WorldWideScience

Sample records for electron level crossings

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

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  2. Electron excitation cross sections of the 2p53s levels of neon

    International Nuclear Information System (INIS)

    Phillips, M.H.

    1982-01-01

    The electron excitation cross sections of the four 2p 5 3s levels of neon are measured by means of a new technique using laser induced fluorescenc. The values of both the apparent and direct excitatiuon cross sections are given as a function of incident electron energy (0-100eV for 1s 3 and 1s 5 metastable levels and 0-300 eV for the 1s 2 and 1s 4 resonance levels). The metastable levels are triplet states and their cross sections are sharply peaked. At the peak, 30 eV, the measured values of the cross sections are 0.59 x 10 -18 cm 2 for the 1s 3 level and 3.2 x 10 -18 cm 2 for the 1s 5 level. The 1s 2 and 1s 4 levels are mixtures of singlet and triplet states, and the cross sections are broad and peak at 60 eV. The apparent cross sections at 60 eV are 13.5 x 10 -18 cm 2 for the 1s 2 level and 2.9 x 10 -18 cm 2 for the 1s 4 level. Measurement of the atomic number density of each of the 1s levels is performed using the pulsed laser induced fluorescence. The measured values of the number density and the excitation cross section are used to obtain the lifetime of each level. The measured value of the reciprocal of the 1s 3 and 1s 5 lifetime is 1 x 10 5 s -1 . The 1s 2 and 1s 4 levels are radiation trapped, and the reciprocals of their lifetimes are 4 x 10 5 s -1 and 3 x 10 5 s -1 respectively. The electron excitation cross sections of the magnetic sublevels of each 1s level are obtained by measuring the polarization of the laser induced fluorescence as a function of laser polarization. The excitation cross sections of each of the magnetic sublevels within a particular 1s level are equal within experimental uncertainty

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

    International Nuclear Information System (INIS)

    Blanco Rames, F.

    1990-01-01

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

  4. Magnetic-sublevel cross sections for excitation of the n 1P levels of helium by electron impact

    International Nuclear Information System (INIS)

    Csanak, G.; Cartwright, D.C.; Trajmar, S.

    1992-01-01

    First-order many-body theory has been used to calculate collision-frame magnetic-sublevel differential cross sections for electron-impact excitation of the n 1 P (n=2,3,4,5,6) levels of helium for electrons with incident energy in the 25--500-eV range. By combining results from electron-impact differential-cross-section measurements and electron-photon coincidence measurements, experimental magnetic-sublevel cross sections have also been derived for the excitation of the 2 1 P and 3 1 P levels. The theory predicts a pronounced minimum for the M=0 magnetic-sublevel differential cross section for incident electron energies around 30 eV. Our theoretical results are compared to the experimental data and some other theoretical results

  5. Electron-impact excitation cross sections of the higher argon 3p5np (n=5,6,7) levels

    International Nuclear Information System (INIS)

    Weber, Tobin; Boffard, John B.; Lin, Chun C.

    2003-01-01

    We have measured the electron-impact excitation cross sections for argon into the ten levels of 3p 5 5p configuration, as well as numerous levels of the 3p 5 6p and 3p 5 7p configurations. Fluorescence from the decay of the excited atoms to the levels of 3p 5 4s configuration was used to determine the optical-emission cross sections. These results were combined with transition probabilities to find apparent cross sections into the 3p 5 5p and 3p 5 6p levels. These new cross sections of the Ar(3p 5 np) levels along with the available Ne(2p 5 3p), Kr(4p 5 5p), and Xe(5p 5 6p) data help provide a global view of the excitation behaviors of the np 5 n ' p levels of the rare-gas series

  6. Cross sections of electron excitation out of metastable helium levels with a fast metastable target product produced via charge exchange

    International Nuclear Information System (INIS)

    Lagus, M.E.; Boffard, J.B.; Anderson, L.W.; Lin, C.C.

    1996-01-01

    Absolute direct cross sections for electron excitation out of the 2 3 S level and into the 3 3 D, 4 3 D, and 3 3 S levels of the helium atom from threshold to 500 eV and into the 3 3 P level over a more limited energy range have been measured using a fast metastable atomic beam target. We produce the metastable atoms via near-resonant charge exchange between a 1.6-keV He + ion beam and Cs vapor. Because this reaction is highly nonresonant with the ground state of helium, the charge-transfer process yields a primarily metastable beam. We use a thermal detector which we calibrate with ions to measure absolutely the neutral beam flux. The atomic beam is crossed by an electron beam, and we collect the resulting fluorescence at right angles to both the electron and atomic beams. We obtain the cross sections for excitation out of the 2 3 S level into the various excited levels by monitoring the emission out of the excited level of interest. copyright 1996 The American Physical Society

  7. Level-resolved distorted-wave cross-sections of electron impact ionization of Ar{sup 5+}

    Energy Technology Data Exchange (ETDEWEB)

    Yumak, A; Yavuz, I; Altun, Z, E-mail: zikalt@superonline.co [Department of Physics, Marmara University, Istanbul, 34722 (Turkey)

    2009-11-01

    Electron impact ionization cross sections of Ar{sup 5+} were calculated using configuration-average (CADW) and level-resolved (LRDW) distorted-wave methods. Direct ionization cross-sections of 2s, 2p, 3s and 3p subshells were calculated within a CADW approximation. The contributions from the excitation autoionization channels were evaluated assuming single excitations from the 2s, 2p, and 3s subshells and in both CADW and LRDW methods. The radiative stabilization of the excitation autoionization channels were found to reduce the excitation autoionization by a small amount.

  8. The use of radiation trapping in the measurement of the electron excitation cross section for the production of the 1s4 (3P1) level of Ne

    International Nuclear Information System (INIS)

    Miers, R.E.; Gastineau, J.E.; Phillps, M.H.; Anderson, L.W.; Lin, C.C.

    1981-01-01

    The authors report the use of laser induced fluorescence for the first measurement of the electron excitation cross section for the production of the 1s 4 ( 3 P 1 ) level of Ne. Radiation trapping is used to lengthen the effective lifetime of the 1s 4 level allowing for the electron excitation cross section of the 1s 4 level to be measured in a manner similar to the measurement of electron excitation cross sections of the metastable 1s 3 and 1s 5 levels. (Auth.)

  9. Small rural emergency services can electronically collect accurate episode-level data: A cross-sectional study.

    Science.gov (United States)

    Dawson, Samantha L; Baker, Tim; Salzman, Scott

    2015-04-01

    There is little evidence that useful electronic data could be collected at Australian small rural emergency services. If in future their funding model changed to the Activity-Based Funding model, then they would need to collect and submit more data. We determine whether it is possible to collect episode-level data at six small rural emergency services and quantify the accuracy of eight fields. A prospective cross-sectional study. South-West Victoria, Australia. Six small rural emergency services. We collected and audited episode-level emergency data from participating services between 1 February 2011 and 31 January 2012. A random sample of these data were audited monthly. Research assistants located at each service supported data entry and audited data accuracy for four hours per week. Rates for data completeness, accuracy and total accuracy were calculated using audit data. Episode-level data were collected for 20 224 presentations across six facilities. The audit dataset consisted of 8.5% (1504/17 627) of presentations from five facilities. For all fields audited, the accuracy of entered data was high (>93%).Triage category was deemed appropriate for 95.9% (95% confidence interval (CI): 94.9-96.9%) of the patient records reviewed. Some procedures were missing (28.7%, 95%CI: 27.2-30.3%). No significant improvement in data accuracy over 12 months was observed. All six services collected useful episode-level data for 12-months with four hours per week of assistance. Data entry accuracy was high for all fields audited, and data entry completeness was low for procedures. © 2015 National Rural Health Alliance Inc.

  10. Cross sections for the vibrational excitation of the H2 X 1Σ+g(v) levels generated by electron collisional excitation of the higher singlet states

    International Nuclear Information System (INIS)

    Hiskes, J.R.

    1991-01-01

    The excitation cross sections, σ(v,v double-prime), for an H 2 molecule initially in any one of the 15 vibrational levels, v belonging to the ground electronic state and excited to a final vibrational level, v double-prime are evaluated for direct excitations via all members of the excited electronic singlet spectrum. Account is taken of predissociation, autoionization, and radiative decay of the excited electronic spectrum that leads to a final population distribution for the ground electronic state, X 1 Σ + g (v double-prime). For v=0, account is taken explicitly of transitions via the B, C, B', and D electronic states in evaluating the cross sections. The additional contribution of excitations via all Rydberg states lying above the D state enhances these cross sections by approximately 10%. For v>0, cross sections are evaluated taking explicit account of transitions through the B and C states; higher singlet excitations enhance these values by 25%. The choice of the reference total cross sections remains a subjective one, causing the values calculated here to have a possible uncertainty of +20% -30% . For excitations occurring within a hydrogen discharge, collisional excitation-ionization events among the intermediate singlet states will effectively quench the v, v double-prime excitation process for discharge densities in excess of the range 10 15 --10 16 electrons/cm -3

  11. Cross sections for electron-impact excitation of krypton from the levels of 4p6, 4p55s, and 4p55p configurations

    International Nuclear Information System (INIS)

    Zeng Jiaolong; Yuan Jianmin; Wu Jianhua; Jin Fengtao; Zhao Gang

    2005-01-01

    The electron-impact excitation cross sections at low electron energies have been calculated using a fully relativistic R-matrix method for transitions between levels of 4p 6 , 4p 5 5s, and 4p 5 5p configurations. To ensure the convergence of results, we have paid special attention to the factors that may affect the convergence of cross sections. For examples, we have included extensive configuration interactions in the wave-function expansion of the target states. A large enough R-matrix boundary has been taken to ensure the convergence of atomic wave functions. Contributions to cross sections from a large number of partial waves (up to J=39.5) have been explicitly calculated. The final results are in good agreement with recent experimental data by Jung et al. [Phys. Rev. Lett. 94, 163202 (2005)] after shifting the position of electron energy. The relative difference is about 10% for four transitions out of the metastable levels. The results eliminated the significant discrepancies between theory and experimental work on excitation cross sections out of the metastable levels reported in the literature

  12. Electron-impact cross sections of Ne

    International Nuclear Information System (INIS)

    Tsurubuchi, S.; Arakawa, K.; Kinokuni, S.; Motohashi, K.

    2000-01-01

    Electron-impact absolute emission cross sections were measured for the 3p→3s transitions of Ne. Excitation functions of the 3s→2p first resonance lines were measured in the energy range from the threshold to 1000 eV by a polarization-free optical method and relative cross sections were normalized to the absolute values, (41.0±5.4)x10 -19 cm 2 for the 73.6 nm line and (7.1±1.0)x10 -19 cm 2 for the 74.4 nm line, which were determined at 500 eV. The integrated level-excitation cross sections of Suzuki et al for the 1s 2 and 1s 4 levels were combined with the corresponding 3p→3s cascade cross sections obtained in this paper to give absolute emission cross sections for the resonance lines. The level-excitation cross sections of the 1s 2 and 1s 4 states in Paschen notation were determined from the threshold to 1000 eV by subtracting 3p→3s cascade cross sections from the corresponding 3s→2p emission cross sections of the resonance lines. A large cascade contribution is found in the emission cross section of the resonance lines. It is 28.5% for the 73.6 nm line and 49.6% for the 74.4 nm line at 40 eV, and 17.0 and 61.8%, respectively, at 300 eV. (author)

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  14. Electron attachment cross sections obtained from electron attachment spectroscopy

    International Nuclear Information System (INIS)

    Popp, P.; Baumbach, J.I.; Leonhardt, J.W.; Mothes, S.

    1988-01-01

    Electron capture detectors have a high sensitivity for substances with high thermal electron attachment cross sections. The electron attachment spectroscopy makes it possible to change the mean electron energy in such a way that the maximum for dissociative electron attachment is reached. Thus, best operation modes of the detection system as well as significant dependencies of electron attachment coefficients are available. Cross sections for electron attachment as a function of the electron energy are obtained with the knowledge of electron energy distribution functions from Boltzmann equation analysis by a special computer code. A disadvantage of this electron attachment spectroscopy is the superposition of space charge effects due to the decrease of the electron drift velocity with increasing mean electron energy. These influences are discussed. (author)

  15. Relativistic photon-Maxwellian electron cross sections

    International Nuclear Information System (INIS)

    Wienke, B.R.; Lathrop, B.L.; Devaney, J.J.

    1986-01-01

    Temperature corrected cross sections, complementing the Klein-Nishina set, are developed for astrophysical, plasma, and transport applications. The set is obtained from a nonlinear least squares fit to the exact photon-Maxwellian electron cross sections, using the static formula as the asymptotic basis. Two parameters are sufficient (two decimal places) to fit the exact cross sections over a range of 0-100 keV in electron temperature, and 0-1 MeV in incident photon energy. The fit is made to the total cross sections, yet the parameters predict both total and differential scattering cross sections well. Corresponding differential energy cross sections are less accurate. An extended fit to (just) the total cross sections, over the temperature and energy range 0-5 MeV, is also described. (author)

  16. Electron collision cross sections of mercury

    International Nuclear Information System (INIS)

    Suzuki, Susumu; Kuzuma, Kiyotaka; Itoh, Haruo

    2006-01-01

    In this paper, we propose a new collision cross section set for mercury which revises the original set summarized by Hayashi in 1989. Hanne reported three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) determined from an electron beam experiment in 1988. As a matter for regret, no attentive consideration was given to combining these three excitation cross sections with the cross section set of Hayashi. Therefore we propose a new set where these three excitation cross sections are included. In this study, other two excitation cross sections (6 1 P 1 , 6 3 D 3 ) except for the three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) are taken from the original set of Hayashi. The momentum transfer cross section and the ionization collision cross section are also taken from Hayashi. A Monte Carlo Simulation (MCS) technique is applied for evaluating our new cross section set. The present results of the electron drift velocity and the ionization coefficient are compared to experimental values. Agreement is secured in relation to the electron drift velocity for 1.5 Td 2 ) is the reduced electric field, E (V/cm) is the electric field, N (1/cm 3 ) is the number density of mercury atoms at 0degC, 1 Torr, E/N is also equal to 2.828 x 10 -17 E/p 0 from the relation of the ideal gas equation, p 0 (Torr) is gas pressure at 0degC, 1 Torr=1.33322 x 10 -2 N/cm -2 and 10 -17 V/cm 2 is called 1 Td. Thus it is ensured that our new cross section set is reasonable enough to be used up to 100 eV when considering with the electron drift velocity and the ionization coefficient. (author)

  17. Electron scattering cross sections pertinent to electron microscopy

    International Nuclear Information System (INIS)

    Inokuti, M.

    1978-01-01

    Some elements of the physics that determine cross sections are discussed, and various sources of data are indicated that should be useful for analytical microscopy. Atoms, molecules, and to some extent, solids are considered. Inelastic and elastic scattering of electrons and some solid-state effects are treated. 30 references

  18. Evaluation of the optical cross talk level in the SiPMs adopted in ASTRI SST-2M Cherenkov Camera using EASIROC front-end electronics

    International Nuclear Information System (INIS)

    Impiombato, D; Giarrusso, S; Mineo, T; Agnetta, G; Biondo, B; Catalano, O; Gargano, C; Rosa, G La; Russo, F; Sottile, G; Belluso, M; Billotta, S; Bonanno, G; Garozzo, S; Marano, D; Romeo, G

    2014-01-01

    ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana), is a flagship project of the Italian Ministry of Education, University and Research whose main goal is the design and construction of an end-to-end prototype of the Small Size of Telescopes of the Cherenkov Telescope Array. The prototype, named ASTRI SST-2M, will adopt a wide field dual mirror optical system in a Schwarzschild-Couder configuration to explore the VHE range of the electromagnetic spectrum. The camera at the focal plane is based on Silicon Photo-Multipliers detectors which is an innovative solution for the detection astronomical Cherenkov light. This contribution reports some preliminary results on the evaluation of the optical cross talk level among the SiPM pixels foreseen for the ASTRI SST-2M camera

  19. Electron Capture Cross Sections for Stellar Nucleosynthesis

    Directory of Open Access Journals (Sweden)

    P. G. Giannaka

    2015-01-01

    Full Text Available In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasiparticle random-phase approximation (pn-QRPA and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the abovementioned e--capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the 66Zn isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

  20. Electron collision cross sections and radiation chemistry

    International Nuclear Information System (INIS)

    Hatano, Y.

    1983-01-01

    A survey is given of the cross section data needs in radiation chemistry, and of the recent progress in electron impact studies on dissociative excitation of molecules. In the former some of the important target species, processes, and collision energies are presented, while in the latter it is demonstrated that radiation chemistry is a source of new ideas and information in atomic collision research. 37 references, 4 figures

  1. Electron-collision excitation cross section of the silver atom

    International Nuclear Information System (INIS)

    Krasavin, A.Y.; Kuchenev, A.N.; Smirnov, Y.M.

    1983-01-01

    The cross sections for direct excitation by electron collision were measured for fifteen transitions of the silver atom. For thirteen of these transitions the optical excitation functions were recorded, varying the energy of the exciting electrons from the threshold energy to 250 eV. The operating region of the spectrum was 2000--5500 A. The excitation cross sections of the two principal lines exceeded the excitation cross sections of all the remaining lines by more than an order of magnitude. Reabsorption of the resonance lines was detected from the change in the ratio of intensities of the lines at 3280.68 and 3382.89 A, and so their intensity has been corrected relative to the intensities of the nonreabsorbed lines. All radiative transitions, with the exception of resonance transitions, participate in cascade population of the lowest resonance levels, making it possible to determine the resulting direct excitation cross sections of the 5p 2 P/sub 1/2/ and 5p 2 P/sub 3/2/ levels from the ground state of the silver atom. The part played by cascade population of the resonance levels is not large and is 2 P/sub 3/2/ level, and 10% for the 5p 2 P/sub 1/2/ level, of the excitation cross sections of the corresponding resonance transitions

  2. Level crossing analysis of growing surfaces

    International Nuclear Information System (INIS)

    Shahbazi, F; Sobhanian, S; Tabar, M Reza Rahimi; Khorram, S; Frootan, G R; Zahed, H

    2003-01-01

    We investigate the average frequency of positive slope ν + α , crossing the height α = h - h-bar in the surface growing processes. The exact level crossing analysis of the random deposition model and the Kardar-Parisi-Zhang equation in the strong coupling limit before creation of singularities is given

  3. Electron-collision cross sections for iodine

    International Nuclear Information System (INIS)

    Zatsarinny, O.; Bartschat, K.; Garcia, G.; Blanco, F.; Hargreaves, L.R.; Jones, D.B.; Murrie, R.; Brunton, J.R.; Brunger, M.J.; Hoshino, M.; Buckman, S.J.

    2011-01-01

    We present results from a joint experimental and theoretical study of elastic electron scattering from atomic iodine. The experimental results were obtained by subtracting known cross sections from the measured data obtained with a pyrolyzed mixed beam containing a variety of atomic and molecular species. The calculations were performed using both a fully relativistic Dirac B-spline R-matrix (close-coupling) method and an optical model potential approach. Given the difficulty of the problem, the agreement between the two sets of theoretical predictions and the experimental data for the angle-differential and the angle-integrated elastic cross sections at 40 eV and 50 eV is satisfactory.

  4. Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

    Science.gov (United States)

    Jones, D. B.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; Blanco, F.; García, G.; Brunger, M. J.

    2016-04-01

    We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20-250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron-furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.

  5. Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Costa, R. F. da [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, 13083-859 São Paulo (Brazil); Departamento de Física, Universidade Federal do Espírito Santo, 29075-910, Vitória, Espírito Santo (Brazil); Varella, M. T. do N. [Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970 São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Lima, M. A. P. [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, 13083-859 São Paulo (Brazil); Blanco, F. [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040 (Spain); García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2016-04-14

    We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20–250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron–furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.

  6. Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

    International Nuclear Information System (INIS)

    Jones, D. B.; Costa, R. F. da; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; Blanco, F.; García, G.; Brunger, M. J.

    2016-01-01

    We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20–250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron–furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.

  7. Compilation of electron collision excitation cross sections for neutral argon

    International Nuclear Information System (INIS)

    Blanco, F.

    1993-01-01

    The present work presents a compilation and critical analysis of the available data on electron collision excitation cross sections for neutral Argon levels. This study includes: 1.- A detailed description in intermediate coupling for all the levels belonging the 20 configurations 3p5 ns (n=4to 12), np(n=4to8) and nd(n=3to8)of neutral Argon. 2.- Calculation of the electron collision excitation cross sections in Born and Born-Oppenheimer-Ochkur approximations for all the levels in the 14 configurations 3p5 ns (n=4 to 7), np (n=4 to 7) and nd (n=3 to 8). 3.- comparison and discussion of the compiled data. These are the experimental and theoretical values available from the literature, and those from this work. 4.- Analysis of the regularities and systematic behaviors in order to determine which values can be considered more reliable. It is show that the concept of one electron cross section results quite useful for this purpose. In some cases it has been possible to obtain in this way approximate analytical expressions interpolating the experimental data. 5.- All the experimental and theoretical values studied are graphically presented and compared. 6.- The last part of the work includes a listing of several general purpose programs for Atomic Physics calculations developed for this work. (Author) 35 refs

  8. Compilation of electron collision excitation cross sections for neutro argon

    International Nuclear Information System (INIS)

    Blanco Ramos, F.

    1993-01-01

    The present work presents a compilation and critical analysis of the available data on electron collision excitation cross sections for neutral Argon levels. This study includes: 1.- A detailed description in intermediate coupling for all the levels belonging the 20 configurations 3p''5 ns(n=4 to 12), np(n=4 to 8) and nd(n=3 to 8) of neutral Argon. 2.- Calculation of the electron collision excitation cross sections in Born and Born-Oppenheimer-Ochkur approximations for all the levels in the 14 configurations 3p''5 ns(n=4 to 7), np(n=4 to 7) and nd(n=3 to 8). 3.- Comparison and discussion of the compiled data. These are the experimental and theoretical values available from the literature, and those from this work. 4.- Analysis of the regularities and systematic behaviors in order to determine which values can be considered more reliable. It is show that the concept of one electron cross section results quite useful for this purpose. In some cases it has been possible to obtain in this way approximate analytical expressions interpolating the experimental data. 5.- All the experimental and theoretical values studied are graphically presented and compared. 6.- The last part of the work includes a listing of several general purpose programs for Atomic Physics calculations developed for this work. (Author)

  9. Integral cross sections for electron impact excitation of vibrational and electronic states in phenol

    Energy Technology Data Exchange (ETDEWEB)

    Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Instituto Federal do Sul de Minas Gerais, Campus Poços de Caldas, Minas Gerais (Brazil); Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Blanco, F. [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, 28040 Madrid (Spain); García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); Ratnavelu, K. [Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-05-21

    We report on measurements of integral cross sections (ICSs) for electron impact excitation of a series of composite vibrational modes and electronic-states in phenol, where the energy range of those experiments was 15–250 eV. There are currently no other results against which we can directly compare those measured data. We also report results from our independent atom model with screened additivity rule correction computations, namely, for the inelastic ICS (all discrete electronic states and neutral dissociation) and the total ionisation ICS. In addition, for the relevant dipole-allowed excited electronic states, we also report f-scaled Born-level and energy-corrected and f-scaled Born-level (BEf-scaled) ICS. Where possible, our measured and calculated ICSs are compared against one another with the general level of accord between them being satisfactory to within the measurement uncertainties.

  10. Electronic properties of carbon nanotubes with polygonized cross sections

    International Nuclear Information System (INIS)

    Charlier, J.; Lambin, P.; Ebbesen, T.

    1996-01-01

    The electronic properties of carbon nanotubes having polygonized cross sections instead of purely circular ones, such as recently observed using transmission electron microscopy, are investigated with plane-wave ab initio pseudopotential local-density-functional calculations and simple tight-binding models. Strong σ * -π * hybridization effects occur in zigzag nanotubes due to the high curvature located near the edges of the polygonal cross-section prism. These effects, combined with a lowering of symmetry, dramatically affect the electronic properties of the nanotubes. It is found that modified low-lying conduction-band states are introduced either into the bandgap of insulating nanotubes, or below the degenerate states that form the top of the valence band of metallic nanotubes, leading the corresponding nanostructures to be metals, semimetals, or at least very-small-gap semiconductors. The degree of the polygon representing the cross section of the tube, and the sharpness of the edge angles, are found to be major factors in the hybridization effect, and consequently govern the electronic behavior at the Fermi level. copyright 1996 The American Physical Society

  11. The Power of Cross-Level Partnerships.

    Science.gov (United States)

    Youngerman, Stephanie

    1998-01-01

    Much credit for the tangible feeling of caring at an Idaho elementary school is due to partnerships that faculty, families, and students have forged across grade levels. These cross-grade buddy systems have put the brakes on bullies, fostered student friendships, and resolved personality conflicts among staff members. (MLH)

  12. Cross-field Mobility in a Pure Electron Plasma

    International Nuclear Information System (INIS)

    Fossum, E.C.; King, L.B.

    2006-01-01

    An electron trapping apparatus was constructed in order to study electron dynamics in the defining electric and magnetic field of a Hall-effect thruster. The approach presented here decouples the cross-field mobility from plasma effects by conducting measurements on a pure electron plasma in a highly controlled environment. Dielectric walls are removed completely eliminating all wall effect; thus, electrons are confined solely by a radial magnetic field and a crossed, independently-controlled, axial electric field that induces the closed-drift azimuthal Hall current. Electron trajectories and cross-field mobility were examined in response to electric and magnetic field strength and background neutral density

  13. Modelling of Signal - Level Crossing System

    Directory of Open Access Journals (Sweden)

    Daniel Novak

    2006-01-01

    Full Text Available The author presents an object-oriented model of a railway level-crossing system created for the purpose of functional requirements specification. Unified Modelling Language (UML, version 1.4, which enables specification, visualisation, construction and documentation of software system artefacts, was used. The main attention was paid to analysis and design phases. The former phase resulted in creation of use case diagrams and sequential diagrams, the latter in creation of class/object diagrams and statechart diagrams.

  14. Large level crossings of a random polynomial

    Directory of Open Access Journals (Sweden)

    Kambiz Farahmand

    1987-01-01

    Full Text Available We know the expected number of times that a polynomial of degree n with independent random real coefficients asymptotically crosses the level K, when K is any real value such that (K2/n→0 as n→∞. The present paper shows that, when K is allowed to be large, this expected number of crossings reduces to only one. The coefficients of the polynomial are assumed to be normally distributed. It is shown that it is sufficient to let K≥exp(nf where f is any function of n such that f→∞ as n→∞.

  15. Absolute elastic cross sections for electron scattering from SF6

    International Nuclear Information System (INIS)

    Gulley, R.J.; Uhlmann, L.J.; Dedman, C.J.; Buckman, S.J.; Cho, H.; Trantham, K.W.

    2000-01-01

    Full text: Absolute differential cross sections for vibrationally elastic scattering of electrons from sulphur hexafluoride (SF 6 ) have been measured at fixed angles of 60 deg, 90 deg and 120 deg over the energy range of 5 to 15 eV, and also at 11 fixed energies between 2.7 and 75 eV for scattering angles between 10 deg and 180 deg. These measurements employ the magnetic angle-changing technique of Read and Channing in combination with the relative flow technique to obtain absolute elastic scattering cross sections at backward angles (135 deg to 180 deg) for incident energies below 15 eV. The results reveal some substantial differences with several previous determinations and a reasonably good level of agreement with a recent close coupling calculation

  16. Compact fitting formulas for electron-impact cross sections

    International Nuclear Information System (INIS)

    Kim, Y.K.

    1992-01-01

    Compact fitting formulas, which contain four fitting constants, are presented for electron-impact excitation and ionization cross sections of atoms and ions. These formulas can fit experimental and theoretical cross sections remarkably well, when resonant structures are smoothed out, from threshold to high incident electron energies (<10 keV), beyond which relativistic formulas are more appropriate. Examples of fitted cross sections for some atoms and ions are presented. The basic form of the formula is valid for both atoms and molecules

  17. Effect of Secondary Electron Emission on Electron Cross-Field Current in E×B Discharges

    Energy Technology Data Exchange (ETDEWEB)

    Yevgeny Raitses, Igor D. Kaganovich, Alexander Khrabrov, Dmytro Sydorenko, Nathaniel J. Fisch and Andrei Smolyakov

    2011-02-10

    This paper reviews and discusses recent experimental, theoretical, and numerical studies of plasma-wall interaction in a weakly collisional magnetized plasma bounded with channel walls made from different materials. A lowpressure ExB plasma discharge of the Hall thruster was used to characterize the electron current across the magnetic field and its dependence on the applied voltage and electron-induced secondary electron emission (SEE) from the channel wall. The presence of a depleted, anisotropic electron energy distribution function with beams of secondary electrons was predicted to explain the enhancement of the electron cross-field current observed in experiments. Without the SEE, the electron crossfield transport can be reduced from anomalously high to nearly classical collisional level. The suppression of SEE was achieved using an engineered carbon velvet material for the channel walls. Both theoretically and experimentally, it is shown that the electron emission from the walls can limit the maximum achievable electric field in the magnetized plasma. With nonemitting walls, the maximum electric field in the thruster can approach a fundamental limit for a quasineutral plasma.

  18. Effect of Secondary Electron Emission on Electron Cross-Field Current in E x B Discharges

    International Nuclear Information System (INIS)

    Raitses, Yevgeny; Kaganovich, Igor D.; Khrabrov, Alexander; Sydorenko, Dmytro; Fisch, Nathaniel J.; Smolyakov, Andrei

    2011-01-01

    This paper reviews and discusses recent experimental, theoretical, and numerical studies of plasma-wall interaction in a weakly collisional magnetized plasma bounded with channel walls made from different materials. A lowpressure ExB plasma discharge of the Hall thruster was used to characterize the electron current across the magnetic field and its dependence on the applied voltage and electron-induced secondary electron emission (SEE) from the channel wall. The presence of a depleted, anisotropic electron energy distribution function with beams of secondary electrons was predicted to explain the enhancement of the electron cross-field current observed in experiments. Without the SEE, the electron crossfield transport can be reduced from anomalously high to nearly classical collisional level. The suppression of SEE was achieved using an engineered carbon velvet material for the channel walls. Both theoretically and experimentally, it is shown that the electron emission from the walls can limit the maximum achievable electric field in the magnetized plasma. With nonemitting walls, the maximum electric field in the thruster can approach a fundamental limit for a quasineutral plasma.

  19. Portfolio Selection Using Level Crossing Analysis

    Science.gov (United States)

    Bolgorian, Meysam; Shirazi, A. H.; Jafari, G. R.

    Asset allocation is one of the most important and also challenging issues in finance. In this paper using level crossing analysis we introduce a new approach for portfolio selection. We introduce a portfolio index that is obtained based on minimizing the waiting time to receive known return and risk values. By the waiting time, we mean time that a special level is observed in average. The advantage of this approach is that the investors are able to set their goals based on gaining return and knowing the average waiting time and risk value at the same time. As an example we use our model for forming portfolio of stocks in Tehran Stock Exchange (TSE).

  20. Cross sections for collisions of subexcitation electrons with molecules

    International Nuclear Information System (INIS)

    Itikawa, Y.

    1983-01-01

    A short review is given on the present knowledge about the collision processes of subexcitation electrons (i.e., electrons whose energy is below the threshold of the first electronically excited state) with molecules. The processes considered are: vibrational and rotational excitations and elastic scattering. As an example, stopping cross sections for those processes (and electronic excitation and ionization, for comparison) are shown graphically for N 2 and H 2 O. 21 references, 2 figures

  1. Manufacture of polyethylene foam by electron beam cross-linking

    International Nuclear Information System (INIS)

    Tamai, Isamu

    1976-01-01

    The manufacturing process of polyethylene foam, comparison between electron beam cross-linking process and chemical cross-linking process, the electron beam irradiation technique for continuous sheets, the characteristics and uses of polyethylene foam are reviewed. The pore diameter can be controlled by selecting the dose rate, because there is strong relationship between the pore diameter and the dose rate. As the dose if higher, the foam becomes finer. The electron accelerators having large capacity show the lowest cost as the radiation source, and are applicable industrially. If the production capacity exceeds about 200 tons per month, the costs of electron beam irradiation process may be more advantageous than that of chemical process according to the circumstances. It is difficult to obtain the uniform distribution of absorption dose in the direction of thickness. General characteristics of cross-linked polyethylene foam are listed. The special feature of electron beam process is that the degree of cross-linking can be controlled arbitrarily before foaming. The products obtained by the electron beam cross-linking process have finer foams and smoother surfaces than those obtained by the chemical process, because the separation of the decomposition of foaming agents from that of cross-linking agents in the chemical cross-linking is difficult. (Iwakiri, K.)

  2. Investigation of privatization by level crossing approach

    Science.gov (United States)

    Vahabi, M.; Jafari, G. R.

    2009-09-01

    Privatization - a political as well as an economic policy - is generally defined as the transfer of a property or the responsibility for it from the public to the private sector. But privatization is not merely the transfer of the ownership and efficiency of the market should be considered. A successful privatization program induces better profitability and efficiency, higher output, more investment, etc. The main method of privatization is through introducing new stocks to the market to motivate competition. However, for a successful privatization the capability of a market for absorbing the new stock should also be considered. Without paying attention to this aspect, privatization through the introduction of new stocks may lead to reduced market efficiency. We study, based on the complexity theory and in particular the concept of Level Crossing, the effect of the stages of the development, activity, risk, and the waiting times for special events on the privatization.

  3. Electron collision cross section sets of TMS and TEOS vapours

    Science.gov (United States)

    Kawaguchi, S.; Takahashi, K.; Satoh, K.; Itoh, H.

    2017-05-01

    Reliable and detailed sets of electron collision cross sections for tetramethylsilane [TMS, Si(CH3)4] and tetraethoxysilane [TEOS, Si(OC2H5)4] vapours are proposed. The cross section sets of TMS and TEOS vapours include 16 and 20 kinds of partial ionization cross sections, respectively. Electron transport coefficients, such as electron drift velocity, ionization coefficient, and longitudinal diffusion coefficient, in those vapours are calculated by Monte Carlo simulations using the proposed cross section sets, and the validity of the sets is confirmed by comparing the calculated values of those transport coefficients with measured data. Furthermore, the calculated values of the ionization coefficient in TEOS/O2 mixtures are compared with measured data to confirm the validity of the proposed cross section set.

  4. Theoretical and experimental differential cross sections for electron impact excitation of the electronic bands of furfural

    Science.gov (United States)

    Jones, D. B.; Neves, R. F. C.; Lopes, M. C. A.; da Costa, R. F.; do N. Varella, M. T.; Bettega, M. H. F.; Lima, M. A. P.; García, G.; Limão-Vieira, P.; Brunger, M. J.

    2016-03-01

    We report results from a joint experimental and theoretical investigation into electron scattering from the important industrial species furfural (C5H4O2). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C5H4O2. The measurements were carried out at energies in the range 20-40 eV, and for scattered-electron angles between 10° and 90°. The energy resolution of those experiments was typically ˜80 meV. Corresponding Schwinger multichannel method with pseudo-potential calculations, for energies between 6-50 eV and with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were undertaken at the static exchange plus polarisation-level using a minimum orbital basis for single configuration interaction (MOB-SCI) approach. Agreement between the measured and calculated DCSs was qualitatively quite good, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOB-SCI. The role of multichannel coupling on the computed electronic-state DCSs is also explored in some detail.

  5. Theoretical and experimental differential cross sections for electron impact excitation of the electronic bands of furfural

    International Nuclear Information System (INIS)

    Jones, D. B.; Neves, R. F. C.; Lopes, M. C. A.; Costa, R. F. da; Varella, M. T. do N; Bettega, M. H. F.; Lima, M. A. P.; García, G.

    2016-01-01

    We report results from a joint experimental and theoretical investigation into electron scattering from the important industrial species furfural (C 5 H 4 O 2 ). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C 5 H 4 O 2 . The measurements were carried out at energies in the range 20–40 eV, and for scattered-electron angles between 10° and 90°. The energy resolution of those experiments was typically ∼80 meV. Corresponding Schwinger multichannel method with pseudo-potential calculations, for energies between 6–50 eV and with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were undertaken at the static exchange plus polarisation-level using a minimum orbital basis for single configuration interaction (MOB-SCI) approach. Agreement between the measured and calculated DCSs was qualitatively quite good, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOB-SCI. The role of multichannel coupling on the computed electronic-state DCSs is also explored in some detail.

  6. Theoretical and experimental differential cross sections for electron impact excitation of the electronic bands of furfural

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Neves, R. F. C. [Instituto Federal do Sul de Minas Gerais, Câmpus Poços de Caldas, Minas Gerais (Brazil); Departamento de Física, UFJF, Juiz de Fora, Minas Gerais 36036-900 (Brazil); Lopes, M. C. A. [Departamento de Física, UFJF, Juiz de Fora, Minas Gerais 36036-900 (Brazil); Costa, R. F. da [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, São Paulo 09210-580 (Brazil); Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, São Paulo 13083-859 (Brazil); Varella, M. T. do N [Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970 São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, CP 19044, Curitiba, Paraná 81531-990 (Brazil); Lima, M. A. P., E-mail: maplima@ifi.unicamp.br [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, São Paulo 13083-859 (Brazil); García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); and others

    2016-03-28

    We report results from a joint experimental and theoretical investigation into electron scattering from the important industrial species furfural (C{sub 5}H{sub 4}O{sub 2}). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C{sub 5}H{sub 4}O{sub 2}. The measurements were carried out at energies in the range 20–40 eV, and for scattered-electron angles between 10° and 90°. The energy resolution of those experiments was typically ∼80 meV. Corresponding Schwinger multichannel method with pseudo-potential calculations, for energies between 6–50 eV and with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were undertaken at the static exchange plus polarisation-level using a minimum orbital basis for single configuration interaction (MOB-SCI) approach. Agreement between the measured and calculated DCSs was qualitatively quite good, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOB-SCI. The role of multichannel coupling on the computed electronic-state DCSs is also explored in some detail.

  7. Total and ionization cross sections of electron scattering by fluorocarbons

    International Nuclear Information System (INIS)

    Antony, B K; Joshipura, K N; Mason, N J

    2005-01-01

    Electron impact total cross sections (50-2000 eV) and total ionization cross sections (threshold to 2000 eV) are calculated for typical plasma etching molecules CF 4 , C 2 F 4 , C 2 F 6 , C 3 F 8 and CF 3 I and the CF x (x 1-3) radicals. The total elastic and inelastic cross sections are determined in the spherical complex potential formalism. The sum of the two gives the total cross section and the total inelastic cross section is used to calculate the total ionization cross sections. The present total and ionization cross sections are found to be consistent with other theories and experimental measurements, where they exist. Our total cross section results for CF x (x = 1-3) radicals presented here are first estimates on these species

  8. Discussion of electron cross sections for transport calculations

    International Nuclear Information System (INIS)

    Berger, M.J.

    1983-01-01

    This paper deals with selected aspects of the cross sections needed as input for transport calculations and for the modeling of radiation effects in biological materials. Attention is centered mainly on the cross sections for inelastic interactions between electrons and water molecules and the use of these cross sections for the calculation of energy degradation spectra and of ionization and excitation yields. 40 references, 3 figures, 1 table

  9. Investigation of Electronic Corrosion at Device Level

    DEFF Research Database (Denmark)

    Jellesen, Morten Stendahl; Minzari, Daniel; Rathinavelu, Umadevi

    2010-01-01

    This work presents device level testing of a lead free soldered electronic device tested with bias on under cyclic humidity conditions in a climatic chamber. Besides severe temperature and humidity during testing some devices were deliberately contaminated before testing. Contaminants investigated...

  10. Applications of cross sections for electron-molecule collision processes

    International Nuclear Information System (INIS)

    Cartwright, D.C.

    1985-01-01

    The role of electron-molecule collision cross sections is discussed for the study of the ionospheric and auroral processes in planetary atmospheres and of discharge-pumped lasers. These two areas emphasize the importance of further theoretical and experimental studies concerning electron-impact processes. 13 refs., 3 figs., 2 tabs

  11. Exchange corrections to the bulk plasmon cross section of slow electrons in metals

    International Nuclear Information System (INIS)

    Yin, S.; Goodman, B.; Tosatti, E.

    1981-08-01

    We present a calculation of the simplest exchange correction to the low-energy electron cross section for plasmon creation in a free-electron-like metal with the density of Al. The resulting cancellation effect is found to be much too small to account for the anomalous delayed onset of plasmon losses, found in core level photo emission for Al. (author)

  12. Electron-impact excitation out of the metastable levels of Krypton

    International Nuclear Information System (INIS)

    Jung, R.O.; Stone, Tom E.; Boffard, John B.; Anderson, L.W.; Lin, Chun C.

    2005-01-01

    We have measured the electron-impact excitation cross sections out of the two metastable levels of Kr into the ten levels of the 4p 5 5p configuration. For a common 4p 5 5p final level, the peak excitation cross sections out of the two individual 4p 5 5s metastable levels are found to differ by 1 to 2 orders of magnitude. This is explained by the special features of the electronic structure of the two configurations involved. The peak cross sections are 10 to 1600 times larger than the corresponding peak cross sections out of the ground state

  13. Electron collision cross sections and electron swarm parameters for gas molecules

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    1986-01-01

    Elastic and inelastic electron collision cross sections for molecules which interest in radiation research have been determined from available electron beam and electron swarm data by utilizing the Boltzmann equation and Monte Carlo simulation method. Electron drift velocity data which interest in radiation Pysics have been discussed and some calculated results of electron drift velocity data for CF 4 and CF 4 -inert gases mixtures will be presented. (author)

  14. Differential cross sections for electron impact excitation of the electronic bands of phenol

    Energy Technology Data Exchange (ETDEWEB)

    Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Instituto Federal do Sul de Minas Gerais, Campus Poços de Caldas, Minas Gerais (Brazil); Departamento de Física, UFJF, Juiz de Fora, Minas Gerais (Brazil); Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Lopes, M. C. A.; Nixon, K. L. [Departamento de Física, UFJF, Juiz de Fora, Minas Gerais (Brazil); Silva, G. B. da [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Departamento de Física, UFJF, Juiz de Fora, Minas Gerais (Brazil); Oliveira, E. M. de; Lima, M. A. P. [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo (Brazil); Costa, R. F. da [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, São Paulo (Brazil); Varella, M. T. do N. [Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970 São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); and others

    2015-03-14

    We report results from a joint theoretical and experimental investigation into electron scattering from the important organic species phenol (C{sub 6}H{sub 5}OH). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C{sub 6}H{sub 5}OH. The measurements were carried out at energies in the range 15–40 eV, and for scattered-electron angles between 10{sup ∘} and 90{sup ∘}. The energy resolution of those experiments was typically ∼80 meV. Corresponding Schwinger multichannel method with pseudo-potentials calculations, with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were conducted at the static exchange plus polarisation (SEP)-level using a minimum orbital basis for single configuration interaction (MOBSCI) approach. Agreement between the measured and calculated DCSs was typically fair, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOBSCI.

  15. Anomalous fermion number nonconservation: Paradoxes in the level crossing picture

    International Nuclear Information System (INIS)

    Burnier, Y.

    2006-01-01

    In theories with anomalous fermion number nonconservation, the level-crossing picture is considered a faithful representation of the fermionic quantum number variation. It represents each created fermion by an energy level that crosses the zero-energy line from below. If several fermions of various masses are created, the level-crossing picture contains several levels that cross the zero-energy line and cross each other. However, we know from quantum mechanics that the corresponding levels cannot cross if the different fermions are mixed via some interaction potential. The simultaneous application of these two requirements on the level behavior leads to paradoxes. For instance, a naive interpretation of the resulting level-crossing picture gives rise to charge nonconservation. In this paper, we resolve this paradox by a precise calculation of the transition probability, and discuss what are the implications for the electroweak theory. In particular, the nonperturbative transition probability is higher if top quarks are present in the initial state

  16. Cross Sections for Inner-Shell Ionization by Electron Impact

    Energy Technology Data Exchange (ETDEWEB)

    Llovet, Xavier, E-mail: xavier@ccit.ub.edu [Centres Científics i Tecnològics, Universitat de Barcelona, Lluís Solé i Sabarís 1-3, 08028 Barcelona (Spain); Powell, Cedric J. [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8370 (United States); Salvat, Francesc [Facultat de Física (ECM and ICC), Universitat de Barcelona, Diagonal 645, 08028 Barcelona (Spain); Jablonski, Aleksander [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland)

    2014-03-15

    An analysis is presented of measured and calculated cross sections for inner-shell ionization by electron impact. We describe the essentials of classical and semiclassical models and of quantum approximations for computing ionization cross sections. The emphasis is on the recent formulation of the distorted-wave Born approximation by Bote and Salvat [Phys. Rev. A 77, 042701 (2008)] that has been used to generate an extensive database of cross sections for the ionization of the K shell and the L and M subshells of all elements from hydrogen to einsteinium (Z = 1 to Z = 99) by electrons and positrons with kinetic energies up to 1 GeV. We describe a systematic method for evaluating cross sections for emission of x rays and Auger electrons based on atomic transition probabilities from the Evaluated Atomic Data Library of Perkins et al. [Lawrence Livermore National Laboratory, UCRL-ID-50400, 1991]. We made an extensive comparison of measured K-shell, L-subshell, and M-subshell ionization cross sections and of Lα x-ray production cross sections with the corresponding calculated cross sections. We identified elements for which there were at least three (for K shells) or two (for L and M subshells) mutually consistent sets of cross-section measurements and for which the cross sections varied with energy as expected by theory. The overall average root-mean-square deviation between the measured and calculated cross sections was 10.9% and the overall average deviation was −2.5%. This degree of agreement between measured and calculated ionization and x-ray production cross sections was considered to be very satisfactory given the difficulties of these measurements.

  17. Single-level resonance parameters fit nuclear cross-sections

    Science.gov (United States)

    Drawbaugh, D. W.; Gibson, G.; Miller, M.; Page, S. L.

    1970-01-01

    Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total.

  18. Total cross sections for positron and electron scattering from pyrimidine

    International Nuclear Information System (INIS)

    Zecca, A; Chiari, L; Trainotti, E; GarcIa, G; Blanco, F; Brunger, M J

    2010-01-01

    In this paper we report original measurements of total cross sections for positron scattering from the important biomolecule pyrimidine. The energy range of these measurements was 0.3-45 eV, while the energy resolution was ∼260 meV. In addition, we report theoretical results, calculated within the independent atom-screened additivity rule (IAM-SCAR) formalism, for the corresponding electron impact total cross sections. In that case the energy range is 1-10 000 eV. Total cross sections are very important input data for codes that seek to simulate charged-particle tracks in matter, as they define the mean-free path between collisions. As the present data and computations are to the best of our knowledge the first total cross sections to be reported for either positron or electron scattering from pyrimidine, they fill an important void in our available knowledge in the literature.

  19. Triply differential cross sections for ionization of helium by electrons

    International Nuclear Information System (INIS)

    Brauner, M.; Briggs, J.S.; Broad, J.T.

    1991-01-01

    A correlated three-body continuum wavefunction, already successfully employed to describe hydrogen atom impact ionization, is used to calculate the triply-differential cross section for electron impact ionization of helium. A good description is obtained of all the major structure in the differential cross sections in both symmetric and asymmetric geometries. It is demonstrated how interference between the various projectile-target interactions is necessary to reproduce the experimentally observed structure. (author)

  20. Measurements of the electron and muon inclusive cross-sections

    Indian Academy of Sciences (India)

    We present the measurements of the differential cross-sections for inclusive electron and muon production in proton–proton collisions at a centre-of-mass energy of s = 7 TeV, using ∼ 1.4 pb-1 of data collected by the ATLAS detector at the Large Hadron Collider. The muon cross-section is measured as a function of muon ...

  1. Total cross sections for electron scattering by He

    International Nuclear Information System (INIS)

    De Heer, F.J.; Jansen, R.H.J.

    1977-01-01

    A set of total cross sections for scattering of electrons by He has been evaluated over the energy range of zero to 3000 eV by means of the analysis of experiments and theories on total cross sections for elastic scattering, ionisation and excitation, and on differential cross sections for elastic and inelastic scattering. Between 0 and 19.8 eV, where no inelastic processes occur, the total cross sections for scattering are equal to those for elastic scattering. Above 19.8 eV total cross sections for scattering of electrons have been evaluated by adding those for ionisation, excitation and elastic scattering. The total cross sections thus obtained are probably accurate to about 5% over a large part of the energy range. They appear to be in very good agreement with the recent experimental results of Blaauw et al. (J. Phys. B.; 10:L299 (1977)). The present results have already proved useful for application in the dispersion relation for forward scattering in electron-helium collisions. (author)

  2. Calculated Cross Sections for the Electron Impact Ionization of Molecular Ions

    Science.gov (United States)

    Deutsch, H.; Becker, K.; Defrance, P.; Onthong, U.; Parajuli, R.; Probst, M.; Matt-Leubner, S.; Maerk, T.

    2002-10-01

    We report the results of the application of the semi- classical Deutsch-Märk (DM) formalism to the calculation of the absolute electron-impact ionization cross section of the molecular ions H2+, N2+, O2+, CD+, CO+, CO2+, H3O+, and CH4+ for which experimental data have been reported . Where available, we also compare our calculated cross sections with calculated cross sections using the BEB method of Kim and co-workers. The level of agreement between the experimentally determined and calculated cross section is satisfactory in some cases. In all cases, the calculated cross sections exceed the measured cross sections which is not surprising in view of the experimental complications in measuring ionization cross sections of molecular ions due to the presence of competing channels such as ionization dissociative ionization, and dissociative excitation. Work supported in part by FWF, OEAW, and NASA.

  3. Communication: Electronic flux induced by crossing the transition state

    Science.gov (United States)

    Jia, Dongming; Manz, Jörn; Yang, Yonggang

    2018-01-01

    We present a new effect of chemical reactions, e.g., isomerizations, that occurs when the reactants pass along the transition state, on the way to products. It is based on the well-known fact that at the transition state, the electronic structure of one isomer changes to the other. We discover that this switch of electronic structure causes a strong electronic flux that is well distinguishable from the usual flux of electrons that travel with the nuclei. As a simple but clear example, the effect is demonstrated here for bond length isomerization of Na2 (21Σu+), with adiabatic crossing the barrier between the inner and outer wells of the double minimum potential that support different "Rydberg" and "ionic" type electronic structures, respectively.

  4. Electron collision cross sections and transport parameters in Cl2

    International Nuclear Information System (INIS)

    Pinhao, N.; Chouki, A.

    1995-01-01

    Molecular chlorine, Cl 2 , is a widely used gas with important application in gas discharge physics, namely in plasma etching, UV lasers and gas-filled particle detectors. However, due to experimental difficulties and to a complicated electronic spectrum, only some of the electron collision cross section have been measured and only recently the electronic structure has been resolved. This situation hampered the theoretical analysis of chlorine mixtures by a lack of relevant transport parameters. To our best knowledge there is only one published measurement of electron drift velocity and characteristic energy. Regrettably these data are considered of doubtful quality. There is also only one measurement of attachment and ionisation coefficients and one published set of cross sections. However those authors used the transport data from a He-Cl 2 mixture (80/20) where chlorine's effect can be hidden by the other component. Consequently that set is not completely consistent with the measurements in pure chlorine. This paper presents a new proposal of a consistent set of electron collision cross sections and the corresponding transport parameters and collision frequencies

  5. Near threshold electron impact ionization cross section for tellurium atoms

    International Nuclear Information System (INIS)

    Chipev, F.F.; Chernyshova, I.V.; Kontros, J.E.; Shpenik, O.B.

    2004-01-01

    Full text: Up today electron-impact ionization is one of the most intensively investigated processes in atomic and molecular physics [1]. These experiments however, are associated with difficulties: high temperatures and densities are required to produce atomic beams and monochromatic intensive electron beams. A crossed electron and atomic beams scattering geometry was employed to measure the ionization efficiency curve for tellurium atoms. Our electron spectrometer comprises two serially mounted hypocycloidal electron energy analyzers [2], the first being the monochromator and the second - the scattered electron analyzer. The whole spectrometer is immersed into the homogenous magnetic field. Great care was taken in selecting the value of the extracting potential at the electrode, mounted normally to the atomic beam direction. By careful choosing this potential as low as possible (∼1.4 V), its influence on the motion of the monochromatized electrons in the collision region was minimized and the full collection of the formed ions was reached. The atom beam was produced using a compact effusion source made of the stainless steel with a microchannel exit to minimise the angular divergency of the beam. The temperature of the microchannel plate was taken about 50 K higher than that of the metal vapour in the heated reservoir. This atomic beam source enabled to produce an atomic beam with the concentration of two orders of magnitude higher than that in the case of a standard effusion source. A typical value of the electron energy spread was 0.15 eV (FWHM) in the 0.1-15 eV energy range. The primary electron beam current was equal to 10 -7 A. Such values of electron energy spread and beam current for the primary electron beam passing through the collision chamber were chosen to provide identical conditions for carrying out all the measurements. The energy scale was calibrated with the accuracy of ± 0.05 eV. The measured ionization cross-section normalized to the results

  6. Analysis of Data on the Cross Sections for Electron-Impact Ionization and Excitation of Electronic States of Atomic Hydrogen (Review)

    Science.gov (United States)

    Shakhatov, V. A.; Lebedev, Yu. A.

    2018-01-01

    A review is given of experimental and theoretical data on the cross sections for ionization, excitation, and deexcitation of atomic hydrogen. The set of the cross sections required to calculate the electron energy distribution function and find the level-to-level rate coefficients needed to solve balance equations for the densities of neutral and charged particles in hydrogen plasma is determined.

  7. Theory for cross effect dynamic nuclear polarization under magic-angle spinning in solid state nuclear magnetic resonance: the importance of level crossings.

    Science.gov (United States)

    Thurber, Kent R; Tycko, Robert

    2012-08-28

    We present theoretical calculations of dynamic nuclear polarization (DNP) due to the cross effect in nuclear magnetic resonance under magic-angle spinning (MAS). Using a three-spin model (two electrons and one nucleus), cross effect DNP with MAS for electron spins with a large g-anisotropy can be seen as a series of spin transitions at avoided crossings of the energy levels, with varying degrees of adiabaticity. If the electron spin-lattice relaxation time T(1e) is large relative to the MAS rotation period, the cross effect can happen as two separate events: (i) partial saturation of one electron spin by the applied microwaves as one electron spin resonance (ESR) frequency crosses the microwave frequency and (ii) flip of all three spins, when the difference of the two ESR frequencies crosses the nuclear frequency, which transfers polarization to the nuclear spin if the two electron spins have different polarizations. In addition, adiabatic level crossings at which the two ESR frequencies become equal serve to maintain non-uniform saturation across the ESR line. We present analytical results based on the Landau-Zener theory of adiabatic transitions, as well as numerical quantum mechanical calculations for the evolution of the time-dependent three-spin system. These calculations provide insight into the dependence of cross effect DNP on various experimental parameters, including MAS frequency, microwave field strength, spin relaxation rates, hyperfine and electron-electron dipole coupling strengths, and the nature of the biradical dopants.

  8. Electron capture cross-section of Au-Fe complex in silicon

    International Nuclear Information System (INIS)

    Ali, Akbar; Shafi, M; Majid, Abdul

    2006-01-01

    A deep level transient spectroscopy technique is applied to study the capture cross-section of an iron-gold complex. The thermal ionization energy obtained from emission rate data is found to be E c -0.36 eV. The Au-Fe complex is a single defect having a capture cross-section of 2.48x10 -16 cm 2 for electrons which is independent of temperature

  9. Electron capture cross-section of Au-Fe complex in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Akbar; Shafi, M; Majid, Abdul [Advance Materials Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan)

    2006-10-15

    A deep level transient spectroscopy technique is applied to study the capture cross-section of an iron-gold complex. The thermal ionization energy obtained from emission rate data is found to be E{sub c} -0.36 eV. The Au-Fe complex is a single defect having a capture cross-section of 2.48x10{sup -16} cm{sup 2} for electrons which is independent of temperature.

  10. Non-statistically populated autoionizing levels of Li-like carbon: Hidden-crossings

    International Nuclear Information System (INIS)

    Deveney, E.F.; Krause, H.F.; Jones, N.L.

    1995-01-01

    The intensities of the Auger-electron lines from autoionizing (AI) states of Li-like (1s2s2l) configurations excited in ion-atom collisions vary as functions of the collision parameters such as, for example, the collision velocity. A statistical population of the three-electron levels is at best incomplete and underscores the intricate dynamical development of the electronic states. The authors compare several experimental studies to calculations using ''hidden-crossing'' techniques to explore some of the details of these Auger-electron intensity variation phenomena. The investigations show promising results suggesting that Auger-electron intensity variations can be used to probe collision dynamics

  11. Electron-impact ionization cross section of rubidium

    International Nuclear Information System (INIS)

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

    1998-01-01

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

  12. Luminosity Anti-leveling with Crossing Angle (MD 1669)

    CERN Document Server

    Gorzawski, Arkadiusz; Ponce, Laurette; Salvachua Ferrando, Belen Maria; Wenninger, Jorg; CERN. Geneva. ATS Department

    2016-01-01

    A significant fraction of the LHC luminosity ($\\sim$30\\% in 2016) is lost due to the presence (and necessity) of the crossing angles at the IPs. At the LHC the crossing angle is typically set to a value that provides sufficient separation of the beams at the start of fills for the peak bunch intensities. As the bunch intensity decays during a fill, it is possible to reduce the crossing angle and recover some luminosity. A smooth crossing angle reduction procedure must be developed to take advantage of this option during stable beam operation. During this MD a smooth procedure for luminosity leveling with crossing angle was tested. It was demonstrated that the orbit was well controlled, beam losses were low and the offset leveled experiments ALICE and LHCb were not affected by crossing angle leveling in ATLAS and CMS.

