically aligned silicon nanowires (SiNWs) have been synthesized by metal assisted chemical etching process on commercially available p type silicon wafer. The aspect ratios of the SiNWs have been modified by simply varying the etching time. The microstructures of the as prepared samples have been investigated with the field emission scanning electron microscope as well as with a high resolution transmission electron microscope. The bonding information has been obtained by Fourier transformed infrared spectroscopy and X-ray photoelectron spectroscopy. The contact angles for water with the as-prepared SiNWs films were measured and found to be highly dependent upon the aspect ratio of the as synthesized wires. For obtaining a deep insight regarding the reasons behind this dependence the surface energies of the as prepared SiNWs films have been calculated by Owens method using two liquids, water and glycerol. The porosity of the films has been calculated indirectly from the equilibrium equations. It has been found that the etching time has a profound effect on the aspect ratio and thus on the surface energy of SiNWs that governs the wetting behaviour of the as prepared samples.

  1. Abrasion of 6 dentifrices measured by vertical scanning interference microscopy.

    Science.gov (United States)

    Pascaretti-Grizon, Florence; Mabilleau, Guillaume; Chappard, Daniel

    2013-01-01

    The abrasion of dentifrices is well recognized to eliminate the dental plaque. The aims of this study were to characterize the abrasive powders of 6 dentifrices (3 toothpastes and 3 toothpowders) and to measure the abrasion on a test surface by Vertical Scanning Interference microscopy (VSI). Bright field and polarization microscopy were used to identify the abrasive particles on the crude dentifrices and after prolonged washes. Scanning electron microscopy and microanalysis characterized the shape and nature of the particles. Standardized and polished blocks of poly(methylmethacrylate) were brushed with a commercial electric toothbrush with the dentifrices. VSI quantified the mean roughness (Ra) and illustrated in 3D the abraded areas. Toothpastes induced a limited abrasion. Toothpowders induced a significantly higher roughness linked to the size of the abrasive particles. One powder (Gencix® produced a high abrasion when used with a standard testing weight. However, the powder is based on pumice particles covered by a plant homogenate that readily dissolves in water. When used in the same volume, or after dispersion in water, Ra was markedly reduced. Light and electron microscopy characterize the abrasive particles and VSI is a new tool allowing the analysis of large surface of abraded materials.

  2. Transient reflectivity on vertically aligned single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Galimberti, Gianluca; Ponzoni, Stefano; Ferrini, Gabriele [Interdisciplinary Laboratory for Advanced Materials Physics (i-LAMP) and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, I-25121 Brescia (Italy); Hofmann, Stephan [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Arshad, Muhammad [Zernike Institute for Advanced Materials, University of Groningen (Netherlands); ICTP, Strada Costiera 11, I-34151 Trieste (Italy); National Centre for Physics Quaid-i-Azam University Islamabad (Pakistan); Cepek, Cinzia [Istituto Officina dei Materiali — CNR, Laboratorio TASC, Area Science Park, Basovizza, I-34149 Trieste (Italy); Pagliara, Stefania, E-mail: pagliara@dmf.unicatt.it [Interdisciplinary Laboratory for Advanced Materials Physics (i-LAMP) and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, I-25121 Brescia (Italy)

    2013-09-30

    One-color transient reflectivity measurements are carried out on two different samples of vertically aligned single-wall carbon nanotube bundles and compared with the response recently published on unaligned bundles. The negative sign of the optical response for both samples indicates that the free electron character revealed on unaligned bundles is only due to the intertube interactions favored by the tube bending. Neither the presence of bundles nor the existence of structural defects in aligned bundles is able to induce a free-electron like behavior of the photoexcited carriers. This result is also confirmed by the presence of non-linear excitonic effects in the transient response of the aligned bundles. - Highlights: • Transient reflectivity measurements on two aligned carbon nanotube samples • Relationship between unalignment and/or bundling and intertube interaction • The bundling is not able to modify the intertube interactions • The presence of structural defects does not affect the intertube interactions • A localized exciton-like behavior has been revealed in these samples.

