Science.gov

Sample records for neon isoelectronic sequence

  1. 2s -> np Autoionizing Resonances of the Neon Isoelectronic Sequence using RRPA and RMQDT

    NASA Astrophysics Data System (ADS)

    Madugula, Nrisimha Murty; Rundhe, Milind V.; Aravind, Gopalan; Deshmukh, Pranawa C.; Manson, Steven T.

    2012-06-01

    Extensive theoretical and experimental studies of the photoionization of various atoms and ions have been carried out over long period of time [1, 2] owing both to the fundamental importance of the process and to the many applications, e.g., astrophysical and atmospheric modeling, plasma dynamics, etc. In the present work, we report our studies of the 2s -> np autoionizing resonances in the Ne isoelectronic sequence, of significance due to the cosmic abundance of these systems [2-4]. In particular, Ne, Na^+, Mg^2+, Al^3+ and Sc^11+ have been studied. The study has been performed within the framework of the relativistic random-phase approximation (RRPA) [5] and relativistic multichannel quantum defect theory (RMQDT) [6]. The resonances have been characterized in terms of position, width and shape, i.e., Fano profiles [7, 8], and the evolution of the parameters of the resonances along the sequence has been investigated.[4pt] [1] A. Neogi et al, Phys. Rev. A 67, 042707 (2003). [2] H. S. Chakraborty et al, Phys. Rev. Lett. 83, 2151 (1999). [3] H. S. Chakraborty et al, Ap. J. 595, 1307 (2003). [4] G. Nasreen Haque, Ph.D. thesis (unpublished), Georgia State University, Atlanta, USA (1991). [5] W.R. Johnson et al, Phys. Scr. 21, 409 (1980). [6] C. M. Lee and W.R. Johnson, Phys. Rev. A 22, 979 (1980). [7] U. Fano and J. W. Cooper, Phys. Rev. A 40, 441 (1968). [8] W.R. Johnson, et al, Phys. Rev. A 22, 989 (1980).

  2. Labeling conventions in isoelectronic sequences

    SciTech Connect

    Maniak, S.T.; Curtis, L.J. )

    1990-08-01

    The isoelectronic exposition of atomic structure properties involves labeling ambiguities when more than one level of the same total angular momentum and parity is present, and an energy ordered labeling of these levels can lead to apparent isoelectronic discontinuities. For example, in the recent oscillator strength calculations for S-like ions by Saloman and Kim (Phys. Rev. A 38, 577 (1988)), abrupt changes in the rates were sometimes observed between one isoelectronic element and the next. We suggest an alternative labeling scheme that removes these discontinuities and produces a smooth isoelectronic variation. This alternative labeling offers advantages for data exposition and for semiempirical interpolation and extrapolation.

  3. Isoelectronic trends of line strength data in the Li and Be isoelectronic sequences

    SciTech Connect

    Trabert, E; Curtis, L J

    2006-03-01

    The decays of the 2p J = 1/2 and J = 3/2 levels of Li-like ions and of the 2s2p {sup 1,3}P{sub 1}{sup 0} levels of Be-like ions can be used as simple-atom test beds for experimental lifetime measurements and for the development of accurate calculations of the transition rates. They have summarized and filtered the experimental data in order to obtain consistent data sets and isoelectronic trends that can be compared to theoretical predictions. The graphical presentation of line strength data enables direct comparison and evaluation of the merit of data along extended isoelectronic sequences. From this, the precision that is necessary in future meaningful experiments can be deduced.

  4. Radioactive transitions in the helium isoelectronic sequence

    NASA Technical Reports Server (NTRS)

    Dalgarno, A.

    1971-01-01

    The principles of the atomic spectrum theory are used to quantitatively analyze radiation transitions in two-electron helium-like atomic systems. Quantum theoretical methods, describing absorption and emission of a single photon in a radiative transition between two stationary states of an atomic system, reproduced the energy level diagram for the low lying states of helium. Reliable values are obtained from accurate variationally determined two-electron nonrelativistic wave functions for radiative transition probabilities of 2 3p states in the helium isoelectric sequence, and for the 2 1s and 2 3s1 states of the helium sequence.

  5. Systematic in the relativistic oscillator strengths for fine-structure transitions in the aluminium isoelectronic sequence.

    NASA Astrophysics Data System (ADS)

    Lavin, C.; Alvarez, A. B.; Martin, I.

    1997-06-01

    Theoretical oscillator strengths for 3s23p 2P-3s23d 2D, 3s23p 2P-3s24s 2S and 3s24s 2S-3s24p 2P fine-structure transitions in some ions of the aluminium isoelectronic sequence are reported. The computations have been carried out with two formalisms within the context of quantum defect theory: the quantum defect orbital method (QDO) and its relativistic counterpart (RQDO). The advantages of including relativistic effects are made apparent. Some of these are reflected by the correct systematic trends displayed by the RQDO f-values along the isoelectronic sequence.

  6. Quantum-defect studies of transitions in the diffuse spectral series of the potassium isoelectronic sequence.

    NASA Astrophysics Data System (ADS)

    Lavin, C.; Barrientos, C.; Martín, I.

    1992-05-01

    Theoretical oscillator strengths are reported for transitions in the diffuse spectral series of some members of the potassium isoelectronic sequence (K I-Cr VI). The calculations have been performed with the Quantum Defect Orbital (QDO) method. A core-polarization correction to the dipole transition moment has also been included in the formalism.

  7. Relativistic MR-MP energy levels: Low-lying states in the Mg isoelectronic sequence

    NASA Astrophysics Data System (ADS)

    Santana, Juan A.

    2016-09-01

    The relativistic Multi-Reference Møller-Plesset (MR-MP) many-body perturbation theory was applied to calculate the energies of all excited states within the 3s3p, 3p2, 3s3d, 3p3d and 3d2 configurations for every ion of the Mg isoelectronic sequence (Z = 12 - 100). The results are compared with previous calculations and available experimental data. The MR-MP excitation energies agree with experiment typically within 100 ppm over a wide range of Z, particularly for mid- and high-range Z. Experimental data for highly charged ions in this isoelectronic sequence are limited and the complete and accurate dataset presented here is expected to ease the identification process upon measurements.

  8. Relativistic oscillator strengths for transitions in the principal spectral series of the silver isoelectronic sequence

    NASA Astrophysics Data System (ADS)

    Martín, I.; Almaraz, M. A.; Lavin, C.

    1995-12-01

    In a very recent paper [1] we have reported oscillator strengths for fine structure transitions between levels belonging to the diffuse and sharp spectral series in the silver isoelectronic sequence. The calculations were performed with the quantum defect orbital method in both their non-relativistic (QDO) and relativistic (RQDO) formulations, with both implicit and explicit allowance for core-valence polarisation. We now present a parallel study of transitions belonging to the ns 2 S- n'2 P( n=5, 6; n'=5-10) spectral series of the AgI sequence, up to Z=63 in some cases.

  9. Spectral lines behavior of Be I and Na I isoelectronic sequence in Debye plasma environment

    NASA Astrophysics Data System (ADS)

    Chaudhuri, Rajat K.; Chattopadhyay, Sudip; Sinha Mahapatra, Uttam

    2012-08-01

    We report the plasma screening effect on the first ionization potential (IP) and [He]2s2(1S0)→[He]2s2p /2s3p allowed (P11) and inter-combination transitions (P31) in some selected Be-like ions. In addition, we investigate the spectral properties of [Ne]3s (2S1/2)→[Ne]np(2P1/2 and P23/2 for n = 3, 4) transitions in Ca X and Fe XVI ions (Na I isoelectronic sequence) and [He]3s(2S1/2)→[He]np(2P1/2 and P23/2 for n = 2, 3) transitions in Li, B II, and N IV (Li I isoelectronic sequence) under plasma environment. The state-of-the-art relativistic coupled cluster calculations using the Debye model of plasma for electron-nucleus interaction show that (a) the ionization potential decreases sharply with increasing plasma strength and (b) the gap between the [He]2s2(1S0)→[He]2s2p(1,3P1) energy levels increases with increasing plasma potential and nuclear charge. It is found that the [He]2s2 (1S0)→2s3p(1,3P1) transition energy decreases uniformly with increasing plasma potential and nuclear charge. In other words, the spectral lines associated with 2s-2p (i.e., Δn=0, where n corresponds to principle quantum number) transitions in Be I isoelectronic sequence exhibit a blue-shift (except for Be I, B II, and the lowest inter-combination line in C III, which exhibit a red-shift), whereas those associated with 2s-3p (i.e., Δn≠0) transitions are red-shifted. Similar trend is observed in Li I and Na I isoelectronic sequences, where spectral lines associated with Δn=0 (Δn≠0) are blue-shifted (red-shifted). The effect of Coulomb screening on the spectral lines of ions subjected to plasma is also addressed.

  10. Kinetic Correlation In Photo-Double-Ionization Processes: The He-Isoelectronic Sequence

    SciTech Connect

    Otranto, S.; Garibotti, C. R.

    2006-01-09

    Analytical models proposed to represent the two-electron continuum are revisited. Main results obtained with these models are summarized. Recent studies of the photo-double-ionization (PDI) of the He-isoelectronic sequence by means of the recently introduced SC3 model are shown and compared with the results predicted by classical and semi-classical Wannier approaches. By fitting the triply differential cross sections (TDCSs) with the usual dipolar Gaussian form we find that the width has a power dependence on excess energy with exponent 0.25 in the near threshold region and departs from this law with increasing energy.

  11. S-matrix Calculations of Energy Levels of the Lithium Isoelectronic Sequence

    SciTech Connect

    sapirstein, J; Cheng, K T

    2010-11-02

    A QED approach to the calculation of the spectra of the lithium isoelectronic sequence is implemented. A modified Furry representation based on the Kohn-Sham potential is used to evaluate all one- and two-photon diagrams with the exception of the two-loop Lamb shift. Three-photon diagrams are estimated with Hamiltonian methods. After incorporating recent calculations of the two-loop Lamb shift and recoil corrections a comprehensive tabulation of the 2s, 2p{sub 1/2} and 2p{sub 3/2} energy levels as well as the 2s - 2p{sub 1/2} and 2s - 2p{sub 3/2} transition energies for Z = 10 - 100 is presented.

  12. VizieR Online Data Catalog: B-like iso-electronic sequence (Liang+, 2012)

    NASA Astrophysics Data System (ADS)

    Liang, G. Y.; Badnell, N. R.; Zhao, G.

    2012-09-01

    We present our calculated data including energy levels, radiative decay rates and effective collision strengths for all the transitions among the 204 fine-structure levels of boron-like iso-electronic sequence, belonging to configurations of 2sx 2py (x+y=3), 2s2 3l, 2s2 4l, 2s 2p 3l, 2s 2p 4l, 2p2 3l The effective collision strengths at 13 temperatures ranging from 2x102(q+1)2 to 2x106(q+1)2^K, where q is the residual charge of ions, i.e. Z-5, have been calculated using the ICFT R-matrix method. The data format adopts ADAS adf04 format, see the file at website http://www.adas.ac.uk/man/appxa-04.pdf Filename format: sequenceauthor(nospace)yearelement(nospace)charge.dat. For example Ne^5+, blikelgy12ne5.dat (2 data files).

  13. Excitation energies, polarizabilities, multipole transition rates, and lifetimes of ions along the francium isoelectronic sequence

    SciTech Connect

    Safronova, U. I.; Johnson, W. R.; Safronova, M. S.

    2007-10-15

    Relativistic many-body perturbation theory is applied to study properties of ions of the francium isoelectronic sequence. Specifically, energies of the 7s, 7p, 6d, and 5f states of Fr-like ions with nuclear charges Z=87-100 are calculated through third order; reduced matrix elements, oscillator strengths, transition rates, and lifetimes are determined for 7s-7p, 7p-6d, and 6d-5f electric-dipole transitions; and 7s-6d, 7s-5f, and 5f{sub 5/2}-5f{sub 7/2} multipole matrix elements are evaluated to obtain the lifetimes of low-lying excited states. Moreover, for the ions Z=87-92 calculations are also carried out using the relativistic all-order single-double method, in which single and double excitations of Dirac-Fock wave functions are included to all orders in perturbation theory. With the aid of the single-double wave functions, we obtain accurate values of energies, transition rates, oscillator strengths, and the lifetimes of these six ions. Ground state scalar polarizabilities in Fr I, Ra II, Ac III, and Th IV are calculated using relativistic third-order and all-order methods. Ground state scalar polarizabilities for other Fr-like ions are calculated using a relativistic second-order method. These calculations provide a theoretical benchmark for comparison with experiment and theory.

  14. Scaling of collisionally pumped 3s-3p lasers in the neon isoelectronic sequence

    NASA Technical Reports Server (NTRS)

    Feldman, U.; Seely, J. F.; Bhatia, A. K.

    1984-01-01

    Atomic-number scaling in the 3p-3s population-inversion and plasma parameters of neonlike ions of Si, Ar, Ti, Fe, Ge, and Kr is investigated theoretically. The population levels are calculated; the Z-scaling relationships are defined; the results are presented in tables and graphs; and the implications for the laser gain are explored. Laser gain in excess of 1/cm are predicted for all ions except Si V, with a peak of 30/cm for Fe XVII at electron density 10 to the 21st/cu cm.

  15. Static electric dipole polarizabilities for isoelectronic sequences. II. Open-shell S statesa2

    NASA Astrophysics Data System (ADS)

    Koch, Volker; Andrae, Dirk

    2013-07-01

    We present static electric dipole polarizabilities α d( Z,N) from numerical nonrelativistic restricted Hartree-Fock (RHF) finite-field calculations for high-spin open-shell S states ( L = 0) of atoms and isoelectronic ions with N ≤ 55 electrons. All these S states result from one or more half-filled shells. For eight isoelectronic sequences, those with N = 3, 7, 11, 15, 23, 29, 33 or 41 electrons where the electronic ground state of the neutral or nearly neutral members is conserved upon increase of the nuclear charge number Z, polarizability data are given for ions with charge number Q = Z - N up to Q = 90. In addition, these data are represented in terms of rational functions of Q (with absolute value of the relative error of the fit always below 4%). The rational functions are comparable to the classical nonrelativistic result α d( Z,1) = 4.5 / Z 4 = 4.5 / ( Q + 1)4 for the polarizability of the 2S ground state of a hydrogen-like system. Our results also contribute to constitute a reference database (i) for algebraic approaches relying on basis functions, and (ii) for the discussion of relativistic and correlation effects on polarizabilities along isoelectronic sequences.

  16. Spectroscopic studies of highly ionized atoms: New results for the Ne, Mg, Mn, Fe, Co, Ga and Ge isoelectronic sequences

    NASA Astrophysics Data System (ADS)

    Zeng, Xiantang

    The electron structure of several highly charged ions, belonging to the Mg, Ne, Mn, Fe, Co, Ga and Ge isoelectronic sequences, has been experimentally studied by means of two techniques, beam-foil spectroscopy, BFS, and the spectroscopy of laser-produced plasmas, LPP. The investigations were carried out at Lund University, LU, in 1989-90 and at the China Institute of Atomic Energy, CIAE, Beijing, from 1990 on. In Lund the spectra Br IX - Br XI (belonging to Co, Fe and Mn sequences, respectively) were studied by BFS, using the 3 MV Pelletron tandem accelerator. The LPP investigations, in which a 1.5 GW Nd(YAG) laser system was utilized, dealt with highly charged ions belonging to the Ga and Ge isoelectronic sequences. Many previously unknown transitions were observed and new energy levels were established. The observations were corroborated by theoretical calculations with the relativistic Hartree- Fock code, HFR, by R. D. Cowan. At CIAE a beamline for atomic physics experiments was designed and constructed in the 14 MV tandem accelerator laboratory. The instrumentation includes a high- resolution 2.2 m grazing incidence monochromator for the spectral region 10-1000 Å. This monochromator, which compares favorably with commercially available instruments, was designed and built in China. Spectra of highly charged S, Ni, Cu, Ge and Br have already been recorded at CIAE. The thesis includes detailed results, for Ne-like Br XXVI and Mg-like Br XXIV. In both spectra about 20 previously unknown energy levels were established. Parallel with the experimental work HFR calculations were performed. Theory and experiment are in very satisfactory agreement. Also, future atomic physics investigations at CIAE are briefly discussed in the thesis.

  17. Proton collisional excitation in the lowest lying 3P terms of ions in the Be and Mg isoelectronic sequences

    NASA Technical Reports Server (NTRS)

    Landman, D. A.; Brown, T.

    1979-01-01

    Proton collisional excitation cross sections and rate constants are presented for transitions between the 3P(J) fine-structure levels of the lowest-lying sp configurations in a number of astrophysically important ions belonging to the Be and Mg isoelectronic sequences. The calculations were made by direct integration of the Schroedinger equation resulting from semiclassical Coulomb excitation theory. The cross sections and rate constants for the 3P(J) transitions in the lowest-lying P(2) configurations are expected to be similar to those for the corresponding sp configuration transitions, and this is illustrated for C III. For the high-temperature ion Ca XVII alpha particle excitation is shown to be unimportant for situations involving ordinary values of the He/H abundance ratio. A simple, but apparently accurate method for determining certain radial integrals for low-lying excited configurations is proposed.

  18. Hylleraas-configuration-interaction nonrelativistic energies for the {sup 1}S ground states of the beryllium isoelectronic sequence

    SciTech Connect

    Sims, James S.; Hagstrom, Stanley A.

    2014-06-14

    In a previous work, Sims and Hagstrom [“Hylleraas-configuration-interaction study of the 1 {sup 1}S ground state of neutral beryllium,” Phys. Rev. A 83, 032518 (2011)] reported Hylleraas-configuration-interaction (Hy-CI) method variational calculations for the {sup 1}S ground state of neutral beryllium with an estimated accuracy of a tenth of a microhartree. In this work, the calculations have been extended to higher accuracy and, by simple scaling of the orbital exponents, to the entire Be 2 {sup 1}S isoelectronic sequence. The best nonrelativistic energies for Be, B{sup +}, and C{sup ++} obtained are −14.6673 5649 269, −24.3488 8446 36, and −36.5348 5236 25 hartree, respectively. Except for Be, all computed nonrelativistic energies are superior to the known reference energies for these states.

  19. Electron-impact excitation-autoionization in the cadmium isoelectronic sequence: A case of target term dependence in scattering theory

    NASA Astrophysics Data System (ADS)

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

    1983-05-01

    Excitation-autoionization contributions to electron-impact ionization are calculated for several atomic ions in the cadmium isoelectronic sequence. We calculate excitation cross sections in the distorted-wave approximation and compare them in one case to a calculation in the close-coupling approximation. We focus attention on the 4d105s2-->4d95s2nf innershell excitations in In+, Sb3+, and Xe6+. Hartree-Fock atomic structure calculations for the 4d95s2nf configurations are found to be highly term dependent. Thus our predictions for the total ionization cross section from the 5s subshell for these ions exhibit strong target term dependence. Our Xe6+ results are found to be in excellent agreement with the recent experimental crossed-beam measurements of Gregory and Crandall.

  20. Hylleraas-configuration-interaction nonrelativistic energies for the ¹S ground states of the beryllium isoelectronic sequence.

    PubMed

    Sims, James S; Hagstrom, Stanley A

    2014-06-14

    In a previous work, Sims and Hagstrom ["Hylleraas-configuration-interaction study of the 1 (1)S ground state of neutral beryllium," Phys. Rev. A 83, 032518 (2011)] reported Hylleraas-configuration-interaction (Hy-CI) method variational calculations for the (1)S ground state of neutral beryllium with an estimated accuracy of a tenth of a microhartree. In this work, the calculations have been extended to higher accuracy and, by simple scaling of the orbital exponents, to the entire Be 2 (1)S isoelectronic sequence. The best nonrelativistic energies for Be, B(+), and C(++) obtained are -14.6673 5649 269, -24.3488 8446 36, and -36.5348 5236 25 hartree, respectively. Except for Be, all computed nonrelativistic energies are superior to the known reference energies for these states.

  1. R-matrix electron-impact excitation data for the Mg-like iso-electronic sequence

    NASA Astrophysics Data System (ADS)

    Fernández-Menchero, L.; Del Zanna, G.; Badnell, N. R.

    2014-12-01

    Aims: Emission lines from ions in the Mg-like iso-electronic sequence can be used as reliable diagnostics of temperature and density of astrophysical and fusion plasmas over a wide range of parameters. Data in the literature are quite lacking, there are no calculations for many of the ions in the sequence. Methods: We have carried-out intermediate coupling frame transformation R-matrix calculations which include a total of 283 fine-structure levels in both the configuration interaction target and close-coupling collision expansions. These arise from the configurations 1s2 2s2 2p6 3 {s,p,d} nl with n = 4,5, and for l = 0-4. Results: We obtain ordinary collision strengths and Maxwell-averaged effective collision strengths for the electron-impact excitation of all the ions of the Mg-like sequence, from Al+ to Zn18 +. We compare our results with those from previous R-matrix and distorted waves calculations, where available, for some benchmark ions. We find good agreement with the results of previous calculations for the transitions n = 3-3. We also find good agreement for the most intense transitions n = 3-4. These transitions are important for populating the upper levels of the main diagnostic lines. These data are made available in the APAP archive via http://www.apap-network.org, CHIANTI via http://www.chiantidatabase.org and open-ADAS via http://open.adas.ac.uk

  2. R-matrix electron-impact excitation data for the Be-like iso-electronic sequence

    NASA Astrophysics Data System (ADS)

    Fernández-Menchero, L.; Del Zanna, G.; Badnell, N. R.

    2014-06-01

    Aims: Emission lines from ions in the Be-like isoelectronic sequence can be used for reliable diagnostics of temperature and density of astrophysical and fusion plasmas over a wide range of temperatures. Surprisingly, interpolated data is all that is available for a number of astrophysically important ions. Methods: We have carried out intermediate coupling frame transformation R-matrix calculations which include a total of 238 fine-structure levels in both the configuration interaction target and close-coupling collision expansions. These arise from the configurations 1s2 2 {s, p} nl with n = 3-7, and l = 0-4 for n ≤ 5 and l = 0-2 for n = 6,7. Results: We obtain ordinary collision strengths and Maxwell-averaged effective collision strengths for the electron-impact excitation of all the ions of the Be-like sequence, from B+ to Zn26+. We compare with previous R-matrix calculations and interpolated values for some benchmark ions. We find good agreement for transitions n = 2-2 with previous R-matrix calculations but some disagreements with interpolated values. We also find good agreement for the most intense transitions n = 2-3 which contribute via cascade to the (n = 2) diagnostic radiating levels. These data are made available in the archives of APAP via http://www.apap-network.org and OPEN-ADAS via http://open.adas.ac.uk

  3. R-matrix electron-impact excitation data for the Na-like iso-electronic sequence

    NASA Astrophysics Data System (ADS)

    Liang, G. Y.; Whiteford, A. D.; Badnell, N. R.

    2009-06-01

    We present results for the outer-shell electron-impact excitation of all Na-like ions from Mg+ to Kr25+ obtained using the intermediate-coupling frame transformation R-matrix approach. For each ion's calculation, the target and close-coupling expansions are both taken to be the 18 LS terms (32 levels) belonging to configurations [ 1s^22s^22p^6] 3l, 4l, 5l and 6l (l = 0-5). Effective collision strengths (Upsilons;) are presented at temperatures ranging from 2×10^2(q+1)2 K to 2×10^6(q+1)2 K (where q is the residual charge of ions, i.e. Z-11). Detailed comparisons for the Upsilons; are made with the results of previous calculations for several ions, which span the sequence. Furthermore, we examine the iso-electronic trends of both low- and high-temperature effective collision strengths These data are made available in the archives of APAP via http://www.apap-network.org, OPEN-ADAS via http://open.adas.ac.uk as well as anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/500/1263

  4. Calculation of levels, transition rates, and lifetimes for the arsenic isoelectronic sequence Sn XVIII-Ba XXIV, W XLII

    NASA Astrophysics Data System (ADS)

    Wang, K.; Chen, Z. B.; Chen, C. Y.; Yan, J.; Dang, W.; Zhao, X. H.; Yang, X.

    2017-09-01

    Multi-configuration Dirac-Fock (MCDF) calculations of energy levels, wavelengths, oscillator strengths, lifetimes, and electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), magnetic quadrupole (M2) transition rates are reported for the arsenic isoelectronic sequence Sn XVIII-Ba XXIV, W XLII. Results are presented among the 86 levels of the 4s2 4p3, 4 s 4p4, 4p5, 4s2 4p2 4 d, and 4 s 4p3 4 d configurations in each ion. The relativistic atomic structure package GRASP2K is adopted for the calculations, in which the contributions from the correlations within the n ≤ 7 complexes, Breit interaction (BI) and quantum electrodynamics (QED) effects are taking into account. The many-body perturbation theory (MBPT) method is also employed as an independent calculation for comparison purposes, taking W XLII as an example. Calculated results are compared with data from other calculations and the observed values from the Atomic Spectra Database (ASD) of the National Institute of Standards and Technology (NIST). Good agreements are obtained. i.e, the accuracy of our energy levels is assessed to be better than 0.6%. These accurate theoretical data should be useful for diagnostics of hot plasmas in fusion devices.