  13. On analytical fits for electron impact ionisation cross sections

    International Nuclear Information System (INIS)

    Godunov, A.L.; Ivanov, P.B.

    1999-01-01

    The problem of providing accurate recommended analytical fits for electron impact ionisation cross sections is discussed, and a number of approaches are considered on the sample case of neon and its ions. The previously known fits are being reassessed using complete experimental and theoretical data, with the preference for experiment, to avoid systematic shifts introduced by the present calculation methods. The feasibility of the standard BELI formula is investigated in detail, and a number of other analytical expressions is suggested, approximating single-ionization cross sections in the whole range of energies. The factors influencing the accuracy of the fits and the physical meaning of the parameters obtained are discussed. (orig.)

  14. Electron transport in silicon nanowires having different cross-sections

    Directory of Open Access Journals (Sweden)

    Muscato Orazio

    2016-06-01

    Full Text Available Transport phenomena in silicon nanowires with different cross-section are investigated using an Extended Hydrodynamic model, coupled to the Schrödinger-Poisson system. The model has been formulated by closing the moment system derived from the Boltzmann equation on the basis of the maximum entropy principle of Extended Thermodynamics, obtaining explicit closure relations for the high-order fluxes and the production terms. Scattering of electrons with acoustic and non polar optical phonons have been taken into account. The bulk mobility is evaluated for square and equilateral triangle cross-sections of the wire.

  15. Mean level signal crossing rate for an arbitrary stochastic process

    DEFF Research Database (Denmark)

    Yura, Harold T.; Hanson, Steen Grüner

    2010-01-01

    The issue of the mean signal level crossing rate for various probability density functions with primary relevance for optics is discussed based on a new analytical method. This method relies on a unique transformation that transforms the probability distribution under investigation into a normal...... probability distribution, for which the distribution of mean level crossings is known. In general, the analytical results for the mean level crossing rate are supported and confirmed by numerical simulations. In particular, we illustrate the present method by presenting analytic expressions for the mean level...

  16. Cross-sectional transmission electron microscopy of semiconductors

    International Nuclear Information System (INIS)

    Sadana, D.K.

    1982-10-01

    A method to prepare cross-sectional (X) semiconductor specimens for transmission electron microscopy (TEM) has been described. The power and utility of XTEM has been demonstrated. It has been shown that accuracy and interpretation of indirect structural-defects profiling techniques, namely, MeV He + channeling and secondary ion mass spectrometry (SIMS) can be greatly enhanced by comparing their results with those obtained by XTEM from the same set of samples

  17. Electron-impact-excitation cross sections of hydrogenlike ions

    International Nuclear Information System (INIS)

    Fisher, V.I.; Ralchenko, Y.V.; Bernshtam, V.A.; Goldgirsh, A.; Maron, Y.; Vainshtein, L.A.; Bray, I.; Golten, H.

    1997-01-01

    Convergent close-coupling (CCC) and Coulomb-Born with exchange and normalization (CBE) methods are used to study electron-impact excitation of hydrogenlike ions. The nl→n ' l ' cross sections demonstrate (i) good agreement between the CCC and CBE results, (ii) a scaling over ion nuclear charge z, (iii) a domination of the dipole (l ' =l±1) contributions in total n→n ' cross sections, and (iv) significant effect of electron exchange in the energy range x n,n ' ). For ions with z>5 the n→n ' cross sections obtained in the CCC and CBE approximations agree with each other to better than 10% for any x. An accuracy of the cross sections scaling over z 4 depends on z: for z=6 endash 18 the scaling is accurate to better than 10% (quantitative analysis is done for n ' 4 scaling more significantly (at x about unity). The n→n ' cross sections are presented by a formula which fits our CCC and CBE results with an accuracy to better than 10% (for transitions with n ' 5). The new Gaunt factor G(x) suggested for the widely used Van Regemorter formula [Astrophys. J. 136, 906 (1962)] makes this formula accurate to better than 50% in the x>3 range and to better than 20% in the x>100 range. It is shown that the semiempirical formula by Vainshtein, Sobelman, and Yukov provides an accuracy to better than 50% for any incident electron energy. For x<2 this formula is accurate to better than 30%. These accuracy assessments are based on a comparison with our CCC and CBE results. copyright 1997 The American Physical Society

  18. Electron and positron atomic elastic scattering cross sections

    International Nuclear Information System (INIS)

    Stepanek, Jiri

    2003-01-01

    A method was developed to calculate the total and differential elastic-scattering cross sections for incident electrons and positrons in the energy range from 0.01 eV to 1 MeV for atoms of Z=1-100. For electrons, hydrogen, helium, nitrogen, oxygen, krypton, and xenon, and for positrons, helium, neon, and argon atoms were considered for comparison with experimental data. First, the variationally optimized atomic static potentials were calculated for each atom by solving the Dirac equations for bound electron states. Second, the Dirac equations for a free electron or positron are solved for an atom using the previously calculated static potential accomplished (in the case of electrons) by 'adjusted' Hara's exchange potential for a free-state particle. Additional to the exchange effects, the charge cloud polarization effects are considered applying the correlation-polarization potential of O'Connell and Lane (with correction of Padial and Norcross) for incident electrons, and of Jain for incident positrons. The total, cutoff and differential elastic-scattering cross sections are calculated for incident electrons and positrons with the help of the relativistic partial wave analysis. The solid state effects for scattering in solids are described by means of a muffin-tin model, i.e. the potentials of neighboring atoms are superpositioned in such a way that the resulting potential and its derivative are zero in the middle distance between the atoms. The potential of isolated atom is calculated up to the radius at which the long-range polarization potential becomes a value of -10 -8

  19. Electron microscopy at reduced levels of irradiation

    International Nuclear Information System (INIS)

    Kuo, I.A.M.

    1975-05-01

    Specimen damage by electron radiation is one of the factors that limits high resolution electron microscopy of biological specimens. A method was developed to record images of periodic objects at a reduced electron exposure in order to preserve high resolution structural detail. The resulting image would tend to be a statistically noisy one, as the electron exposure is reduced to lower and lower values. Reconstruction of a statistically defined image from such data is possible by spatial averaging of the electron signals from a large number of identical unit cells. (U.S.)

  20. Deconvolution of overlapping features in electron energy-loss spectra: the determination of absolute differential cross sections for electron-impact excitation of electronic states of molecules

    International Nuclear Information System (INIS)

    Campbell, L.; Brunger, M.J.; Teubner, O.J.P.; Mojarrabi, B.

    1996-06-01

    A set of three computer programs is reported which allow for the deconvolution of overlapping molecular electronic state structure in electron energy-loss spectra, even in highly perturbed systems. This procedure enables extraction of absolute differential cross sections for electron-impact excitation of electronic states of diatomic molecules from electron energy-loss spectra. The first code in the sequence uses the Rydberg-Klein-Rees procedure to generate potential energy curves from spectroscopic constants, while the second calculates Franck-Condon factors by numerical solution of the Schroedinger equation, given the potential energy curves. The third, given these Franck-Condon factors, the previously calculated relevant energies for the vibrational levels of the respective electronic states and the experimental energy-loss spectra, extracts the differential cross sections for each state. Each program can be run independently, or the three can run in sequence to determine these cross sections from the spectroscopic constants and the experimental energy-loss spectra. The application of these programs to the specific case of electron scattering from nitric oxide (NO) is demonstrated. 25 refs., 2 tabs., 2 figs

  1. Electron impact ionisation cross sections of iron oxides

    Science.gov (United States)

    Huber, Stefan E.; Mauracher, Andreas; Sukuba, Ivan; Urban, Jan; Maihom, Thana; Probst, Michael

    2017-12-01

    We report electron impact ionisation cross sections (EICSs) of iron oxide molecules, FexOx and FexOx+1 with x = 1, 2, 3, from the ionisation threshold to 10 keV, obtained with the Deutsch-Märk (DM) and binary-encounter-Bethe (BEB) methods. The maxima of the EICSs range from 3.10 to 9 . 96 × 10-16 cm2 located at 59-72 eV and 5.06 to 14.32 × 10-16 cm2 located at 85-108 eV for the DM and BEB approaches, respectively. The orbital and kinetic energies required for the BEB method are obtained by employing effective core potentials for the inner core electrons in the quantum chemical calculations. The BEB cross sections are 1.4-1.7 times larger than the DM cross sections which can be related to the decreasing population of the Fe 4s orbitals upon addition of oxygen atoms, together with the different methodological foundations of the two methods. Both the DM and BEB cross sections can be fitted excellently to a simple analytical expression used in modelling and simulation codes employed in the framework of nuclear fusion research. Supplementary material in the form of one pdf file available from the Journal web page at http://https://doi.org/10.1140/epjd/e2017-80308-2.

  2. Level crossing analysis of Burgers equation in 1 + 1 dimensions

    International Nuclear Information System (INIS)

    Movahed, M Sadegh; Bahraminasab, A; Rezazadeh, H; Masoudi, A A

    2006-01-01

    We investigate the average frequency of positive slope ν + α , crossing the velocity field u(x) - u-bar = α in the Burgers equation. The level crossing analysis in the inviscid limit and the total number of positive crossings of the velocity field before the creation of singularities are given. The main goal of this paper is to show that this quantity, ν + α , is a good measure for the fluctuations of velocity fields in the Burgers turbulence

  3. Electron ejection cross sections in electron and ion impact ionization: Ab initio and semiempirical calculations

    International Nuclear Information System (INIS)

    Manson, S.T.; Miller, J.H.; Pacific Northwest Lab., Richland, WA)

    1983-01-01

    Ionization cross sections for heavy ions and electrons incident on various atoms and molecules are required in the modeling of the interaction of radiation with matter. For each case, the energy distribution of secondary electrons (the single differential cross section, SDCS) is needed over a broad range of projectile and secondary electron (delta-ray) energies. In many cases the energy and angular distribution of secondary electrons (the double differential cross section, DDCS) is also necessary. Clearly, it would be desirable to have laboratory SDCS and DDCS measurements for all of the cases required. For a variety of reasons, this is not yet possible. Thus, one must turn elsewhere to obtain the needed cross sections. In this paper, we discuss cross sections obtained in two different ways; ab initio theory based on the first Born approximation, and a semi-empirical method based on the Bethe-Born Approximation. In both cases, results on helium will be presented since the largest amount of data is available in this case. Applications of both methods to other target species are given in the references. The accuracy of the methods and plans for the near future are also discussed. 23 references, 6 figures

  4. Secondary-electron-production cross sections for electron-impact ionization of helium

    International Nuclear Information System (INIS)

    Goruganthu, R.R.; Bonham, R.A.

    1986-01-01

    Measurements of the double-differential cross sections (DDCS) as a function of the ejected energy, angle, and primary energy for electron-impact ionization of helium are reported at incident energies of 200, 500, 1000, and 2000 eV. The ejection angle is varied from 30 0 to 150 0 in steps of 15 0 . The cross sections were obtained by use of a crossed-beam apparatus with an effusive gas source and a pulsed electron beam. Scattered and ejected electrons were energy analyzed by time-of-flight analysis from 2 eV to the primary energy as a function of the ejection angle. The relative measurements were normalized by matching the experimental elastic differential cross sections to absolute measurements at selected angles. Comparisons of the DDCS with available literature values revealed significant differences. At 2000 eV impact energy, first-Born-approximation calculations of the DDCS were found to be in agreement with the present data for ejected energies between 2 and 40 eV. At large angles and lower incident energies the Born calculation results are lower than the present DDCS. The DDCS were fitted with a Legendre-polynomial expansion as a function of ejection angle for fixed ejected and primary energies. The energy distributions of ejected electrons derived from these fits are presented and used to calculate the total ionization cross section

  5. Differential cross sections and cross-section ratios for the electron-impact excitation of the neon 2p53s configuration

    International Nuclear Information System (INIS)

    Khakoo, M. A.; Wrkich, J.; Larsen, M.; Kleiban, G.; Kanik, I.; Trajmar, S.; Brunger, M.J.; Teubner, P.J.O.; Crowe, A.; Fontes, C.J.; Clark, R.E.H.; Zeman, V.; Bartschat, K.; Madison, D.H.; Srivastava, R.; Stauffer, A.D.

    2002-01-01

    Electron-impact differential cross-section measurements for the excitation of the 2p 5 3s configuration of Ne are reported. The Ne cross sections are obtained using experimental differential cross sections for the electron-impact excitation of the n=2 levels of atomic hydrogen [Khakoo et al., Phys. Rev. A 61, 012701-1 (1999)], and existing experimental helium differential cross-section measurements, as calibration standards. These calibration measurements were made using the method of gas mixtures (Ne and H followed by Ne and He), in which the gas beam profiles of the mixed gases are found to be the same within our experimental errors. We also present results from calculations of these differential cross sections using the R-matrix and unitarized first-order many-body theory, the distorted-wave Born approximation, and relativistic distorted-wave methods. Comparison with available experimental differential cross sections and differential cross-section ratios is also presented

  6. Relating measurement invariance, cross-level invariance, and multilevel reliability

    OpenAIRE

    Jak, S.; Jorgensen, T.D.

    2017-01-01

    Data often have a nested, multilevel structure, for example when data are collected from children in classrooms. This kind of data complicate the evaluation of reliability and measurement invariance, because several properties can be evaluated at both the individual level and the cluster level, as well as across levels. For example, cross-level invariance implies equal factor loadings across levels, which is needed to give latent variables at the two levels a similar interpretation. Reliabili...

  7. Higher energy dissociative electron attachment cross sections in sulfur dioxide

    International Nuclear Information System (INIS)

    Kurepa, M.; Pejcev, V.; Cadez, I.

    2000-01-01

    Experimental results of total electron attachment cross sections are presented with, for comparison, two additional sets of data, those of Orient and Srivastava and of Spyrou et al.. Both were normalized to present values of the first attachment peak at 4,6 eV, in order to show more clearly differences in cross section curve shapes. In fact, data of Orient and Srivastava are larger that the present ones for a factor of 2,82; while those of Spyrou et al. are higher only for 3,70 %. Both these sets of data, as well as those by Cadez et al., cover an incident electron energy range 3,40 - 9,40 eV. Electron attachment processes at energies higher that 9,40 eV have been in fact detected and measured in the same set of experiments that led to former publication of lower energy attachment processes by Cadez et al.. At that time in none of experiments, that could distinguished ionic species formed in dissociation attachment processes, was a sign of ions at incident electron energies exceeding 9,40 eV. That caused our ignorance toward processes detected and measured at higher incident electron energies, mainly since they were at least one order of magnitude lower that the two peaks at 4,6 eV and 7,3 eV, respectively. Without additional experiments, that include mass analysis of ionic species formed in dissociative electron attachment processes, it is not possible to give any sound explanation to causes of peaks at energies higher that 8,0 eV

  8. Exact analytic solutions for Mikheyev-Smirnov-Wolfenstein level crossings

    International Nuclear Information System (INIS)

    Noetzold, D.

    1987-01-01

    An exact formula for the transition probability in level-crossing phenomena is derived for a general case, ranging from adiabatic to sudden crossings. This is done in the context of neutrino flavor oscillations for the Mikheyev-Smirnov-Wolfenstein (MSW) effect, where hitherto only numerical or approximate solutions were obtained. The matter density or level splitting is assumed to be governed by a hyperbolic-tangent function which, however, can change arbitrarily fast between two constant values. For example, in context of the MSW effect this furnishes a nice fit to the solar density determining the level crossing of solar neutrinos. In the quasiadiabatic limit the exact Landau-Zener factor can be read off, correcting some expressions obtained so far. Even in the opposite limit of a sudden level crossing a conversion is found, which can have far-reaching consequences for neutrino detection on Earth

  9. Electron-impact excitation and ionization cross sections for ground state and excited helium atoms

    International Nuclear Information System (INIS)

    Ralchenko, Yu.; Janev, R.K.; Kato, T.; Fursa, D.V.; Bray, I.; Heer, F.J. de

    2008-01-01

    Comprehensive and critically assessed cross sections for the electron-impact excitation and ionization of ground state and excited helium atoms are presented. All states (atomic terms) with n≤4 are treated individually, while the states with n≥5 are considered degenerate. For the processes involving transitions to and from n≥5 levels, suitable cross section scaling relations are presented. For a large number of transitions, from both ground and excited states, convergent close coupling calculations were performed to achieve a high accuracy of the data. The evaluated/recommended cross section data are presented by analytic fit functions, which preserve the correct asymptotic behavior of the cross sections. The cross sections are also displayed in graphical form

  10. A dissociative electron attachment cross-section estimator

    International Nuclear Information System (INIS)

    Munro, James J; Harrison, Stephen; Fujimoto, Milton M; Tennyson, Jonathan

    2012-01-01

    Dissociative electron attachment (DEA) is the major process where molecules are destroyed in low-energy plasmas. DEA cross sections are therefore important for a whole variety of applications but are both hard to measure or compute accurately. A method for estimating DEA cross sections based a simple resonance plus survival model is presented. Test results are presented for DEA of molecular oxygen and molecular chlorine, for which experimental measurements are available for comparison, and SiBr and SiBr 2 , for which no previous data is available. The estimator has been implemented as part of Quantemol-N expert system which uses the R-matrix method to predict resonance positions and widths.

  11. Total cross sections for electron scattering with halocarbon molecules

    Energy Technology Data Exchange (ETDEWEB)

    Naghma, Rahla; Gupta, Dhanoj; Antony, Bobby, E-mail: bka.ism@gmail.com

    2014-03-01

    Highlights: • A quantum mechanical model to find elastic, inelastic and total CS by e{sup −} impact. • Spherical complex optical potential formalism is used to find total CS. • Result shows consistency and good agreement with previous data wherever available. • Maiden attempt to find CS for CH{sub 2}Br{sub 2}, CHBr{sub 3}, CBr{sub 4} and C{sub n}H{sub 2n+1}Cl (n = 2–4) molecules. • Interesting correlation observed between total CS and polarizability of the molecule. - Abstract: A theoretical study on electron collision with chlorinated methanes: CH{sub 2}Cl{sub 2} and CHCl{sub 3}, brominated methanes: CH{sub 2}Br{sub 2}, CHBr{sub 3} and CBr{sub 4} and some mono chloroalkanes: C{sub n}H{sub 2n+1}Cl (n = 2–4) molecules in gaseous ground state is undertaken to report elastic, inelastic and total cross sections in the 20–5000 eV energy range. The target molecule is represented as a sum of various scattering centres, which are assumed to scatter electrons independently. The spherical complex optical potential (SCOP) is formulated to represent the interaction dynamics between the electron and the constituent scattering centres. Using SCOP, the quantum mechanical scattering problem is solved through partial wave analysis. The results obtained for CH{sub 2}Cl{sub 2} and CHCl{sub 3} are compared with the available experimental and theoretical values. The elastic cross section for CBr{sub 4} shows satisfactory agreement with the previous available data. The cross sections for CH{sub 2}Br{sub 2}, CHBr{sub 3}, and C{sub n}H{sub 2n+1}Cl (n = 2–4) molecules presented in this work are reported for the first time.

  12. Two-electron photoionization cross sections at high energies

    International Nuclear Information System (INIS)

    Amusia, M.Ya.; Krivec, R.; Mandelzweig, V.B.

    2003-01-01

    Double and single electron photoionization cross sections and their ratios at high and ultra-relativistic energies are calculated for H - , He and helium-like ions in ground and excited states including triplet states. The ratios contain shake-off and quasi-free terms. A high precision non-variational wave function is used. The quasi-free mechanism increases the ratios impressively: for He we get 0.0762 instead of 0.0164 in the non-relativistic case. Ratios are inversely proportional to Z 2 , with a factor increasing from 0.094 in the nonrelativistic to 0.595 in the ultra-relativistic limit. (author)

  13. Empirical Fit to Inelastic Electron-Deuteron and Electron-Neutron Resonance Region Transverse Cross Sections

    International Nuclear Information System (INIS)

    Peter Bosted; M. E. Christy

    2007-01-01

    An empirical fit is described to measurements of inclusive inelastic electron-deuteron cross sections in the kinematic range of four-momentum transfer 0 (le) Q 2 2 and final state invariant mass 1.2 p of longitudinal to transverse cross sections for the proton, and the assumption R p =R n . The underlying fit parameters describe the average cross section for proton and neutron, with a plane-wave impulse approximation (PWIA) used to fit to the deuteron data. Pseudo-data from MAID 2007 were used to constrain the average nucleon cross sections for W<1.2 GeV. The mean deviation of data from the fit is 3%, with less than 5% of the data points deviating from the fit by more than 10%

  14. Electrically controlled crossing of energy levels in quantum dots in two-dimensional topological insulators

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, Aleksei A.

    2017-05-15

    We study the energy spectra of bound states in quantum dots (QDs) formed by an electrostatic potential in two-dimensional topological insulator (TI) and their transformation with changes in QD depth and radius. It is found that, unlike a trivial insulator, the energy difference between the levels of the ground state and first excited state can decrease with decreasing the radius and increasing the depth of the QD so that these levels intersect under some critical condition. The crossing of the levels results in unusual features of optical properties caused by intraceneter electron transitions. In particular, it leads to significant changes of light absorption due to electron transitions between such levels and to the transient electroluminescence induced by electrical tuning of QD and TI parameters. In the case of magnetic TIs, the polarization direction of the absorbed or emitted circularly polarized light is changed due to the level crossing.

  15. Electrically controlled crossing of energy levels in quantum dots in two-dimensional topological insulators

    Science.gov (United States)

    Sukhanov, Aleksei A.

    2017-05-01

    We study the energy spectra of bound states in quantum dots (QDs) formed by an electrostatic potential in two-dimensional topological insulator (TI) and their transformation with changes in QD depth and radius. It is found that, unlike a trivial insulator, the energy difference between the levels of the ground state and first excited state can decrease with decreasing the radius and increasing the depth of the QD so that these levels intersect under some critical condition. The crossing of the levels results in unusual features of optical properties caused by intraceneter electron transitions. In particular, it leads to significant changes of light absorption due to electron transitions between such levels and to the transient electroluminescence induced by electrical tuning of QD and TI parameters. In the case of magnetic TIs, the polarization direction of the absorbed or emitted circularly polarized light is changed due to the level crossing.

  16. Excitation of the 5p57p levels of xenon by electron impact

    International Nuclear Information System (INIS)

    Sharma, L.; Sharma, L.; Srivastava, R.; Stauffer, A.D.

    2011-01-01

    We have used our relativistic distorted-wave method to calculate cross sections for the electron-impact excitation of the ground state of xenon to all the 5p 5 7p fine-structure levels. The results are compared with the recent experimental measurements of Jung et al. [Phys. Rev. A 80, 062708 (2009)]. We show that the measured cross sections of Jung et al. for excitation of the levels with angular momentum J odd are dominated by cascading from higher-lying levels. Analytic fits to our cross sections are also provided for use in plasma modeling studies

  17. Electronic circuit provides automatic level control for liquid nitrogen traps

    Science.gov (United States)

    Turvy, R. R.

    1968-01-01

    Electronic circuit, based on the principle of increased thermistor resistance corresponding to decreases in temperature provides an automatic level control for liquid nitrogen cold traps. The electronically controlled apparatus is practically service-free, requiring only occasional reliability checks.

  18. Pixel detector readout electronics with two-level discriminator scheme

    International Nuclear Information System (INIS)

    Pengg, F.

    1998-01-01

    In preparation for a silicon pixel detector with more than 3,000 readout channels per chip for operation at the future large hadron collider (LHC) at CERN the analog front end of the readout electronics has been designed and measured on several test-arrays with 16 by 4 cells. They are implemented in the HP 0.8 microm process but compatible with the design rules of the radiation hard Honeywell 0.8 microm bulk process. Each cell contains bump bonding pad, preamplifier, discriminator and control logic for masking and testing within a layout area of only 50 microm by 140 microm. A new two-level discriminator scheme has been implemented to cope with the problems of time-walk and interpixel cross-coupling. The measured gain of the preamplifier is 900 mV for a minimum ionizing particle (MIP, about 24,000 e - for a 300 microm thick Si-detector) with a return to baseline within 750 ns for a 1 MIP input signal. The full readout chain (without detector) shows an equivalent noise charge to 60e - r.m.s. The time-walk, a function of the separation between the two threshold levels, is measured to be 22 ns at a separation of 1,500 e - , which is adequate for the 40 MHz beam-crossing frequency at the LHC. The interpixel cross-coupling, measured with a 40fF coupling capacitance, is less than 3%. A single cell consumes 35 microW at 3.5 V supply voltage

  19. Electron impact ionisation cross-sections of 2-heptanone

    Science.gov (United States)

    Vacher, J. R.; Blin-Simiand, N.; Jorand, F.; Pasquiers, S.

    2005-01-01

    The electron impact ionisation of 2-heptanone between 13 and 78 eV is studied using mass spectrometry. CH3C(O)CH2CH2CH2CH2CH3+ and fragment ions are produced with a total cross-section of 5 × 10-16 cm2 towards 50 eV. Two ions, identified as CH3CO+ (43 amu) and CH3C(OH)CH2+ (58 amu), contribute to about 60% of the total cross-section for electron energies above the ionisation threshold. The detected ions are identified using ab initio calculations. For E = 14 eV, the ion of 58 amu is the most abundant followed by an ion of 59 amu identified as being CH3C(OH)CH3+; they result from a bond cleavage with one or two H atom rearrangements. For E >= 48 eV, the ion of 43 amu is the most abundant; it results from an [alpha]-cleavage reaction in the molecular ion.

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  1. Inversion of the total cross sections for electron-molecule and electron-atom scattering

    International Nuclear Information System (INIS)

    Lun, D.R.; Amos, K.; Allen, L.J.

    1994-01-01

    Inverse scattering theory has been applied to construct the interaction potentials from total cross sections as a function of energy for electrons scattered off of atoms and molecules. The underlying potentials are assumed to be real and energy independent and are evaluated using the Eikonal approximation and with real phase shifts determined from the total cross sections. The inversion potentials have been determined using either a high energy limit approximation or by using a fixed energy inversion method at select energies. These procedures have been used to analyse e - - CH 4 , e - - SiH 4 , e - -Kr and e - -Xe scattering data in particular. 14 refs., 1 tabs., 3 figs

  2. Cross sections for electron-impact excitation of argon by fourier transform spectroscopy

    International Nuclear Information System (INIS)

    Chilton, J.E.; Boffard, J.B.; Chun C.L.

    1996-01-01

    The authors report absolute measurements of electron-impact excitation cross sections out of the ground level to the ten levels in the 3p 5 4p configuration of argon. The apparent excitation cross sections are determined by measuring the optical cross sections for the emission lines in the 3p 5 4p → 3p 5 4s manifold. For cascade corrections the authors measured the optical cross sections for the various 3p 5 5s → 3p 5 4p and 3p 5 4p infrared lines using a Fourier transform weak emission spectrometer to obtain the direct excitation cross sections from the optical data. Although the optical cross sections vary with pressure in the regime of 0.1 to 6 mTorr, the direct cross sections remain invariant. These pressure effects are understood within the framework of a radiation-reabsorption model. The excitation functions for the different transitions are also found to show considerable variation in shape

  3. Intermediate energy cross sections for electron-impact vibrational-excitation of pyrimidine

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Ellis-Gibbings, L.; García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); Nixon, K. L. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); School of Biology, Chemistry and Forensic Science, University of Wolverhampton, Wolverhampton WV1 1LY (United Kingdom); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-09-07

    We report differential cross sections (DCSs) and integral cross sections (ICSs) for electron-impact vibrational-excitation of pyrimidine, at incident electron energies in the range 15–50 eV. The scattered electron angular range for the DCS measurements was 15°–90°. The measurements at the DCS-level are the first to be reported for vibrational-excitation in pyrimidine via electron impact, while for the ICS we extend the results from the only previous condensed-phase study [P. L. Levesque, M. Michaud, and L. Sanche, J. Chem. Phys. 122, 094701 (2005)], for electron energies ⩽12 eV, to higher energies. Interestingly, the trend in the magnitude of the lower energy condensed-phase ICSs is much smaller when compared to the corresponding gas phase results. As there is no evidence for the existence of any shape-resonances, in the available pyrimidine total cross sections [Baek et al., Phys. Rev. A 88, 032702 (2013); Fuss et al., ibid. 88, 042702 (2013)], between 10 and 20 eV, this mismatch in absolute magnitude between the condensed-phase and gas-phase ICSs might be indicative for collective-behaviour effects in the condensed-phase results.

  4. Carboxymethyl starch cross-linked by electron beam radiation in presence of acrylic acid sensitizer

    International Nuclear Information System (INIS)

    Doan Binh; Nguyen Thanh Duoc; Pham Thi Thu Hong

    2013-01-01

    Carboxymethyl starch (CMS) can be cross-linked by electron beam radiation to form a biocompatible and environment-friendly hydrogel at a high absorbed dose and a condensed CMS concentration. Acrylic acid (AAc) can be used as a sensitizer in order to reduce the absorbed doses to an acceptable certain level. At an absorbed dose of 3-4 kGy, the gel content of crosslinked CMS can be obtained about 50% with 5% (w/w) AAc concentration used. The compressive strength of CMS samples increased with increasing their cross-linked densities due to raising absorbed doses. The swelling ratio of cross-linked CMS was also attainable at a maximum of 50 times in the distilled water. The enzymatic degradation of cross-linked CMS was carried out in acetate buffer pH 4.6 with 0.1% α-amylase enzymatic solution incubated at 40℃ for 6 h. The crosslinked CMS samples were degraded slower than uncrosslinked CMS ones. The results indicated that the highly cross-linked CMS was almost fully degradable when the enzymatic hydrolysis was performed during 6 h. The FT IR spectra of cross-linked CMS in the presence of AAc were examined to observe the carboxyl group of AAc in the structure of cross-linked CMS. The hydrophilic of cross-linked CMS surface was determined by a contact-angle analysis. (authors)

  5. Evolution of superpositions of quantum states through a level crossing

    International Nuclear Information System (INIS)

    Torosov, B. T.; Vitanov, N. V.

    2011-01-01

    The Landau-Zener-Stueckelberg-Majorana (LZSM) model is widely used for estimating transition probabilities in the presence of crossing energy levels in quantum physics. This model, however, makes the unphysical assumption of an infinitely long constant interaction, which introduces a divergent phase in the propagator. This divergence remains hidden when estimating output probabilities for a single input state insofar as the divergent phase cancels out. In this paper we show that, because of this divergent phase, the LZSM model is inadequate to describe the evolution of pure or mixed superposition states across a level crossing. The LZSM model can be used only if the system is initially in a single state or in a completely mixed superposition state. To this end, we show that the more realistic Demkov-Kunike model, which assumes a hyperbolic-tangent level crossing and a hyperbolic-secant interaction envelope, is free of divergences and is a much more adequate tool for describing the evolution through a level crossing for an arbitrary input state. For multiple crossing energies which are reducible to one or more effective two-state systems (e.g., by the Majorana and Morris-Shore decompositions), similar conclusions apply: the LZSM model does not produce definite values of the populations and the coherences, and one should use the Demkov-Kunike model instead.

  6. Strong overtones modes in inelastic electron tunneling spectroscopy with cross-conjugated molecules

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo; Gagliardi, Alessio; Pecchia, Alessandro

    2013-01-01

    . With this in mind, we investigate a spectroscopic method capable of providing insight into these junctions for cross-conjugated molecules: inelastic electron tunneling spectroscopy (IETS). IETS has the advantage that the molecule interface is probed directly by the tunneling current. Previously, it has been thought...... and leading to suppressed levels of elastic current. In most theoretical studies, only the elastic contributions to the current are taken into account. In this paper, we study the inelastic contributions to the current in cross-conjugated molecules and find that while the inelastic contribution to the current...

  7. A critical comparison of electron scattering cross sections measured by single collision and swarm techniques

    International Nuclear Information System (INIS)

    Buckman, S.J.; Brunger, M.J.

    1996-07-01

    Electron scattering cross sections (elastic, rotational and vibrational excitation) for a number of atomic and (relatively) single molecular systems are examined. Particular reference is made to the level of agreement which is obtained from the application of the completely different measurement philosophies embodied in 'beam' and 'swarm' techniques. The range of energies considered is generally restricted to the region below 5 eV. 142 refs., 1 tab., 12 figs

  8. Level crossing in a molecular Cr8 ring

    International Nuclear Information System (INIS)

    Affronte, M.; Guidi, T.; Caciuffo, R.; Carretta, S.; Amoretti, G.; Hinderer, J.; Sheikin, I.; Smith, A.A.; Winpenny, R.E.P.; Slageren, J. van; Gatteschi, D.

    2004-01-01

    The heat capacity of a molecular Cr 8 ring was measured as a function of temperature and magnetic field in order to follow the evolution of the Schottky anomaly through the first (S=0 to |1,-1>) level crossing occurring at B c1 =6.9 T. The results are interpreted within the framework of a spin Hamiltonian approach and they nicely fit the pattern of the energy levels derived by inelastic neutron spectroscopy. At B c1 , the Schottky anomaly almost vanishes suggesting that a true crossing occurs in Cr 8 in contrast to what was observed for ferric wheels

  9. Level crossing in a molecular Cr{sub 8} ring

    Energy Technology Data Exchange (ETDEWEB)

    Affronte, M. E-mail: affronte@unimore.it; Guidi, T.; Caciuffo, R.; Carretta, S.; Amoretti, G.; Hinderer, J.; Sheikin, I.; Smith, A.A.; Winpenny, R.E.P.; Slageren, J. van; Gatteschi, D

    2004-05-01

    The heat capacity of a molecular Cr{sub 8} ring was measured as a function of temperature and magnetic field in order to follow the evolution of the Schottky anomaly through the first (S=0 to |1,-1>) level crossing occurring at B{sub c1}=6.9 T. The results are interpreted within the framework of a spin Hamiltonian approach and they nicely fit the pattern of the energy levels derived by inelastic neutron spectroscopy. At B{sub c1}, the Schottky anomaly almost vanishes suggesting that a true crossing occurs in Cr{sub 8} in contrast to what was observed for ferric wheels.

  10. Secondary-electron-production cross sections for electron-impact ionization of molecular nitrogen

    International Nuclear Information System (INIS)

    Goruganthu, R.R.; Wilson, W.G.; Bonham, R.A.

    1987-01-01

    Measurements of the double-differential cross section (DDCS), as a function of the ejected energy, angle, and primary energy for electron-impact ionization of molecular nitrogen are reported at incident energies of 200, 500, 1000, and 2000 eV. The ejection angle was varied from 30 0 to 150 0 in steps of 15 0 . The cross sections were obtained by use of a crossed-beam apparatus with an effusive gas source and a pulsed electron beam. Scattered and ejected electrons were energy analyzed by time-of-flight analysis from below 2 eV to the primary energy. The relative measurements were placed on an absolute scale by matching the experimental elastic differential cross sections to absolute measurements at each primary energy. Comparisons of the DDCS with previous reported values revealed significant differences. The DDCS were fitted to a Legendre polynomial expansion as a function of the ejection angle. Platzman plot analysis was carried out on the energy distributions determined from the fit coefficients. The total ionization cross sections at these primary energies were deduced from this plot. An autoionization feature at 2.3 eV was observed for the first time in measurements of this nature and has been assigned as due to a Rydberg state converging to the B 2 Σ/sub u/ + ionic state which decays to the X 2 Σ/sub g/ + ground state of N 2 + . An analysis of the autoionization lines observed in the present work in the range 0.4--2.5 eV is also presented

  11. Empirical fit to inelastic electron-deuteron and electron-neutron resonance region transverse cross sections

    International Nuclear Information System (INIS)

    Bosted, P. E.; Christy, M. E.

    2008-01-01

    An empirical fit is described to measurements of inclusive inelastic electron-deuteron cross sections in the kinematic range of four-momentum transfer 0≤Q 2 2 and final state invariant mass 1.1 p of longitudinal to transverse cross sections for the proton, and the assumption R p =R n . The underlying fit parameters describe the average cross section for a free proton and a free neutron, with a plane-wave impulse approximation used to fit to the deuteron data. Additional fit parameters are used to fill in the dip between the quasi-elastic peak and the Δ(1232) resonance. The mean deviation of data from the fit is 3%, with less than 4% of the data points deviating from the fit by more than 10%

  12. Level dynamics: An approach to the study of avoided level crossings and transition to chaos

    International Nuclear Information System (INIS)

    Wang, S.; Chu, S.Y.

    1993-01-01

    The Dyson-Pechukas level dynamics has been reformulated and made suitable for studying avoided level crossings and transition to chaos. The N-level dynamics is converted into a many-body problem of one-dimensional Coulomb gas with N-constituent particles having intrinsic excitations. It is shown that local fluctuation of the level distribution is generated by a large number of avoided level crossings. The role played by avoided level crossings in generating chaoticity in level dynamics is similar to the role played by short-range collisions in causing thermalization in many-body dynamics. Furthermore, the effect of level changing rates in producing avoided level crossings is the same as particle velocities in causing particle-particle collisions. A one-dimensional su(2) Hamiltonian has been constructed as an illustration of the level dynamics, showing how the avoided level crossings cause the transition from a regular distribution to the chaotic Gaussian orthogonal ensemble (GOE) distribution of the levels. The existence of the one-dimensional su(2) Hamiltonian which can show both GOE and Poisson level statistics is remarkable and deserves further investigation

  13. Electron-Impact Excitation Cross Sections for Modeling Non-Equilibrium Gas

    Science.gov (United States)

    Huo, Winifred M.; Liu, Yen; Panesi, Marco; Munafo, Alessandro; Wray, Alan; Carbon, Duane F.

    2015-01-01

    In order to provide a database for modeling hypersonic entry in a partially ionized gas under non-equilibrium, the electron-impact excitation cross sections of atoms have been calculated using perturbation theory. The energy levels covered in the calculation are retrieved from the level list in the HyperRad code. The downstream flow-field is determined by solving a set of continuity equations for each component. The individual structure of each energy level is included. These equations are then complemented by the Euler system of equations. Finally, the radiation field is modeled by solving the radiative transfer equation.

  14. Channeling of electrons in a crossed laser field

    Directory of Open Access Journals (Sweden)

    S. B. Dabagov

    2015-06-01

    Full Text Available In this article a new analytical description of the effective interaction potential for a charged particle with the field of two interfering laser beams is presented. The potential dependence on the lasers intensities, orientation and parameters of the particle entering the considered system is analyzed. For the first time the phenomenon of effective potential inversion (or “relativistic reversal” is described for arbitrary lasers crossing angle. Threshold electron velocity values for the phenomenon are introduced and its extended illustration based on numerical simulations for two laser beams polarizations is presented. In addition the projectile radiation spectral distribution is given and general estimations on the expected beam radiation yield are outlined.

  15. Electron-impact ionization doubly differential cross sections of helium

    International Nuclear Information System (INIS)

    Bray, Igor; Fursa, Dmitry V; Stelbovics, Andris T

    2003-01-01

    The convergent close-coupling (CCC) method is applied to the calculation of electron-helium ionization doubly differential cross sections (DDCSs) at low to intermediate incident energies. We re-examine the CCC calculations and measurements of Roeder et al (1997 J. Phys. B: At. Mol. Opt. Phys. 30 1309-22) by making allowance for the step-function behaviour of the underlying CCC-calculated amplitudes. As done previously, the experimental DDCS were normalized at energies below 100 eV using the 100 eV CCC calculation to determine analyser properties at several secondary energies. In addition, substantially larger calculations are presented, to check the convergence. The agreement between the experiment and the calculations as a whole is much improved on the situation reported earlier

  16. Experimental determination of electron shock excitation cross sections for a singly charged gadolinium ion

    International Nuclear Information System (INIS)

    Smirnov, Yu.M.

    1995-01-01

    The trends observed in the processes of excitation with simultaneous ionization have received little study. This is particularly so for rare-earth elements having electron shells of complex structure and optical spectra very rich in lines. Among the basic factors responsible for such a situation, we should mention two: the difficulty presented by theoretical analysis of the processes discussed and the absence of factual information about the excitation cross sections with simultaneous ionization for the majority of rare-earth elements. The aim of the present work is to investigate the excitation of a singly charged gadolinium ion in the collisions of monokinetic electrons with gadolinium atoms. Up to the present time, only the excitation cross sections of a gadolinium atom have been measured, where investigation of the electron shock excitation of gadolinium atoms in their free state is associated with overcoming large experimental difficulties. About 160 crosss sections for the excitation of a singly charged gadolinium ion were measured and for a third of the cross sections; the energy dependences were recorded for the change in energy of the elecrons from the excitation threshold up to 200 eV. Included are tables of the wavelength, transistion, internal quantum number, the energy of the lowere and upper levels, and the values of cross sections for the charged gadolinium ion. Diagrams of the transistion energy states of Gd (II) and spectroscopy are presented and explained

  17. Tuning of Hemes b Equilibrium Redox Potential Is Not Required for Cross-Membrane Electron Transfer.

    Science.gov (United States)

    Pintscher, Sebastian; Kuleta, Patryk; Cieluch, Ewelina; Borek, Arkadiusz; Sarewicz, Marcin; Osyczka, Artur

    2016-03-25

    In biological energy conversion, cross-membrane electron transfer often involves an assembly of two hemesb The hemes display a large difference in redox midpoint potentials (ΔEm_b), which in several proteins is assumed to facilitate cross-membrane electron transfer and overcome a barrier of membrane potential. Here we challenge this assumption reporting on hemebligand mutants of cytochromebc1in which, for the first time in transmembrane cytochrome, one natural histidine has been replaced by lysine without loss of the native low spin type of heme iron. With these mutants we show that ΔEm_b can be markedly increased, and the redox potential of one of the hemes can stay above the level of quinone pool, or ΔEm_b can be markedly decreased to the point that two hemes are almost isopotential, yet the enzyme retains catalytically competent electron transfer between quinone binding sites and remains functionalin vivo This reveals that cytochromebc1can accommodate large changes in ΔEm_b without hampering catalysis, as long as these changes do not impose overly endergonic steps on downhill electron transfer from substrate to product. We propose that hemesbin this cytochrome and in other membranous cytochromesbact as electronic connectors for the catalytic sites with no fine tuning in ΔEm_b required for efficient cross-membrane electron transfer. We link this concept with a natural flexibility in occurrence of several thermodynamic configurations of the direction of electron flow and the direction of the gradient of potential in relation to the vector of the electric membrane potential. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Calculation of the differential cross sections of excitation and ionization of a helium atom by electrons

    International Nuclear Information System (INIS)

    Demkin, V.P.; Pecheritsyn, A.A.

    1995-01-01

    Equations for the amplitudes and differential cross sections of electronic excitation and ionization of a helium atom are derived in the approximation of a open-quotes frozenclose quotes ion core. The wave functions of the discrete states are chosen in the form of generalized hydrogenlike orbitals. The radial wave functions of the continuous spectrum are determined by solving the equation of motion numerically. The differential excitation cross sections of excitation of the 2p, 3p, and 4p levels and ionization of a helium atom by electrons are calculated in the energy range up to 50 eV. Estimates are obtained for the nonorthogonal wave functions in the amplitudes of the excitation and ionization processes. It is shown that the given method is more compatible with experiment than the Born method

  19. Electron molecule cross sections relevant to negative ion sources and divertor plasmas

    International Nuclear Information System (INIS)

    Celiberto, R.; Capitelli, M.; Lamanna, U.T.; Janev, R.K.

    1996-01-01

    Electron-molecule cross sections for electronic transitions in H 2 and D 2 molecules vibrationally excited are presented, and a scaling law for the vibrational cross sections is discussed for the X 1 summation + g →B 1 summation + u electronic transition. copyright 1996 American Institute of Physics

  20. Cross sections for inelastic scattering of electrons by atoms: selected topics related to electron microscopy

    International Nuclear Information System (INIS)

    Inokuti, M.; Manson, S.T.

    1982-01-01

    We begin with a resume of the Bethe theory, which provides a general framework for discussing the inelastic scattering of fast electrons and leads to powerful criteria for judging the reliability of cross-section data. The central notion of the theory is the generalized oscillator strength as a function of both the energy transfer and the momentum transfer, and is the only non-trivial factor in the inelastic-scattering cross section. Although the Bethe theory was initially conceived for free atoms, its basic ideas apply to solids, with suitable generalizations; in this respect, the notion of the dielectric response function is the most fundamental. Topics selected for discussion include the generalized oscillator strengths for the K-shell and L-shell ionization for all atoms with Z less than or equal to 30, evaluated by use of the Hartree-Slater potential. As a function of the energy transfer, the generalized oscillator strength most often shows a non-monotonic structure near the K-shell and L-shell thresholds, which has been interpreted as manifestations of electron-wave propagation through atomic fields. For molecules and solids, there are additional structures due to the scattering of ejected electrons by the fields of other atoms

  1. Electronic structure and self-assembly of cross-linked semiconductor nanocrystal arrays

    International Nuclear Information System (INIS)

    Steiner, Dov; Azulay, Doron; Aharoni, Assaf; Salant, Assaf; Banin, Uri; Millo, Oded

    2008-01-01

    We studied the electronic level structure of assemblies of InAs quantum dots and CdSe nanorods cross-linked by 1,4-phenylenediamine molecules using scanning tunneling spectroscopy. We found that the bandgap in these arrays is reduced with respect to the corresponding ligand-capped nanocrystal arrays. In addition, a pronounced sub-gap spectral structure commonly appeared which can be attributed to unpassivated nanocrystal surface states or associated with linker-molecule-related levels. The exchange of the ligands by the linker molecules also affected the structural array properties. Most significantly, clusters of close-packed standing CdSe nanorods were formed

  2. Jet cross sections in electron-positron annihilation

    International Nuclear Information System (INIS)

    Sharpe, S.R.

    1983-08-01

    There are few, if any, detailed tests of QCD at present. I disucss the problems associated with testing QCD and argue that the three jet angular distribution in electron-positron annihilation is a good quantity to use because it minimizes the sensitivity to nonperturbative effects and provides a test of the detailed structure of QCD. However, for such a test to be possible, the perturbation expansion must be well behaved. I present a calculation of the perturbative corrections using two different generalizations of the Sterman-Weinberg two-jet cross section. I argue that because of the uncertainties in our understanding of hadronization it is necessary that the corrections to both these cross sections be small. In presenting the results I use the recent proof of Mukti and Sterman that all the logarithms can be resummed. I find that at Z-factory energies there is a substantial region of parameters defining the jets for which the correction is small, but that there is no such region at PEP/PETRA energies. This problem at PEP/PETRA energies is made worse by the results of a study of the effects of hadronization. Using a simple model I find very significant effects at PEP/PETRA energies that would make a test difficult. These effects do not, however, present problems at Z-factory energies. I conclude that, even if there are further theoretical advances, testing QCD at PEP/PETRA energies using the three-jet angular distribution will be very difficult. However, this distribution can be used to test QCD in a detailed way at Z-factory energies. The corrected results, furthermore, show a systematic difference from the lowest order result that may be measurable at Z-factory energies. If this effect could be measured it would provide a yet more detailed test of QCD, testing, for example, the three gluon coupling. 66 references

  3. Cross sections for electron and photon processes required by electron-transport calculations

    International Nuclear Information System (INIS)

    Peek, J.M.

    1979-11-01

    Electron-transport calculations rely on a large collection of electron-atom and photon-atom cross-section data to represent the response characteristics of the target medium. These basic atomic-physics quantities, and certain qualities derived from them that are now commonly in use, are critically reviewed. Publications appearing after 1978 are not given consideration. Processes involving electron or photon energies less than 1 keV are ignored, while an attempt is made to exhaustively cover the remaining independent parameters and target possibilities. Cases for which data improvements can be made from existing information are identified. Ranges of parameters for which state-of-the-art data are not available are sought out, and recommendations for explicit measurements and/or calculations with presently available tools are presented. An attempt is made to identify the maturity of the atomic-physics data and to predict the possibilities for rapid changes in the quality of the data. Finally, weaknesses in the state-of-the-art atomic-physics data and in the conceptual usage of these data in the context of electron-transport theory are discussed. Brief attempts are made to weight the various aspects of these questions and to suggest possible remedies

  4. Authors' perceptions of electronic publishing: two cross sectional surveys.

    Science.gov (United States)

    Schroter, Sara; Barratt, Helen; Smith, Jane

    2004-06-05

    To evaluate how acceptable authors find the BMJ's current practice of publishing short versions of research articles in the paper journal and a longer version on the web and to determine authors' attitudes towards publishing only abstracts in the paper journal and publishing unedited versions on bmj.com once papers have been accepted for publication. Two cross sectional surveys. General medical journal. Survey 1: corresponding authors of a consecutive sample of published BMJ research articles that had undergone the ELPS (electronic long, paper short) process. Survey 2: corresponding authors of consecutive research articles submitted to BMJ. Response rates were 90% (104/115) in survey 1 and 75% (213/283) in survey 2. ELPS is largely acceptable to BMJ authors, but there is some concern that electronic information is not permanent and uncertainty about how versions are referenced. While authors who had experienced ELPS reported some problems with editors shortening papers, most were able to rectify these. Overall, 70% thought that the BMJ should continue to use ELPS; 49% thought that publishing just the abstract in the printed journal with the full version only on bmj.com was unacceptable; and 23% thought it unacceptable to post unedited versions on bmj.com once a paper had been accepted for publication. It is acceptable to authors to publish short versions of research articles in the printed version of a general medical journal with longer versions on the website. Authors dislike the idea of publishing only abstracts in the printed journal but are in favour of posting accepted articles on the website ahead of the printed version.

  5. Electron Cross-field Transport in a Miniaturized Cylindrical Hall Thruster

    International Nuclear Information System (INIS)

    Smirnov Artem; Raitses Yevgeny; Fisch Nathaniel J

    2005-01-01

    Conventional annular Hall thrusters become inefficient when scaled to low power. Cylindrical Hall thrusters, which have lower surface-to-volume ratio, are more promising for scaling down. They presently exhibit performance comparable with conventional annular Hall thrusters. The present paper gives a review of the experimental and numerical investigations of electron crossfield transport in the 2.6 cm miniaturized cylindrical Hall thruster (100 W power level). We show that, in order to explain the discharge current observed for the typical operating conditions, the electron anomalous collision frequency ν b has to be on the order of the Bohm value, ν B ∼ ω c /16. The contribution of electron-wall collisions to cross-field transport is found to be insignificant. The optimal regimes of thruster operation at low background pressure (below 10 -5 Torr) in the vacuum tank appear to be different from those at higher pressure (∼ 10 -4 Torr)

  6. Pseudo Asynchronous Level Crossing adc for ecg Signal Acquisition.

    Science.gov (United States)

    Marisa, T; Niederhauser, T; Haeberlin, A; Wildhaber, R A; Vogel, R; Goette, J; Jacomet, M

    2017-02-07

    A new pseudo asynchronous level crossing analogue-to-digital converter (adc) architecture targeted for low-power, implantable, long-term biomedical sensing applications is presented. In contrast to most of the existing asynchronous level crossing adc designs, the proposed design has no digital-to-analogue converter (dac) and no continuous time comparators. Instead, the proposed architecture uses an analogue memory cell and dynamic comparators. The architecture retains the signal activity dependent sampling operation by generating events only when the input signal is changing. The architecture offers the advantages of smaller chip area, energy saving and fewer analogue system components. Beside lower energy consumption the use of dynamic comparators results in a more robust performance in noise conditions. Moreover, dynamic comparators make interfacing the asynchronous level crossing system to synchronous processing blocks simpler. The proposed adc was implemented in [Formula: see text] complementary metal-oxide-semiconductor (cmos) technology, the hardware occupies a chip area of 0.0372 mm 2 and operates from a supply voltage of [Formula: see text] to [Formula: see text]. The adc's power consumption is as low as 0.6 μW with signal bandwidth from [Formula: see text] to [Formula: see text] and achieves an equivalent number of bits (enob) of up to 8 bits.

  7. Cross-section transmission electron microscopy of the ion implantation damage in annealed diamond

    Energy Technology Data Exchange (ETDEWEB)

    Derry, T.E. [DST/NRF Centre of Excellence in Strong Materials and School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa)], E-mail: Trevor.Derry@wits.ac.za; Nshingabigwi, E.K. [DST/NRF Centre of Excellence in Strong Materials and School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa); Department of Physics, National University of Rwanda, P.O. Box 117, Huye (Rwanda); Levitt, M. [DST/NRF Centre of Excellence in Strong Materials and School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa); Neethling, J. [DST/NRF CoE-SM and Physics Department, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Naidoo, S.R. [DST/NRF Centre of Excellence in Strong Materials and School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa)

    2009-08-15

    It has formerly been shown that low-damage levels, produced during the implantation doping of diamond as a semiconductor, anneal easily while high levels 'graphitize' (above about 5.2 x 10{sup 15} ions/cm{sup 2}). The difference in the defect types and their profiles, in the two cases, has never been directly observed. We have succeeded in using cross-section transmission electron microscopy to do so. The experiments were difficult because the specimens must be polished to {approx}40 {mu}m thickness, then implanted on edge and annealed, before final ion beam thinning to electron transparency. The low-damage micrographs reveal some deeply penetrating dislocations, whose existence had been predicted in earlier work.

  8. Cross-section transmission electron microscopy of the ion implantation damage in annealed diamond

    International Nuclear Information System (INIS)

    Derry, T.E.; Nshingabigwi, E.K.; Levitt, M.; Neethling, J.; Naidoo, S.R.

    2009-01-01

    It has formerly been shown that low-damage levels, produced during the implantation doping of diamond as a semiconductor, anneal easily while high levels 'graphitize' (above about 5.2 x 10 15 ions/cm 2 ). The difference in the defect types and their profiles, in the two cases, has never been directly observed. We have succeeded in using cross-section transmission electron microscopy to do so. The experiments were difficult because the specimens must be polished to ∼40 μm thickness, then implanted on edge and annealed, before final ion beam thinning to electron transparency. The low-damage micrographs reveal some deeply penetrating dislocations, whose existence had been predicted in earlier work.

  9. Electron capture cross sections by O+ from atomic He

    International Nuclear Information System (INIS)

    Joseph, Dwayne C; Saha, Bidhan C

    2009-01-01

    The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections

  10. Electron capture cross sections by O+ from atomic He

    Science.gov (United States)

    Joseph, Dwayne C.; Saha, Bidhan C.

    2009-11-01

    The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections

  11. Electron transport in furfural: dependence of the electron ranges on the cross sections and the energy loss distribution functions

    Science.gov (United States)

    Ellis-Gibbings, L.; Krupa, K.; Colmenares, R.; Blanco, F.; Muńoz, A.; Mendes, M.; Ferreira da Silva, F.; Limá Vieira, P.; Jones, D. B.; Brunger, M. J.; García, G.

    2016-09-01

    Recent theoretical and experimental studies have provided a complete set of differential and integral electron scattering cross section data from furfural over a broad energy range. The energy loss distribution functions have been determined in this study by averaging electron energy loss spectra for different incident energies and scattering angles. All these data have been used as input parameters for an event by event Monte Carlo simulation procedure to obtain the electron energy deposition patterns and electron ranges in liquid furfural. The dependence of these results on the input cross sections is then analysed to determine the uncertainty of the simulated values.

  12. Electron Energy Level Statistics in Graphene Quantum Dots

    NARCIS (Netherlands)

    De Raedt, H.; Katsnellson, M. I.; Katsnelson, M.I.

    2008-01-01

    Motivated by recent experimental observations of size quantization of electron energy levels in graphene quantum dots [7] we investigate the level statistics in the simplest tight-binding model for different dot shapes by computer simulation. The results are in a reasonable agreement with the

  13. Observation of molecular level behavior in molecular electronic junction device

    Science.gov (United States)

    Maitani, Masato

    In this dissertation, I utilize AFM based scanning probe measurement and surface enhanced Raman scattering based vibrational spectroscopic analysis to directly characterize topographic, electronic, and chemical properties of molecules confined in the local area of M3 junction to elucidate the molecular level behavior of molecular junction electronic devices. In the introduction, the characterization of molecular electronic devices with different types of metal-molecule-metal (M3) structures based upon self-assembled monolayers (SAMs) is reviewed. A background of the characterization methods I use in this dissertation, conducting probe atomic force microscopy (cp-AFM) and surface enhanced Raman spectroscopy (SERS), is provided in chapter 1. Several attempts are performed to create the ideal top metal contacts on SAMs by metal vapor phase deposition in order to prevent the metal penetration inducing critical defects of the molecular electronic devices. The scanning probe microscopy (SPM), such as cp-AFM, contact mode (c-) AFM and non-contact mode (nc-) AFM, in ultra high vacuum conditions are utilized to study the process of the metal-SAM interface construction in terms of the correlation between the morphological and electrical properties including the metal nucleation and filament generation as a function of the functionalization of long-chain alkane thiolate SAMs on Au. In chapter 2, the nascent condensation process of vapor phase Al deposition on inert and reactive SAMs are studied by SPM. The results of top deposition, penetration, and filament generation of deposited Al are discussed and compared to the results previously observed by spectroscopic measurements. Cp-AFM was shown to provide new insights into Al filament formation which has not been observed by conventional spectroscopic analysis. Additionally, the electronic characteristics of individual Al filaments are measured. Chapter 3 reveals SPM characterization of Au deposition onto --COOH terminated SAMs

  14. Effectiveness of trimethylopropane trimethacrylate for the electron-beam-irradiation-induced cross-linking of polylactic acid

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Hon-Meng [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Bee, Soo-Tueen, E-mail: beest@utar.edu.my [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Ratnam, C.T. [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Sin, Lee Tin; Phang, Yee-Yao; Tee, Tiam-Ting [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Rahmat, A.R. [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

    2014-01-15

    Highlights: • Investigation of trimethylopropane trimethacrylate (TMPTMA) on electron beam irradiated PLA. • Irradiated PLA blends were weakened by incorporation of high amount of TMPTMA. • TMPTMA interacts with polymer free radicals to build crosslinking network. -- Abstract: The purpose of this research was to investigate the effects of various loading levels of trimethylopropane trimethacrylate (TMPTMA) on the properties of polylactic acid (PLA) cross-linked via electron-beam irradiation. PLA was compounded with 3–5 wt.% of TMPTMA to induce cross-linking upon subjection to electron-beam irradiation doses of 25–250 kGy. The physical properties of the PLA samples were characterised by means of X-ray diffraction, gel fraction and scanning electron microscopy analyses on fractured surfaces after tensile tests. The presence of TMPTMA in PLA was found to effectively increase the crystallite size and gel fraction. However, higher loading levels of TMPTMA could compromise the properties of the PLA/TMPTMA samples, indicating that a larger amount of monomer free radicals might promote degradation within the substantially cross-linked amorphous phase. Irradiation-induced cross-linking in the samples could improve the cross-linking density while decreasing the elongation and interfering with the crystallisation. These effects are caused by the intensive irradiation-induced chain scission that is responsible for the deterioration of the mechanical and crystalline properties of the samples.