  3. Family Process - Autism Spectrum Disorders

    OpenAIRE

    Benson, Mark

    2012-01-01

    Slides for a talk about family process and the importance of parenting dimensions in adolescent development. The slides list findings to date, and propose research into the influence of family on outcomes for those diagnosed with an autism spectrum disorder.

  4. Sticker electronics

    KAUST Repository

    Hussain, Muhammad Mustafa

    2017-09-08

    Electronic stickers may be manufactured on flexible substrates (110, 120, 130) as layers and packaged together. The package may then have an adhesive applied to one side to provide capability for sticking the electronic devices to surfaces. The stickers can be wrappable, placed on surfaces, glued on walls or mirrors or wood or stone, and have electronics (112, 122, 132) which may or may not be ultrathin. Packaging for the electronic sticker can use polymer on cellulose manufacturing and/or three dimensional (3-D) printing. The electronic stickers may provide lighting capability, sensing capability, and/or recharging capabilities.

  5. Basic electronics

    CERN Document Server

    Holbrook, Harold D

    1971-01-01

    Basic Electronics is an elementary text designed for basic instruction in electricity and electronics. It gives emphasis on electronic emission and the vacuum tube and shows transistor circuits in parallel with electron tube circuits. This book also demonstrates how the transistor merely replaces the tube, with proper change of circuit constants as required. Many problems are presented at the end of each chapter. This book is comprised of 17 chapters and opens with an overview of electron theory, followed by a discussion on resistance, inductance, and capacitance, along with their effects on t

  6. Electronic Government and Electronic Participation

    NARCIS (Netherlands)

    Tambouris, E.; Scholl, H.J.; Janssen, M.F.W.H.A.; Wimmer, M.A.; Tarabanis, K.; Gascó, M.; Klievink, A.J.; Lindgren, I.; Milano, M.; Panagiotopoulos, P.; Pardo, T.A.; Parycek, P.; Sæbø, O.

    2015-01-01

    Electronic government and electronic participation continue to transform the public sector and society worldwide and are constantly being transformed themselves by emerging information and communication technologies. This book presents papers from the 14th International Federation for Information

  7. Electronic Government and Electronic Participation

    NARCIS (Netherlands)

    Tambouris, E; Scholl, H.J.; Janssen, M.F.W.H.A.; Wimmer, M.A.; Tarabanis, K; Gascó, M; Klievink, A.J.; Lindgren, I; Milano, M; Panagiotopoulos, P; Pardo, T.A.; Parycek, P; Sæbø, Ø

    2016-01-01

    Electronic government and electronic participation continue to transform the public sector and society worldwide and are constantly being transformed themselves by emerging information and communication technologies.This book presents papers from the 14th International Federation for Information

  8. Tritrichomonas foetus adhere to superhydrophilic vertically aligned multi-walled carbon nanotube surface

    Energy Technology Data Exchange (ETDEWEB)

    Moreira Machado, Susane [Laboratorio de Biologia Celular e Tecidual, Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi 2911, 12244-000, Sao Jose dos Campos, SP (Brazil); Oliveira Lobo, Anderson, E-mail: loboao@yahoo.com [Laboratorio de Nanotecnologia Biomedica (NanoBio), Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, SP (Brazil); Laboratorio de Espectroscopia Vibracional Biomedica, Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Avenida Shishima Hifumi, 2911, CEP 12244-000, Sao Jose dos Campos, SP (Brazil); Bueno Loureiro Sapucahy, Ariel [Laboratorio de Biologia Celular e Tecidual, Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi 2911, 12244-000, Sao Jose dos Campos, SP (Brazil); Marciano, Fernanda Roberta [Laboratorio de Nanotecnologia Biomedica (NanoBio), Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, SP (Brazil); Laboratorio de Espectroscopia Vibracional Biomedica, Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Avenida Shishima Hifumi, 2911, CEP 12244-000, Sao Jose dos Campos, SP (Brazil); Corat, Evaldo Jose [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), Av. dos Astronautas 1758, Sao Jose dos Campos, 12227-010 SP (Brazil); Soares da Silva, Newton [Laboratorio de Biologia Celular e Tecidual, Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi 2911, 12244-000, Sao Jose dos Campos, SP (Brazil)