  5. Comparison of Theoretical and Experimental Level Values of the n = 2 Configurations in the Boron Isoelectronic Sequence

    NASA Astrophysics Data System (ADS)

    Edlén, Bengt

    1983-10-01

    The examination of the level values of the n = 2 configurations, which was recently carried through for ions iso-electronic with Li, Be, O and F, has now been extended to the configurations 2s22p, 2s2p2 and 2p3 of the boron sequence. In this study, expressions of the form A + B(Z - C)-1 + a(Z - s)x are derived for the difference between observed and theoretical values of selected level intervals, the theoretical values being based on the calculations of Cheng, Kim and Desclaux. By this procedure, accidental errors in the experimental data are smoothed out and missing data are interpolated or extrapolated beyond the range of observations. In the case of the two strongly interacting levels 2s2p2 2S1/2, 2P1/2, however, the theory fails to reproduce the effects of the "avoided crossing" well enough to provide a useful frame of reference, and a more primitive method of extrapolation had to be used. The results of the examination are summarized in a table of recommended values for the 14 excited levels of the n = 2 complex, covering the range from Z = 7 to Z = 36, and a corresponding table of recalculated wavelengths, including intersystem combinations. Some experimental data reported in the literature are found to need revision.

  6. K-Shell Photoabsorption and Photoionisation of Trace Elements I. Isoelectronic Sequences With Electron Number 3< or = N < or = 11

    NASA Technical Reports Server (NTRS)

    Palmeri, P.; Quinet, P.; Mendoza, C.; Bautista, M. A.; Witthoeft, M. C.; Kallman, T. R.

    2016-01-01

    Context. With the recent launching of the Hitomi X-ray space observatory, K lines and edges of chemical elements with low cosmic abundances, namely F, Na, P, Cl, K, Sc, Ti, V, Cr, Mn, Co, Cu and Zn, can be resolved and used to determine important properties of supernova remnants, galaxy clusters and accreting black holes and neutron stars.Aims. The second stage of the present ongoing project involves the computation of the accurate photoabsorption and photoionisation cross sections required to interpret the X-ray spectra of such trace elements.Methods. Depending on target complexity and computer tractability, ground-state cross sections are computed either with the close-coupling Breit-Pauli R-matrix method or with the autostructure atomic structure code in the isolated-resonance approximation. The intermediate-coupling scheme is used whenever possible. In order to determine a realistic K-edge behaviour for each species, both radiative and Auger dampings are taken into account, the latter being included in the R-matrix formalism by means of an optical potential.Results. Photoabsorption and total and partial photoionisation cross sections are reported for isoelectronic sequences with electron numbers 3< or = N< or = 11. The Na sequence (N=11) is used to estimate the contributions from configurations with a 2s hole (i.e. [2s]) and those containing 3d orbitals, which will be crucial when considering sequences with N 11.Conclusions. It is found that the [2s/u] configurations must be included in the target representations of species with N> 11 as they contribute significantly to the monotonic background of the cross section between the L and K edges. Configurations with 3d orbitals are important in rendering an accurate L edge, but they can be practically neglected in the K-edge region.

  7. R-matrix electron-impact excitation data for the B-like iso-electronic sequence

    NASA Astrophysics Data System (ADS)

    Liang, G. Y.; Badnell, N. R.; Zhao, G.

    2012-11-01

    We have carried-out parallel intermediate-coupling frame transformation R-matrix calculations for electron-impact excitation amongst the 204 close-coupling levels of the 2sx2py (x + y = 3), 2s2{3,4}l, 2s2p{3,4}l, and 2p23l configurations for all boron-like ions from C+ to Kr31+. We have also included the configuration interaction due to the 2p24l, 2s3l3l' and 2p3s3l configurations. A detailed comparison has been made of the target structure and excitation data for four specific ions (viz., Ne5+, Ar13+, Fe21+ and Kr31+) that span the sequence, so as to assess the accuracy over the entire sequence. Effective collision strengths (Υs) are presented at temperatures ranging from 2 × 102(z + 1)2 K to 2 × 106(z + 1)2 K (where z is the residual charge of the ions, i.e. Z - 5). Detailed comparisons for the (effective) collision strengths (Υs) Ω are made with the results of previous calculations for the four representative ions. Furthermore, we examine the iso-electronic trends of the effective collision strengths as a function of temperature. These data are made available in the archives of APAP via http://www.apap-network.org, OPEN-ADAS via http://open.adas.ac.uk as well as at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/547/A87

  8. R-matrix electron-impact excitation data for the Ne-like iso-electronic sequence

    NASA Astrophysics Data System (ADS)

    Liang, G. Y.; Badnell, N. R.

    2010-07-01

    We present results for the electron-impact excitation of all Ne-like ions from Na+ to Kr26+ obtained using the intermediate-coupling frame transformation R-matrix approach. For each ion's calculation, the close-coupling expansion is taken to be the 113 LS terms (209 levels) belonging to the configurations [1s2] 2s22p6, 2s22p5{3, 4, 5}l, 2s2p6{3, 4, 5}l (l ∈ s, p, d, f, and g), and 2s22p5{6, 7}l' (l' ∈ s, p, and d). An additional configuration interaction effect arising from configurations of 2s22p43l{3, 4, 5}l'' (l'' ∈ s, p, d, f and g) was included in the target expansion. A detailed comparison of the target structure has been made for six specific ions (Si4+, Ar8+, Ca10+, Fe16+, Ni18+, and Kr26+) spanning the sequence to assess the accuracy for the entire sequence. Effective collision strengths (Υs) are presented at temperatures ranging from 2 × 102(q+1)2 K to 2 × 106(q + 1)2 K (where q is the residual charge of ions, i.e. Z - 10). Detailed comparisons for the Υs are made with the results of previous calculations for several ions, which span the sequence. Furthermore, we examine the iso-electronic trends of effective collision strengths as a function of temperature. The present results are the only R-matrix ones for the majority of the ions and the most extensive and complete data for modelling to-date. These data are made available in the archives of APAP via http://www.apap-network.org, OPEN-ADAS via http://open.adas.ac.uk as well as anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/518/A64

  9. K-shell photoabsorption and photoionization of trace elements. II. Isoelectronic sequences with electron number 12 ≤N ≤ 18

    NASA Astrophysics Data System (ADS)

    Mendoza, C.; Bautista, M. A.; Palmeri, P.; Quinet, P.; Witthoeft, M. C.; Kallman, T. R.

    2017-08-01

    Context. We are concerned with improving the diagnostic potential of the K lines and edges of elements with low cosmic abundances, namely F, Na, P, Cl, K, Sc, Ti, V, Cr, Mn, Co, Cu, and Zn, that are observed in the X-ray spectra of supernova remnants, galaxy clusters, and accreting black holes and neutron stars. Aims: Since accurate photoabsorption and photoionization cross sections are needed in their spectral models, they have been computed for isoelectronic sequences with electron number 12 ≤ N ≤ 18 using a multi-channel method. Methods: Target representations are obtained with the atomic structure code autostructure, and ground-state cross sections are computed with the Breit-Pauli R-matrix method (bprm) in intermediate coupling, including damping (radiative and Auger) effects. Results: Following the findings in our earlier work on sequences with 2 ≤ N ≤ 11, the contributions from channels associated with the 2s-hole [2s] μ target configurations and those containing 3d orbitals are studied in the Mg (N = 12) and Ar (N = 18) isoelectronic sequences. Cross sections for the latter ions are also calculated in the isolated-resonance approximation as implemented in autostructure and compared with bprm to test their accuracy. Conclusions: It is confirmed that the collisional channels associated with the [2s] μ target configurations must be taken into account owing to significant increases in the monotonic background cross section between the L and K edges. Target configurations with 3d orbitals give rise to fairly conspicuous unresolved transition arrays in the L-edge region, but to a much lesser extent in the K-edge that is our main concern; therefore, they have been neglected throughout owing to their computationally intractable channel inventory, thus allowing the computation of cross sections for all the ions with 12 ≤ N ≤ 18 in intermediate coupling with bprm. We find that the isolated-resonance approximations performs satisfactorily and will be our

  10. R-matrix electron-impact excitation data for the Li-like iso-electronic sequence including Auger and radiation damping

    NASA Astrophysics Data System (ADS)

    Liang, G. Y.; Badnell, N. R.

    2011-04-01

    We present results for the electron-impact excitation of all Li-like ions from Be+ to Kr33+ which we obtained using the radiation- and Auger-damped intermediate-coupling frame transformation R-matrix approach. We have included both valence- and core-electron excitations up to the 1s25l and 1s2l4l' levels, respectively. A detailed comparison of the target structure and collision data has been made for four specific ions (O5+, Ar15+, Fe23+ and Kr33+) spanning the sequence so as to assess the accuracy for the entire sequence. Effective collision strengths (Υs) are presented at temperatures ranging from 2 × 102(z + 1)2 K to 2 × 106(z + 1)2 K (where z is the residual charge of the ions, i.e. Z - 3). Detailed comparisons for the Υs are made with the results of previous calculations for several ions which span the sequence. The radiation and Auger damping effects were explored for core-excitations along the iso-electronic sequence. Furthermore, we examined the iso-electronic trends of effective collision strengths as a function of temperature. These data are made available in the archives of APAP via http://www.apap-network.org, OPEN-ADAS via http://open.adas.ac.uk, as well as anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/528/A69

  11. Isoelectronic co-doping

    DOEpatents

    Mascarenhas, Angelo

    2004-11-09

    Isoelectronic co-doping of semiconductor compounds and alloys with deep acceptors and deep donors is used to decrease bandgap, to increase concentration of the dopant constituents in the resulting alloys, and to increase carrier mobilities lifetimes. Group III-V compounds and alloys, such as GaAs and GaP, are isoelectronically co-doped with, for example, N and Bi, to customize solar cells, thermal voltaic cells, light emitting diodes, photodetectors, and lasers on GaP, InP, GaAs, Ge, and Si substrates. Isoelectronically co-doped Group II-VI compounds and alloys are also included.

  12. Data-based methods for isoelectronic prediction of atomic lifetimes and energy levels

    NASA Astrophysics Data System (ADS)

    Curtis, Lorenzo J.

    1993-11-01

    The use of data-based semiempirical methods to produce high precision predictions and systematizations along isoelectronic sequences is discussed and applied to several examples. Applications include: studies of trends in the lifetimes of resonance transitions in alkali-like isoelectronic sequences; the combined systematization of spin-allowed and spin-forbidden transition probabilities in alkaline earth-like and inert gas-like isoelectronic sequences; the use of screening and quantum defect parametrizations to predict ionization potentials for the Be sequence.

  13. Energy levels, lifetimes, and transition rates for the selenium isoelectronic sequence Pd XIII-Te XIX, Xe XXI-Nd XXVII, W XLI

    NASA Astrophysics Data System (ADS)

    Wang, K.; Yang, X.; Chen, Z. B.; Si, R.; Chen, C. Y.; Yan, J.; Zhao, X. H.; Dang, W.

    2017-09-01

    Energy levels, wavelengths, lifetimes, oscillator strengths, and electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), magnetic quadrupole (M2) transition rates among the 46 fine structure levels belonging to the ([ Ar ] 3d10) 4s2 4p4, ([ Ar ] 3d10) 4s2 4p3 4 d, and ([ Ar ] 3d10) 4 s 4p5 configurations for the selenium isoelectronic sequence Pd XIII-Te XIX, Xe XXI-Nd XXVII, W XLI are reported. These data are determined in the multi-configuration Dirac-Fock (MCDF) approach, in which relativistic effects, main electron correlations within the n = 7 complex, Breit interaction (BI), and quantum electrodynamic (QED) corrections are included. The many-body perturbation theory (MBPT) method is also employed as an independent calculation to confirm the present accuracy, taking W XLI as an example. Comparisons and analysis are made between the present results and available experimental and theoretical ones, and good agreements are obtained. These accurate data are expected to be useful in nuclear fusion research and astrophysical applications.

  14. Laser gain on 3p-3d and 3s-3p transitions and X-ray line ratios for the nitrogen isoelectronic sequence

    NASA Technical Reports Server (NTRS)

    Feldman, U.; Seely, J. F.; Bhatia, A. K.

    1989-01-01

    Results are presented on calculations of the 72 levels belonging to the 2s(2)2p(3), 2s2p(4), 2p(5), 2s(2)2p(2)3s, 2s(2)2p(2)3p, and 2s(2)2p(2)3d configurations of the N I isoelectronic sequence for the ions Ar XII, Ti XVI, Fe XX, Zn XXIV, and Kr XXX, for electron densities up to 10 to the 24th/cu cm. It was found that large population inversions and gain occur between levels in the 2s(2)2p(2)3p configuration and levels in the 2s(2)2p(2)3d configuration that cannot decay to the ground configuration by an electric dipole transition. For increasing electron densities, the intensities of the X-ray transitions from the 2s(2)2p(2)3p configuration to the ground configuration decrease relative to the transitions from the 2s(2)2p(2)3s and 2s(2)2p(2)3d configurations to the ground configuration. The density dependence of these X-ray line ratios is presented.

  15. K-shell photoabsorption and photoionisation of trace elements. I. Isoelectronic sequences with electron number 3 ≤N ≤ 11

    NASA Astrophysics Data System (ADS)

    Palmeri, P.; Quinet, P.; Mendoza, C.; Bautista, M. A.; Witthoeft, M. C.; Kallman, T. R.

    2016-05-01

    Context. With the recent launching of the Hitomi X-ray space observatory, K lines and edges of chemical elements with low cosmic abundances, namely F, Na, P, Cl, K, Sc, Ti, V, Cr, Mn, Co, Cu and Zn, can be resolved and used to determine important properties of supernova remnants, galaxy clusters and accreting black holes and neutron stars. Aims: The second stage of the present ongoing project involves the computation of the accurate photoabsorption and photoionisation cross sections required to interpret the X-ray spectra of such trace elements. Methods: Depending on target complexity and computer tractability, ground-state cross sections are computed either with the close-coupling Breit-Pauli R-matrix method or with the autostructure atomic structure code in the isolated-resonance approximation. The intermediate-coupling scheme is used whenever possible. In order to determine a realistic K-edge behaviour for each species, both radiative and Auger dampings are taken into account, the latter being included in the R-matrix formalism by means of an optical potential. Results: Photoabsorption and total and partial photoionisation cross sections are reported for isoelectronic sequences with electron numbers 3 ≤ N ≤ 11. The Na sequence (N = 11) is used to estimate the contributions from configurations with a 2s hole (i.e. [2s]μ) and those containing 3d orbitals, which will be crucial when considering sequences with N > 11. Conclusions: It is found that the [2s]μ configurations must be included in the target representations of species with N ≥ 11 as they contribute significantly to the monotonic background of the cross section between the L and K edges. Configurations with 3d orbitals are important in rendering an accurate L edge, but they can be practically neglected in the K-edge region.

  16. Comparison of Theoretical and Experimental Level Values of the n = 2 Configurations in the Nitrogen Isoelectronic Sequence

    NASA Astrophysics Data System (ADS)

    Edlén, Bengt

    1984-08-01

    Observed level intervals within and between the configurations 2s2 2p3, 2s2p4 and 2p5 of the nitrogen sequence are compared with the corresponding theoretical values derived from the tables of Cheng, Kim and Desclaux. The differences are expressed by suitable functions of Z which give the systematic correction to the theoretical values and reveal the accidental errors in the experimental values. The technique is the same as was used in previous examinations of the Li, Be, B, O and F sequences. The results are summarized in tables of recommended level values (Z = 10-36) and recalculated wavelengths.

  17. CALCULATIONS WITH SPECTROSCOPIC ACCURACY: ENERGIES AND TRANSITION RATES IN THE NITROGEN ISOELECTRONIC SEQUENCE FROM Ar XII TO Zn XXIV

    SciTech Connect

    Wang, K.; Dang, W.; Si, R.; Guo, X. L.; Hutton, R.; Chen, C. Y.; Jönsson, P.; Li, S.; Zhang, H.; Long, F. Y.; Liu, H. T.; Li, D. F.; Yan, J.; Chen, Z. B. E-mail: chychen@fudan.edu.cn

    2016-03-15

    Combined relativistic configuration interaction and many-body perturbation calculations are performed for the 359 fine-structure levels of the 2s{sup 2} 2p{sup 3}, 2 s2p{sup 4}, 2p{sup 5}, 2s{sup 2} 2p{sup 2} 3l, 2 s2p{sup 3} 3l, 2p{sup 4} 3l, and 2s{sup 2} 2p{sup 2} 4l configurations in N-like ions from Ar xii to Zn xxiv. Complete and consistent data sets of energies, wavelengths, radiative rates, oscillator strengths, and line strengths for all possible electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transitions among the 359 levels are given for each ion. The present work significantly increases the amount of accurate data for ions in the nitrogen-like sequence, and the accuracy of the energy levels is high enough to enable the identification and interpretation of observed spectra involving the n = 3, 4 levels, for which experimental values are largely scarce. Meanwhile, the results should be of great help for modeling and diagnosing astrophysical and fusion plasmas.

  18. Study of the 4p2, 5p2 and 5s5f excited configurations of the Zn and Cd isoelectronic sequences, using relativistic and non-relativistic semiempirical approaches

    NASA Astrophysics Data System (ADS)

    Di Rocco, Héctor O.; Raineri, Mónica; Reyna-Almandos, Jorge G.

    2016-11-01

    The consistency of the energy levels published for configurations 4p2, 5p2 and 5s5f belonging to Zn and Cd isoelectronic sequences is studied. Different semiempirical approaches considering the linearity of the Slater integrals for large Zc, the smoothness of the sF screening parameters, the energy values in terms of Z (or Zc), and the differences of the Ecalc - Eexp values are used, where Ecalc values are energies calculated with a Hartree-Hock method with relativistic corrections and superposition of configurations (HFR-SOC), and Eexp are the experimental values. For the np2 configurations both LS and relativistic jj expressions are considered. Configuration 5s5f is also analyzed taking into account the Landé's interval rule.

  19. Ionization Potentials for Isoelectronic Series.

    ERIC Educational Resources Information Center

    Agmon, Noam

    1988-01-01

    Presents a quantitative treatment of ionization potentials of isoelectronic atoms. By looking at the single-electron view of calculating the total energy of an atom, trends in the screening and effective quantum number parameters are examined. Approaches the question of determining electron affinities. (CW)

  20. Excited states of Ne isoelectronic ions: SAC-CI study

    NASA Astrophysics Data System (ADS)

    Das, A. K.; Ehara, M.; Nakatsuji, H.

    2001-01-01

    Excited states of the s, p, and d symmetries up to principal quantum number n = 4 are studied for the first eight members of Ne isoelectronic sequence (Ne to Cl7+) by the SAC-CI (symmetry-adapted-cluster configuration-interaction) method. The valence STO basis sets of Clementi et al. and the optimized excited STO are used by the STO-6G expansion method. The calculated transition energies agree well with the experimental values wherever available.

  1. Theoretical studies of massive stars. I - Evolution of a 15-solar-mass star from the zero-age main sequence to neon ignition

    NASA Technical Reports Server (NTRS)

    Endal, A. S.

    1975-01-01

    The evolution of a star with mass 15 times that of the sun from the zero-age main sequence to neon ignition has been computed by the Henyey method. The hydrogen-rich envelope and all shell sources were explicitly included in the models. An algorithm has been developed for approximating the results of carbon burning, including the branching ratio for the C-12 + C-12 reaction and taking some secondary reactions into account. Penetration of the convective envelope into the core is found to be unimportant during the stages covered by the models. Energy transfer from the carbon-burning shell to the core by degenerate electron conduction becomes important after the core carbon-burning stage. Neon ignition will occur in a semidegenerate core and will lead to a mild 'flash.' Detailed numerical results are given in an appendix. Continuation of the calculations into later stages and variations with the total mass of the star will be discussed in later papers.

  2. Be I isoelectronic ions embedded in hot plasma.

    PubMed

    Saha, B; Fritzsche, S

    2006-03-01

    The influence of plasma screening on the 2s(2 1)S0-->2s2p(3)p(0)1 intercombination and the 2s(2 1)S0-->2s2p(1)p(0)1 allowed transitions is investigated theoretically for several ions along the isoelectronic sequence (C III, N IV, O V, Si XI, Fe XXIII, and Mo XXXIX). For the case of a weakly coupled hot plasma, multiconfiguration Dirac-Fock computations have been carried out for these ions by considering a (time averaged) Debye-Hückel potential for both the "electron-nucleus" and "electron-electron" interaction. The plasma screening is found to enlarge the 2s(2 1)S0-->2s2p(3)p(0)1 excitation energy uniformly along the Be I isoelectronic sequence, leading to an increasing blueshift of this intercombination line as the nuclear charge is increased. For the 2s(2 1)S0-->2s2p(1)p(0)1 resonance line, in contrast, the transition energy is either blueshifted or redshifted in dependence of the screening parameter and owing to a cancellation of the plasma screening on the electron-nucleus and electron-electron interaction. This interplay of the (external) plasma screening with the internal interactions in the berylliumlike ions leads, for instance, to a shift of the resonance transition from red to blue in going from O V to Si XI ions. Apart from the screening effects on the transition energies, we also investigate their influence on the oscillator strengths and emission rates along the Be I isoelectronic sequence.

  3. Portable neon purification system

    SciTech Connect

    Richardson, R.A.; Schmitt, R.L.

    1995-08-01

    This paper describes the principle design features of a portable neon purification system and the results of the system performance testing. Neon gas replaces air in the Ring Imaging Cherenkov detector without using vacuum, in experiment E781(SELEX) at Fermilab. The portable neon purification system purifies neon gas by, first purging air with CO{sub 2}, freezing the CO{sub 2}, then cryoadsorbing the remaining contaminants. The freezer removes carbon dioxide from a neon gas mixture down to a maximum concentration of 500 parts-per-million (ppm). The charcoal bed adsorber removes nitrogen from neon gas down to a maximum concentration of 100 ppm. The original RICH vessel was designed to hold vacuum but its photomultiplier tube plates were not.

  4. Positron excitation of neon

    NASA Technical Reports Server (NTRS)

    Parcell, L. A.; Mceachran, R. P.; Stauffer, A. D.

    1990-01-01

    The differential and total cross section for the excitation of the 3s1P10 and 3p1P1 states of neon by positron impact were calculated using a distorted-wave approximation. The results agree well with experimental conclusions.

  5. NEON VISUALIZATION ENVIRONMENT

    DTIC Science & Technology

    2017-07-28

    NEON VISUALIZATION ENVIRONMENT NEXT CENTURY CORPORATION JULY 2017 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED...specifications, or other data does not license the holder or any other person or corporation ; or convey any rights or permission to manufacture, use, or sell...this collection of information is estimated to average 1 hour per response , including the time for reviewing instructions, searching existing data

  6. The Helium Atom and Isoelectronic Ions in Two Dimensions

    ERIC Educational Resources Information Center

    Patil, S. H.

    2008-01-01

    The energy levels of the helium atom and isoelectronic ions in two dimensions are considered. The difficulties encountered in the analytical evaluation of the perturbative and variational expressions for the ground state, promote an interesting factorization of the inter-electronic interaction, leading to simple expressions for the energy. This…

  7. The Helium Atom and Isoelectronic Ions in Two Dimensions

    ERIC Educational Resources Information Center

    Patil, S. H.

    2008-01-01

    The energy levels of the helium atom and isoelectronic ions in two dimensions are considered. The difficulties encountered in the analytical evaluation of the perturbative and variational expressions for the ground state, promote an interesting factorization of the inter-electronic interaction, leading to simple expressions for the energy. This…

  8. The spectrum of NeH. A comparative isoelectronic study

    NASA Astrophysics Data System (ADS)

    Martin, I.; Pérez-Delgado, Y.; Lavín, C.

    1999-05-01

    Einstein coefficients and oscillator strengths for Rydberg-ground and Rydberg-Rydberg transitions in the rare-gas excimer NeH have been calculated with the quantum defect orbital (QDO) method. A comparative study of analogous transitions in NeH and in some of its isoelectronic Rydberg radicals has revealed clear similarities between them.

  9. High pressure neon arc lamp

    DOEpatents

    Sze, Robert C.; Bigio, Irving J.

    2003-07-15

    A high pressure neon arc lamp and method of using the same for photodynamic therapies is provided. The high pressure neon arc lamp includes a housing that encloses a quantity of neon gas pressurized to about 500 Torr to about 22,000 Torr. At each end of the housing the lamp is connected by electrodes and wires to a pulse generator. The pulse generator generates an initial pulse voltage to breakdown the impedance of the neon gas. Then the pulse generator delivers a current through the neon gas to create an electrical arc that emits light having wavelengths from about 620 nanometers to about 645 nanometers. A method for activating a photosensitizer is provided. Initially, a photosensitizer is administered to a patient and allowed time to be absorbed into target cells. Then the high pressure neon arc lamp is used to illuminate the target cells with red light having wavelengths from about 620 nanometers to about 645 nanometers. The red light activates the photosensitizers to start a chain reaction that may involve oxygen free radicals to destroy the target cells. In this manner, a high pressure neon arc lamp that is inexpensive and efficiently generates red light useful in photodynamic therapy is provided.

  10. Quantum defect orbital study of the sodium isoelectronic sequence

    NASA Astrophysics Data System (ADS)

    Martin, Inmaculada; Karwowski, Jacek; Lavin, Carmen; Diercksen, Geerd H. F.

    1991-12-01

    The quantum defect orbital (QDO) method and its relativistic (RQDO) counterpart have been applied to the calculation of oscillator strengths for the 3s 2S → 3p 2Po, 3p 2Po → 3d 2D, 3d 2D → 4f 2Fo, and 3d 2D → 5f 2Fo transitions in sodium-like atoms. The consequences of including relativistic effects are demonstrated.

  11. Laying the groundwork for NEON's continental-scale ecological research

    NASA Astrophysics Data System (ADS)

    Dethloff, G.; Denslow, M.