  15. Effectiveness of trimethylopropane trimethacrylate for the electron-beam-irradiation-induced cross-linking of polylactic acid

    International Nuclear Information System (INIS)

    Ng, Hon-Meng; Bee, Soo-Tueen; Ratnam, C.T.; Sin, Lee Tin; Phang, Yee-Yao; Tee, Tiam-Ting; Rahmat, A.R.

    2014-01-01

    Highlights: • Investigation of trimethylopropane trimethacrylate (TMPTMA) on electron beam irradiated PLA. • Irradiated PLA blends were weakened by incorporation of high amount of TMPTMA. • TMPTMA interacts with polymer free radicals to build crosslinking network. -- Abstract: The purpose of this research was to investigate the effects of various loading levels of trimethylopropane trimethacrylate (TMPTMA) on the properties of polylactic acid (PLA) cross-linked via electron-beam irradiation. PLA was compounded with 3–5 wt.% of TMPTMA to induce cross-linking upon subjection to electron-beam irradiation doses of 25–250 kGy. The physical properties of the PLA samples were characterised by means of X-ray diffraction, gel fraction and scanning electron microscopy analyses on fractured surfaces after tensile tests. The presence of TMPTMA in PLA was found to effectively increase the crystallite size and gel fraction. However, higher loading levels of TMPTMA could compromise the properties of the PLA/TMPTMA samples, indicating that a larger amount of monomer free radicals might promote degradation within the substantially cross-linked amorphous phase. Irradiation-induced cross-linking in the samples could improve the cross-linking density while decreasing the elongation and interfering with the crystallisation. These effects are caused by the intensive irradiation-induced chain scission that is responsible for the deterioration of the mechanical and crystalline properties of the samples

  16. Comparison of fatal motor vehicle accidents at passive and active railway level crossings in Finland

    Directory of Open Access Journals (Sweden)

    Sirkku Laapotti

    2016-07-01

    Active warning devices are effective in preventing accidents due to road user errors. Equipping the most dangerous passive level crossings with warning devices – low cost or conventional – would increase safety. Alternatively, some level crossings could be removed altogether. A minimum requirement is that the environmental factors at passive level crossings support safe crossing.

  17. CrossFlow: integrating workflow management and electronic commerce

    NARCIS (Netherlands)

    Hoffner, Y.; Ludwig, H.; Grefen, P.W.P.J.; Aberer, K.

    2001-01-01

    The CrossFlow architecture provides support for cross-organisational workflow management in dynamically established virtual enterprises. The creation of a business relationship between a service provider organisation performing a service on behalf of a consumer organisation can be made dynamic when

  18. CrossFlow: Integrating Workflow Management and Electronic Commerce

    NARCIS (Netherlands)

    Hoffner, Y.; Ludwig, H.; Grefen, P.W.P.J.; Aberer, K.

    2001-01-01

    The CrossFlow1 architecture provides support for cross-organisational workflow management in dynamically established virtual enterprises. The creation of a business relationship between a service provider organisation performing a service on behalf of a consumer organisation can be made dynamic when

  19. Differential elastic electron scattering cross sections for CCl4 by 1.5-100 eV energy electron impact

    Science.gov (United States)

    Limão-Vieira, P.; Horie, M.; Kato, H.; Hoshino, M.; Blanco, F.; García, G.; Buckman, S. J.; Tanaka, H.

    2011-12-01

    We report absolute elastic differential, integral and momentum transfer cross sections for electron interactions with CCl4. The incident electron energy range is 1.5-100 eV, and the scattered electron angular range for the differential measurements varies from 15°-130°. The absolute scale of the differential cross section was set using the relative flow technique with helium as the reference species. Comparison with previous total cross sections shows good agreement. Atomic-like behaviour in this scattering system is shown here for the first time, and is further investigated by comparing the CCl4 elastic cross sections to recent results on the halomethanes and atomic chlorine at higher impact energies [H. Kato, T. Asahina, H. Masui, M. Hoshino, H. Tanaka, H. Cho, O. Ingólfsson, F. Blanco, G. Garcia, S. J. Buckman, and M. J. Brunger, J. Chem. Phys. 132, 074309 (2010)], 10.1063/1.3319761.

  20. Dependence of radar auroral scattering cross section on the ambient electron density and the destabilizing electric field

    International Nuclear Information System (INIS)

    Haldoupis, C.; Nielsen, E.; Schlegel, K.

    1990-01-01

    By using a data set that includes simultaneous STARE and EISCAT measurements made at a common magnetic flux tube E region in the ionosphere, we investigate the dependence of relative scattering cross section of 1-meter auroral irregularities on the destabilizing E x B electron drift, or alternatively the electric field, and the E region ambient electron density. The analysis showed that both, the E field and mean electron density are the decisive factors in determining the strength of radar auroral echoes at magnetic aspect angles near perpendicularity. We have found that at instability threshold, i.e., when the E field strength is in the 15 to 20 mV/m range, the backscatter power level is affected strongly by the mean electron density. Above threshold, the wave saturation amplitudes are determined mainly by the combined action of electron drift velocity magnitude, V d , and mean electron density, N e , in a way that the scattering cross section, or the electron density fluctuation level, increases with electric field magnitude but at a rate which is larger when the ambient electron density is lower. The analysis enabled us to infer an empirical functional relationship which is capable of predicting reasonably well the intensity of STARE echoes from EISCAT E field and electron density data. In this functional relationship, the received power at threshold depends on N e 2 whereas, from threshold to perhaps more than 50 mV/m, the power increases nonlinearly with drift velocity as V d n where the exponent n is approximately proportional to N e -1/2 . The results support the Farley-Bunemann instability as the primary instability mechanism, but the existing nonlinear treatment of the theory, which includes wave-induced cross field diffusion, cannot account for the observed role of electron density in the saturation of irregularity amplitudes

  1. Improved calculation of displacements per atom cross section in solids by gamma and electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Piñera, Ibrahin, E-mail: ipinera@ceaden.edu.cu [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, CEADEN, 30 St. 502, Playa 11300, Havana (Cuba); Cruz, Carlos M.; Leyva, Antonio; Abreu, Yamiel; Cabal, Ana E. [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, CEADEN, 30 St. 502, Playa 11300, Havana (Cuba); Espen, Piet Van; Remortel, Nick Van [University of Antwerp, CGB, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)

    2014-11-15

    Highlights: • We present a calculation procedure for dpa cross section in solids under irradiation. • Improvement about 10–90% for the gamma irradiation induced dpa cross section. • Improvement about 5–50% for the electron irradiation induced dpa cross section. • More precise results (20–70%) for thin samples irradiated with electrons. - Abstract: Several authors had estimated the displacements per atom cross sections under different approximations and models, including most of the main gamma- and electron-material interaction processes. These previous works used numerical approximation formulas which are applicable for limited energy ranges. We proposed the Monte Carlo assisted Classical Method (MCCM), which relates the established theories about atom displacements to the electron and positron secondary fluence distributions calculated from the Monte Carlo simulation. In this study the MCCM procedure is adapted in order to estimate the displacements per atom cross sections for gamma and electron irradiation. The results obtained through this procedure are compared with previous theoretical calculations. An improvement in about 10–90% for the gamma irradiation induced dpa cross section is observed in our results on regard to the previous evaluations for the studied incident energies. On the other hand, the dpa cross section values produced by irradiation with electrons are improved by our calculations in about 5–50% when compared with the theoretical approximations. When thin samples are irradiated with electrons, more precise results are obtained through the MCCM (in about 20–70%) with respect to the previous studies.

  2. An electron microscopic study of the photochemical cross-linking of DNA in guinea pig epidermis by psoralen derivatives

    International Nuclear Information System (INIS)

    Cech, T.; Pathak, M.A.; Biswas, R.K.

    1979-01-01

    Albino guinea pigs were treated with psoralen derivatives plus 320-400 nm ultraviolet radiation, and DNA was extracted from their epidermis. The DNA was assayed for the presence of interstrand cross-links by standard denaturation-renaturation assays and by a new technique, electron microscopy of the DNA under totally denaturing conditions. The latter method allows individual cross-links to be directly observed and counted. When either 4,5',8-trimethylpsoralen or 8-methoxypsoralen was applied topically to the skin (8-20 μg/cm 2 ) or administered orally (10-12 mg/kg body weight), followed by exposure to 320-400 nm ultraviolet radiation, most of the epidermal DNA was found to contain a high frequency of cross-links. For example, oral or topical trimethylpsoralen treatment gave an average of one cross-link per 250 nucleotide pairs or about 3 . 10 5 cross-links per guinea pig chromosome. When the dose of either drug was decreased 20-fold to the level used in the clinical treatment of psoriasis, however, no cross-links could be detected in the epidermal DNA. The electron microscopic assay is sensitive enough that one can put an upper limit of 1 cross-link per 10 6 nucleotide pairs (80 cross-links per chromosome) for the low dose studies. The significance of these findings to the understanding of the effectiveness of psoralens in psoriasis therapy is discussed. (Auth.)

  3. Measurement of cross-sections for step-bystep excitation of inert gas atoms from metastable states by electron collisions

    International Nuclear Information System (INIS)

    Mityureva, A.A.; Penkin, N.P.; Smirnov, V.V.

    1989-01-01

    Excitation of argon atoms by electron collisions from metastable (MS) to high-lying states of inert gases (the so-called step-by-step excitation) is investigated. Formation of MS atoms m and their further step-by-step excitation up to k level is carried out by an electron beam with energy from 1 up to 40 eV. Time distribution of forming metastable and step-by-step electron collisions is used. The method used permits to measure the functions of step-by-step excitation and the absolute values of cross sections. Absolute values of cross-sections and functions of step-by-step excitation of some lines and argon levels are obtained

  4. The upper level of control system of electron accelerators

    International Nuclear Information System (INIS)

    Gribov, I.V.; Nedeoglo, F.N.; Shvedunov, I.V.

    2005-01-01

    The upper level software of a three-level control system that supports several electron accelerators is described. This software operates in the Linux and RTLinux (Real Time Linux) environment. The object information model functions on the basis of a parametric description supported by the SQLite Data Base Management System. The Javascript sublanguage is used for script forming, and the Qt Designer application is used to construct the user interface [ru

  5. Interaction between electrons and tunneling levels in metallic glasses

    International Nuclear Information System (INIS)

    Black, J.L.; Gyorffy, B.L.

    1978-01-01

    A simple model in which the conduction electrons of a metallic glass experience a local time-dependent potential due to two-level tunneling states is considered. The model exhibits interesting divergent behavior which is quite different from that predicted by an earlier ''s-d Kondo'' model

  6. Ionization of xenon by electrons: Partial cross sections for single, double, and triple ionization

    International Nuclear Information System (INIS)

    Mathur, D.; Badrinathan, C.

    1987-01-01

    High-sensitivity measurements of relative partial cross sections for single, double, and triple ionization of Xe by electron impact have been carried out in the energy region from threshold to 100 eV using a crossed-beam apparatus incorporating a quadrupole mass spectrometer. The weighted sum of the relative partial cross sections at 50 eV are normalized to the total ionization cross section of Rapp and Englander-Golden to yield absolute cross-section functions. Shapes of the partial cross sections for single and double ionization are difficult to account for within a single-particle picture. Comparison of the Xe + data with 4d partial photoionization cross-section measurements indicates the important role played by many-body effects in describing electron-impact ionization of high-Z atoms

  7. Excitation and deexcitation of N2 molecular levels. Induced fluorescence by electrons and laser

    International Nuclear Information System (INIS)

    Perez Fernandez-Mayoralas, A.

    1989-01-01

    The electron impact excitation followed by fluorescence induced by N 2 -laser absorption was used to study the lifetime of the lowest vibrational level of the B 3 π g electronic state of N 2 . The experimental result of this work is 13 + 1 μs. To measure the lifetime of B 3 π g (v=2,3,5,6,7,8) levels the delayed coincidence method by electron impact was use. The lifetime values were compared with recent experimental and theoretical results. The relative intensi-ties of 3 π g --- A 3 Σ Ω + system bands, in the range (6540-10500 A o ) was measured using a hollow cathode lamp as spectral source. The relative transition moments and its dependence versus the r-centroid was obtained. Total cross sections for electron scattering by N molecules in the range 600 - 5000 eV have been obtained from measurements of the attenuation of a linear electron beam. The results have been compared with available experimental cross sections and with theoretical calculations based on the first Born approximation. (Author)

  8. Tree-level equivalence between a Lorentz-violating extension of QED and its dual model in electron-electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Toniolo, Giuliano R.; Fargnoli, H.G.; Brito, L.C.T. [Universidade Federal de Lavras, Departamento de Fisica, Caixa Postal 3037, Lavras, Minas Gerais (Brazil); Scarpelli, A.P.B. [Setor Tecnico-Cientifico, Departamento de Policia Federal, Sao Paulo (Brazil)

    2017-02-15

    S-matrix amplitudes for the electron-electron scattering are calculated in order to verify the physical equivalence between two Lorentz-breaking dual models. We begin with an extended Quantum Electrodynamics which incorporates CPT-even Lorentz-violating kinetic and mass terms. Then, in a process of gauge embedding, its gauge-invariant dual model is obtained. The physical equivalence of the two models is established at tree level in the electron-electron scattering and the unpolarized cross section is calculated up to second order in the Lorentz-violating parameter. (orig.)

  9. Tree-level equivalence between a Lorentz-violating extension of QED and its dual model in electron-electron scattering

    International Nuclear Information System (INIS)

    Toniolo, Giuliano R.; Fargnoli, H.G.; Brito, L.C.T.; Scarpelli, A.P.B.

    2017-01-01

    S-matrix amplitudes for the electron-electron scattering are calculated in order to verify the physical equivalence between two Lorentz-breaking dual models. We begin with an extended Quantum Electrodynamics which incorporates CPT-even Lorentz-violating kinetic and mass terms. Then, in a process of gauge embedding, its gauge-invariant dual model is obtained. The physical equivalence of the two models is established at tree level in the electron-electron scattering and the unpolarized cross section is calculated up to second order in the Lorentz-violating parameter. (orig.)

  10. Doubly differential cross sections for ionization of helium by electron impact

    International Nuclear Information System (INIS)

    Ray, H.; Werner, U.; Roy, A.C.

    1991-01-01

    The Glauber approximation is used to calculate doubly differential cross sections (DDCS's) for electron-impact ionization of helium at incident energies of 100, 300, and 500 eV. Angular dependences of the cross sections are presented for the primary (scattered) electrons. The present calculation is done for the case where the energy of the primary electron is large compared with that of the secondary (ejected) electron. A comparison is made of the present DDCS with the results of other calculations and experiment

  11. Images crossing borders: image and workflow sharing on multiple levels.

    Science.gov (United States)

    Ross, Peeter; Pohjonen, Hanna

    2011-04-01

    Digitalisation of medical data makes it possible to share images and workflows between related parties. In addition to linear data flow where healthcare professionals or patients are the information carriers, a new type of matrix of many-to-many connections is emerging. Implementation of shared workflow brings challenges of interoperability and legal clarity. Sharing images or workflows can be implemented on different levels with different challenges: inside the organisation, between organisations, across country borders, or between healthcare institutions and citizens. Interoperability issues vary according to the level of sharing and are either technical or semantic, including language. Legal uncertainty increases when crossing national borders. Teleradiology is regulated by multiple European Union (EU) directives and legal documents, which makes interpretation of the legal system complex. To achieve wider use of eHealth and teleradiology several strategic documents were published recently by the EU. Despite EU activities, responsibility for organising, providing and funding healthcare systems remains with the Member States. Therefore, the implementation of new solutions requires strong co-operation between radiologists, societies of radiology, healthcare administrators, politicians and relevant EU authorities. The aim of this article is to describe different dimensions of image and workflow sharing and to analyse legal acts concerning teleradiology in the EU.

  12. Cross section determination for the higher ionization of rare gas ions by electron collisions

    International Nuclear Information System (INIS)

    Becker, R.; Frodl, R.; Klein, H.; Schmidt, W.; Clausnitzer, G.; Klinger, H.; Mueller, A.; Salzborn, E.; Fuchs, G.; Viehboeck, F.

    1975-01-01

    The higher ionization of rare gas ions is reported on, which were excited by an electron beam using a crossed-beam technique. A detector for the identification of metastable excited rare gas ions was developed. (WL) [de

  13. Cross section formulae on single W and Z boson productions in electron-positron collisions

    International Nuclear Information System (INIS)

    Katuya, Mituaki

    1987-01-01

    The formulae are given for the transverse momentum distributions and total cross sections for the single W boson and Z boson productions in electron-positron collisions by using the equivalent photon approximation. (author)

  14. Activity of flavonoids through λ sub max and electron cross-section

    International Nuclear Information System (INIS)

    Murthy, V.R.; Sreenivasulu, M.

    1997-01-01

    Flavonoids are widespread groups of natural constituents and present in the drugs in the form of mono or diglycosides. Being physiologically active, flavonoids are important in the field of pharmacological and clinical applications. Not many physical properties of flavonoids have been studied so far excepting UV and NMR studies. This paper deals with the evaluation of electron ionization cross section through λ sub max, a parameter available from UV studies. Electron ionization cross section was primarily conceived to be of use in radiation chemical data, mass spectroscopic and thermodynamic studies. But later attempts to correlate electron ionization cross-section with structural and related parameters prompted the authors to derive an explicit expression relating λ sub max and electron ionization cross-section (Q). The application of this method to correlate Q through λ sub max and interpret the results in terms of chemical activity are discussed

  15. Compilation of excitation cross sections for He atoms by electron impact

    International Nuclear Information System (INIS)

    Kato, T.; Itikawa, Y.; Sakimoto, K.

    1992-03-01

    Experimental and theoretical data are compiled on the cross section for the excitation of He atoms by electron impact. The available data are compared graphically. The survey of the literature has been made through the end 1991. (author)

  16. Electron bombardment cross-linking of coating materials

    International Nuclear Information System (INIS)

    Mileo, J.-C.

    1976-01-01

    The use of medium-power electron accelerators to cure paints and varnishes and to make them insoluble is described by making a special analysis of the physico-chemical aspect of the process. The following points in particular are examined: the effect of radiation on matter; general aspects of radiochemical polymerization, and the application of radiation polymerization to varnish drying. A quick review is then made of problems linked to the choice of radiation and to the influence of the oxygen in air. An electron accelerator and a method of calorimetric dosimetery are described [fr

  17. Absolute cross sections from the ''boomerang model'' for resonant electron-molecule scattering

    International Nuclear Information System (INIS)

    Dube, L.; Herzenberg, A.

    1979-01-01

    The boomerang model is used to calculate absolute cross sections near the 2 Pi/sub g/ shape resonance in e-N 2 scattering. The calculated cross sections are shown to satisfy detailed balancing. The exchange of electrons is taken into account. A parametrized complex-potential curve for the intermediate N 2 /sup ts-/ ion is determined from a small part of the experimental data, and then used to calculate other properties. The calculations are in good agreement with the absolute cross sections for vibrational excitation from the ground state, the absolute cross section v = 1 → 2, and the absolute total cross section

  18. Adaptive Reference Levels in a Level-Crossing Analog-to-Digital Converter

    Directory of Open Access Journals (Sweden)

    Andrew C. Singer

    2008-11-01

    Full Text Available Level-crossing analog-to-digital converters (LC ADCs have been considered in the literature and have been shown to efficiently sample certain classes of signals. One important aspect of their implementation is the placement of reference levels in the converter. The levels need to be appropriately located within the input dynamic range, in order to obtain samples efficiently. In this paper, we study optimization of the performance of such an LC ADC by providing several sequential algorithms that adaptively update the ADC reference levels. The accompanying performance analysis and simulation results show that as the signal length grows, the performance of the sequential algorithms asymptotically approaches that of the best choice that could only have been chosen in hindsight within a family of possible schemes.

  19. Calculation of total and ionization cross sections for electron scattering by primary benzene compounds

    Science.gov (United States)

    Singh, Suvam; Naghma, Rahla; Kaur, Jaspreet; Antony, Bobby

    2016-07-01

    The total and ionization cross sections for electron scattering by benzene, halobenzenes, toluene, aniline, and phenol are reported over a wide energy domain. The multi-scattering centre spherical complex optical potential method has been employed to find the total elastic and inelastic cross sections. The total ionization cross section is estimated from total inelastic cross section using the complex scattering potential-ionization contribution method. In the present article, the first theoretical calculations for electron impact total and ionization cross section have been performed for most of the targets having numerous practical applications. A reasonable agreement is obtained compared to existing experimental observations for all the targets reported here, especially for the total cross section.

  20. Calculation of total and ionization cross sections for electron scattering by primary benzene compounds

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Suvam; Naghma, Rahla; Kaur, Jaspreet; Antony, Bobby, E-mail: bka.ism@gmail.com [Atomic and Molecular Physics Lab, Department of Applied Physics, Indian School of Mines, Dhanbad (India)

    2016-07-21

    The total and ionization cross sections for electron scattering by benzene, halobenzenes, toluene, aniline, and phenol are reported over a wide energy domain. The multi-scattering centre spherical complex optical potential method has been employed to find the total elastic and inelastic cross sections. The total ionization cross section is estimated from total inelastic cross section using the complex scattering potential-ionization contribution method. In the present article, the first theoretical calculations for electron impact total and ionization cross section have been performed for most of the targets having numerous practical applications. A reasonable agreement is obtained compared to existing experimental observations for all the targets reported here, especially for the total cross section.

  1. Preparation of transmission electron microscopy cross-section specimens using focused ion beam milling

    International Nuclear Information System (INIS)

    Langford, R.M.; Petford-Long, A.K.

    2001-01-01

    The preparation of transmission electron microscopy cross-section specimens using focused ion beam milling is outlined. The 'liftout' and 'trench' techniques are both described in detail, and their relative advantages and disadvantages are discussed. Artifacts such as ion damage to the top surface and sidewalls of the cross-section specimens, and methods of reducing them, are addressed

  2. Measurements of integral cross-sections of incoherent interactions of photons with L-shell electrons

    Energy Technology Data Exchange (ETDEWEB)

    Verma, S L; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1983-05-21

    Integral cross-sections of incoherent interactions of 662 and 1250 keV gamma-rays with L-shell electrons of different elements with 74<=Z<=92 have been measured. The experimental results, when interpreted in terms of photoelectric and Compton interaction cross-sections, are found to agree with theory.

  3. Total cross section of furfural by electron impact: Experiment and theory.

    Science.gov (United States)

    Traoré Dubuis, A; Verkhovtsev, A; Ellis-Gibbings, L; Krupa, K; Blanco, F; Jones, D B; Brunger, M J; García, G

    2017-08-07

    We present experimental total cross sections for electron scattering from furfural in the energy range from 10 to 1000 eV, as measured using a double electrostatic analyzer gas cell electron transmission experiment. These results are compared to theoretical data for furfural, as well as to experimental and theoretical values for the structurally similar molecules furan and tetrahydrofuran. The measured total cross section is in agreement with the theoretical results obtained by means of the independent-atom model with screening corrected additivity rule including interference method. In the region of higher electron energies, from 500 eV to 10 keV, the total electron scattering cross section is also estimated using a semi-empirical model based on the number of electrons and dipole polarizabilities of the molecular targets. Together with the recently measured differential and integral cross sections, and the furfural energy-loss spectra, the present total cross section data nearly complete the data set that is required for numerical simulation of low-energy electron processes in furfural, covering the range of projectile energies from a few electron volts up to 10 keV.

  4. Total cross section of furfural by electron impact: Experiment and theory

    Science.gov (United States)

    Traoré Dubuis, A.; Verkhovtsev, A.; Ellis-Gibbings, L.; Krupa, K.; Blanco, F.; Jones, D. B.; Brunger, M. J.; García, G.

    2017-08-01

    We present experimental total cross sections for electron scattering from furfural in the energy range from 10 to 1000 eV, as measured using a double electrostatic analyzer gas cell electron transmission experiment. These results are compared to theoretical data for furfural, as well as to experimental and theoretical values for the structurally similar molecules furan and tetrahydrofuran. The measured total cross section is in agreement with the theoretical results obtained by means of the independent-atom model with screening corrected additivity rule including interference method. In the region of higher electron energies, from 500 eV to 10 keV, the total electron scattering cross section is also estimated using a semi-empirical model based on the number of electrons and dipole polarizabilities of the molecular targets. Together with the recently measured differential and integral cross sections, and the furfural energy-loss spectra, the present total cross section data nearly complete the data set that is required for numerical simulation of low-energy electron processes in furfural, covering the range of projectile energies from a few electron volts up to 10 keV.

  5. Total electron scattering cross section from pyridine molecules in the energy range 10-1000 eV

    Science.gov (United States)

    Dubuis, A. Traoré; Costa, F.; da Silva, F. Ferreira; Limão-Vieira, P.; Oller, J. C.; Blanco, F.; García, G.

    2018-05-01

    We report on experimental total electron scattering cross-section (TCS) from pyridine (C5H5N) for incident electron energies between 10 and 1000 eV, with experimental uncertainties within 5-10%, as measured with a double electrostatic analyser apparatus. The experimental results are compared with our theoretical calculations performed within the independent atom model complemented with a screening corrected additivity rule (IAM-SCAR) procedure which has been updated by including interference effects. A good level of agreement is found between both data sources within the experimental uncertainties. The present TCS results for electron impact energy under study contribute, together with other scattering data available in the literature, to achieve a consistent set of cross section data for modelling purposes.

  6. The Hanle effect and level-crossing spectroscopy

    CERN Document Server

    Strumia, Franco

    1991-01-01

    I am most pleased and, in a way, I feel honored to write the Foreword for the book The Hanle Effect and Level-Crossing Spectroscopy, which covers such a very wide range of applications not only in the initial areas of atomic and molecular physics, but also in solid state physics, solar physics, laser physics, and gravitational metrology. To link these fields together in a coherent way has been the merit of the editors of the book, who attracted most distinguished authors for writing the chapters. In retrospect to Hanle's discovery of quantum mechanical coherence between two quantum states about 65 years ago, this book demonstrates the enormous impact and central importance the effect has had, and most vividly still has, on modern physics. On the other hand, the concept of quantum mechanical coherence, which is an outgrowth of the linear super­ position principle of quantum states, has been evident through a consider­ able number of experimental methods beyond the original Hanle effect; some of these methods...

  7. Predicting civil religion at a cross-cultural level

    Directory of Open Access Journals (Sweden)

    Lavrič Miran

    2009-01-01

    Full Text Available The concept of civil religion has caught major attention among scholars studying the junction of religion and politics (J.-J. Rousseau, E. Durkheim, R. Bellah. The notion focuses on the phenomenon of cultural contents sacralizing and ritualizing the ruling political institutions of a society, extending support to the integration of the political and social system at a cultural level. The notion of civil religion has recently been operationalized crossculturally, but light has not been shed upon its predictors. In this paper authoritarianism is tested as a predictor of civil religion cross-culturally. Four student samples of Bosnian, Serbian, Slovenian and US students were analyzed. Very strong, significant associations between authoritarianism, as operationalized by a modified Lane scale, and civil religion were found in all cases. Moreover, upon introducing femininity, anxiety and gender into the analysis, a strong, dominant and significant impact on the part of authoritarianism was still found when civil religion was observed crossculturally. When the same predictors were applied to explaining general religiosity, authoritarianism fell short of being a significant predictor in most of the environments observed. Such results suggest an especially close link between civil religion and authoritarianism.

  8. Adaptive Rate Sampling and Filtering Based on Level Crossing Sampling

    Directory of Open Access Journals (Sweden)

    Saeed Mian Qaisar

    2009-01-01

    Full Text Available The recent sophistications in areas of mobile systems and sensor networks demand more and more processing resources. In order to maintain the system autonomy, energy saving is becoming one of the most difficult industrial challenges, in mobile computing. Most of efforts to achieve this goal are focused on improving the embedded systems design and the battery technology, but very few studies target to exploit the input signal time-varying nature. This paper aims to achieve power efficiency by intelligently adapting the processing activity to the input signal local characteristics. It is done by completely rethinking the processing chain, by adopting a non conventional sampling scheme and adaptive rate filtering. The proposed approach, based on the LCSS (Level Crossing Sampling Scheme presents two filtering techniques, able to adapt their sampling rate and filter order by online analyzing the input signal variations. Indeed, the principle is to intelligently exploit the signal local characteristics—which is usually never considered—to filter only the relevant signal parts, by employing the relevant order filters. This idea leads towards a drastic gain in the computational efficiency and hence in the processing power when compared to the classical techniques.

  9. Pulsar kicks with modified Urca and electrons in Landau levels

    International Nuclear Information System (INIS)

    Henley, Ernest M.; Johnson, Mikkel B.; Kisslinger, Leonard S.

    2007-01-01

    We derive the energy asymmetry given the protoneutron star during the time when the neutrino sphere is near the surface of the protoneutron star, using the modified Urca process. The electrons produced with the antineutrinos are in Landau levels due to the strong magnetic field, and this leads to asymmetry in the neutrino momentum, and a pulsar kick. The magnetic field must be strong enough for a large fraction of the electrons to be in the lowest Landau level; however, there is no direct dependence of our pulsar velocity on the strength of the magnetic field. Our main prediction is that the large pulsar kicks start at about 10 s and last for about 10 s, with the corresponding neutrinos correlated with the direction of the magnetic field. We predict a pulsar velocity of 1.03x10 -4 (T/10 10 K) 7 km/s, which reaches 1000 km/s if T≅10 11 K

  10. Studies on deep electronic levels in silicon and aluminium gallium arsenide alloys

    International Nuclear Information System (INIS)

    Pettersson, H.

    1993-01-01

    This thesis reports on investigations of the electrical and optical properties of deep impurity centers, related to the transition metals (TMs) Ti, Mo, W, V and Ni, in silicon. Emission rates, capture cross sections and photoionization cross sections for these impurities were determined by means of various Junction Space Charge Techniques (JSCTs), such as Deep Level Transient Spectroscopy (DLTS), dark capacitance transient and photo capacitance transient techniques. Changes in Gibbs free energy as a function of temperature were calculated for all levels. From this temperature dependence, the changes in enthalpy and entropy involved in the electron and hole transitions were deduced. The influence of high electric fields on the electronic levels in chalcogen-doped silicon were investigated using the dark capacitance transient technique. The enhancement of the electron emission from the deep centers indicated a more complex field enhancement model than the expected Poole-Frenkel effect for coulombic potentials. The possibility to determine charge states of defects using the Poole-Frenkel effect, as often suggested, is therefore questioned. The observation of a persistent decrease of the dark conductivity due to illumination in simplified AlGaAs/GaAs high Electron Mobility Transistors (HEMTs) over the temperature range 170K< T<300K is reported. A model for this peculiar behavior, based on the recombination of electrons in the two-dimensional electron gas (2DEG) located at the AlGaAs/GaAs interface with holes generated by a two-step excitation process via the deep EL2 center in the GaAs epilayer, is put forward

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

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  12. Tin-vacancy acceptor levels in electron-irradiated n-type silicon

    DEFF Research Database (Denmark)

    Larsen, A. Nylandsted; Goubet, J. J.; Mejlholm, P.

    2000-01-01

    Si crystals (n-type, fz) with doping levels between 1.5x10(14) and 2x10(16)cm(-3) containing in addition similar to 10(18) Sn/cm(3) were irradiated with 2-MeV electrons to different doses and subsequently studied by deep level transient spectroscopy, Mossbauer spectroscopy, and positron...... annihilation. Two tin-vacancy (Sn-V) levels at E-c - 0.214 eV and E-c - 0.501 eV have been identified (E-c denotes the conduction band edge). Based on investigations of the temperature dependence of the electron-capture cross sections, the electric-field dependence of the electron emissivity, the anneal...... temperature, and the defect-introduction rate, it is concluded that these levels are the double and single acceptor levels, respectively, of the Sn-V pair. These conclusions are in agreement with electronic structure calculations carried out using a local spin-density functional theory, incorporating...

  13. New approximations of the differential electron-atom elastic scattering cross-sections

    International Nuclear Information System (INIS)

    Niculescu, V.I.R.; Catana, D.

    1994-01-01

    In the present note concerning the electron-atom interaction a cubic Spline method was used to obtain approximations of the differential cross-sections. These approximations gave a 20 times reduction of the computing time preserving also the accuracy (2%). The example is for Al in the 1-256 keV electron energy range. (Author) 2 Tabs., 3 Refs

  14. Effective source of bremsstrahlung with multiple crossing of a thin target by an electron beam

    International Nuclear Information System (INIS)

    Grishin, V.K.; Ishkhanov, B.S.; Shvedunov, V.I.

    1996-01-01

    A basically new scheme of electron beam discharge to the target for x ray and gamma radiation generation is proposed. In this case an accelerated electron beam crosses a thin braking target many times, which substantially increases the integral radiation yield. 3 refs.; 2 figs

  15. Prediction for neutrino-electron cross-sections in Weinberg's model for weak interactions

    NARCIS (Netherlands)

    Hooft, G. 't

    1971-01-01

    Weinberg's theory of purely leptonic weak interactions can be tested in neutrino-electron scattering experiments. Cross-sections must be measured as a function of the energy of the recoil electron. If Weinberg's theory is correct, then the masses of the intermediate vector bosons can be derived from

  16. Plasma-screening effects upon energy levels and electron scattering from neutral and ionized caesium

    International Nuclear Information System (INIS)

    Chin, Y.J.; Radtke, R.; Zimmermann, R.

    1988-01-01

    Using interaction potentials screened with the Debye-Hueckel length, the effects of plasma shielding on energy levels and electrons scattering from neutral and ionized caesium are estimated. Both energy levels and atomic scattering cross-sections are found to be sensitive to the inclusion of screening. Relating to the scattering by the Cs + ion, a low-energy resonance near E = 0.3 Ryd is found which arises from the f-wave phase shift and reflects the individual behaviour of the scattering ion. (author)

  17. Plasma-screening effects upon energy levels and electron scattering from neutral and ionized caesium

    Energy Technology Data Exchange (ETDEWEB)

    Chin, Y J; Radtke, R; Zimmermann, R

    1988-01-01

    Using interaction potentials screened with the Debye-Hueckel length, the effects of plasma shielding on energy levels and electrons scattering from neutral and ionized caesium are estimated. Both energy levels and atomic scattering cross-sections are found to be sensitive to the inclusion of screening. Relating to the scattering by the Cs/sup +/ ion, a low-energy resonance near E = 0.3 Ryd is found which arises from the f-wave phase shift and reflects the individual behaviour of the scattering ion.

  18. Measurement of the Charged-Current Quasi-Elastic Cross-Section for Electron Neutrinos on a Hydrocarbon Target

    Energy Technology Data Exchange (ETDEWEB)

    Wolcott, Jeremy [Univ. of Rochester, NY (United States)

    2016-01-01

    Appearance-type neutrino oscillation experiments, which observe the transition from muon neutrinos to electron neutrinos, promise to help answer some of the fundamental questions surrounding physics in the post-Standard-Model era. Because they wish to observe the interactions of electron neutrinos in their detectors, and because the power of current results is typically limited by their systematic uncertainties, these experiments require precise estimates of the cross-section for electron neutrino interactions. Of particular interest is the charged-current quasi-elastic (CCQE) process, which gures signi cantly in the composition of the reactions observed at the far detector. However, no experimental measurements of this crosssection currently exist for electron neutrinos; instead, current experiments typically work from the abundance of muon neutrino CCQE cross-section data and apply corrections from theoretical arguments to obtain a prediction for electron neutrinos. Veri cation of these predictions is challenging due to the di culty of constructing an electron neutrino beam, but the advent of modern high-intensity muon neutrino beams|together with the percent-level electron neutrino impurity inherent in these beams| nally presents the opportunity to make such a measurement. We report herein the rst-ever measurement of a cross-section for an exclusive state in electron neutrino scattering, which was made using the MINER A detector in the NuMI neutrino beam at Fermilab. We present the electron neutrino CCQE di erential cross-sections, which are averaged over neutrinos of energies 1-10 GeV (with mean energy of about 3 GeV), in terms of various kinematic variables: nal-state electron angle, nal-state electron energy, and the square of the fourmomentum transferred to the nucleus by the neutrino , Q2. We also provide a total cross-section vs. neutrino energy. While our measurement of this process is found to be in agreement with the predictions of the GENIE

  19. Resonant ion-pair formation in the recombination of NO+ with electrons: Cross-section determination

    International Nuclear Information System (INIS)

    Le Padellec, A.; Djuric, N.; Al-Khalili, A.; Danared, H.; Derkatch, A. M.; Neau, A.; Popovic, D. B.; Rosen, S.; Semaniak, J.; Thomas, R.

    2001-01-01

    Resonant ion-pair formation from the collisions of NO + ions with electrons was studied using the heavy-ion storage ring CRYRING at the Manne Siegbahn Laboratory of Stockholm University. The total cross section is measured for the formation of N + +O - for electron energies 8--18 eV, and the results are compared with ion-pair formation in photoionization work. A peak in the cross section is observed at 12.5 eV, with a magnitude of 8.5 x 10 -19 cm 2 . An attempt to extract the cross section for the reverse process of associative ionization is made

  20. Single electron attachment and stripping cross sections for relativistic heavy ions

    International Nuclear Information System (INIS)

    Crawford, H.J.

    1979-06-01

    The results of a Bevalac experiment to measure the single electron attachment and stripping cross sections for relativistic (0.5 1 , and fully stripped, N 0 , ion beams emerging from the targets. Separate counters measured the number of ions in each charge state. The ratios N 1 /N 0 for different target thicknesses were fit to a simple growth curve to yield electron attachment and stripping cross sections. The data are compared to relativistic extrapolations of available theories. Clear evidence for two separate attachment processes, radiative and non-radiative, is found. Data are compared to a recently improved formulation for the stripping cross sections

  1. Electron impact excitation out of the 23S metastable level of He

    International Nuclear Information System (INIS)

    Boffard, J.B.; Piech, G.A.; Lagus, M.E.; Anderson, L.W.; Chun C.L.

    1996-01-01

    Using a hollow cathode discharge as a source of He, the authors have measured absolute cross sections for electron excitation out of the 2S level of He into the n=2, 3, 4, and 5 triplet levels for energies up to 20 eV. Their results show a pattern of sharply peaked excitation functions into the n = 3, 4, and 5 3 S and 3 P levels, and comparatively broad excitation functions into the 3 D levels. The 2 3 P level has a remarkably broad excitation function, and its peak direct cross section is over 10 times the size of the next largest peak cross section observed. For energies above 20 eV, the authors use charge exchange of a fast He + beam with cesium to produce a primarily He target. This allows them to extend their measurements for selected triplet levels out to 1 keV. Their data indicate that even at this energy the excitations into the 3 3 S, 3 3 D, 4 3 D have not yet entered the Born regime. Comparisons with other theoretical calculations at low energies will be made

  2. Density and field effect on electron-ion collision cross-sections in hot dense plasma

    International Nuclear Information System (INIS)

    Gaufridy de Dortan, F. de

    2003-03-01

    Collisional excitation cross-sections are essential for the modeling of the properties of non equilibrium plasmas. There has been a lot of work on electron impact excitation of isolated ions, but in dense plasmas, neighboring particles are expected to widely disturb these electron transitions in atoms. Plasma modeling through a radially perturbed potential has already been done but is not satisfactory as it does not account for levels degeneracy breaking and its consequences. Introduction of a quasistatic electric micro-field of neighboring ions allows us to break spherical symmetry. Our original theoretical study has given birth to a numerical code that accurately computes collisional strengths and rates (in the Distorted Waves approach) in atoms submitted to a realistic micro-field. Hydrogen- and helium-like aluminium is studied. Stark mixing widely increases rates of transitions from high l levels and forbidden transitions are field-enhanced by many orders of magnitude until they reach allowed ones. Eventually, we conduct an elementary stationary collisional radiative study to investigate field-enhancement effects on corresponding line shapes. In cases we study (aluminium, hydrogen- and helium-like) we find a relatively weak increase of K-shell line broadening

  3. Energy and angle differential cross sections for the electron-impact double ionization of helium

    International Nuclear Information System (INIS)

    Colgan, James P.; Pindzola, M.S.; Robicheaux, F.

    2008-01-01

    Energy and angle differential cross sections for the electron-impact double ionization of helium are calculated using a non-perturbative time-dependent close-coupling method. Collision probabilities are found by projection of a time evolved nine dimensional coordinate space wave function onto fully antisymmetric products of spatial and spin functions representing three outgoing Coulomb waves. At an incident energy of 106 eV, we present double energy differential cross sections and pentuple energy and angle differential cross sections. The pentuple energy and angle differential cross sections are found to be in relative agreement with the shapes observed in recent (e,3e) reaction microscope experiments. Integration of the differential cross sections over all energies and angles yields a total ionization cross section that is also in reasonable agreement with absolute crossed-beams experiments.

  4. Mechanisms of molecular electronic rectification through electronic levels with strong vibrational coupling

    DEFF Research Database (Denmark)

    Kuznetsov, A.M.; Ulstrup, Jens

    2002-01-01

    We present a new view and an analytical formalism of electron flow through a donor-acceptor molecule inserted between a pair of metal electrodes. The donor and acceptor levels are strongly coupled to an environmental nuclear continuum. The formalism applies to molecular donor-acceptor systems bot...

  5. To calculation of electron-optical characteristics of crossed lenses

    International Nuclear Information System (INIS)

    Afanas'ev, V.P.; Gritsyuk, N.P.; Lachashvili, R.A.; Yavor, S.Ya.

    1979-01-01

    Two approaches are used for theoretical study of crossed lenses (CL), which are formed by plates with slits turned by 90 deg: 1) aberration determination according to axial determination of potential and 2) trajectory analysis of CL. While studying CL of definite configuration it is necessary to take into account aberrations of the highest order. The following conclusions are drawn: the classical method is applied for fast determination of the main characteristics, of CL by means of average power computers (the ''M-220'' or the ''Minsk-32'' computers); the trajectory analysis should be performed by means of power computer (the BESM-6) when it is necessary to obtain more detailed information of the CL, including the trajectory deflection along the system axis, the dimensions of the point source image taking into account the aberrations of the highest order

  6. Measurements of Neutron Induced Cross Sections at the Oak Ridge Electron Linear Accelerator

    International Nuclear Information System (INIS)

    Guber, K.H.; Harvey, J.A.; Hill, N.W.; Koehler, P.E.; Leal, L.C.; Sayer, R.O.; Spencer, R.R.

    1999-01-01

    We have used the Oak Ridge Electron Linear Accelerator (ORELA) to measure neutron total and the fission cross sections of 233 U in the energy range from 0.36 eV to 700 keV. We report average fission and total cross sections. Also, we measured the neutron total cross sections of 27 Al and Natural chlorine as well as the capture cross section of Al over an energy range from 100 eV up to about 400 keV

  7. Nicotine and Cotinine Levels With Electronic Cigarette: A Review.

    Science.gov (United States)

    Marsot, A; Simon, N

    2016-01-01

    Since their introduction in 2004, electronic cigarettes (e-cigarettes) have gained popularity worldwide. E-cigarettes are marketed as nicotine delivery devices. Commonly reported reasons for use include to quit smoking, to reduce urge to smoke, or the perceived lower risk alternative to smoking. But what are the actual amounts of nicotine delivered? This review summarizes all the published studies concerning nicotine or cotinine levels following e-cigarette use. A literature search was conducted from the PubMed database, from 1985 to January 2014, using the following terms: electronic cigarette(s), e-cigarette(s), electronic nicotine delivery system, cotinine, and nicotine. Articles were excluded if they were not pertinent according to our criteria. References of all relevant articles were also evaluated. Eight studies were included in this review. The following information was extracted from the articles: population size, age of participants, recruitment, inclusion and exclusion criteria, concentration of nicotine in refills liquids, study sample design, and observed concentrations. Following design of studies, plasma nicotine Cmax was observed between 0 and 5 ng/mL (no significant changes) or between 13.9 and 16.3 ng/mL (similar to a tobacco cigarette) with a Tmax between 70 and 75 minutes. Cotinine levels after "vaping" an e-cigarette are similar to a tobacco cigarette. This review summarizes e-cigarette studies that contain information on nicotine or cotinine levels. The peak concentration of nicotine appears to be dependent on the use and dose level of e-cigarette cartridge. The value of this peak concentration is similar to the value found with a tobacco cigarette. However, the time corresponding to the peak concentration is delayed compared to a tobacco cigarette. © The Author(s) 2015.

  8. Total and elastic electron scattering cross sections from Xe at intermediate and high energies

    International Nuclear Information System (INIS)

    Garcia, G; Pablos, J L de; Blanco, F; Williart, A

    2002-01-01

    Experimental total electron scattering cross sections from Xe in the energy range 300-5000 eV have been obtained with experimental errors of about 3%. The method was based on the measurement of the attenuation of a linear electron beam through a Xe gas cell in combination with an electron spectroscopy technique to analyse the energy of the transmitted electrons. Differential and integral elastic cross sections have been calculated using a scattering potential method which includes relativistic effects. The consistency of our theoretical and experimental results is also discussed in the paper. Finally, analytical formulae depending on two parameters, namely the number of target electrons and the atomic polarizability, are given to reproduce the experimental data for Ne, Ar, Kr and Xe in the energy range 500-10 000 eV

  9. Cross section for electronic energy transfer between mercury isotopes

    International Nuclear Information System (INIS)

    Lagushenko, R.; Grossman, M.W.; Maya, J.

    1984-01-01

    Previous estimates of the cross section (sigma) for the process 1 Hg(6 3 P 1 )+ /sup J/ Hg(6 1 S /sub o/ )→ 1 Hg(6 1 S /sub o/ )+ /sup J/ Hg(6 3 P 1 ), where i and j are any one of the six stable Hg isotopes, are no better than a factor of ten. We have recently measured the hyperfine structure of the 253.7nm Hg resonance line in low pressure Hg-Ar discharge for natural Hg as well as Hg enriched in 196 Hg by 2-4%, as a function of temperature. Using our previously developed resonance radiation transport model in a low pressure Hg+Ar plasma we calculated the exact shape of the hyperfine structure and found a high degree of sensitivity to the value of (sigma). By varying (sigma) we were able to obtain a best fit to the measured hyperfine structure as a function of temperature. This fit determined the value of (sigma). We believe the accuracy of this determination is about 30%

  10. Relativistic total and differential cross section proton--proton electron--positron pair production calculation

    International Nuclear Information System (INIS)

    Rubinstein, J.E.

    1976-01-01

    Circle Feynman diagrams for a specific permutation of variables along with their corresponding algebraic expressions are presented to evaluate [H] 2 for proton-proton electron-positron pair production. A Monte Carlo integration technique is introduced and is used to set up the multiple integral expression for the total pair production cross section. The technique is first applied to the Compton scattering problem and then to an arbitrary multiple integral. The relativistic total cross section for proton-proton electron-positron pair production was calculated for eight different values of incident proton energy. A variety of differential cross sections were calculated for the above energies. Angular differential cross section distributions are presented for the electron, positron, and proton. Invariant mass differential cross section distributions are done both with and without the presence of [H] 2 . Both WGHT and log 10 (TOTAL) distributions were also obtained. The general behavioral trends of the total and differential cross sections for proton-proton electron-positron pair production are presented. The range of validity for this calculation is from 0 to about 200 MeV

  11. Differential cross sections for intermediate-energy electron scattering from α-tetrahydrofurfuryl alcohol: Excitation of electronic-states

    Energy Technology Data Exchange (ETDEWEB)

    Chiari, L.; Jones, D. B.; Thorn, P. A.; Pettifer, Z. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Silva, G. B. da [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Limão-Vieira, P. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Duflot, D. [Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, Université Lille, F-59655 Villeneuve d’Ascq Cedex (France); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Université de Liège, Institut de Chimie-Bât. B6C, B-4000 Liège 1 (Belgium); Blanco, F. [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040 (Spain); García, G. [Instituto de Física Fundamental, CSIC, Madrid E-28006 (Spain); and others

    2014-07-14

    We report on measurements of differential cross sections (DCSs) for electron impact excitation of a series of Rydberg electronic-states in α-tetrahydrofurfuryl alcohol (THFA). The energy range of these experiments was 20–50 eV, while the scattered electron was detected in the 10°–90° angular range. There are currently no other experimental data or theoretical computations against which we can directly compare the present measured results. Nonetheless, we are able to compare our THFA DCSs with earlier cross section measurements for Rydberg-state electronic excitation for tetrahydrofuran, a similar cyclic ether, from Do et al. [J. Chem. Phys. 134, 144302 (2011)]. In addition, “rotationally averaged” elastic DCSs, calculated using our independent atom model with screened additivity rule correction approach are also reported. Those latter results give integral cross sections consistent with the optical theorem, and supercede those from the only previous study of Milosavljević et al. [Eur. Phys. J. D 40, 107 (2006)].

  12. Measurements of secondary electron cross sections by the pulsed electron beam time-of-flight method. I. Molecular nitrogen

    International Nuclear Information System (INIS)

    Goruganthu, R.R.; Wilson, W.G.; Bonham, R.A.

    1983-01-01

    The secondary electron cross sections for gaseous molecular nitrogen are reported at ejection angles of 30, 45, 60, 75, 90, 105, 120, 135 and 150 0 , for the energy range 1.5 eV to 20 eV and incident electron energy of 1 keV. The pulsed electron beam time-of-flight methd was employed. The results were placed on an absolute scale by normalization to the elastic scattering. They were compared, where possible, with those reported by Opal, Beaty, and Peterson (OBP). The agreement is somewhat better when the OBP data are divided by 0.53 + 0.47 sintheta as suggested by Rudd and DuBois. Fits of our data by Legendre-polynomial expansions are used to estimate the low-energy portion of the cross-section, dsigma/dE. This work suggests that existing experimental cross sections for secondary electron ejection as a function of angle and ejected energy may be no better known than +-40%, especially in the low energy region. 7 references, 14 figures, 2 tables

  13. The role of secondary electrons in some experiments determining fluorescence emission from nitrogen C3Πu levels

    International Nuclear Information System (INIS)

    Blanco, F.; Arqueros, F.

    2005-01-01

    The processes involved in fluorescence emission from C 3 Π u levels of N 2 molecule by electron impact are studied. Secondary electrons are shown to play an important role in typical experiments for the measurement of emission cross sections and fluorescence yields, dominating at high impact energies. A simple model is proposed which accounts for fluorescence measurements in a wide range of experimental conditions, and in particular for some recent results up to 1 GeV energies

  14. Electronic Health Record Portal Adoption: a cross country analysis.

    Science.gov (United States)

    Tavares, Jorge; Oliveira, Tiago

    2017-07-05

    This study's goal is to understand the factors that drive individuals to adopt Electronic Health Record (EHR) portals and to estimate if there are differences between countries with different healthcare models. We applied a new adoption model using as a starting point the extended Unified Theory of Acceptance and Use of Technology (UTAUT2) by incorporating the Concern for Information Privacy (CFIP) framework. To evaluate the research model we used the partial least squares (PLS) - structural equation modelling (SEM) approach. An online questionnaire was administrated in the United States (US) and Europe (Portugal). We collected 597 valid responses. The statistically significant factors of behavioural intention are performance expectancy ([Formula: see text] total  = 0.285; P expectancy ([Formula: see text] total  = 0.160; P value ([Formula: see text] total  = 0.152; P value are only predictors in the US group. The model explained 53% of the variance in behavioural intention and 36% of the variance in use behaviour. Our study identified critical factors for the adoption of EHR portals and significant differences between the countries. Confidentiality issues do not seem to influence acceptance. The EHR portals usage patterns are significantly higher in US compared to Portugal.

  15. Cross sections and spin polarizations of electrons elastically scattered from oriented molecules (CH3I)

    International Nuclear Information System (INIS)

    Fink, M.; Ross, A.W.; Fink, R.J.

    1989-01-01

    Elastic differential cross sections and spin polarizations for electrons elastically scattered from CH 3 I are calculated using the independent atom model. Three molecular orientations with respect to the incident electron wavevector are considered - first, the molecule is oriented randomly, second, the electron wave front and molecular bond are parallel, and third, the wavefront and the bond axis are perpendicular. It will be seen to what extent orientational averaging weakens features of the cross section and spin polarization. The calculations show that cross section and spin polarization measurements are a possible tool for determining the degree of molecular orientation. There is no degeneracy between I-C and C-I in cross section and spin polarization measurements. The results presented here for 200 eV and 600 eV electrons scattered by CH 3 I should be considered as a case study and it should be possible to find molecules and electron energies for which even more dramatic differences between the various orientations between the molecules and the electrons can be expected. (orig.)

  16. Differential cross sections for electron-impact vibrational-excitation of tetrahydrofuran at intermediate impact energies

    Energy Technology Data Exchange (ETDEWEB)

    Do, T. P. T. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); School of Education, Can Tho University, Campus II, 3/2 Street, Xuan Khanh, Ninh Kieu, Can Tho City (Viet Nam); Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Konovalov, D. A.; White, R. D. [College of Science, Technology and Engineering, James Cook University, Townsville (Australia); Brunger, M. J., E-mail: michael.brunger@flinders.edu.au, E-mail: darryl.jones@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Jones, D. B., E-mail: michael.brunger@flinders.edu.au, E-mail: darryl.jones@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia)

    2015-03-28

    We report differential cross sections (DCSs) for electron-impact vibrational-excitation of tetrahydrofuran, at intermediate incident electron energies (15-50 eV) and over the 10°-90° scattered electron angular range. These measurements extend the available DCS data for vibrational excitation for this species, which have previously been obtained at lower incident electron energies (≤20 eV). Where possible, our data are compared to the earlier measurements in the overlapping energy ranges. Here, quite good agreement was generally observed where the measurements overlapped.

  17. Component-Level Electronic-Assembly Repair (CLEAR) System Architecture

    Science.gov (United States)

    Oeftering, Richard C.; Bradish, Martin A.; Juergens, Jeffrey R.; Lewis, Michael J.; Vrnak, Daniel R.

    2011-01-01

    This document captures the system architecture for a Component-Level Electronic-Assembly Repair (CLEAR) capability needed for electronics maintenance and repair of the Constellation Program (CxP). CLEAR is intended to improve flight system supportability and reduce the mass of spares required to maintain the electronics of human rated spacecraft on long duration missions. By necessity it allows the crew to make repairs that would otherwise be performed by Earth based repair depots. Because of practical knowledge and skill limitations of small spaceflight crews they must be augmented by Earth based support crews and automated repair equipment. This system architecture covers the complete system from ground-user to flight hardware and flight crew and defines an Earth segment and a Space segment. The Earth Segment involves database management, operational planning, and remote equipment programming and validation processes. The Space Segment involves the automated diagnostic, test and repair equipment required for a complete repair process. This document defines three major subsystems including, tele-operations that links the flight hardware to ground support, highly reconfigurable diagnostics and test instruments, and a CLEAR Repair Apparatus that automates the physical repair process.

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

    International Nuclear Information System (INIS)

    Borovik, A; Roman, V; Kupliauskienė, A

    2012-01-01

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

  19. Intermediate-level crossings of a first-passage path

    International Nuclear Information System (INIS)

    Bhat, Uttam; Redner, S

    2015-01-01

    We investigate some simple and surprising properties of a one-dimensional Brownian trajectory with diffusion coefficient D that starts at the origin and: (i) is at X at time T, or (ii) first reaches X at time T. We determine the most likely location of the first-passage trajectory from (0, 0) to (X, T) and its distribution at any intermediate time t < T. A first-passage path typically starts out by being repelled from its final location when X 2 /DT ≪ 1. We also determine the distribution of times when the trajectory first crosses and last crosses an arbitrary intermediate position x < X. The distribution of first-crossing times may be unimodal or bimodal, depending on whether X 2 /DT ≪ 1 or X 2 /DT ≫ 1. The form of the first-crossing probability in the bimodal regime is qualitatively similar to, but more singular than, the well-known arcsine law. (paper)

  20. Component-Level Electronic-Assembly Repair (CLEAR) Operational Concept

    Science.gov (United States)

    Oeftering, Richard C.; Bradish, Martin A.; Juergens, Jeffrey R.; Lewis, Michael J.; Vrnak, Daniel R.