    2011-10-10

    For the first time, we show that Tritrichomonas foetus can adhere on superhydrophilic vertically aligned carbon nanotubes (VACNT) films. Scanning electron microscopy shows an unusual adhesion with a higher membrane filopodium projection in all directions, directly attached to superhydrophilic VACNT tips. Highlights: {yields} This is a new method to study the T. foetus adhesion mechanism. {yields} SEM images and interfacial adhesion force show a high adhesion level. {yields} It is very important for future understanding mechanism adhesion and protein expression.

  9. Attosecond electron-electron collision dynamics of the four-electron escape in Be close to threshold

    CERN Document Server

    Emmanouilidou, A

    2012-01-01

    We explore the escape geometry of four electrons a few eV above threshold following single-photon absorption from the ground state of Be. We find that the four electrons leave the atom on the vertices of a pyramid instead of a previously-predicted tetrahedron. To illustrate the physical mechanisms of quadruple ionization we use a momentum transferring attosecond collision scheme which we show to be in accord with the pyramid break-up pattern.

  10. Electron Tree

    DEFF Research Database (Denmark)

    Appelt, Ane L; Rønde, Heidi S

    2013-01-01

    The photo shows a close-up of a Lichtenberg figure – popularly called an “electron tree” – produced in a cylinder of polymethyl methacrylate (PMMA). Electron trees are created by irradiating a suitable insulating material, in this case PMMA, with an intense high energy electron beam. Upon discharge......, during dielectric breakdown in the material, the electrons generate branching chains of fractures on leaving the PMMA, producing the tree pattern seen. To be able to create electron trees with a clinical linear accelerator, one needs to access the primary electron beam used for photon treatments. We...... appropriated a linac that was being decommissioned in our department and dismantled the head to circumvent the target and ion chambers. This is one of 24 electron trees produced before we had to stop the fun and allow the rest of the accelerator to be disassembled....

  11. Autism spectrum disorder - childhood disintegrative disorder

    Science.gov (United States)

    ... part of the larger developmental disorder category of autism spectrum disorder . ... American Psychiatric Association. Autism spectrum disorder. ... ed. Arlington, VA: American Psychiatric Publishing: 2013;50-59. ...

  12. Topological Crystalline Insulator SnTe/Si Vertical Heterostructure Photodetectors for High-Performance Near-Infrared Detection.

    Science.gov (United States)

    Zhang, Hongbin; Man, Baoyuan; Zhang, Qi

    2017-04-26

    Due to the gapless surface state and narrow bulk band gap, the light absorption of topological crystalline insulators covers a broad spectrum ranging from terahertz to infrared, revealing promising applications in new generation optoelectronic devices. To date, the photodetectors based on topological insulators generally suffer from a large dark current and a weaker photocurrent especially under the near-infrared lights, which severely limits the practical application of devices. Owing to the lower excitation energy of infrared lights, the photodetection application of topological crystalline insulators in the near-infrared region relies critically on understanding the preparation and properties of their heterostructures. Herein, we fabricate the high-quality topological crystalline insulator SnTe film/Si vertical heterostructure by a simple physical vapor deposition process. The resultant heterostructure exhibits an excellent diode characteristic, enabling the construction of high-performance near-infrared photodetectors. The built-in electric field at SnTe/Si interface enhances the absorption efficiency of near-infrared lights and greatly facilitates the separation of photogenerated carriers, making the device capable of operating as a self-driven photodetector. The as-grown SnTe film acts as the hole transport layer in heterostructure photodetectors, promoting the transport of holes to electrode and reducing electron-hole recombination effectively. These merits enable the SnTe/Si heterostructure photodetector to have a high responsivity of 2.36 AW-1, a high detectivity of 1.54 × 1014 Jones, and a large bandwidth of 104 Hz in the near-infrared wavelength, which makes the detector have a promising market in novel device applications.