    2013-12-01

    The National Ecological Observatory Network (NEON) is designed to examine a suite of ecological issues. Field-collected data from 96 terrestrial and aquatic sites across the U.S. will be combined with remotely sensed data and existing continental-scale data sets. Field collections will include a range of physical and biological types, including soil, sediment, surface water, groundwater, precipitation, plants, animals, insects, and microbes as well as biological sub-samples such as leaf material, blood and tissue samples, and DNA extracts. Initial data analyses and identifications of approximately 175,000 samples per year will occur at numerous external laboratories when all sites are fully staffed in 2017. Additionally, NEON will archive biotic and abiotic specimens at collections facilities where they will be curated and available for additional analyses by the scientific community. The number of archived specimens is currently estimated to exceed 130,000 per year by 2017. We will detail how NEON is addressing the complexities and challenges around this set of analyses and specimens and how the resulting high-quality data can impact ecological understanding. The raw data returned from external laboratories that is quality checked and served by NEON will be the foundation for many NEON data products. For example, sequence-quality nucleic acids extracted from surface waters, benthic biofilms, and soil samples will be building blocks for data products on microbial diversity. The raw sequence data will also be available for uses such as evolutionary investigations, and the extracts will be archived so others can acquire them for additional research. Currently, NEON is establishing contracts for the analysis and archiving of field-collected samples through 2017. During this period, NEON will gather information on the progress and success of this large-scale effort in order to determine the most effective course to pursue with external facilities. Two areas that NEON

  12. Reduction of magnetic interlayer coupling in barlowite through isoelectronic substitution

    NASA Astrophysics Data System (ADS)

    Guterding, Daniel; Valentí, Roser; Jeschke, Harald O.

    2016-09-01

    Materials with a perfect kagome lattice structure of magnetic ions are intensively sought after, because they may exhibit exotic ground states like a quantum spin liquid phase. Barlowite is a natural mineral that features perfect kagome layers of copper ions. However, in barlowite there are also copper ions between the kagome layers, which mediate strong interkagome couplings and lead to an ordered ground state. Using ab initio density functional theory calculations we investigate whether selective isoelectronic substitution of the interlayer copper ions is feasible. After identifying several promising candidates for substitution we calculate the magnetic exchange couplings based on crystal structures predicted from first-principles calculations. We find that isoelectronic substitution with nonmagnetic ions significantly reduces the interkagome exchange coupling. As a consequence, interlayer-substituted barlowite can be described by a simple two-parameter Heisenberg Hamiltonian, for which a quantum spin liquid ground state has been predicted.

  13. Low energy (e,2e) measurements of CH4 and neon in the perpendicular plane.

    PubMed

    Nixon, Kate L; Murray, Andrew James; Chaluvadi, Hari; Amami, Sadek; Madison, Don H; Ning, Chuangang

    2012-03-07

    Low energy experimental and theoretical triple differential cross sections for the highest occupied molecular orbital of methane (1t(2)) and for the 2p atomic orbital of neon are presented and compared. These targets are iso-electronic, each containing 10 electrons and the chosen orbital within each target has p-electron character. Observation of the differences and similarities of the cross sections for these two species hence gives insight into the different scattering mechanisms occurring for atomic and molecular targets. The experiments used perpendicular, symmetric kinematics with outgoing electron energies between 1.5 eV and 30 eV for CH(4) and 2.5 eV and 25 eV for neon. The experimental data from these targets are compared with theoretical predictions using a distorted-wave Born approximation. Reasonably good agreement is seen between the experiment and theory for neon while mixed results are observed for CH(4). This is most likely due to approximations of the target orientation made within the model.

  14. Divergence analysis of atomic ionization processes and isoelectronic series

    SciTech Connect

    Lopez-Rosa, S.; Angulo, J. C.; Antolin, J.; Esquivel, R. O.

    2009-07-15

    Fisher divergences (FDs) and Jensen-Shannon divergences (JSDs) are used in this work to quantify the informational discrepancies between the one-particle electron densities of neutral atoms, singly charged ions, and isoelectronic series. These dissimilarity magnitudes, computed for a set of 319 atomic systems in both position and momentum spaces, provide relevant information concerning pattern, structure, and periodicity properties of the ionization processes. In particular an apparent correlation between extremal values of the atomic ionization potential and the divergences is found. Results are compared with those obtained by quantum similarity techniques.

  15. Thermoelectric properties of isoelectronically substituted bismuth compounds: a computational study

    NASA Astrophysics Data System (ADS)

    Liangruksa, Monrudee

    2017-03-01

    This work focuses on using isoelectronic substitution to modify electronic density of states (DOS) of bismuth (Bi) compounds for thermoelectric property modification. The calculations include first-principle density functional theory (DFT) and analytical calculations based on Mott formula. The thermoelectric materials selected in the present study are Bi compounds, i.e. Bi2Te3, Bi2Se3, Bi2Se2Te, Bi2Te2Se, Bi2O2Te, and Bi2O2Se. The results reveal that isoelectronic substitution of Se and Te atoms with O atoms (Bi2O2Te and Bi2O2Se) introduces changes in DOS around the valence band maximum and the conduction band minimum, exhibiting the figure of merit (ZT) approaching the values 0.004 and 0.03 at room temperature, for Bi2O2Se and Bi2O2Te, respectively. Though the ZT of these oxide compounds are inferior to conventional thermoelectric materials, it is known that they show better stability and less toxicity which could be the alternative materials.

  16. Isoelectronic line intensity ratios for plasma electron temperature measurement (invited)

    NASA Astrophysics Data System (ADS)

    Marjoribanks, Robin S.; Budnik, Fredric; Kulcsár, Gábor; Zhao, Liang

    1995-01-01

    Strictly speaking, temperature is uniquely defined only in plasmas which are in complete thermodynamic equilibrium. In typical laser-produced plasmas, measurement of electron temperature amounts to a parametrization of some part of the distribution of electron energies, typically inferred from the recombination continuum, or from the ratio of spectral lines that are implicitly dependent on the electron distribution. Where the plasma is highly transient, suffers appreciable opacity, or is subject to a background radiation field, the interpretation of temperature from disparate spectral lines can become untrustworthy. For these complicated plasmas, a conceptually simpler spectral line diagnostic offers great advantages. A technique has been introduced that begins with plasmas that include two elements of similar atomic number, in a known ratio, and compares isoelectronic lines from ions that differ only in their nuclear charge Z, and thus in their ionization potentials χi. Since these two have different values of the same dimensionless parameter Te/χi, the ratio of intensities of isoelectronic lines can be interpreted to determine the temperature Te. The technique and its areas of advantage are described, the applications made to the special problems of laboratories elsewhere are summarized, and this particular progress in application to laser plasmas produced by high-intensity picosecond pulses are reported here.

  17. Biexciton emission from single isoelectronic traps formed by nitrogen-nitrogen pairs in GaAs

    SciTech Connect

    Takamiya, Kengo; Fukushima, Toshiyuki; Yagi, Shuhei; Hijikata, Yasuto; Yaguchi, Hiroyuki; Mochizuki, Toshimitsu; Yoshita, Masahiro; Akiyama, Hidefumi; Kuboya, Shigeyuki; Onabe, Kentaro; Katayama, Ryuji

    2013-12-04

    We have studied photoluminescence (PL) from individual isoelectronic traps formed by nitrogen-nitrogen (NN) pairs in GaAs. Sharp emission lines due to exciton and biexciton were observed from individual isoelectronic traps in nitrogen atomic-layer doped (ALD) GaAs. The binding energy of biexciton bound to individual isoelectronic traps was approximately 8 meV. Both the exciton and biexciton luminescence lines show completely random polarization and no fine-structure splitting. These results are desirable to the application to the quantum cryptography used in the field of quantum information technology.

  18. Rogue mantle helium and neon.

    PubMed

    Albarède, Francis

    2008-02-15

    The canonical model of helium isotope geochemistry describes the lower mantle as undegassed, but this view conflicts with evidence of recycled material in the source of ocean island basalts. Because mantle helium is efficiently extracted by magmatic activity, it cannot remain in fertile mantle rocks for long periods of time. Here, I suggest that helium with high 3He/4He ratios, as well as neon rich in the solar component, diffused early in Earth's history from low-melting-point primordial material into residual refractory "reservoir" rocks, such as dunites. The difference in 3He/4He ratios of ocean-island and mid-ocean ridge basalts and the preservation of solar neon are ascribed to the reservoir rocks being stretched and tapped to different extents during melting.

  19. Fisher-Shannon analysis of ionization processes and isoelectronic series

    SciTech Connect

    Sen, K. D.; Antolin, J.; Angulo, J. C.

    2007-09-15

    The Fisher-Shannon plane which embodies the Fisher information measure in conjunction with the Shannon entropy is tested in its ability to quantify and compare the informational behavior of the process of atomic ionization. We report the variation of such an information measure and its constituents for a comprehensive set of neutral atoms, and their isoelectronic series including the mononegative ions, using the numerical data generated on 320 atomic systems in position, momentum, and product spaces at the Hartree-Fock level. It is found that the Fisher-Shannon plane clearly reveals shell-filling patterns across the periodic table. Compared to position space, a significantly higher resolution is exhibited in momentum space. Characteristic features in the Fisher-Shannon plane accompanying the ionization process are identified, and the physical reasons for the observed patterns are described.

  20. Energy levels of isoelectronic impurities by large scale LDA calculations

    SciTech Connect

    Li, Jingbo; Wang, Lin-Wang

    2002-11-22

    Isoelectronic impurity states are localized states induced by stoichiometric single atom substitution in bulk semiconductor. Photoluminescence spectra indicate deep impurity levels of 0.5 to 0.9eV above the top of valence band for systems like: GaN:As, GaN:P, CdS:Te, ZnS:Te. Previous calculations based on small supercells seemingly confirmed these experimental results. However, the current ab initio calculations based on thousand atom supercells indicate that the impurity levels of the above systems are actually much shallower(0.04 to 0.23 eV), and these impurity levels should be compared with photoluminescence excitation spectra, not photoluminescence spectra.

  1. The Hg isoelectronic defect in ZnO

    SciTech Connect

    Cullen, J.; McGlynn, E. Henry, M. O.; Johnston, K.; Dunker, D.; Bayer, M.; Yakovlev, D. R.

    2013-11-21

    We report a study of the luminescence due to Hg in ZnO, concentrating on the main zero phonon line (ZPL) at 3.2766(1) eV and its associated phonon sidebands. For a sample implanted with radioactive {sup 192}Hg, the ZPL intensity, normalised to that of shallow bound exciton emission, is observed to decrease with an equivalent half-life of 4.5(1) h, very close to the 4.85(20) h half-life of {sup 192}Hg. ZnO implanted with stable Hg impurities produces the same luminescence spectrum. Temperature dependent measurements confirm that the zero phonon line is a thermalizing doublet involving one allowed and one largely forbidden transition from excited states separated by 0.91(1) meV to a common ground state. Uniaxial stress measurements show that the allowed transition takes place from an orbitally degenerate excited state to a non-degenerate ground state in a centre of trigonal (C{sub 3v}) symmetry while the magneto-optical properties are characteristic of electron-hole pair recombination at an isoelectronic defect. The doublet luminescence is assigned to bound exciton recombination involving exchange-split Γ{sub 5} and Γ{sub 1,2} excited states (using C{sub 6v} symmetry labels; Γ{sub 3} and Γ{sub 1,2} using C{sub 3v} labels) at isoelectronic Hg impurities substituting for Zn in the crystal. The electron and hole g values deduced from the magneto-optical data indicate that this Hg impurity centre in ZnO is hole-attractive.

  2. X-ray Emission Line Anisotropy Effects on the Isoelectronic Temperature Measurement Method

    NASA Astrophysics Data System (ADS)

    Liedahl, Duane; Barrios, Maria; Brown, Greg; Foord, Mark; Gray, William; Hansen, Stephanie; Heeter, Robert; Jarrott, Leonard; Mauche, Christopher; Moody, John; Schneider, Marilyn; Widmann, Klaus

    2016-10-01

    Measurements of the ratio of analogous emission lines from isoelectronic ions of two elements form the basis of the isoelectronic method of inferring electron temperatures in laser-produced plasmas, with the expectation that atomic modeling errors cancel to first order. Helium-like ions are a common choice in many experiments. Obtaining sufficiently bright signals often requires sample sizes with non-trivial line optical depths. For lines with small destruction probabilities per scatter, such as the 1s2p-1s2 He-like resonance line, repeated scattering can cause a marked angular dependence in the escaping radiation. Isoelectronic lines from near-Z equimolar dopants have similar optical depths and similar angular variations, which leads to a near angular-invariance for their line ratios. Using Monte Carlo simulations, we show that possible ambiguities associated with anisotropy in deriving electron temperatures from X-ray line ratios are minimized by exploiting this isoelectronic invariance.

  3. Demonstrating Fluorescence with Neon Paper and Plastic

    ERIC Educational Resources Information Center

    Birriel, Jennifer J.; Roe, Clarissa

    2015-01-01

    Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and…

  4. Demonstrating Fluorescence with Neon Paper and Plastic

    ERIC Educational Resources Information Center

    Birriel, Jennifer J.; Roe, Clarissa

    2015-01-01

    Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and…

  5. 21 CFR 868.1670 - Neon gas analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Neon gas analyzer. 868.1670 Section 868.1670 Food... DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1670 Neon gas analyzer. (a) Identification. A neon gas analyzer is a device intended to measure the concentration of neon in a gas mixture exhaled by a...

  6. 21 CFR 868.1670 - Neon gas analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Neon gas analyzer. 868.1670 Section 868.1670 Food... DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1670 Neon gas analyzer. (a) Identification. A neon gas analyzer is a device intended to measure the concentration of neon in a gas mixture exhaled by a...

  7. 21 CFR 868.1670 - Neon gas analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neon gas analyzer. 868.1670 Section 868.1670 Food... DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1670 Neon gas analyzer. (a) Identification. A neon gas analyzer is a device intended to measure the concentration of neon in a gas mixture exhaled by a...

  8. 21 CFR 868.1670 - Neon gas analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Neon gas analyzer. 868.1670 Section 868.1670 Food... DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1670 Neon gas analyzer. (a) Identification. A neon gas analyzer is a device intended to measure the concentration of neon in a gas mixture exhaled by a...

  9. United atoms to superatoms and the isoelectronic principle

    NASA Astrophysics Data System (ADS)

    Peppernick, Samuel John

    The work described in this thesis pertains to the photoelectron spectroscopy of negatively charged atomic ions and their superatomic counterparts. The molecular ions studied in this work, TiO-, ZrO -, and WC- can be interpreted as superatomic manifestations of the respective isoelectronic elements appearing on the periodic table. The superposition principle, in the context of the unified atom picture from molecular orbital theory, allows for the assignment of molecular electronic transitions to be referenced to the atomic frame. This approach represents a novel method of determining the electronic state origins of transitions appearing in the photoelectron spectra of molecular anions by directly comparing the known spectroscopy for the isoelectronic element. In Chapter 3, a remarkable correspondence is presented between the separate PADs produced independently by TiO- and Ni- , suggesting the bound ionic state of the diatomic is mimicking that present in the negative atomic ion. Application of the beta-wave approach provides supporting evidence that the dominant photodetachment channel in TiO- arises from electron emission of the highest ocuupied 9sigma molecular orbital. This provides an immediate assignment of the ground electronic state of TiO- as the doublet 2Delta 3/2 configuration. Similarly, the ground electronic state of Ni - is 2D5/2 with 4s orbital ejection describing the ground state electron affinity transition. Obtained in Chapter 4 is an improved measurement of the electron affinity of ZrO-, determined to be 1.29(1) eV. This energy arises from the assigned anion to neutral ground state, 1Sigma + ← 2Sigma-, electronic transition. Further indentified are features assigned to the 2Delta 3/2 and 2Delta5/2 electronically excited states of the anion, with the 2Delta3/2 spin orbit component measured to lie ˜ 0.10 eV above the 2Sigma - ground state. The first measurement of the photoelectron binding energy spectrum of Pt-, at a fixed frequency photon

  10. Chromatic induction in neon colour spreading.

    PubMed

    da Pos, Osvaldo; Bressan, Paola

    2003-03-01

    Neon colour spreading occurs when sections of a lattice are replaced by segments of a different colour. This colour appears to diffuse out of the segments, and produce a slightly tinted transparent surface floating above the lattice. In two of the four experiments reported here, observers varied the colour of an area in a test display, until it matched the neon colour perceived in a corresponding (illusory) area in a comparison display. We found that the neon colour is an additive mixture of the colour of the segments and the colour complementary to the lattice, as suggested by Bressan (Vision Research 35 (1995) 375). In the other two experiments, we separately manipulated the presence and alignment of lattice and segments, to test whether the neon effect is fully predicted by a combination of colour diffusion and simultaneous colour contrast. We found that the colour induced in a neon figure is more saturated than the colour induced in a comparable non-neon figure. We discuss the implications of these results on our current understanding of the mechanisms of neon colour spreading.

  11. Small scale demand type neon liquefaction plant

    NASA Technical Reports Server (NTRS)

    Dube, W. P.; Slifka, A. J.; Bitsy, R. M.; Sparks, L. L.; Johnson, K. B.

    1990-01-01

    Low-temperature measurement of the thermal conductivity of insulating materials is generally made using a boil-off calorimetry technique involving liquid hydrogen (LH2). Liquid neon (LNe) has nearly the same normal boiling point as LH2, but has a much larger heat of vaporization, allowing extended run times. The main drawback of using LNe has been its excessive cost; $170.00 versus $1.50/l for LH2 (1989 prices). A neon liquefaction plant has been designed and constructed to capture, purify, and refrigerate the neon boil-off from calorimetry experiments. Recycling the neon reduces operating costs to approximately $20/l. The system consists of a purification section, a heat exchanger, LNe and LH2 storage dewars, and a fully automated control system. After purification, neon is liquified in the heat exchanger by LH2 flowing countercurrently through stainless steel cooling coils. Hydrogen flow is automatically adjusted to keep the neon at its normal saturation temperature, 27 K. The liquid neon is then stored in a dewar placed directly below the heat exchanger.

  12. Small scale demand type neon liquefaction plant

    NASA Technical Reports Server (NTRS)

    Dube, W. P.; Slifka, A. J.; Bitsy, R. M.; Sparks, L. L.; Johnson, K. B.

    1990-01-01

    Low-temperature measurement of the thermal conductivity of insulating materials is generally made using a boil-off calorimetry technique involving liquid hydrogen (LH2). Liquid neon (LNe) has nearly the same normal boiling point as LH2, but has a much larger heat of vaporization, allowing extended run times. The main drawback of using LNe has been its excessive cost; $170.00 versus $1.50/l for LH2 (1989 prices). A neon liquefaction plant has been designed and constructed to capture, purify, and refrigerate the neon boil-off from calorimetry experiments. Recycling the neon reduces operating costs to approximately $20/l. The system consists of a purification section, a heat exchanger, LNe and LH2 storage dewars, and a fully automated control system. After purification, neon is liquified in the heat exchanger by LH2 flowing countercurrently through stainless steel cooling coils. Hydrogen flow is automatically adjusted to keep the neon at its normal saturation temperature, 27 K. The liquid neon is then stored in a dewar placed directly below the heat exchanger.

  13. Charge radii of neon isotopes across the sd neutron shell

    SciTech Connect

    Marinova, K.; Geithner, W.; Kappertz, S.; Kloos, S.; Kotrotsios, G.; Neugart, R.; Wilbert, S.; Kowalska, M.; Keim, M.; Blaum, K.; Lievens, P.; Simon, H.

    2011-09-15

    We report on the changes in mean square charge radii of unstable neon nuclei relative to the stable {sup 20}Ne, based on the measurement of optical isotope shifts. The studies were carried out using collinear laser spectroscopy on a fast beam of neutral neon atoms. High sensitivity on short-lived isotopes was achieved thanks to nonoptical detection based on optical pumping and state-selective collisional ionization, which was complemented by an accurate determination of the beam kinetic energy. The new results provide information on the structural changes in the sequence of neon isotopes all across the neutron sd shell, ranging from the proton drip line nucleus and halo candidate {sup 17}Ne up to the neutron-rich {sup 28}Ne in the vicinity of the ''island of inversion.'' Within this range the charge radius is smallest for {sup 24}Ne with N=14 corresponding to the closure of the neutron d{sub 5/2} shell, while it increases toward both neutron shell closures, N=8 and N=20. The general trend of the charge radii correlates well with the deformation effects which are known to be large for several neon isotopes. In the neutron-deficient isotopes, structural changes arise from the onset of proton-halo formation for {sup 17}Ne, shell closure in {sup 18}Ne, and clustering effects in {sup 20,21}Ne. On the neutron-rich side the transition to the island of inversion plays an important role, with the radii in the upper part of the sd shell confirming the weakening of the N=20 magic number. The results add new information to the radii systematics of light nuclei where data are scarce because of the small contribution of nuclear-size effects to the isotope shifts which are dominated by the finite-mass effect.

  14. NEON Citizen Science: Planning and Prototyping

    NASA Astrophysics Data System (ADS)

    Newman, S. J.; Henderson, S.; Gardiner, L. S.; Ward, D.; Gram, W.

    2011-12-01

    The National Ecological Observatory Network (NEON) will be a national resource for ecological research and education. NEON citizen science projects are being designed to increase awareness and educate citizen scientists about the impacts of climate change, land-use change, and invasive species on continental-scale ecological processes as well as expand NEON data collection capacity by enabling laypersons to collect geographically distributed data. The citizen science area of the NEON web portal will enable citizen scientists to collect, contribute, interpret, and visualize scientific data, as well as access training modules, collection protocols and targeted learning experiences related to citizen science project topics. For NEON, citizen science projects are a means for interested people to interact with and contribute to NEON science. Investigations at vast spatial and temporal scales often require rapid acquisition of large amounts of data from a geographically distributed population of "human sensors." As a continental-scale ecological observatory, NEON is uniquely positioned to develop strategies to effectively integrate data collected by non-scientists into scientific databases. Ultimately, we plan to work collaboratively to transform the practice of science to include "citizens" or non-scientists in the process. Doing science is not limited to scientists, and breaking down the barriers between scientists and citizens will help people better understand the power of using science in their own decision making. In preparation for fully developing the NEON citizen science program, we are partnering with Project BudBurst (PBB), a citizen science project focused on monitoring plant phenology. The educational goals of PBB are to: (1) increase awareness of climate change, (2) educate citizen scientists about the impacts of climate change on plants and the environment, and (3) increase science literacy by engaging participants in the scientific process. Phenology was

  15. Demonstrating Fluorescence with Neon Paper and Plastic

    NASA Astrophysics Data System (ADS)

    Birriel, Jennifer J.; Roe, Clarissa

    2015-09-01

    Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and office supply stores. We also employ violet-blue and green laser pointers as excitation sources. We conclude with a brief discussion of neon pigments in terms of the "day glow" or "daylight fluorescence" phenomenon.

  16. Multistage Zeeman deceleration of metastable neon

    SciTech Connect

    Wiederkehr, Alex W.; Motsch, Michael; Hogan, Stephen D.; Andrist, Markus; Schmutz, Hansjuerg; Lambillotte, Bruno; Agner, Josef A.; Merkt, Frederic

    2011-12-07

    A supersonic beam of metastable neon atoms has been decelerated by exploiting the interaction between the magnetic moment of the atoms and time-dependent inhomogeneous magnetic fields in a multistage Zeeman decelerator. Using 91 deceleration solenoids, the atoms were decelerated from an initial velocity of 580 m/s to final velocities as low as 105 m/s, corresponding to a removal of more than 95% of their initial kinetic energy. The phase-space distribution of the cold, decelerated atoms was characterized by time-of-flight and imaging measurements, from which a temperature of 10 mK was obtained in the moving frame of the decelerated sample. In combination with particle-trajectory simulations, these measurements allowed the phase-space acceptance of the decelerator to be quantified. The degree of isotope separation that can be achieved by multistage Zeeman deceleration was also studied by performing experiments with pulse sequences generated for {sup 20}Ne and {sup 22}Ne.

  17. Solar helium and neon in the Earth

    NASA Technical Reports Server (NTRS)

    Honda, M.; Mcdougall, I.; Patterson, D. B.

    1994-01-01

    Neon isotopic compositions in mantle-derived samples commonly are enriched in (20)Ne and (21)Ne relative to (22)Ne compared with atmospheric neon ((20)Ne/(22)Ne and (21)Ne/(22)Ne ratios in atmospheric neon are 9.8 and 0.029, respectively), together with significant primordial (3)He. Such results have been obtained on MORB's, intraplate plume-related oceanic island basalts, backarc basin basalts, mantle xenoliths, ancient diamonds and CO2 well gases (e.g., 1 - 8). The highest (20)Ne/(22)Ne ratio observed in MORB glasses (= 13.6 plus or minus 1.3 is close to the solar value (= 13.6, as observed in solar wind). In order to explain the enrichment of (20)Ne and (21)Ne relative to atmospheric neon for samples derived from the mantle, it is necessary to postulate the presence of at least two distinct non-atmospheric components. The two most likely candidates are solar and nucleogenic ((20)Ne/(22)Ne solar = 13.6 (21)Ne/(22)Ne solar = 0.032, (20)Ne/(22)Ne nucleogenic = 2.5 and (21)Ne/(22)Ne nucleogenic = 32). This is because solar neon is the only known component with a (20)Ne/(22)Ne ratio greater than both the atmospheric value and that observed in samples derived from the mantle. Nucleogenic neon is well known to elevate (21)Ne/(22)Ne ratios. Neon isotopic signatures observed in mantle-derived samples can be accounted for by mixing of the three neon end members: solar, nucleogenic and atmospheric.