    2011-01-01

    This Component-Level Electronic-Assembly Repair (CLEAR) Operational Concept document was developed as a first step in developing the Component-Level Electronic-Assembly Repair (CLEAR) System Architecture (NASA/TM-2011-216956). The CLEAR operational concept defines how the system will be used by the Constellation Program and what needs it meets. The document creates scenarios for major elements of the CLEAR architecture. These scenarios are generic enough to apply to near-Earth, Moon, and Mars missions. The CLEAR operational concept involves basic assumptions about the overall program architecture and interactions with the CLEAR system architecture. The assumptions include spacecraft and operational constraints for near-Earth orbit, Moon, and Mars missions. This document addresses an incremental development strategy where capabilities evolve over time, but it is structured to prevent obsolescence. The approach minimizes flight hardware by exploiting Internet-like telecommunications that enables CLEAR capabilities to remain on Earth and to be uplinked as needed. To minimize crew time and operational cost, CLEAR exploits offline development and validation to support online teleoperations. Operational concept scenarios are developed for diagnostics, repair, and functional test operations. Many of the supporting functions defined in these operational scenarios are further defined as technologies in NASA/TM-2011-216956.

  1. A semi-empirical formula for total cross sections of electron scattering from diatomic molecules

    International Nuclear Information System (INIS)

    Liu Yufang; Sun Jinfeng; Henan Normal Univ., Xinxiang

    1996-01-01

    A fitting formula based on the Born approximation is used to fit the total cross sections for electron scattering by diatomic molecules (CO, N 2 , NO, O 2 and HCl) in the intermediate- and high-energy range. By analyzing the fitted parameters and the total cross sections, we found that the internuclear distance of the constituent atoms plays an important role in the e-diatomic molecule collision process. Thus a new semi-empirical formula has been obtained. There is no free parameter in the formula, and the dependence of the total cross sections on the internuclear distance has been reflected clearly. The total cross sections for electron scattering by CO, N 2 , NO, O 2 and HCl have been calculated over an incident energy range of 10-4000 eV. The results agree well with other available experimental and calculation data. (orig.)

  2. Empirical regularities in the excitation cross-section behavior of the lead atom (transitions from energy levels of 6pnd configurations)

    Science.gov (United States)

    Smirnov, Yu M.

    2018-03-01

    Electron-impact excitation of lead atom levels belonging to 6pnd configurations has been studied in experiment. One hundred two excitation cross-sections have been measured at an incident electron energy of 50 eV. Eleven optical excitation functions (OEFs) have been recorded in the exciting electron energy range of E = 0-200 eV. The resulting findings were used to study the excitation cross-sections dependence on the principal quantum number of upper levels for thirteen PbI spectral series.

  3. Uncertainties of Electron Capture Cross Sections In Be4+ + H(1s) Collisions

    International Nuclear Information System (INIS)

    Méndez, L.; Illescas, Clara; Jorge, Alba; Errea, L.F.; Rabadán, I.; Suárez, J.

    2014-01-01

    We have considered one-electron systems where the theoretical methods are well established. The use of different computational alternatives enables the accurate evaluation of nl-partial cross sections in a wide range of collision energies. In the presentation we have analyzed the uncertainties of n-partial charge exchange (CX) cross sections in Be 4+ + H(1s) collisions, which are relevant in tokamak plasmas and experimental data are not available.

  4. High-frequency two-electron photoionization cross section of triplet states

    International Nuclear Information System (INIS)

    Krivec, R.; Amusia, M.Ya.; Mandelzweig, V.B.

    2003-01-01

    Using high precision wave functions describing the triplet ground and excited 3 S states of the He atom and heliumlike ions, the cross sections of single- and double-electron photoionization are calculated. The dependence of the ratio R of the double and single ionization cross sections on the nuclear charge Z and the principal quantum number of excitation n is studied. The results obtained are compared to those for previously studied singlet states

  5. Bibliography of low energy electron and photon cross section data (through December 1974). Final report

    International Nuclear Information System (INIS)

    Kieffer, L.J.

    1976-03-01

    A bibliography of original reports of measurements or calculations of electron, positron and photon cross sections and their ions is presented. A detailed index to the bibliography allows retrieval of cross section data for specific processes and atomic or molecular species. A comprehensive author index is included. The bibliography covers the period 1921 through calendar year 1974, but some references late in 1974 may not have been found and included. No references were found prior to 1921

  6. Bibliography of low energy electron and photon cross section data. Report for Jan 1975-Dec 1977

    International Nuclear Information System (INIS)

    Gallagher, J.W.; Rumble, J.R. Jr; Beaty, E.C.

    1979-06-01

    A bibliography of original reports of measurements or calculations of electron, positron, and photon cross sections for atoms, small molecules, and their ions is presented. A detailed index to the bibliography facilitates retrieval of cross section data for specific processes and associated atomic or molecular species. A comprehensive author index is included. The bibliography covers the calendar years 1975-1977. This work supplements a previous bibliography which covered the literature through 1974

  7. Cross-Border Electronic Commerce: Distance Effects and Express Delivery in European Union Markets

    OpenAIRE

    Kim, Thai Young; Dekker, Rommert; Heij, Christiaan

    2017-01-01

    textabstractThis empirical study examines distance effects on cross-border electronic commerce and in particular the importance of express delivery in reducing the time dimension of distance. E-commerce provides suppliers with a range of opportunities to reduce distance as perceived by online buyers. They can reduce psychological barriers to cross-border demand by designing websites that simplify the search for and comparison of products and suppliers across countries. They can reduce cost ba...

  8. Theoretical and experimental study on electron interactions with chlorobenzene: Shape resonances and differential cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Alessandra Souza [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Varella, Márcio T. do N. [Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, SP (Brazil); Sanchez, Sergio d’A.; Bettega, Márcio H. F., E-mail: bettega@fisica.ufpr.br [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Ameixa, João; Limão-Vieira, Paulo; Ferreira da Silva, Filipe [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Blanco, Francisco [Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); and others

    2016-08-28

    In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in the high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7{sup ∘} to 110{sup ∘}. From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene.

  9. Differential cross sections for single-electron capture in He{sup 2+}-D collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, D.; Dagnac, R. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France)]|[Toulouse-3 Univ., 31 (France)

    1995-06-14

    A translational energy spectroscopy technique was used to study single-electron capture into the He{sup +} (n = 2) and He{sup +} (n 3) states in He{sup 2+}-D collisions. Differential cross sections were determined at 4, 6 and 8 keV in the angular range 5`-1{sup o}30` (laboratory frame). As expected, single-electron capture into the n = 2 state was found to be the dominant process; total cross sections for capture into the He{sup +} (n = 3) state were compared to other experimental and theoretical results. (author).

  10. Ionization of molecules by electron impact: Differential and total cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Rezkallah, Z. [Laboratoire de Physique Quantique et Systemes Dynamiques, Departement de physique, Faculte des sciences, Universite Ferhat Abbas, Setif 19000 (Algeria); Houamer, S., E-mail: hosalim@yahoo.com [Laboratoire de Physique Quantique et Systemes Dynamiques, Departement de physique, Faculte des sciences, Universite Ferhat Abbas, Setif 19000 (Algeria); Dal Cappello, C. [Laboratoire de Physique Moleculaire et des Collisions, Universite Paul Verlaine-Metz, Institut de Physique, 1 Boulevard Arago, 57078 Metz Cedex 3 (France); Charpentier, I. [Laboratoire de Physique et Mecanique des Materiaux, Universite Paul Verlaine-Metz UMR 7554, ile du Saulcy, 57045 Metz Cedex 1 (France); Roy, A.C. [School of Mathematical Sciences, Ramakrishna Mission Vivekananda University, Belur Math 711202, West Bengal (India)

    2011-12-01

    The first Born approximation is applied to calculate differential and total ionization cross sections of a set of small molecules, namely, HF, H{sub 2}O, NH{sub 3} and CH{sub 4} by electron impact. The molecular targets are described by single center molecular orbitals consisting of linear combinations of atomic orbitals (MO-LCAO). First, we have considered electron momentum spectroscopy experiments to check the accuracy of the wave functions. The triply, doubly, singly differential and total cross sections are then evaluated in a systematic way for a variety of kinematics. The results are discussed and compared with experiments.

  11. Urinary cotinine levels of electronic cigarette (e-cigarette) users.

    Science.gov (United States)

    Göney, Gülşen; Çok, İsmet; Tamer, Uğur; Burgaz, Sema; Şengezer, Tijen

    2016-07-01

    The popularity of electronic cigarettes (e-cigarettes) is rapidly increasing in many countries. These devices are designed to imitate regular cigarettes, delivering nicotine via inhalation without combusting tobacco but currently, there is a lack of scientific evidence on the presence or absence of nicotine exposure. Such research relies on evidence from e-cigarette users urine samples. In this study, we aimed to determine the levels and compare the amount of nicotine to which e-cigarette users, cigarette smokers and passive smokers are exposed. Therefore, urine samples were collected from e-cigarette users, cigarette smokers, passive smokers, and healthy nonsmokers. The urinary cotinine levels of the subjects were determined using gas chromatography-mass spectrometry. The mean (±SD) urinary cotinine levels were determined as 1755 ± 1848 ng/g creatinine for 32 e-cigarette users, 1720 ± 1335 ng/g creatinine for 33 cigarette smokers and 81.42 ± 97.90 ng/g creatinine for 33 passive smokers. A significant difference has been found between cotinine levels of e-cigarette users and passive smokers (p e-cigarette users and cigarette smokers (p > 0.05). This is a seminal study to demonstrate the e-cigarette users are exposed to nicotine as much as cigarette smokers.

  12. Polyelectrolytes processing at pilot scale level by electron beam irradiation

    International Nuclear Information System (INIS)

    Martin, D.; Cirstea, E.; Craciun, G.; Ighigeanu, D.; Marin, Gheorghe G.

    2002-01-01

    Three years of research, combined with engineering activities, have culminated in the development of a new method of electron beam processing applicable up to the pilot scale level, namely, the polyelectrolytes (acrylamide - acrylic acid copolymers) electron beam processing. This new radiation processing method has been achieved by bilateral co-operation between the National Institute for Laser, Plasma and Radiation Physics (NILPRP) and the Electrical Design and Research Institute, EDRI - Bucharest. The polyelectrolytes electron beam (EB) processing was put in operation at EDRI, where, recently, an industrial electron accelerator of 2 MeV and 20 kW, manufactured by Institute of Nuclear Physics, Novosibirsk, Russia was installed in a specially designed irradiation facility. Automatic start-up via computer control makes it compatible with industrial processing. According to the first conclusions, which resulted from our experimental research with regard to acrylamide - acrylic acid copolymers production by EB irradiation, the proper physical and chemical characteristics can be well controlled by chemical composition to be treated and by suitable adjustment of absorbed dose and absorbed dose rate. So, it was possible to obtain a very large area of characteristics and therefore a large area of applications. The conversion coefficient is very high (> 98%) and concentration of the residual monomer is under 0.05%. The tests applied to some wastewaters from the vegetable oil plants demonstrated that the fatty substances, matters in suspension, chemical oxygen demand and biological oxygen demand over 5 days were much reduced, in comparison with classical treatment. Also, sedimentation time was around four times smaller and sediment volume was 60% smaller than the values obtained in case of classical treatment. The necessary EB absorbed dose for the acrylamide - acrylic acid aqueous solution polymerization, established by optimization of chemical composition and irradiation

  13. Electron loss process and cross section of multiply charged ions by neutral atoms

    International Nuclear Information System (INIS)

    Karashima, S.; Watanabe, T.

    1985-01-01

    The significance of experimental and theoretical results on the electron loss and capture of ions in matter plays an important role in the charge equilibrium problems of fusion plasma physics and of accelerator physics. In the report, we calculate electron stripping cross section by using the binary encounter approximation (BEA). Our treatment of the electron loss process is based on BEA, in which the nucleus of B screened by the surrounding electrons collides with electrons in the ion A sup(q+). The basic approximation in EBA is that the ion interacts with only one electron or nucleus of the target atom at a time. In the calculation for Li sup(2+) + H, we have found that EBA will give approximately reliable results. (Mori, K.)

  14. Privacy Issues of Electronic Monitoring Of Employees: A Cross-Cultural Examination Of Gender Differences

    OpenAIRE

    Raymond E. Taylor

    2013-01-01

    This manuscript presents the results of a study which examined the privacy issues of electronic monitoring of employees from a cross-cultural perspective comparing participants from Taiwan with those from the United States. The results of the study suggest that gender differences exist between Taiwanese and American respondents’ attitudes concerning privacy issues of electronic monitoring of employees. The study suggests that monitoring with notice was an important parameter in determining ho...

  15. Total electron scattering cross sections for methanol and ethanol at intermediate energies

    International Nuclear Information System (INIS)

    Silva, D G M; Tejo, T; Lopes, M C A; Muse, J; Romero, D; Khakoo, M A

    2010-01-01

    Absolute total cross section (TCS) measurements of electron scattering from gaseous methanol and ethanol molecules are reported for impact energies from 60 to 500 eV, using the linear transmission method. The attenuation of intensity of a collimated electron beam through the target volume is used to determine the absolute TCS for a given impact energy, using the Beer-Lambert law to first approximation. Besides these experimental measurements, we have also determined TCS using the additivity rule.

  16. Comment on 'Integral cross sections for electron impact excitation of electronic states of N2'

    International Nuclear Information System (INIS)

    Cenian, A; Chernukho, A; Bogaerts, A; Gijbels, R

    2002-01-01

    Based on the existing experimental data and their statistical errors, it is not possible to make a sound recommendation of the cross-section set of Campbell et al (J. Phys. B: At. Mol. Opt. Phys. 34 (2001) 1185). We comment on this paper. (comment)

  17. The impact of texting on driver behaviour at rail level crossings.

    Science.gov (United States)

    Young, Kristie L; Lenné, Michael G; Salmon, Paul M; Stanton, Neville A

    2018-05-21

    A driver text messaging in the vicinity of a rail level crossing represents the merging of a high-risk, high-workload driving environment with a highly distracting secondary task. In this simulator study, we examined how texting impacts driver behaviour on approach to actively controlled urban rail level crossings. Twenty-eight participants drove a series of simulated urban routes containing rail level crossings, while sending text messages and while driving without performing a secondary task. At half of the crossings, drivers were required to respond to the crossing warnings as a train approached. Results revealed that texting on approach to rail level crossings had a detrimental impact on a range of driver behaviour measures. Specifically, texting more than doubled the amount of time spent with eyes off the forward roadway, resulting in drivers spending more than half of their approach time to rail level crossings looking away from the road. This lack of visual attention to the roadway was associated with a range of decrements in driving that may be indicative of a loss of situation awareness, including increased brake reaction time to the crossing warnings and a reduction in lateral position control. The findings have safety implications, not only for urban level crossings, but also for passive level crossings where no warnings are present to re-orient the distracted driver's attention toward an approaching train. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Measurements of electron-proton elastic cross sections for 0.4 2 2

    International Nuclear Information System (INIS)

    Christy, M.E.; Ahmidouch, Abdellah; Armstrong, Christopher; Arrington, John; Razmik Asaturyan; Steven Avery; Baker, O.; Douglas Beck; Henk Blok; Bochna, C.W.; Werner Boeglin; Peter Bosted; Maurice Bouwhuis; Herbert Breuer; Brown, D.S.; Antje Bruell; Roger Carlini; Nicholas Chant; Anthony Cochran; Leon Cole; Samuel Danagoulian; Donal Day; James Dunne; Dipangkar Dutta; Rolf Ent; Howard Fenker; Fox, B.; Liping Gan; Haiyan Gao; Kenneth Garrow; David Gaskell; Ashot Gasparian; Don Geesaman; Paul Gueye; Mark Harvey; Roy Holt; Xiaodong Jiang; Cynthia Keppel; Edward Kinney; Yongguang Liang; Wolfgang Lorenzon; Allison Lung; Pete Markowitz; Martin, J.W.; Kevin McIlhany; Daniella Mckee; David Meekins; Miller, J.W.; Richard Milner; Joseph Mitchell; Hamlet Mkrtchyan; Robert Mueller; Alan Nathan; Gabriel Niculescu; Maria-Ioana Niculescu; Thomas O'neill; Vassilios Papavassiliou; Stephen Pate; Buz Piercey; David Potterveld; Ronald Ransome; Joerg Reinhold; Rollinde, E.; Philip Roos; Adam Sarty; Reyad Sawafta; Elaine Schulte; Edwin Segbefia; Smith, C.; Stepan Stepanyan; Steffen Strauch; Vardan Tadevosyan; Liguang Tang; Raphael Tieulent; Alicia Uzzle; William Vulcan; Stephen Wood; Feng Xiong; Lulin Yuan; Markus Zeier; Benedikt Zihlmann; Vitaliy Ziskin

    2004-01-01

    We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The measurements were made at 28 unique kinematic settings covering a range in momentum transfer of 0.4 2 2 . These measurements represent a significant contribution to the world's cross section data set in the Q 2 range where a large discrepancy currently exists between the ratio of electric to magnetic proton form factors extracted from previous cross section measurements and that recently measured via polarization transfer in Hall A at Jefferson Lab

  19. The momentum transfer cross section and transport coefficients for low energy electrons in mercury

    International Nuclear Information System (INIS)

    McEachran, R P; Elford, M T

    2003-01-01

    The momentum transfer cross section for electrons incident on mercury atoms has been determined from the solution of Dirac-Fock scattering equations which included both static and dynamic multipole polarization potentials as well as full anti-symmetrization to incorporate exchange effects. This cross section is in excellent agreement between 0.2 and 3.0 eV with the cross section derived from the most recent experimental measurements. The discrepancy below 0.2 eV has been investigated using two-term transport theory

  20. Electronic Health Record-Related Safety Concerns: A Cross-Sectional Survey of Electronic Health Record Users

    Science.gov (United States)

    Pajunen, Tuuli; Saranto, Kaija; Lehtonen, Lasse

    2016-01-01

    Background The rapid expansion in the use of electronic health records (EHR) has increased the number of medical errors originating in health information systems (HIS). The sociotechnical approach helps in understanding risks in the development, implementation, and use of EHR and health information technology (HIT) while accounting for complex interactions of technology within the health care system. Objective This study addresses two important questions: (1) “which of the common EHR error types are associated with perceived high- and extreme-risk severity ratings among EHR users?”, and (2) “which variables are associated with high- and extreme-risk severity ratings?” Methods This study was a quantitative, non-experimental, descriptive study of EHR users. We conducted a cross-sectional web-based questionnaire study at the largest hospital district in Finland. Statistical tests included the reliability of the summative scales tested with Cronbach’s alpha. Logistic regression served to assess the association of the independent variables to each of the eight risk factors examined. Results A total of 2864 eligible respondents provided the final data. Almost half of the respondents reported a high level of risk related to the error type “extended EHR unavailability”. The lowest overall risk level was associated with “selecting incorrectly from a list of items”. In multivariate analyses, profession and clinical unit proved to be the strongest predictors for high perceived risk. Physicians perceived risk levels to be the highest (Prisk levels (PeLearning courses on EHR-use was associated with lower risk for some of the risk factors. Conclusions Based on a large number of Finnish EHR users in hospitals, this study indicates that HIT safety hazards should be taken very seriously, particularly in operating rooms, procedure units, emergency departments, and intensive care units/critical care units. Health care organizations should use proactive and

  1. Measurements of Electron Proton Elastic Cross Sections for 0.4

    International Nuclear Information System (INIS)

    Christy, M.E.; Abdellah Ahmidouch; Christopher Armstrong; John Arrington; Arshak Asaturyan; Steven Avery; Baker, O.; Douglas Beck; Henk Blok; Bochna, C.W.; Werner Boeglin; Peter Bosted; Maurice Bouwhuis; Herbert Breuer; Brown, D.S.; Antje Bruell; Roger Carlini; Nicholas Chant; Anthony Cochran; Leon Cole; Samuel Danagoulian; Donal Day; James Dunne; Dipangkar Dutta; Rolf Ent; Howard Fenker; Fox, B.; Liping Gan; Haiyan Gao; Kenneth Garrow; David Gaskell; Ashot Gasparian; Don Geesaman; Paul Gueye; Mark Harvey; Roy Holt; Xiaodong Jiang; Cynthia Keppel; Edward Kinney; Yongguang Liang; Wolfgang Lorenzon; Allison Lung; Pete Markowitz; Martin, J.W.; Kevin Mcilhany; David Mckee; David Meekins; Miller, M.A.; Richard Milner; Joseph Mitchell; Hamlet Mkrtchyan; Robert Mueller; Alan Nathan; Gabriel Niculescu; Maria-ioana Niculescu; Thomas O'neill; Vassilios Papavassiliou; Stephen Pate; Rodney Piercey; David Potterveld; Ronald Ransome; Joerg Reinhold; Rollinde, E.; Philip Roos; Adam Sarty; Reyad Sawafta; Elaine Schulte; Edwin Segbefia; Smith, C.; Samuel Stepanyan; Steffen Strauch; Vardan Tadevosyan; Liguang Tang; Raphael Tieulent; Alicia Uzzle; William Vulcan; Stephen Wood; Feng Xiong; Lulin Yuan; Markus Zeier; Benedikt Zihlmann; Vitaliy Ziskin

    2004-01-01

    We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The measurements were made at 28 distinct kinematic settings covering a range in momentum transfer of 0.4 < Q2 < 5.5 (GeV/c)2. These measurements represent a significant contribution to the world's cross section data set in the Q2 range, where a large discrepancy currently exists between the ratio of electric to magnetic proton form factors extracted from previous cross section measurements and that recently measured via polarization transfer in Hall A at Jefferson Lab. This data set shows good agreement with previous cross section measurements, indicating that if a heretofore unknown systematic error does exist in the cross section measurements, then it is intrinsic to all such measurements

  2. Fatal accidents at railway level crossings in Great Britain 1946-2009.

    Science.gov (United States)

    Evans, Andrew W

    2011-09-01

    This paper investigates fatal accidents and fatalities at level crossings in Great Britain over the 64-year period 1946-2009. The numbers of fatal accidents and fatalities per year fell by about 65% in the first half of that period, but since then have remained more or less constant at about 11 fatal accidents and 12 fatalities per year. At the same time other types of railway fatalities have fallen, so level crossings represent a growing proportion of the total. Nevertheless, Britain's level crossing safety performance remains good by international standards. The paper classifies level crossings into three types: railway-controlled, automatic, and passive. The safety performance of the three types of crossings has been very different. Railway-controlled crossings are the best-performing crossing type, with falling fatal accident rates. Automatic crossings have higher accident rates per crossing than railway controlled or passive crossings, and the accident rates have not decreased. Passive crossings are by far the most numerous, but many have low usage by road users. Their fatal accident rate has remained remarkably constant over the whole period at about 0.9 fatal accidents per 1000 crossings per year. A principal reason why fatal accidents and fatalities have not fallen in the second half of the period as they did in the first half is the increase in the number of automatic crossings, replacing the safer railway controlled crossings on some public roads. However, it does not follow that this replacement was a mistake, because automatic crossings have advantages over controlled crossings in reducing delays to road users and in not needing staff. Based on the trends for each type of crossing and for pedestrian and non-pedestrian accidents separately, in 2009 a mean of about 5% of fatal accidents were at railway controlled crossings, 52% were at automatic crossings, and 43% were at passive crossings. Fatalities had similar proportions. About 60% of fatalities were

  3. Privacy Issues of Electronic Monitoring Of Employees: A Cross-Cultural Examination Of Gender Differences

    Directory of Open Access Journals (Sweden)

    Raymond E. Taylor

    2013-07-01

    Full Text Available This manuscript presents the results of a study which examined the privacy issues of electronic monitoring of employees from a cross-cultural perspective comparing participants from Taiwan with those from the United States. The results of the study suggest that gender differences exist between Taiwanese and American respondents’ attitudes concerning privacy issues of electronic monitoring of employees. The study suggests that monitoring with notice was an important parameter in determining how privacy issues of electronic monitoring of employees were viewed by the participants.

  4. Relating measurement invariance, cross-level invariance, and multilevel reliability

    NARCIS (Netherlands)

    Jak, S.; Jorgensen, T.D.

    2017-01-01

    Data often have a nested, multilevel structure, for example when data are collected from children in classrooms. This kind of data complicate the evaluation of reliability and measurement invariance, because several properties can be evaluated at both the individual level and the cluster level, as

  5. Differential cross sections for the one electron two center symmetric systems

    International Nuclear Information System (INIS)

    Maidagan, J.M.; Piacentini, R.D.; Rivarola, R.D.; Universidad Autonoma de Madrid

    1982-01-01

    We use the two-state atomic expansion with variable nuclear charge to study charge-exchange differential cross sections for symmetrical one-electron systems at intermediate energy. The nonclassical small angle diffraction scattering is discussed. Our results are compared with data for H + -H collisions. (orig.)

  6. Differential cross sections for the one electron two center symmetric systems

    Energy Technology Data Exchange (ETDEWEB)

    Maidagan, J.M.; Piacentini, R.D. (Universidad Nacional de Rosario (Argentina). Dept. de Fisica); Rivarola, R.D. (Bordeaux-1 Univ., 33 - Talence (France). Lab. d' Astrophysique; Universidad Autonoma de Madrid (Spain). Dept. de Quimica Fisica y Quimica Cuantica)

    1982-03-01

    We use the two-state atomic expansion with variable nuclear charge to study charge-exchange differential cross sections for symmetrical one-electron systems at intermediate energy. The nonclassical small angle diffraction scattering is discussed. Our results are compared with data for H/sup +/-H collisions.

  7. Experimental and theoretical electron-scattering cross-section data for dichloromethane

    Science.gov (United States)

    Krupa, K.; Lange, E.; Blanco, F.; Barbosa, A. S.; Pastega, D. F.; Sanchez, S. d'A.; Bettega, M. H. F.; García, G.; Limão-Vieira, P.; Ferreira da Silva, F.

    2018-04-01

    We report on a combination of experimental and theoretical investigations into the elastic differential cross sections (DCSs) and integral cross sections for electron interactions with dichloromethane, C H2C l2 , in the incident electron energy over the 7.0-30 eV range. Elastic electron-scattering cross-section calculations have been performed within the framework of the Schwinger multichannel method implemented with pseudopotentials (SMCPP), and the independent-atom model with screening-corrected additivity rule including interference-effects correction (IAM-SCAR+I). The present elastic DCSs have been found to agree reasonably well with the results of IAM-SCAR+I calculations above 20 eV and also with the SMC calculations below 30 eV. Although some discrepancies were found for 7 eV, the agreement between the two theoretical methodologies is remarkable as the electron-impact energy increases. Calculated elastic DCSs are also reported up to 10000 eV for scattering angles from 0° to 180° together with total cross section within the IAM-SCAR+I framework.

  8. Cross-national social work case analysis: learning from international experience within an electronic environment

    NARCIS (Netherlands)

    R. Kloppenburg; V. Gevorgianiene; V. Jakutiene; Peter Hendriks

    2008-01-01

    This article presents the results of a pilot of a cross-national learning process within the context of social work education. The pilot was carried out in the electronic environment by students from four European universities (Hogeschool Utrecht, Sheffield, Tartu and Vilnius). The analysis of the

  9. Electron cyclotron instabilities of finite pressure inhomogeneous plasma in crossed fields

    International Nuclear Information System (INIS)

    Kirochkin, Yu.A.; Pokroev, A.G.; Stepanov, K.N.

    1979-01-01

    The stability of inhomogeneous plasma sheet with β<=1 in crossed electric and magnetic fields is investigated. The differential equation describing potential oscillations is obtained. Using the local approximation the sheet is shown to be unstable against the excitation of short wavelength electron cyclotron oscillations. The validity criterion of this method for a given type of waves is derived

  10. Cross-Border Electronic Commerce : Distance Effects and Express Delivery in European Union Markets

    NARCIS (Netherlands)

    T.Y. Kim (Thai Young); R. Dekker (Rommert); C. Heij (Christiaan)

    2017-01-01

    textabstractThis empirical study examines distance effects on cross-border electronic commerce and in particular the importance of express delivery in reducing the time dimension of distance. E-commerce provides suppliers with a range of opportunities to reduce distance as perceived by online

  11. Measurement of integral cross-sections of incoherent interactions of photons with K-shell electrons

    Energy Technology Data Exchange (ETDEWEB)

    Verma, S L; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Dept. of Physics. Nuclear Science Labs.

    1981-06-01

    Integral cross-sections of incoherent interactions of 145, 279, 662 and 1250 keV gamma-rays with K-shell electrons of thirty-one different elements with 26 <= Z <= 92 have been measured. The results are interpreted in terms of the photoelectric and Compton interactions and are found to agree with theory.

  12. Absolute experimental cross sections for the electron impact ionization of rubidium. Technical summary report

    International Nuclear Information System (INIS)

    Hughes, D.W.; Feeney, R.K.

    1980-01-01

    The absolute cross sections for the double, triple, and quadruple ionization of Rb + ions by electron impact have been measured from below their respective thresholds to approximately 3000 eV. This determination has been accomplished using a crossed beam facility in which monoenergetic beams of ions and electrons are caused to intersect at right angles in a well-defined collision volume. Multiply charged, product ions born as a result of the electron impact are deflected into their respective detectors by cascaded electrostatic analyzers. The multiply charged beam current component is measured by means of a vibrating reed electrometer operating in the rate-of-charge mode. The required singly charged rubidium ions are produced in a thermionic ion source and pass through a series of focusing, collimating and deflecting structures before entering the interaction region. A thermionically generated, rectangular electron beam intercepts the target ions in a spatially designated collision volume. Just prior to entering this interaction region the two beams can be made to pass through a movable slit scanner which determines their spatial profiles. The various charged particle currents, energies and beam current density distributions represent the experimental data from which the desired absolute cross sections have been determined. The results obtained with this technique are compared with available theoretical predictions of the appropriate cross sections

  13. Absolute differential cross sections for elastic scattering of electrons by helium, neon, argon and molecular nitrogen

    International Nuclear Information System (INIS)

    Jansen, R.H.J.; De Heer, F.J.; Luyken, H.J.; Van Wingerden, B.

    1976-01-01

    An electron spectrometer has been constructed for the study of elastic and inelastic electron scattering processes. Up to now the apparatus has been used to measure differential cross sections of electrons elastically scattered by He, Ne, Ar and N 2 . Direct absolute cross section measurements were performed on N 2 at 500 eV impact energy and at scattering angles between 5 0 and 9 0 . Relative cross section measurements were done on He, Ne, Ar and N 2 at impact energies between 100 and 3000 eV and scattering angles between 5 0 and 55 0 . The relative cross sections were put on an absolute scale by means of the apparatus calibration factor derived from the absolute measurements on N 2 . The experimental apparatus and procedure are described in detail. The results are discussed and compared with those of other experimental and theoretical groups. Analysis of the exponential behaviour of the differential cross section as a function of momentum transfer yielded apparent polarizabilities of the target. (author)

  14. The LXCat project: Electron scattering cross sections and swarm parameters for low temperature plasma modeling

    International Nuclear Information System (INIS)

    Pancheshnyi, S.; Biagi, S.; Bordage, M.C.; Hagelaar, G.J.M.; Morgan, W.L.; Phelps, A.V.; Pitchford, L.C.

    2012-01-01

    Graphical abstract: LXCat is an open-access website containing data needed for low temperature plasma modeling as well as on-line tools useful for their manipulation. Highlights: ► LXCat: an open-access website with data for low temperature plasma modeling. ► Contains compilations of electron scattering cross sections and transport data. ► Data from different contributors for many neutral, ground-state species. ► On-line tools for browsing, plotting, up/downloading data. ► On-line Boltzmann solver for calculating electron swarm parameters. - Abstract: LXCat is a dynamic, open-access, website for collecting, displaying, and downloading ELECtron SCATtering cross sections and swarm parameters (mobility, diffusion coefficient, reaction rates, etc.) required for modeling low temperature, non-equilibrium plasmas. Contributors set up individual databases, and the available databases, indicated by the contributor’s chosen title, include mainly complete sets of electron-neutral scattering cross sections, although the option for introducing partial sets of cross sections exists. A database for measured swarm parameters is also part of LXCat, and this is a growing activity. On-line tools include options for browsing, plotting, and downloading cross section data. The electron energy distribution functions (edfs) in low temperature plasmas are in general non-Maxwellian, and LXCat provides an option for execution of an on-line Boltzmann equation solver to calculate the edf in homogeneous electric fields. Thus, the user can obtain electron transport and rate coefficients (averages over the edfs) in pure gases or gas mixtures over a range of values of the reduced electric fields strength, E/N, the ratio of the electric field strength to the neutral density, using cross sections from the available databases. New contributors are welcome and anyone wishing to create a database and upload data can request a username and password. LXCat is part of a larger, community

  15. Theoretical calculation of fully differential cross sections for electron-impact ionization of hydrogen molecules

    International Nuclear Information System (INIS)

    Gao Junfang; Madison, D H; Peacher, J L

    2006-01-01

    We have recently proposed the orientation averaged molecular orbital (OAMO) approximation for calculating fully differential cross sections (FDCS) for electron-impact ionization of molecules averaged over all molecular orientations. Orientation averaged FDCS were calculated for electron-impact ionization of nitrogen molecules using the distorted wave impulse approximation (DWIA) and the molecular three-body distorted wave (M3DW) approximation. In this paper, we use the same methods to examine the FDCS for ionization of hydrogen molecules. It is found that the DWIA yields reasonable results for high-energy incident electrons. While the DWIA breaks down for low-energy electrons, the M3DW gives reasonable results down to incident-electron energies around 35 eV

  16. INDIVIDUAL DAN ORGANIZATIONAL UNLEARNING: PROPOSISI HUBUNGAN MODERASI CROSS-LEVEL

    Directory of Open Access Journals (Sweden)

    Henri Dwi Wahyudi

    2016-08-01

    Full Text Available Unlearning stripped result old learning to give space for new information and new attitude. Unlearning is undoubtedly for individu or organization to receive new knowledge (herdberg,1981, increase innovation performance (pighin &Marzona,2011 and increase the company abbility to facing  crisis (Starbuck, 1995, this article give six preposision that connect the literature from micro level and macro level use the mediation variable, multi level moderation to explain the fenomena in organizational behavior that don’t have enough support in empirical, individual and organizational unlearning.

  17. Electron-detachment cross sections of halogen negative-ion projectiles for inertial confinement fusion

    Science.gov (United States)

    Sant'Anna, M. M.; Zappa, F.; Santos, A. C. F.; de Barros, A. L. F.; Wolff, W.; Coelho, L. F. S.; de Castro Faria, N. V.

    2004-07-01

    Negative-ion beams have recently been suggested as sources of high-energy heavy atoms to be used as drivers for inertial confinement fusion (ICF). Owing to their electron affinities limited to a few eV, anions can be efficiently photo-detached in the vicinity of the fusion chamber, with the resulting high-velocity neutral projectiles following ballistic trajectories towards the hydrogen pellet target. Electron-detachment cross sections are needed as parameters to estimate the beam attenuation in the path from the ion source to the hydrogen pellet. Halogen anions are possible projectile choices. In this paper we present experimental data for total electron-detachment cross sections for F-, Cl-, Br- and I- ions incident on N2, in the 0.94-74 keV u-1 energy range. Our measurements can benchmark theory on anion electron detachment at intermediate to high velocities. Comparison between different projectiles shows very similar collision velocity dependencies. A simple geometrical scaling is presented, providing an estimate for electron-detachment cross sections at the MeV u-1 energy range. The presented scaling indicates that the vacuum requirements due to the use of halogen anions for ICF are less critical than previously suggested.

  18. Electron-detachment cross sections of halogen negative-ion projectiles for inertial confinement fusion

    International Nuclear Information System (INIS)

    Sant'Anna, M M; Zappa, F; Santos, A C F; Barros, A L F de; Wolff, W; Coelho, L F S; Faria, N V de Castro

    2004-01-01

    Negative-ion beams have recently been suggested as sources of high-energy heavy atoms to be used as drivers for inertial confinement fusion (ICF). Owing to their electron affinities limited to a few eV, anions can be efficiently photo-detached in the vicinity of the fusion chamber, with the resulting high-velocity neutral projectiles following ballistic trajectories towards the hydrogen pellet target. Electron-detachment cross sections are needed as parameters to estimate the beam attenuation in the path from the ion source to the hydrogen pellet. Halogen anions are possible projectile choices. In this paper we present experimental data for total electron-detachment cross sections for F - , Cl - , Br - and I - ions incident on N 2 , in the 0.94-74 keV u -1 energy range. Our measurements can benchmark theory on anion electron detachment at intermediate to high velocities. Comparison between different projectiles shows very similar collision velocity dependencies. A simple geometrical scaling is presented, providing an estimate for electron-detachment cross sections at the MeV u -1 energy range. The presented scaling indicates that the vacuum requirements due to the use of halogen anions for ICF are less critical than previously suggested

  19. Collision cross sections for few electron systems. Final report, August 1, 2992--July 31, 1995

    International Nuclear Information System (INIS)

    Reading, J.F.; Ford, A.L.

    1995-01-01

    The purpose of this project was to produce accurate cross sections for collisionally induced reactions from the ground stated and excited states of species of ions and at present in a hot fusion plasma. The collisional constituents may be divided into two categories for the purpose of calculations: Those in which a bare projectile excites a one electron or two electron ion or atom from its ground state, or excited states to higher excited states or ionized states. Those in which the projectile has one or more electrons attached to it and excites a one electron or two electron ion or atom from its ground state, or excited states to higher excited states or ionized states. During the collision the projectile itself may change its state being simultaneously excited or ionized. Cross sections are needed typically over the whole energy range from low velocities where molecular, orbitals begin to form to high velocities where first Born or more sophisticated asymptotic theories can be used. These high energy cross sections are very useful for experimentalists to check the absolute normalization of their cross sections. The theoretical tools used were therefore both analytical and numerical in character. Numerical calculations were restricted to expansions of the wavefunctions in a set of finite hilbert basis states (FHBS). The many body aspects of the problem, i.e. the important presence of the interelectron force, or correlation mandate a careful systematic approach. But this section was tempered in our strategy by the fact that many of the cross sections needed, especially from excited states, have never been calculated or measured at all. Thus any information we can provide is useful even if later work may modify our results

  20. Rosetta Mission: Electron Scattering Cross Sections—Data Needs and Coverage in BEAMDB Database

    Directory of Open Access Journals (Sweden)

    Bratislav P. Marinković

    2017-11-01

    Full Text Available The emission of [O I] lines in the coma of Comet 67P/Churyumov-Gerasimenko during the Rosetta mission have been explained by electron impact dissociation of water rather than the process of photodissociation. This is the direct evidence for the role of electron induced processing has been seen on such a body. Analysis of other emission features is handicapped by a lack of detailed knowledge of electron impact cross sections which highlights the need for a broad range of electron scattering data from the molecular systems detected on the comet. In this paper, we present an overview of the needs for electron scattering data relevant for the understanding of observations in coma, the tenuous atmosphere and on the surface of 67P/Churyumov-Gerasimenko during the Rosetta mission. The relevant observations for elucidating the role of electrons come from optical spectra, particle analysis using the ion and electron sensors and mass spectrometry measurements. To model these processes electron impact data should be collated and reviewed in an electron scattering database and an example is given in the BEAMD, which is a part of a larger consortium of Virtual Atomic and Molecular Data Centre—VAMDC.

  1. Resonance effects in elastic cross sections for electron scattering on pyrimidine: Experiment and theory.

    Science.gov (United States)

    Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D

    2016-01-14

    We measured differential cross sections for elastic (rotationally integrated) electron scattering on pyrimidine, both as a function of angle up to 180(∘) at electron energies of 1, 5, 10, and 20 eV and as a function of electron energy in the range 0.1-14 eV. The experimental results are compared to the results of the fixed-nuclei Schwinger variational and R-matrix theoretical methods, which reproduce satisfactorily the magnitudes and shapes of the experimental cross sections. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. Resonant structures are observed at 0.2, 0.7, and 4.35 eV and calculations for different symmetries confirm their assignment as the X̃(2)A2, Ã(2)B1, and B̃(2)B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B̃(2)B1 shape resonance appears as a peak, a dip, or a step function in the cross sections recorded as a function of energy at different scattering angles and this effect is satisfactorily reproduced by theory. The dip and peak contributions at different scattering angles partially compensate, making the resonance nearly invisible in the integral cross section. Vibrationally integrated cross sections were also measured at 1, 5, 10 and 20 eV and the question of whether the fixed-nuclei cross sections should be compared to vibrationally elastic or vibrationally integrated cross section is discussed.

  2. Experimental Results on the Level Crossing Intervals of the Phase of Sine Wave Plus Noise

    Science.gov (United States)

    Youssef, Neji; Munakata, Tsutomu; Mimaki, Tadashi

    1993-03-01

    Experimental study was made on the level crossing intervals of a phase process of a sine wave plus narrow-band Gaussian noise. Since successive level crossings of phase do not necessarily occur alternately in the upward and downward direction due to the phase jump beyond 2π, the usual definitions of the probability densities of the level crossing intervals for continuous random processes are not applicable in the case of the phase process. Therefore, the probability densities of level crossing intervals of phase process are newly defined. Measurements of these densities were performed for noise having lowpass spectra of Gaussian and 7th order Butterworth types. Results are given for various values of the signal-to-noise power ratio and of the crossing level, and compared with corresponding approximation developed under the assumption of quasi-independence. The validity of the assumption depends on the spectrum shape of the noise.

  3. Thick-target method in the measurement of inner-shell ionization cross-sections by low-energy electron impact

    International Nuclear Information System (INIS)

    An, Z.; Wu, Y.; Liu, M.T.; Duan, Y.M.; Tang, C.H.

    2006-01-01

    In this paper, we have studied the thick-target method for the measurements of atomic inner-shell ionization cross-section or X-ray production cross-section by keV electron impact. We find that in the processes of electron impact on the thick targets, the ratios of the characteristic X-ray yields of photoelectric ionization by bremsstrahlung to the total characteristic X-ray yields are Z-dependent and shell-dependent, and the ratios also show the weak energy-dependence. In addition, in the lower incident energy region (i.e. U < 5-6), the contribution from the rediffusion effect and the secondary electrons can be negligible. In general, the thick-target method can be appropriately applied to the measurements of atomic inner-shell ionization cross-sections or X-ray production cross-sections by electron impact for low and medium Z elements in the lower incident electron energy (i.e. U < 5-6). The experimental accuracies by the thick-target method can reach to the level equivalent or superior to the accuracies of experimental data based on the thin-target method. This thick-target method has been applied to the measurement of K-shell ionization cross-sections of Ni element by electron impact in this paper

  4. Differential cross sections for elastic scattering of electrons by atoms and solids

    International Nuclear Information System (INIS)

    Jablonski, A.; Salvat, F.; Powell, C.J.

    2004-01-01

    Differential cross sections (DCSs) for elastic scattering of electrons by neutral atoms are extensively used in studies of electron transport in solids and liquids. A new NIST database has recently been released with DCSs calculated from a relativistic Dirac partial-wave analysis in which the potentials were obtained from Dirac-Hartree-Fock electron densities computed self-consistently for free atoms. We have compared calculated DCSs with measured DCSs for argon for electron energies between 50 eV and 3 keV, and found good agreement for electron energies above about 1 keV but with increasing deviations as the energy is reduced. These deviations are due to the neglect of absorption and polarizability effects in the calculations. Nevertheless, DCSs for neutral atoms have been successfully used in simulations of elastic backscattering of electrons by solid surfaces with energies down to 300 eV as well as for many other applications. It is suggested that this success might be due at least partially to the smaller absorption correction for the DCSs in solids on account of the smaller total inelastic scattering cross sections than for the corresponding free atoms

  5. Level crossings in complex two-dimensional potentials

    Indian Academy of Sciences (India)

    Two-dimensional P T -symmetric quantum-mechanical systems with the complex cubic potential 12 = 2 + 2 + 2 and the complex Hénon–Heiles potential HH = 2 + 2 + (2 − 3/3) are investigated. Using numerical and perturbative methods, energy spectra are obtained to high levels. Although both ...

  6. Levels, Linkages, and Networks in Cross-Cultural Innovation.

    Science.gov (United States)

    Kennedy, Judith; Kennedy, Chris

    1998-01-01

    Individuals belong to different cultural networks, and these networks and connections between them play an important role in success or failure of educational innovation and should be included in any model of the management or evaluation of innovation. Looks at functions of the different networks to which individuals belong at three levels,…

  7. Power Analysis for Cross Level Mediation in CRTs

    Science.gov (United States)

    Kelcey, Ben

    2014-01-01

    A common design in education research for interventions operating at a group or cluster level is a cluster randomized trial (CRT) (Bloom, 2005). In CRTs, intact clusters (e.g., schools) are assigned to treatment conditions rather than individuals (e.g., students) and are frequently an effective way to study interventions because they permit…

  8. Correction of the near threshold behavior of electron collisional excitation cross-sections in the plane-wave Born approximation

    Science.gov (United States)

    Kilcrease, D. P.; Brookes, S.

    2013-12-01

    The modeling of NLTE plasmas requires the solution of population rate equations to determine the populations of the various atomic levels relevant to a particular problem. The equations require many cross sections for excitation, de-excitation, ionization and recombination. A simple and computational fast way to calculate electron collisional excitation cross-sections for ions is by using the plane-wave Born approximation. This is essentially a high-energy approximation and the cross section suffers from the unphysical problem of going to zero near threshold. Various remedies for this problem have been employed with varying degrees of success. We present a correction procedure for the Born cross-sections that employs the Elwert-Sommerfeld factor to correct for the use of plane waves instead of Coulomb waves in an attempt to produce a cross-section similar to that from using the more time consuming Coulomb Born approximation. We compare this new approximation with other, often employed correction procedures. We also look at some further modifications to our Born Elwert procedure and its combination with Y.K. Kim's correction of the Coulomb Born approximation for singly charged ions that more accurately approximate convergent close coupling calculations.

  9. Application of polymers cross-linked by electron beam irradiation to electric wire industry

    International Nuclear Information System (INIS)

    Oda, Eisuke

    1976-01-01

    Applications of the polymers cross-linked by electron beam irradiation to electric wire industry as an example of dully developed utilization are reviewed. The report is divided into five parts, namely 1) radiation sources and irradiation processes, 2) development of crosslinking materials, 3) accumulation of electric charge and accumulation of heat, 4) examples of application, and 5) future prospect. Such a phenomenon as discharge destruction pattern (Lichtenberg figure) must be solved, when cable insulation materials are cross-linked by electron beam irradiation. The measures for preventing the discharge destruction are required, especially when the layers of polyethylene insulation for high voltage cables are irradiated. The accumulation of heat causes the troubles in foaming, degeneration and wire running of high potential cables, when the layers of insulation are thick. Effective promoters for cross-linking must be studied to reduce the radiation dose. The irradiators capable of irradiating wires uniformly are desirable. Electron beam accelerators will be used, as far as the radiation dose of 10 or more Mrad is required for cross-linking irradiation. If the dose of one tenth or less of the above value is required, gamma-ray sources (RI) are rather easily applicable than focused strong beam. The utilization of spent nuclear fuel is desirable. (Iwakiri, K.)

  10. Cross-cultural differences in levels of knowledge about epilepsy.

    Science.gov (United States)

    Doughty, Julie; Baker, Gus A; Jacoby, Ann; Lavaud, Virginie

    2003-01-01

    To study how much people with epilepsy in Europe know and understand about their condition and how this might affect their lives. Clinical, demographic, psychosocial details and information assessing knowledge were collected by using self-completion questionnaires mailed to members of epilepsy support groups. Data were collected from 6,156 people with epilepsy from ten European countries. There were significant between-country differences in all variables considered. Overall levels of knowledge were acceptable when measured by the epilepsy knowledge questionnaire (EKQ, medical items). However, there were some gaps in knowledge, particularly in issues relating to medication and cause of epilepsy. This is the largest study of its kind to date. Results clearly highlighted that levels of knowledge differed significantly between countries. Overall, people with epilepsy are reasonably well informed about epilepsy, although some gaps in knowledge were evident.

  11. Total photoionization cross-sections of excited electronic states by the algebraic diagrammatic construction-Stieltjes-Lanczos method.

    Science.gov (United States)

    Ruberti, M; Yun, R; Gokhberg, K; Kopelke, S; Cederbaum, L S; Tarantelli, F; Averbukh, V

    2014-05-14

    Here, we extend the L2 ab initio method for molecular photoionization cross-sections introduced in Gokhberg et al. [J. Chem. Phys. 130, 064104 (2009)] and benchmarked in Ruberti et al. [J. Chem. Phys. 139, 144107 (2013)] to the calculation of total photoionization cross-sections of molecules in electronically excited states. The method is based on the ab initio description of molecular electronic states within the many-electron Green's function approach, known as algebraic diagrammatic construction (ADC), and on the application of Stieltjes-Chebyshev moment theory to Lanczos pseudospectra of the ADC electronic Hamiltonian. The intermediate state representation of the dipole operator in the ADC basis is used to compute the transition moments between the excited states of the molecule. We compare the results obtained using different levels of the many-body theory, i.e., ADC(1), ADC(2), and ADC(2)x for the first two excited states of CO, N2, and H2O both at the ground state and the excited state equilibrium or saddle point geometries. We find that the single excitation ADC(1) method is not adequate even at the qualitative level and that the inclusion of double electronic excitations for description of excited state photoionization is essential. Moreover, we show that the use of the extended ADC(2)x method leads to a substantial systematic difference from the strictly second-order ADC(2). Our calculations demonstrate that a theoretical modelling of photoionization of excited states requires an intrinsically double excitation theory with respect to the ground state and cannot be achieved by the standard single excitation methods with the ground state as a reference.

  12. New techniques for multi-level cross section calculation and fitting

    International Nuclear Information System (INIS)

    Froehner, F.H.

    1981-01-01

    A number of recent developments in multi-level cross section work are described. A new iteration scheme for the conversion of Reich-Moore resonance parameters to Kapur-Peierls parameters allows application of Turing's method for Gaussian broadening of meromorphic functions directly to multi-level cross section expressions, without recourse to the Voigt profiles psi and chi. This makes calculation of Doppler-broadened Reich-Moore and MLBW cross sections practically as fast as SLBW and Adler-Adler cross section calculations involving the Voigt profiles. A convenient distant-level treatment utilizing average resonance parameters is presented. Apart from effectively dealing with edge effects in resonance fitting work it also leads to a simple prescription for the determination of bound levels which reproduce the thermal cross sections correctly. A brief discussion of improved resonance shape fitting techniques is included, with emphasis on the importance of correlated errors and proper use of prior information by application of Bayes' theorem

  13. Measurement of the High-Mass Drell-Yan Cross Section and Limits on Quark-Electron Compositeness Scales

    International Nuclear Information System (INIS)

    Grinstein, S.; Mostafa, M.; Piegaia, R.; Alves, G.A.; Carvalho, W.; Maciel, A.K.; Motta, H. da; Oliveira, E.; Santoro, A.; Lima, J.G.; Oguri, V.; Gomez, B.; Hoeneisen, B.; Mooney, P.; Negret, J.P.; Ducros, Y.; Beri, S.B.; Bhatnagar, V.; Kohli, J.M.; Singh, J.B.; Shivpuri, R.K.; Acharya, B.S.; Banerjee, S.; Dugad, S.R.; Gupta, A.; Krishnaswamy, M.R.; Mondal, N.K.; Narasimham, V.S.; Parua, N.; Shankar, H.C.; Park, Y.M.; Choi, S.; Kim, S.K.; Castilla-Valdez, H.; Gonzalez Solis, J.L.; Hernandez-Montoya, R.; Magana-Mendoza, L.; Sanchez-Hernandez, A.; Pawlik, B.; Gavrilov, V.; Gershtein, Y.; Kuleshov, S.; Belyaev, A.; Dudko, L.V.; Ermolov, P.; Karmanov, D.; Leflat, A.; Manankov, V.; Merkin, M.; Shabalina, E.; Abramov, V.; Babintsev, V.V.; Bezzubov, V.A.; Bojko, N.I.; Burtovoi, V.S.; Chekulaev, S.V.; Denisov, S.P.; Dyshkant, A.; Eroshin, O.V.; Evdokimov, V.N.; Galyaev, A.N.; Goncharov, P.I.; Gurzhiev, S.N.; Kostritskiy, A.V.; Kozelov, A.V.; Kozlovsky, E.A.; Mayorov, A.A.; Babukhadia, L.; Davis, K.; Fein, D.; Forden, G.E.; Guida, J.A.; Johns, K.; Nang, F.; Narayanan, A.; Rutherfoord, J.; Shupe, M.; Aihara, H.; Barberis, E.; Clark, A.R.

    1999-01-01

    We present a measurement of the Drell-Yan cross section at high dielectron invariant mass using 120 pb -1 of data collected in p bar p collisions at √ (s) =1.8 TeV by the D0 Collaboration during 1992 - 1996. No deviation from standard model expectations is observed. We use the data to set limits on the quark-electron compositeness scale. The 95% confidence level lower limits on the compositeness scale vary between 3.3 and 6.1thinspthinspTeV depending on the assumed form of the effective contact interaction. copyright 1999 The American Physical Society

  14. The feasibility of using neural networks to obtain cross sections from electron swarm data

    International Nuclear Information System (INIS)

    Morgan, W.L.

    1991-01-01

    This paper reports that although still more a curiosity than an accepted technique in computational modeling, the very new field of neural computing is beginning to find applications in physics. Presented in some background on neural computing and a discussion on the use of neural networks to obtain electron-impact cross sections from measured drift velocities, characteristic energies, and other swarm data. This is what is known as an inverse problem, a class of problems for which neural networks may be frequently superior to other numerical algorithms. Momentum transfer cross sections obtained for a model problem and for xenon using a neural network are presented

  15. Differential cross sections for the elastic scattering of intermediate energy electrons from sodium

    International Nuclear Information System (INIS)

    Teubner, P.J.O.; Buckner, S.J.; Noble, C.J.

    1977-11-01

    Differential cross sections for the elastic scattering of electrons from sodium have been measured with high angular resolution for incident energies of 54.4, 75, 100 and 150 eV and over an angular range of 12 0 to 140 0 . The experimental data are compared with calculations based on the First Born approximation, the Glauber approximation and a close coupling impact parameter calculation. Calculations have been carried out for an optical model using the prescription of Vanderpoorten for localizing the absorptive part of the potential. Of the theoretical calculations the optical model is found to best reproduce the general features of the cross section at all energies. (Author)

  16. Empirical Fit to Precision Inclusive Electron-Proton Cross Sections in the Resonance Region

    International Nuclear Information System (INIS)

    M.E. Christy; Peter Bosted

    2007-01-01

    An empirical fit is described to measurements of inclusive inelastic electron-proton cross sections in the kinematic range of four-momentum transfer 0 (le) Q 2 2 and final state invariant mass 1.1 2 ∼ 7.5 GeV 2 , and photoproduction data at Q 2 = 0. Compared to previous fits, the present fit covers a wider kinematic range, fits both transverse and longitudinal cross sections, and features smooth transitions to the photoproduction data at Q 2 =0 and DIS data at high Q 2 and W

  17. MUTIL, Asymmetry Factor of Mott Cross-Sections for Electron, Positron Scattering

    International Nuclear Information System (INIS)

    Idoeta, R.; Legarda, F.

    2002-01-01

    1 - Description of program or function: The asymmetry factor S of Mott's differential cross section for the scattering of electrons and positrons by point nuclei without screening is calculated for any energy, atomic number and angle of scattering. 2 - Method of solution: We have summed the conditionally convergent series, F and G, appearing in the asymmetry factor using two consecutive transformations: The one of Yennie, Ravenhall and Wilson and that of Euler till we have seven times six significant figures repeated in the factor S. 3 - Restrictions on the complexity of the problem: Those appearing in the use of Mott's cross section for unscreened point nuclei

  18. Absolute total and one and two electron transfer cross sections for Ar8+ on Ar as a function of energy

    International Nuclear Information System (INIS)

    Vancura, J.; Kostroun, V.O.

    1992-01-01

    The absolute total and one and two electron transfer cross sections for Ar 8+ on Ar were measured as a function of projectile laboratory energy from 0.090 to 0.550 keV/amu. The effective one electron transfer cross section dominates above 0.32 keV/amu, while below this energy, the effective two electron transfer starts to become appreciable. The total cross section varies by a factor over the energy range explored. The overall error in the cross section measurement is estimated to be ± 15%

  19. Energy level alignment and electron transport through metal/organic contacts. From interfaces to molecular electronics

    Energy Technology Data Exchange (ETDEWEB)

    Abad, Enrique

    2013-07-01

    A new calculational approach to describing metal/organic interfaces. A valuable step towards a better understanding of molecular electronics. Nominated as an outstanding contribution by the Autonomous University of Madrid. In recent years, ever more electronic devices have started to exploit the advantages of organic semiconductors. The work reported in this thesis focuses on analyzing theoretically the energy level alignment of different metal/organic interfaces, necessary to tailor devices with good performance. Traditional methods based on density functional theory (DFT), are not appropriate for analyzing them because they underestimate the organic energy gap and fail to correctly describe the van der Waals forces. Since the size of these systems prohibits the use of more accurate methods, corrections to those DFT drawbacks are desirable. In this work a combination of a standard DFT calculation with the inclusion of the charging energy (U) of the molecule, calculated from first principles, is presented. Regarding the dispersion forces, incorrect long range interaction is substituted by a van der Waals potential. With these corrections, the C60, benzene, pentacene, TTF and TCNQ/Au(111) interfaces are analyzed, both for single molecules and for a monolayer. The results validate the induced density of interface states model.