  13. Electron cloud dynamics in the Cornell Electron Storage Ring Test Accelerator wiggler

    Directory of Open Access Journals (Sweden)

    C. M. Celata

    2011-04-01

    Full Text Available The interference of stray electrons (also called “electron clouds” with accelerator beams is important in modern intense-beam accelerators, especially those with beams of positive charge. In magnetic wigglers, used, for instance, for transverse emittance damping, the intense synchrotron radiation produced by the beam can generate an electron cloud of relatively high density. In this paper the complicated dynamics of electron clouds in wigglers is examined using the example of a wiggler in the Cornell Electron Storage Ring Test Accelerator experiment at the Cornell Electron Storage Ring. Three-dimensional particle-in-cell simulations with the WARP-POSINST computer code show different density and dynamics for the electron cloud at locations near the maxima of the vertical wiggler field when compared to locations near the minima. Dynamics in these regions, the electron cloud distribution vs longitudinal position, and the beam coherent tune shift caused by the wiggler electron cloud will be discussed.

  14. Beyond the Spectrum: Rethinking Autism

    Directory of Open Access Journals (Sweden)

    Heather Thomas

    2017-03-01

    Full Text Available The "spectrum" has become the dominant metaphor for conceptualizing autism, with fundamental consequences for notions of disability, diversity, and normality. In this article, we draw on ethnographic research with autistic communities to explore how the notion of the autism spectrum has become a focus of explicit identification, reflection, and contestation. To further this inquiry, we place these debates into conversation with earlier debates regarding another spectrum—the Kinsey Scale, a "spectrum" for conceptualizing sexual orientation that first appeared in 1948 but has been critiqued since the 1970s. How might responses to the Kinsey Scale (like the Klein Grid contribute to rethinking the autism spectrum? This is a question about the cultural and political implications of metaphors and conceptual models. It is of broad importance because the spectrum metaphor is being extended to a range of conditions beyond autism itself. Our goal is thus to build on insights from sexuality studies as well as the insights of autistic persons, advocates, and researchers who wish to forestall the naturalization of "the spectrum." In doing so, we seek to contribute to a discussion of what alternative frameworks might bring to questions of social justice, ability, and human flourishing.

  15. The correction of occlusal vertical dimension on tooth wear

    Directory of Open Access Journals (Sweden)

    Rostiny Rostiny

    2007-12-01

    Full Text Available The loss of occlusal vertical dimension which is caused by tooth wear is necessarily treated to regain vertical dimension. Correctional therapy should be done as early possible. In this case, simple and relatively low cost therapy was performed. In unserve loss of occlusal vertical dimension, partial removable denture could be used and the improvement of lengthening anterior teeth using composite resin to improve to regain vertical dimensional occlusion.

  16. A position-sensitive electron detector for use in electron spectroscopy

    CERN Document Server

    Hubin-Franskin, M J

    2002-01-01

    A home-made position-sensitive electron detection system has been mounted on an electron energy loss spectrometer. It makes use of advanced technology, is easy to handle with and not too expensive. The K-shell excitation spectrum of benzene is given as an example of the quality of the signal-to-noise ratio while keeping the resolution.

  17. Electron cyclotron emission measurements on JET: Michelson interferometer, new absolute calibration, and determination of electron temperature

    NARCIS (Netherlands)

    Schmuck, S.; Fessey, J.; Gerbaud, T.; Alper, B.; Beurskens, M. N. A.; de la Luna, E.; Sirinelli, A.; Zerbini, M.