  18. Solar helium and neon in the Earth

    NASA Technical Reports Server (NTRS)

    Honda, M.; Mcdougall, I.; Patterson, D. B.

    1994-01-01

    Neon isotopic compositions in mantle-derived samples commonly are enriched in (20)Ne and (21)Ne relative to (22)Ne compared with atmospheric neon ((20)Ne/(22)Ne and (21)Ne/(22)Ne ratios in atmospheric neon are 9.8 and 0.029, respectively), together with significant primordial (3)He. Such results have been obtained on MORB's, intraplate plume-related oceanic island basalts, backarc basin basalts, mantle xenoliths, ancient diamonds and CO2 well gases (e.g., 1 - 8). The highest (20)Ne/(22)Ne ratio observed in MORB glasses (= 13.6 plus or minus 1.3 is close to the solar value (= 13.6, as observed in solar wind). In order to explain the enrichment of (20)Ne and (21)Ne relative to atmospheric neon for samples derived from the mantle, it is necessary to postulate the presence of at least two distinct non-atmospheric components. The two most likely candidates are solar and nucleogenic ((20)Ne/(22)Ne solar = 13.6 (21)Ne/(22)Ne solar = 0.032, (20)Ne/(22)Ne nucleogenic = 2.5 and (21)Ne/(22)Ne nucleogenic = 32). This is because solar neon is the only known component with a (20)Ne/(22)Ne ratio greater than both the atmospheric value and that observed in samples derived from the mantle. Nucleogenic neon is well known to elevate (21)Ne/(22)Ne ratios. Neon isotopic signatures observed in mantle-derived samples can be accounted for by mixing of the three neon end members: solar, nucleogenic and atmospheric.

  19. Capturing Neon -- The First Experimental Structure of Neon Trapped Within a Metal-Organic Environment

    SciTech Connect

    Wood, Peter A.; Sarjeant, Amy A.; Yakovenko, Andrey A.; Ward, Suzanna C.; Groom, Colin R.

    2016-01-01

    Despite being the fifth most abundant element in the atmosphere, neon has never been observed in an organic or metal-organic environment. This study shows the adsorption of this highly unreactive element within such an environment and reveals the first crystallographic observation of an interaction between neon and a transition metal.

  20. Capturing neon - the first experimental structure of neon trapped within a metal-organic environment.

    PubMed

    Wood, Peter A; Sarjeant, Amy A; Yakovenko, Andrey A; Ward, Suzanna C; Groom, Colin R

    2016-08-21

    Despite being the fifth most abundant element in the atmosphere, neon has never been observed in an organic or metal-organic environment. This study shows the adsorption of this highly unreactive element within such an environment and reveals the first crystallographic observation of an interaction between neon and a transition metal.

  1. NEON Citizen Science: Planning and Prototyping (Invited)

    NASA Astrophysics Data System (ADS)

    Gram, W.

    2010-12-01

    The National Ecological Observatory Network (NEON) will be a national resource for ecological research and education. NEON citizen science projects are being designed to increase awareness and educate citizen scientists about the impacts of climate change, land-use change, and invasive species on continental-scale ecological processes as well as expand NEON data collection capacity by enabling laypersons to collect geographically distributed data. The citizen science area of the NEON web portal will enable citizen scientists to collect, contribute, interpret, and visualize scientific data, as well as access training modules, collection protocols and targeted learning experiences related to citizen science project topics. For NEON, citizen science projects are a means for interested people to interact with and contribute to NEON science. Investigations at vast spatial and temporal scales often require rapid acquisition of large amounts of data from a geographically distributed population of “human sensors.” As a continental-scale ecological observatory, NEON is uniquely positioned to develop strategies to effectively integrate data collected by non-scientists into scientific databases. Ultimately, we plan to work collaboratively to transform the practice of science to include “citizens” or non-scientists in the process. Doing science is not limited to scientists, and breaking down the barriers between scientists and citizens will help people better understand the power of using science in their own decision making. In preparation for fully developing the NEON citizen science program, we are partnering with Project BudBurst (PBB), a citizen science project focused on monitoring plant phenology. The educational goals of PBB are to: (1) increase awareness of climate change, (2) educate citizen scientists about the impacts of climate change on plants and the environment, and (3) increase science literacy by engaging participants in the scientific process

  2. Isoelectronic analogues of PN: Remarkably stable multiply charged cations

    SciTech Connect

    Wong, Ming Wah; Radom, L. )

    1990-01-25

    The structures and stabilities of PN and its 27 isoelectronic analogues, CS, SiO, BCl, AlF, BeAr, MgNe, Sn{sup +}, PO{sup +}, CCl{sup +}, SiF{sup +}, BAr{sup +}, AlNe{sup +}, SO{sup 2+}, NCl{sup 2+}, PF{sup 2+}, CAr{sup 2+}, SiNe{sup 2+}, OCl{sup 3+}, SF{sup 3+}, NAr{sup 3+}, PNe{sup 3+}, FCl{sup 4+}, OAr{sup 4+}, SNe{sup 4+}, FAr{sup 5+}, ClNe{sup 5+}, and ArNe{sup 6+}, have been examined by ab initio molecular orbital theory. The CASSCF/6-311G(MC)(d) level was used to determine the ground-state potential energy curves and spectroscopic constants for the 28 diatomic systems. Equilibrium structures were also obtained with the 6-311G(MC)(d) basis set at the MP3 and ST4CCD levels, and dissociation energies were determined at the MP4/6-311 + G(MC)(2df) and MP4/6-311 + G(MC)(3d2f) levels. For the neutral and monocation analogues of PN, the calculated equilibrium geometries (at MP3/6-311G(MC)(d)) and dissociation energies (at MP4/6-311 + G(MC)(3d2f)) are in very good agreement with available experimental values. All the dication analogues of PN, namely, SO{sup 2+}, NCl{sup 2+}, PF{sup 2+}, CAr{sup 2+}, and SiNe{sup 2+}, are predicted to be experimentally observable species. Of these, the SO{sup 2+}, NCl{sup 2+}, and CAr{sup 2+} dications are calculated to be kinetically stable species, with large barriers associated with the exothermic charge-separation reactions, while the PF{sup 2+} and SiNe{sup 2+} dications are predicted not only to be kinetically stable but also to be thermodynamically stable species.

  3. Helium and Neon in Comets

    NASA Technical Reports Server (NTRS)

    Jewitt, David

    1996-01-01

    Two comets were observed with EUVE in late 1994. Both comet Mueller and comet Borrelly are short-period comets having well established orbital elements and accurate ephemerides. Spectra of 40 ksec were taken of each. No evidence for emission lines from either Helium or Neon was detected. We calculated limits on the production rates of these atoms (relative to solar) assuming a standard isotropic outflow model, with a gas streaming speed of 1 km/s. The 3-sigma (99.7% confidence) limits (1/100,000 for He, 0.8 for Ne) are based on a conservative estimate of the noise in the EUVE spectra. They are also weakly dependent on the precise pointing and tracking of the EUVE field of view relative to the comet during the integrations. These limits are consistent with ice formation temperatures T greater than or equal to 30 K, as judged from the gas trapping experiments of Bar-Nun. For comparison, the solar abundances of these elements are He/O = 110, Ne/O = 1/16. Neither limit was as constraining as we had initially hoped, mainly because comets Mueller and Borrelly were intrinsically less active than anticipated.

  4. NEON Airborne Remote Sensing of Terrestrial Ecosystems

    NASA Astrophysics Data System (ADS)

    Kampe, T. U.; Leisso, N.; Krause, K.; Karpowicz, B. M.

    2012-12-01

    The National Ecological Observatory Network (NEON) is the continental-scale research platform that will collect information on ecosystems across the United States to advance our understanding and ability to forecast environmental change at the continental scale. One of NEON's observing systems, the Airborne Observation Platform (AOP), will fly an instrument suite consisting of a high-fidelity visible-to-shortwave infrared imaging spectrometer, a full waveform small footprint LiDAR, and a high-resolution digital camera on a low-altitude aircraft platform. NEON AOP is focused on acquiring data on several terrestrial Essential Climate Variables including bioclimate, biodiversity, biogeochemistry, and land use products. These variables are collected throughout a network of 60 sites across the Continental United States, Alaska, Hawaii and Puerto Rico via ground-based and airborne measurements. Airborne remote sensing plays a critical role by providing measurements at the scale of individual shrubs and larger plants over hundreds of square kilometers. The NEON AOP plays the role of bridging the spatial scales from that of individual organisms and stands to the scale of satellite-based remote sensing. NEON is building 3 airborne systems to facilitate the routine coverage of NEON sites and provide the capacity to respond to investigator requests for specific projects. The first NEON imaging spectrometer, a next-generation VSWIR instrument, was recently delivered to NEON by JPL. This instrument has been integrated with a small-footprint waveform LiDAR on the first NEON airborne platform (AOP-1). A series of AOP-1 test flights were conducted during the first year of NEON's construction phase. The goal of these flights was to test out instrument functionality and performance, exercise remote sensing collection protocols, and provide provisional data for algorithm and data product validation. These test flights focused the following questions: What is the optimal remote

  5. Superatom spectroscopy and the electronic state correlation between elements and isoelectronic molecular counterparts.

    PubMed

    Peppernick, Samuel J; Gunaratne, K D Dasitha; Castleman, A W

    2010-01-19

    Detailed in the present investigation are results pertaining to the photoelectron spectroscopy of negatively charged atomic ions and their isoelectronic molecular counterparts. Experiments utilizing the photoelectron imaging technique are performed on the negative ions of the group 10 noble metal block (i.e. Ni-, Pd-, and Pt-) of the periodic table at a photon energy of 2.33 eV (532 nm). The accessible electronic transitions, term energies, and orbital angular momentum components of the bound electronic states in the atom are then compared with photoelectron images collected for isoelectronic early transition metal heterogeneous diatomic molecules, M-X- (M = Ti,Zr,W; X = O or C). A superposition principle connecting the spectroscopy between the atomic and molecular species is observed, wherein the electronic structure of the diatomic is observed to mimic that present in the isoelectronic atom. The molecular ions studied in this work, TiO-, ZrO-, and WC- can then be interpreted as possessing superatomic electronic structures reminiscent of the isoelectronic elements appearing on the periodic table, thereby quantifying the superatom concept.

  6. 21 CFR 868.1670 - Neon gas analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Neon gas analyzer. 868.1670 Section 868.1670 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1670 Neon gas analyzer. (a) Identification. A neon...

  7. The First NEON School in La Silla

    NASA Astrophysics Data System (ADS)

    Dennefeld, M.; Melo, C.; Selman, F.

    2016-06-01

    The NEON Observing Schools have long provided PhD students with practical experience in the preparation, execution and reduction of astronomical observations, primarily at northern observatories. The NEON School was held in Chile for the first time, with observations being conducted at La Silla. The school was attended by 20 students, all from South America, and observations were performed with two telescopes, including the New Technology Telescope. A brief description of the school is presented and the observing projects and their results are described.

  8. Neon diffusion kinetics and implications for cosmogenic neon paleothermometry in feldspars

    NASA Astrophysics Data System (ADS)

    Tremblay, Marissa M.; Shuster, David L.; Balco, Greg; Cassata, William S.

    2017-05-01

    Observations of cosmogenic neon concentrations in feldspars can potentially be used to constrain the surface exposure duration or surface temperature history of geologic samples. The applicability of cosmogenic neon to either application depends on the temperature-dependent diffusivity of neon isotopes. In this work, we investigate the kinetics of neon diffusion in feldspars of different compositions and geologic origins through stepwise degassing experiments on single, proton-irradiated crystals. To understand the potential causes of complex diffusion behavior that is sometimes manifest as nonlinearity in Arrhenius plots, we compare our results to argon stepwise degassing experiments previously conducted on the same feldspars. Many of the feldspars we studied exhibit linear Arrhenius behavior for neon whereas argon degassing from the same feldspars did not. This suggests that nonlinear behavior in argon experiments is an artifact of structural changes during laboratory heating. However, other feldspars that we examined exhibit nonlinear Arrhenius behavior for neon diffusion at temperatures far below any known structural changes, which suggests that some preexisting material property is responsible for the complex behavior. In general, neon diffusion kinetics vary widely across the different feldspars studied, with estimated activation energies (Ea) ranging from 83.3 to 110.7 kJ/mol and apparent pre-exponential factors (D0) spanning three orders of magnitude from 2.4 × 10-3 to 8.9 × 10-1 cm2 s-1. As a consequence of this variability, the ability to reconstruct temperatures or exposure durations from cosmogenic neon abundances will depend on both the specific feldspar and the surface temperature conditions at the geologic site of interest.

  9. Excited states of boron isoelectronic series from explicitly correlated wave functions.

    PubMed

    Gálvez, F J; Buendía, E; Sarsa, A

    2005-04-15

    The ground state and some low-lying excited states arising from the 1s2 2s2p2 configuration of the boron isoelectronic series are studied starting from explicitly correlated multideterminant wave functions. One- and two-body densities in position space have been calculated and different expectation values such as , , , , , and , where r, r12, and R stand for the electron-nucleus, interelectronic, and two electron center of mass coordinates, respectively, have been obtained. The energetic ordering of the excited states and the fulfillment of the Hund's rules is analyzed systematically along the isoelectronic series in terms of the electron-electron and electron-nucleus potential energies. The effects of electronic correlations have been systematically studied by comparing the correlated results with the corresponding noncorrelated ones. All the calculations have been done by using the variational Monte Carlo method.

  10. Isoelectronic Tungsten Doping in Monolayer MoSe2 for Carrier Type Modulation.

    PubMed

    Li, Xufan; Lin, Ming-Wei; Basile, Leonardo; Hus, Saban M; Puretzky, Alexander A; Lee, Jaekwang; Kuo, Yen-Chien; Chang, Lo-Yueh; Wang, Kai; Idrobo, Juan C; Li, An-Ping; Chen, Chia-Hao; Rouleau, Christopher M; Geohegan, David B; Xiao, Kai

    2016-10-01

    Carrier-type modulation is demonstrated in 2D transition metal dichalcogenides as n-type monolayer MoSe2 is converted to nondegenerate p-type monolayer Mo1-x Wx Se2 through isoelectronic doping. Although the alloys are mesoscopically uniform, the p-type conduction in monolayer Mo1-x Wx Se2 appears to originate from the upshift of the valenceband maximum toward the Fermi level at highly localized "W-rich" regions in the lattice.

  11. Photoionization of isoelectronic ions: Mg{sup +} and Al{sup 2+}

    SciTech Connect

    Aguilar, A.; West, J.B.; Phaneuf, R.A.; Brooks, R. L.; Folkmann, F.; Kjeldsen, H.; Bozek, J.D.; Schlachter, A.S.; Cisneros, C.

    2003-01-01

    High-resolution measurements of the photoionization cross sections of the Na-isoelectronic ions Mg{sup +} and Al{sup 2+} are presented, to be compared with earlier measurements in which structure in the most prominent peaks was unresolved. These measurements have been normalized to the earlier ones in order to provide values of the oscillator strengths of the newly resolved peaks, and comparison is made with multiconfiguration Hartree-Fock calculations.

  12. Rogue Mantle Helium and Neon

    NASA Astrophysics Data System (ADS)

    Albarede, F.

    2007-12-01

    mid- ocean ridges, the characteristic times of melt extraction in each of these two environments are 10,000 y and 1 My, respectively, and the maximum thickness of refractory layers contributing their He to the magmas are 10 m and 100 m, respectively. The difference in 3He/4He ratios of ocean-island and mid-ocean ridge basalts and the preservation of solar neon are ascribed to the reservoirs rocks being stretched to a different extent during melting. Old fragments of oceanic lithosphere, and possibly cumulates from the magma ocean, rather than primordial mantle 'nuggets', should host most of the primordial He and Ne presently observed in oceanic basalts. Helium with high 3He/4He ratios may contain a component of primordial origin, but not necessarily reflect the reservoir in which it has been residing for most of the Earth's history.

  13. Increasing the sensitivity of LXe TPCs to dark matter by doping with helium or neon

    DOE PAGES

    Lippincott, W. Hugh; Alexander, Thomas R.; Hime, Andrew

    2017-02-03

    Next generation liquid xenon TPCs are poised to increase our sensitivity to dark matter by two orders of magnitude over a wide range of possible dark matter candidates. This proceedings describes an idea to expand the reach and flexibility of such detectors even further, by adding helium and neon to the xenon to enable searches for very light dark matter and combining high and low Z targets in the same detector. Adding helium or neon to LXe-TPCs has many advantages. First, the helium or neon target benefits from the excellent self-shielding provided by a large liquid xenon detector. Second, themore » same instrumentation, PMTs, and data acquisition can be used. Third, light nuclei are more robust to the systematic uncertainties that affect light WIMP searches. Fourth, helium and neon recoils will likely produce larger signals in liquid xenon than xenon recoils, achieving lower energy thresholds, and further increasing the sensitivity to light WIMPs. Finally, by adding He/Ne in sequence after a Xe-only run, the source of any observed signal can be isolated.« less

  14. Enhanced Photocatalytic Water Splitting in a C2 N Monolayer by C-Site Isoelectronic Substitution.

    PubMed

    Kishore, M R Ashwin; Ravindran, P

    2017-06-20

    Two-dimensional (2D) semiconductors have shown great promise as efficient photocatalysts for water splitting. Tailoring the band gap and band edge positions are the most crucial steps to further improve the photocatalytic activity of 2D materials. Here, we report an improved photocatalytic water splitting activity in a C2 N monolayer by isoelectronic substitutions at the C-site, based on density functional calculations. Our optical calculations show that the isoelectronic substitutions significantly reduce the band gap of the C2 N monolayer and thus strongly enhance the absorption of visible light, which is consistent with the observed redshift in the optical absorption spectra. Based on the HSE06 functional, the calculated band edge positions of C2-x Six N and C2-x Gex N monolayers are even more favorable than the pristine C2 N monolayer for the overall photocatalytic activity. On the other hand, for the C2-x Snx N monolayer, the conduction band minima is more positive than the oxygen reduction potential and, hence, Sn substitution in C2 N is unfavorable for the water decomposition reaction. In addition, the isoelectronic substitutions improve the separation of e(-) -h(+) pairs, which, in turn, suppress the recombination rate, thereby leading to enhanced photocatalytic activity in this material. Our results imply that Si-, and Ge-substituted C2 N monolayers will be a promising visible-light photocatalysts for water splitting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. ASA's Chandra Neon Discovery Solves Solar Paradox

    NASA Astrophysics Data System (ADS)

    2005-07-01

    NASA's Chandra X-ray Observatory survey of nearby sun-like stars suggests there is nearly three times more neon in the sun and local universe than previously believed. If true, this would solve a critical problem with understanding how the sun works. "We use the sun to test how well we understand stars and, to some extent, the rest of the universe," said Jeremy Drake of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "But in order to understand the sun, we need to know exactly what it is made of," he added. It is not well known how much neon the sun contains. This is critical information for creating theoretical models of the sun. Neon atoms, along with carbon, oxygen and nitrogen, play an important role in how quickly energy flows from nuclear reactions in the sun's core to its edge, where it then radiates into space. Chandra X-ray Spectrum of II Pegasi Chandra X-ray Spectrum of II Pegasi The rate of this energy flow determines the location and size of a crucial stellar region called the convection zone. The zone extends from near the sun's surface inward approximately 125,000 miles. The zone is where the gas undergoes a rolling, convective motion much like the unstable air in a thunderstorm. "This turbulent gas has an extremely important job, because nearly all of the energy emitted at the surface of the sun is transported there by convection," Drake said. The accepted amount of neon in the sun has led to a paradox. The predicted location and size of the solar convection zone disagree with those deduced from solar oscillations. Solar oscillations is a technique astronomers previously relied on to probe the sun's interior. Several scientists have noted the problem could be fixed if the abundance of neon is in fact about three times larger than currently accepted. Attempts to measure the precise amount of neon in the Sun have been frustrated by a quirk of nature; neon atoms in the Sun give off no signatures in visible light. However, in a gas

  16. The NEON Soil Archive - A community resource

    NASA Astrophysics Data System (ADS)

    Ayres, E.

    2013-12-01

    The National Ecological Observatory Network (NEON) is a 30-year National Science Foundation-funded facility for understanding and forecasting the impacts of climate change, land use change, and invasive species on aspects of continental-scale ecology such as biodiversity, biogeochemistry, infectious diseases, and ecohydrology. NEON will measure a wide range of properties at 60 terrestrial and 36 aquatic sites throughout the US using in situ sensors, sample collection/lab analysis, and remote sensing, and all data will be made freely available. The Observatory is currently under construction and will be fully operational by 2017, however, limited data collection and release will begin in 2013. In addition, NEON is archiving large numbers of samples, including surface soils (top ~30 cm) collected from locations across each site, and soils collected by horizon to 2 m deep from a single soil pit at each site. Here I present information about the latter, focusing on sampling and processing, metadata, and currently available samples. At each terrestrial site the soil pit is dug in the locally dominant soil type and soil is collected by horizon, mixed, and ~4-8 liters soil is sent for processing. Soil samples are air-dried and sieved (mineral soil) or air-dried (organic soil) and 1.2 kg is split between 4 glass jars for archiving (protocol available upon request). To date 15 soil pits have been sampled, representing 7 soil orders, and soils from 110 horizons have been archived or are being processed. Metadata associated with each archive sample include a soil profile description, photos, and soil properties (total C, N, S, Al, Ca, Fe, K, Mg, Mn, Na, P, Si, Sr, Ti, Zr, bulk density, pH, and texture). The procedure for requesting samples from the archive is under development and I encourage scientists to use the archive in their future research. Collecting and processing samples for the NEON Soil Archive

  17. Binary collision model for neon Auger spectra from neon ion bombardment of the aluminum surface

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.

    1986-01-01

    A model is developed to account for the angle-resolved Auger spectra from neon ion bombardment of the aluminum surface recently obtained by Pepper and Aron. The neon is assumed to be excited in a single asymmetric neon-aluminum-collision and scattered back into the vacuum where it emits an Auger electron. The velocity of the Auger electron acquires a Doppler shift by virtue of the emission from a moving source. The dependence of the Auger peak shape and energy on the incident ion energy, angle of incidence and on the angle of Auger electron emission with respect to the surface is presented. Satisfactory agreement with the angle resolved experimental observations is obtained. The dependence of the angle-integrated Auger yield on the incident ion energy and angle of incidence is also obtained and shown to be in satisfactory agreement with available experimental evidence.

  18. Suppression of Defects and Deep Levels Using Isoelectronic Tungsten Substitution in Monolayer MoSe2

    DOE PAGES

    Li, Xufan; Puretzky, Alexander A.; Sang, Xiahan; ...

    2017-05-18

    Chemical vapor deposition (CVD) is one of the most promising, scalable synthetic techniques to enable large-area synthesis of two-dimensional (2D) transition metal dichalcogenides (TMDs) for the realization of next generation optoelectronic devices. However, defects formed during the CVD growth process currently limit the quality and electronic properties of 2D TMDs. Effective synthesis and processing strategies to suppress defects and enhance the quality of 2D TMDs are urgently needed. In this work, isoelectrnic doping to produce stable alloy is presented as a new strategy to suppress defects and enhance photoluminescence (PL) in CVD-grown TMD monolayers. The random, isoelectronic substitution of Wmore » atoms for Mo atoms in CVD-grown monolayers of Mo1-xWxSe2 (02 monolayers. The resultant decrease in defect-medicated non-radiative recombination in the Mo0.82W0.18Se2 monolayers yielded ~10 times more intense PL and extended the carrier lifetime by a factor of 3 compared to pristine CVD-grown MoSe2 monolayers grown under similar conditions. Low temperatures (4 125 K) PL from defect-related localized states confirms theoretical predictions that isoelectronic W alloying should suppress deep levels in MoSe2, showing that the defect levels in Mo1-xWxSe2 monolayers are higher in energy and quenched more quickly than in MoSe2. Isoelectronic substitution therefore appears to be a promising synthetic method to control the heterogeneity of 2D TMDs to realize the scalable production of high performance optoelectronic and electronic devices.« less

  19. Paramagnetic closed-shell molecules: the isoelectronic series CH , BH and BeH-

    NASA Astrophysics Data System (ADS)

    Fowler, P. W.; Steiner, E.

    Coupled Hartree-Fock calculations predict CH+, like its isoelectronic analogue BH, to be paramagnetic. The calculated magnetizability has components χ∥(CH+) = - 1·44 and χ⊥(CH+) = + 10·54 a.u. with a mean value χ(CH+) = + 6·55 a.u. (5·17 × 10-28 J T-2). Predicted nuclear shieldings are σ(C) = - 1250 ppm and σ(H) = + 34·1 ppm. The isolated BeH- anion is predicted to lie on the diamagnetic/paramagnetic borderline, but when placed in a crystal lattice is likely to be weakly diamagnetic.

  20. Dietary protein source and level alters growth in neon tetras.

    USDA-ARS?s Scientific Manuscript database

    Nutritional studies for aquarium fish like the neon tetra are sparse in comparison with those for food fish. To determine the optimum dietary protein level and source for growth of neon tetras, diets were formulated to contain 25, 35, 45 and 55% dietary protein from either marine animal protein or ...

  1. NEON terrestrial field observations: designing continental scale, standardized sampling

    Treesearch

    R. H. Kao; C.M. Gibson; R. E. Gallery; C. L. Meier; D. T. Barnett; K. M. Docherty; K. K. Blevins; P. D. Travers; E. Azuaje; Y. P. Springer; K. M. Thibault; V. J. McKenzie; M. Keller; L. F. Alves; E. L. S. Hinckley; J. Parnell; D. Schimel

    2012-01-01

    Rapid changes in climate and land use and the resulting shifts in species distributions and ecosystem functions have motivated the development of the National Ecological Observatory Network (NEON). Integrating across spatial scales from ground sampling to remote sensing, NEON will provide data for users to address ecological responses to changes in climate, land use,...