  20. Tree-indexed processes: a high level crossing analysis

    Directory of Open Access Journals (Sweden)

    Mark Kelbert

    2003-01-01

    Full Text Available Consider a branching diffusion process on R1 starting at the origin. Take a high level u>0 and count the number R(u,n of branches reaching u by generation n. Let Fk,n(u be the probability P(R(u,n

  1. Cross-Level Effects Between Neurophysiology and Communication During Team Training.

    Science.gov (United States)

    Gorman, Jamie C; Martin, Melanie J; Dunbar, Terri A; Stevens, Ronald H; Galloway, Trysha L; Amazeen, Polemnia G; Likens, Aaron D

    2016-02-01

    We investigated cross-level effects, which are concurrent changes across neural and cognitive-behavioral levels of analysis as teams interact, between neurophysiology and team communication variables under variations in team training. When people work together as a team, they develop neural, cognitive, and behavioral patterns that they would not develop individually. It is currently unknown whether these patterns are associated with each other in the form of cross-level effects. Team-level neurophysiology and latent semantic analysis communication data were collected from submarine teams in a training simulation. We analyzed whether (a) both neural and communication variables change together in response to changes in training segments (briefing, scenario, or debriefing), (b) neural and communication variables mutually discriminate teams of different experience levels, and (c) peak cross-correlations between neural and communication variables identify how the levels are linked. Changes in training segment led to changes in both neural and communication variables, neural and communication variables mutually discriminated between teams of different experience levels, and peak cross-correlations indicated that changes in communication precede changes in neural patterns in more experienced teams. Cross-level effects suggest that teamwork is not reducible to a fundamental level of analysis and that training effects are spread out across neural and cognitive-behavioral levels of analysis. Cross-level effects are important to consider for theories of team performance and practical aspects of team training. Cross-level effects suggest that measurements could be taken at one level (e.g., neural) to assess team experience (or skill) on another level (e.g., cognitive-behavioral). © 2015, Human Factors and Ergonomics Society.

  2. Determining of electron temperature profile on the cross section of a Tokamak, using ECE technique

    Directory of Open Access Journals (Sweden)

    M. Hosseinpour

    2007-06-01

    Full Text Available  In this paper we have used plasma electron cyclotron emissions at the second harmonic frequency of extraordinary mode to determine the temperature profile of the plasma produced in IR-T1 Tokamak. The emissions obtained at different frequencies by a 5-channel heterodyne receiver, have been analyzed to determine the spatial variation of the electron temperature on the plasma cross section. The results have been also used to show the three-dimensional time evolution of the temperature profile during the period of confinement.

  3. Optical excitation cross-sections for electron collisions with atoms and molecules

    International Nuclear Information System (INIS)

    McConkey, J.W.; Univ. of Windsor, Ontario)

    1983-01-01

    A brief review of the status of absolute electron-impact excitation cross-section measurements for atoms and molecules is presented. Some of the reasons for the wide discrepancies which exist in the published data are discussed. Tables are presented of recent publications in the field which are not included in the J.I.L.A. compilations. A tabular compilation of the existing data for e-impact on H 2 O is also given and discussed. Some recent experiments of particular interest to the development of the theory of electron-molecule excitation are mentioned. 112 references, 3 figures, 3 tables

  4. Differential cross sections for inelastic scattering of electrons on Kr and Xe atoms at intermediate energies

    International Nuclear Information System (INIS)

    Filipovic, D.M.

    1989-01-01

    Electron-impact excitation of the larger- number noble-gas atoms is a way of understanding excitation mechanisms in atomic collisional processes. Krypton and xenon have the largest atomic number of all the stable noble gases. Therefore, effects dependent on the size of a target atom, such as alignment and orientation of the atomic outer shell charge cloud after collisional excitation, are best observed by studying these atoms. Normalized, absolute differential cross sections (DCS's) for the lowest electronic states of Kr and Xe atoms, at intermediate energies, are the subject of this report

  5. Calculation of total cross sections for electron and positron scattering on sodium and potassium

    International Nuclear Information System (INIS)

    McCarthy, I.E.; Ratnavelu, K.; Zhou, Y.

    1993-02-01

    Total cross sections for electron and positron scattering on sodium and potassium are calculated at various energies and compared with experiment. The method use is the coupled-channels-optical method with the equivalent-local polarisation potential, which takes all channels into account. For electrons the calculations are checked by comparison with coupled-channels-optical calculations using a detailed polarisation potential that makes only one approximation, that of weak coupling in the ionisation space. The polarisation potential for positrons includes effects of ionisation and positronium formation. 13 refs., 2 tabs

  6. The effective differential cross section for elastic scattering of electrons by atoms and its use for Monte Carlo simulation of electron passage through matter

    International Nuclear Information System (INIS)

    Sheikin, E G

    2010-01-01

    The effective differential cross section (DCS) for elastic scattering of electrons by atoms is proposed that reproduces known energy dependences for the first and second transport cross sections but provides a total elastic cross section that is significantly small compared with the known energy dependences. The number of elastic collisions of electrons in matter when using the effective DCS in Monte Carlo simulations is significantly lower than that when using the real DCS. The results of our Monte Carlo simulation of electron propagation in aluminium using the proposed DCS are in good agreement with experimental data.

  7. Use of electronic cigarettes among Romanian university students: a cross-sectional study.

    Science.gov (United States)

    Lotrean, Lucia Maria

    2015-04-11

    Because electronic cigarettes are relatively new, data on usage patterns and factors which influence them are sparse. Hence, this study aims at assessing awareness, beliefs about electronic cigarettes and experimentation with them among university students from Romania- a country where the sales and marketing of these products are widespread. Secondly, correlates of electronic cigarette experimentation will also be investigated. A cross-sectional study was performed by means of anonymous questionnaires among 480 students, aged 19-24, from Cluj-Napoca, Romania, between April-May 2013. The results show that 92.5% of the students have heard about e-cigarettes; out of these, one quarter (53.3% of the smokers, 25% of the ex-smokers, 5.5% of the non-smokers) have tried electronic cigarettes at least once during lifetime. The results of the multinomial logistic regression point out that the correlates of electronic cigarette experimentation were: male gender, being a smoker of traditional cigarettes, having friends who experimented with electronic cigarettes, having stronger beliefs that electronic cigarettes could help them quit smoking and being less convinced that they are used only by smokers. The explained variance was 59%. The results underline the importance of addressing the issue of e-cigarette use through health education programs and regulatory interventions, since e-cigarettes are a reality faced by the Romanian youth.

  8. Communicating Ebola through social media and electronic news media outlets: A cross-sectional study.

    Science.gov (United States)

    Househ, Mowafa

    2016-09-01

    Social media and electronic news media activity are an important source of information for the general public. Yet, there is a dearth of research exploring the use of Twitter and electronic news outlets during significant worldly events such as the recent Ebola Virus scare. The purpose of this article is to investigate the use of Twitter and electronic news media outlets in communicating Ebola Virus information. A cross-sectional survey of Twitter data and Google News Trend data from 30 September till 29 October, 2014 was conducted. Between 30 September and 29 October, there were approximately 26 million tweets (25,925,152) that contained the word Ebola. The highest number of correlated activity for Twitter and electronic news outlets occurred on 16 October 2014. Other important peaks in Twitter data occurred on 1 October, 6 October, 8 October, and 12 October, 2014. The main influencers of the Twitter feeds were news media outlets. The study reveals a relationship between electronic news media publishing and Twitter activity around significant events such as Ebola. Healthcare organizations should take advantage of the relationship between electronic news media and trending events on social media sites such as Twitter and should work on developing social media campaigns in co-operation with leading electronic news media outlets (e.g. CNN, Yahoo, Reuters) that can have an influence on social media activity. © The Author(s) 2015.

  9. Crossing rule for a PT-symmetric two-level time-periodic system

    International Nuclear Information System (INIS)

    Moiseyev, Nimrod

    2011-01-01

    For a two-level system in a time-periodic field we show that in the non-Hermitian PT case the level crossing is of two quasistationary states that have the same dynamical symmetry property. At the field's parameters where the two levels which have the same dynamical symmetry cross, the corresponding quasienergy states coalesce and a self-orthogonal state is obtained. This situation is very different from the Hermitian case where a crossing of two quasienergy levels happens only when the corresponding two quasistationary states have different dynamical symmetry properties and, unlike the situation in the non-Hermitian case, the spectrum remains complete also when the two levels cross.

  10. Single-Molecule Electronics with Cross- Conjugated Molecules: Quantum Interference, IETS and Non-Equilibrium "Temperatures"

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo

    Abstract The idea of using single-molecules as components in electronic devices is fas- cinating. For this idea to come into fruition, a number of technical and theo- retical challenges must be overcome. In this PhD thesis, the electron-phonon interaction is studied for a special class of molecules......, which is characterised by destructive quantum interference. The molecules are cross-conjugated, which means that the two parts of the molecules are conjugated to a third part, but not to each other. This gives rise to an anti-resonance in the trans- mission. In the low bias and low temperature regime......-conjugated molecules. We nd that the vibrational modes that would be expected to dominate, following the propensity, rules are very weak. Instead, other modes are found to be the dominant ones. We study this phenomenon for a number of cross-conjugated molecules, and link these ndings to the anti...

  11. Integrated cross sections for the ionisation of atomic hydrogen by electron impact

    International Nuclear Information System (INIS)

    Konovalov, D.A.; McCarthy, I.E.

    1992-05-01

    Distorted-wave Born approximation (DWBA) calculations are reported for singly-differential and total cross sections for the electron impact ionisation for atomic hydrogen at 25, 40, 60, 100, 150 and 250 eV. The theory is compared with available experiments. At all the energies except 25 eV the theory predicts a lower singly-differential cross section for the low-energy side of the secondary-electron energies (<5 eV), compared to the only available absolute measurements of Shyn (1992). The DWBA calculation is in good agreement with the experiment at 25 eV but only if e-e post-collision interaction is included in the theory in some way. 23 refs., 2 figs

  12. Total cross section for chloroflouromethanes and CClx radicals by electron impact

    International Nuclear Information System (INIS)

    Gupta, Dhanoj; Antony, Bobby

    2013-01-01

    Highlights: ► A model to find total CS for freons and CCl x by e − impact is employed. ► Complex optical potential formalism is used to find total inelastic and elastic CS. ► Result shows very good agreement with previous data wherever available. ► Maiden attempt to find cross section for the CCl x radicals. -- Abstract: We report here the total cross section for chloroflouromethanes namely CCl 3 F (Freon 11), CCl 2 F 2 (Freon 12), CClF 3 (Freon 13), CCl 4 and CCl x (x = 1–3), radicals by electron impact 50 to 5000 eV. The total inelastic and elastic cross sections are obtained employing a complex optical potential formalism and solving the Schrödinger equation through partial wave analysis. The total cross section is obtained as the sum of total inelastic and elastic cross sections. The results obtained are compared with the existing experimental and theoretical data, wherever available. The present result shows reasonable agreement with previous data. For the CCl x radicals, we have predicted the total cross sections for the first time. The data reported here has immense interest to atmospheric and technological plasma modelling

  13. Singly differential electron emission cross sections for ionization of helium by protons

    International Nuclear Information System (INIS)

    Barna, I.F.; Gagyi-Palffy, A.C.; Gulyas, L.; Tokesi, K.; Burgdoerfer, J.

    2005-01-01

    Angular differential cross sections are calculated for electrons emitted in proton-helium collisions within the framework of the time-dependent coupled channel-method. The channel wave functions are constructed from Slater functions and Coulomb wave packets. As projectiles we consider protons with energies between 0.3 and 1.5 MeV. We compare our results with experimental data and other theoretical calculations using the first Born approximation, different distorted wave models and classical trajectory Monte Carlo simulations

  14. Associations of attitudes towards electronic cigarettes with advertisement exposure and social determinants: a cross sectional study

    OpenAIRE

    Reinhold, Benjamin; Fischbein, Rebecca; Bhamidipalli, Surya Sruthi; Bryant, Jennifer; Kenne, Deric R.

    2017-01-01

    Background The exposure of young adults to electronic cigarette (e-cigarette) advertisements has risen rapidly. E-cigarette ads have been shown to increase short term perceived acceptability of using e-cigarettes in places where traditional cigarettes are banned. We set out to investigate if advertising exposure was related to perceptions of harm, addictiveness, and acceptability of use of e-cigarettes in places where traditional cigarettes are banned. Methods Using a cross-sectional design, ...

  15. Partial and total electronic stopping cross sections of atoms and solids for protons

    International Nuclear Information System (INIS)

    Kaneko, Toshiaki.

    1990-12-01

    Based on a wave packet theory (Phys. Rev. A40, 2188(1989); Phys. Stat. Sol. (B)156,49(1989)), partial and total electronic cross sections of target elements in atomic and solid phases with atomic number Z ranging from 2 (He) to 92 (U) are tabulated shell by shell for protons with velocity v from 0.2V 0 to 2OV 0 (V 0 =2.18 x 10 8 cm/s). (author)

  16. The Evolution of the Electronics Industry in the SIJORI Cross-border Region

    OpenAIRE

    van Grunsven, Leo; Hutchinson, F.

    2014-01-01

    In the early 1990s, Singapore, the Malaysian state of Johor, and the Indonesian island of Batam sought to leverage their proximity, differing comparative advantages, and good logistics connections to market themselves as an integrated unit. After an initial phase of enthusiasm and considerable investment from electronics multinationals, attention regarding the cross-border region waned in the wake of the Asian Financial Crisis. Using data from investment authorities in Indonesia and Malaysia,...

  17. Absolute 3PO triple differential cross sections for electron-helium Wannier threshold ionisation

    International Nuclear Information System (INIS)

    Carruthers, D.R.J.; Crothers, D.S.F.

    1992-01-01

    The uniform semiclassical approximation of Crothers is employed to find a final-state 3 P O wave function for threshold electron impact ionisation of helium. The Kohn variational principle is applied perturbatively to evaluate the scattering amplitude and hence the absolute 3 P O contribution to the triple differential cross sections. These plus the previous absolute singlet results of Crothers are compared favourably with the relative experimental results of Selles et al. (orig.)

  18. Experimental cross sections for the pickup of electrons by relativistic nuclei

    International Nuclear Information System (INIS)

    Raisbeck, G.M.; Crawford, H.J.; Lindstroem, P.J.; Greiner, D.E.; Beiser, F.S.; Heckman, H.H.

    1977-01-01

    Cross sections for the pickup of electrons in a variety of targets have been measured with beams of 12 C (150, 250, 400 MeV/n), 20 Ne (250, 400, 1050, 2100 MeV/n) and 40 Ar (400, 1050 MeV/n) from the Bevalac accelerator. The interpretation of the results in terms of radiative and non-radiative capture, and the implications for cosmic ray propagation studies are discussed. (author)

  19. Evaluating uncertainties in the cross-calibration of parallel ion chambers used in electron beam radiotherapy

    International Nuclear Information System (INIS)

    Anderson, Ernani; Travassos, Paulo; Ferreira, Max da Silva; Carvalho, Samira Marques de; Silva, Michele Maria da; Peixoto, Jose Guilherme Pereira; Salmon Junior, Helio Augusto

    2015-01-01

    This study aims to estimative the combined standard uncertainty for a detector parallel plate used for dosimetry of electron beams in linear accelerators for radiotherapy, which has been calibrated by the cross-calibration method. Keeping the combined standard uncertainty next of the uncertainty informed in the calibration certificate of the reference chamber, become possible establish the calibration factor of the detector. The combined standard uncertainty obtained in this study was 2.5 %. (author)

  20. Comparison of inelastic electron and positron scattering cross sections on 12C and 27Al

    International Nuclear Information System (INIS)

    Hartwig, S.; Heimlich, F.H.; Huber, G.; Roessle, E.; Koebberling, M.; Moritz, J.; Schmidt, K.H.; Wegener, D.; Zeller, D.; Bleckwenn, J.

    1977-06-01

    The +/- ratio R of the cross sections for inelastic positron and electron scattering on 12 C and 27 Al has been measured for four momentum transfers (0.08 - 0.45) GeV 2 /c 2 of the virtual photon and invariant masses 0.95 GeV +- 0.0007), no q 2 respectively W dependence of the ratio is observed. (orig.) [de

  1. 0.1–2000 eV electron impact cross sections for dichlorine monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, Biplab; Gupta, Dhanoj; Antony, Bobby, E-mail: bka.ism@gmail.com

    2014-03-01

    Highlights: • Quantum mechanical models were used to find TCS for e-Cl{sub 2}O from 0.1 to 2000 eV. • R-matrix method at low energies (<13 eV) and SCOP at high energies (13–2000 eV). • Besides TCS, DCS, excitation cross section and momentum transfer CS also predicted. • R-matrix method identifies resonances with a possibility of DEA formation. • Resonance detected at 1.88 eV is associated with Cl{sub 2}O{sup −} anion formation. - Abstract: Scattering dynamics of dichlorine monoxide (Cl{sub 2}O) molecule by electron impact is investigated as a function of electron energy and scattering angle. Electron impact total cross sections for Cl{sub 2}O over an extensive range of impact energies from 0.1 to 2000 eV are reported in this article. Below the ionization threshold of the target, the ab initio R-matrix method and above this incident energy spherical complex optical potential formalism are used for cross section calculation. The total cross section obtained from both theories merges smoothly at the overlapping energy. The resonances obtained using DZP basis sets are located at 1.883, 3.592, 5.205 and 7.326, 8.206, 8.301, 8.452, 9.369 eV and that with 6-31G* basis sets are identified at 1.944, 3.566, 5.183, 5.261, 5.658, 8.738 and 9.187 eV with the possibility of negative ions formation. This is the first attempt to calculate the differential, and momentum transfer cross sections for Cl{sub 2}O molecule.

  2. Bibliography of electron and photon cross sections with atoms and molecules. Published in the 20th century. Methane

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2004-10-01

    Bibliographies of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for methane (CH 4 ). About 1050 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1924 through 2000 for CH 4 . Finally, author's comments for CH 4 electron collision cross sections are given. (author)

  3. 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.

  4. Cross sections for electron-impact excitation of the H2 molecule using the MOB-SCI strategy

    International Nuclear Information System (INIS)

    Costa, Romarly F da; Paixao, Fernando J da; Lima, Marco A P

    2005-01-01

    In this paper, we report integral and differential cross sections for the electronic excitation of H 2 molecules by electron-impact. Our scattering amplitudes were calculated using the Schwinger multichannel method within the minimal orbital basis for single configuration interactions (MOB-SCI) level of approximation. Through the use of the present strategy we have investigated the coupling effects among ground state and first singlet and triplet states of the same spatial symmetry. The five-state (nine for degenerated states) close-coupling calculations joined the advantages of a well-described set of physical states of interest with a minimum associated pseudo-state space. The results obtained by means of the MOB-SCI technique show a significant improvement towards experimental data in comparison with previous two-channel close-coupling calculations

  5. Absolute total and partial dissociative cross sections of pyrimidine at electron and proton intermediate impact velocities

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Wania, E-mail: wania@if.ufrj.br; Luna, Hugo; Sigaud, Lucas; Montenegro, Eduardo C. [Instituto de Física, Universidade Federal do Rio de Janeiro, PO 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Tavares, Andre C. [Departamento de Física, Pontificia Universidade Católica do Rio de Janeiro, PO 38071, Rua Marquês de São Vicente 225, 22453-900 Rio de Janeiro, RJ (Brazil)

    2014-02-14

    Absolute total non-dissociative and partial dissociative cross sections of pyrimidine were measured for electron impact energies ranging from 70 to 400 eV and for proton impact energies from 125 up to 2500 keV. MOs ionization induced by coulomb interaction were studied by measuring both ionization and partial dissociative cross sections through time of flight mass spectrometry and by obtaining the branching ratios for fragment formation via a model calculation based on the Born approximation. The partial yields and the absolute cross sections measured as a function of the energy combined with the model calculation proved to be a useful tool to determine the vacancy population of the valence MOs from which several sets of fragment ions are produced. It was also a key point to distinguish the dissociation regimes induced by both particles. A comparison with previous experimental results is also presented.

  6. Temperature dependence of the cross section for the fragmentation of thymine via dissociative electron attachment

    Energy Technology Data Exchange (ETDEWEB)

    Kopyra, Janina [Faculty of Science, Siedlce University, 3 Maja 54, 08-110 Siedlce (Poland); Abdoul-Carime, Hassan, E-mail: hcarime@ipnl.in2p3.fr [Université de Lyon, Université Claude Bernard Lyon1, Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France)

    2015-05-07

    Providing experimental values for absolute Dissociative Electron Attachment (DEA) cross sections for nucleobases at realistic biological conditions is a considerable challenge. In this work, we provide the temperature dependence of the cross section, σ, of the dehydrogenated thymine anion (T − H){sup −} produced via DEA. Within the 393-443 K temperature range, it is observed that σ varies by one order of magnitude. By extrapolating to a temperature of 313 K, the relative DEA cross section for the production of the dehydrogenated thymine anion at an incident energy of 1 eV decreases by 2 orders of magnitude and the absolute value reaches approximately 6 × 10{sup −19} cm{sup 2}. These quantitative measurements provide a benchmark for theoretical prediction and also a contribution to a more accurate description of the effects of ionizing radiation on molecular medium.

  7. Boltzmann equation analysis of electron-molecule collision cross sections in water vapor and ammonia

    International Nuclear Information System (INIS)

    Yousfi, M.; Benabdessadok, M.D.

    1996-01-01

    Sets of electron-molecule collision cross sections for H 2 O and NH 3 have been determined from a classical technique of electron swarm parameter unfolding. This deconvolution method is based on a simplex algorithm using a powerful multiterm Boltzmann equation analysis established in the framework of the classical hydrodynamic approximation. It is well adapted for the simulation of the different classes of swarm experiments (i.e., time resolved, time of flight, and steady state experiments). The sets of collision cross sections that exist in the literature are reviewed and analyzed. Fitted sets of cross sections are determined for H 2 O and NH 3 which exhibit features characteristic of polar molecules such as high rotational excitation collision cross sections. The hydrodynamic swarm parameters (i.e., drift velocity, longitudinal and transverse diffusion coefficients, ionization and attachment coefficients) calculated from the fitted sets are in excellent agreement with the measured ones. These sets are finally used to calculate the transport and reaction coefficients needed for discharge modeling in two cases of typical gas mixtures for which experimental swarm data are very sparse or nonexistent (i.e., flue gas mixtures and gas mixtures for rf plasma surface treatment). copyright 1996 American Institute of Physics

  8. Preliminary analysis of LED enhanced signs at a passive rural level crossing

    Science.gov (United States)

    2015-03-23

    The purpose of this research was to measure motor vehicle speed profiles at a rural level crossing following the replacement of the existing Crossbuck signs and Advance Warning signs (AWSs) with flashing light-emitting diode (LED) versions. Measureme...

  9. Triple differential cross section for the ionization of helium by electronic impact

    Energy Technology Data Exchange (ETDEWEB)

    Diallo, Saidou, E-mail: saidou40@yahoo.fr [Laboratoire de Physique des Plasmas et de Recherches Interdisciplinaires, Universite Cheikh Anta Diop, Faculte des Sciences et Techniques, Departement de Physique, BP: 5005 Dakar-Fann (Senegal); Faye, I.G.; Diedhiou, I.A.; Tall, M.S.; Gomis, L.; Diatta, C.S. [Laboratoire de Physique des Plasmas et de Recherches Interdisciplinaires, Universite Cheikh Anta Diop, Faculte des Sciences et Techniques, Departement de Physique, BP: 5005 Dakar-Fann (Senegal)

    2011-12-01

    We report results of analytical triple differential cross sections (TDCS) for the single ionization of the helium iso-electronic ions by the electron impact. A two variational parameters wave function is used to evaluate the TDCS. This study shows the accuracy of the TDCS for helium atom and helium like ions in the first Born approximation (FBA) at high incident energy domain. The theory is quite acceptable as a fast calculation of the triple differential cross section, particularly at high energies where other theories and methods are cumbersome. A comparison is made of our calculations with previous results of the other theoretical methods and experiment. The FBA results obtained here with the two variational parameters wave function are in good agreement with the experiment data at high incident energy. The results show that the electron correlation effects are important around the maxima and influence only the extrema magnitude but not their positions. The calculations presented here are extanded to the cases where the energies of the outgoing electrons are more equal.

  10. Cross sections and oscillator strengths for electron-impact excitation of electronic states in polyatomic molecules. Application examples of the BEf- scaling model in optically-allowed transitions

    International Nuclear Information System (INIS)

    Kato, H.; Kawahara, H.; Hoshino, M.

    2009-12-01

    Integral cross sections for optically allowed electronic-state excitations by electron impact, are reviewed for polyatomic molecules by applying the Binary-Encounter-Bethe (BEB) scaling model. Following the context of the present review, the scaling model originally proposed by Yong-Ki Kim to determine electron-impact cross sections for ionization of atoms and molecules is also summarized briefly for its wide range of applications [Electron-Impact Cross Section Database, NIST, Y.-K. Kim]. The present report not only focuses on the need for the cross-section data, but also elucidates the verification of the scaling model in the general application for atoms and molecules. Since this report is for a data base, it is summarized for data base users by citing (copying) the descriptions in the original papers and the references within those papers in the style of a textbook. (author)

  11. Electron impact ionization of B-like ion N2+. Resonance enhancement of the single-channel cross section

    International Nuclear Information System (INIS)

    Li Guohe; Qian Xingzhong; Pan Soufu

    1998-01-01

    The electron impact ionization cross sections of B-like ion N 2+ are calculated in the Coulomb-Born no exchange approximation by using R-matrix method, and the single differential cross section is given. The calculated results exhibit the Rydberg series of resonances. The resonance enhancement of the single-channel cross section is significantly greater than direct ionization cross section. It is agreement with that of Chidichimo

  12. Cross effects on electron-cyclotron and lower-hybrid current drive in tokamak plasmas

    International Nuclear Information System (INIS)

    Fidone, I.; Giruzzi, G.; Krivenski, V.; Mazzucato, E.; Ziebell, L.F.

    1986-11-01

    Electron cyclotron resonance current drive in a tokamak plasma in the presence of a lower hybrid tail is investigated using a 2D Fokker-Planck code. For an extraordinary mode at oblique propagation and down-shifted frequency it is shown that the efficiency of electron cyclotron current drive becomes, i) substantially greater than the corresponding efficiency of a Maxwellian plasma at the same bulk temperature, ii) equal or greater than that of the lower hybrid waves, iii) comparable with the efficiency of a Maxwellian plasma at much higher temperature. This enhancement results from a beneficial cross-effect of the two waves on the formation of the current carrying electron tail. (5 fig; 17 refs)

  13. Cross-section measurements for the fragmentation of CHClF{sub 2} by electron impact

    Energy Technology Data Exchange (ETDEWEB)

    Sigaud, L; Ferreira, Natalia; Wolff, W; Santos, A C F dos; Montenegro, E C [Instituto de FIsica, Universidade Federal do Rio de Janeiro, PO 68528, 21941-972 Rio de Janeiro, RJ (Brazil); De Jesus, V L B; Menezes, R S [Instituto Federal de Educacao, Ciencia e Tecnologia do Rio de Janeiro (IFRJ), Campus Nilopolis, R. Lucio Tavares 1045, 26530-060 Nilopolis, RJ (Brazil); De Barros, A L F [CEFET/RJ, Av. Maracana 229, 20271-110 Rio de Janeiro, RJ (Brazil); Rocha, A B [Instituto de QuImica, Universidade Federal do Rio de Janeiro, Cidade Universitaria-Ilha do Fundao, 21941-614 Rio de Janeiro, RJ (Brazil); Shah, M B, E-mail: lucas@if.ufrj.b [School of Maths and Physics, The Queen' s University of Belfast, University Road. Belfast, BT7 1NN (United Kingdom)

    2010-05-28

    CFC compounds present in the upper atmosphere have a significant effect on the environment, strongly contributing to the increase of the hole in the ozone layer. Recent studies show that low-energy electron impact is an important process in the dissociation of these molecules, creating atomic chlorine, which breaks down ozone molecules. In this work, the CHClF{sub 2} fragmentation by electron impact in the 40-400 eV energy range is measured. Total and partial cross sections have been obtained, showing the predominance of the release of neutral chlorine, which amounts to around 60% of the total yield. There is a strong indication that this chlorine is being released as a result of the ionization of electrons from both chlorine and fluorine orbitals.

  14. Experimental and theoretical double differential cross sections for electron impact ionization of methane

    Energy Technology Data Exchange (ETDEWEB)

    Yavuz, Murat; Ozer, Zehra Nur, E-mail: zehraerengil@aku.edu.tr; Ulu, Melike; Dogan, Mevlut [e-COL Laboratory, Department of Physics, Afyon Kocatepe University, Afyonkarahisar 03200 (Turkey); Champion, Christophe [Centre d’Etudes Nucléaires de Bordeaux Gradignan, CNRS/IN2P3, Université de Bordeaux, Gradignan 33170 (France)

    2016-04-28

    Experimental and theoretical double differential cross sections (DDCSs) for electron-induced ionization of methane (CH{sub 4}) are here reported for primary energies ranging from 50 eV to 350 eV and ejection angles between 25° and 130°. Experimental DDCSs are compared with theoretical predictions performed within the first Born approximation Coulomb wave. In this model, the initial molecular state is described by using single center wave functions, the incident (scattered) electron being described by a plane wave, while a Coulomb wave function is used for modeling the secondary ejected electron. A fairly good agreement may be observed between theory and experiment with nevertheless an expected systematic overestimation of the theory at low-ejection energies (<50 eV).

  15. Evaluation of computational models and cross sections used by MCNP6 for simulation of electron backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Poškus, Andrius, E-mail: andrius.poskus@ff.vu.lt

    2016-02-01

    This work evaluates the accuracy of the single-event (SE) and condensed-history (CH) models of electron transport in Monte Carlo simulations of electron backscattering from thick layers of Be, C, Al, Cu, Ag, Au and U at incident electron energies from 200 eV to 15 MeV. The CH method is used in simulations performed with MCNP6.1, and the SE method is used in simulations performed with an open-source single-event code MCNelectron written by the author of this paper. Both MCNP6.1 and MCNelectron use mainly ENDF/B-VI.8 library data, but MCNelectron allows replacing cross sections of certain types of interactions by alternative datasets from other sources. The SE method is evaluated both using only ENDF/B-VI.8 cross sections (the “SE-ENDF/B method”, which is equivalent to using MCNP6.1 in SE mode) and with an alternative set of elastic scattering cross sections obtained from relativistic (Dirac) partial-wave (DPW) calculations (the “SE-DPW method”). It is shown that at energies from 200 eV to 300 keV the estimates of the backscattering coefficients obtained using the SE-DPW method are typically within 10% of the experimental data, which is approximately the same accuracy that is achieved using MCNP6.1 in CH mode. At energies below 1 keV and above 300 keV, the SE-DPW method is much more accurate than the SE-ENDF/B method due to lack of angular distribution data in the ENDF/B library in those energy ranges. At energies from 500 keV to 15 MeV, the CH approximation is roughly twice more accurate than the SE-DPW method, with the average relative errors equal 7% and 14%, respectively. The energy probability density functions (PDFs) of backscattered electrons for Al and Cu, calculated using the SE method with DPW cross sections when energy of incident electrons is 20 keV, have an average absolute error as low as 4% of the average PDF. This error is approximately twice less than the error of the corresponding PDF calculated using the CH approximation. It is concluded

  16. CVTresh: R Package for Level-Dependent Cross-Validation Thresholding

    Directory of Open Access Journals (Sweden)

    Donghoh Kim

    2006-04-01

    Full Text Available The core of the wavelet approach to nonparametric regression is thresholding of wavelet coefficients. This paper reviews a cross-validation method for the selection of the thresholding value in wavelet shrinkage of Oh, Kim, and Lee (2006, and introduces the R package CVThresh implementing details of the calculations for the procedures. This procedure is implemented by coupling a conventional cross-validation with a fast imputation method, so that it overcomes a limitation of data length, a power of 2. It can be easily applied to the classical leave-one-out cross-validation and K-fold cross-validation. Since the procedure is computationally fast, a level-dependent cross-validation can be developed for wavelet shrinkage of data with various sparseness according to levels.

  17. CVTresh: R Package for Level-Dependent Cross-Validation Thresholding

    Directory of Open Access Journals (Sweden)

    Donghoh Kim

    2006-04-01

    Full Text Available The core of the wavelet approach to nonparametric regression is thresholding of wavelet coefficients. This paper reviews a cross-validation method for the selection of the thresholding value in wavelet shrinkage of Oh, Kim, and Lee (2006, and introduces the R package CVThresh implementing details of the calculations for the procedures.This procedure is implemented by coupling a conventional cross-validation with a fast imputation method, so that it overcomes a limitation of data length, a power of 2. It can be easily applied to the classical leave-one-out cross-validation and K-fold cross-validation. Since the procedure is computationally fast, a level-dependent cross-validation can be developed for wavelet shrinkage of data with various sparseness according to levels.

  18. Measurements of absolute M-subshell X-ray production cross sections of Th by electron impact

    Energy Technology Data Exchange (ETDEWEB)

    Moy, A., E-mail: aurelien.moy@cea.fr [GM, CNRS, Université de Montpellier II, Place E. Bataillon, F-34095 Montpellier (France); CEA, DEN, DTEC, SGCS, LMAC, F-30207 Bagnols-sur-Cèze (France); Merlet, C. [GM, CNRS, Université de Montpellier II, Place E. Bataillon, F-34095 Montpellier (France); Dugne, O. [CEA, DEN, DTEC, SGCS, LMAC, F-30207 Bagnols-sur-Cèze (France)

    2014-08-31

    Highlights: • The M X-ray production cross sections of Th were measured by electron impact. • The M-subshell ionization cross sections of Th were determined from 3 to 38 keV. • Theoretical ionization cross-sections are in agreement with our experimental results. - Abstract: Measurements of absolute M-subshell X-ray production cross sections for element Th were made by electron impact for energies ranging from the ionization threshold up to 38 keV. Experimental data were obtained by measuring the X-ray intensity emitted from ultrathin Th films deposited onto self-supporting C backing films. The measurements were conducted with an electron microprobe using high-resolution wavelength dispersive spectrometers. Recorded intensities were converted into absolute X-ray production cross sections by means of atomic data and estimation of the number of primary electrons, target thickness, and detector efficiency. Our experimental X-ray production cross sections, the first to be reported for the M subshells of Th, are compared with X-ray production cross sections calculated with the mean of ionization cross sections obtained from the distorted-wave Born approximation. The Mα X-ray production cross section calculated is in excellent agreement with the measurements, allowing future use for standardless quantification in electron probe microanalysis.

  19. Angle-resolving time-of-flight electron spectrometer for near-threshold precision measurements of differential cross sections of electron-impact excitation of atoms and molecules

    International Nuclear Information System (INIS)

    Lange, M.; Matsumoto, J.; Setiawan, A.; Panajotovic, R.; Harrison, J.; Lower, J. C. A.; Newman, D. S.; Mondal, S.; Buckman, S. J.

    2008-01-01

    This article presents a new type of low-energy crossed-beam electron spectrometer for measuring angular differential cross sections of electron-impact excitation of atomic and molecular targets. Designed for investigations at energies close to excitation thresholds, the spectrometer combines a pulsed electron beam with the time-of-flight technique to distinguish between scattering channels. A large-area, position-sensitive detector is used to offset the low average scattering rate resulting from the pulsing duty cycle, without sacrificing angular resolution. A total energy resolution better than 150 meV (full width at half maximum) at scattered energies of 0.5-3 eV is achieved by monochromating the electron beam prior to pulsing it. The results of a precision measurement of the differential cross section for electron-impact excitation of helium, at an energy of 22 eV, are used to assess the sensitivity and resolution of the spectrometer

  20. s-wave threshold in electron attachment - Observations and cross sections in CCl4 and SF6 at ultralow electron energies

    Science.gov (United States)

    Chutjian, A.; Alajajian, S. H.

    1985-01-01

    The threshold photoionization method was used to study low-energy electron attachment phenomena in and cross sections of CCl4 and SF6 compounds, which have applications in the design of gaseous dielectrics and diffuse discharge opening switches. Measurements were made at electron energies from below threshold to 140 meV at resolutions of 6 and 8 meV. A narrow resolution-limited structure was observed in electron attachment to CCl4 and SF6 at electron energies below 10 meV, which is attributed to the divergence of the attachment cross section in the limit epsilon, l approaches zero. The results are compared with experimental collisional-ionization results, electron-swarm unfolded cross sections, and earlier threshold photoionization data.

  1. Resolved nuclear hyperfine structure of muonium in CuCl by means of muon level-crossing resonance

    International Nuclear Information System (INIS)

    Schneider, J.W.; Keller, H.; Odermatt, W.; Puempin, B.; Savic, I.M.; Simmler, H.; Dodds, S.A.; Estle, T.L.; Duvarney, R.C.; Chow, K.; Kadono, R.; Kiefl, R.F.; Li, Q.; Riseman, T.M.; Zhou, H.; Lichti, R.L.; Schwab, C.

    1991-01-01

    Detailed muon level-crossing resonance measurements of Mu I and Mu II centres in single crystals of CuCl are presented. The hyperfine and nuclear hyperfine parameters of the closest two shells of nuclei are remarkably similar for the two centres, indicating that both are located at the same tetrahedral interstitial site with four Cu nearest neighbours and six Cl next-nearest neighbours. About 30% of the total unpaired-electron spin density is located on the muon, about 60% on the four nearest neighbours and the rest on the six next-nearest neighbours, with nothing observable for any other shell. (orig.)

  2. Production of a high-current microsecond electron beam with a large cross section

    International Nuclear Information System (INIS)

    Abdullin, E.N.; Belomytsev, S.Ya.; Bugaev, S.P.; Gorbachev, S.I.; Zaslavskii, V.M.; Zorin, V.P.; Koval'chuk, B.M.; Loginov, S.V.; Matyukov, Yu.N.; Rasputin, R.M.; Tolkachev, V.S.; Shchanin, P.M.

    1991-01-01

    Obtaining high-current wide-aperture electron beams is an important problem in the development of laser technology for controlled nuclear fusion and for solving ecological and technological problems. The main scheme for producing such beams involves the use of generators with intermediate energy storage devices and burst-emission vacuum diodes. Beam pinching is prevented by using an external magnetic field or sectioning the diode into magnetically insulated diodes with currents lower than the limiting current. The length of the electron-current pulse varies from tens to hundreds of nano-seconds and is limited by the parameters of the intermediate storage device. Here the authors study the formation of a high-current electron beam with a square cross section and a current of the order of the limiting current of the diode in the absence of an external magnetic field as well as a 'fast' storage device in the power supply circuit. These conditions as a whole correspond to a simpler electron-source circuit, but the beam forming becomes more complicated. The reason for this is that there is no external magnetic field and that the role of plasma processes in the diode is enhanced by the greater length of the electron-current pulses

  3. Double- and triple-differential cross sections for electron-impact ionization of helium

    International Nuclear Information System (INIS)

    Biswas, R.; Sinha, C.

    1995-01-01

    Triple- (TDCS) and double- (DDCS) differential cross sections have been calculated for single ionization in electron-helium collisions for asymmetric geometry at intermediate and medium high energies. The TDCS and DDCS results have been presented for different kinematical situations and have been compared with the corresponding experiments. In the present prescription, the final-state wave function involves the correlation between the two continuum electrons and satisfies the three-body asymptotic boundary condition (for asymmetric geometry), which is an important criterion for reliable ionization cross sections. The sensitivity of the ionization cross sections (particularly of the TDCS) with respect to the choice of the bound-state wave function of the He atom has also been studied, using two different forms of wave function of the He atom. The binary-to-recoil peak intensity ratio against momentum transfer in TDCS is found to be in closer agreement with the experiment for the simple Hylleraas wave function than for the Hartree-Fock wave function. The DDCS results are found to be in good agreement with the experimental data of Mueller-Fiedler et al. [J. Phys. B 19, 1211 (1986)] for lower ejected energy (E 2 ), while for higher E 2 the results are closer to the measurements of Shyn et al. [Phys. Rev. A 19, 557 (1979)] and Avaldi et al. [Nuovo Cimento D 9, 97 (1987)

  4. Inelastic cross-sections for electron transport in liquid water: a comparison of dielectric models

    International Nuclear Information System (INIS)

    Emfietzoglou, D.

    2003-01-01

    Various methodologies for constructing inelastic cross-sections for low-energy (<10 keV) electron transport in liquid water are presented and compared. They are all based on an optical-data model which provides the dependence on energy loss, and a dispersion algorithm which incorporates the momentum-transfer dependence. A Drude dielectric model was used to analytically represent the optical data. Various dispersion schemes were examined: the Bethe approximation, the δ-oscillator models of Ashley and Liljequist, and two forms of Ritchie's extended-Drude model. They all have been used in Monte-Carlo (MC) codes for analog electron transport in the condensed phase. Results in the form of differential and total inelastic cross-sections are presented. Where possible, comparisons with results of other studies are made. It was found that, despite the application of general constraints (e.g. sum rules), the optical model has a notable influence on the single-collision energy loss spectrum. In addition, both the shape and peak position of the total and differential cross-section distributions depend strongly on the dispersion model adopted. The work is particularly relevant to the development of event-by-event MC transport codes for liquid water, as well as, to the calculations of stopping-powers below the range of applicability of Bethe's formula

  5. Charge-state dependence of binary-encounter-electron cross sections and peak energies

    International Nuclear Information System (INIS)

    Hidmi, H.I.; Richard, P.; Sanders, J.M.; Schoene, H.; Giese, J.P.; Lee, D.H.; Zouros, T.J.M.; Varghese, S.L.

    1993-01-01

    The charge-state dependence of the binary-encounter-electron (BEE) double-differential cross section (DDCS) at 0 degree with respect to the beam direction resulting from collisions of 1 MeV/amu H + , C q+ , N q+ , O q+ , F q+ , Si q+ , and Cl q+ , and 0.5 MeV/amu Cu q+ with H 2 is reported. The data show an enhancement in the BEE DDCS as the charge state of the projectile is decreased, in agreement with the data reported by Richard et al. [J. Phys. B 23, L213 (1990)]. The DDCS enhancement ratios observed for the three-electron isoelectronic sequence C 3+ :C 6+ , N 4+ :N 7+ , O 5+ :O 8+ , and F 6+ :F 9+ are about 1.35, whereas a DDCS enhancement of 3.5 was observed for Cu 4+ . The BEE enhancement with increasing electrons on the projectile has been shown by several authors to be due to the non-Coulomb static potential of the projectile and additionally to the e-e exchange interaction. An impulse-approximation (IA) model fits the shape of the BEE DDCS and predicts a Z p 2 dependence for the bare-ion cross sections. The IA also predicts a binary peak energy that is independent of q and Z p and below the classical value of 4t, where t is the energy of electrons traveling with the projectile velocity. We observed a BEE energy shift ΔE (ΔE=4t-E peak , where E peak is the measured energy at the peak of the binary encounter electrons) that is approximately independent of q for the low-Z p ions, whereas the measured ΔE values for Si, Cl, and Cu were found to be q dependent

  6. Double-continuum wave functions and double-photoionization cross sections of two-electron systems

    International Nuclear Information System (INIS)

    Tiwary, S.N.

    1996-09-01

    The present review briefly presents the growing experimental as well as theoretical interests in recent years in the double-continuum wave functions and double-photoionization cross sections of two-electron systems. The validity of existing double-continuum wave functions is analyzed and the importance of electronic correlations in both the initial as well as final states wave functions involved in the transition amplitude for double-photoionization process is demonstrated. At present, we do not have comprehensive and practical double-continuum wave functions which account the full correlation of two-electron in the continuum. Basic difficulties in making accurate theoretical calculations of double ionization by a single high energy photon especially in the vicinity of the threshold, where the correlation plays an important role, are discussed. Illuminating, illustrative and representative examples are presented in order to show the present status and the progress in this field. Future challenges and directions, in high-precision double-photoionization cross sections calculations, have been discussed and suggested. (author). 133 refs, 9 figs

  7. Quantum-mechanical predictions of electron-induced ionization cross sections of DNA components

    International Nuclear Information System (INIS)

    Champion, Christophe

    2013-01-01

    Ionization of biomolecules remains still today rarely investigated on both the experimental and the theoretical sides. In this context, the present work appears as one of the first quantum mechanical approaches providing a multi-differential description of the electron-induced ionization process of the main DNA components for impact energies ranging from the target ionization threshold up to about 10 keV. The cross section calculations are here performed within the 1st Born approximation framework in which the ejected electron is described by a Coulomb wave whereas the incident and the scattered electrons are both described by a plane wave. The biological targets of interest, namely, the DNA nucleobases and the sugar-phosphate backbone, are here described by means of the GAUSSIAN 09 system using the restricted Hartree-Fock method with geometry optimization. The theoretical predictions also obtained have shown a reasonable agreement with the experimental total ionization cross sections while huge discrepancies have been pointed out with existing theoretical models, mainly developed within a semi-classical framework.

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

    CERN Document Server

    Samson, A M

    2001-01-01

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

  9. Measurement of the hadronic cross section in electron-positron annihilation

    International Nuclear Information System (INIS)

    Clearwater, S.

    1983-11-01

    This thesis describes the most precise measurement to date of the ratio R, the hadronic cross section in lowest order electron-positron annihilation to the cross section for muon pair production in lowest order electron-positron annihilation. This experiment is of interest because R is a fundamental parameter that tests in a model independent way the basic assumptions of strong interaction theories. According to the assumptions of one of these theories the value of R is determined simply from the electric charges, spin, and color assignments of the produced quark-pairs. The experiment was carried out with the MAgnetic Calorimeter using collisions of 14.5 GeV electrons and positrons at the 2200m circumference PEP storage ring at SLAC. The MAC detector is one of the best-suited collider detectors for measuring R due to its nearly complete coverage of the full angular range. The data for this experiment were accumulated between February 1982 and April 1983 corresponding to a total event sample of about 40,000 hadronic events. About 5% of the data were taken with 14 GeV beams and the rest of the data were taken with 14.5 GeV beams. A description of particle interactions and experimental considerations is given

  10. Computation of electron-impact K-shell ionization cross sections of atoms

    International Nuclear Information System (INIS)

    Uddin, M.A.; Haque, A.K.F.; Billah, M. Masum; Basak, A.K.; Karim, K.R.; Saha, B.C.

    2005-01-01

    The total cross sections of electron impact single K-shell ionization of atomic targets, with a wide range of atomic numbers from Z=6-50, are evaluated in the energy range up to about 10 MeV employing the recently proposed modified version of the improved binary-encounter dipole (RQIBED) model [Uddin et al., Phys. Rev. A 70, 032706 (2004)], which incorporates the ionic and relativistic effects. The experimental cross sections for all targets are reproduced satisfactorily even in the relativistic energies using fixed generic values of the two parameters in the RQIBED model. The relativistic effect is found to be significant in all targets except for C, being profound in Ag and Sn

  11. Effect of electron beam-cross-linked gels on the rheological properties of raw natural rubber

    Energy Technology Data Exchange (ETDEWEB)

    Mitra, Suman; Chattopadhyay, Santanu [Rubber Technology Centre, Indian Institute of Technology, Kharagpur, West Bengal 721302 (India); Bharadwaj, Y.K.; Sabharwal, S. [Radiation Technology Development Section, Bhabha Atomic Research Center, Trombay, Mumbai 400085 (India); Bhowmick, Anil K. [Rubber Technology Centre, Indian Institute of Technology, Kharagpur, West Bengal 721302 (India)], E-mail: anilkb@rtc.iitkgp.ernet.in

    2008-05-15

    Electron beam (EB)-cross-linked natural rubber (NR) gels were prepared from latex and characterized by various techniques. The addition of a small amount of these gels to raw NR was found to reduce the apparent shear viscosity and die swell remarkably. This effect was further enhanced with the addition of butyl acrylate as a sensitizer. The apparent shear viscosity first decreased up to 8 phr of gel loading and then increased. However, the percent die swell value decreased steadily upon gel loading. These were explained by calculating principal normal stress difference, the activation energy of melt flow and characteristics of EB-cross-linked gels. These effects were also reflected in the changes of mechanical and dynamic mechanical properties of gel-filled raw NR. Tailoring of the above properties could be done with the help of these gels.

  12. Investigation of the influence of intermolecular interactions on the electronic stopping cross sections

    International Nuclear Information System (INIS)

    Krotz, R.; Neuwirth, W.; Pietsch, W.

    1980-01-01

    The electronic stopping cross sections for Li projectiles have been measured in various kinds of targets. They are analyzed here with respect to the different types of interactions between the constituents of the target: interactions between the atoms in a compound (chemical bonding), the ion-dipole interaction, if the target is an electrolytic solution, and the dipole-dipole interaction among polar molecules. The influence on the stopping cross section depends on the strength of these interactions; it varies from a few percent in the latter case up to 20% and more in a compound. These influences are the largest, if the velocity of the projectile is of the order of the average orbital velocity of the target atoms. (author)

  13. Differential and total cross sections for the ionization of water molecule by electron impact

    International Nuclear Information System (INIS)

    Houamer, S.; Dal Cappello, C.; Mansouri, A.

    2007-01-01

    A theoretical approach is presented to calculate multiply differential and total cross sections of the ionization of H 2 O molecule in the vapour phase. The wave function of the target is described by molecular orbitals consisting of a linear combination of slater type atomic orbitals centered on the heaviest atom which is the oxygen atom in this case. The calculations are carried out in the first Born approximation where the projectile is described by a plane wave while the ejected electron is described by a coulomb wave taking into account its interaction with the residual ion. The spherical average over the Euler solid angle due to the randomly oriented gaseous target molecule is carried out analytically using the rotation matrix properties. The differential and total cross sections are thus evaluated without any special difficulty and compared with experiments and distorted wave calculations. Fair agreements are observed

  14. Electron ionization of open/closed chain isocarbonic molecules relevant in plasma processing: Theoretical cross sections

    International Nuclear Information System (INIS)

    Patel, Umang R.; Joshipura, K. N.; Pandya, Siddharth H.; Kothari, Harshit N.

    2014-01-01

    In this paper, we report theoretical electron impact ionization cross sections from threshold to 2000 eV for isocarbonic open chain molecules C 4 H 6 , C 4 H 8 , C 4 F 6 including their isomers, and closed chain molecules c-C 4 H 8 and c-C 4 F 8 . Theoretical formalism employed presently, viz., Complex Scattering Potential-ionization contribution method has been used successfully for a variety of polyatomic molecules. The present ionization calculations are very important since results available for the studied targets are either scarce or none. Our work affords comparison of C 4 containing hydrocarbon versus fluorocarbon molecules. Comparisons of the present ionization cross sections are made wherever possible, and new ionization data are also presented

  15. Absolute cross sections for the ionization-excitation of helium by electron impact

    Science.gov (United States)

    Bellm, S.; Lower, J.; Weigold, E.; Bray, I.; Fursa, D. V.; Bartschat, K.; Harris, A. L.; Madison, D. H.

    2008-09-01

    In a recent publication we presented detailed experimental and theoretical results for the electron-impact-induced ionization of ground-state helium atoms. The purpose of that work was to refine theoretical approaches and provide further insight into the Coulomb four-body problem. Cross section ratios were presented for transitions leading to excited states, relative to those leading to the ground state, of the helium ion. We now build on that study by presenting individual relative triple-differential ionization cross sections (TDCSs) for an additional body of experimental data measured at lower values of scattered-electron energies. This has been facilitated through the development of new electron-gun optics which enables us to accurately characterize the spectrometer transmission at low energies. The experimental results are compared to calculations resulting from a number of different approaches. For ionization leading to He+(1s2)1S , cross sections are calculated by the highly accurate convergent close-coupling (CCC) method. The CCC data are used to place the relative experimental data on to an absolute scale. TDCSs describing transitions to the excited states are calculated through three different approaches, namely, through a hybrid distorted- wave+R -matrix (close-coupling) model, through the recently developed four-body distorted-wave model, and by a first Born approximation calculation. Comparison of the first- and second-order theories with experiment allows for the accuracy of the different theoretical approaches to be assessed and gives insight into which physical aspects of the problem are most important to accurately model.

  16. Electron-neutral scattering cross sections for CO2: a complete and consistent set and an assessment of dissociation

    International Nuclear Information System (INIS)

    Grofulović, Marija; Alves, Luís L; Guerra, Vasco

    2016-01-01

    This work proposes a complete and consistent set of cross sections for electron collisions with carbon dioxide (CO 2 ) molecules to be published in the IST-Lisbon database with LXCat. The set is validated from the comparison between swarm parameters calculated using a two-term Boltzmann solver and the available experimental data. The importance of superelastic collisions with CO 2 (0 1 0) molecules at low values of the reduced electric field is discussed. Due to significant uncertainties, there are ongoing debates regarding the deconvolution of cross sections that describe generic energy losses at specific energy thresholds into cross sections that describe individual processes. An important example of these uncertainties is with the dissociation of CO 2 , for which the total electron impact dissociation cross section has not yet been unambiguously identified. The available dissociation cross sections are evaluated and discussed, and a strategy to obtain electron-impact dissociation rate coefficients is suggested. (paper)

  17. Calculated sputtering and atomic displacement cross-sections for applications to medium voltage analytical electron microscopy

    International Nuclear Information System (INIS)

    Bradley, C.R.; Zaluzec, N.J.

    1987-08-01

    The development of medium voltage electron microscopes having high brightness electron sources and ultra-high vacuum environments has been anticipated by the microscopy community now for several years. The advantages of such a configuration have been discussed to great lengths, while the potential disadvantages have for the most part been neglected. The most detrimental of these relative to microcharacterization are the effects of electron sputtering and atomic displacement to the local specimen composition. These effects have in the past been considered mainly in the high voltage electron microscope regime and generally were ignored in lower voltage instruments. Recent experimental measurements have shown that the effects of electron sputtering as well as radiation induced segregation can be observed in conventional transmission electron microscopes. It is, therefore, important to determine at what point the effects will begin to manifest themselves in the new generation of medium voltage analytical electron microscopes. In this manuscript we present new calculations which allow the individual experimentalist to determine the potential threshold levels for a particular elemental system and thus avoid the dangers of introducing artifacts during microanalysis. 12 refs., 3 figs

  18. Single electron capture differential cross section in H+ + He collisions at intermediate and high collision energies

    International Nuclear Information System (INIS)

    Abufager, P N; Fainstein, P D; MartInez, A E; Rivarola, R D

    2005-01-01

    The generalized continuum distorted wave-eikonal initial state (CDW-EIS II) approximation is employed to study differential cross sections (DCS) for single electron capture in H + + He collisions at intermediate and high energies. Present results are compared with theoretical calculations obtained using the previous CDW-EIS formulation in order to show the importance of the description of the bound and continuum target states in the entrance and exit channels, respectively. Both DCS are also shown together with other theoretical results and with experimental data

  19. Electron scattering on N2O-from cross sections to diffusion coefficients

    International Nuclear Information System (INIS)

    Mechlinska-Drewko, J.; Wroblewski, T.; Petrovic, Z.L.; Novakovic, V.; Karwasz, G.P.

    2003-01-01

    Results of measurements of the ratio of transverse (D T /μ) and longitudinal (D L /μ) diffusion coefficients to mobility and drift velocity (W) as function of reduced electrical field (E/N) for electrons in nitrous oxide are presented. The coefficients D T /μ and D L /μ have been determined by applying the Townsend-Huxley method. The drift velocities were obtained by using the Bradbury-Nielsen technique. Also the deduced set of total and partial cross sections has been used to calculate the D T /μ and W

  20. Kuang's Semi-Classical Formalism for Calculating Electron Capture Cross Sections: A Space- Physics Application

    Science.gov (United States)

    Barghouty, A. F.

    2014-01-01

    Accurate estimates of electroncapture cross sections at energies relevant to the modeling of the transport, acceleration, and interaction of energetic neutral atoms (ENA) in space (approximately few MeV per nucleon) and especially for multi-electron ions must rely on detailed, but computationally expensive, quantum-mechanical description of the collision process. Kuang's semi-classical approach is an elegant and efficient way to arrive at these estimates. Motivated by ENA modeling efforts for apace applications, we shall briefly present this approach along with sample applications and report on current progress.

  1. Transport coefficients for electrons in argon in crossed electric and magnetic rf fields

    International Nuclear Information System (INIS)

    Raspopovic, Z M; Dujko, S; Makabe, T; Petrovic, Z Lj

    2005-01-01

    Monte Carlo simulations of electron transport have been performed in crossed electric and magnetic rf fields in argon. It was found that a magnetic field strongly affects electron transport, producing complex behaviour of the transport coefficients that cannot be predicted on the basis of dc field theory. In particular, it is important that a magnetic field, if it has sufficiently high amplitude, allows energy gain from the electric field only over a brief period of time, which leads to a pulse of directed motion and consequently to cyclotron oscillations being imprinted on the transport coefficients. Furthermore, this may lead to negative diffusion. The behaviour of drift velocities is also interesting, with a linear (sawtooth) dependence for the perpendicular drift velocity and bursts of drift for the longitudinal. Non-conservative effects are, on the other hand, reduced by the increasing magnetic field

  2. Electron capture to the continuum manifestation in fully differential cross sections for ion impact single ionization

    Science.gov (United States)

    Ciappina, M. F.; Fojón, O. A.; Rivarola, R. D.

    2018-04-01

    We present theoretical calculations of single ionization of He atoms by protons and multiply charged ions. The kinematical conditions are deliberately chosen in such a way that the ejected electron velocity matches the projectile impact velocity. The computed fully differential cross sections (FDCS) in the scattering plane using the continuum-distorted wave-eikonal initial state show a distinct peaked structure for a polar electron emission angle θ k = 0°. This element is absent when a first order theory is employed. Consequently, we can argue that this peak is a clear manifestation of a three-body effect, not observed before in FDCS. We discuss a possible interpretation of this new feature.