    2012-01-01

    At the fusion experiment JET, a Michelson interferometer is used to measure the spectrum of the electron cyclotron emission in the spectral range 70-500 GHz. The interferometer is absolutely calibrated using the hot/cold technique and, in consequence, the spatial profile of the plasma electron

  18. Analysis of vertical stability limits and vertical displacement event behavior on NSTX-U

    Science.gov (United States)

    Boyer, Mark; Battaglia, Devon; Gerhardt, Stefan; Menard, Jonathan; Mueller, Dennis; Myers, Clayton; Sabbagh, Steven; Smith, David

    2017-10-01

    The National Spherical Torus Experiment Upgrade (NSTX-U) completed its first run campaign in 2016, including commissioning a larger center-stack and three new tangentially aimed neutral beam sources. NSTX-U operates at increased aspect ratio due to the larger center-stack, making vertical stabilization more challenging. Since ST performance is improved at high elongation, improvements to the vertical control system were made, including use of multiple up-down-symmetric flux loop pairs for real-time estimation, and filtering to remove noise. Similar operating limits to those on NSTX (in terms of elongation and internal inductance) were achieved, now at higher aspect ratio. To better understand the observed limits and project to future operating points, a database of vertical displacement events and vertical oscillations observed during the plasma current ramp-up on NSTX/NSTX-U has been generated. Shots were clustered based on the characteristics of the VDEs/oscillations, and the plasma parameter regimes associated with the classes of behavior were studied. Results provide guidance for scenario development during ramp-up to avoid large oscillations at the time of diverting, and provide the means to assess stability of target scenarios for the next campaign. Results will also guide plans for improvements to the vertical control system. Work supported by U.S. D.O.E. Contract No. DE-AC02-09CH11466.

  19. Vertical stacking of InAs quantum dots for polarization-insensitive semiconductor optical amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, T; Asada, M; Kita, T; Wada, O [Department of Electrical and Electronic Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan); Yasuoka, N, E-mail: t_inoue@person.kobe-u.ac.j [Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0197 (Japan)

    2010-09-01

    In this paper, we report a control of the polarization property in quantum dot semiconductor optical amplifiers (QD-SOAs) using vertically-stacked, electronically-coupled InAs/GaAs QDs grown by molecular beam epitaxy. By optimizing the number of stacked layers and intermediate GaAs thickness, the 9-stacked QDs demonstrated the polarization-insensitive operation within 1.2 dB in the 1.3-mm optical communication band. Our results demonstrate that the electronically-coupled QDs are useful to realize the polarization-insensitive QD-SOAs.

  20. Vertically aligned ZnO nanorods on porous silicon substrates: Effect of growth time

    OpenAIRE

    R. Shabannia

    2015-01-01

    Vertically aligned ZnO nanorods were successfully grown on porous silicon (PS) substrates by chemical bath deposition at a low temperature. X-ray diffraction, field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and photoluminescence (PL) analyses were carried out to investigate the effect of growth duration (2 h to 8 h) on the optical and structural properties of the aligned ZnO nanorods. Strong and sharp ZnO (0 0 2) peaks of the ZnO nanorods proved th...

  1. Vertical emission profiles for Europe based on plume rise calculations

    NARCIS (Netherlands)

    Bieser, J.; Aulinger, A.; Matthias, V.; Quante, M.; Denier Van Der Gon, H.A.C.

    2011-01-01

    The vertical allocation of emissions has a major impact on results of Chemistry Transport Models. However, in Europe it is still common to use fixed vertical profiles based on rough estimates to determine the emission height of point sources. This publication introduces a set of new vertical

  2. Effect of vertical integration on the utilization of hardwood resources

    Science.gov (United States)

    Jan Wiedenbeck

    2002-01-01

    The effectiveness of vertical integration in promoting the efficient utilization of the hardwood resource in the eastern United States was assessed during a series of interviews with vertically integrated hardwood manufacturers in the Appalachian region. Data from 19 companies that responded to the 1996 phone survey indicate that: 1) vertically integrated hardwood...

  3. 49 CFR 179.14 - Coupler vertical restraint system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Coupler vertical restraint system. 179.14 Section... TANK CARS General Design Requirements § 179.14 Coupler vertical restraint system. (a) Performance... not be equipped with couplers having this vertical restraint capability. (b) Test verification. Except...