  2. On the systematics of line ratios along the helium isoelectronic sequence

    NASA Astrophysics Data System (ADS)

    Pradhan, A. K.

    1982-12-01

    Temperature and change dependence of the line ratios involving the forbidden, intercombination, and the resonance lines is investigated for helium-like ions of C, O, Ne, Si, S, Ca, and Fe. Systematic variations are found and should facilitate the interpretation of observed data. Calculations are carried out using more accurate atomic data than earlier works resulting in significant differences. A few recent observations from laboratory and astrophysical plasmas are discussed.

  3. Third-order many-body perturbation theory calculations for the beryllium and magnesium isoelectronic sequences

    SciTech Connect

    Ho, H. C.; Johnson, W. R.; Blundell, S. A.; Safronova, M. S.

    2006-08-15

    Third-order relativistic many-body perturbation theory (MBPT) is applied to obtain energies of ions with two valence electrons in the no virtual-pair approximation (NVPA). A total of 302 third-order Goldstone diagrams are organized into 12 one-body and 23 two-body terms. Only third-order two-body terms and diagrams are presented in this paper, owing to the fact that the one-body terms are identical to the previously studied third-order terms in monovalent ions. Dominant classes of diagrams are identified. The model potential is the Dirac-Hartree-Fock potential V{sup N-2}, and B-spline basis functions in a cavity of finite radius are employed in the numerical calculations. The Breit interaction is taken into account through the second order of perturbation theory, and the lowest-order Lamb shift is also evaluated. Sample calculations are performed for berylliumlike ions with Z=4-7, and for the magnesiumlike ion P IV. The third-order excitation energies are in excellent agreement with measurement with an accuracy at 0.2% level for the cases considered. Comparisons are made with second-order MBPT results, and with other calculations. The third-order energy correction is shown to be significant, improving the previous second-order calculations by an order of magnitude.

  4. VizieR Online Data Catalog: Sulphur ions iso-electronic sequence (Liang+, 2011)

    NASA Astrophysics Data System (ADS)

    Liang, G. Y.; Badnell, N. R.; Zhao, G.; Zhong, J. Y.; Wang, F. L.

    2011-08-01

    The effective collision strengths at 13 temperatures ranging from 2x102(q+1)2 to 2x106(q+1)2K, where q is the residual charge of ions, have been calculated using the ICFT R-matrix method. The data format adopts ADAS adf04 format, see the file at website http://www.adas.ac.uk/man/appxa-04.pdf Additionally, tables of level energies for S10+ and S11+, along with other predictions are available in this online material. (6 data files).

  5. Energy levels and transition rates for the boron isoelectronic sequence: Si X, Ti XVIII - Cu XXV

    NASA Astrophysics Data System (ADS)

    Jönsson, P.; Ekman, J.; Gustafsson, S.; Hartman, H.; Karlsson, L. B.; du Rietz, R.; Gaigalas, G.; Godefroid, M. R.; Froese Fischer, C.

    2013-11-01

    Relativistic configuration interaction (RCI) calculations are performed for 291 states belonging to the configurations 1s22s22p, 1s22s2p2, 1s22p3, 1s22s23l, 1s22s2p3l, 1s22p23l, 1s22s24l', 1s22s2p4l', and 1s22p24l' (l = 0,1,2 and l' = 0,1,2,3) in boron-like ions Si X and Ti XVIII to Cu XXV. Electron correlation effects are represented in the wave functions by large configuration state function (CSF) expansions. States are transformed from jj-coupling to LS-coupling, and the LS-percentage compositions are used for labeling the levels. Radiative electric dipole transition rates are given for all ions, leading to massive data sets. Calculated energy levels are compared with other theoretical predictions and crosschecked against the Chianti database, NIST recommended values, and other observations. The accuracy of the calculations are high enough to facilitate the identification of observed spectral lines. Research supported in part by the Swedish Research council and the Swedish Institute. Part of this work was supported by the Communauté française of Belgium, the Belgian National Fund for Scientific Research (FRFC/IISN Convention) and by the IUAP-Belgian State Science Policy (BriX network P7/12).Tables of energy levels and transition rates (Tables 3-19) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A100

  6. Excitation energies, oscillator strengths, and lifetimes of levels along the gold isoelectronic sequence

    SciTech Connect

    Safronova, U.I.; Johnson, W.R.

    2004-05-01

    Energies of ns{sub 1/2}(n=6-9), np{sub j}(n=6-8), nd{sub j}(n=6-7), and 5f{sub j} states in neutral Au and Au-like ions with nuclear charges Z=80-83 are calculated using relativistic many-body perturbation theory. Reduced matrix elements, oscillator strengths, transition rates and lifetimes are determined for the 30 possible nl{sub j}-n{sup '}l{sub j{sup '}}{sup '} electric-dipole transitions. Results for a limited number states, ns{sub 1/2}, np{sub j}(n=6-7) and 6d{sub j} are obtained in the relativistic single-double (SD) approximation, where single and double excitations of Dirac-Fock wave functions are included to all orders in perturbation theory. Using SD wave functions, accurate values are obtained for energies of the eight lowest states and for the fourteen possible electric-dipole matrix elements between these states. With the aid of the SD wave functions, we also determine transition rates and oscillator strengths for the fourteen transitions together with lifetimes of 6p{sub j}, 7p{sub j}, and 6d{sub j} levels. We investigate the hyperfine structure in Hg II and Tl III. The hyperfine A values are determined for 6s{sub 1/2} and 6p{sub j} states in {sup 199}Hg{sup +}, {sup 201}Hg{sup +}, and {sup 205}Tl{sup 2+} isotopes. These calculations provide a theoretical benchmark for comparison with experiment and theory.

  7. Excitation energies, oscillator strengths, and lifetimes of levels along the gold isoelectronic sequence

    NASA Astrophysics Data System (ADS)

    Safronova, U. I.; Johnson, W. R.

    2004-05-01

    Energies of n s1/2 ( n=6-9 ) , n pj ( n=6-8 ) , n dj ( n=6-7 ) , and 5 fj states in neutral Au and Au-like ions with nuclear charges Z=80 83 are calculated using relativistic many-body perturbation theory. Reduced matrix elements, oscillator strengths, transition rates and lifetimes are determined for the 30 possible n lj - n' l 'j' electric-dipole transitions. Results for a limited number states n s1/2 , n pj ( n=6 7 ) and 6 dj are obtained in the relativistic single-double (SD) approximation, where single and double excitations of Dirac-Fock wave functions are included to all orders in perturbation theory. Using SD wave functions, accurate values are obtained for energies of the eight lowest states and for the fourteen possible electric-dipole matrix elements between these states. With the aid of the SD wave functions, we also determine transition rates and oscillator strengths for the fourteen transitions together with lifetimes of 6 pj , 7 pj , and 6 dj levels. We investigate the hyperfine structure in Hg II and Tl III . The hyperfine A values are determined for 6 s1/2 and 6 pj states in 199 Hg+ , 201 Hg+ , and 205 Tl2+ isotopes. These calculations provide a theoretical benchmark for comparison with experiment and theory.

  8. 40 K Liquid Neon Energy Storage Unit

    NASA Astrophysics Data System (ADS)

    Martins, D.; Sousa, P. Borges de; Catarino, I.; Bonfait, G.

    A thermal Energy Storage Unit (ESU) could be used to attenuate inherent temperature fluctuations of a cold finger, either from a cryocooler working or due to suddenly incoming heat bursts. An ESU directly coupled to the cold source acts as a thermal buffer temporarily increasing its cooling capacity and providing a better thermal stability of the cold finger ("Power Booster mode"). The energy storage units presented here use an enthalpy reservoir based on the high latent heat of the liquid-vapour transition of neon in the temperature range 38 - 44 K to store up to 900 J, and that uses a 6 liters expansion volume at room temperature in order to work as a closed system. Experimental results in the power booster mode are described: in this case, the liquid neon cell was directly coupled to the cold finger of the working cryocooler, its volume (≈12 cm3) allowing it to store 450 J at around 40 K. 10 W heat bursts were applied, leading to liquid evaporation, with quite reduced temperature changes. The liquid neon reservoir can also work as a temporary cold source to be used after stopping the cryocooler, allowing for a vibration-free environment. In this case the enthalpy reservoir implemented (≈24 cm3) was linked to the cryocooler cold finger through a gas-gap heat switch for thermal coupling/decoupling of the cold finger. We show that, by controlling the enthalpy reservoir's pressure, 900 Jcan be stored at a constant temperature of 40 K as in a triple-point ESU.

  9. Neon photoionized plasma experiment at Z

    NASA Astrophysics Data System (ADS)

    Mayes, D. C.; Mancini, R. C.; Bailey, J. E.; Loisel, G. P.; Rochau, G. A.

    2016-10-01

    We discuss an experimental effort to study the atomic kinetics in neon photoionized plasmas via K-shell line absorption spectroscopy. The experiment employs the intense x-ray flux emitted at the collapse of a Z-pinch to heat and backlight a photoionized plasma contained within a cm-scale gas cell placed at various distances from the Z-pinch and filled with neon gas pressures in the range from 3.5 to 30 torr. The experimental platform affords an order of magnitude range in the ionization parameter characterizing the photoionized plasma from about 3 to 80 erg*cm/s. An x-ray crystal spectrometer capable of collecting both time-integrated and time-gated spectra is used to collect absorption spectra. A suite of IDL programs has been developed to process the experimental data to produce transmission spectra. The spectra show line absorption by several ionization stages of neon, including Be-, Li-, He-, and H-like ions. Analysis of these spectra yields ion areal-densities and charge state distributions, which can be compared with results from atomic kinetics codes. In addition, the electron temperature is extracted from level population ratios of nearby energy levels in Li- and Be-like ions, which can be used to test heating models of photoionized plasmas. This work was sponsored in part by the DOE National Nuclear Security Administration Grant DE-FG52-09NA29551, DOE Office of Science Grant DE-SC0014451, and the Z Facility Fundamental Science Program of SNL.

  10. Anomalous diffusion of isoelectronic antimony implant induced defects in GaAs-AlGaAs multiquantum well structures

    NASA Astrophysics Data System (ADS)

    Rao, E. V. K.; Krauz, Ph.; Thibierge, H.; Azoulay, R.; Vieu, C.

    1994-03-01

    We present here evidence on the deep diffusion of isoelectronic Sb implant induced defects in thick GaAs-AlGaAs multiquantum well structures (MQW) to depths as far as ˜30 times the implant projected range (Rp). This observation has been confirmed by performing low temperature photoluminescence depth scanning measurements and cross-sectional transmission electron microscopy (XTEM) analysis on room temperature Sb implanted thick MQW samples. An explanation based on the isoelectronic nature of Sb and its substitution on As site (SbAs) has been proposed to understand the anomalous diffusion of defects during implant and their contribution to Al/Ga disordering during post-implant annealing.

  11. Neon reduction program on Cymer ArF light sources

    NASA Astrophysics Data System (ADS)

    Kanawade, Dinesh; Roman, Yzzer; Cacouris, Ted; Thornes, Josh; O'Brien, Kevin

    2016-03-01

    In response to significant neon supply constraints, Cymer has responded with a multi-part plan to support its customers. Cymer's primary objective is to ensure that reliable system performance is maintained while minimizing gas consumption. Gas algorithms were optimized to ensure stable performance across all operating conditions. The Cymer neon support plan contains four elements: 1. Gas reduction program to reduce neon by >50% while maintaining existing performance levels and availability; 2. short-term containment solutions for immediate relief. 3. qualification of additional gas suppliers; and 4. long-term recycling/reclaim opportunity. The Cymer neon reduction program has shown excellent results as demonstrated through the comparison on standard gas use versus the new >50% reduced neon performance for ArF immersion light sources. Testing included stressful conditions such as repetition rate, duty cycle and energy target changes. No performance degradation has been observed over typical gas lives.

  12. Perceptual transparency in neon color spreading displays.

    PubMed

    Ekroll, Vebjørn; Faul, Franz

    2002-08-01

    In neon color spreading displays, both a color illusion and perceptual transparency can be seen. In this study, we investigated the color conditions for the perception of transparency in such displays. It was found that the data are very well accounted for by a generalization of Metelli's (1970) episcotister model of balanced perceptual transparency to tristimulus values. This additive model correctly predicted which combinations of colors would lead to optimal impressions of transparency. Color combinations deviating slightly from the additive model also looked transparent, but less convincingly so.

  13. Scattering of electrons from neon atoms

    NASA Technical Reports Server (NTRS)

    Dasgupta, A.; Bhatia, A. K.

    1984-01-01

    Scattering of electrons from neon atoms is investigated by the polarized-orbital method. The perturbed orbitals calculated with use of the Sternheimer approximation lead to the polarizability 2.803 a(0)-cube in fairly good agreement with the experimental value 2.66 a(0)-cube. Phase shifts for various partial waves are calculated in the exchange, exchange-adiabatic, and polarized-orbital approximations. They are compared with the previous results. The calculated elastic differential, total, and momentum-transfer cross sections are compared with the experimental results. The polarized-orbital approximation yields results which show general improvement over the exchange-adiabatic approximation.

  14. Diffusion of neon in white dwarf stars.

    PubMed

    Hughto, J; Schneider, A S; Horowitz, C J; Berry, D K

    2010-12-01

    Sedimentation of the neutron rich isotope 22Ne may be an important source of gravitational energy during the cooling of white dwarf stars. This depends on the diffusion constant for 22Ne in strongly coupled plasma mixtures. We calculate self-diffusion constants D(i) from molecular dynamics simulations of carbon, oxygen, and neon mixtures. We find that D(i) in a mixture does not differ greatly from earlier one component plasma results. For strong coupling (coulomb parameter Γ> few), D(i) has a modest dependence on the charge Z(i) of the ion species, D(i)∝Z(i)(-2/3). However, D(i) depends more strongly on Z(i) for weak coupling (smaller Γ). We conclude that the self-diffusion constant D(Ne) for 22Ne in carbon, oxygen, and neon plasma mixtures is accurately known so that uncertainties in D(Ne) should be unimportant for simulations of white dwarf cooling.

  15. Damage accumulation in neon implanted silicon

    SciTech Connect

    Oliviero, E.; Peripolli, S.; Amaral, L.; Fichtner, P. F. P.; Beaufort, M. F.; Barbot, J. F.; Donnelly, S. E.

    2006-08-15

    Damage accumulation in neon-implanted silicon with fluences ranging from 5x10{sup 14} to 5x10{sup 16} Ne cm{sup -2} has been studied in detail. As-implanted and annealed samples were investigated by Rutherford backscattering spectrometry under channeling conditions and by transmission electron microscopy in order to quantify and characterize the lattice damage. Wavelength dispersive spectrometry was used to obtain the relative neon content stored in the matrix. Implantation at room temperature leads to the amorphization of the silicon while a high density of nanosized bubbles is observed all along the ion distribution, forming a uniform and continuous layer for implantation temperatures higher than 250 deg.C. Clusters of interstitial defects are also present in the deeper part of the layer corresponding to the end of range of ions. After annealing, the samples implanted at temperatures below 250 deg.C present a polycrystalline structure with blisters at the surface while in the other samples coarsening of bubbles occurs and nanocavities are formed together with extended defects identified as (311) defects. The results are discussed in comparison to the case of helium-implanted silicon and in the light of radiation-enhanced diffusion.

  16. Isoelectronic x-ray spectroscopy to determine electron temperatures in long-scale-length inertial-confinement-fusion plasmas

    NASA Astrophysics Data System (ADS)

    Shepard, T. D.; Back, C. A.; Kalantar, D. H.; Kauffman, R. L.; Keane, C. J.; Klem, D. E.; Lasinski, B. F.; MacGowan, B. J.; Powers, L. V.; Suter, L. J.; Turner, R. E.; Failor, B. H.; Hsing, W. W.

    1996-05-01

    We have successfully employed isoelectronic line ratios to measure the electron temperature in gas-filled Hohlraum targets and gas bags shot with the Nova laser. These targets produce millimeter-scale-length plasmas with electron density Ne~1021 cm-3 and electron temperature Te~3 keV. The Hohlraum targets can also produce radiation temperature exceeding 200 eV. Isoelectronic line ratios are well suited to this measurement because they are relatively insensitive to radiation field effects in Hohlraum targets, opacity, transients, and variations in electron density compared to conventional line ratios. We survey the properties of isoelectronic line ratios formed from ratios of n-to-1 resonance transitions in heliumlike Cr to the same transitions in Ti and compare with conventional ratios of n-to-1 transitions in hydrogenlike Ti to the corresponding transitions in heliumlike Ti, concentrating on plasma parameter ranges of interest to the Nova experiments. We also consider the same ratios using K and Cl. Atomic kinetics are treated using collisional-radiative models and experimental data are analyzed with the aid of radiation-hydrodynamics calculations. When we apply isoelectronic techniques to the Nova experimental data, we find that the targets have electron temperatures of at least 3 keV.

  17. SIGN, a WIMP detector based on high pressure gaseous neon

    NASA Astrophysics Data System (ADS)

    White, J. T.; Gao, J.; Maxin, J.; Miller, J.; Salinas, G.; Wang, H.

    A new WIMP detector concept based on the measurement of Scintillation and Ionization in Gaseous Neon (SIGN) is presented. The detector employs room temperature gaseous neon at a pressure of ≥100 bars as the WIMP target. The ionization is readout using either charge gain or electrofluorescence or both in a modified cylindrical proportional chamber geometry. The primary scintillation is detected by placing a CsI photocathode on the inside wall of the cylindrical chamber. The neon is doped with xenon (≤0.5%) for signal enhancement. Theoretical considerations suggest that the measurement of both scintillation and ionization will provide discrimination between nuclear and electron recoils in this gas mixture.

  18. Neon colour spreading with and without its figural prerequisites.

    PubMed

    Bressan, P

    1993-01-01

    Neon colour spreading has been shown to disappear if certain figural conditions are not met. Evidence is presented which suggests that these conditions are only incidentally related to the neon spreading effect; in particular, that they can be violated as long as the structure remains compatible with the interpretation of a transparent surface. It is proposed that neon spreading and classical colour assimilation share the same basic mechanism, and that the peculiar perceptual attributes of the former derive from the perceptual scissioning of ordinary assimilation colour. This process is identical to that occurring with nonillusory colours in phenomenal transparency.

  19. The prospects of a subnanometer focused neon ion beam.

    PubMed

    Rahman, F H M; McVey, Shawn; Farkas, Louis; Notte, John A; Tan, Shida; Livengood, Richard H

    2012-01-01

    The success of the helium ion microscope has encouraged extensions of this technology to produce beams of other ion species. A review of the various candidate ion beams and their technical prospects suggest that a neon beam might be the most readily achieved. Such a neon beam would provide a sputtering yield that exceeds helium by an order of magnitude while still offering a theoretical probe size less than 1-nm. This article outlines the motivation for a neon gas field ion source, the expected performance through simulations, and provides an update of our experimental progress. © Wiley Periodicals, Inc.

  20. Comprehensive Testing of a Neon Cryogenic Capillary Pumped Loop

    NASA Technical Reports Server (NTRS)

    Kobel, Mark C.; Ku, Jentung; Obenschain, Arthur F. (Technical Monitor)

    2001-01-01

    This paper describes a comprehensive test program of a cryogenic capillary pumped loop (CCPL) using neon as the working fluid in the temperature range between 30 K and 40 K. The test article was originally designed to be used with nitrogen in the 70 K to 100 K temperature range, and was refurbished for testing with neon. Tests performed included start up from a supercritical state, power cycle, sink temperature cycle, heat transport limit, low power limit, reservoir set point change and long duration operation. The neon CCPL has demonstrated excellent performance under various conditions.

  1. From Saturated BN Compounds to Isoelectronic BN/CC Counterparts: An Insight from Computational Perspective.

    PubMed

    Sagan, Filip; Piękoś, Łukasz; Andrzejak, Marcin; Mitoraj, Mariusz Paweł

    2015-10-19

    In the present study, the inorganic analogues of alkanes as well as their isoelectronic BN/CC counterparts that bridge the gap between organic and inorganic chemistry are comparatively studied on the grounds of static DFT and Car-Parrinello molecular dynamics simulations. The BN/CC butanes CH3 CH2 BH2 NH3 , BH3 CH2 NH2 CH3 , and NH3 CH2 BH2 CH3 were considered and compared with their isoelectronic counterparts NH3 BH2 NH2 BH3 and CH3 CH2 CH2 CH3 . In addition, systematical replacement of the NH2 BH2 fragment by the isoelectronic CH2 CH2 moiety is studied in the molecules H3 N(NH2 BH2 )3-m (CH2 CH2 )m BH3 (for m=0, 1, 2, or 3) and H3 N(NH2 BH2 )2-m (CH2 CH2 )m BH3 (for m=0, 1, or 2). The DFT and Car-Parrinello simulations show that the isosteres of the BN/CC butanes CH3 CH2 BH2 NH3 , BH3 CH2 NH2 CH3 , and NH3 CH2 BH2 CH3 and of larger oligomers of the type (BN)k (CC)l where k≥l are stable compounds. The BN/CC butane H3 NCH2 CH2 BH3 spontaneously produces molecular hydrogen at room temperature. The reaction, prompted by very strong dihydrogen bonding NH⋅⋅⋅HB, undergoes through the neutral, hypervalent, pentacoordinated boron dihydrogen complex RBH2 (H2 ) [R=(CH2 CH2 )n NH2 ]. The calculations suggest that such intermediate and the other BN/CC butanes CH3 CH2 BH2 NH3 , BH3 CH2 NH2 CH3 , and NH3 CH2 BH2 CH3 as well as larger BN/CC oligomers are viable experimentally. A simple recipe for the synthesis of CH3 CH2 BH2 NH3 is proposed. The strength of the dihydrogen bonding appeared to be crucial for the overall stability of the saturated BN/CC derivatives. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Triple Photoionization of Neon Near Threshold

    NASA Astrophysics Data System (ADS)

    Bluett, J. B.; Whitfield, S. B.; Lukić, D.; Sellin, I. A.; Azuma, Y.; Wehlitz, R.

    2002-05-01

    The threshold behavior of the triple ionization cross-section of neon was investigated using monochromatized synchotron radiation and ion time-of-flight spectroscopy. The absolute cross-section is found to follow the Wannier power law(G.H. Wannier, Phys. Rev. 90), 817 (1953). in E with an exponent of 2.27 0.25 that has a range of validity of 5.5 eV. This result is consistent with the exponent of 2.162 predicted by theory and is also consistent with the findings of Samson and Angel(J.A.R. Samson and G.C. Angel, Phys. Lett. 61), 1584 (1988).. Further tests were performed over a range of 25 eV to determine the possibility of resonances and a secondary power law for energies above 5.5 eV.

  3. Antiferromagnetism and hidden order in isoelectronic doping of URu2Si2

    DOE PAGES

    Wilson, Murray N.; Williams, Travis J.; Cai, Yipeng; ...

    2016-02-01

    In this paper, we present muon spin rotation (mu SR) and susceptibility measurements on single crystals of isoelectronically doped URu2-xTxSi2 (T = Fe, Os) for doping levels up to 50%. Zero field (ZF) μ SR measurements show long-lived oscillations demonstrating that an antiferromagnetic state exists down to low doping levels for both Os and Fe dopants. The measurements further show an increase in the internal field with doping for both Fe and Os. Comparison of the local moment-hybridization crossover temperature from susceptibility measurements and our magnetic transition temperature shows that changes in hybridization, rather than solely chemical pressure, are importantmore » in driving the evolution of magnetic order with doping.« less

  4. Isoelectronic tungsten doping in monolayer MoSe2 for carrier type modulation

    DOE PAGES

    Li, Xufan; Lin, Ming -Wei; Basile, Leonardo; ...