  3. Dissociative Excitation of Acetylene Induced by Electron Impact: Excitation-emission Cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    Országh, Juraj; Danko, Marián; Čechvala, Peter; Matejčík, Štefan, E-mail: matejcik@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynská dolina F-2, 842 48 Bratislava (Slovakia)

    2017-05-20

    The optical emission spectrum of acetylene excited by monoenergetic electrons was studied in the range of 190–660 nm. The dissociative excitation and dissociative ionization associated with excitation of the ions initiated by electron impact were dominant processes contributing to the spectrum. The spectrum was dominated by the atomic lines (hydrogen Balmer series, carbon) and molecular bands (CH(A–X), CH(B–X), CH{sup +}(B–A), and C{sub 2}). Besides the discrete transitions, we have detected the continuum emission radiation of ethynyl radical C{sub 2}H(A–X). For most important lines and bands of the spectrum we have measured absolute excitation-emission cross sections and determined the energy thresholds of the particular dissociative channels.

  4. Nuclear Data for Reactor Physics: Cross sections and level densities in the actinide region

    Directory of Open Access Journals (Sweden)

    Bernstein L.

    2010-03-01

    Full Text Available Nuclear data in the actinide region are particularly important because they are basis behind all simulations of nuclear reactor core behaviour over both long time scales (fuel depletion and waste production and short time scales (accident scenarios. Nuclear reaction cross sections must be known as precisely as possible so that core reaction rates can be accurately calculated. Although cross section measurements in this region have been widely performed, for certain nuclei, particularly those with short half lives, direct measurements are either very difficult or impossible and thus reactor simulations must rely on theoretical calculations or extrapolations from neighbouring nuclei. The greatest uncertainty in theoretical cross section calculations comes from the lack of knowledge of level densities, for which predicted values can often be incorrect by a factor of two or more. Therefore there is a strong case for a systematic experimental study of level densities in the actinide region for the purpose of a providing a stringent test of theoretical cross section calculations for nuclei where experimental cross section data are available and b for providing better estimations of cross sections for nuclei in which no cross section data are available.

  5. Programmable Logic Controllers for Systems of Automatic of the Level Crossing

    Directory of Open Access Journals (Sweden)

    Mieczyslaw Kornaszewski

    2006-01-01

    Full Text Available The railway crossings are vulnerable to incidence of high number of accidents often deadly. In order to face this problem, the modern systems of automatic of the level crossing have been introduced. These systems are based on Programmable Logic Controllers, which allow the designers to exploit self-control mechanisms, events acquiring, technical diagnostic which in turn enable remote control and acquisition of faults.

  6. Total and single differential cross sections for the electron impact ionization of the ground state of helium

    International Nuclear Information System (INIS)

    Singh, T.S.C.; Choudhury, K.B.; Singh, M.B.; Deb, N.C.; Mukherjee, S.C.; Mazumdar, P.S.

    1997-01-01

    Total cross sections (TCS) and single differential cross sections (SDCS) have been computed for the single ionization of the ground state of helium by electron impact in a distorted wave formalism which takes into account the effects of the initial and final channel distortions. The present TCS and SDCS results are in fair agreement with the measured values and other theoretical predictions for the incident electron energy E i > 150 eV. (orig.)

  7. Photodouble ionization differential cross sections for D2 with various electron energy sharing conditions

    International Nuclear Information System (INIS)

    Seccombe, D.P.; Collins, S.A.; Reddish, T.J.; Selles, P.; Malegat, L.; Huetz, A.; Kazansky, A.K.

    2002-01-01

    The mutual angular distributions of the two ejected electrons following direct photodouble ionization have been measured for D 2 at an excess energy (E) of 25 eV using linearly polarized light. These (γ, 2e) 'triple' differential cross sections (TDCSs) were obtained for asymmetric electron energy conditions with energy sharing ratios (R=E 2 /E 1 ) of R=24, 11.5, 4 and 2.57. In all cases the 'reference' electron (energy = E 1 ) was oriented along the direction of the electric field vector (ε) and detected in coincidence with a second electron (energy = E 2 ) coplanar with ε and the photon beam direction (kγ). For comparison, helium TDCSs were obtained for the same E and R values under nearly identical spectrometer conditions. These show very good agreement with the results of hyperspherical-R-matrix with semi-classical outgoing waves calculations, thus providing even more confidence in the D 2 TDCSs where there is as yet no accurate ab initio theory. The similarities and differences between the experimental results associated with the two targets are qualitatively discussed in terms of Feagin's model (Feagin J M 1998 J. Phys. B: At. Mol. Opt. Phys. 31 L729). (author)

  8. Treatment of Electronic Energy Level Transition and Ionization Following the Particle-Based Chemistry Model

    Science.gov (United States)

    Liechty, Derek S.; Lewis, Mark

    2010-01-01

    A new method of treating electronic energy level transitions as well as linking ionization to electronic energy levels is proposed following the particle-based chemistry model of Bird. Although the use of electronic energy levels and ionization reactions in DSMC are not new ideas, the current method of selecting what level to transition to, how to reproduce transition rates, and the linking of the electronic energy levels to ionization are, to the author s knowledge, novel concepts. The resulting equilibrium temperatures are shown to remain constant, and the electronic energy level distributions are shown to reproduce the Boltzmann distribution. The electronic energy level transition rates and ionization rates due to electron impacts are shown to reproduce theoretical and measured rates. The rates due to heavy particle impacts, while not as favorable as the electron impact rates, compare favorably to values from the literature. Thus, these new extensions to the particle-based chemistry model of Bird provide an accurate method for predicting electronic energy level transition and ionization rates in gases.

  9. New techniques for multi-level cross section calculation and fitting

    International Nuclear Information System (INIS)

    Froehner, F.H.

    1980-09-01

    A number of recent developments in multi-level cross section work are described. A new iteration scheme for the conversion of Reich-Moore resonance parameters to Kapur-Peierls parameters allows application of Turing's method for Gaussian broadening of meromorphic functions directly to multi-level cross section expressions, without recourse to the Voigt profiles psi and chi. This makes calculation of Doppler-broadened Reich-Moore and MLBW cross sections practically as fast as SLBW and Adler-Adler cross section calculations involving the Voigt profiles. A convenient distant-level treatment utilizing average resonance parameters is presented. Apart from effectively dealing with edge effects in resonance fitting work it also leads to a simple prescription for the determination of bound levels which reproduce the thermal cross sections correctly. A brief discussion of improved resonance shape fitting techniques is included, with empahsis on the importance of correlated errors and proper use of prior information by application of Bayes' theorem. (orig.) [de

  10. Validation of hindi translation of DSM-5 level 1 cross-cutting symptom measure.

    Science.gov (United States)

    Goel, Ankit; Kataria, Dinesh

    2018-04-01

    The DSM-5 Level 1 Cross-Cutting Symptom Measure is a self- or informant-rated measure that assesses mental health domains which are important across psychiatric diagnoses. The absence of this self- or informant-administered instrument in Hindi, which is a major language in India, is an important limitation in using this scale. To translate the English version of the DSM-5 Level 1 Cross-Cutting Symptom Measure to Hindi and evaluate its psychometric properties. The study was conducted at a tertiary care hospital in Delhi. The DSM-5 Level 1 Cross-Cutting Symptom Measure was translated into Hindi using the World Health Organization's translation methodology. Mean and standard deviation were evaluated for continuous variables while for categorical variables frequency and percentages were calculated. The translated version was evaluated for cross-language equivalence, test-retest reliability, internal consistency, and split half reliability. Hindi version was found to have good cross-language equivalence and test-retest reliability at the level of items and domains. Twenty two of the 23 items and all the 23 items had a significant correlation (ρ Cutting Symptom Measure as translated in this study is a valid instrument. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Adriatic storm surges and related cross-basin sea-level slope

    Science.gov (United States)

    Međugorac, Iva; Orlić, Mirko; Janeković, Ivica; Pasarić, Zoran; Pasarić, Miroslava

    2018-05-01

    Storm surges pose a severe threat to the northernmost cities of the Adriatic coast, with Venice being most prone to flooding. It has been noted that some flooding episodes cause significantly different effects along the eastern and western Adriatic coasts, with indications that the difference is related to cross-basin sea-level slope. The present study aims to determine specific atmospheric conditions under which the slope develops and to explore connection with increased sea level along the two coastlines. The analysis is based on sea-level time series recorded at Venice and Bakar over the 1984-2014 interval, from which 38 most intensive storm-surge episodes were selected, and their meteorological backgrounds (ERA-Interim) were studied. The obtained sea-level extremes were grouped into three categories according to their cross-basin sea-level slope: storm surges that slope strongly westward (W type), those that slope eastward (E type) and ordinary storm surges (O type). Results show that the slope is controlled by wind action only, specifically, by the wind component towards a particular coast and by the cross-basin shear of along-basin wind. Meteorological fields were used to force an oceanographic numerical model in order to confirm the empirically established connection between the atmospheric forcing and the slope. Finally, it has been found that the intensity of storm surges along a particular Adriatic coast is determined by an interplay of sea-level slopes in the along and cross-basin directions.

  12. Charging and the cross-field discharge during electron accelerator operation on a rocket

    International Nuclear Information System (INIS)

    Kellogg, P.J.; Monson, S.J.

    1988-01-01

    We present some limited results obtained from the flight of SCEX II, from Poker Flat, Alaska, on January 31, 1987. Some of the experiments were aimed at understanding neutralization processes around an electron beam emitting rocket. It was expected that electrons drifting in the strong electric fields around the charged rocket would acquire sufficient energy to ionize neutrals, and that the resulting ions would be hurled outward at energies up to the rocket potential. Three hemispherical retarding potential analyzers were ejected from the main payload to measure these ions. This experiment was successful, in spite of arcs which developed around the batteries for the electron guns, which degraded the emitted electron beam to unusable levels except for about 8 sec of the flight. Ions were observed at energies up to 175 eV, the limit of the analyzers. The main payload carried, in addition to the electron accelerator, two arms with conducting elements to act as Langmuir probes, and to measure floating potentials. These measurements show that fields sufficient to accelerate electrons to ionizing energies were present around the rocket. (author)

  13. Survey of experimental and theoretical electron-impact ionization cross sections for transition metal ions in low stages of ionization

    International Nuclear Information System (INIS)

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

    1985-03-01

    Electron-ion crossed beams measurements and distorted-wave theory have been employed to make a study of electron-impact ionization for transition metal ions in low stages of ionization. The atomic ions Ti+, Ti 2 +, Ti 3 +, Fe+, Fe 2 +, Fe 3 +, Fe 4 +, Ni+, Ni 2 +, Ni 3 +, Cu+, Cu 2 +, and Cu 3 + are examined

  14. Analysis of Traffic Safety Factors at Level Rail-Road Crossings

    Directory of Open Access Journals (Sweden)

    Tomislav Mlinarić

    2012-10-01

    Full Text Available The paper analyses the main factors of traffic safety andreliabilityat level crossings. The number and causes of accidentsare stated, that result from ignorance, insufficient training ofthe traffic participants, their ilnsponsibility and insufficient orincomplete legislation, as well as from insufficiently professionaland scientifically not serious enough approach to solvingthis cardinal problem in road and railway traffic. Based on theanalysis the causes are determined and solutions proposed, aswell as more efficient methods to improve safety and reduce thenumber of traffic accidents at level crossings.

  15. Cross Sections for Electron-Impact Dissociation of Alternative Etching Gas, C3HF7O

    Science.gov (United States)

    Tanaka, Hideyuki; Toyoda, Hirotaka; Sugai, Hideo

    1998-09-01

    The search for alternative for perfluorocarbon gases from the environmental point of view has resulted in a new etching gas, C3HF7O (1,2,2,2-tetrafluoroethyl-trifluoromethyl ether, abbreviated as HFE-227). In this paper, the first measurement of the absolute cross sections for the dissociation of HFE-227, is reported.The neutral dissociation is measured from the threshold to 250 eV by appearance mass spectrometry in a dual electron beam device.The threshold energies for the neutral dissociation into CF, CF2 and CF3 are 14.7, 12.5 and 11.2 eV, respectively.The cross sections for the dissociation from HFE-227 into CF3 and CF are larger than those from c-C4F8 (octafluorocyclobutane), but not for the dissociation into CF2.Besides the neutral dissociation, the cross sections for the dissociative ionization of HFE-227 are extensively measured for the formation of twelve ionic species, i.e., CO+, CHO+, CF+, CHF+, CFO+, CF2+, CHF2+, CF3+, CHF3+, C2HF2O+, C2HF4+ and C2HF4O+.

  16. Radiation cross-linked plastics: a versatile material solution for packaging, automotive, Electrotechnic and Electronics

    International Nuclear Information System (INIS)

    Rouif, Sophie

    2004-01-01

    Used since the beginning of the 1970s for the production of halogen-free and heat-resistant cables and wires, for conditioning polyethylene hot-water pipes or for the manufacture of heat shrinkable tubes and of tyres, radiation cross-linking is developing fastly today on the scale of plastic-moulded parts, and not only by the mean of EB, but also under gamma rays. Indeed, it improves considerably the performances of a great number of plastics among thermoplastics, elastomers and thermoplastic elastomers (TPE). Radiation cross-linking reinforces the dimensional stability of polymers in chemically aggressive and high-temperature conditions. Radiation cross-linked-based engineering plastics offers OEM and end users in many branches of industry both technical and economical advantages in comparison with high-performances plastics. They constitute a technical and economical compromise between engineering plastics that failed and high-performances plastic, often over-tailored and expensive. This modern industrial technology gives way to new applications and perspectives in various sectors (packaging, automotive, electrotechnic and electronics, including connectors, surface-mounted devices, integrated circuits, 3D-MID, etc.) that are described in the paper

  17. Wood Sawdust/Natural Rubber Ecocomposites Cross-Linked by Electron Beam Irradiation

    Directory of Open Access Journals (Sweden)

    Elena Manaila

    2016-06-01

    Full Text Available The obtaining and characterization of some polymeric eco-composites based on wood sawdust and natural rubber is presented. The natural rubber was cross-linked using the electron beam irradiation. The irradiation doses were of 75, 150, 300 and 600 kGy and the concentrations of wood sawdust were of 10 and 20 phr, respectively. As a result of wood sawdust adding, the physical and mechanical properties such as hardness, modulus at 100% elongation and tensile strength, showed significant improvements. The presence of wood sawdust fibers has a reinforcing effect on natural rubber, similar or better than of mineral fillers. An increase in the irradiation dose leads to the increasing of cross-link density, which is reflected in the improvement of hardness, modulus at 100% elongation and tensile strength of blends. The cross-linking rates, appreciated using the Flory-Rehner equation, have increased with the amount of wood sawdust in blends and with the irradiation dose. Even if the gel fraction values have varied irregularly with the amount of wood sawdust and irradiation dose it was over 90% for all blends, except for the samples without wood sawdust irradiated with 75 kGy. The water uptake increased with increasing of fiber content and decreased with the irradiation dose.

  18. Total cross sections for electron scattering by CO2 molecules in the energy range 400 endash 5000 eV

    International Nuclear Information System (INIS)

    Garcia, G.; Manero, F.

    1996-01-01

    Total cross sections for electron scattering by CO 2 molecules in the energy range 400 endash 5000 eV have been measured with experimental errors of ∼3%. The present results have been compared with available experimental and theoretical data. The dependence of the total cross sections on electron energy shows an asymptotic behavior with increasing energies, in agreement with the Born-Bethe approximation. In addition, an analytical formula is provided to extrapolate total cross sections to higher energies. copyright 1996 The American Physical Society

  19. Patterns of electronic cigarette use and level of psychological distress.

    Directory of Open Access Journals (Sweden)

    Su Hyun Park

    Full Text Available Psychological distress has been correlated with higher levels of nicotine dependence. To date, the possible association between individuals' levels of psychological distress and e-cigarette use has not been investigated, despite the dramatic growth of e-cigarette use in the US. We examined this possible association using a nationally representative sample of US adults.A total of 36,697 adults from the 2014 National Health Interview Survey (NHIS were included. The Kessler 6 scale was used to measure psychological distress. Multivariate logistic regression analysis was conducted to assess the association between level of psychological distress and e-cigarette use.Both e-cigarette and cigarette use varied according to level of psychological distress as well as multiple socio-demographic characteristics. In a multivariate model, psychological distress was significantly associated with the following groups: (a exclusive e-cigarette ever-use (aOR = 3.7; 95% CI = 1.6, 8.6, (b current dual use of e-cigarettes and cigarettes (aOR = 4.6; 95% CI = 3.1, 6.7, (c former cigarette use and ever use of e-cigarette (aOR = 3.2; 95% CI = 2.2, 4.8 and (d current use of cigarettes only (aOR = 2.1; 95% CI = 1.7, 2.6.These are the first data to demonstrate that, as is true for cigarettes, e-cigarette use is associated with increased levels of psychological distress. Further large-scale, longitudinal studies are needed to determine the direction of this relationship and to evaluate the long-term positive and negative consequences of such use.

  20. ZZ ELAST2, Database of Cross Sections for the Elastic Scattering of Electrons and Positrons by Atoms

    International Nuclear Information System (INIS)

    2002-01-01

    1 - Historical background and information: This database is an extension of the earlier database, 'Elastic Scattering of Electrons and Positrons by Atoms: Database ELAST', Report NISTIR 5188, 1993. Cross sections for the elastic scattering of electrons and positrons by atoms were calculated at energies from 1 KeV to 100 MeV. Up to 10 MeV the RELEL code of Riley was used. Above 10 MeV the ELSCAT code was used, which calculated the factored cross sections and evaluates the screening factor Kscr in WKB approximation. 2 - Application of the data: This database was developed to provide input for the transport codes, such as ETRAN, and includes differential cross sections, the total cross section, and the transport cross sections. In addition, a code TRANSX is provided that generates transport cross section of arbitrary order needed as input for the calculation of Goudsmit-Saunderson multiple-scattering angular distribution 3 - Source and scope of data: The database includes cross sections at 61 energies for electrons and 41 energies from positrons, covering the energy region from 1 KeV to 100 MeV. The number of deflection angles included in the database is 314 angles. Total and transport cross sections are also included in this package. The data files have an extension (jjj) that represents the atomic number of the target atom. The database includes auxiliary data files that enable the ELASTIC code to include the following optional modifications: (i) the inclusion of the exchange correction for electrons scattering; (ii) the conversion of the cross sections for scattering by free atoms to cross sections for scattering by atoms in solids; (iii) ti reduction of the cross sections at large angles and at high energies when the nucleus is treated as an extended rather than a point charge

  1. Photovoltaic Shading Testbed for Module-Level Power Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Deline, C.; Meydbray, J.; Donovan, M.; Forrest, J.

    2012-05-01

    This document describes a repeatable test procedure that attempts to simulate shading situations, as would be experienced by typical residential rooftop photovoltaic (PV) systems. This type of shading test is particularly useful to evaluate the impact of different power conversion setups, including microinverters, DC power optimizers and string inverters, on overall system performance. The performance results are weighted based on annual estimates of shade to predict annual performance improvement. A trial run of the test procedure was conducted with a side by side comparison of a string inverter with a microinverter, both operating on identical 8kW solar arrays. Considering three different shade weighting conditions, the microinverter was found to increase production by 3.7% under light shading, 7.8% under moderate shading, and 12.3% under heavy shading, relative to the reference string inverter case. Detail is provided in this document to allow duplication of the test method at different test installations and for different power electronics devices.

  2. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Makoto [Gaseous Electronics Institute, Nagoya, Aichi (Japan)

    2003-04-01

    A bibliography of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for carbon dioxide (CO{sub 2}). About 1,240 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1901 through 2000 for CO{sub 2}. Finally, author's comments for CO{sub 2} electron collision cross sections are given. (author)

  3. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Argon

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Makoto [Gaseous Electronics Institute, Nagoya, Aichi (Japan)

    2003-01-01

    A bibliography of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for argon (Ar). About 1,960 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1921 through 2000 for Ar. Finally, author's recommended Ar electron collision cross section set is given in numerical tables. (author)

  4. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Sulphur hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Makoto [Gaseous Electronics Institute, Nagoya, Aichi (Japan)

    2003-05-01

    A bibliography of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for sulphur hexafluoride (SF{sub 6}). About 920 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1934 through 2000 for SF{sub 6}. Finally, author's comments for SF{sub 6} electron collision cross section are given. (author)

  5. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Carbon dioxide

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2003-04-01

    A bibliography of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for carbon dioxide (CO 2 ). About 1,240 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1901 through 2000 for CO 2 . Finally, author's comments for CO 2 electron collision cross sections are given. (author)

  6. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Halogen molecules

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2003-12-01

    A bibliographies of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for halogen molecules (F 2 , Cl 2 , Br 2 , I 2 ). About 190(F 2 ), 360(Cl 2 ), 140(Br 2 ) and 240(I 2 ) papers were compiled respectively. A comprehensive author indexes for each molecule are included. The bibliography covers the period 1901 through 2000 for F 2 -I 2 . Finally, author's comments for F 2 -I 2 electron collision cross sections are given. (author)

  7. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Hydrogen halide molecules

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2004-03-01

    Bibliographies of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for hydrogen halide molecules (HF, HCL, HBr, HI). About 330 (HF), 420 (HCl) 220 (HBr) and 150 (HI) papers were compiled respectively. Comprehensive author indexes for each molecule are included. The bibliography covers the period 1903 through 2000 for HF-HI. Finally, author's comments for HBr electron collision cross sections are given. (author)

  8. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Water vapour

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2003-12-01

    Bibliographies of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for water vapour (H 2 O, D 2 O and HDO). About 1200 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1915 through 2000 for H 2 O. Finally, author's comments for electron collision cross sections and photodissociation processes of H 2 O are given. (author)

  9. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Hydrogen molecules

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2004-02-01

    Bibliographies of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for hydrogen molecules (H 2 , HD, HT, D 2 , DT, T 2 ). About 2200 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1901 through 2000 for H 2 . Finally, author's comments for H 2 electron collision cross sections are given. (author)

  10. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Nitrogen molecule

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2003-06-01

    A bibliography of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for nitrogen molecule (N 2 ). About 2240 papers were compiled. A comprehensive author index is include. The bibliography covers the period 1906 through 2000 for N 2 . Finally, author's comments for N 2 electron collision cross section are given. (author)

  11. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Argon

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2003-01-01

    A bibliography of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for argon (Ar). About 1,960 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1921 through 2000 for Ar. Finally, author's recommended Ar electron collision cross section set is given in numerical tables. (author)

  12. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Sulphur hexafluoride

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2003-05-01

    A bibliography of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for sulphur hexafluoride (SF 6 ). About 920 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1934 through 2000 for SF 6 . Finally, author's comments for SF 6 electron collision cross section are given. (author)

  13. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Ammonia and phosphine

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2004-08-01

    Bibliographies of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for ammonia (NH 3 ) and phosphine (PH 3 ). About 820 (NH 3 ) and 190 (PH 3 ) papers were compiled respectively. Comprehensive author indexes for each molecule are included. The bibliography covers the period 1922 through 2000 for NH 3 and 1928 through 2000 for PH 3 . Finally, author's comments for NH 3 electron collision cross sections are given. (author)

  14. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Makoto [Gaseous Electronics Institute, Nagoya, Aichi (Japan)

    2003-04-01

    A bibliography of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for carbon dioxide (CO{sub 2}). About 1,240 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1901 through 2000 for CO{sub 2}. Finally, author's comments for CO{sub 2} electron collision cross sections are given. (author)

  15. Measurement of differential incoherent scattering cross-sections of 145 keV photons from K-shell electrons

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, V B; Ghumman, B S [Punjabi Univ., Patiala (India). Dept. of Physics

    1980-06-01

    Differential cross-sections for incoherent scattering of 145 keV photons from K-shell electrons of tin, silver and molybdenum have been measured at 110deg to investigate the effect of electron binding on differential cross-sections in the low energy region. The incoherent scattered photons are selected in coincidence with X-rays which follow the vacancies caused by the ejection of the electrons. NaI(Tl) scintillators are used for the detection of scattered photons and emitted X-rays. The experimental results are compared with the available theoretical data.

  16. Cross-sections for dissociative excitation of lead atom in collisions of slow electrons with PbI2 molecules

    International Nuclear Information System (INIS)

    Smirnov, Yu.M.

    2006-01-01

    The dissociative excitation of the lead atom in e-PbI 2 collisions has been studied experimentally. 27 excitation cross-sections are measured at an exciting-electron energy of 100 eV. Nine optical excitation functions are recorded at the electron energy varying in the 0-100 eV range. The most possible reaction channels at low electron energies along with the relation of the dissociative-excitation cross-sections of the lead atom both in e-PbI 2 and e-PbCl 2 collisions are discussed. (authors)

  17. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Xenon

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2003-09-01

    A bibliographies of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for xenon (Xe). About 1180 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1921 through 2000 for Xe. Finally, author's recommended Xe electron collision cross section set is given by number tables. (author)

  18. Bibliography of electron and photon cross sections with atoms and molecules. Published in the 20th century. Methane

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Makoto [Gaseous Electronics Inst., Sakae, Nagoya (Japan)

    2004-10-01

    Bibliographies of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for methane (CH{sub 4}). About 1050 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1924 through 2000 for CH{sub 4}. Finally, author's comments for CH{sub 4} electron collision cross sections are given. (author)

  19. Energetic Electron Acceleration Observed by MMS in the Vicinity of an X-Line Crossing

    Science.gov (United States)

    Jaynes, A. N.; Turner, D. L.; Wilder, F. D.; Osmane, A.; Baker, D. N.; Blake, J. B.; Fennell, J. F.; Cohen, I. J.; Mauk, B. H.; Reeves, G. D.; hide

    2016-01-01

    During the first months of observations, the Magnetospheric Multiscale Fly's Eye Energetic Particle Spectrometer instrument has observed several instances of electron acceleration up to greater than 100 keV while in the vicinity of the dayside reconnection region. While particle acceleration associated with magnetic reconnection has been seen to occur up to these energies in the tail region, it had not yet been reported at the magnetopause. This study reports on observations of electron acceleration up to hundreds of keV that were recorded on 19 September 2015 around 1000 UT, in the midst of an X-line crossing. In the region surrounding the X-line, whistler-mode and broadband electrostatic waves were observed simultaneously with the appearance of highly energetic electrons which exhibited significant energization in the perpendicular direction. The mechanisms by which particles may be accelerated via reconnection-related processes are intrinsic to understanding particle dynamics among a wide range of spatial scales and plasma environments.

  20. Critically assessed electron-impact excitation cross sections for He(11S)

    International Nuclear Information System (INIS)

    Heer, F.J. de

    1998-11-01

    In this paper we reconsider the previous assessment of collision strengths, now mostly presented as cross sections, for excitation of He(1 1 S) to He(n 1,3 L) states (n=2-4, L=0-3). Due to the appearance of additional theoretical results the assessment can now be often given within smaller error limits than before for the singlet levels, as well as for the lower triplet levels (n=2). For the higher excited triplet states more studies are desirable to reduce the possible errors. (author)

  1. Absolute experimental cross sections for the ionization of singly charged barium ions by electron impact: Technical summary report

    International Nuclear Information System (INIS)

    Feeney, R.K.; Hooper, J.W.

    1971-01-01

    The absolute cross sections for the single ionization of Ba + ions by electron impact have been measured as a function of incident electron energy over the electron energy range from below threshold (10.001 eV) to approximately 1000 eV. It is found that the cross section increases from 1.94 x 10 -16 cm 2 to 3.76 x 10 -16 cm 2 between 15.5 and 18 eV actual incident electron energy. This rapid rise is interpreted as the onset of autoionization. Some evidence of structure occurring near the peak of the cross section curve such as found in the isoelectronic system of Cs is observed, but the relative magnitude of the apparent structure is of the same order as the 90% random error confidence limits and thus cannot conclusively be regarded as being present. 56 refs., 16 figs., 7 tabs

  2. A Survey of Electron Impact Cross-Sections for Halogens and Halogen Compounds of Interest to Plasma Processing

    Science.gov (United States)

    Sharma, S. P.; Rao, M. V. V. S.; Arnold, James O. (Technical Monitor)

    1998-01-01

    Published electron impact cross section data on halogens Cl2, F2, and halogen containing compounds such as Cx Fy, HCl, Cx Cly Fz are reviewed and critically evaluated based on the information provided by various researchers. The present work reports data on electron impact excitation, ionization, dissociation, electron attachment, electron detachment, and photo detachment. Elastic scattering cross sections and data on bulk properties such as diffusion coefficients in various background gases are also evaluated. Since some of the cross sectional data is derived from indirect measurements such as drift velocity, care has been taken to reconcile the differences among the reported data with due attention to the measurement technique. In conclusion, the processes with no or very limited amount of data and questionable set of data are identified and recommendation for further research direction is made.

  3. Proton NMR for Measuring Quantum Level Crossing in the Magnetic Molecular Ring Fe10

    International Nuclear Information System (INIS)

    Julien, M.; Jang, Z.H.; Borsa, F.; Julien, M.; Lascialfari, A.; Borsa, F.; Horvatic, M.; Caneschi, A.; Gatteschi, D.

    1999-01-01

    The proton nuclear spin-lattice relaxation rate 1/T 1 has been measured as a function of temperature and magnetic field (up to 15thinspthinspT) in the molecular magnetic ring Fe 10 ( OCH 3 ) 20 (O 2 CCH 2 Cl) 10 (Fe10). Striking enhancement of 1/T 1 is observed around magnetic field values corresponding to a crossing between the ground state and the excited states of the molecule. We propose that this is due to a cross-relaxation effect between the nuclear Zeeman reservoir and the reservoir of the Zeeman levels of the molecule. This effect provides a powerful tool to investigate quantum dynamical phenomena at level crossing. copyright 1999 The American Physical Society

  4. Measurement of charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-12-01

    Measurements of the cross sections for charged current deep inelastic scattering in e - p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb -1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections dσ/dQ 2 , dσ/dx and dσ/dy are presented for Q 2 >200 GeV 2 . The double-differential cross-section d 2 σ/dxdQ 2 is presented in the kinematic range 280 2 and 0.015< x<0.65. The measured cross sections are compared with the predictions of the Standard Model. (orig.)

  5. Levels of saliva cotinine in electronic cigarette users.

    Science.gov (United States)

    Etter, Jean-François

    2014-05-01

    To assess saliva cotinine levels in experienced users of e-cigarettes ('vapers'). An internet survey in 2011 and 2012, with collection of saliva vials by mail. Participants were 71 users of e-cigarettes enrolled mainly on websites and online forums dedicated to e-cigarettes. Use of e-cigarettes, tobacco and nicotine medications. Collection of saliva by mail and analysis of cotinine by liquid chromatography-mass spectrometry. Most participants (89%) were former smokers, most (92%) were using e-cigarettes daily, had been using e-cigarettes for 12 months on average and puffed a median of 150 times per day on their e-cigarettes [mean = 220 puffs/day, 95% confidence interval (CI) = 169-271]. The median concentration of nicotine in refill liquids was 16 mg/ml (mean = 16.4, 95% CI = 14.5-18.3). In the 62 e-cigarette users who, in the past 5 days, had not used any tobacco or nicotine medications, the median cotinine level was 353 ng/ml (mean = 374, 95% CI = 318-429), the correlation between cotinine and nicotine concentration in e-liquids was r = 0.33 (P = 0.013), and the correlation between cotinine and the number of cigarettes smoked per day before quitting smoking was r = 0.48 (P Addiction.

  6. Cross-Circulating Current Suppression Method for Parallel Three-Phase Two-Level Inverters

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Guo, Xiaoqiang

    2015-01-01

    The parallel architecture is very popular for power inverters to increase the power level. This paper presents a method for the parallel operation of inverters in an ac-distributed system, to suppress the cross-circulating current based on virtual impedance without current-sharing bus...

  7. Polymers and Cross-Linking: A CORE Experiment to Help Students Think on the Submicroscopic Level

    Science.gov (United States)

    Bruce, Mitchell R. M.; Bruce, Alice E.; Avargil, Shirly; Amar, Francois G.; Wemyss, Thomas M.; Flood, Virginia J.

    2016-01-01

    The Polymers and Cross-Linking experiment is presented via a new three phase learning cycle: CORE (Chemical Observations, Representations, Experimentation), which is designed to model productive chemical inquiry and to promote a deeper understanding about the chemistry operating at the submicroscopic level. The experiment is built on two familiar…

  8. Compilation of electron collision excitation cross sections for neutral argon; Compilacion de resultados de secciones eficaces de excitacion para niveles del Argon neutro

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, F

    1993-07-01

    The present work presents a compilation and critical analysis of the available data on electron collision excitation cross sections for neutral Argon levels. This study includes: 1.- A detailed description in intermediate coupling for all the levels belonging the 20 configurations 3p5 ns (n=4to 12), np(n=4to8) and nd(n=3to8)of neutral Argon. 2.- Calculation of the electron collision excitation cross sections in Born and Born-Oppenheimer-Ochkur approximations for all the levels in the 14 configurations 3p5 ns (n=4 to 7), np (n=4 to 7) and nd (n=3 to 8). 3.- comparison and discussion of the compiled data. These are the experimental and theoretical values available from the literature, and those from this work. 4.- Analysis of the regularities and systematic behaviors in order to determine which values can be considered more reliable. It is show that the concept of one electron cross section results quite useful for this purpose. In some cases it has been possible to obtain in this way approximate analytical expressions interpolating the experimental data. 5.- All the experimental and theoretical values studied are graphically presented and compared. 6.- The last part of the work includes a listing of several general purpose programs for Atomic Physics calculations developed for this work. (Author) 35 refs.

  9. Level crossings, excess times, and transient plasma–wall interactions in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Theodorsen, A., E-mail: audun.theodorsen@uit.no; Garcia, O. E., E-mail: odd.erik.garcia@uit.no [Department of Physics and Technology, UiT The Arctic University of Norway, N-9037 Tromsø (Norway)

    2016-04-15

    Based on a stochastic model for intermittent fluctuations in the boundary region of magnetically confined plasmas, an expression for the level crossing rate is derived from the joint distribution of the process and its derivative. From this the average time spent by the process above a certain threshold level is obtained. This provides novel predictions of plasma–wall interactions due to transient transport events associated with a radial motion of blob-like structures in the scrape-off layer.

  10. Cross-Level Analysis of Social Media: Toward the Construction of an Ecological Framework

    OpenAIRE

    Jung, Joo-Young; Moro, Munehito; Joo-Young, Jung; Munehito, Moro

    2012-01-01

    The media environment has undergone significant changes with the advent of the Internet. In the recent years, the prevalence and popularity of “social media” is re-shaping the ways in which people communicate and obtain information. This paper proposes a framework that conceptualizes a cross-level functionality of social media. We conceptualize social media as an information system functioning at micro-(interpersonal), meso-(group or organizational), and macro-(mass media) levels. Based on me...

  11. Two-electron excitation to Rydberg levels in fast I6+ on hydrogen collisions

    International Nuclear Information System (INIS)

    Liao, C.; Hagmann, S.; Zouros, T.J.M.; Montenegro, E.C.; Toth, G.; Richard, P.; Grabbe, S.; Bhalla, C.P.

    1995-01-01

    The emission of electrons in the forward direction in collisions of 0.3 MeV/u I 6+ with H 2 has been studied, and strong autoionization peaks are observed on the shoulder of the cusp peak. The energies of these autoionization lines in the projectile rest frame are determined by high-resolution electron spectroscopy. Using the electron projectile final charge state coincidence technique, we probe different collision mechanisms, which create continuum electrons that are slow in the projectile rest frame. We conclude that the observed autoionization lines are due to two electron excitation to projectile Rydberg levels. (orig.)

  12. Eikonal calculation of electron-capture cross sections in collisions of H atoms with fast projectiles

    International Nuclear Information System (INIS)

    Ho, T.S.; Lieber, M.; Chan, F.T.

    1981-01-01

    We have employed the eikonal method to calculate the cross section for the capture of an electron into an arbitrary nl subshell in collisions between hydrogen atoms and fast projectiles. the projectiles were protons, C 6+ , O 8+ , and Fe 24+ . The energy ranges considered were 20--100 keV in the proton case, and 40--200 keV per nucleon in the other cases. These projectiles were selected because of their importance in fusion plasmas. For the highly charged case of Fe 24+ we found that our formulas, while exact, involved a high degree of cancellation and produced unreliable numerical results, so that a numerical integration of the penultimate formula was substituted. In the proton case agreement with recent experimental data is excellent

  13. Multiphoton effects in electron-ion scattering: A limitation of the cross-section treatment

    International Nuclear Information System (INIS)

    Torres Silva, H.; Sakanaka, P.H.; Braga, L.C.

    1991-07-01

    The differential cross-section for inelastic scattering in the presence of an intense laser field, when applied to the calculation of energy balance and heating by multiphoton process, is a problem which is not completely solved yet. One of the main difficulties is the calculation of the absorption coefficients α-bar for a monoenergetic beam of electrons scattered by a static potential. There are contradictory results shown by different authors. Here we have derived α-bar starting under the framework of quantum mechanics and then making the classical correspondence (h/2π → 0) according to the kinetic theory, and show that the absorption coefficient is always positive for all values of the particle incoming velocity, v-vector i . Furthermore, we show that in the calculation of α-bar we recover the Coulomb logarithm term. (author). 18 refs, 5 figs, 2 tabs

  14. ELECTRON TEMPERATURE FLUCTUATIONS AND CROSS-FIELD HEAT TRANSPORT IN THE EDGE OF DIII-D

    International Nuclear Information System (INIS)

    RUDAKOV, DL; BOEDO, JA; MOYER, RA; KRASENINNIKOV, S; MAHDAVI, MA; McKEE, GR; PORTER, GD; STANGEBY, PC; WATKINS, JG; WEST, WP; WHYTE, DG.

    2003-01-01

    OAK-B135 The fluctuating E x B velocity due to electrostatic turbulence is widely accepted as a major contributor to the anomalous cross-field transport of particles and heat in the tokamak edge and scrape-off layer (SOL) plasmas. This has been confirmed by direct measurements of the turbulent E x B transport in a number of experiments. Correlated fluctuations of the plasma radial velocity v r , density n, and temperature T e result in time-average fluxes of particles and heat given by (for electrons): Equation 1--Λ r ES = r > = 1/B varφ θ ; Equation 2--Q r ES = e (tilde v) r > ∼ 3/2 kT e Λ r ES + 3 n e /2 B varφ e (tilde E) θ > Q conv + Q cond . The first term in Equation 2 is referred to as convective and the second term as conductive heat flux. Experimental determination of fluxes given by Equations 1 and 2 requires simultaneous measurements of the density, temperature and poloidal electric field fluctuations with high spatial and temporal resolution. Langmuir probes provide most readily available (if not the only) tool for such measurements. However, fast measurements of electron temperature using probes are non-trivial and are not always performed. Thus, the contribution of the T e fluctuations to the turbulent fluxes is usually neglected. Here they report results of the studies of T e fluctuations and their effect on the cross-field transport in the SOL of DIII-D

  15. Validity of the independent-processes approximation for resonance structures in electron-ion scattering cross sections

    International Nuclear Information System (INIS)

    Badnell, N.R.; Pindzola, M.S.; Griffin, D.C.

    1991-01-01

    The total inelastic cross section for electron-ion scattering may be found in the independent-processes approximation by adding the resonant cross section to the nonresonant background cross section. We study the validity of this approximation for electron excitation of multiply charged ions. The resonant-excitation cross section is calculated independently using distorted waves for various Li-like and Na-like ions using (N+1)-electron atomic-structure methods previously developed for the calculation of dielectronic-recombination cross sections. To check the effects of interference between the two scattering processes, we also carry out detailed close-coupling calculations for the same atomic ions using the R-matrix method. For low ionization stages, interference effects manifest themselves sometimes as strong window features in the close-coupling cross section, which are not present in the independent-processes cross section. For higher ionization stages, however, the resonance features found in the independent-processes approximation are found to be in good agreement with the close-coupling results

  16. Inclusive and exclusive cross sections for multiple ionization by fast, highly charged ions in the independent-electron approximation

    International Nuclear Information System (INIS)

    Ben-Itzhak, I.; Gray, T.J.; Legg, J.C.; McGuire, J.H.

    1988-01-01

    Cross sections for the ionization of n of N electrons with equal single-electron ionization probability P are considered. When both N and the projectile charge q are large, the cross sections for single and double ionization are both found to be approximately linear in q at 1 MeVamu. The ratio of double-to-single-ionization cross sections is independent of q. Moreover, first-order perturbation theory for the single-electron ionization probability P, which varies as q 2 , is found to be applicable due to the damping of contributions with large P caused by factors of (1-P)/sup N/ - /sup n/. For large P there are differences between the inclusive probability P and the probability NP commonly used for a target with N electrons. Both of these probabilities differ significantly from the exclusive probability NP(1-P)/sup N/ -1 for the ionization of only one electron. For large N and large q, the exclusive ionization probabilities for removing exactly n of the N electrons tend to be concentrated in somewhat separate ranges of impact parameters b, defining impact-parameter ''windows.'' The windows which we obtain using the quantum-mechanical semiclassical-Coulomb-approximation (SCA) probabilities are similar to those using classical Monte Carlo calculations. Model calculations, based on analytic fits to the SCA probabilities, are used to obtain approximate analytic expressions for single- and double-ionization cross sections and for the impact-parameter windows

  17. Low-frequency instabilities of electron-hole plasmas in crossed fields

    International Nuclear Information System (INIS)

    Schneider, W.; Kirchesch, P.

    1978-01-01

    Using local point-contact probes, we observed two types of low-frequency instabilities in n-InSb at 85 K if the samples were exposed to crossed fields. One is a local density instability with threshold frequencies of f = 1 ... 20 Mc, the other a more turbulent current instability. The threshold values of U 0 and B for the onset of these instabilities and the dependence of their amplitudes on the fields have been measured. If a rectangular semiconductor slab is placed in crossed fields, regions of high electric field strength at opposite edges of the contacts are caused by the distortion of the Hall field, giving rise to the generation of electron-hole plasmas by impact ionization. These plasmas are the sources of the observed instabilities. This is especially evident in the case of the local density instability, which originates at the anode high field corner. Several possible reasons for the development of the instabilities are discussed. (orig.) [de

  18. A comparison and cross-reference of commercial low-level radioactive waste acceptance criteria

    International Nuclear Information System (INIS)

    Kerr, T.A.

    1997-04-01

    This document, prepared by the National Low-Level Waste Management Program at the Idaho National Engineering and Environmental Laboratory, is a comparison and cross-reference of commercial low-level radioactive waste acceptance criteria. Many of these are draft or preliminary criteria as well as implemented criteria at operating low-level radioactive waste management facilities. Waste acceptance criteria from the following entities are included: US Nuclear Regulatory Commission, South Carolina, Washington, Utah, Nevada, California, illinois, Texas, North Carolina, Nebraska, Pennsylvania, New York, and the Midwest Compact Region. Criteria in the matrix include the following: physical form, chemical form, liquid limits, void space in packages, concentration averaging, types of packaging, chelating agents, solidification media, stability requirements, sorptive media, gas, oil, biological waste, pyrophorics, source material, special nuclear material, package dimensions, incinerator ash, dewatered resin, transuranics, and mixed waste. Each criterion in the matrix is cross-referenced to its source document so that exact requirements can be determined

  19. Electron beam cross-linking of natural rubber/linear-low density polyethylene blends

    International Nuclear Information System (INIS)

    Ahmad, A.; Mohd, D. H.; Abdullah, I.

    2005-01-01

    Effects of electron beam irradiation on the mechanical properties and morphological structure of natural rubber/linear-low density polyethylene blend was investigated The natural rubber/linear-low density polyethylene blend was prepared by melt blending in a Haake internal mixer at 140 d ig C , rotor speed of 50 rpm, and in 15 min Liquid natural rubber was incorporated into the blend as a compatibilizer Samples in the form of 1 mm sheets were exposed to 50-300 kGy of electron beam irradiation and analyzed for swelling index and gel content, tensile strength, and surface morphology. The result Indicated that gel content and mechanical properties of the samples increased with radiation dosage. The honey-comb structure of the surface morphology in low dosage irradiated samples slowly transformed into a continuous matrix on increasing radiation dose The variation of mechanical and physical properties was due to Increase in cross-linking density in the rubber and plastic phases and rubber-plastic Interaction on irradiation

  20. Cross section measurements of the elastic electron - deuteron scattering at MAMI

    Energy Technology Data Exchange (ETDEWEB)

    Kohl, Yvonne [Universitaet Mainz, Institut fuer Kernphysik (Germany); Collaboration: A1-Collaboration

    2015-07-01

    The electromagnetic form factors of light nuclei provide a sensitive test of our understanding of nuclei. Because the deuteron has spin one, three form factors are needed to fully describe the electromagnetic structure of the deuteron. Especially the deuteron charge radius is a favourite observable to compare experiment and calculation. Recently, an extensive measurement campaign has been performed at MAMI (Mainzer Microtron) to determine the deuteron charge radius using elastic electron scattering - with the aim to halve the error compared to previous such experiments. The experiment took place at the 3-spectrometer facility of the A1-collaboration. Cross section measurements of the elastic electron-deuteron scattering have been performed for 180 different kinematic settings in the low momentum transfer region. From these, the charge form factor can precisely be determined. Fitting the form factor with an appropiate fit function, the radius can then be determined from the slope at zero momentum transfer. The determined radius could then be used as a counterweight to the value obtained from the advanced atomic Lamb shift measurements, thus providing additional insight to the proton radius puzzle.

  1. Real-time observation of intersystem crossing induced by charge recombination during bimolecular electron transfer reactions

    KAUST Repository

    Alsam, Amani Abdu

    2016-09-21

    Real-time probing of intersystem crossing (ISC) and triplet-state formation after photoinduced electron transfer (ET) is a particularly challenging task that can be achieved by time-resolved spectroscopy with broadband capability. Here, we examine the mechanism of charge separation (CS), charge recombination (CR) and ISC of bimolecular photoinduced electron transfer (PET) between poly[(9,9-di(3,3′-N,N’-trimethyl-ammonium) propyl fluorenyl-2,7-diyl)-alt-co-(9,9-dioctyl-fluorenyl-2,7-diyl)] diiodide salt (PFN) and dicyanobenzene (DCB) using time-resolved spectroscopy. PET from PFN to DCB is confirmed by monitoring the transient absorption (TA) and infrared spectroscopic signatures for the radical ion pair (DCB─•-PFN+•). In addition, our time-resolved results clearly demonstrate that CS takes place within picoseconds followed by CR within nanoseconds. The ns-TA data exhibit the clear spectroscopic signature of PFN triplet-triplet absorption, induced by the CR of the radical ion pairs (DCB─•-PFN+•). As a result, the triplet state of PFN (3PFN*) forms and subsequently, the ground singlet state is replenished within microseconds. © 2016

  2. Panel Data with Cross-Sectional Dependence Characterized by a Multi-Level Factor Structure

    DEFF Research Database (Denmark)

    Rodríguez-Caballero, Carlos Vladimir

    A panel data model with a multi-level cross-sectional dependence is proposed. The factor structure is driven by top-level common factors as well as non-pervasive factors. I propose a simple method to filter out the full factor structure that overcomes limitations in standard procedures which may...... mix up both levels of unobservable factors and may hamper the identification of the model. The model covers both stationary and non-stationary cases and takes into account other relevant features that make the model well suited to the analysis of many types of time series frequently addressed...

  3. Angular differential studies of electron transfer in collisions of He-like ions with Na(3s) : The role of electron saddle crossings

    NARCIS (Netherlands)

    Blank, I.; Otranto, S.; Meinema, C.; Olson, R. E.; Hoekstra, R.

    2013-01-01

    We present a systematic experimental and theoretical study of angular differential cross sections of single-electron transfer in collisions of N5+, O6+, and Ne8+ with ground-state Na(3s) in the collision energy range from 1 to 8 keV/amu. Experiments were performed using recoil-ion momentum

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-05-15

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

  5. PERCEPTION LEVEL EVALUATION OF RADIO ELECTRONIC MEANS TO A PULSE OF ELECTROMAGNETIC RADIATION

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available The method for evaluating the perception level of electronic means to pulsed electromagnetic radiation is consid- ered in this article. The electromagnetic wave penetration mechanism towards the elements of electronic systems and the impact on them are determined by the intensity of the radiation field on the elements of electronic systems. The impact of electromagnetic radiation pulses to the electronic systems refers to physical and analytical parameters of the relationship between exposure to pulses of electromagnetic radiation and the sample parameters of electronic systems. A physical and mathematical model of evaluating the perception level of electronic means to pulsed electromagnetic radiation is given. The developed model was based on the physics of electronics means failure which represents the description of electro- magnetic, electric and thermal processes that lead to the degradation of the original structure of the apparatus elements. The conditions that lead to the total equation electronic systems functional destruction when exposed to electromagnetic radia- tion pulses are described. The internal characteristics of the component elements that respond to the damaging effects are considered. The ratio for the power failure is determined. A thermal breakdown temperature versus pulse duration of expo- sure at various power levels is obtained. The way of evaluation the reliability of electronic systems when exposed to pulses of electromagnetic radiation as a destructive factor is obtained.

  6. Accurate calculation of the differential cross section of compton scattering with electron mixed chain propagator in SM

    International Nuclear Information System (INIS)

    Chen Xuewen; Fang Zhenyun; Shi Chengye

    2012-01-01

    By using the electroweak standard model (SM), we analyzed the framework of electron mixed chain propagator which composed of serious of different physical loops participating in electroweak interaction and completed the relevant analytical calculation. Then, we obtained the analytical result of electron mixed chain propagator. By applying our result to Compton scattering, the differential cross section of Compton scattering dσ SM (chain) /dcosθ is counted accurately. This result is compared with the lowest order differential cross section dσ (tree) /dcosθ and the electronic chain propagator Compton scattering differential cross section dσ QED (chain) /dcosθ in quantum electrodynamics (QED). It can be seen that dσ SM (chain ) /dcosθ can show the radiation correction more subtly than dσ QED (chain) /dcosθ. (authors)

  7. Employability Competencies for Entry Level Occupations in Electronics. Part One: Basic Theory.

    Science.gov (United States)

    Werner, Claire

    This syllabus, which is the first of a two-volume set describing the basic competencies needed by entry-level workers in the field of electronics, deals with the basic theories of electricity and electronics. Competencies are organized according to the following skills areas: the meaning of electricity, how electricity works, resistors, Ohm's law,…

  8. Effects of shape differences in the level densities of three formalisms on calculated cross-sections

    International Nuclear Information System (INIS)

    Fu, C.Y.; Larson, D.C.

    1998-01-01

    Effects of shape differences in the level densities of three formalisms on calculated cross-sections and particle emission spectra are described. Reactions for incident neutrons up to 20 MeV on 58 Ni are chosen for illustrations. Level density parameters for one of the formalisms are determined from the available neutron resonance data for one residual nuclide in the binary channels and from fitting the measured (n,n'), (n,p) and (n,α) cross-sections for the other two residual nuclides. Level density parameters for the other two formalisms are determined such that they yield the same values as the above one at two selected energies. This procedure forces the level densities from the three formalisms used for the binary pat of the calculation to be as close as possible. The remaining differences are in their energy dependences (shapes). It is shown that these shape differences alone are enough to cause the calculated cross-sections and particle emission spectra to be different by up to 60%. (author)

  9. Evaluation of Railway Level Crossing Attributes on Accident Causation in Lagos, Nigeria.

    Directory of Open Access Journals (Sweden)

    Adeolu O Dina

    2017-01-01

    Full Text Available Abstract The study examines the contribution of Railway Level Crossing (RLCphysical attributes to accident occurrence using the12 major level crossings within the Lagos metropolis. The 48km single track mainline section under consideration which barely make up 1.1% of the entire narrow gauge track network of the country within a 5 year period contributed about 45% of the total National crossing accidents recorded in Nigeria. The method of investigation involved recording the individual attributes of each RLC such asgates, pedestrian traffic, car traffic light, proximity of signage to crossing, vehicular traffic as dummy variables.The regression analysis  was used to measure their effect on accidents.The result indicates gates, pedestrians and the location of signage had significant impact on accidents occurrence at level crossings within Lagos metropolis. Based on the findings, enhancement of active warning systems among other recommendations was suggested as potent counter measures for RLC accident reduction. Abstrak Penelitian menguji tingkat kontribusi atribut fisik dari perlintasan jalan kereta api terhadap kejadian kecelakaan menggunakan 12 perlintasan utama dalam kota metropolis Lagos. 48 km jalan utama tunggal menjadi pertimbangan yang hampir meningkat 1.1% dari seluruh trek sempit jaringan negara dalam jangka waktu 5 tahun menyumbang sekitar 45% dari total kecelakaan perlintasan secara Nasional di Nigeria. Metode penelitian melibatkan catatan dari masing-masing atribut RLC seperti pintu gerbang, pejalan kaki, lampu lalu lintas mobil, kedekatan tanda penyebarangan, lalu lintas kendaraan sebagai variabel dumi. Analisis regresi digunakan untuk mengukur pengaruh dari atribut terhadap kecelakaan. Hasilnya menunjukkan pintu gerbang, pejalan kaki, dan lokasi tanda perlintasan mempunyai dampak signifikan pada kecelakaan dalam kota metropolis Lagos.Berdasarkan penemuan tersebut, perbaikan dari sistem peringatan aktif disarankan sebagai upaya

  10. Heat shrinkable behavior, physico-mechanical and structure properties of electron beam cross-linked blends of high-density polyethylene with acrylonitrile-butadiene rubber

    International Nuclear Information System (INIS)

    Reinholds, Ingars; Kalkis, Valdis; Merijs-Meri, Remo; Zicans, Janis; Grigalovica, Agnese

    2016-01-01

    In this study, heat-shrinkable composites of electron beam irradiated high-density polyethylene (HDPE) composites with acrylonitrile-butadiene rubber (NBR) were investigated. HDPE/NBR blends at a ratio of components 100/0, 90/10, 80/20, 50/50 and 20/80 wt% were prepared using a two-roll mill. The compression molded films were irradiated high-energy (5 MeV) accelerated electrons up to irradiation absorbed doses of 100–300 kGy. The effect of electron beam induced cross-linking was evaluated by the changes of mechanical properties, gel content and by the differences of thermal properties, detected by differential scanning calorimetry. The thermo-shrinkage forces were determined as the kinetics of thermorelaxation and the residual shrinkage stresses of previously oriented (stretched up to 100% at above melting temperature of HDPE and followed by cooling to room temperature) specimens of irradiated HDPE/NBR blends under isometric heating–cooling mode. The compatibility between the both components was enhanced due to the formation of cross-linked sites at amorphous interphase. The results showed increase of mechanical stiffness of composites with increase of irradiation dose. The values of gel fraction compared to thermorelaxation stresses increased with the growth of irradiation dose level, as a result of formation cross-linked sites in amorphous PP/NBR interphase. - Highlights: • Binary blends of HDPE/NBR have been irradiated with 5 MeV accelerated electrons. • Increase of NBR content and irradiation dose improves cross-linking efficiency. • Thermo-shrinkage and residual stresses are investigated for oriented specimens. • Cross-linked HDPE/NBR composites can be successfully used as thermos-shrinkable materials.

  11. Single-molecule electron tunnelling through multiple redox levels with environmental relaxation

    DEFF Research Database (Denmark)

    Kuznetsov, A.M.; Ulstrup, Jens

    2004-01-01

    represent the substrate and tip in electrochemical in situ scanning tunnelling microscopy. An equivalent three-electrode configuration represents a molecular single-electron transistor in which the enclosing electrodes constitute source and drain, and the reference electrode the gate. Current-bias voltage...... relations at fixed electrochemical overpotential or gate voltage, and current-overpotential or current-gate voltage relations at fixed bias voltage are equivalent in the two systems. Due to the activation-less nature of the processes, electron flow between the electrodes through the molecular redox levels...... level(s) subsequent to electron transfer. Several physical mechanisms can be distinguished and distinctive current-overpotential/gate voltage or current-bias voltage relations obtained. These reflect electronic level separation, environmental nuclear reorganisation, and coherent or incoherent multi...

  12. Laser resolution of unpolarized-electron scattering cross sections into spin-conserved and spin-flip components

    International Nuclear Information System (INIS)

    Ritchie, B.

    1981-01-01

    The theory is presented for one-photon free-free absorption by electrons scattering from high-Z atoms. The absorption cross section provides sufficient information to resolve the unpolarized-electron total cross section, Vertical Barf(theta)Vertical Bar 2 +Vertical Barg(theta)Vertical Bar 2 , into its individual components for spin-nonflip, Vertical Barf(theta)Vertical Bar 2 , and spin-flip, Vertical Barg(theta)Vertical Bar 2 , scattering. The observation of a spin-polarization effect for a spin-independent process (free-free absorption) is analogous to the Fano effect for bound-free absorption

  13. Electron stripping cross sections for light impurity ions in colliding with atomic hydrogens relevant to fusion research

    International Nuclear Information System (INIS)

    Tawara, H.

    1992-04-01

    Electron stripping (ionization) cross sections for impurity (carbon) ions with various charge states in collisions with atomic hydrogens have been surveyed. It has been found that these data are relatively limited both in collision energy and charge state and, in particular those necessary for high energy neutral beam injection (NBI) heating in fusion plasma research are scarce. Some relevant cross sections for carbon ions, C q+ (q = 0-5) have been estimated, based upon the existing data, empirical behavior and electron impact ionization data. (author)

  14. Cross-section and rate coefficient calculation for electron impact excitation, ionisation and dissociation of H2 and OH molecules

    International Nuclear Information System (INIS)

    Riahi, R.; Ben Lakhdar, Z.; Teulet, Ph.; Gleizes, A.