  4. aSPECT - Measuring the proton spectrum in neutron decay

    Energy Technology Data Exchange (ETDEWEB)

    Simson, Martin; Soldner, Torsten; Zimmer, Oliver [Institut Laue-Langevin, Grenoble (France); Physik-Department E18, TU Muenchen (Germany); Ayala Guardia, Fidel; Borg, Michael; Heil, Werner; Konrad, Gertrud; Munoz Horta, Raquel; Ostrick, Beatrix [Institut fuer Physik, Universitaet Mainz (Germany); Baessler, Stefan [University of Virginia, Charlottesville, VA (United States); Glueck, Ferenc [IEKP, Universitaet Karlsruhe (Germany); Konorov, Igor [Physik-Department E18, TU Muenchen (Germany); Wirth, Hans-Friedrich [Fakultaet fuer Physik, LMU Muenchen (Germany)

    2010-07-01

    With the aSPECT spectrometer we measure the proton recoil spectrum in the decay of the free neutron. Its shape depends on the angular correlation between the momenta of the antineutrino and electron for kinematic reasons. A precision measurement of this correlation coefficient a allows to test the unitarity of the CKM matrix and provides limits on the existence of scalar and tensor currents. aSPECT is a retardation spectrometer, this means protons from neutron decay are guided by a strong magnetic field and the proton recoil spectrum is measured by counting all protons that overcome a electrostatic barrier. By varying the height of the barrier the shape of the proton spectrum can be reconstructed. After the barrier the protons are accelerated to {proportional_to}15 keV and detected by a silicon drift detector. This talk covers details of the spectrometer and detector, as well as techniques used in the data analysis.

  5. High-Resolution Raindrop Size Distribution Retrieval Based on the Doppler Spectrum in the Case of Slant Profiling Radar

    NARCIS (Netherlands)

    Unal, C.M.H.

    2015-01-01

    Doppler spectra from vertically profiling radars are usually considered to retrieve the raindrop size distribution (DSD). However, to exploit both fall velocity spectrum and polarimetric measurements, Doppler spectra acquired in slant profiling mode should be explored. Rain DSD samples are obtained

  6. Power Electronics

    Indian Academy of Sciences (India)

    They cover a wide spectrum of areas from power supplies to power system ... in vehicles. In traction and automotive applications, other than the main propulsion drive itself, there are a number of auxiliary applications requiring electrical control and ... which can be a new solution for the differential drive in electric vehicles.

  7. Vertical deformation at western part of Sumatra

    Energy Technology Data Exchange (ETDEWEB)

    Febriyani, Caroline, E-mail: caroline.fanuel@students.itb.ac.id; Prijatna, Kosasih, E-mail: prijatna@gd.itb.ac.id; Meilano, Irwan, E-mail: irwan.meilano@gd.itb.ac.id

    2015-04-24

    This research tries to make advancement in GPS signal processing to estimate the interseismic vertical deformation field at western part of Sumatra Island. The data derived by Continuous Global Positioning System (CGPS) from Badan Informasi Geospasial (BIG) between 2010 and 2012. GPS Analyze at Massachusetts Institute of Technology (GAMIT) software and Global Kalman Filter (GLOBK) software are used to process the GPS signal to estimate the vertical velocities of the CGPS station. In order to minimize noise due to atmospheric delay, Vienna Mapping Function 1 (VMF1) is used as atmospheric parameter model and include daily IONEX file provided by the Center for Orbit Determination in Europe (CODE) as well. It improves GAMIT daily position accuracy up to 0.8 mm. In a second step of processing, the GLOBK is used in order to estimate site positions and velocities in the ITRF08 reference frame. The result shows that the uncertainties of estimated displacement velocity at all CGPS stations are smaller than 1.5 mm/yr. The subsided deformation patterns are seen at the northern and southern part of west Sumatra. The vertical deformation at northern part of west Sumatra indicates postseismic phase associated with the 2010 and 2012 Northern Sumatra earthquakes and also the long-term postseismic associated with the 2004 and 2005 Northern Sumatra earthquakes. The uplifted deformation patterns are seen from Bukit Tinggi to Seblat which indicate a long-term interseismic phase after the 2007 Bengkulu earthquake and 2010 Mentawai earthquake. GANO station shows a subsidence at rate 12.25 mm/yr, indicating the overriding Indo-Australia Plate which is dragged down by the subducting Southeast Asian Plate.