    2016-07-06

    Doping and alloying are effective ways to engineer the band structure and modulate the optoelectronic functionality of monolayer transition metal dichalcogenides (TMDs). In this work, we explore the synthesis and electronic properties of monolayer Mo1-xWxSe2 (0 < x < 0.18) alloys with almost 100% alloying degree. The isoelectronic substitutional doping of tungsten for molybdenum in the monolayer MoSe2 is shown to suppress its intrinsically n-type conduction behavior, with p-type conduction gradually emerging to become dominant with increasing W concentration in the alloys. Atomic resolution Z-contrast electron microscopy show that W is shown to substitute directly for Mo without the introductionmore » of noticeable vacancy or interstitial defects, however with randomly-distributed W-rich regions ~2 nm in diameter. Scanning tunneling microscopy/spectroscopy measurements reveal that these W-rich regions exhibit a local band structure with the valence band maximum (VBM) closer to the Fermi level as compared with the Mo-rich regions in the monolayer Mo1-xWxSe2 crystal. These localized upshifts of the VBM in the local band structure appear responsible for the overall p-type behavior observed for the monolayer Mo1-xWxSe2 crystals. Stacked monolayers of n-type MoSe2 and p-type Mo1-xWxSe2 were demonstrated to form atomically thin, vertically stacked p n homojunctions with gate-tunable characteristics, which appear useful for future optoelectronic applications. Lastly, these results indicate that alloying with isoelectronic dopant atoms appears to be an effective and advantageous alternate strategy to doping or alloying with electron donors or acceptors in two-dimensional TMDs.« less

  5. Isoelectronic tungsten doping in monolayer MoSe2 for carrier type modulation

    SciTech Connect

    Li, Xufan; Lin, Ming -Wei; Basile, Leonardo; Hus, Saban M.; Puretzky, Alexander A.; Lee, Jaekwang; Kuo, Yen -Chien; Chang, Lo -Yueh; Wang, Kai; Idrobo, Juan C.; Li, An -Ping; Chen, Chia-Hao; Rouleau, Christopher M.; Geohegan, David B.; Xiao, Kai

    2016-07-06

    Doping and alloying are effective ways to engineer the band structure and modulate the optoelectronic functionality of monolayer transition metal dichalcogenides (TMDs). In this work, we explore the synthesis and electronic properties of monolayer Mo1-xWxSe2 (0 < x < 0.18) alloys with almost 100% alloying degree. The isoelectronic substitutional doping of tungsten for molybdenum in the monolayer MoSe2 is shown to suppress its intrinsically n-type conduction behavior, with p-type conduction gradually emerging to become dominant with increasing W concentration in the alloys. Atomic resolution Z-contrast electron microscopy show that W is shown to substitute directly for Mo without the introduction of noticeable vacancy or interstitial defects, however with randomly-distributed W-rich regions ~2 nm in diameter. Scanning tunneling microscopy/spectroscopy measurements reveal that these W-rich regions exhibit a local band structure with the valence band maximum (VBM) closer to the Fermi level as compared with the Mo-rich regions in the monolayer Mo1-xWxSe2 crystal. These localized upshifts of the VBM in the local band structure appear responsible for the overall p-type behavior observed for the monolayer Mo1-xWxSe2 crystals. Stacked monolayers of n-type MoSe2 and p-type Mo1-xWxSe2 were demonstrated to form atomically thin, vertically stacked p n homojunctions with gate-tunable characteristics, which appear useful for future optoelectronic applications. Lastly, these results indicate that alloying with isoelectronic dopant atoms appears to be an effective and advantageous alternate strategy to doping or alloying with electron donors or acceptors in two-dimensional TMDs.

  6. Isoelectronic tungsten doping in monolayer MoSe2 for carrier type modulation

    SciTech Connect

    Li, Xufan; Lin, Ming -Wei; Basile, Leonardo; Hus, Saban M.; Puretzky, Alexander A.; Lee, Jaekwang; Kuo, Yen -Chien; Chang, Lo -Yueh; Wang, Kai; Idrobo, Juan C.; Li, An -Ping; Chen, Chia-Hao; Rouleau, Christopher M.; Geohegan, David B.; Xiao, Kai

    2016-07-06

    Doping and alloying are effective ways to engineer the band structure and modulate the optoelectronic functionality of monolayer transition metal dichalcogenides (TMDs). In this work, we explore the synthesis and electronic properties of monolayer Mo1-xWxSe2 (0 < x < 0.18) alloys with almost 100% alloying degree. The isoelectronic substitutional doping of tungsten for molybdenum in the monolayer MoSe2 is shown to suppress its intrinsically n-type conduction behavior, with p-type conduction gradually emerging to become dominant with increasing W concentration in the alloys. Atomic resolution Z-contrast electron microscopy show that W is shown to substitute directly for Mo without the introduction of noticeable vacancy or interstitial defects, however with randomly-distributed W-rich regions ~2 nm in diameter. Scanning tunneling microscopy/spectroscopy measurements reveal that these W-rich regions exhibit a local band structure with the valence band maximum (VBM) closer to the Fermi level as compared with the Mo-rich regions in the monolayer Mo1-xWxSe2 crystal. These localized upshifts of the VBM in the local band structure appear responsible for the overall p-type behavior observed for the monolayer Mo1-xWxSe2 crystals. Stacked monolayers of n-type MoSe2 and p-type Mo1-xWxSe2 were demonstrated to form atomically thin, vertically stacked p n homojunctions with gate-tunable characteristics, which appear useful for future optoelectronic applications. Lastly, these results indicate that alloying with isoelectronic dopant atoms appears to be an effective and advantageous alternate strategy to doping or alloying with electron donors or acceptors in two-dimensional TMDs.

  7. NEON's Mobile Deployment Platform: Seeking Input on a Community Resource

    NASA Astrophysics Data System (ADS)

    SanClements, M.; Loescher, H. W.

    2012-12-01

    We seek input from the AGU community on the National Ecological Observatory Network's (NEON) PI and agency requestable Mobile Deployment Platform (MDP). The NEON MDPs will provide the means to observe stochastic or spatially important events, gradients, or quantities that cannot be reliably observed using fixed location sampling (e.g. fires and floods). Due to the transient temporal and spatial nature of such events, the MDPs will be designed to accommodate rapid deployment for time periods up to ~ 1 year. Broadly, the MDPs will be comprised of infrastructure and instrumentation capable of functioning individually or in conjunction with one another to support observations of ecological change, as well as education, training and outreach. We aim to glean input on selecting infrastructure and instrumentation relevant to meeting the needs of NEON and the broader scientific community. This poster will be formatted to allow for direct commentary on the MDP. Comments will be compiled and made available on the NEON website for further discussion.

  8. 8. DETAIL OF NORTHEAST ELEVATION SHOWING NEON TWA SIGN AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. DETAIL OF NORTHEAST ELEVATION SHOWING NEON TWA SIGN AND ROOF MASTS. LOOKING SOUTHWEST. - TWA Maintenance Hangar, South side of Tinicum Island Road, Philadelphia International Airport, Philadelphia, Philadelphia County, PA

  9. Core level photoelectron spectroscopy probed heterogeneous xenon/neon clusters

    NASA Astrophysics Data System (ADS)

    Pokapanich, Wandared; Björneholm, Olle; Öhrwall, Gunnar; Tchaplyguine, Maxim

    2017-06-01

    Binary rare gas clusters; xenon and neon which have a significant contrariety between sizes, produced by a co-expansion set up and have been studied using synchrotron radiation based x-ray photoelectron spectroscopy. Concentration ratios of the heterogeneous clusters; 1%, 3%, 5% and 10% were controlled. The core level spectra were used to determine structure of the mixed cluster and analyzed by considering screening mechanisms. Furthermore, electron binding energy shift calculations demonstrated cluster aggregation models which may occur in such process. The results showed that in the case of low mixing ratios of 3% and 5% of xenon in neon, the geometric structures exhibit xenon in the center and xenon/neon interfaced in the outer shells. However, neon cluster vanished when the concentration of xenon was increased to 10%.

  10. Developments of thick solid neon as an active target

    NASA Astrophysics Data System (ADS)

    Kamiguchi, Nagaaki; Moriguchi, Tetsurou; Ozawa, Akira; Isimoto, Sigeru

    2009-10-01

    One of research subjects in our group is to measure reaction cross sections (σR) of RI beams. By measuring σR, we can deduce root mean square radii of unstable nuclei. In the measurements of σR, we usually used a carbon as the reaction targets (a few cm thickness). If we use the reaction target as a detector (active target), there are some advantages in the measurements; (1)The events only colliding with the reaction target can be selected. (2)If position information is available, we may define the colliding point inside the target. (3)If energy information is available, we may measure the energy loss of the beams inside the target. As the active target in the σR measurements, we noticed the solid neon. Since the neon is a noble gas, it is predicted to emit scintillations and work as an ionization chamber for charged particles. Indeed, scintillations from liquid and solid neon have been already observed. We will present production of the thick solid neon (˜30mm thickness), and observations of scintillations and ionization signals from the solid neon. We will also discuss possibility to use the sold neon as the active target in the σR measurements.

  11. Neon distribution in South Atlantic and South Pacific waters

    NASA Astrophysics Data System (ADS)

    Well, Roland; Roether, Wolfgang

    2003-06-01

    We present and assess the distribution of neon in South Atlantic and South Pacific waters, on the basis of more than 3000 mostly new neon data which were obtained primarily under the hydrographic program of the World Ocean Circulation Experiment (predominantly southern summer to fall cruises). Data precision is better than±0.5%, and the set is internally consistent within±0.3% and partly better, and compatible with reported high-quality neon values. Using suitably averaged data (precision 0.1-0.3%), we find that the total range of neon anomalies relative to a solubility equilibrium with atmospheric neon at the observed potential temperature and salinity (using the solubilities of Weiss, J. Chem. Eng. Data 16 (1971) 235) is approximately 0-4%, and below 2000 m depth, 3-4% only. We consistently observe two types of neon depth profiles, one for the temperate-latitudes ocean, which is characterized by a near-surface maximum and a minimum in Antarctic Intermediate Water, and one for the Southern Ocean that essentially displays a steady increase with depth. The neon distribution reflects the influence of air injected by submerged air bubbles, the areal distribution of atmospheric pressure, seasonal temperature changes in the mixed layer and solar heating below it, and interaction with sea ice and glacial ice, largely in keeping with previous work. However, it appears that interaction with sea ice reduces neon anomalies distinctly less than the literature suggests. The temperate-ocean shallow maxima point to widespread subsurface heating in the course of the summer season by roughly 1 K. Among the major source water masses of the deep waters, the neon anomalies are lowest in Antarctic Intermediate Water (˜1.5%), intermediate in North Atlantic Deep Water (˜3%, confirming previous work) and similarly in Circumpolar Deep Water, and highest in Antarctic Bottom Water (˜3.8%). The anomalies in Southeast Pacific deep waters (>2500 m) are comparatively less (only˜3.3%), as

  12. On the origins of trapped helium, neon and argon isotopic variations in meteorites. I - Gas-rich meteorites, lunar soil and breccia. II - Carbonaceous meteorites.

    NASA Technical Reports Server (NTRS)

    Black, D. C.

    1972-01-01

    Data are presented from stepwise heating experiments and total extractions on five meteorites: Kapoeta, Fayetteville, Holman Island, Cee Vee, and Pultusk. These data reveal the presence of four isotopically distinct trapped neon components. A comparison of trapped neon with trapped helium and argon in bulk analyses indicates the existence of correlated helium, neon and argon isotopic structures. Component B is attributed primarily to direct implantation of rare gas ions by the present day solar wind. Component C is identified with directly implanted low energy (1-10 Mev/n) solar flare rare gases. Component D is associated with rare gas ions implanted in meteoritic material by the primitive, pre-main sequence, solar wind. A fourth component, observed only in Kapoeta and the lunar fines and breccia, is tentatively attributed to parent body 'atmospheric' ions implanted in surface material by a solar wind induced electric field.

  13. On the origins of trapped helium, neon and argon isotopic variations in meteorites. I - Gas-rich meteorites, lunar soil and breccia. II - Carbonaceous meteorites.

    NASA Technical Reports Server (NTRS)

    Black, D. C.

    1972-01-01

    Data are presented from stepwise heating experiments and total extractions on five meteorites: Kapoeta, Fayetteville, Holman Island, Cee Vee, and Pultusk. These data reveal the presence of four isotopically distinct trapped neon components. A comparison of trapped neon with trapped helium and argon in bulk analyses indicates the existence of correlated helium, neon and argon isotopic structures. Component B is attributed primarily to direct implantation of rare gas ions by the present day solar wind. Component C is identified with directly implanted low energy (1-10 Mev/n) solar flare rare gases. Component D is associated with rare gas ions implanted in meteoritic material by the primitive, pre-main sequence, solar wind. A fourth component, observed only in Kapoeta and the lunar fines and breccia, is tentatively attributed to parent body 'atmospheric' ions implanted in surface material by a solar wind induced electric field.

  14. Graphene engineering by neon ion beams

    SciTech Connect

    Iberi, Vighter; Ievlev, Anton V.; Vlassiouk, Ivan; Jesse, Stephen; Kalinin, Sergei V.; Joy, David C.; Rondinone, Adam J.; Belianinov, Alex; Ovchinnikova, Olga S.

    2016-02-18

    Achieving the ultimate limits of materials and device performance necessitates the engineering of matter with atomic, molecular, and mesoscale fidelity. While common for organic and macromolecular chemistry, these capabilities are virtually absent for 2D materials. In contrast to the undesired effect of ion implantation from focused ion beam (FIB) lithography with gallium ions, and proximity effects in standard e-beam lithography techniques, the shorter mean free path and interaction volumes of helium and neon ions offer a new route for clean, resist free nanofabrication. Furthermore, with the advent of scanning helium ion microscopy, maskless He+ and Ne+ beam lithography of graphene based nanoelectronics is coming to the forefront. Here, we will discuss the use of energetic Ne ions in engineering graphene devices and explore the mechanical, electromechanical and chemical properties of the ion-milled devices using scanning probe microscopy (SPM). By using SPM-based techniques such as band excitation (BE) force modulation microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy, we demonstrate that the mechanical, electrical and optical properties of the exact same devices can be quantitatively extracted. Additionally, the effect of defects inherent in ion beam direct-write lithography, on the overall performance of the fabricated devices is elucidated.

  15. Graphene engineering by neon ion beams

    DOE PAGES

    Iberi, Vighter; Ievlev, Anton V.; Vlassiouk, Ivan; ...

    2016-02-18

    Achieving the ultimate limits of materials and device performance necessitates the engineering of matter with atomic, molecular, and mesoscale fidelity. While common for organic and macromolecular chemistry, these capabilities are virtually absent for 2D materials. In contrast to the undesired effect of ion implantation from focused ion beam (FIB) lithography with gallium ions, and proximity effects in standard e-beam lithography techniques, the shorter mean free path and interaction volumes of helium and neon ions offer a new route for clean, resist free nanofabrication. Furthermore, with the advent of scanning helium ion microscopy, maskless He+ and Ne+ beam lithography of graphenemore » based nanoelectronics is coming to the forefront. Here, we will discuss the use of energetic Ne ions in engineering graphene devices and explore the mechanical, electromechanical and chemical properties of the ion-milled devices using scanning probe microscopy (SPM). By using SPM-based techniques such as band excitation (BE) force modulation microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy, we demonstrate that the mechanical, electrical and optical properties of the exact same devices can be quantitatively extracted. Additionally, the effect of defects inherent in ion beam direct-write lithography, on the overall performance of the fabricated devices is elucidated.« less

  16. Neon color spreading in dynamic displays: temporal factors.

    PubMed

    Cicchini, Marco; Spillmann, Lothar

    2013-10-04

    When a red star is placed in the middle of an Ehrenstein figure so as to be collinear with the surrounding black rays, a reddish veil is perceived to fill the white center. This is called neon color spreading. To better understand the processes that give rise to this phenomenon, we studied the temporal properties of the effect. Specifically, we presented a "sustained" black Ehrenstein figure (rays) for 600 ms and a "transient" red star for 48 ms, or the converse pattern, at various stimulus onset asynchronies (-100-700 ms) and asked subjects to compare the strength of the neon color in the test stimulus to that of a reference pattern in which the transient star had an onset asynchrony of 300 ms. Additional exposure durations of 24 and 96 ms were used for each transient stimulus in order to study the effect of temporal integration. Simultaneity of the on- and off-transients of the star and the Ehrenstein rays were found to optimize neon color spreading, especially when both stimuli terminated together. Longer exposure durations of the transient stimulus up to 96 ms further improved the effect. Neon color spreading was much reduced when the transient stimulus was presented soon after the beginning of the sustained stimulus, with a gradual build-up towards the end. These results emphasize the importance of stimulus onset asynchrony (SOA) and stimulus termination asynchrony (STA) for the perception of neon color spreading.

  17. Hydrodynamic models for novae with ejecta rich in oxygen, neon and magnesium

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Sparks, W. M.; Truran, J. W.

    1985-01-01

    The characteristics of a new class of novae are identified and explained. This class consists of those objects that have been observed to eject material rich in oxygen, neon, magnesium, and aluminum at high velocities. We propose that for this class of novae the outburst is occurring not on a carbon-oxygen white dwarf but on an oxygen-neon-magnesium white dwarf which has evolved from a star which had a main sequence mass of approx. 8 solar masses to approx. 12 solar masses. An outburst was simulated by evolving 1.25 solar mass white dwarfs accreting hydrogen rich material at various rates. The effective enrichment of the envelope by ONeMg material from the core is simulated by enhancing oxygen in the accreted layers. The resulting evolutionary sequences can eject the entire accreted envelope plus core material at high velocities. They can also become super-Eddington at maximum bolometric luminosity. The expected frequency of such events (approx. 1/4) is in good agreement with the observed numbers of these novae.

  18. X-ray absorption in neon modulated by a strong laser pulse

    NASA Astrophysics Data System (ADS)

    Hertlein, M. P.; Glover, T. E.; Allison, T. K.; van Tilborg, J.; Rude, B. S.; Belkacem, A.; Southworth, S. H.; Kanter, E. P.; Krässig, B.; Varma, H. R.; Santra, R.; Young, L.

    2009-11-01

    We have measured the absorption of x-rays in neon gas in the presence of a strong laser pulse. The femtosecond x-rays were tuned to energies near the neon 1s-3p resonance, and the laser intensity of 1013 W/cm2 was below the intensity required to alone ionize neon. We observed strong modification of the x-ray absorption when the neon was subjected to laser light that was temporally overlapped with the x-rays.

  19. Magneto-optical properties and recombination dynamics of isoelectronic bound excitons in ZnO

    SciTech Connect

    Chen, S. L.; Chen, W. M.; Buyanova, I. A.

    2014-02-21

    Magneto-optical and time-resolved photoluminescence (PL) spectroscopies are employed to evaluate electronic structure of a bound exciton (BX) responsible for the 3.364 eV line (labeled as I{sub 1}{sup *}) in bulk ZnO. From time-resolved PL spectroscopy, I{sub 1}{sup *} is concluded to originate from the exciton ground state. Based on performed magneto-PL studies, the g-factors of the involved electron and hole are determined as being g{sub e} = 1.98 and g{sub h}{sup ∥}(g{sub h}{sup ⊥}) = 1.2(1.62), respectively. These values are nearly identical to the reported g-factors for the I{sup *} line in ZnO (Phys. Rev. B 86, 235205 (2012)), which proves that I{sub 1}{sup *} should have a similar origin as I{sup *} and should arise from an exciton bound to an isoelectronic center with a hole-attractive potential.

  20. Oxygen-Boron Vacancy Defect in Cubic Boron Nitride: A Diamond NV- Isoelectronic Center

    NASA Astrophysics Data System (ADS)

    Abtew, Tesfaye; Gao, Weiwei; Gao, Xiang; Sun, Yiyang; Zhang, Shengbai; Zhang, Peihong

    2015-03-01

    The promises of NV? center in diamond for quantum information application have inspired unprecedented research interests in optical manipulations of defect states, and have stimulated the search for alternative isoelectronic defect systems. In this talk, we present a diamond NV- like color center in c-BN based on first-principles electronic structure calculations using the Heyd-Scuseria-Ernzerhof hybrid functional. The defect consists of an substitutional oxygen and an adjacent boron vacancy (ON -VB). We discuss the electronic and optical properties of this center in comparison with the NV- center GC-2 defect center in c-BN. We acknowledge the computational support provided by the Center for Computational Research at the University at Buffalo, SUNY. This work is supported by the US Department of Energy under Grant No. DE-SC0002623 and by the National Science Foundation under Grant No. DMR-0946404. Work at Beijing CSRC is supported by the National Natural Science Foundation of China (Grant No. 11328401).

  1. NEON INSIGHTS FROM OLD SOLAR X-RAYS: A PLASMA TEMPERATURE DEPENDENCE OF THE CORONAL NEON CONTENT

    SciTech Connect

    Drake, Jeremy J.

    2011-12-10

    An analysis using modern atomic data of fluxes culled from the literature for O VIII and Ne IX lines observed in solar active regions by the P78 and Solar Maximum Mission satellites confirms that the coronal Ne/O abundance ratio varies by a factor of two or more, and finds an increase in Ne/O with increasing active region plasma temperature. The latter is reminiscent of evidence for increasing Ne/O with stellar activity in low-activity coronae that reaches a 'neon saturation' in moderately active stars at approximately twice the historically accepted solar value of about 0.15 by number. We argue that neon saturation represents the underlying stellar photospheric compositions, and that low-activity coronae, including that of the Sun, are generally depleted in neon. The implication would be that the solar Ne/O abundance ratio should be revised upward by a factor of about two to n(Ne)/n(O) {approx} 0.3. Diverse observations of neon in the local cosmos provide some support for such a revision. Neon would still be of some relevance for reconciling helioseismology with solar models computed using recently advocated chemical mixtures with lower metal content.

  2. Neon dc glow discharge at cryogenic cooling: experiment and simulation

    NASA Astrophysics Data System (ADS)

    Shumova, V. V.; Polyakov, D. N.; Vasilyak, L. M.

    2017-10-01

    The results of the measurement and simulation of electrical characteristics of neon dc discharge are presented. These results have been obtained in the discharge cooled to the temperature of liquid nitrogen (77 K). The experiments were carried out at a neon pressure of 18–187 Pa and a discharge current of 0.01–3.5 mA. Cooling in the subnormal discharge mode at a constant value of discharge current led to a change in the discharge mode. When cooled, the electric field in the positive column and at the boundary of the transition to the normal discharge increased, and the reduced electric field decreased in all the investigated ranges of discharge current, pressure and neon concentration. The simulation of the positive column, based on the diffusion-drift (fluid) model, has shown that the input in the ionization of processes involving excited atoms increases with decreasing discharge temperature.

  3. Monte Carlo simulations of nanoscale focused neon ion beam sputtering.

    PubMed

    Timilsina, Rajendra; Rack, Philip D

    2013-12-13

    A Monte Carlo simulation is developed to model the physical sputtering of aluminum and tungsten emulating nanoscale focused helium and neon ion beam etching from the gas field ion microscope. Neon beams with different beam energies (0.5-30 keV) and a constant beam diameter (Gaussian with full-width-at-half-maximum of 1 nm) were simulated to elucidate the nanostructure evolution during the physical sputtering of nanoscale high aspect ratio features. The aspect ratio and sputter yield vary with the ion species and beam energy for a constant beam diameter and are related to the distribution of the nuclear energy loss. Neon ions have a larger sputter yield than the helium ions due to their larger mass and consequently larger nuclear energy loss relative to helium. Quantitative information such as the sputtering yields, the energy-dependent aspect ratios and resolution-limiting effects are discussed.

  4. Helium and neon isotopes in deep Pacific Ocean sediments

    NASA Technical Reports Server (NTRS)

    Nier, A. O.; Schlutter, D. J.; Brownlee, D. E.

    1990-01-01

    Helium and neon concentration measurements, along with isotope ratio determinations, have been made for particles collected in the deep Pacific with a magnetic sled, and they are believed to be of extraterrestrial origin. Analyses were made for samples consisting of composites of many extremely fine particles and for several individual particles large enough to contain sufficient gas for analysis but small enough to escape melting in their passage through the atmosphere. Step-heating was employed to extract the gas. Cosmic-ray spallation products or solar-wind helium and neon, if present, were not abundant enough to account for the isotopic compositions measured. In the case of the samples of magnetic fines, the low temperature extractions provided elemental and isotopic ratios in the general range found for the primordial gas in carbonaceous chondrites and gas-rich meteorites. The isotopic ratios found in the high temperature extractions suggest the presence of solar-flare helium and neon.

  5. Helium and neon isotopes in deep Pacific Ocean sediments

    NASA Technical Reports Server (NTRS)

    Nier, A. O.; Schlutter, D. J.; Brownlee, D. E.

    1990-01-01

    Helium and neon concentration measurements, along with isotope ratio determinations, have been made for particles collected in the deep Pacific with a magnetic sled, and they are believed to be of extraterrestrial origin. Analyses were made for samples consisting of composites of many extremely fine particles and for several individual particles large enough to contain sufficient gas for analysis but small enough to escape melting in their passage through the atmosphere. Step-heating was employed to extract the gas. Cosmic-ray spallation products or solar-wind helium and neon, if present, were not abundant enough to account for the isotopic compositions measured. In the case of the samples of magnetic fines, the low temperature extractions provided elemental and isotopic ratios in the general range found for the primordial gas in carbonaceous chondrites and gas-rich meteorites. The isotopic ratios found in the high temperature extractions suggest the presence of solar-flare helium and neon.

  6. Purification and Liquefacttion of Neon Using a Helium Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Boeck, S.

    2010-04-01

    The cryogenic plant developed by Linde Kryotechnik is used to extract neon out of a crude gas flow coming from an air separation plant. The crude gas is cooled down by a two stage helium refrigeration process using the Linde Kryotechnik dynamic gas bearing turbines. After the first cooling stage, nitrogen is liquefied and separated from the crude gas. The Cryogenic adsorbers located at a temperature level below 80 K clean the crude gas from remaining nitrogen traces before the neon-helium mixture enters the final cooling stage. In the second cooling stage neon is liquefied and separated from the helium. The final product quality will be achieved within a rectification column at low pressure level.

  7. Boiling incipience and convective boiling of neon and nitrogen

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Hendricks, R. C.

    1977-01-01

    Forced convection and subcooled boiling heat transfer data for liquid nitrogen and liquid neon were obtained in support of a design study for a 30 tesla cryomagnet cooled by forced convection of liquid neon. The cryogen data obtained over a range of system pressures, fluid flow rates, and applied heat fluxes were used to develop correlations for predicting boiling incipience and convective boiling heat transfer coefficients in uniformly heated flow channels. The accuracy of the correlating equations was then evaluated. A technique was also developed to calculate the position of boiling incipience in a uniformly heated flow channel. Comparisons made with the experimental data showed a prediction accuracy of + or - 15 percent.

  8. Cascade units for neon isotope production by rectification

    NASA Astrophysics Data System (ADS)

    Bondarenko, V. L.; Simonenko, Yu. M.; Diachenko, O. V.; Matveyev, E. V.