    2006-01-01

    The weighted total cross-sections (WTCS) theory is used to calculate electron impact excitation, ionization and dissociation cross-sections and rate coefficients of OH, H 2 , OH + , H 2 + , OH - and H 2 - diatomic molecules in the temperature range 1500-15000 K. Calculations are performed for H 2 (X, B, C), OH(X, A, B), H 2 + (X), OH + (X, a, A, b, c), H 2 - (X) and OH - (X) electronic states for which Dunham coefficients are available. Rate coefficients are calculated from WTCS assuming Maxwellian energy distribution functions for electrons and heavy particles. One and 2 temperatures (θ e and θ g respectively for electron and heavy particles kinetic temperatures) results are presented and fitting parameters (a, b and c) are given for each reaction rate coefficient: k(θ) a(θ b )exp(-c/θ). (authors)

  15. Total cross sections for slow-electron (1--20 eV) scattering in solid H2O

    International Nuclear Information System (INIS)

    Michaud, M.; Sanche, L.

    1987-01-01

    An analytical method is proposed to determine absolute total cross sections per scatterer and related mean free paths for low-energy electron scattering in disordered molecular solid films. The procedure is based on a two-stream multiple-scattering model of the thickness dependence of the film reflectivity for elastic electrons. The expected analytical behavior and accuracy are tested on a model sample whose scattering properties are generated by a Monte Carlo simulation from initially known parameters. The effects of multiple scattering inside the film and at its interfaces are taken into account and discussed. The thickness dependence of the elastic electron reflectivity of H 2 O film condensed at 14 K is reported between 1 and 20 eV incident energy with a spectrometer resolution of 10 MeV. The proposed method is applied to extract from these measurements the energy dependence of the total effective and total inelastic cross sections for electron scattering in amorphous ice

  16. A State-Space Approach to Optimal Level-Crossing Prediction for Linear Gaussian Processes

    Science.gov (United States)

    Martin, Rodney Alexander

    2009-01-01

    In many complex engineered systems, the ability to give an alarm prior to impending critical events is of great importance. These critical events may have varying degrees of severity, and in fact they may occur during normal system operation. In this article, we investigate approximations to theoretically optimal methods of designing alarm systems for the prediction of level-crossings by a zero-mean stationary linear dynamic system driven by Gaussian noise. An optimal alarm system is designed to elicit the fewest false alarms for a fixed detection probability. This work introduces the use of Kalman filtering in tandem with the optimal level-crossing problem. It is shown that there is a negligible loss in overall accuracy when using approximations to the theoretically optimal predictor, at the advantage of greatly reduced computational complexity. I

  17. Comparison of the potentials used for the calculation of the resonant coherent electron capture and loss cross sections

    International Nuclear Information System (INIS)

    Pauly, N.; Dubus, A.; Roesler, M.

    2003-01-01

    For incident protons with velocities around 1 a.u., electron capture and loss processes are known to play an important role. In particular, electron emission as well as electronic stopping power are strongly influenced by the charge changing processes. Several different electron capture and loss processes have been identified [Solid State Phys. 43 (1990) 229], i.e. Auger valence band processes, shell processes and resonant coherent processes. In the latter, the incident projectile undergoes a periodic excitation due to the periodic crystalline potential so that an electron can be lost or captured. In the literature, several different choices have been made for the crystalline potential. It is precisely the aim of the present work to review and compare the various potentials used in the literature and to show the influence of this choice on the resonant coherent electron capture and loss cross sections

  18. Cross flow filtration of Oak Ridge National Laboratory liquid low-level waste

    International Nuclear Information System (INIS)

    Fowler, V.L.; Hewitt, J.D.

    1989-12-01

    A new method for disposal of Oak Ridge National Laboratory liquid low-level radioactive waste is being developed as an alternative to hydrofracture. The acceptability of the final waste form rests in part on the presence or absence of transuranic (TRU) isotopes. Inertial cross flow filtration was used in this study to determine the potential of this method for separation of the TRU isotopes from the bulk liquid stored in the Melton Valley Storage Tanks. 7 refs., 11 figs., 5 tabs

  19. Spin dynamics at level crossing in molecular AF rings probed by NMR

    Energy Technology Data Exchange (ETDEWEB)

    Lascialfari, A. E-mail: lascialfari@fisicavolta.unipv.it; Borsa, F.; Julien, M.-H.; Micotti, E.; Furukawa, Y.; Jang, Z.H.; Cornia, A.; Gatteschi, D.; Horvatic, M.; Van Slageren, J

    2004-05-01

    The low-temperature spin dynamics in molecular rings with a finite number (N{<=}10) of magnetic ions was studied by means of {sup 1}H NMR. When an external magnetic field (B) induces a crossing between energy levels, peaks are observed in the spin-lattice relaxation rate of protons, 1/T{sub 1}(B), at constant temperature. We discuss similarities and differences in the data from three different rings: Fe10, Fe6:Li and Cr8.

  20. Spin dynamics at level crossing in molecular AF rings probed by NMR

    International Nuclear Information System (INIS)

    Lascialfari, A.; Borsa, F.; Julien, M.-H.; Micotti, E.; Furukawa, Y.; Jang, Z.H.; Cornia, A.; Gatteschi, D.; Horvatic, M.; Van Slageren, J.

    2004-01-01

    The low-temperature spin dynamics in molecular rings with a finite number (N≤10) of magnetic ions was studied by means of 1 H NMR. When an external magnetic field (B) induces a crossing between energy levels, peaks are observed in the spin-lattice relaxation rate of protons, 1/T 1 (B), at constant temperature. We discuss similarities and differences in the data from three different rings: Fe10, Fe6:Li and Cr8

  1. Servant leadership and employee voice behavior: a cross-level investigation in China

    OpenAIRE

    Yan, Aimin; Xiao, Yigui

    2016-01-01

    This study tested the influence and mechanisms of servant leadership on voice behavior, including the mediating role of psychological safety, and the moderating role of supervisor-subordinate Guanxi. Data were collected from 430 civil servants and their immediate supervisors in Changsha, China. Cross-Level investigation revealed that servant leadership had a significant influence on voice behavior, psychological safety mediated the relationship between servant leadership and voice behavior, w...

  2. Two Dimensional Effective Electron Mass at the Fermi Level in Quantum Wells of III-V, Ternary and Quaternary Semiconductors.

    Science.gov (United States)

    Chakrabarti, S; Chatterjee, B; Debbarma, S; Ghatak, K P

    2015-09-01

    In this paper we study the influence of strong electric field on the two dimensional (2D)effective electron mass (EEM) at the Fermi level in quantum wells of III-V, ternary and quaternary semiconductors within the framework of k x p formalism by formulating a new 2D electron energy spectrum. It appears taking quantum wells of InSb, InAs, Hg(1-x)Cd(x)Te and In(1-x)Ga(x)As(1-y)P(y) lattice matched to InP as examples that the EEM increases with decreasing film thickness, increasing electric field and increases with increasing surface electron concentration exhibiting spikey oscillations because of the crossing over of the Fermi level by the quantized level in quantum wells and the quantized oscillation occurs when the Fermi energy touches the sub-band energy. The electric field makes the mass quantum number dependent and the oscillatory mass introduces quantum number dependent mass anisotropy in addition to energy. The EEM increases with decreasing alloy composition where the variations are totally band structure dependent. Under certain limiting conditions all the results for all the cases get simplified into the well-known parabolic energy bands and thus confirming the compatibility test. The content of this paper finds three applications in the fields of nano-science and technology.

  3. Molecular design of new P3HT derivatives: Adjusting electronic energy levels for blends with PCBM

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Eliezer Fernando [UNESP – Univ Estadual Paulista, POSMAT – Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, Bauru, SP (Brazil); Lavarda, Francisco Carlos, E-mail: lavarda@fc.unesp.br [UNESP – Univ Estadual Paulista, POSMAT – Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, Bauru, SP (Brazil); Faculdade de Ciências, UNESP – Univ Estadual Paulista, Departamento de Física, Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, 17033-360 Bauru, SP (Brazil)

    2014-12-15

    An intensive search is underway for new materials to make more efficient organic solar cells through improvements in thin film morphology, transport properties, and adjustments to the energy of frontier electronic levels. The use of chemical modifications capable of modifying the electronic properties of materials already known is an interesting approach, as it can, in principle, provide a more adequate adjustment of the frontier electronic levels while preserving properties such as solubility. Based on this idea, we performed a theoretical study of poly(3-hexylthiophene) (P3HT) and 13 new derivatives obtained by substitution with electron acceptor and donor groups, in order to understand how the energy levels of the frontier orbitals are modified. The results show that it is possible to deduce the modification of the electronic levels in accordance with the substituent's acceptor/donor character. We also evaluated how the substituents influence the open circuit voltage and the exciton binding energy. - Highlights: • Prediction of P3HT derivatives properties for bulk-heterojunction solar cells. • Correlating substituent properties with electronic levels of P3HT derivatives. • Fluorinated P3HT improves open circuit voltage and stability.

  4. Serum IFN neutralizing antibodies and neopterin levels in a cross-section of MS patients.

    Science.gov (United States)

    Cook, S D; Quinless, J R; Jotkowitz, A; Beaton, P

    2001-09-25

    To determine levels of serum interferon beta (IFNbeta) neutralizing antibody (NAb) and neopterin-an IFN biologic response marker-in patients with MS treated with Betaseron or Avonex. Controversy exists over the relative immunogenicity of IFNbeta-1a and IFNbeta-1b and the reasons for any such difference. To determine the role of patient profile and test methodology in IFNbeta, NAb levels need to be measured blindly and simultaneously in a predefined closely matched MS patient cohort. Serum NAb and neopterin levels were measured in closely matched patients on Avonex (n = 98) or Betaseron (n = 64). NAb were determined by Athena Diagnostics and serum neopterin levels by Covance Laboratories using a competitive binding radioimmunoassay. More patients taking Betaseron (22%) than Avonex (7%) had elevated titers of NAb (p = 0.008). Mean serum neopterin levels were lower in patients with high as compared to low NAb titers (p = 0.0002). No difference in mean neopterin levels was found comparing the total Betaseron group to the Avonex group; however, in the subset of patients with low NAb titers, mean neopterin levels were higher in the Betaseron than in the Avonex group (p = 0.027). A random cross-sectional sampling of patients on Avonex showed a decrease in neopterin levels over time between weekly doses. NAb are more commonly found with Betaseron than Avonex. More studies are needed to determine the correlation among serum neopterin levels, other biologic response markers, NAb, and disease activity in patients with MS being treated with IFNbeta.

  5. Relationship between Plasma Ghrelin Levels and Sarcopenia in Elderly Subjects: A Cross-Sectional Study.

    Science.gov (United States)

    Serra-Prat, M; Papiol, M; Monteis, R; Palomera, E; Cabré, M

    2015-06-01

    The aim of this study was to investigate the relationship between plasma ghrelin levels and sarcopenia in elderly people. Cross-sectional study. Health consortium medical centers in the Maresme region, Barcelona (Spain). Two groups of subjects: persons ≥70 years (elderly group) and persons 25-65 years (young adults). Sarcopenia, diagnosed according to the EWGSOP definition, fasting and postprandial plasma ghrelin levels, body composition, hand grip, Barthel score, and frailty using Fried criteria. Fifty-five elderly subjects and 33 young adults were recruited. In both age groups, mean ghrelin levels were significantly higher in women than in men. However, mean ghrelin levels were similar in elderly and young men (716 vs. 752 pg mL-1, P = 0.763) as well as in elderly and young women (859 vs. 995 pg mL-1, P = 0.190). In the elderly group, subjects with sarcopenia showed significantly lower ghrelin levels than those without sarcopenia (650 vs. 899 pg mL-1, P = 0.036), but these differences disappeared when stratifying by gender. Elderly subjects without sarcopenia had the same ghrelin levels as young adults (899.3 vs. 899.6 pg mL-1). In young women, ghrelin levels correlated with fat free mass (rs = 0.58, P = 0.007) and muscular mass (rs = 0.54, P = 0.015) but these correlations were not observed in men nor in elderly women. This cross-sectional study does not allow a definitive conclusion about the relationship between ghrelin levels and sarcopenia. Further large prospective studies are needed to test this hypothesis.

  6. Partial and total electronic stopping cross sections of atoms for a singly charged helium ion, Part 2

    International Nuclear Information System (INIS)

    Kaneko, T.; Nishikori, M.; Yamato, N.

    1991-08-01

    Partial and total electronic stopping cross sections of atoms with Z (55 ≤ Z ≤ 92) for a He + ion are tabulated as the second part of NIFS-DATA-11 (1991) on the basis of the wave-packet theory. (author)

  7. Heat shrinkable behavior, physico-mechanical and structure properties of electron beam cross-linked blends of high-density polyethylene with acrylonitrile-butadiene rubber

    Science.gov (United States)

    Reinholds, Ingars; Kalkis, Valdis; Merijs-Meri, Remo; Zicans, Janis; Grigalovica, Agnese

    2016-03-01

    In this study, heat-shrinkable composites of electron beam irradiated high-density polyethylene (HDPE) composites with acrylonitrile-butadiene rubber (NBR) were investigated. HDPE/NBR blends at a ratio of components 100/0, 90/10, 80/20, 50/50 and 20/80 wt% were prepared using a two-roll mill. The compression molded films were irradiated high-energy (5 MeV) accelerated electrons up to irradiation absorbed doses of 100-300 kGy. The effect of electron beam induced cross-linking was evaluated by the changes of mechanical properties, gel content and by the differences of thermal properties, detected by differential scanning calorimetry. The thermo-shrinkage forces were determined as the kinetics of thermorelaxation and the residual shrinkage stresses of previously oriented (stretched up to 100% at above melting temperature of HDPE and followed by cooling to room temperature) specimens of irradiated HDPE/NBR blends under isometric heating-cooling mode. The compatibility between the both components was enhanced due to the formation of cross-linked sites at amorphous interphase. The results showed increase of mechanical stiffness of composites with increase of irradiation dose. The values of gel fraction compared to thermorelaxation stresses increased with the growth of irradiation dose level, as a result of formation cross-linked sites in amorphous PP/NBR interphase.

  8. Method for Pedestrian Crossing Risk Assessment and Safety Level Determination: the Case Study of Tallinn

    Energy Technology Data Exchange (ETDEWEB)

    Pashkevich, M.; Krasilnikova, A.; Antov, D.

    2016-07-01

    Pedestrians are a part of vulnerable road users which safety requires a special attention. Official statistics in Estonia from the last decade returns the following numbers: around 30 % of all road traffic accidents in the country were accidents with pedestrians, 32 % of all traffic fatalities were finished with pedestrian death. Pedestrian crossing has the biggest risk level between all kinds of pedestrian facilities, because it includes a direct conflict point between vehicle and pedestrian traffics. The article presents a method to assess risk of pedestrian crossing users and to determine safety level of this road infrastructure element. This approach is based on observation and collection of infrastructural as well as traffic data, which includes: (1) information about each pedestrian crossing facility, its location and state, (2) data about accidents with pedestrians and their features, (3) data from road traffic measurements. The main advantages of the described method are universality and comprehensiveness. The case study was done in Kristiine district of the city Tallinn, which was chosen as the most typical average district of Estonian capital. Results of this study are also presented in the article. (Author)

  9. Noise Levels in Two Emergency Departments Before and After the Introduction of Electronic Whiteboards

    DEFF Research Database (Denmark)

    Hertzum, Morten

    2013-01-01

    . The maximum equivalent continuous noise levels across 1 second were above 80 dB(A) at all four coordination centres. At two of the centres above 80 dB(A) noises also occurred at night. After the introduction of electronic whiteboards the noise level was lowered at one ED but unchanged at the other ED...

  10. Spectroscopic analysis of electron trapping levels in pentacene field-effect transistors

    International Nuclear Information System (INIS)

    Bum Park, Chang

    2014-01-01

    Electron trapping phenomena have been investigated with respect to the energy levels of localized trap states and bias-induced device instability effects in pentacene field-effect transistors. The mechanism of the photoinduced threshold voltage shift (ΔV T ) is presented by providing a ΔV T model governed by the electron trapping. The trap-and-release behaviour functionalized by photo-irradiation also shows that the trap state for electrons is associated with the energy levels in different positions in the forbidden gap of pentacene. Spectroscopic analysis identifies two kinds of electron trap states distributed above and below the energy of 2.5 eV in the band gap of the pentacene crystal. The study of photocurrent spectra shows the specific trap levels of electrons in energy space that play a substantial role in causing device instability. The shallow and deep trapping states are distributed at two centroidal energy levels of ∼1.8 and ∼2.67 eV in the pentacene band gap. Moreover, we present a systematic energy profile of electron trap states in the pentacene crystal for the first time. (paper)

  11. Electron drift velocities in He and water mixtures: Measurements and an assessment of the water vapour cross-section sets

    International Nuclear Information System (INIS)

    Urquijo, J. de; Juárez, A. M.; Basurto, E.; Ness, K. F.; Robson, R. E.; White, R. D.; Brunger, M. J.

    2014-01-01

    The drift velocity of electrons in mixtures of gaseous water and helium is measured over the range of reduced electric fields 0.1–300 Td using a pulsed-Townsend technique. Admixtures of 1% and 2% water to helium are found to produce negative differential conductivity (NDC), despite NDC being absent from the pure gases. The measured drift velocities are used as a further discriminative assessment on the accuracy and completeness of a recently proposed set of electron-water vapour cross-sections [K. F. Ness, R. E. Robson, M. J. Brunger, and R. D. White, J. Chem. Phys. 136, 024318 (2012)]. A refinement of the momentum transfer cross-section for electron-water vapour scattering is presented, which ensures self-consistency with the measured drift velocities in mixtures with helium to within approximately 5% over the range of reduced fields considered

  12. Doubly differential cross sections of low-energy electrons emitted in the ionization of molecular hydrogen by bare carbon ions

    International Nuclear Information System (INIS)

    Tribedi, L.C.; Richard, P.; Ling, D.; Wang, Y.D.; Lin, C.D.; Moshammer, R.; Kerby, G.W. III; Gealy, M.W.; Rudd, M.E.

    1996-01-01

    We have measured the double differential cross sections (DDCS) (d 2 σ/d var-epsilon ed Ω e ) of low-energy electron emission in the ionization of H 2 bombarded by bare carbon ions of energy 30 MeV. The energy and angular distributions of the electron DDCS have been obtained for 12 different emission angles and for electron energies varying between 0.1 and 300 eV. We have also deduced the single differential and total ionization cross section from the measured DDCS. The data have been compared with the predictions of first Born approximations and the CDW-EIS (continuum distorted wave endash eikonal initial state) model. The CDW-EIS model provides an excellent agreement with the data. copyright 1996 The American Physical Society

  13. Cross-Calibration of Secondary Electron Multiplier in Noble Gas Analysis

    Science.gov (United States)

    Santato, Alessandro; Hamilton, Doug; Deerberg, Michael; Wijbrans, Jan; Kuiper, Klaudia; Bouman, Claudia

    2015-04-01

    The latest generation of multi-collector noble gas mass spectrometers has decisively improved the precision in isotopic ratio analysis [1, 2] and helped the scientific community to address new questions [3]. Measuring numerous isotopes simultaneously has two significant advantages: firstly, any fluctuations in signal intensity have no effect on the isotope ratio and secondly, the analysis time is reduced. This particular point becomes very important in static vacuum mass spectrometry where during the analysis, the signal intensity decays and at the same time the background increases. However, when multi-collector analysis is utilized, it is necessary to pay special attention to the cross calibration of the detectors. This is a key point in order to have accurate and reproducible isotopic ratios. In isotope ratio mass spectrometry, with regard to the type of detector (i.e. Faraday or Secondary Electron Multiplier, SEM), analytical technique (TIMS, MC-ICP-MS or IRMS) and isotope system of interest, several techniques are currently applied to cross-calibrate the detectors. Specifically, the gain of the Faraday cups is generally stable and only the associated amplifier must be calibrated. For example, on the Thermo Scientific instrument control systems, the 1011 and 1012 ohm amplifiers can easily be calibrated through a fully software controlled procedure by inputting a constant electric signal to each amplifier sequentially [4]. On the other hand, the yield of the SEMs can drift up to 0.2% / hour and other techniques such as peak hopping, standard-sample bracketing and multi-dynamic measurement must be used. Peak hopping allows the detectors to be calibrated by measuring an ion beam of constant intensity across the detectors whereas standard-sample bracketing corrects the drift of the detectors through the analysis of a reference standard of a known isotopic ratio. If at least one isotopic pair of the sample is known, multi-dynamic measurement can be used; in this

  14. Electron capture cross sections by O{sup +} from atomic He

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Dwayne C; Saha, Bidhan C [Department of Physics, Florida A and M University, Tallahassee, FL-32307 (United States)

    2009-11-01

    The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections

  15. The levels of the first excited configuration of one-electron ions in intensive alternating field

    International Nuclear Information System (INIS)

    Klimchitskaya, G.L.

    1984-01-01

    The relativistic generalization of the quasi-energy method is applied for the calculation of the influence of spatjally-homogeneous electric field with the periodic time dependence on the energy levels of the first excited configuration of one-electron multiply charged ions. The dependence is found of the corresponding quasi-energy levels on the amplitude and frequency of intensive external field which wholly mixes the levels of fine structure

  16. A semi-empirical concept for the calculation of electron-impact ionization cross sections of neutral and ionized fullerenes

    International Nuclear Information System (INIS)

    Deutsch, H.; Scheier, P.; Maerk, T.D.; Becker, K.

    2002-01-01

    A semi-empirical approach to the calculation of cross section functions (absolute value and energy dependence) for the electron-impact ionization of several neutral and ionized fullerenes C 60 n+ (n =0-3) was developed, for which reliable experimental data have been reported. In particular, it is proposed a modification of the simplistic assumption that the ionization cross section of a cluster/fullerene is given as the product of the monomer ionization cross section and a factor m a , where 'm' is the number of monomers in the ensemble and 'a' is a constant. A comparison between these calculations and the available experimental data reveals good agreement for n = 0,103. In the case of ionization of C 60 2+ (n = 2) the calculation lies significantly below the measured cross section which it was interpret as an indication that additional indirect ionization processes are present for this charge state. (nevyjel)

  17. Nuclear level density effects on the evaluated cross-sections of nickel isotopes

    International Nuclear Information System (INIS)

    Garg, S.B.

    1995-01-01

    A detailed investigation has been made to estimate the effect of various level density options on the computed neutron induced reaction cross-sections of Ni-58 and Ni-60 covering the energy range 5-25 MeV in the framework of the multistep Hauser-Feshbach statistical model scheme which accounts for the pre-equilibrium decay according to the Kalbach exciton model and gamma-ray competition according to the giant dipole radiation model of Brink and Axel. Various level density options considered in this paper are based on the Original Gilbert-Cameron, Improved Gilbert-Cameron, Back-Shifted Fermi gas and the Ingatyuk-Smirenkin-Tishin approaches. The effect of these different level density prescriptions is brought out with special reference to (n,p) (n,2n) (n,α) and total production cross-sections for neutron, hydrogen, helium and gamma-rays which are of technological importance for fission and fusion based reactor systems. (author). 18 refs, 2 figs

  18. Highly accurate nuclear and electronic stopping cross sections derived using Monte Carlo simulations to reproduce measured range data

    Science.gov (United States)

    Wittmaack, Klaus; Mutzke, Andreas

    2017-03-01

    We have examined and confirmed the previously unexplored concept of using Monte Carlo calculations in combination with measured projected ranges of ions implanted in solids to derive a quantitative description of nuclear interaction and electronic stopping. The study involved 98 ranges of 11B in Si between 1 keV and 8 MeV, contained in 12 sets of 10 different groups. Systematic errors by up to ±8% were removed to establish a refined data base with 93 ranges featuring only statistical uncertainties (±1.8%). The Monte Carlo calculations could be set up to reproduce the refined ranges with a mean ratio 1.002 ± 1.7%. The input parameters required for this very high level of agreement are as follows. Nuclear interaction is best described by the Kr-C potential, but in obligatory combination with the Lindhard-Scharff (LS) screening length. Up to 300 keV, the electronic stopping cross section is proportional to the projectile velocity, Se = kSe,LS, with k = 1.46 ± 0.01. At higher energies, Se falls progressively short of kSe,LS. Around the Bragg peak, i.e., between 0.8 and 10 MeV, Se is modeled by an adjustable function serving to tailor the peak shape properly. Calculated and measured isotope effects for ranges of 10B and 11B in Si agree within the experimental uncertainty (±0.25%). The range-based Se,R(E) reported here predicts the scarce experimental data derived from the energy loss in projectile transmission through thin Si foils to within 2% or better. By contrast, Se(E) data of available stopping power tables exhibit deviations from Se,R(E) between -40% and +14%.

  19. Nuclear hyperfine structure of muonium in CuCl resolved by means of avoided level crossing

    International Nuclear Information System (INIS)

    Schneider, J.W.; Celio, M.; Keller, H.; Kuendig, W.; Odermatt, W.; Puempin, B.; Savic, I.M.; Simmler, H.; Estle, T.L.; Schwab, C.; Kiefl, R.F.; Renker, D.

    1990-01-01

    We report detailed avoided-level-crossing spectra of a muonium center (Mu II ) in single-crystal CuCl in a magnetic field range of 4--5 T and at a temperature of 100 K. The hyperfine parameters of the muon and the closest two shells of nuclei indicate that this center consists of muonium at a tetrahedral interstice with four Cu nearest neighbors and six Cl next-nearest neighbors and that the spin density is appreciable on the muon and on the ten neighboring nuclei but negligible elsewhere

  20. Servant leadership and employee voice behavior: a cross-level investigation in China.

    Science.gov (United States)

    Yan, Aimin; Xiao, Yigui

    2016-01-01

    This study tested the influence and mechanisms of servant leadership on voice behavior, including the mediating role of psychological safety, and the moderating role of supervisor-subordinate Guanxi. Data were collected from 430 civil servants and their immediate supervisors in Changsha, China. Cross-Level investigation revealed that servant leadership had a significant influence on voice behavior, psychological safety mediated the relationship between servant leadership and voice behavior, while supervisor-subordinate Guanxi negatively moderated the relationship between servant leadership and voice behavior.

  1. Association between serum alpha-fetoprotein levels and fatty liver disease: A cross-sectional study

    Science.gov (United States)

    Xu, Ping; Xu, Cheng-Fu; Wan, Xing-Yong; Yu, Chao-Hui; Shen, Chao; Chen, Peng; Xu, Gen-Yun; Li, You-Ming

    2014-01-01

    AIM: To investigate the association between serum alpha-fetoprotein (AFP) levels and fatty liver disease (FLD) in a Chinese population. METHODS: A cross-sectional study was performed among subjects who presented for a health examination at the First Affiliated Hospital, College of Medicine, Zhejiang University in 2013. FLD was diagnosed based on an ultrasonography examination. Serum AFP levels were measured with a chemiluminescence immunoassay. RESULTS: Of the 9800 subjects enrolled, 2601 were diagnosed with FLD. Subjects with FLD had higher serum AFP levels than those without the disease. Subjects with high serum AFP levels had a higher prevalence of FLD, metabolic syndrome, and its components. Univariate logistic analysis showed that elevated serum AFP levels were associated with an increased risk of FLD (OR = 1.057, 95%CI: 1.031-1.084). However, after adjusting for covariates, AFP no longer remained significantly associated with the risk factors for FLD. CONCLUSION: Our results suggest that serum AFP levels are significantly associated with FLD and that AFP acts as a cofactor, but not as an independent factor, for FLD. PMID:25206293

  2. Plasma lipid levels in Alzheimer's disease patients treated by Donepezil hydrochloride: a cross-sectional study.

    Science.gov (United States)

    Adunsky, Abraham; Chesnin, Vladimir; Ravona, Ramit; Harats, Dror; Davidson, Michael

    2004-01-01

    Donepezil hydrochloride is a central acetylcholine esterase inhibitor that is widely used in Alzheimer disease (AD). We have recently observed some differences in lipid profile between occasional cases of Donepezil hydrochloride users (DU) and non-users (DNU). This prompted us to study the levels of plasma lipids in these two groups, cross-sectionally. The medical charts of patients with probable AD were screened for current use of Donepezil hydrochloride and lipids profile, along with other clinical and demographic data. A total number of 105 patients were identified and included in the final analysis. Patients were divided into two groups (DU and DNU). Plasma levels of lipids were recorded. Mann-Whitney or t-test for continuous variables and Fisher exact test for categorical variables were used to test for significant differences between the groups. Regression analysis was applied to identify independently the factors associated with lipid levels. Thirty-three patients were DU and 72 DNU. The two groups differed in terms of age, lipid levels and cognitive level. DU had statistically significant higher levels of triglycerides compared with those not using the drug (P=0.036), higher total cholesterol (Phydrochloride. Alternatively, this may indicate that the effect of the medication may involve lipid metabolism, rather than other proposed mechanisms.

  3. Electrons and photons at High Level Trigger in CMS for Run II

    CERN Document Server

    Bin Anuar, Afiq Aizuddin

    2015-01-01

    The CMS experiment has been designed with a 2-level trigger system. The first level is implemented using custom-designed electronics. The second level is the so-called High Level Trigger (HLT), a streamlined version of the CMS offline reconstruction software running on a computer farm. For Run II of the Large Hadron Collider, the increase in center-of-mass energy and luminosity will raise the event rate to a level challenging for the HLT algorithms. New approaches have been studied to keep the HLT output rate manageable while maintaining thresholds low enough to cover physics analyses. The strategy mainly relies on porting online the ingredients that have been successfully applied in the offline reconstruction, thus allowing to move HLT selection closer to offline cuts. Improvements in HLT electron and photon definitions will be presented, focusing in particular on updated clustering algorithm and the energy calibration procedure, new Particle-Flow-based isolation approach and pileup mitigation techniques, a...

  4. Ab initio calculation of scattering length and cross sections at very low energies for electron-helium scattering

    International Nuclear Information System (INIS)

    Saha, H.P.

    1993-01-01

    The multiconfiguration Hartree-Fock method for continuum wave functions has been used to calculate the scattering length and phase shifts over extremely low energies ranging from 0 to 1 eV very accurately for electron-helium scattering. The scattering length is calculated very accurately with wave functions computed exactly at zero energy, resulting in an upper bound of 1.1784. The electron correlation and polarization of the target by the scattering electron, which are very important in these calculations, have been taken into account in an accurate ab initio manner through the configuration-interaction procedure by optimizing both bound and continuum orbitals simultaneously at each kinetic energy of the scattered electron. Detailed results for scattering length, differential, total, and momentum-transfer cross sections obtained from the phase shifts are presented. The present scattering length is found to be in excellent agreement with the experimental result of Andrick and Bitsch [J. Phys. B 8, 402 (1975)] and the theoretical result of O'Malley, Burke, and Berrington [J. Phys. B 12, 953 (1979)]. There is excellent agreement between the present total cross sections and the corresponding experimental measurements of Buckman and Lohmann [J. Phys. B 19, 2547 (1986)]. The present momentum-transfer cross sections also show remarkable agreement with the experimental results of Crompton, Elford, and Robertson [Aust. J. Phys. 23, 667 (1970)

  5. Measurement of charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, IL (US)] (and others)

    2008-12-15

    Measurements of the cross sections for charged current deep inelastic scattering in e{sup -}p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb{sup -1} collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections d{sigma}/dQ{sup 2}, d{sigma}/dx and d{sigma}/dy are presented for Q{sup 2}>200 GeV{sup 2}. The double-differential cross-section d{sup 2}{sigma}/dxdQ{sup 2} is presented in the kinematic range 280cross sections are compared with the predictions of the Standard Model. (orig.)

  6. Calculation of 3-D free electron laser gain: Comparison with simulation and generalization to elliptical cross section

    International Nuclear Information System (INIS)

    Chin, Yong Ho; Kim, Kwang-Je; Xie, Ming.

    1992-08-01

    In the previous paper, we have derived a dispersion relation for the free electron laser (FEL) gain in the exponential regime taking account the diffraction and electron's betatron oscillation. Here, we compare the growth rates obtained by solving the dispersion relation with those obtained by simulation calculation for the waterbag and the Gaussian models for the electron's transverse phase space distribution. The agreement is found to be good except for the limiting case where the Rayleigh length is much longer than the gain length (1-D limit). We also generalize the analysis to the case where the electron beam cross section is elliptical as is usually the case in storage rings, and derive the first-order dispersion relation

  7. Langmuir waves excitation by electron beam with the limited cross-section in the near-earth electron foreshock

    International Nuclear Information System (INIS)

    Anisimov, I.O.; Musatenko, K.S.; Krasnosselskikh, V.V.

    2005-01-01

    Model of the stripped monoenergetic electron beam with the sharp boundaries based on the results of CLUSTER measurements is proposed for the near-Earth foreshock vicinity. Dispersion equation is obtained and analyzed using numerical methods. Dependency of the equation roots corresponding to kinetic mechanism of beam-plasma instability on the model parameters is studied

  8. Learning Object Names at Different Hierarchical Levels Using Cross-Situational Statistics.

    Science.gov (United States)

    Chen, Chi-Hsin; Zhang, Yayun; Yu, Chen

    2018-05-01

    Objects in the world usually have names at different hierarchical levels (e.g., beagle, dog, animal). This research investigates adults' ability to use cross-situational statistics to simultaneously learn object labels at individual and category levels. The results revealed that adults were able to use co-occurrence information to learn hierarchical labels in contexts where the labels for individual objects and labels for categories were presented in completely separated blocks, in interleaved blocks, or mixed in the same trial. Temporal presentation schedules significantly affected the learning of individual object labels, but not the learning of category labels. Learners' subsequent generalization of category labels indicated sensitivity to the structure of statistical input. Copyright © 2017 Cognitive Science Society, Inc.

  9. Regional specific groundwater arsenic levels and neuropsychological functioning: a cross-sectional study.

    Science.gov (United States)

    Edwards, Melissa; Johnson, Leigh; Mauer, Cortney; Barber, Robert; Hall, James; O'Bryant, Sid

    2014-01-01

    The purpose of the study was to examine the link between geographic information system (GIS)-estimated regional specific groundwater levels and neuropsychological functioning in a sample of individuals with and without cognitive impairment. This cross-sectional study design analyzed data from 1390 participants (733 Alzheimer's disease, 127 Mild Cognitive Impairment, and 530 with normal cognition) enrolled in the Texas Alzheimer's Research and Care Consortium. GISs analyses were used to estimate regional specific groundwater arsenic concentrations using the Environmental Systems Research Institute and arsenic concentrations from the Texas Water Development Board. In the full cohort, regional specific arsenic concentrations were positively associated with language abilities (p = 0.008), but associated with poorer verbal memory, immediate (p = 0.008), and delayed (p arsenic being related with cognition most prominently among mild cognitive impairment cases. Overall, estimated regional specific groundwater arsenic levels were negatively associated with neuropsychological performance.

  10. Motivating and demotivating forces in teams: cross-level influences of empowering leadership and relationship conflict.

    Science.gov (United States)

    Chen, Gilad; Sharma, Payal Nangia; Edinger, Suzanne K; Shapiro, Debra L; Farh, Jiing-Lih

    2011-05-01

    Using cross-cultural laboratory and field studies with samples of leaders, employees, and students from the United States and the People's Republic of China, we examined how team-level stimuli, including empowering leadership and relationship conflict, combine to influence individual members' motivational states of psychological empowerment and affective commitment. As predicted, we found that these motivational states are individually and jointly influenced by teams' level of empowering leadership and relationship conflict and that these motivational states mediate the relationships between team stimuli and team members' innovative and teamwork behaviors and turnover intentions. In addition, results held despite controlling for team members' nationality and collectivism. We discuss contributions of our study to the team motivation, conflict, and stress literatures.

  11. Effect of different level density prescriptions on the calculated neutron nuclear reaction cross sections

    International Nuclear Information System (INIS)

    Garg, S.B.

    1991-01-01

    A detailed investigation is carried out to determine the effect of different level density prescriptions on the computed neutron nuclear data of Ni-58 in the energy range 5-25 MeV. Calculations are performed in the framework of the multistep Hauser-Feshbach statistical theory including the Kalbach exciton model and Brink-Axel giant dipole resonance model for radiative capture. Level density prescriptions considered in this investigation are based on the original Gilbert-Cameron, improved Gilbert-Cameron, backshifted Fermi-gas and the Ignatyuk, et al. approaches. The effect of these prescriptions is discussed, with special reference to (n,p), (n,2n), (n,alpha) and total particle-production cross sections. (author). 17 refs, 8 figs

  12. The impact of power market reforms on electricity price-cost margins and cross-subsidy levels: A cross country panel data analysis

    International Nuclear Information System (INIS)

    Erdogdu, Erkan

    2011-01-01

    One of the main expectations from power market reform has been a reduction in both price-cost margins and cross-subsidy levels between industrial and residential consumers. This paper focuses on this issue by looking at the impact of the electricity industry reforms on residential and industrial electricity price-cost margins and their effect on cross-subsidy levels between consumer groups. Using panel data for 63 developed and developing countries covering the period 1982-2009, empirical models are developed and analyzed. The research findings suggest that there is no uniform pattern for the impact of reform process as a whole on price-cost margins and cross-subsidy levels. Each individual reform step has different impact on price-cost margins and cross-subsidy levels for each consumer and country group. Our findings imply that reform steps have different impacts in different countries, which supports the idea reform prescription for a specific country cannot easily and successfully be transferred to another one. So, transferring the formal and economic structure of a successful power market in a developed country to developing countries is not a sufficient condition for good economic performance of the electricity industries in developing countries. Furthermore, the study suggests that power consumption, income level and country-specific features constitute other important determinants of electricity price-cost margins and cross-subsidy levels. - Research highlights: → The paper focuses on the impact of power market reforms on price-cost margins and cross-subsidy levels. → Using panel data for 63 countries for the period 1982-2009, empirical models are developed and analyzed. → We found that each individual reform step has different impact for each consumer and country group. → We conclude that reform prescription for a specific country cannot easily be transferred to another one.

  13. Total projectile electron loss cross sections of U^{28+} ions in collisions with gaseous targets ranging from hydrogen to krypton

    Directory of Open Access Journals (Sweden)

    G. Weber

    2015-03-01

    Full Text Available Beam lifetimes of stored U^{28+} ions with kinetic energies of 30 and 50  MeV/u, respectively, were measured in the experimental storage ring of the GSI accelerator facility. By using the internal gas target station of the experimental storage ring, it was possible to obtain total projectile electron loss cross sections for collisions with several gaseous targets ranging from hydrogen to krypton from the beam lifetime data. The resulting experimental cross sections are compared to predictions by two theoretical approaches, namely the CTMC method and a combination of the DEPOSIT code and the RICODE program.

  14. Wakefield excitation by a sequence of relativistic electron bunches in dielectric waveguides of rectangular cross-section of various configurations

    International Nuclear Information System (INIS)

    Kiselev, V.A.; Linnik, A.F.; Mirnyj, V.I.; Onishchenko, I.N.; Sotnikov, G.V.; Uskov, V.V.

    2008-01-01

    The possibility to enhance the efficiency of wake wave excitation in dielectric waveguides of rectangular cross-section was investigated by increase of electron bunches coupling with excited wakefield that was achieved by decrease of transit channel cross-section. At that for each configuration the required changes of dielectric plates size were made to for maintain the coincidence concurrence of bunch repetition frequency and frequency of the principal transverse mode of the corresponding dielectric waveguide. It is established, the decrease of transit channel leading to essential changing of topography of total field excited wake wave

  15. Excitation of the 1P and 3P levels of Mg atom by electron impact

    International Nuclear Information System (INIS)

    Avdonina, N.B.; Amus'ya, M.Ya.

    1983-01-01

    Using a diagram method of the many-body theory in the first order of the perturbation theory for the interaction of incident electron and atom expressions for differential and integral excitation cross sections of 3s → 3p 1 P and 3s → 3p 3 P magnesium have been derived. Calculational results are compared with experimental as well as with calculations made in the approximation of a strong coupling. In a wide range of scattering angles good agreement with cross sections measured experimentally has been obtained. Necessity of the diagram consideration of a higher order of the perturbation theory during the investigation of the scattering processes at small angles is concluded on the basis of the above comparison

  16. Direct Identification of Atomic-Like Electronic Levels in InAs Nano crystal Quantum Dots

    International Nuclear Information System (INIS)

    Millo, O.; Katz, D.

    1999-01-01

    The size dependent level structure of InAs nano crystals in the range 2-7 nm in diameter is investigated using both tunneling and optical spectroscopies. The tunneling measurements are performed using a cryogenic scanning tunneling microscope on individual nano crystals that, are attached to a gold substrate via dithiol molecules. The tunneling I-V characteristics manifest an interplay between single electron charging and quantum size effects. We are able to directly identify quantum confined states of isolated InAs nano crystals having s and p symmetries. These states are observed in the I-V curves as two and six-fold single electron charging multiplets. Excellent agreement is found between the strongly allowed optical transitions [1] and the spacing of levels detected in the tunneling experiment. This correlation provides new information on the quantum-dot level structure, from which we conclude that the top-most valence band state has both s and p characteristics. The interplay between level structure singles electron charging of the nano crystals obeys an atomic-like Aufbau sequential electron level occupation

  17. Dynamic correlation of photo-excited electrons: Anomalous levels induced by light–matter coupling

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xiankai [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Huai, Ping, E-mail: huaiping@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800 (China); Song, Bo, E-mail: bosong@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800 (China)

    2014-04-01

    Nonlinear light–matter coupling plays an important role in many aspects of modern physics, such as spectroscopy, photo-induced phase transition, light-based devices, light-harvesting systems, light-directed reactions and bio-detection. However, excited states of electrons are still unclear for nano-structures and molecules in a light field. Our studies unexpectedly present that light can induce anomalous levels in the electronic structure of a donor–acceptor nanostructure with the help of the photo-excited electrons transferring dynamically between the donor and the acceptor. Furthermore, the physics underlying is revealed to be the photo-induced dynamical spin–flip correlation among electrons. These anomalous levels can significantly enhance the electron current through the nanostructure. These findings are expected to contribute greatly to the understanding of the photo-excited electrons with dynamic correlations, which provides a push to the development and application of techniques based on photosensitive molecules and nanostructures, such as light-triggered molecular devices, spectroscopic analysis, bio-molecule detection, and systems for solar energy conversion.

  18. Experimentation and correlates of electronic nicotine delivery system (electronic cigarettes) among university students – A cross sectional study

    OpenAIRE

    K.H. Awan

    2016-01-01

    Objective: E-cigarettes are becoming popular among youth as safe nicotine delivery systems. Many have expressed concern, however, that e-cigarettes may serve as a gateway to future smoking, given their low perceived risk, or that their use may prevent regular smokers from quitting by maintaining their nicotine addiction. The aim of this study was to assess experimentation with and correlates of e-cigarette use among university students. Material and methods: A cross-sectional study was car...

  19. Exploring the cross-level impact of market orientation on nursing innovation in hospitals.

    Science.gov (United States)

    Weng, Rhay-Hung; Huang, Ching-Yuan; Lin, Tzu-En

    2013-01-01

    Recently, many hospitals have been enthusiastically encouraging nurses to pursue nursing innovation to improve health care quality and increase nursing productivity by proposing innovative training methods, products, services, care skills, and care methods. This study tried to explore the cross-level impact of market orientation on nursing innovation. In our study, 3 to 7 nurses and 1 manager were selected from each nursing team to act as respondents. The questionnaire survey began after the managers of each nursing team and the nurses had been anonymously coded and paired up in Taiwan in 2009-2010. A total of 808 valid questionnaires were collected, including 172 valid teams. Hierarchical linear modeling was used for the analysis. Nursing innovation is the sum of knowledge creation, innovation behavior, and innovation diffusion displayed by the nurses during nursing care. The level of knowledge creation, as perceived by the nurses, was the highest, whereas the level of innovation diffusion was the lowest. Results of hierarchical linear modeling showed that only competitor orientation yielded a significant positive influence on knowledge creation, innovation behavior, or innovation diffusion. The r values were 0.53, 0.49, and 0.61, respectively. Customer orientation and interfunctional coordination did not have significant effects on nursing innovation. Hospital nurses exhibited better performance in knowledge creation than in innovation behavior and diffusion. Only competitor orientation had a significantly positive and cross-level influence on nursing innovation. However, competitor orientation was observed to be the lowest dimension of market orientation, which indicates that this factor should be the focus when improving nursing innovations in the future. Therefore, managers should continually understand the strategies, advantages, and methods of their competitors.

  20. Elastic tunneling identification through crossings, anti-crossings and splitting of states in the complex electronic current of systems based on mesoscopic molecules

    Science.gov (United States)

    López, Luis I. A.; Mendoza, Michel; Ujevic, Sebastian

    2013-09-01

    We have systematically studied the conductance σ( E,B) and the electronic current line shapes J( V ex ) through complex mesoscopic molecules in an elastic resonant tunneling regime. The studied systems are based on GaAs/AlGaAs hetero-structures, with several discrete states in each coupled mesoscopic molecule. The molecules were formed using different wells and barrier widths. These systems allow effective couplings and uncouplings that lead to elastic processes as a function of the electronic potential V ex and magnetic field B. In this situation, the J( V ex ) and σ( E, B) curves exhibit a sequence of peaks of difficult interpretation, in which crossings and anti-crossings (a splitting if it is generated in the resonance condition) of states contribute in a way that they cannot be easily identified. Performing a systematic analysis of the evolution of these states (before the resonance condition), we were able to determine the origin of these current peaks. We have found that the coupling of states (anti-crossing) around the resonance region can be identified as a broad mirrored- D line shape in the J( V ex ) curves. The mirrored- D line shape peaks can be clearly differentiated from the neighboring peaks because the last ones follow a very defined increasing sequence in their intensities and widths. Also, this behavior (fingerprint) can be used to identify possible splitting of states in the J( V ex ). The splittings that are generated between states with different quantum numbers (quantum numbers associated to the individual well) follow an unexpected opposite behavior when compared with those generated between states with the same quantum numbers (quasi-miniband). All these results are also observed in the conductance σ( E, B) associated with complex mesoscopic molecules based on a two-dimensional electron gas.

  1. Serum vitamin d levels and the components of metabolic syndrome: an analytical cross-sectional study

    International Nuclear Information System (INIS)

    Roomi, M.A.; Farooq, A.; Ullah, E.; Lone, K.P.

    2015-01-01

    The present study was planned to determine the serum vitamin D levels and its relation with the various components of metabolic syndrome (MetS) in MetS positive and MetS negative subjects. Methods: This analytical cross-sectional study on 88 subjects who were divided into two groups based on whether they fulfill the diagnostic criteria for MetS or not. Fasting serum glucose, lipid profile, insulin, HOMA-IR and vitamin D levels were measured. Two sample-t test and Mann-Whitney U tests were used to compare the differences. Pearson and Spearman correlation tests were used to observe the correlations. Results: BMI (p=0.001), waist/hip ratio (p=0.001), systolic blood pressure (p=0.010), diastolic blood pressure (p=0.010), fasting serum TGs (p = 0.001), TG/HDL ratio (p=0.001), fasting blood sugar (p=0.010), fasting serum insulin (p = 0.001) and HOMA-IR (p=0.001) were significantly high in MetS positive than MetS negative subjects. In MetS Positive subjects, serum vitamin D levels were found to have negative correlation with serum LDL (r= -0.485, p=0.001), total cholesterol (r= -0.408, p=0.007) and total cholesterol/HDL ratio (r= -0.355, p=0.019). Moreover, serum vitamin D levels were found to have positive correlation with HDL/LDL ratio (r= 0.443, p=0.003). Other components of MetS did not show significant correlation with serum vitamin D levels in MetS positive subjects. In MetS negative subjects, serum vitamin D levels did not show any significant correlation with any of the study parameters. Conclusions: Serum vitamin D levels were correlated with a number of MetS components which may be controlled by optimizing vitamin D levels. (author)

  2. Research Update: Spatially resolved mapping of electronic structure on atomic level by multivariate statistical analysis

    International Nuclear Information System (INIS)

    Belianinov, Alex; Ganesh, Panchapakesan; Lin, Wenzhi; Jesse, Stephen; Pan, Minghu; Kalinin, Sergei V.; Sales, Brian C.; Sefat, Athena S.

    2014-01-01

    Atomic level spatial variability of electronic structure in Fe-based superconductor FeTe 0.55 Se 0.45 (T c = 15 K) is explored using current-imaging tunneling-spectroscopy. Multivariate statistical analysis of the data differentiates regions of dissimilar electronic behavior that can be identified with the segregation of chalcogen atoms, as well as boundaries between terminations and near neighbor interactions. Subsequent clustering analysis allows identification of the spatial localization of these dissimilar regions. Similar statistical analysis of modeled calculated density of states of chemically inhomogeneous FeTe 1−x Se x structures further confirms that the two types of chalcogens, i.e., Te and Se, can be identified by their electronic signature and differentiated by their local chemical environment. This approach allows detailed chemical discrimination of the scanning tunneling microscopy data including separation of atomic identities, proximity, and local configuration effects and can be universally applicable to chemically and electronically inhomogeneous surfaces

  3. Radiation levels at CERN's injectors and their impact on electronic equipment

    CERN Document Server

    AUTHOR|(SzGeCERN)649218; Brugger, Markus

    2013-01-01

    Electronic devices operating in hostile radiation environments, such as those found close to high-energy particle accelerators, can suffer from different types of radiation induced failures. At CERN, the mixed particle and energy radiation fields present at the Large Hadron Collider (LHC) and its injector chain can give rise to both stochastic and cumulative effects causing radiation induced failures of exposed electronics and materials, thus directly impacting components and system lifetimes, as well as maintenance requirements. With its original focus on the LHC, the Radiation to Electronics (R2E) project has been successfully implementing mitigation actions in order to avoid accelerator downtime due to radiation induced failures on active electronics. In a next step, the emphasis is put on CERN's injector chain, collecting the respective available information about radiation levels, the definition of additional monitoring requirements and a critical analysis of present and future equipment installations. T...

  4. Double ionization of the hydrogen sulfide molecule by electron impact: Influence of the target orientation on multiple differential cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Imadouchene, N. [Laboratoire de Mécanique, Structures et Energétique Université Mouloud Mammeri de Tizi-Ouzou, B.P. 17, Tizi-Ouzou 15000 (Algeria); Aouchiche, H., E-mail: h_aouchiche@yahoo.fr [Laboratoire de Mécanique, Structures et Energétique Université Mouloud Mammeri de Tizi-Ouzou, B.P. 17, Tizi-Ouzou 15000 (Algeria); Champion, C. [Centre d’Etudes Nucléaires de Bordeaux Gradignan, Université Bordeaux, CNRS/IN2P3, Boîte Postale 120, Gradignan 33175 (France)

    2016-07-15

    Highlights: • The double ionization of the H{sub 2}S molecule is here theoretically studied. • The orientation dependence of the differential cross sections is scrutinized. • The specific double ionizing mechanisms are clearly identified. - Abstract: Multiple differential cross sections of double ionization of hydrogen sulfide molecule impacted by electrons are here investigated within the first Born approximation. In the initial state, the incident electron is represented by a plane wave function whereas the target is described by means of a single-center molecular wave function. In the final state, the two ejected electrons are described by Coulomb wave functions coupled by the Gamow factor, whereas the scattered electron is described by a plane wave. In this work, we analyze the role played by the molecular target orientation in the double ionization of the four outermost orbitals, namely 2b{sub 1}, 5a{sub 1}, 2b{sub 2} and 4a{sub 1} in considering the particular case of two electrons ejected from the same orbital. The contribution of each final state to the double ionization process is studied in terms of shape and magnitude for specific molecular orientations and for each molecular orbital we identified the mechanisms involved in the double ionization process, namely, the Shake-Off and the Two-Step 1.

  5. Effective and absolute cross sections for low-energy (1-30 eV) electron interactions with condensed biomolecules

    Science.gov (United States)

    Zheng, Yi; Sanche, Léon

    2018-06-01

    Ionizing radiation is intensively used for therapeutic [e.g., radiotherapy, brachytherapy, and targeted radionuclide therapy (TRT)], as well as for diagnostic medical imaging purposes. In these applications, the radiation dose given to the patient should be known and controlled. In conventional cancer treatments, absorbed dose calculations rely essentially on scattering cross sections (CSs) of the primary high-energy radiation. In more sophisticated treatments, such as combined radio- and chemo-therapy, a description of the details of energy deposits at the micro- and nano-scopic level is preferred to relate dose to radiobiological effectiveness or to evaluate doses at the biomolecular level, when radiopharmaceuticals emitting short-range radiation are delivered to critical molecular components of cancer cells (e.g., TRT). These highly radiotoxic compounds emit large densities of low-energy electrons (LEEs). More generally, LEE (0-30 eV) are emitted in large numbers by any type of high-energy radiation; i.e., about 30 000 per MeV of deposited primary energy. Thus, to optimize the effectiveness of several types of radiation treatments, the energy deposited by LEEs must be known at the level of the cell, nucleus, chromosome, or DNA. Such local doses can be evaluated by Monte Carlo (MC) calculations, which account event-by-event, for the slowing down of all generations of particles. In particular, these codes require as input parameters absolute LEE CSs for elastic scattering, energy losses, and direct damage to vital cellular molecules, particularly DNA, the main target of radiation therapy. In the last decade, such CSs have emerged in the literature. Furthermore, a method was developed to transform relative yields of damages into absolute CSs by measuring specific parameters in the experiments. In this review article, we first present a general description of dose calculations in biological media via MC simulation and give an overview of the CSs available from

  6. Cross section of W and Z inclusive production and the W/Z cross section ratio in association with one jet for the boson decaying into electron(s) with ATLAS 7 TeV data

    CERN Document Server

    Berglund, Elina

    2011-01-01

    This thesis investigates the inclusive production cross section of W and Z bosons as well as their ratio in association with one jet. The cross sections are estimated with 7 TeV LHC proton-proton collision data, collected by ATLAS during 2010, resulting in an integrated luminosity of approximately 40 pb−1 . This thesis focuses on the analysis performed in the electron channel, while comparisons with the results obtained in the muon channel also are included. This is the first time the W and Z production cross sections are measured at this center-of-mass energy and the results are important for various reasons, such as testing perturbative theoretical calculations and understanding these signatures as backgrounds to other physics processes. The final inclusive cross section values obtained in the electron channel are the following: σ(W → eν ) = 10.255 ± 0.031(stat) ± 0.190(syst) ± 0.349(lumi) ± 0.156(acc) nb σ(Z → ee) = 0.952 ± 0.010(stat) ± 0.026(syst) ± 0.032(lumi) ± 0.019(acc) nb The res...

  7. Subshell differential cross sections for electron transfer in collisions of U{sup 90+} ions with gaseous targets

    Energy Technology Data Exchange (ETDEWEB)

    Ma, X. [Institute of Modern Physics, Lanzhou, GS (China); Stoehlker, T.; Bosch, F.; Brinzanescu, O.; Kozhuharov, C.; Mokler, P. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Fritzsche, S. [Kassel Univ. (Gesamthochschule) (Germany); Ludziejewski, T. [Institute of Nuclear Physics, Swierk (Poland); Warczak, A. [Uniwersytet Jagiellonski, Cracow (Poland). Inst. Fizyki

    2000-10-01

    Balmer spectra produced in collisions between He-like uranium projectiles and gaseous targets (N{sub 2}, Ar, Kr, and Xe) were measured at the jet-target area of the ESR storage ring. The X-ray radiation were recorded in coincidence with the down charged projectiles having captured one electron from the target atom. By means of spectra simulation, all the significant Balmer transition lines were identified. Further on, the j-differential cross sections for electron capture into projectile subshells were deduced from the well resolved spectra. For the heavier targets, where NRC contributes considerably, systematic deviations between experiment and the continuum distorted wave approximation are observed. (orig.)

  8. Neutron cross section measurement using the Oak Ridge Electron Linear Accelerator

    International Nuclear Information System (INIS)

    Winters, R.R.

    1991-08-01

    This report discusses: argon-40 -- neutron reaction total cross sections from 6.9 kev to 50 kev; The maxwellian averaged neutron capture cross section of oxygen-16; r-matrix parameter analysis of the lead-208 -- neutron reaction cross section measurement; r-matrix parameter analysis of the ORELA neutron transmission zirconium-90 low energy measurement; porting computer codes from the HP9000 to the IBM RISC/6000;and measurements of neutron reactions with strontium-88, zirconium-90, and calcium-40

  9. Polybrominated diphenyl ethers--plasma levels and thyroid status of workers at an electronic recycling facility.

    Science.gov (United States)

    Julander, A; Karlsson, M; Hagström, K; Ohlson, C G; Engwall, M; Bryngelsson, I-L; Westberg, H; van Bavel, B

    2005-08-01

    Personnel working with electronic dismantling are exposed to polybrominated diphenyl ethers (PBDEs), which in animal studies have been shown to alter thyroid homeostasis. The aim of this longitudinal study was to measure plasma level of PBDEs in workers at an electronic recycling facility and to relate these to the workers' thyroid status. PBDEs and three thyroid hormones: triiodothyronine (T(3)), thyroxin (T(4)) and thyroid stimulating hormone (TSH) were repeatedly analysed in plasma from 11 workers during a period of 1.5 years. Plasma levels of PBDEs at start of employment were plasma levels of PBDEs fluctuated during the study period. Due to small changes in thyroid hormone levels it was concluded that no relevant changes were present in relation to PBDE exposure within the workers participating in this study.

  10. Cross sections for one-electron capture by highly stripped ions of Be, B and C from H2 and Ar below 10 keV

    International Nuclear Information System (INIS)

    Takagi, S.; Ohtani, S.; Kadota, K.; Fujita, J.