  8. Electronic Commerce

    Directory of Open Access Journals (Sweden)

    Slavko Đerić

    2016-12-01

    Full Text Available Electronic commerce can be defined in different ways. Any definition helps to understand and explain that concept as better as possible.. Electronic commerce is a set of procedures and technologies that automate the tasks of financial transactions using electronic means. Also, according to some authors, electronic commerce is defined as a new concept, which is being developed and which includes process of buying and selling or exchanging products, services or information via computer networks, including the Internet. Electronic commerce is not limited just to buying and selling, but it also includes all pre-sales and after-sales ongoing activities along the supply chain. Introducing electronic commerce, using the Internet and Web services in business, realizes the way to a completely new type of economy - internet economy.

  9. Vertically Polarized Omnidirectional Printed Slot Loop Antenna

    DEFF Research Database (Denmark)

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper

    2015-01-01

    A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...... pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due to the polarization....

  10. On triangle meshes with valence dominant vertices

    KAUST Repository

    Morvan, Jean-Marie

    2018-02-16

    We study triangulations $\\\\cal T$ defined on a closed disc $X$ satisfying the following condition: In the interior of $X$, the valence of all vertices of $\\\\cal T$ except one of them (the irregular vertex) is $6$. By using a flat singular Riemannian metric adapted to $\\\\cal T$, we prove a uniqueness theorem when the valence of the irregular vertex is not a multiple of $6$. Moreover, for a given integer $k >1$, we exhibit non isomorphic triangulations on $X$ with the same boundary, and with a unique irregular vertex whose valence is $6k$.

  11. Vertical profile measurements of lower troposphere ionisation

    OpenAIRE

    Harrison, R. G.; Nicoll, K.A.; Aplin, K. L.

    2014-01-01

    Vertical soundings of the atmospheric ion production rate have been obtained from Geiger counters integrated with conventional meteorological radiosondes. In launches made from Reading (UK) during 2013-2014, the Regener-Pfotzer ionisation maximum was at an altitude equivalent to a pressure of (63.1±2.4) hPa, or, expressed in terms of the local air density, (0.101±0.005) kgm−3. The measured ionisation profiles have been evaluated against the Usoskin-Kovaltsov model and, separately, surface neu...

  12. Vertical activity estimation using 2D radar

    CSIR Research Space (South Africa)

    Hakl, H

    2008-12-01

    Full Text Available update onto the information of the current update by projecting the possible positions of the aircraft against the radar sphere. Figure 1 illustrates this mapping in two dimensions for the sake of clarity and without loss of generality. Note... of the manoeuvre and delimits these with vertical. Note that some portions of Table 3 have been omitted. These sections have been deleted for the sake of brevity. The corresponding entries are all marked as accelerating by the system and do not contain further...

  13. Brand Equity and Vertical Product Line Extent

    OpenAIRE

    Taylor Randall; Karl Ulrich; David Reibstein

    1998-01-01

    This paper addresses the question of how the vertical structure of a product line relates to brand equity. Does the presence of “premium” or high-quality products in a product line enhance brand equity? Conversely, does the presence of “economy” or low-quality products in a product line diminish brand equity? Economists and marketing researchers refer to variation in quality levels of products within a category as “vertical” differentiation, whereas variation in the function or “category” of ...