    2013-05-01

    The basics of neon isotope separation by the distillation method at T = 28 K are discussed. The required numbers of transfer units at the top and bottom column sections are calculated for different loads. The experimental characteristics of packed rectification columns are presented and examples of the cascade are discussed. A configuration for a cryogenic circuit based on a high-pressure throttle neon cycle with intermediate nitrogen cooling is presented. The necessity for and the technical feasibility of creating a driver pressure difference between the columns for different stages are demonstrated.

  9. Triple Photoionization of Neon and Argon Near Threshold

    NASA Astrophysics Data System (ADS)

    Bluett, Jaques B.; Lukić, Dragan; Sellin, Ivan A.; Whitfield, Scott B.; Wehlitz, Ralf

    2003-05-01

    The threshold behavior of the triple ionization cross-section of neon and argon was investigated using monochromatized synchrotron radiation and ion time-of-flight spectrometry. The Ne^3+ and Ar^3+ cross-sections are found to follow the Wannier power law(G.H. Wannier, Phys. Rev. 90), 817 (1953). consistent with a Wannier exponent of 2.162 predicted by theory. This is also consistent with the findings of Samson and Angel(J.A.R. Samson and G.C. Angel, Phys. Lett. 61), 1584 (1988). for the case of Ne. In the case of argon we find a much shorter range of validity than for neon.

  10. Fast imaging of intact and shattered cryogenic neon pellets.

    PubMed

    Wang, Zhehui; Combs, S K; Baylor, L R; Foust, C R; Lyttle, M S; Meitner, S J; Rasmussen, D A

    2014-11-01

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100-µm- and sub-µs-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of µm to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development.

  11. Comparison of the incremental and hierarchical methods for crystalline neon.

    PubMed

    Nolan, S J; Bygrave, P J; Allan, N L; Manby, F R

    2010-02-24

    We present a critical comparison of the incremental and hierarchical methods for the evaluation of the static cohesive energy of crystalline neon. Both of these schemes make it possible to apply the methods of molecular electronic structure theory to crystalline solids, offering a systematically improvable alternative to density functional theory. Results from both methods are compared with previous theoretical and experimental studies of solid neon and potential sources of error are discussed. We explore the similarities of the two methods and demonstrate how they may be used in tandem to study crystalline solids.

  12. Peaked density profiles due to neon injection on FTU

    NASA Astrophysics Data System (ADS)

    Mazzotta, C.; Bañón Navarro, A.; Gabellieri, L.; Marinucci, M.; Pucella, G.; Told, D.; Tudisco, O.; Apruzzese, G.; Artaserse, G.; Sozzi, C.; the FTU Team

    2015-07-01

    Neon injection in FTU can cause a spontaneous increase of the line-average density by a factor 2. The recent experiments were devoted to characterize the plasma response to the neon injection at different densities and plasma currents. A qualitative estimate from UV spectroscopy measurements indicates that the density behaviour cannot be attributed simply to the stripped electrons from the puffed impurity, but a modification of particle transport should be invoked in order to explain the spontaneous rise and the higher peaking. JETTO transport and GENE gyrokinetic codes analyses, as well as a calculation of the electron diffusion coefficients D and pinch velocity U, contribute to feature the peaking effect.

  13. Fast Imaging of Intact and Shattered Cryogenic Neon Pellets

    SciTech Connect

    Wang, Zhehui; Combs, Stephen Kirk; Baylor, Larry R; Foust, Charles R; Lyttle, Mark S; Meitner, Steven J; Rasmussen, David A

    2014-01-01

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100- m- and sub- s-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of m to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development.

  14. Fast imaging of intact and shattered cryogenic neon pellets

    SciTech Connect

    Wang, Zhehui; Combs, S. K.; Baylor, L. R.; Foust, C. R.; Lyttle, M. S.; Meitner, S. J.; Rasmussen, D. A.

    2014-11-15

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100-µm- and sub-µs-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of µm to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development.

  15. Comparison of Theoretical and Experimental Level Values of the n = 2 Complex in Ions Isoelectronic with Li, Be, O and F

    NASA Astrophysics Data System (ADS)

    Edlén, Bengt

    1983-07-01

    The differences between observed and theoretical values of level intervals within the n = 2 complex in ions isoelectronic with Li, Be, O and F have been studied as functions of Z. The theoretical values are based on the tables of Cheng, Kim and Desclaux. For spin-orbit intervals, σ (theor) is taken as their multiconfiguration Dirac-Fock value with Breit correction (MCDF + B), for other intervals within the same configuration the Z-independent correlation energy from Cheng, Froese Fischer and Kim is added, and for interconfiguration intervals a Lamb-shift correction is also included, obtained by transforming the values of Cheng et al. into a smooth function of Z. The difference σ (obs) - σ (theor) is then expressed by the formula A + B(Z - C)-1 + a(Z - s)x, where the first two terms account for the residual correlation energy and the last term comprises all additional relativistic and radiative corrections. In a few cases we had to use two such terms with opposite sign and exponents differing by 2 to 3 units. The constants A, B, C, a and x are adjusted to fit the observations within their error limits. As compared to a fitted polynomial, the present formula is much better suited for extrapolation and provides a sharper test of the experimental data, especially at the high-Z end of a sequence. It has revealed a number of incorrect line identifications in the Be sequence. The results of the analyses are summarized in tables of recommended level values and wavelengths, extending to Z = 36 and in some cases to Z = 42. The wavelengths obtained for the resonance lines in the Be, O and F sequences may become useful as wavelength standards.

  16. A Wsbnd Ne interatomic potential for simulation of neon implantation in tungsten

    NASA Astrophysics Data System (ADS)

    Backman, Marie; Juslin, Niklas; Huang, Guiyang; Wirth, Brian D.

    2016-08-01

    An interatomic pair potential for Wsbnd Ne is developed for atomistic molecular dynamics simulations of neon implantation in tungsten. The new potential predicts point defect energies and binding energies of small clusters that are in good agreement with electronic structure calculations. Molecular dynamics simulations of small neon clusters in tungsten show that trap mutation, in which an interstitial neon cluster displaces a tungsten atom from its lattice site, occurs for clusters of three or more neon atoms. However, near a free surface, trap mutation can occur at smaller sizes, including even a single neon interstitial in close proximity to a (100) or (110) surface.

  17. Self-assembled heterogeneous argon/neon core-shell clusters studied by photoelectron spectroscopy.

    PubMed

    Lundwall, M; Pokapanich, W; Bergersen, H; Lindblad, A; Rander, T; Ohrwall, G; Tchaplyguine, M; Barth, S; Hergenhahn, U; Svensson, S; Björneholm, O

    2007-06-07

    Clusters formed by a coexpansion process of argon and neon have been studied using synchrotron radiation. Electrons from interatomic Coulombic decay as well as ultraviolet and x-ray photoelectron spectroscopy were used to determine the heterogeneous nature of the clusters and the cluster structure. Binary clusters of argon and neon produced by coexpansion are shown to exhibit a core-shell structure placing argon in the core and neon in the outer shells. Furthermore, the authors show that 2 ML of neon on the argon core is sufficient for neon valence band formation resembling the neon solid. For 1 ML of neon the authors observe a bandwidth narrowing to about half of the bulk value.

  18. NEON Data Products: Enabling Continental-Scale Ecological Science

    NASA Astrophysics Data System (ADS)

    Berukoff, S. J.

    2011-12-01

    The National Ecological Observatory Network (NEON) is a NSF-funded major research and facilities initiative under development, designed to address how climate change, land use change, and invasive species affect ecological science on a continental scale. The standardization of measurement methodologies, engineering practice, and data organization across NEON's sixty sites fosters the creation of ecological data products. These data products are community-approved and Observatory-vetted, and cover the breadth of NEON collection activities, including measurements of physical variables such as air, water, and soil temperature and chemistry, observations and analyses of species and habitats, and airborne spectral and LiDAR remote sensing. Together, these low-level (fundamental measurement and observation data)and high-level (integrative, continental-scale assessments) will be useful for scientists, students, educators, policymakers, and the general public. Here, we discuss the development status of NEON's data product suites, describing how they are constructed and vetted, and provide an example of how one current effort will provide several foundational data products. Further, we discuss and solicit feedback for how stakeholder communities can contribute to their veracity and validation.

  19. Molecular Iodine Fluorescence Using a Green Helium-Neon Laser

    ERIC Educational Resources Information Center

    Williamson, J. Charles

    2011-01-01

    Excitation of molecular iodine vapor with a green (543.4 nm) helium-neon laser produces a fluorescence spectrum that is well suited for the upper-level undergraduate physical chemistry laboratory. Application of standard evaluation techniques to the spectrum yields ground electronic-state molecular parameters in good agreement with literature…

  20. A Closed Neon Liquefier System for Testing Superconducting Devices

    NASA Astrophysics Data System (ADS)

    Bianchetti, M.; Al-Mosawi, M. K.; Yang, Y.; Beduz, C.; Giunchi, G.

    2006-04-01

    A Neon liquefier system has been developed by Southampton University (UK) and EDISON (Italy) with the aim to provide a facility for testing HTS superconducting devices using Magnesium Diboride materials, in the range 25-30K. The system consists of a liquid Neon cryostat coupled to a two stages cryocooler and a recovery system. The first stage of the cryocooler is connected to the thermal shield of the cryostat and a copper station positioned at mid point along the access neck to the liquid Neon bath to reduce heat leak and to provide pre-cooling of samples. The second stage, capable of 20W cooling power at 22K, is used to provide the cooling power for liquefaction and to refrigerate the liquid Neon bath and the superconducting device/sample during the steady state operation. The recovery system has been designed to automatically compress excess boil-off generated by a quench or a transient heating into a storage gas container. Transport measurement up to 900A can be carried out in the Ne cryostat using purposely build hybrid current leads. These leads have a copper upper section cooled by liquid Nitrogen and a superconducting lower section of Ag/AuBi2223 tapes. In this paper we report on the performance of the system and the initial measurement of superconducting samples.

  1. Neon and CO2 adsorption on open carbon nanohorns.

    PubMed

    Krungleviciute, Vaiva; Ziegler, Carl A; Banjara, Shree R; Yudasaka, Masako; Iijima, S; Migone, Aldo D

    2013-07-30

    We present the results of a thermodynamics and kinetics study of the adsorption of neon and carbon dioxide on aggregates of chemically opened carbon nanohorns. Both the equilibrium adsorption characteristics, as well as the dependence of the kinetic behavior on sorbent loading, are different for these two adsorbates. For neon the adsorption isotherms display two steps before reaching the saturated vapor pressure, corresponding to adsorption on strong and on weak binding sites; the isosteric heat of adsorption is a decreasing function of sorbent loading (this quantity varies by about a factor of 2 on the range of loadings studied), and the speed of the adsorption kinetics increases with increasing loading. By contrast, for carbon dioxide there are no substeps in the adsorption isotherms; the isosteric heat is a nonmonotonic function of loading, the value of the isosteric heat never differs from the bulk heat of sublimation by more than 15%, and the kinetic behavior is opposite to that of neon, with equilibration times increasing for higher sorbent loadings. We explain the difference in the equilibrium properties observed for neon and carbon dioxide in terms of differences in the relative strengths of adsorbate-adsorbate to adsorbate-sorbent interaction for these species.

  2. Elemental abundances of flaring solar plasma - Enhanced neon and sulfur

    NASA Technical Reports Server (NTRS)

    Schmelz, J. T.

    1993-01-01

    Elemental abundances of two flares observed with the SMM Flat Crystal Spectrometer are compared and contrasted. The first had a gradual rise and a slow decay, while the second was much more impulsive. Simultaneous spectra of seven bright soft X-ray resonance lines provide information over a broad temperature range and are available throughout both flares, making these events unique in the SMM data base. For the first flare, the plasma seemed to be characterized by coronal abundances but, for the second, the plasma composition could not be coronal, photospheric, or a linear combination of both. A good differential emission measure fit required enhanced neon such that Ne/O = 0.32 +/- 0.02, a value which is inconsistent with the current models of coronal abundances based on the elemental first-ionization potential. Similar values of enhanced neon are found for flaring plasma observed by the SMM gamma-ray spectrometer, in (He-3)-rich solar energetic particle events, and in the decay phase of several long duration soft X-ray events. Sulfur is also enhanced in the impulsive flare, but not as dramatically as neon. These events are compared with two models which attempt to explain the enhanced values of neon and sulfur.

  3. Molecular Iodine Fluorescence Using a Green Helium-Neon Laser

    ERIC Educational Resources Information Center

    Williamson, J. Charles

    2011-01-01

    Excitation of molecular iodine vapor with a green (543.4 nm) helium-neon laser produces a fluorescence spectrum that is well suited for the upper-level undergraduate physical chemistry laboratory. Application of standard evaluation techniques to the spectrum yields ground electronic-state molecular parameters in good agreement with literature…

  4. Cosmogenic neon from precompaction irradiation of Kapoeta and Murchison

    NASA Technical Reports Server (NTRS)

    Caffee, M. W.; Hohenberg, C. M.; Swindle, T. D.; Goswami, J. N.

    1983-01-01

    Neon from hand-picked Murchison and Kapoeta grains, selected on the basis of the presence or absence of solar flare particle tracks, was analyzed in order to delineate the precompaction history of this material. The irradiated grains showed large enrichments of cosmogenic neon relative to the unirradiated grains. Galactic cosmic ray (GCR) exposure ages for the unirradiated grains yield the nominal values reported for the recent exposure history of these meteorites. Apparent minimum precompaction galactic exposure ages of 28 m.y. and 56 m.y. would have been obtained for Murchison and Kapoeta, respectively, if the cosmogenic effects in the irradiated grains were due to GCR irradiation. Since this seems unreasonably long, the cosmogenic neon in the irradiated grains may be due to spallation by solar cosmic rays. This, however, would require a more active early sun. The isotopic composition of the cosmogenic neon in these grains suggests a harder energy spectrum than is characteristic of present solar flares. Lack of apparent solar wind effects may require some kind of shielding, such as nebular gas.

  5. Circuit minimizes current drain caused by neon indicator lamps

    NASA Technical Reports Server (NTRS)

    Drylie, C. D.; Shaw, W. J.

    1970-01-01

    Circuit lights neon lamp by back leakage current of the driving transistor, rather than by the transistors saturation or ''on-state'' current, thereby eliminating lowering of the voltage necessary for indication. Circuit has operating speed greater than indication circuit using a saturation principle and aids in power rationing.

  6. Elemental abundances of flaring solar plasma - Enhanced neon and sulfur

    NASA Technical Reports Server (NTRS)

    Schmelz, J. T.

    1993-01-01

    Elemental abundances of two flares observed with the SMM Flat Crystal Spectrometer are compared and contrasted. The first had a gradual rise and a slow decay, while the second was much more impulsive. Simultaneous spectra of seven bright soft X-ray resonance lines provide information over a broad temperature range and are available throughout both flares, making these events unique in the SMM data base. For the first flare, the plasma seemed to be characterized by coronal abundances but, for the second, the plasma composition could not be coronal, photospheric, or a linear combination of both. A good differential emission measure fit required enhanced neon such that Ne/O = 0.32 +/- 0.02, a value which is inconsistent with the current models of coronal abundances based on the elemental first-ionization potential. Similar values of enhanced neon are found for flaring plasma observed by the SMM gamma-ray spectrometer, in (He-3)-rich solar energetic particle events, and in the decay phase of several long duration soft X-ray events. Sulfur is also enhanced in the impulsive flare, but not as dramatically as neon. These events are compared with two models which attempt to explain the enhanced values of neon and sulfur.

  7. The NEON Aquatic Network: Expanding the Availability of Biogeochemical Data

    NASA Astrophysics Data System (ADS)

    Vance, J. M.; Bohall, C.; Fitzgerald, M.; Utz, R.; Parker, S. M.; Roehm, C. L.; Goodman, K. J.; McLaughlin, B.

    2013-12-01

    Aquatic ecosystems are facing unprecedented pressure from climate change and land-use practices. Invasive species, whether plant, animal, insect or microbe present additional threat to aquatic ecosystem services. There are significant scientific challenges to understanding how these forces will interact to affect aquatic ecosystems, as the flow of energy and materials in the environment is driven by multivariate and non-linear biogeochemical cycles. The National Ecological Observatory Network (NEON) will collect and provide observational data across multiple scales. Sites were selected to maximize representation of major North American ecosystems using a multivariate geographic clustering method that partitioned the continental US, AK, HI, and Puerto Rico into 20 eco-climatic domains. The NEON data collection systems and methods are designed to yield standardized, near real-time data subjected to rigorous quality controls prior to public dissemination through an online data portal. NEON will collect data for 30 years to facilitate spatial-temporal analysis of environmental responses and drivers of ecosystem change, ranging from local through continental scales. Here we present the NEON Aquatic Network, a multi-parameter network consisting of a combination of in situ sensor and observational data. This network will provide data to examine biogeochemical, biological, hydrologic and geomorphic metrics at 36 sites, which are a combination of small 1st/2nd order wadeable streams, large rivers and lakes. A typical NEON Aquatic site will host up to two in-stream sensor sets designed to collect near-continuous water quality data (e.g. pH/ORP, temperature, conductivity, dissolved oxygen, CDOM) along with up to 8 shallow groundwater monitoring wells (level, temp., cond.), and a local meteorological station (e.g. 2D wind speed, PAR, barometric pressure, temperature, net radiation). These coupled sensor suites will be complemented by observational data (e.g. water

  8. An asymptotic expression for the dipole oscillator strength for transitions of the He sequence

    NASA Technical Reports Server (NTRS)

    Khandelwal, G. S.; Khan, F.; Wilson, J. W.

    1989-01-01

    The radial integral for 1s2 1S-1s np 1P transitions of the He isoelectronic sequence is asymptotically expanded to order n exp -7 to facilitate calculations of the dipole oscillator strength for large n. The threshold differential oscillator strength values are obtained for ions up to Z = 30 within the screened hydrogenic model.

  9. Neon isotopes show that Earth was accreted from irradiated material

    NASA Astrophysics Data System (ADS)

    Moreira, M. A.

    2015-12-01

    Since the 1980s, the notion that the Earth's mantle has a "solar" isotopic signature for neon has been favoured. Indeed, the 20Ne/22Ne ratio is above 12.5 in the mantle sources of OIB and MORB, close to the solar composition (13.4 for the Sun or 13.8 for the solar wind) and different from both atmospheric and chondritic compositions (Phase Q, Neon A). The most well accepted process invoked to explain this observed solar composition in the mantle is dissolution into a magma ocean of solar gases captured by gravity around the proto-Earth. However, Earth was accreted after gas from the proto-planetary disk had evaporated, suggesting that Earth itself could not have captured such a solar primordial atmosphere. Only planetary embryos were formed when the gas was still present in the disk. However, these planetary embryos with the mass of Mars are not massive enough to capture a solar dense atmosphere able to incorporate enough neon into the mantle. New estimates of the neon isotopic compositions of both the Earth's mantle and of the implanted solar wind into grains suggest that the origin of the neon on Earth is related to solar wind irradiation on μm grains before planetary accretion started and not dissolution. Although incorporation of solar ions by this process is only significant for very volatiles (depleted) elements, the irradiation by x-rays has important consequences for the bulk chemistry of irradiated grains as it has been demonstrated that it produces depletion in Mg and Si, relatively to O (e.g Bradley et al., 1994), a pattern also observed for the Bulk silicate Earth. References Bradley, J. (1994). "Chemically Anomalous, Preaccretionally irradiated Grains in Interplanetary fust from Comets." Science 265: 925-929.

  10. Pressure effects in the isoelectronic REFe0.85Ir0.15AsO system.

    PubMed

    Maroni, Beatrice; Di Castro, Daniele; Hanfland, Michael; Boby, Joseph; Vercesi, Cristiano; Mozzati, M Cristina; Weyeneth, Stephen; Keller, Hugo; Khasanov, Rustem; Drathen, Christina; Dore, Paolo; Postorino, Paolo; Malavasi, Lorenzo

    2011-03-16

    The effect of chemical and hydrostatic pressure has been studied systematically in a selected system belonging to the 1111 family of iron pnictide high-temperature superconductors. The results show a surprising similarity between the trend of critical temperature vs hydrostatic pressure for isoelectronic samples with different rare earths (RE) on the RE site and samples of the SmFeAsO(1-x)F(x) series with different doping levels. These results open new questions about the underlying mechanism for superconductivity in iron pnictides.

  11. Neon diffusion kinetics in olivine, pyroxene and feldspar: Retentivity of cosmogenic and nucleogenic neon

    NASA Astrophysics Data System (ADS)

    Gourbet, Loraine; Shuster, David L.; Balco, Greg; Cassata, William S.; Renne, Paul R.; Rood, Dylan

    2012-06-01

    We performed stepwise degassing experiments by heating single crystals of neutron- or proton-irradiated olivine, pyroxene and feldspar to study diffusion kinetics of neon. This is important in evaluating the utility of these minerals for cosmogenic 21Ne measurements and, potentially, for Ne thermochronometry. Degassing patterns are only partially explained by simple Arrhenius relationships; most samples do not exhibit a precisely-determined activation energy in an individual diffusion domain. Regardless, we find clear differences in diffusion kinetics among these minerals. Based on sub-selected data, our estimates for neon diffusion kinetics (activation energy Ea and pre-exponential factor Do, assuming the analyzed fragments approximate the diffusion domain) in each mineral are as follows: for the feldspars, Ea ranges from ∼65 to 115 kJ/mol and Do from 3.9 × 10-3 to 7.1 × 102 cm2s-1; for the pyroxenes, Ea ranges from ∼292 to 480 kJ/mol and Do from 1.6 × 102 to 2.9 × 1011 cm2s-1; for the olivines, Ea ranges from ∼360 to 370 kJ/mol and Do from 1.5 × 106 to 5.0 × 106 cm2s-1. Differences in these parameters are broadly consistent with the expected effect of structural differences between feldspar, and olivine and pyroxene. These results indicate that cosmogenic 21Ne will be quantitatively retained within olivine and pyroxene at Earth surface temperatures over geological timescales. The diffusion kinetics for feldspars, on the other hand, predicts that 21Ne retention at Earth surface temperatures will vary significantly with domain size, crystal microtexture, surface temperature, and exposure duration. Quantitative retention is expected only in favorable conditions. This conclusion is reinforced by additional measurements of cosmogenic 21Ne in coexisting quartz and feldspar from naturally irradiated surface samples; sanidine from a variety of rhyolitic ignimbrites exhibits quantitative retention, whereas alkali-feldspar from several granites does not.

  12. First-principles study of SO2 sensors based on phosphorene and its isoelectronic counterparts: GeS, GeSe, SnS, SnSe

    NASA Astrophysics Data System (ADS)

    Guo, Shiying; Yuan, Lu; Liu, Xuhai; Zhou, Wenhan; Song, Xiufeng; Zhang, Shengli

    2017-10-01

    Phosphorene and its isoelectronic counterparts, such as GeS, GeSe, SnS and SnSe monolayers, show great potential in electrical and sensing applications. Here, we study the SO2 sensing properties of phosphorene and its isoelectronic counterparts by first-principles calculations. Results predict that the SO2 molecule as electron acceptor holds high adsorption strength with the five monolayer substrates, especially for SnS and SnSe monolayers. Moreover, the electronic properties of the five substrates can be modified by the SO2 molecule, together with distinct charge transfer, rendering them promising for application as a high-performance gas sensor.

  13. Fractionation of terrestrial neon by hydrodynamic hydrogen escape from ancient steam atmospheres

    NASA Technical Reports Server (NTRS)

    Zahnle, K.

    1991-01-01

    Atmospheric neon is isotopically heavier than mantle neon. By contrast, nonradiogenic mantle Ar, Kr, and Xe are not known to differ from the atmosphere. These observations are most easily explained by selective neon loss to space; however, neon is much too massive to escape from the modern atmosphere. Steam atmospheres are a likely, if intermittent, feature of the accreting Earth. They occur because, on average, the energy liberated during accretion places Earth above the runaway greenhouse threshold, so that liquid water is not stable at the surface. It is found that steam atmospheres should have lasted some ten to fifty million years. Hydrogen escape would have been vigorous, but abundant heavy constituents would have been retained. There is no lack of plausible candidates; CO2, N2, or CO could all suffice. Neon can escape because it is less massive than any of the likely pollutants. Neon fractionation would have been a natural byproduct. Assuming that the initial Ne-20/Ne-22 ratio was solar, it was found that it would have taken some ten million years to effect the observed neon fractionation in a 30 bar steam atmosphere fouled with 10 bars of CO. Thicker atmospheres would have taken longer; less CO, shorter. This mechanism for fractionating neon has about the right level of efficiency. Because the lighter isotope escapes much more readily, total neon loss is pretty minimal; less than half of the initial neon endowment escapes.

  14. The energy dependence of the neon-22 excess in the cosmic radiation

    NASA Technical Reports Server (NTRS)

    Herrstroem, N. Y.; Lund, N.

    1985-01-01

    It has been recognized now for some time that the heavy neon isotope, neon-22, is overabundant by a factor of 3 to 4 with respect to neon-22 in the cosmic ray source compared to the ratio of these isotopes in the Solar System. In view of the otherwise remarkable similarity of the chemical composition of the cosmic ray source and the composition of the Solar Energetic Particles, the anomaly regarding the neon isotopes is so much more striking. The observed excess of neon-22 is too large to be explained as a result of the chemical evolution of the Galaxy since the formation of the Solar System. Further information on the origin of the neon-22 excess may come from a comparison of the energy spectra of the two neon isotopes. If the cosmic radiation in the solar neighborhood is a mixture of material from several sources, one of which has an excess of neon-22, then the source energy spectra of neon-20 and neon-22 may differ significantly.