    1982-03-01

    Cross sections for one-electron capture by highly stripped ions of Be, B and C from H 2 and Ar are measured at low energies below 10 keV. The cross sections are nearly independent of the collision energy investigated. The distinct oscillation with incident ionic charge g in the cross sections are observed. (author)

  11. Correlation electron cyclotron emission diagnostic and improved calculation of turbulent temperature fluctuation levels on ASDEX Upgrade

    Science.gov (United States)

    Creely, A. J.; Freethy, S. J.; Burke, W. M.; Conway, G. D.; Leccacorvi, R.; Parkin, W. C.; Terry, D. R.; White, A. E.

    2018-05-01

    A newly upgraded correlation electron cyclotron emission (CECE) diagnostic has been installed on the ASDEX Upgrade tokamak and has begun to perform experimental measurements of electron temperature fluctuations. CECE diagnostics measure small amplitude electron temperature fluctuations by correlating closely spaced heterodyne radiometer channels. This upgrade expanded the system from six channels to thirty, allowing simultaneous measurement of fluctuation level radial profiles without repeat discharges, as well as opening up the possibility of measuring radial turbulent correlation lengths. Newly refined statistical techniques have been developed in order to accurately analyze the fluctuation data collected from the CECE system. This paper presents the hardware upgrades for this system and the analysis techniques used to interpret the raw data, as well as measurements of fluctuation spectra and fluctuation level radial profiles.

  12. Approaching an organic semimetal: Electron pockets at the Fermi level for a p-benzoquinonemonoimine zwitterion

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, Luis G.; Velev, Julian [Department of Physics and Electronics, University of Puerto Rico, Humacao (United States); Institute for Functional Nanomaterials, University of Puerto Rico, San Juan (United States); Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, NE (United States); Zhang, Zhengzheng [Department of Physics, University of Puerto Rico, Rio Piedras, San Juan (United States); Alvira, Jose; Vega, Omar; Diaz, Gerson [Department of Physics and Electronics, University of Puerto Rico, Humacao (United States); Routaboul, Lucie; Braunstein, Pierre [Laboratoire de Chimie de Coordination, Institut de Chimie (UMR 7177 CNRS), Universite de Strasbourg (France); Doudin, Bernard [Institut de Physique, Applique de Physique et Chimie des Materiaux de Strasbourg, Universite Louis Pasteur Strasbourg (France); Losovyj, Yaroslav B. [Institute for Functional Nanomaterials, University of Puerto Rico, San Juan (United States); J. Bennett Johnston Sr. Center for Advanced Microstructures and Devices, Louisiana State Univ., Baton Rouge, LA (United States); Dowben, Peter A. [Institute for Functional Nanomaterials, University of Puerto Rico, San Juan (United States)

    2012-08-15

    There is compelling evidence of electron pockets, at the Fermi level, in the band structure for an organic zwitterion molecule of the p-benzoquinonemonoimine type. The electronic structure of the zwitterion molecular film has a definite, although small, density of states evident at the Fermi level as well as a nonzero inner potential and thus is very different from a true insulator. In spite of a small Brillouin zone, significant band width is observed in the intermolecular band dispersion. The results demonstrate that Bloch's theorem applies to the wave vector dependence of the electronic band structure formed from the molecular orbitals of adjacent molecules in a molecular thin film of a p-benzoquinonemonoimine type zwitterion. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. The front-end (Level-0) electronics interface module for the LHCb RICH detectors

    Energy Technology Data Exchange (ETDEWEB)

    Adinolfi, M. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Bibby, J.H. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Brisbane, S. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Gibson, V. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Harnew, N. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Jones, M. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Libby, J. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom)]. E-mail: j.libby1@physics.ox.ac.uk; Powell, A. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Newby, C. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Rotolo, N. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Smale, N. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Somerville, L.; Sullivan, P.; Topp-Jorgensen, S. [Sub-department of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Wotton, S. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Wyllie, K. [CERN, CH-1211, Geneva 23 (Switzerland)

    2007-03-11

    The front-end (Level-0) electronics interface module for the LHCb Ring Imaging Cherenkov (RICH) detectors is described. This module integrates the novel hybrid photon detectors (HPDs), which instrument the RICH detectors, to the LHCb trigger, data acquisition (DAQ) and control systems. The system operates at 40 MHz with a first-level trigger rate of 1 MHz. The module design is presented and results are given for both laboratory and beam tests.

  14. The front-end (Level-0) electronics interface module for the LHCb RICH detectors

    International Nuclear Information System (INIS)

    Adinolfi, M.; Bibby, J.H.; Brisbane, S.; Gibson, V.; Harnew, N.; Jones, M.; Libby, J.; Powell, A.; Newby, C.; Rotolo, N.; Smale, N.; Somerville, L.; Sullivan, P.; Topp-Jorgensen, S.; Wotton, S.; Wyllie, K.

    2007-01-01

    The front-end (Level-0) electronics interface module for the LHCb Ring Imaging Cherenkov (RICH) detectors is described. This module integrates the novel hybrid photon detectors (HPDs), which instrument the RICH detectors, to the LHCb trigger, data acquisition (DAQ) and control systems. The system operates at 40 MHz with a first-level trigger rate of 1 MHz. The module design is presented and results are given for both laboratory and beam tests

  15. Photovoltaic Shading Testbed for Module-Level Power Electronics: 2016 Performance Data Update

    Energy Technology Data Exchange (ETDEWEB)

    Deline, Chris [National Renewable Energy Lab. (NREL), Golden, CO (United States); Meydbray, Jenya [PV Evolution Labs (PVEL), Davis, CA (United States); Donovan, Matt [PV Evolution Labs (PVEL), Davis, CA (United States)

    2016-09-01

    The 2012 NREL report 'Photovoltaic Shading Testbed for Module-Level Power Electronics' provides a standard methodology for estimating the performance benefit of distributed power electronics under partial shading conditions. Since the release of the report, experiments have been conducted for a number of products and for different system configurations. Drawing from these experiences, updates to the test and analysis methods are recommended. Proposed changes in data processing have the benefit of reducing the sensitivity to measurement errors and weather variability, as well as bringing the updated performance score in line with measured and simulated values of the shade recovery benefit of distributed PV power electronics. Also, due to the emergence of new technologies including sub-module embedded power electronics, the shading method has been extended to include power electronics that operate at a finer granularity than the module level. An update to the method is proposed to account for these emerging technologies that respond to shading differently than module-level devices. The partial shading test remains a repeatable test procedure that attempts to simulate shading situations as would be experienced by typical residential or commercial rooftop photovoltaic (PV) systems. Performance data for multiple products tested using this method are discussed, based on equipment from Enphase, Solar Edge, Maxim Integrated and SMA. In general, the annual recovery of shading losses from the module-level electronics evaluated is 25-35%, with the major difference between different trials being related to the number of parallel strings in the test installation rather than differences between the equipment tested. Appendix D data has been added in this update.

  16. A new time of flight mass spectrometer for absolute dissociative electron attachment cross-section measurements in gas phase

    Science.gov (United States)

    Chakraborty, Dipayan; Nag, Pamir; Nandi, Dhananjay

    2018-02-01

    A new time of flight mass spectrometer (TOFMS) has been developed to study the absolute dissociative electron attachment (DEA) cross section using a relative flow technique of a wide variety of molecules in gas phase, ranging from simple diatomic to complex biomolecules. Unlike the Wiley-McLaren type TOFMS, here the total ion collection condition has been achieved without compromising the mass resolution by introducing a field free drift region after the lensing arrangement. The field free interaction region is provided for low energy electron molecule collision studies. The spectrometer can be used to study a wide range of masses (H- ion to few hundreds atomic mass unit). The mass resolution capability of the spectrometer has been checked experimentally by measuring the mass spectra of fragment anions arising from DEA to methanol. Overall performance of the spectrometer has been tested by measuring the absolute DEA cross section of the ground state SO2 molecule, and the results are satisfactory.

  17. Electron impact single detachment on the F- ions using the heavy ion storage ring CRYRING: cross-section determination

    International Nuclear Information System (INIS)

    Andersson, K.; Hanstorp, D.; Oesterdahl, F.; Danared, H.; Kaellberg, A.

    2001-01-01

    Electron Impact Single Detachment (EISD) of F - has been studied using the heavy ion storage ring CRYRING at the Manne Siegbahn Laboratory, Stockholm, Sweden. F - ions stored in the ring were merged with an electron beam in one of the ring sections. Neutral F atoms produced in the EISD process were detected in the zero-degree direction using a surface barrier detector. The threshold for the detachment process was found to be around 7.6 eV, thus more than twice the binding energy of F - . The cross-sections increased smoothly up to 55 eV where it reached a maximum of 1.9 x 10 -16 cm 2 . At higher energies a slow decrease of the cross-section was observed, which follows the energy dependence predicted by the Bethe-Born approximation. The experiment showed that CRYRING can be used favourably for studies of anions, and several experiments are forthcoming. (orig.)

  18. An X-Ray of the Level of Electronic Purse Usage in Nigeria | Ogbuji ...

    African Journals Online (AJOL)

    This study sets out to examine the level of e-purse usage in Nigeria. Despite the invasion of e-purse as electronic banking channels that has the potential of disempowering the cash systems of exchange and granting firms competitive edge, it is interesting to note that the rate of cash usage still dominates in the Nigeria ...

  19. Building America Case Study: Photovoltaic Systems with Module-Level Power Electronics

    Energy Technology Data Exchange (ETDEWEB)

    2015-09-01

    Direct current (DC) power optimizers and microinverters (together known as module-level power electronics, or MLPE) are one of the fastest growing market segments in the solar industry. According to GTM Research in The Global PV Inverter Landscape 2015, over 55% of all residential photovoltaic (PV) installations in the United States used some form of MLPE in 2014.

  20. Determinants of maternal and umbilical blood lead levels: a cross-sectional study, Mosul, Iraq

    Directory of Open Access Journals (Sweden)

    Al-Jomard Raghad A

    2009-03-01

    Full Text Available Abstract Background The populations who are most sensitive to lead exposure from various sources are pregnant women and their newborns. Aiming to explore the presence of correlation between maternal and cord blood lead levels and to identify potential predictors that may influence both levels, the present study has been conducted. Methods A cross-sectional study was conducted covering 350 full terms maternal-newborns pairs from Mosul maternity hospitals. Data were obtained directly from women just before delivery by the use of a detailed questionnaire form. Maternal and umbilical blood lead levels were estimated using LEADCARE® Blood Lead Testing System and Kits. Results A positive significant correlation was found between maternal and cord blood lead values (r = 0.856, p = 0.001. By backward stepwise logistic regression analysis the followings emerged as significant potential predictors of high maternal blood lead: low parity, smoking and Hb level Conclusion Study results have provided baseline data needed to be transformed to decision makers to implement measures to eliminate lead from the environment and protect future generation from its deleterious effects.

  1. The tension adjuster used at the work line of electron beam radiation cross-linking wire and cable

    International Nuclear Information System (INIS)

    Zhang Yingfa; Liu Zhenhao; Yin Xuejun

    1999-01-01

    The tension adjuster is an important equipment in the transport system at the work line of electron beam radiation cross-linking wire and cable to realize the velocity synchronism. There are many kinds of the adjuster. By putting various adjusters together properly, the authors can keep the line work stable and raise the quality of the product. Two kinds of standing adjuster and their mechanism are introduced. Also the corresponding figures and formulas are shown

  2. Associations of attitudes towards electronic cigarettes with advertisement exposure and social determinants: a cross sectional study.

    Science.gov (United States)

    Reinhold, Benjamin; Fischbein, Rebecca; Bhamidipalli, Surya Sruthi; Bryant, Jennifer; Kenne, Deric R

    2017-01-01

    The exposure of young adults to electronic cigarette (e-cigarette) advertisements has risen rapidly. E-cigarette ads have been shown to increase short term perceived acceptability of using e-cigarettes in places where traditional cigarettes are banned. We set out to investigate if advertising exposure was related to perceptions of harm, addictiveness, and acceptability of use of e-cigarettes in places where traditional cigarettes are banned. Using a cross-sectional design, 6037 students at a large Midwestern university between the ages of 18-24 were surveyed about e-cigarette use and smoking status. Bivariate analyses were performed associating perception of harm, addictiveness, and acceptability of e-cigarette use in places where smoking is banned with demographic and other background factors, and e-cigarette advertising exposure through different media channels. Logistic regression analyses were used to explore the relationship of these factors on perceptions of harm, addictiveness and acceptability of e-cigarette use in places where smoking is banned. More than a quarter (27.4%) of respondents had used an e-cigarette, greater than half (53.2%) had seen an advertisement on TV and 42.0% had seen an advertisement on the Internet. Logistic regressions revealed that being white, male, an e-cigarette user, a smoker, having a mother who smoked, and Internet advertisement exposure were associated with lower perceived harm of e-cigarettes. The same factors, plus having seen advertisements on TV, were associated with increased likelihood of perceiving e-cigarette use in bars, stores, at work and in a dorm as acceptable. Perceiving use of e-cigarettes as acceptable in classrooms was also associated with the aforementioned factors and also included race. Only being male and an e-cigarette user were associated with lower perceived addictiveness of e-cigarettes. E-cigarette use is increasing in adolescents and young adults, as is exposure to e-cigarette advertising

  3. Differing Levels of Forestry Best Management Practices at Stream Crossing Structures Affect Sediment Delivery and Installation Costs

    Directory of Open Access Journals (Sweden)

    Brian C. Morris

    2016-03-01

    Full Text Available Forestry best management practices (BMPs are used to reduce sedimentation from forest stream crossings. Three BMP treatments (BMP−, BMP-std, and BMP+ were applied to three forest road stream crossings (bridge, culvert, and ford. BMP− did not meet existing BMP guidelines, BMP-std met standard recommendations, and BMP+ treatments exceeded recommendations. Following BMP applications, three simulated rainfall intensities (low, medium, and high were applied in order to evaluate sediment delivery from crossing type and BMP level. During rainfall simulation, sediment concentrations (mg/L were collected with automated samplers and discharge (L/s was estimated to calculate total sediment loading. Costs of stream crossings and BMP levels were also quantified. Mean sediment associated with the three stream crossings were 3.38, 1.87, and 0.64 Mg for the BMP−, BMP-std, and BMP+ levels, respectively. Ford, culvert, and bridge crossings produced 13.04, 12.95, and 0.17 Mg of sediment during construction, respectively. BMP enhancement was more critical for sediment control at the culvert and ford crossings than at the bridge. Respective costs for BMP−, BMP-std, and BMP+ levels were $5,368, $5,658, and $5,858 for the bridge; $3,568, $4,166 and $4,595 for the culvert; and $180, $420 and $1,903 for the ford. Costs and sediment values suggest that current standard BMP levels effectively reduce stream sediment while minimizing costs.

  4. Newly calculated absolute cross-section for the electron-impact ionization of C2H2+

    International Nuclear Information System (INIS)

    Deutsch, H.; Becker, K.; Defrance, P.; Probst, M.; Mark, T.D.; Limtrakul, J.

    2006-01-01

    New measurements of the cross-section for electron impact ionization of the molecular ion C 2 H 2 + have been carried out recently. These data differ significantly from earlier data, because cross-sections corresponding to all the possible dissociative ionization processes were determined. The new data in conjunction with the significant discrepancies between the earlier data and the results of various calculations, which disagreed among themselves by a factor of 3, motivated a renewed attempt to apply the semi-classical Deutsch-Mark (DM) formalism to the calculation of the absolute electron-impact ionization cross-section of this molecular ion. A quantum chemical molecular orbital population analysis for both the neutral molecule and the ion revealed that in the case of C 2 H 2 + the singly occupied molecular orbital (i.e. the 'missing' electron) is highly localized near the site of a C atom in the molecule. This information is explicitly incorporated in our formalism. The results obtained by taking the ionic character directly into account are in excellent agreement with the recent experimental data. (authors)

  5. Comparison of Aqueous Humor Nitric Oxide Levels After Different Corneal Collagen Cross-Linking Methods.

    Science.gov (United States)

    Yuksel, Nilay; Ozel-Turkcu, Ummuhani; Yalinbas, Duygu; Novruzlu, Sahin; Bilgihan, Ayse; Bilgihan, Kamil

    2016-12-01

    Nitric oxide production can cause either apoptotic or necrotic cell death through oxidative stress. We aimed to investigate the nitrite oxide metabolites (NO x ) and nitrite levels in the aqueous humor of rabbit eyes after different methods of corneal collagen cross-linking (CXL). Twenty-four eyes of 12 adult New Zealand rabbits were used. They were assigned into four groups, each including six eyes. Group 1 (control) consisted of eyes with no treatment. Group 2 received UV-A power setting at 3 mW/cm 2 for 30 minutes of continuous exposure and named as standard CXL group. Group 3 received UV-A power setting at 30 mW/cm 2 for 3 minutes of continuous exposure and named as accelerated CXL (A-CXL) group. Group 4 received UV-A power setting at 30 mW/cm 2 for 6 minutes of pulsed exposure (1 sec on, 1 sec off) and named as pulse-light accelerated CXL (PLA-CXL). Aqueous humors were aspirated from anterior chamber with a 27G needle after 1 hour UV-A exposure. NO x and nitrite levels were measured Results: The nitrite levels in aqueous humor were significantly increased in Group 2 and Group 3 when compared with Group 1 (p = 0.000, p = 0.036, respectively). When treatment modalities were compared with each other, high nitrite level in Group 2 was statistically significant when compared with Group 4 (p = 0.019). NO x levels were higher in Group 2 when compared with Group 1 (p = 0.006). Numerous studies investigated the physiological and pathophysiological roles of NO. NO is considered one of the most important molecule for ocular health. According to NO x level in aqueous humor, it seems that PLA-CXL is the safest method due to the similar results with control group.

  6. Influence of Electron Molecule Resonant Vibrational Collisions over the Symmetric Mode and Direct Excitation-Dissociation Cross Sections of CO2 on the Electron Energy Distribution Function and Dissociation Mechanisms in Cold Pure CO2 Plasmas.

    Science.gov (United States)

    Pietanza, L D; Colonna, G; Laporta, V; Celiberto, R; D'Ammando, G; Laricchiuta, A; Capitelli, M

    2016-05-05

    A new set of electron-vibrational (e-V) processes linking the first 10 vibrational levels of the symmetric mode of CO2 is derived by using a decoupled vibrational model and inserted in the Boltzmann equation for the electron energy distribution function (eedf). The new eedf and dissociation rates are in satisfactory agreement with the corresponding ones obtained by using the e-V cross sections reported in the database of Hake and Phelps (H-P). Large differences are, on the contrary, found when the experimental dissociation cross sections of Cosby and Helm are inserted in the Boltzman equation. Comparison of the corresponding rates with those obtained by using the low-energy threshold energy, reported in the H-P database, shows differences up to orders of magnitude, which decrease with the increasing of the reduced electric field. In all cases, we show the importance of superelastic vibrational collisions in affecting eedf and dissociation rates either in the direct electron impact mechanism or in the pure vibrational mechanism.

  7. Direct observation of children's preferences and activity levels during interactive and online electronic games.

    Science.gov (United States)

    Sit, Cindy H P; Lam, Jessica W K; McKenzie, Thomas L

    2010-07-01

    Interactive electronic games have recently been popularized and are believed to help promote children's physical activity (PA). The purpose of the study was to examine preferences and PA levels during interactive and online electronic games among overweight and nonoverweight boys and girls. Using a modification of the SOFIT, we systematically observed 70 Hong Kong Chinese children (35 boys, 35 girls; 50 nonoverweight, 20 overweight), age 9 to 12 years, during 2 60-minute recreation sessions and recorded their game mode choices and PA levels. During Session One children could play either an interactive or an online electronic bowling game and during Session Two they could play an interactive or an online electronic running game. Children chose to play the games during 94% of session time and split this time between interactive (52%) and online (48%) versions. They engaged in significantly more moderate-to-vigorous physical activity (MVPA) during interactive games than their online electronic versions (70% vs. 2% of game time). Boys and nonoverweight children expended relatively more energy during the interactive games than girls and overweight children, respectively. New-generation interactive games can facilitate physical activity in children, and given the opportunity children may select them over sedentary versions.

  8. SLP - A single level Breit-Wigner cross-section generating programme

    International Nuclear Information System (INIS)

    Doherty, G.

    1965-06-01

    Unbroadened cross-sections are calculated from a single level Breit-Wigner approximation which allows for resonance-potential interference but not resonance-resonance interference. Doppler broadening, and instrumental resolution broadening for thin samples, are optionally performed by successive numerical convolutions. An energy point selection and discard system enables the cross-section over a specified energy range to be represented to a required degree of accuracy using the minimum number of energy points. An energy grid prepared by the user can be incorporated in the calculation but the programme will usually be more efficient if only the end points of the energy range of interest are specified by the user and the intermediate energy points left to the programme to organise. The capacity of the programme varies with the energy range and type of resonance (narrow or broad). About fifty resonances may be sufficient to generate an energy grid of 4000 energy points, which is the maximum allowable energy vector. The programme is written in KDF9 EGTRAN (a FORTRAN dialect); output is printed and may be copied on cards, and intermediate results are stored on magnetic disc. (author)

  9. Cross-sections of charge and electronic states change of particles at ion-ion and ion-molecule collisions

    International Nuclear Information System (INIS)

    Panov, M.N.; Afrosimov, V.V.; Basalaev, A.A.; Guschina, N.A.; Nikulin, V.K.

    2006-01-01

    The interactions of protons and alpha-particles with hydrocarbons are investigated. A quantum-mechanical computation of the electronic structure of all hydrocarbons from methane to butane and its fragment ions was performed in the Hartree-Fock RHF/UHF approximation using a GAMESS program (General Atomic Molecular Electron Structure System). The correlation energy was taken into account within the framework of MP2 perturbation theory. The structural parameters of the hydrocarbon molecules and their charged and neutral fragments were calculated in two cases: in the geometry of the parent molecule or of the relaxation states. The difference of the full energy of the same fragments in and out of brackets gives us the vibration excitation energies of the fragments at the moment of creation. Additional Mulliken effective charges (in electron charge units) of atoms in the fragments have been calculated. The calculations show that removing one electron from the ethane molecule without electronic excitation produced a single charged molecular ion in vibration state with binding energy of hydrogen atoms, some decimal eV. As results we obtain C 2 H 6 + and C 2 H 5 + . Additional fragmentation of hydrocarbon needs electronic excitation of produced single charged ions. Cross sections for electron capture and excitation processes in collisions between the hydrogen-like He + , B 4+ and O 7+ ions have been evaluated. The purpose of the theory within this project during the period under review was to get for the first time new data on Single-Electron Capture (SEC) and Excitation Processes (EP) in collisions of He + (1s) ions with hydrogen-like impurity ions B 4+ (1s) and O 7+ (1s) in the energy range for He + ions from 0.2 MeV to 3.0 MeV. The calculations were carried out by using the method of close-coupling equations with basis sets of eleven and ten quasimolecular two-electron states for reactions (1, 2) and (3, 4), respectively (entrance channel, seven charge transfer channels

  10. Microscopic description of dissipative dynamics of a level-crossing transition

    Energy Technology Data Exchange (ETDEWEB)

    Scala, M.; Militello, B.; Messina, A. [Dipartimento di Fisica dell' Universita di Palermo, Via Archirafi 36, I-90123 Palermo (Italy); Vitanov, N. V. [Department of Physics, Sofia University, 5 James Bourchier Boulevard, BG-1164 Sofia (Bulgaria)

    2011-08-15

    We analyze the effect of a dissipative bosonic environment on the Landau-Zener-Stueckelberg-Majorana (LZSM) level crossing model by using a microscopic approach to derive the relevant master equation. For an environment at zero temperature and weak dissipation, our microscopic approach confirms the independence of the survival probability on the decay rate that has been predicted earlier by the simple phenomenological LZSM model. For strong decay the microscopic approach predicts a notable increase of the survival probability, which signals dynamical decoupling of the initial state. Unlike the phenomenological model, our approach makes it possible to study the dependence of the system dynamics on the temperature of the environment. In the limit of very high temperature we find that the dynamics is characterized by a very strong dynamical decoupling of the initial state--the temperature-induced quantum Zeno effect.

  11. Industry growth, work role characteristics, and job satisfaction: a cross-level mediation model.

    Science.gov (United States)

    Ford, Michael T; Wooldridge, Jessica D

    2012-10-01

    The associations between industry revenue growth, individual work role characteristics, and job satisfaction were examined in this cross-level mediation analysis. Work roles were expected to be more autonomous, involve greater skill variety, and offer more opportunities for growth and development for workers in growing industries than for workers in declining industries. Supervisor support was also hypothesized to be stronger for workers in high-growth industries. Results from a nationally representative (U.S.) sample of service industry workers, using multilevel modeling, supported these propositions and suggest that job enrichment mediates relations between industry growth and job satisfaction. Associations between industry growth and autonomy were also stronger among workers in occupations that are less normatively autonomous, suggesting that industry growth fosters a weakening, and industry decline a strengthening, of traditional differences in autonomy across work roles. These results contribute to a multilevel perspective on organizational environments, individual work roles, and worker attitudes and well-being.

  12. Electron transfer and redox metalloenzyme catalysis at the single-molecule level

    DEFF Research Database (Denmark)

    Hansen, Allan Glargaard; Zhang, Jingdong; Christensen, Hans Erik Mølager

    2004-01-01

    transfer (ET). Image interpretation requires, however, theoretical support, as STM represents both electronic and topographic features. Molecules with accessible redox levels offer other insight into electron tunneling mechanisms, addressed in detail for ET metalloproteins. We present here in situ STM...... of the blue redox metalloenzyme copper nitrite reductase (Achromobacter xylosoxidans, AxCuNiR) on Au(111) electrode surfaces modified by a self-assembled cysteamine monolayer. AxCuNiR displays strong nitrite reduction waves in this environment. AxCuNiR/cysteamine/ Au(111) surfaces were imaged at KNO2...

  13. Physiological and anthropometric characteristics of top-level youth cross-country cyclists.

    Science.gov (United States)

    Fornasiero, Alessandro; Savoldelli, Aldo; Modena, Roberto; Boccia, Gennaro; Pellegrini, Barbara; Schena, Federico

    2018-04-01

    In the literature there is a lack of data about the development of top level athletes in cross-country mountain biking (XCO). The purpose of this study was to analyze anthropometric and physiological characteristics of some of the best XCO bikers aged between 13 and 16. The study involved 45 bikers (26 males and 19 females) belonging to a youth national team. The evaluations, consisting of anthropometric measures, incremental cycling tests (VO 2max , PPO, P@RCP), and 30 s Wingate Tests (PMax, PMean), were conducted over a lapse of 4 years. Our findings showed in bikers, already at young age, a specific athletic profile advantageous for XCO performance. At the age of 16, just before entering the junior category and competing at international level, male and female bikers showed physiological values normalized to the body mass comparable to those reported in literature for high level athletes (VO 2max >70 and >60 ml/kg/min, PPO >6.5 and >5.5 W/kg, respectively in males and females). The production of high power-to-weight ratios and high peaks of anaerobic power attests the presence of highly developed aerobic and anaerobic systems in young XCO cyclists reflecting the high physiological demand of this sport.

  14. Protein Oxidation Levels After Different Corneal Collagen Cross-Linking Methods.

    Science.gov (United States)

    Turkcu, Ummuhani Ozel; Yuksel, Nilay; Novruzlu, Sahin; Yalinbas, Duygu; Bilgihan, Ayse; Bilgihan, Kamil

    2016-03-01

    To evaluate advanced oxidation protein products (AOPP) levels, superoxide dismutase (SOD) enzyme activity, and total sulfhydryl (TSH) levels in rabbit corneas after different corneal collagen cross-linking (CXL) methods. Eighteen eyes of 9 adult New Zealand rabbits were divided into 3 groups of 6 eyes. The standard CXL group was continuously exposed to UV-A at a power setting of 3 mW/cm for 30 minutes. The accelerated CXL (A-CXL) group was continuously exposed to UV-A at a power setting of 30 mW/cm for 3 minutes. The pulse light-accelerated CXL (PLA-CXL) group received UV-A at a power setting of 30 mW/cm for 6 minutes of pulsed exposure (1 second on, 1 second off). Corneas were obtained after 1 hour of UV-A exposure, and 360-degree keratotomy was performed. SOD enzyme activity, AOPP, and TSH levels were measured in the corneal tissues. Compared with the standard CXL and A-CXL groups (133.2 ± 8.5 and 140.2 ± 6.2 μmol/mg, respectively), AOPP levels were found to be significantly increased in the PLA-CXL group (230.7 ± 30.2 μmol/mg) (P = 0.005 and 0.009, respectively). SOD enzyme activities and TSH levels did not differ between the groups (P = 0.167 and 0.187, respectively). CXL creates covalent bonds between collagen fibers because of reactive oxygen species. This means that more oxygen concentration during the CXL method will produce more reactive oxygen species and, thereby, AOPP. This means that in which CXL method occurs in more oxygen concentration that will produce more reactive oxygen species and thereby AOPP. This study demonstrated that PLA-CXL results in more AOPP formation than did standard CXL and A-CXL.

  15. Calculation of the positronium formation differential cross section for collision of electron with anti-hydrogen atoms

    International Nuclear Information System (INIS)

    Ghanbari Adivi, E.; Kanjuri, F.; Bolorizadeh, M.

    2006-01-01

    The positronium formation differential cross sections in collision of the high-energy but non-relativistic electrons with anti-hydrogen atoms are calculated by using the three-body Faddeev-Watson-Lovelace formalism. In a second-order approximation, the inter-nuclear and nuclear-electronic partial amplitudes therein the Faddeev-Watson series are calculated, analytically, in the range of 0-180 degrees of the scattering angles. The presence of the T homas peak a t 45 d egree i s investigated. The results are discussed for 1 and 10 keV impact energies and for electron transition from anti-hydrogen ground state into the different states therein the K-, L- and M- shells of the positronium atoms.

  16. Ionization of liquid water by fast electron impact: multiple differential cross sections for the 1B1 orbital

    International Nuclear Information System (INIS)

    Fojon, O A; De Sanctis, M L; Stia, C R; Vuilleumier, R; Politis, M-F

    2011-01-01

    We present a theoretical study of single ionization of water molecules in liquid phase by impact of fast electrons in a coplanar geometry. Multiple differential cross sections are obtained through a first order model obtained within the framework of an independent electron approximation in which relaxation of the target is not taken into account. The wavefunctions for a single water molecule in the liquid phase are obtained through a Wannier orbital formalism and the ejected electron is described by means of Coulomb functions. We also present averaged calculations over all molecular orientations. A comparison with previous theoretical and experimental results, the latter corresponding to water in gaz phase, shows a good agreement. The main physical features of the reaction (such as binary and recoil peaks) present in measurements for vapor are also observed in the present theoretical predictions.

  17. Absolute emission cross sections for electron-impact excitation of Zn+(4p 2P) and (5s 2S) terms

    International Nuclear Information System (INIS)

    Rogers, W.T.; Dunn, G.H.; Olsen, J.O.; Reading, M.; Stefani, G.

    1982-01-01

    Absolute emission cross sections for electron-impact excitation of the 3d 10 4p 2 P and 3d 10 5s 2 S terms of Zn + have been measured from below threshold to about 790 eV 2 P and 390 eV 2 S using the crossed-charged-beams technique. Both transitions have the abrupt onset at threshold characteristic of positive-ion excitation. The 2 P cross section shows considerable structure in the interval from threshold to near 20 eV, above which it falls off smoothly. Agreement with five-state close-coupling theory is excellent below 100 eV when cascading is included in the theory. Above 100 eV, the data lie above the theory. The peak value of the 2 P cross section is 9.4 x 10 -16 cm 2 essentially at threshold, while the peak value of the 2 S cross section is about 0.47 x 10 -16 cm 2 . The net linear polarization of the 3d 10 4p 2 P emission was measured (unresolved from the 3d 10 4d 2 D→3d 10 4p 2 P cascading transition), and these data were used to correct the cross-section data for anisotropy of the emitted light. The effective lifetime of the 3d 9 4s 2 2 D/sub 3/2/ level was measured by observing exponential decay of the 589.6-nm photons resulting from its decay

  18. Electron Impact Excitation Cross Sections of Xenon for Optical Plasma Diagnostic

    National Research Council Canada - National Science Library

    Srivastava, Rajesh

    2007-01-01

    In this project the researcher had taken up the calculation of xenon apparent emission-excitation cross sections for emission lines that have diagnostic value in the analysis of Xe-propelled electric thruster plasmas...

  19. Electron-impact rotationally elastic total cross sections for H2CO and HCOOH over a wide range of incident energy (0.01-2000 eV)

    International Nuclear Information System (INIS)

    Vinodkumar, Minaxi; Bhutadia, Harshad; Antony, Bobby; Mason, Nigel

    2011-01-01

    This paper reports computational results of the total cross sections for electron impact on H 2 CO and HCOOH over a wide range of electron impact energies from 0.01 eV to 2 keV. The total cross section is presented as sum of the elastic and electronic excitation cross sections for incident energies. The calculation uses two different methodologies, below the ionization threshold of the target the cross section is calculated using the UK molecular R-matrix code through the Quantemol-N software package while cross sections at higher energies are evaluated using the spherical complex optical potential formalism. The two methods are found to be consistent at the transition energy (∼15 eV). The present results are, in general, found to be in good agreement with previous experimental and theoretical results (wherever available) and, thus, the present results can serve as a benchmark for the cross section over a wide range of energy.

  20. Transport coefficients and cross sections for electrons in water vapour: Comparison of cross section sets using an improved Boltzmann equation solution

    Science.gov (United States)

    Ness, K. F.; Robson, R. E.; Brunger, M. J.; White, R. D.

    2012-01-01

    This paper revisits the issues surrounding computation of electron transport properties in water vapour as a function of E/n0 (the ratio of the applied electric field to the water vapour number density) up to 1200 Td. We solve the Boltzmann equation using an improved version of the code of Ness and Robson [Phys. Rev. A 38, 1446 (1988)], facilitating the calculation of transport coefficients to a considerably higher degree of accuracy. This allows a correspondingly more discriminating test of the various electron-water vapour cross section sets proposed by a number of authors, which has become an important issue as such sets are now being applied to study electron driven processes in atmospheric phenomena [P. Thorn, L. Campbell, and M. Brunger, PMC Physics B 2, 1 (2009)] and in modeling charged particle tracks in matter [A. Munoz, F. Blanco, G. Garcia, P. A. Thorn, M. J. Brunger, J. P. Sullivan, and S. J. Buckman, Int. J. Mass Spectrom. 277, 175 (2008)].

  1. Participation in the management of Greek Natura 2000 sites: evidence from a cross-level analysis.

    Science.gov (United States)

    Apostolopoulou, Evangelia; Drakou, Evangelia G; Pediaditi, Kalliope

    2012-12-30

    The governance of protected areas has experienced rapid advancement over the last two decades with regard to the inclusion of stakeholders and local communities into the management process. During the same period Greek biodiversity governance has been characterized by a shift, at least on paper, towards the adoption of participatory approaches primarily through the establishment of management agencies. However, this has not been institutionalized for the majority of Natura 2000 sites, thus posing questions on the existence, nature, and effectiveness of participation in sites with no management agency. This is the first conducted large scale, cross level participation analysis for Greek Natura 2000 sites enabling the formation of a representative picture of the situation in the country. We investigated the nature and role of participation in Greek biodiversity governance by exploring both general opinions regarding the national context of participation in Greek Natura 2000 network as well as site-specific opinions regarding three case study areas where Natura 2000 sites have been established. Overall, we analyzed the results of 96 interviews, conducted with national, regional and local level stakeholders and 734 questionnaires conducted with local communities of the three case study areas. Results indicate with non-significant difference among governance levels, or between case study sites, that stakeholders' participation exists mainly on paper whereas community participation is practically absent. Stakeholder engagement seems to take place through administrational documentation across levels and to be locally confined based mainly on personal contacts and initiatives. Interviewees and survey respondents indicated a preference towards improving stakeholders' participation and the community's engagement in the management of Natura 2000 sites. Overall, the results of this study revealed the urgent need for policy initiatives towards adopting meaningful, fair and

  2. Photoelectron and electron momentum spectroscopy of 1-butene at benchmark theoretical levels

    International Nuclear Information System (INIS)

    Shojaei, S H Reza; Morini, Filippo; Hajgató, Bálazs; Deleuze, Michael S

    2011-01-01

    The results of experimental studies of the valence electronic structure of 1-butene employing photoelectron spectroscopy as well as electron momentum spectroscopy are interpreted on the ground of quantitative calculations of one-electron and shake-up ionization energies and of the related Dyson orbitals, using one-particle Green's function theory in conjunction with the third-order algebraic diagrammatic construction scheme (ADC(3)). Comparison is made with simulations of (e, 2e) electron momentum distributions obtained from standard (B3LYP) Kohn-Sham orbitals. Our analysis is based on highly quantitative determinations of the energy difference between the cis and gauche (C 1 ) conformers, within ∼0.02 kcal mol -1 accuracy, and a thermostatistical evaluation thereby of conformer weights beyond the level of the rigid rotor harmonic oscillator approximation. Relative entropies are found to be particularly sensitive to hindered rotations. The shake-up onset is located at 15.9 eV, and the orbital picture of ionization breaks down completely at electron binding energies above 19 eV. If the available experimental momentum profiles demonstrate the dominance of the C 1 conformer, they are in this case clearly not sensitive enough to the molecular conformation for evaluating conformer abundances with accuracies better than 10% due to the limited energy and momentum resolutions and likely physical complications.

  3. Driver's behavioural changes with new intelligent transport system interventions at railway level crossings--A driving simulator study.

    Science.gov (United States)

    Larue, Grégoire S; Kim, Inhi; Rakotonirainy, Andry; Haworth, Narelle L; Ferreira, Luis

    2015-08-01

    Improving safety at railway level crossings is an important issue for the Australian transport system. Governments, the rail industry and road organisations have tried a variety of countermeasures for many years to improve railway level crossing safety. New types of intelligent transport system (ITS) interventions are now emerging due to the availability and the affordability of technology. These interventions target both actively and passively protected railway level crossings and attempt to address drivers' errors at railway crossings, which are mainly a failure to detect the crossing or the train and misjudgement of the train approach speed and distance. This study aims to assess the effectiveness of three emerging ITS that the rail industry considers implementing in Australia: a visual in-vehicle ITS, an audio in-vehicle ITS, as well as an on-road flashing beacons intervention. The evaluation was conducted on an advanced driving simulator with 20 participants per trialled technology, each participant driving once without any technology and once with one of the ITS interventions. Every participant drove through a range of active and passive crossings with and without trains approaching. Their speed approach of the crossing, head movements and stopping compliance were measured. Results showed that driver behaviour was changed with the three ITS interventions at passive crossings, while limited effects were found at active crossings, even with reduced visibility. The on-road intervention trialled was unsuccessful in improving driver behaviour; the audio and visual ITS improved driver behaviour when a train was approaching. A trend toward worsening driver behaviour with the visual ITS was observed when no trains were approaching. This trend was not observed for the audio ITS intervention, which appears to be the ITS intervention with the highest potential for improving safety at passive crossings. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Carryover of maduramicin from feed containing cross-contamination levels into eggs of laying hens.

    Science.gov (United States)

    Bodi, Dorina; Fry, Hildburg; Schafft, Helmut; Lahrssen-Wiederholt, Monika; Preiss-Weigert, Angelika

    2012-07-18

    Maduramicin is a coccidiostat authorized as feed additive in the European Union for chickens and turkeys for fattening but not for laying hens, considering the risk of residues in eggs. The unavoidable cross-contamination of non-target feed with coccidiostats is regulated by Commission Directive 2009/8/EC and resulting carry-over in food by Commission Regulation (EC) No. 124/2009. To verify the compliance of the maximum levels for maduramicin in feed (50 μg/kg) and eggs (2 μg/kg), the carry-over from feed into eggs was investigated. Diets containing 10, 30, and 50 μg of maduramicin/kg of feed were fed to laying hens. Feed, egg white, and yolk were analyzed by LC-MS/MS. Maduramicin residues were only detected in in egg yolk. Feeding the 10 μg/kg maduramicin diet resulted in maduramicin concentrations up to 2.5 μg/kg in whole eggs, already exceeding the maximum level. A carry-over rate of 8% maduramicin from feed into eggs was calculated.

  5. Daily micro-breaks and job performance: General work engagement as a cross-level moderator.

    Science.gov (United States)

    Kim, Sooyeol; Park, YoungAh; Headrick, Lucille

    2018-03-29

    Despite the growing research on work recovery and its well-being outcomes, surprisingly little attention has been paid to at-work recovery and its job performance outcomes. The current study extends the work recovery literature by examining day-level relationships between prototypical microbreaks and job performance as mediated by state positive affect. Furthermore, general work engagement is tested as a cross-level moderator weakening the indirect effects of microbreaks on job performance via positive affect. Using multisource experience sampling method, the authors collected two daily surveys from 71 call center employees and obtained objective records of daily sales performance for two consecutive weeks (n = 632). Multilevel path analysis results showed that relaxation, socialization, and cognitive microbreaks were related to increased positive affect at work which, in turn, predicted greater sales performance. However, breaks for nutrition-intake (having snacks and drinks) did not show significant effects. Importantly, microbreaks had significant indirect effects on job performance via positive affect only for workers who had lower general work engagement, whereas the indirect effects did not exist for workers who had higher general work engagement. Furthermore, Bayesian multilevel analyses confirmed the results. Theoretical and practical implications, limitations, and future research directions are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  6. Institutions for sustainable forest governance: Robustness, equity, and cross-level interactions in Mawlyngbna, Meghalaya, India

    Directory of Open Access Journals (Sweden)

    Christoph Oberlack

    2015-09-01

    Full Text Available This study adopts Ostrom’s Social-Ecological Systems (SES framework in empirical fieldwork to explain how local forestry institutions affect forest ecosystems and social equity in the community of Mawlyngbna in North-East India. Data was collected through 26 semi-structured interviews, participatory timeline development, policy documents, direct observation, periodicals, transect walks, and a concurrent forest-ecological study in the village. Results show that Mawlyngbna's forests provide important sources of livelihood benefits for the villagers. However, ecological disturbance and diversity varies among the different forest ownership types and forest-based livelihood benefits are inequitably distributed. Based on a bounded rationality approach, our analysis proposes a set of causal mechanisms that trace these observed social-ecological outcomes to the attributes of the resource system, resource units, actors and governance system. We analyse opportunities and constraints of interactions between the village, regional, and state levels. We discuss how Ostrom’s design principles for community-based resource governance inform the explanation of robustness but have a blind spot in explaining social equity. We report experiences made using the SES framework in empirical fieldwork. We conclude that mapping cross-level interactions in the SES framework needs conceptual refinement and that explaining social equity of forest governance needs theoretical advances.

  7. Cross-Scale and Cross-Level Dynamics: Governance and Capacity for Resilience in a Social-Ecological System in Taiwan

    Directory of Open Access Journals (Sweden)

    Hsing-Sheng Tai

    2015-02-01

    Full Text Available Resilience thinking has strongly influenced how people understand and pursue sustainability of linked social-ecological systems. Resilience thinking highlights the need to build capacity and manage general system properties in a complex, constantly changing world. I modified an analytical framework to address associations among cross-scale and cross-level dynamics, attributes of governance, and capacity to enhance resilience. The Danungdafu Forestation Area represents one of Taiwan’s most controvisal cases concerning land use, indigenous rights, and environmental issues. Analysis of this Taiwanese experience from a social-ecological perspective can show how current capacities for managing resilience are related to critical governance attributes. Analysis helped identify fundamental flaws in current governance and key issues needing to be addressed. The Danungdafu Forestation Area should transition towards a governance regime that is more participatory, deliberative, multi-layered, accountable, just, and networked. This can be done by developing an intermediate level institution that coordinates the cross-scale and cross-level interactions that better fit this social-ecological system.

  8. Electron transfer behaviour of biological macromolecules towards the single-molecule level

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Grubb, Mikala; Hansen, Allan Glargaard

    2003-01-01

    is combined with state-of-the-art physical electrochemistry with emphasis on single-crystal, atomically planar electrode surfaces, in situ scanning tunnelling microscopy (STM) and other surface techniques. These approaches have brought bioelectrochemistry important steps forward towards the nanoscale...... and single-molecule levels.We discuss here these advances with reference to two specific redox metalloproteins, the blue single-copper protein Pseudomonas aeruginosa azurin and the single-haem protein Saccharomyces cerevisiae yeast cytochrome c, and a short oligonucleotide. Both proteins can be immobilized...... electron transfer (ET) function retained. In situ STM can also address the microscopic mechanisms for electron tunnelling through the biomolecules and offers novel notions such as coherent multi-ET between the substrate and tip via the molecular redox levels. This differs in important respects from...

  9. Influence of the Coulomb interaction in the final state on the cross section of single-electron capture by fast ions

    International Nuclear Information System (INIS)

    Novikov, N.V.; Teplova, Ya.A.

    2011-01-01

    It is shown that the Coulomb interaction of ions in the final state must be taken into account in the estimation of the cross section of electron capture by fast ions. The cross section of electron capture decreases considerably, and the dependence of the cross section on the collision energy becomes close to the experimental one if the interaction of charged particles after collision is taken into account. -- Highlights: → Coulomb interaction of ions in the final state must be taken into account. → This interaction leads to a considerable decrease in the cross section. → The dependence on energy close to the experimental one.

  10. Experimentation and correlates of electronic nicotine delivery system (electronic cigarettes) among university students - A cross sectional study.

    Science.gov (United States)

    Awan, K H

    2016-04-01

    E-cigarettes are becoming popular among youth as safe nicotine delivery systems. Many have expressed concern, however, that e-cigarettes may serve as a gateway to future smoking, given their low perceived risk, or that their use may prevent regular smokers from quitting by maintaining their nicotine addiction. The aim of this study was to assess experimentation with and correlates of e-cigarette use among university students. A cross-sectional study was carried out among 480 university students from four faculties at a university in Riyadh in August-October 2014. A modified version of the World Health Organization's Global Adult Tobacco Survey was used, and multinomial logistic regression was carried out to assess correlations with e-cigarette variables in the whole study sample and among smokers. Almost all students, including the majority of ex-smokers (96.3%) and smokers (94.4%), reported having heard about e-cigarettes. In addition, about one-quarter of the sample (54.2% of smokers, 24.7% of ex-smokers, 6% of never smokers) had experimented with e-cigarettes at least once during their lifetime. Curiosity and peer influence were reported as the main reasons for the use of e-cigarettes. Factors found to be correlated significantly with e-cigarette use were male gender, being a traditional cigarette smoker, having friends who have tried e-cigarettes, and having a strong belief that e-cigarettes could aid smoking cessation. E-cigarettes are popular among Saudi youth, especially among smokers and ex-smokers. Well-designed health education programs and regulatory interventions are required to address this issue.

  11. Differential cross sections for rovibrational (v'=0→1,2,3,4) excitation of the electronic ground state of O2 by electron impact

    International Nuclear Information System (INIS)

    Brunger, M.J.; Middleton, A.G.; Teubner, P.J.

    1998-01-01

    We have measured absolute differential cross sections (DCSs) for rovibrational excitation (0→1,2,3,4) of the χ 3 Σ g - electronic ground state of O 2 . The scattered electron angular range was 10 degree endash 90 degree, while the cross sections were measured at ten specific energies in the 5 endash 20 eV incident beam energy range. This energy regime encompasses the region where the 4 Σ u - and 2 Σ u - resonances of O 2 - are known to significantly enhance the vibrational excitation process. The present data are found to be in generally good agreement with the more limited recent measurements of Allan [J. Phys. B 28, 5163 (1995)] and the earlier results of Wong et al. [Phys. Rev. Lett. 31, 969 (1973)]. Agreement with the data of Shyn and Sweeney [Phys. Rev. A 48, 1214 (1993)], however, was found to be only fair. Comparison of the present DCS with an available Born-closure Schwinger variational method calculation result is also made. copyright 1998 The American Physical Society

  12. Full counting statistics of level renormalization in electron transport through double quantum dots

    International Nuclear Information System (INIS)

    Luo Junyan; Shen Yu; Cen Gang; He Xiaoling; Wang Changrong; Jiao Hujun

    2011-01-01

    We examine the full counting statistics of electron transport through double quantum dots coupled in series, with particular attention being paid to the unique features originating from level renormalization. It is clearly illustrated that the energy renormalization gives rise to a dynamic charge blockade mechanism, which eventually results in super-Poissonian noise. Coupling of the double dots to an external heat bath leads to dephasing and relaxation mechanisms, which are demonstrated to suppress the noise in a unique way.

  13. Farmers' Market Manager's Level of Communication and Influence on Electronic Benefits Transfer (EBT) Adoption at Midwest Farmers' Markets.

    Science.gov (United States)

    Hasin, Afroza; Smith, Sylvia

    2018-01-01

    To understand market managers' level of communication and use of technology that might influence decision to adopt Electronic Benefits Transfer (EBT) at farmers' markets. Cross-sectional study using the Theory of Diffusion of Innovation. Electronic survey administered in midwest states of Illinois, Michigan, and Wisconsin. Farmers' market managers in Illinois, Michigan, and Wisconsin. Information on EBT adoption, market managers' communication, and technology use. Binary logistic regression analysis with EBT adoption as the dependent variable and frequency of technology use, partnership with organizations, farmers' market association (FMA) membership, Facebook page and Web site for the market, and primary source of information as independent variables. Chi-square tests and ANOVA were used to compare states and adopter categories. Logistic regression results showed that the odds of adopting EBT was 7.5 times higher for markets that had partnership with other organizations. Compared with non-adopters, a significantly greater number of early adopters had partnership, FMA membership, and a Facebook page and Web site for market, and reported to a board of directors. Markets that had partnership, FMA membership, a Facebook page and Web site, and mandatory reporting to a board of directors were important factors that influenced EBT adoption at midwest farmers' markets. Copyright © 2017 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  14. The Electronic Structure Signature of the Spin Cross-Over Transition of [Co(dpzca)2

    Science.gov (United States)

    Zhang, Xin; Mu, Sai; Liu, Yang; Luo, Jian; Zhang, Jian; N'Diaye, Alpha T.; Enders, Axel; Dowben, Peter A.

    2018-05-01

    The unoccupied electronic structure of the spin crossover molecule cobalt (II) N-(2-pyrazylcarbonyl)-2-pyrazinecarboxamide, [Co(dpzca)2] was investigated, using X-ray absorption spectroscopy (XAS) and compared with magnetometry (SQUID) measurements. The temperature dependence of the XAS and molecular magnetic susceptibility χmT are in general agreement for [Co(dpzca)2], and consistent with density functional theory (DFT). This agreement of magnetic susceptibility and X-ray absorption spectroscopy provides strong evidence that the changes in magnetic moment can be ascribed to changes in electronic structure. Calculations show the choice of Coulomb correlation energy U has a profound effect on the electronic structure of the low spin state, but has little influence on the electronic structure of the high spin state. In the temperature dependence of the XAS, there is also evidence of an X-ray induced excited state trapping for [Co(dpzca)2] at 15 K.

  15. Automatic cross-sectioning and monitoring system locates defects in electronic devices

    Science.gov (United States)

    Jacobs, G.; Slaughter, B.

    1971-01-01

    System consists of motorized grinding and lapping apparatus, sample holder, and electronic control circuit. Low power microscope examines device to pinpoint location of circuit defect, and monitor displays output signal when defect is located exactly.

  16. Offer And Acceptance In Cross-Border Electronic Contracts: A Brief Comparative Perspective

    OpenAIRE

    Cupido, Robin

    2015-01-01

    Electronic communications have become a widely accepted method of contract conclusion, in part due to the relative ease of contracting afforded to parties who contract inter absentes. The traditional rules of contract law are specifically designed for paper-based contracts, and it is necessary to consider whether these rules would find the same application in contracts concluded electronically. Of particular interest to me is the approach taken to offer and acceptance. This paper will investi...

  17. Phenomenological extraction of two-photon exchange amplitudes from elastic electron-proton scattering cross section data

    Science.gov (United States)

    Qattan, I. A.

    2017-05-01

    Background: The inconsistency in the results obtained from the Rosenbluth separation method and the high-Q2 recoil polarization results on the ratio μpGEp/GMp implies a systematic difference between the two techniques. Several studies suggest that missing higher-order radiative corrections to elastic electron-proton scattering cross section σR(ɛ ,Q2) and in particular hard two-photon-exchange (TPE) contributions could account for the discrepancy. Purpose: In this work, I improve on and extend to low and high Q2 values the extractions of the ɛ dependence of the real parts of the TPE amplitudes relative to the magnetic form factor, as well as the ratio Pl/PlBorn(ɛ ,Q2) by using world data on σR(ɛ ,Q2) with an emphasis on precise new data covering the low-momentum region which is sensitive to the large-scale structure of the nucleon. Method: I combine cross section and polarization measurements of elastic electron-proton scattering to extract the TPE amplitudes. Because the recoil polarization data were confirmed "experimentally" to be essentially independent of ɛ , I constrain the ratio Pt/Pl(ɛ ,Q2) to its ɛ -independent term (Born value) by setting the TPE contributions to zero. This allows for the amplitude YM(ɛ ,Q2) and σR(ɛ ,Q2) to be expressed in terms of the remaining two amplitudes YE(ɛ ,Q2) and Y3(ɛ ,Q2) which in turn are parametrized as second-order polynomials in ɛ and Q2 to reserve as possible the linearity of σR(ɛ ,Q2) as well as to account for possible nonlinearities in the TPE amplitudes. Furthermore, I impose the Regge limit which ensures the vanishing of the TPE contributions to σR(ɛ ,Q2) and the TPE amplitudes in the limit ɛ →1 . Results: I provide simple parametrizations of the TPE amplitudes, along with an estimate of the fit uncertainties. The extracted TPE amplitudes are compared with previous phenomenological extractions and TPE calculations. The Pl/PlBorn ratio is extracted by using the new parametrizations of the TPE

  18. Natriuria and calciuria levels in preeclampsia: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Rose Gasnier

    Full Text Available CONTEXT AND OBJECTIVE Sodium excretion abnormalities in preeclampsia have been studied in relation to several factors. The objective of this study was to compare natriuria (mEq/24 h and calciuria levels (mg/24 h in preeclamptic patients. DESIGN AND SETTING An analytical cross-sectional study with a control group was conducted in the obstetric center and the high-risk pregnancy outpatient clinic at a university hospital in southern Brazil, and in a primary healthcare unit in the same city, including pregnant women with mild preeclampsia, severe preeclampsia or chronic hypertension, and women with normal pregnancies (14 patients in each group. METHOD Natriuria was measured using an ion-selective electrode in an automated clinical chemistry analyzer (Hitache 917, Roche. All the patients collected 24-hour urine, at home or at the hospital, for analysis of proteins, creatinine, calcium, sodium and uric acid. Quantitative variables with asymmetrical distribution were described using the median, minimum and maximum, and were compared using the Kruskal-Wallis test. The results were logarithmically transformed, with one-way analysis of variance (ANOVA by ranks and then the post-hoc Tukey test, and were analyzed by means of the Spearman correlation and receiver operating characteristic (ROC curve. The significance level used was 0.05. RESULTS There were significant differences between the groups in comparing severe preeclampsia with chronic hypertension and severe preeclampsia with controls (P < 0.0001 for both measurements. CONCLUSION Natriuria levels may be lower in preeclampsia when associated with calciuria. Natriuria assessment is an additional test for differential diagnosis of hypertensive diseases in pregnancy, but is a poor predictor when used alone.

  19. A practical approach to temperature effects in dissociative electron attachment cross sections using local complex potential theory

    International Nuclear Information System (INIS)

    Sugioka, Yuji; Takayanagi, Toshiyuki

    2012-01-01

    Highlights: ► Dissociative electron attachment cross sections for polyatomic molecules are calculated by a simple theoretical approach. ► Temperature effects can be reasonably reproduced with the present model. ► All the degrees-of-freedom are taken into account in the present dynamics approach. -- Abstract: We propose a practical computational scheme to obtain temperature dependence of dissociative electron attachment cross sections to polyatomic molecules within a local complex potential theory formalism. First we perform quantum path-integral molecular dynamics simulations on the potential energy surface for the neutral molecule in order to sample initial nuclear configurations as well as momenta. Classical trajectories are subsequently integrated on the potential energy surface for the anionic state and survival probabilities are simultaneously calculated along the obtained trajectories. We have applied this simple scheme to dissociative electron attachment processes to H 2 O and CF 3 Cl, for which several previous studies are available from both the experimental and theoretical sides.

  20. Effects of Cross-Linking on the Hydrostatic Pressure Testing for HDPE Pipe Material using Electron Beam Machine

    International Nuclear Information System (INIS)

    Mohd Jamil Bin Hashim

    2011-01-01

    One of the most inventive, sustainable strategies used in engineering field is to improve the quality of material and minimize production cost of material for example in this paper is HDPE material. This is because HDPE is an oil base material. This paper proposes to improve its hydrostatic pressure performance for HDPE pipe. The burst test is the most direct measurement of a pipe materials resistance to hydrostatic pressure. Test will be conducted in accordance with ASTM standard for HDPE pipe that undergo electron beam irradiation cross-linking. Studies show the effect of electron beam irradiation will improve the mechanical properties of HDPE pipe. When cross-linking is induced, the mechanical properties such as tensile strength and young modulus is increase correspond to the radiation dose. This happen because the structure of HDPE, which is thermoplastic change to thermosetting. This will indicate the variability of irradiation dose which regard to the pipe pressure rating. Hence, the thickness ratio of pipe will be re-examining in order to make the production of HDPE pipe become more economical. This research review the effects of electron beam on HDPE pipe, as well as to reduce the cost of its production to improve key properties of selected plastic pipe products. (author)