  14. Vertical CNT-Si photodiode array.

    Science.gov (United States)

    Ahnood, Arman; Zhou, Hang; Dai, Qing; Vygranenko, Yuri; Suzuki, Yuji; Esmaeili-Rad, Mr; Amaratunga, Gehan; Nathan, Arokia

    2013-09-11

    A photodiode consisting of nanopillars of thin-film silicon p-i-n on an array of vertically aligned carbon nanotubes (CNTs) with a noncontinuous cathode electrode is demonstrated. The structure exploits the intrinsic enhancement of the CNTs' electric field, which leads to reduction in the photodiode's operating voltage and response time and enhancement of optical coupling due to better light trapping, as compared with the conventional planar photodiode. These improvements translate to higher resolution and higher frame rate flat-panel imaging systems for a broad range of applications, including computed tomography and particle detection.

  15. Vertical Meandering Approach for Antenna Size Reduction

    Directory of Open Access Journals (Sweden)

    Li Deng

    2012-01-01

    Full Text Available A novel vertical meandering technique to reduce the lateral size of a planar printed antenna is presented. It is implemented by dividing a conventional spiral patch into a different number of segments and placing them on different sides of the microwave substrate with vias as the connections. To confirm the validity of this technique, measured electrical performance and radiation characteristics of five antennas with different numbers of segments are compared. The smallest antenna is reduced in size by 84% when compared with the conventional printed spiral antenna.

  16. On the vertical structure of wind gusts

    DEFF Research Database (Denmark)

    Suomi, I.; Gryning, Sven-Erik; Floors, Rogier Ralph

    2015-01-01

    The increasing size of wind turbines, their height and the area swept by their blades have revised the need for understanding the vertical structure of wind gusts. Information is needed for the whole profile. In this study, we analyzed turbulence measurements from a 100m high meteorological mast...... at the Danish National Test Station for Large Wind Turbines at Høvsøre in Denmark. The site represents flat, homogeneous grassland with an average gust factor of 1.4 at 10m and 1.2 at 100m level. In a typical surface-layer gust parametrization, the gust factor is composed of two components, the peak factor...

  17. Opportunity's Surroundings on Sol 1818 (Vertical)

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends. This view is presented as a vertical projection with geometric seam correction. North is at the top. The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view. The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

  18. Probability distribution of vertical longitudinal shear fluctuations.

    Science.gov (United States)

    Fichtl, G. H.

    1972-01-01

    This paper discusses some recent measurements of third and fourth moments of vertical differences (shears) of longitudinal velocity fluctuations obtained in unstable air at the NASA 150 m meteorological tower site at Cape Kennedy, Fla. Each set of measurements consisted of longitudinal velocity fluctuation time histories obtained at the 18, 30, 60, 90, 120 and 150 m levels, so that 15 wind-shear time histories were obtained from each set of measurements. It appears that the distribution function of the longitudinal wind fluctuations at two levels is not bivariate Gaussian. The implications of the results relative to the design and operation of aerospace vehicles are discussed.-

  19. Propulsion systems for vertical flight aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, A.

    1990-01-01

    The present evaluation of VTOL airframe/powerplant integration configurations combining high forward flight speed with safe and efficient vertical flight identifies six configurations that can be matched with one of three powerplant types: turboshafts, convertible-driveshaft lift fans, and gas-drive lift fans. The airframes configurations are (1) tilt-rotor, (2) folded tilt-rotor, (3) tilt-wing, (4) rotor wing/disk wing, (5) lift fan, and (6) variable-diameter rotor. Attention is given to the lift-fan VTOL configuration. The evaluation of these configurations has been conducted by both a joint NASA/DARPA program and the NASA High Speed Rotorcraft program. 7 refs.

  20. Vertical Dynamic Stiffness of Offshore Foundations

    DEFF Research Database (Denmark)

    Latini, Chiara; Cisternino, Michele; Zania, Varvara

    2016-01-01

    Nowadays, pile and suction caisson foundations are widely used to support offshore structures which are subjected to vertical dynamic loads. The dynamic soil-structure interaction of floating foundations (foundations embedded in a soil layer whose height is greater than the foundation length......) is investigated by numerical analyses of representative finite element models. The 3D numerical model is compared and validated with existing analytical solutions. A parametric study is carried out analyzing the effect of the slenderness ratio Hp/d and the height and the stiffness of the soil layer on the dynamic...