  15. The heat of formation of chlorine-isocyanate and the relative stability of isoelectronic molecules: an experimental and theoretical study.

    PubMed

    Ji, Yuanyuan; Bobadova-Parvanova, Petia; Larson, Chris; Samartzis, Peter C; Morokuma, Keiji; Lin, Jim Jr-Min; Ching, Tao-Tsung; Chaudhuri, Chanchal; Lee, Shih-Huang; Wodtke, Alec M

    2006-06-28

    Accurate thermochemical data of small molecules are invaluable to the progress of every aspect of chemistry, especially in the atmosphere, combustion and industry. In this work, photofragmentation translational spectroscopy and 1st principles electronic structure theory reveal the literature value of the heat of formation of chlorine-isocyanate to be in error by more than 40 kcalmol. We report a revised experimental value for D0(Cl-NCO) = 51+/-3 kcal/mol which leads to a Delta Hf (ClNCO) = 8.5+/-3 kcal/mol. High level ab initio (CCSD(T)) electronic structure calculations extrapolated to the complete basis set limit give D0(Cl-NCO) = 6.3 kcal/mol, in good agreement with experiment. In light of the present results, the destabilization of azides relative to isoelectronic isocyanates has been evaluated empirically for three pairs of related molecules. It is found to be 90-110 kcal/mol, and has been attributed mainly to the weakening of the N-NN bond relative to the N-CO bond. Electronic structure calculations employing decomposition analysis suggest that, compared to homopolar N2, the (+delta)CO(-delta) pi polarity provides better orbital interaction (charge transfer) and electrostatic attraction and results in a closer encounter and larger stabilization between the fragments and that this is the origin of isoelectronic destabilization of azides relative to the isocyanates.

  16. Perception of neon color spreading in 3-6-month-old infants.

    PubMed

    Yang, Jiale; Kanazawa, So; Yamaguchi, Masami K

    2009-12-01

    Although lots of studies about neon color spreading have been reported, few of these studies have focused on the perceptual development of it in human infants. Therefore, this study explores the perceptual development of neon color spreading in infants. In experiment 1, we examined 3-6-month-olds' perception of neon color spreading in static conditions. In experiment 2, we examined 3-6-month-olds' perception of neon color spreading in moving conditions. Our results suggest that while only 5-6-month-old infants show a preference for neon color spreading in the static condition, 3-4-month-old infants also prefer neon color spreading if motion information is available.

  17. Influence of dust void on neon DC discharge

    NASA Astrophysics Data System (ADS)

    Shumova, V. V.; Polyakov, D. N.; Vasilyak, L. M.

    2017-03-01

    The diffusion/drift model of the positive column of glow discharge in neon with fine dust particles was used to study the role of a dust cloud with a void in the interaction between plasma and dust particles in the range of neon pressure and discharge current where dust particles may form structures with cavities. The results represent the nonlocal effect of void size on plasma composition, configuration of electric field and on distributions of plasma components in discharge with voids in dust structures. Simulations show that the electric field strength and the metastable atom concentration inside the void are higher than in the discharge without dust particles, while electron concentration may be either higher or lower.

  18. A Cyberinfrastructure for the National Ecological Observatory Network (NEON).

    NASA Astrophysics Data System (ADS)

    Schimel, D.; Berukoff, S. J.

    2011-12-01

    The National Ecological Observatory Network (NEON) is an NSF-funded project designed to provide physical and information infrastructure to support the development of continental-scale, quantitative ecological sciences. The network consists of sixty sites located in the continental US, Alaska, Hawaii, and Puerto Rico, each site hosting terrestrial and aquatic sensors and observational apparati that acquire data across multiple ecoclimatic domains. As well, an airborne remote sensing platform provides spectral and LiDAR data, and acquisition of data sets from external agencies allows for land-use studies. Together, this data is ingested, vetted, processed, and curated by a standards-based, provenance-driven, metadata-rich cyberinfrastructure, which will provide not only access to but discovery and manipulation of NEON data, and the construction of integrative data products and inputs for ecological forecasting that address fundamental processual questions in climate change, land use change, and invasive species.

  19. Discovery of solar wind neon in the Allende meteorite

    NASA Technical Reports Server (NTRS)

    Heymann, D.; Palma, R. L.

    1986-01-01

    Insert gases have been measured in seven sieve fractions of a disaggregated sample of the Allende meteorite. The disaggregation was done by ultrasonic treatment in water and by freeze-thawing. This sample consititutes the first gas-rich portion known to occur in the Allende meteorite. The composition of the trapped neon is solar, i.e., Neon-B, and the gas-rich samples contain more trapped Ne-20 than Ar-36. The set of sieve fractions show an anticorrelation of Ne-20 content and grain size. Gas-richness seems to be quite common among the CV3 meteorites with Allende added to the earlier known cases of Mokoia, Vigarano, and Efremovka.

  20. Neon gas target for the production of radioactive fluorine beams

    SciTech Connect

    Decrock, P.; Nolen, J.A.

    1998-01-01

    A neon gas target has been developed to produce radioactive fluorine. Small CF{sub 4} impurities were added to the neon gas and the recovery efficiency of {sup 18}F-labeled CF{sub 4} has been measured as a function of the impurity level. Extraction efficiencies up to 90{percent} have been obtained, which makes this technique to produce and extract radioactive fluorine from a production target a powerful method to generate intense radioactive {sup 17}F and {sup 18}F beams, using the {sup 20}Ne(p,{alpha}){sup 17}F and {sup 20}Ne(d,{alpha}){sup 18}F reactions, respectively. {copyright} {ital 1998 American Institute of Physics.}

  1. Atomic kinetics of a neon photoionized plasma experiment at Z

    NASA Astrophysics Data System (ADS)

    Mayes, Daniel C.; Mancini, Roberto; E Bailey, James; Loisel, Guillaume; Rochau, Gregory

    2017-06-01

    We discuss an experimental effort to study the atomic kinetics in neon photoionized plasmas via K-shell line absorption spectroscopy. The experiment employs the intense x-ray flux emitted at the collapse of a Z-pinch to heat and backlight a photoionized plasma contained within a cm-scale gas cell placed at various distances from the Z-pinch and filled with neon gas pressures in the range from 3.5 to 30 torr. The experimental platform affords an order of magnitude range in the ionization parameter characterizing the photoionized plasma from about 3 to 80 erg*cm/s. Thus, the experiment allows for the study of trends in ionization distribution as a function of the ionization parameter. An x-ray crystal spectrometer capable of collecting both time-integrated and time-gated spectra is used to collect absorption spectra. A suite of IDL programs has been developed to process the experimental data to produce transmission spectra. The spectra show line absorption by several ionization stages of neon, including Be-, Li-, He-, and H-like ions. Analysis of these spectra yields ion areal-densities and charge state distributions, which can be compared with results from atomic kinetics codes. In addition, the electron temperature is extracted from level population ratios of nearby energy levels in Li- and Be-like ions, which can be used to test heating models of photoionized plasmas.

  2. Illusory depth from moving subjective figures and neon colour spreading.

    PubMed

    Bressan, P; Vallortigara, G

    1991-01-01

    If a pattern of concentric circles, interrupted so as to produce the perception of a subjective bar extending from the centre to the periphery of the pattern, was slowly rotated in a plane perpendicular to the line of sight, observers reported seeing the bar slanted in depth and moving over complete and stationary concentric circles. When the interrupted concentric circles were completed by red segments--thereby giving rise to a neon colour-spreading effect--observers reported seeing a reddish bar, which sometimes appeared to be slanted in depth, moving behind the plane of the concentric circles. A combination of the two patterns was found to originate a compelling percept of a unitary bar slanted in depth: part of the bar (the subjective half) appeared to be located in front of its inducing elements, whereas the other part (the neon-like half) appeared to continue behind them. When translatory instead of rotary motion was used, the bars did not look slanted in depth: however, the neon bar appeared either behind or in front of the inducing lines, depending on the luminance contrast between the segments and the inducing lines themselves.

  3. Helium-neon laser improves skin repair in rabbits.

    PubMed

    Peccin, Maria Stella; Renno, Ana Claudia Muniz; de Oliveira, Flavia; Giusti, Paulo Ricardo; Ribeiro, Daniel Araki

    2012-12-01

    The purpose of this study was to evaluate the influence of helium-neon laser on skin injury in rabbits. For this purpose, 15 New Zealand rabbits underwent bilateral skin damage in leg. Helium-neon laser light, at a fluence of 6 J∕cm2 and wavelength of 632.8 nm, was applied on the left legs (laser group). The right leg lesions (control group) served as negative control. All sections were histopathologically analyzed using HE sections. The results showed little infiltration of inflammatory cells, with proliferation of fibroblasts forming a few fibrous connective tissue after 1 week post-injury. The lesion on the 3rd week was characterized by granulation tissue, which formed from proliferated fibrous connective tissue, congested blood vessels and mild mononuclear cell infiltration. On the 5th week, it was observed that debris material surrounded by a thick layer of connective tissue and dense collage, fibroblasts cells present in the dermis covered by a thick epidermal layer represented by keratinized epithelium. Taken together, our results suggest that helium-neon laser is able to improve skin repair in rabbits at early phases of recovery.

  4. Nova LMC 1990 no. 1: The first extragalactic neon nova

    NASA Technical Reports Server (NTRS)

    Sonneborn, George; Shore, Steven N.; Starrfield, Sumner G.

    1990-01-01

    International Ultraviolet Explorer (IUE) observations of nova LMC (Large Magellanic Cloud) 1990 No. 1, the first neon (or ONeMg) nova observed outside the Galaxy are presented. The observations were obtained from 17 Jan. to Mar. 1990, with especially dense coverage during the first 25 days of the outburst. (The neon nova categorization is based on the detection of forbidden Ne 3-4 lines in optical spectra; the ultraviolet neon lines were not detected.) During the first 30 days of the outburst, the radiative losses were dominated by the N 5 delta 1240 and C 4 delta 1550 lines. The maximum ejection velocity was approximately 8000 km/s, based on the blue absorption edge of the C 4 P-Cygni profile. Early in the outburst of Nova LMC 1990 No. 1 the UV luminosity alone was approximately 3 times 10 to the 38th power erg/sec, implying that the bolometric luminosity was well in excess of the Eddington luminosity for a one solar mass object.

  5. Nova LMC 1990 no. 1: The first extragalactic neon nova

    NASA Technical Reports Server (NTRS)

    Sonneborn, George; Shore, Steven N.; Starrfield, Sumner G.

    1990-01-01

    International Ultraviolet Explorer (IUE) observations of nova LMC (Large Magellanic Cloud) 1990 No. 1, the first neon (or ONeMg) nova observed outside the Galaxy are presented. The observations were obtained from 17 Jan. to Mar. 1990, with especially dense coverage during the first 25 days of the outburst. (The neon nova categorization is based on the detection of forbidden Ne 3-4 lines in optical spectra; the ultraviolet neon lines were not detected.) During the first 30 days of the outburst, the radiative losses were dominated by the N 5 delta 1240 and C 4 delta 1550 lines. The maximum ejection velocity was approximately 8000 km/s, based on the blue absorption edge of the C 4 P-Cygni profile. Early in the outburst of Nova LMC 1990 No. 1 the UV luminosity alone was approximately 3 times 10 to the 38th power erg/sec, implying that the bolometric luminosity was well in excess of the Eddington luminosity for a one solar mass object.

  6. On the mechanism of populating 3p levels of neon under pumping by a hard ioniser

    NASA Astrophysics Data System (ADS)

    Khasenov, M. U.

    2011-03-01

    The effect of quenching additives on the luminescence properties of helium — neon mixtures under pumping by α particles emitted from 210Po atoms is considered. It is concluded that, under excitation by a heavy charged particle, the population of the 3p'[1/2]0 level of neon is not related to the dissociative recombination of molecular ions. It is suggested that the most likely channels for populating the 3p level are the excitation transfer from metastable helium atoms to neon atoms and direct excitation of neon by nuclear particles and secondary electrons.

  7. On the mechanism of populating 3p levels of neon under pumping by a hard ioniser

    SciTech Connect

    Khasenov, M U

    2011-03-31

    The effect of quenching additives on the luminescence properties of helium - neon mixtures under pumping by {alpha} particles emitted from {sup 210}Po atoms is considered. It is concluded that, under excitation by a heavy charged particle, the population of the 3p'[1/2]{sub 0} level of neon is not related to the dissociative recombination of molecular ions. It is suggested that the most likely channels for populating the 3p level are the excitation transfer from metastable helium atoms to neon atoms and direct excitation of neon by nuclear particles and secondary electrons. (lasers and active media)

  8. Theoretical energies for the n = 1 and 2 states of the helium isoelectronic sequence up to Z = 100

    NASA Technical Reports Server (NTRS)

    Drake, G. W.

    1988-01-01

    The unified method described previously for combining high-precision nonrelativistic variational calculations with relativistic and quantum electrodynamic corrections is applied to the 1s2 1S0, 1s2s 1S0, 1s2s 1S0, 1s2s 3S1, 1s2p 1P1, and 1s2p 3P(0.1,2) states of helium-like ions. Detailed tabulations are presented for all ions in the range Z = 2-100 and are compared with a wide range of experimental data up to (Kr-34)+. The results for (U-90)+ significantly alter the recent Lamb shift measurement of Munger and Gould (1986) from 70.4 + or - 8.3 to 71.0 + or - 8.3 eV, in comparison with a revised theoretical value of 74.3 + or - 0.4 eV. The improved agreement is due to the inclusion of higher order two-electron corrections in the present work.

  9. Contribution of the 4 f -core-excited states in determination of atomic properties in the Promethium Isoelectronic Sequence

    NASA Astrophysics Data System (ADS)

    Beiersdorfer, Peter; Safronova, U. I.; Safronova, A. S.

    2014-05-01

    The atomic properties of Pm-like ions were comprehensively studied using relativistic atomic codes with the main emphasis on W ion. Excitation energies of the 4f14 nl (with nl = 5 s , 6 s , 5 p , 6 p , 5 d , 6 d , and 5 f) states in Pm-like ions with nuclear charge Z ranging from 74 to 100 are evaluated within the framework of relativistic many-body theory (RMBPT). First- and second-order Coulomb energies and first- and second-order Breit corrections to the energies are calculated. The important question of what is the ground state in Pm-like ions was answered. Properties of the 4 f -core-excited states are evaluated using the multiconfiguration relativistic Hebrew University Lawrence Livermore Atomic Code (HULLAC code) and the Hartree-Fock-Relativistic method (COWAN code). Our large scale calculations includes the following set of configurations: 4f14 5 s , 4f14 5 p , 4f13 5s2 , 4f13 5p2 , 4f13 5 s 5 p , 4f12 5s2 5 p , 4f12 5 s 5p2 , and 4f12 5p3 . Excitation energies, transition rates, and lifetimes in Pm-like tungsten are evaluated with additional inclusion of the 4f11 5s2 5p2 , 4f11 5 s 5p3 , 4f10 5s2 5p3 , and 4f10 5 s 5p4 configurations. Wavelengths of the 5 s - 5 p transitions are obtained by the COWAN, HULLAC, and RMBPT codes. This research was sponsored by DOE under the OFES grant DE-FG02-08ER54951 and in part by NNSA Cooperative Agreement DE-NA0001984. Work at Lawrence Livermore National Lab. was performed under the auspices of DOE under Contract DE-AC52-07NA27344.

  10. Photoionization of ions of the nitrogen isoelectronic sequence:experiment and theory for F2+ and Ne3+

    SciTech Connect

    Aguilar, A.; Emmons, E.D.; Gharaibeh, M.F.; Covington, A.M.; Bozek, J.D.; Ackerman, G.; Canton, S.; Rude, B.; Schlachter, A.S.; Hinojosa, G.; Alvarez, I.; Cisneros, C.; McLaughlin, B.M.; Phaneuf, R.A.

    2005-06-21

    Absolute photoionization measurements are reported for admixtures of the ground and metastable states of F2+ from 56.3 eV to 75.6 eV, and of Ne3+ from 89.3 eV to 113.8 eV. The 4So ground-state and the 2Do and 2Po metastable-state fractions present in the primary ion beams were estimated from photo ion yield measurements near the irrespective threshold energies. Most of the observed resonance structure has been spectroscopically assigned. The measurements are compared with new R-matrix theoretical calculations and with those in the TOP base astrophysical database. The systematic behaviour of the quantum-defect parameter is analyzed as a function of the nuclear charge for four Rydberg series observed in both species, and compared to published data for O+ and N.

  11. Higher order two- and three-body dispersion coefficients for alkali isoelectronic sequences by a variationally stable procedure

    NASA Astrophysics Data System (ADS)

    Huang, Shi-Zhong; Sun, Qiu-Feng

    2011-04-01

    Using the variationally stable method of Gao and Starace, and the simple ground state wave function of the valence electron previously suggested by Patil and Tang, the multipolar polarizabilities of Li, Na, K, Rb, Cs, Be+, Mg+, Ca+, Sr+, Ba+, the two-body dispersion coefficients of homonuclear and heteronuclear interactions from C6 to C40, as well as the three-body dispersion coefficients Z(L1, L2, L3) (up to Li = 5), are investigated. Higher order van der Waals dispersion coefficients Cn (n > 24) and Z(L1, L2, L3) (Li > 3) are reported for the first time. Comparisons with previous calculations found in the literature show that this approach is capable of yielding precise and fast convergent values for higher order dispersion coefficients for alkali-metal atoms.

  12. Antiferromagnetism and hidden order in isoelectronic doping of URu2Si2

    SciTech Connect

    Wilson, Murray N.; Williams, Travis J.; Cai, Yipeng; Hallas, Alannah M.; Medina, Teresa; Munsie, Timothy J.; Cheung, Sky C.; Frandsen, Benjamin A.; Liu, Lian; Uemura, Yasutomo J.; Luke, Graeme M.

    2016-02-01

    In this paper, we present muon spin rotation (mu SR) and susceptibility measurements on single crystals of isoelectronically doped URu2-xTxSi2 (T = Fe, Os) for doping levels up to 50%. Zero field (ZF) μ SR measurements show long-lived oscillations demonstrating that an antiferromagnetic state exists down to low doping levels for both Os and Fe dopants. The measurements further show an increase in the internal field with doping for both Fe and Os. Comparison of the local moment-hybridization crossover temperature from susceptibility measurements and our magnetic transition temperature shows that changes in hybridization, rather than solely chemical pressure, are important in driving the evolution of magnetic order with doping.

  13. Ab initio calculation of infrared intensities for the linear isoelectronic series HCN, HNC, CO, HCO/+/, and HOC/+/. [in interstellar medium

    NASA Technical Reports Server (NTRS)

    Rogers, J. D.; Hillman, J. J.

    1982-01-01

    Ab initio infrared intensities and dipole moment derivatives expressed in atomic polar tensor form are calculated using the 4-31 and 6-31G(double asterisk) basis sets for the isoelectronic HCN, HNC, CO, HCO(+), and HOC(+) series of molecules. The calculated atomic polar tensors are analyzed in terms of the charge-charge flux-overlap model, which is found to be useful in explaining some of the trends observed in the dipole moment derivatives for this series of molecules. A detailed examination of the dipole moment derivatives for the structural isomers indicates some of the ways in which experimental atomic polar tensors for one isomer should be modified to predict infrared intensities for the other isomer. The absolute intensities calculated for the HCO(+) and HOC(+) ions are believed to be accurate to within a factor of 2 and thus should be useful in astrophysical applications.

  14. High-Fidelity and Ultrafast Initialization of a Hole Spin Bound to a Te Isoelectronic Center in ZnSe

    NASA Astrophysics Data System (ADS)

    St-Jean, P.; Éthier-Majcher, G.; André, R.; Francoeur, S.

    2016-10-01

    We demonstrate the optical initialization of a hole-spin qubit bound to an isoelectronic center (IC) formed by a pair of Te impurities in ZnSe, an impurity-host system providing high optical homogeneity, large electric dipole moments, and potentially advantageous coherence times. The initialization scheme is based on the spin-preserving tunneling of a resonantly excited donor-bound exciton to a positively charged Te IC, thus forming a positive trion. The radiative decay of the trion within less than 50 ps leaves a heavy hole in a well-defined polarization-controlled spin state. The initialization fidelity exceeds 98.5% for an initialization time of less than 150 ps.

  15. Divergent Coupling of Alcohols and Amines Catalyzed by Isoelectronic Hydride Mn(I) and Fe(II) PNP Pincer Complexes.

    PubMed

    Mastalir, Matthias; Glatz, Mathias; Gorgas, Nikolaus; Stöger, Berthold; Pittenauer, Ernst; Allmaier, Günter; Veiros, Luis F; Kirchner, Karl

    2016-08-22

    Herein, we describe an efficient coupling of alcohols and amines catalyzed by well-defined isoelectronic hydride Mn(I) and Fe(II) complexes, which are stabilized by a PNP ligand based on the 2,6-diaminopyridine scaffold. This reaction is an environmentally benign process implementing inexpensive, earth-abundant non-precious metal catalysts, and is based on the acceptorless alcohol dehydrogenation concept. A range of alcohols and amines including both aromatic and aliphatic substrates were efficiently converted in good to excellent isolated yields. Although in the case of Mn selectively imines were obtained, with Fe-exclusively monoalkylated amines were formed. These reactions proceed under base-free conditions and required the addition of molecular sieves.

  16. Correlating the optical properties of WS2 monolayers grown by CVD with isoelectronic Mo doping level(Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Wang, Kai; Cross, Nick; Boulesbaa, Abdelaziz; Pudasaini, Pushpa R.; Tian, Mengkun; Mahjouri-Samani, Masoud; Oxley, Mark P.; Rouleau, Christopher M.; Puretzky, Alexander A.; Rack, Philip D.; Xiao, Kai; Yoon, Mina; Eres, Gyula; Duscher, Gerd; Geohegan, David B.

    2017-02-01

    Incorporating dopants in monolayer transition metal dichalcogenides (TMD) can enable manipulations of their electrical and optical properties. Previous attempts in amphoteric doping in monolayer TMDs have proven to be challenging. Here we report the incorporation of molybdenum (Mo) atoms in monolayer WS2 during growth by chemical vapor deposition, and correlate the distribution of Mo atoms with the optical properties including photoluminescence and ultrafast transient absorption dynamics. Dark field scanning transmission electron microscopy imaging quantified the isoelectronic doping of Mo in WS2 and revealed its gradual distribution along a triangular WS2 monolayer crystal, increasing from 0% at the edge to 2% in the center of the triangular WS2 triangular crystals. This agrees well with the Raman spectra data that showed two obvious modes between 360 cm-1 and 400 cm-1 that corresponded to MoS2 in the center. This in-plane gradual distribution of Mo in WS2 was found to account for the spatial variations in photoluminescence intensity and emission energy. Transition absorption spectroscopy further indicated that the incorporation of Mo in WS2 regulate the amplitude ratio of XA and XB of WS2. The effect of Mo incorporation on the electronic structure of WS2 was further elucidated by density functional theory. Finally, we compared the electrical properties of Mo incorporated and pristine WS2 monolayers by fabricating field-effect transistors. The isoelectronic doping of Mo in WS2 provides an alternative approach to engineer the bandgap and also enriches our understanding the influence of the doping on the excitonic dynamics.

  17. Application of a pulse-discharge helium detector to the determination of neon in air and water.

    PubMed

    Lasa, J; Mochalski, P; Lokas, E; Kedzior, L

    2002-08-30

    A pulse-discharge helium detector (Valco, PD-D2-I) is used to measure neon concentrations in air and water. The detection level is 0.5 x 10(-8) g/cm3 (0.2 ppm). Discharge gas doped with neon results in a linear response to the neon mass up to 10(-6) g. For measuring the neon concentration in water, a simple enrichment system is used.

  18. DETERMINATION OF THE SOLUBILITY OF NEON IN WATER AND EXTRACTED HUMAN FAT.

    DTIC Science & Technology

    coefficient (alpha) for neon in water, olive oil , and extracted human fat. Essentially, the method consists of a double extraction of sample material that...observed Bunsen absorption coefficients supply new information on the solubility of neon in human fatty material, olive oil , and water. (Author)

  19. Expanding the Catalog: Considering the Importance of Carbon, Magnesium, and Neon in the Evolution of Stars and Habitable Zones

    NASA Astrophysics Data System (ADS)

    Truitt, Amanda; Young, Patrick A.

    2017-01-01

    Building on previous work, we have expanded our catalog of evolutionary models for stars with variable composition; here we present models for stars of mass 0.5–1.2 M⊙, at scaled metallicities of 0.1–1.5 Z⊙, and specific C/Fe, Mg/Fe, and Ne/Fe values of 0.58–1.72 C/Fe⊙, 0.54–1.84 Mg/Fe⊙, and 0.5–2.0 Ne/Fe⊙, respectively. We include a spread in abundance values for carbon and magnesium based on observations of their variability in nearby stars; we choose an arbitrary spread in neon abundance values commensurate with the range seen in other low Z elements due to the difficult nature of obtaining precise measurements of neon abundances in stars. As indicated by the results of Truitt et al., it is essential that we understand how differences in individual elemental abundances, and not just the total scaled metallicity, can measurably impact a star’s evolutionary lifetime and other physical characteristics. In that work, we found that oxygen abundances significantly impacted the stellar evolution; carbon, magnesium, and neon are potentially important elements to individually consider due to their relatively high (but also variable) abundances in stars. We present 528 new stellar main-sequence models, and we calculate the time-dependent evolution of the associated habitable zone boundaries for each based on mass, temperature, and luminosity. We also reintroduce the 2 Gyr “Continuously Habitable Zone” (CHZ2) as a useful tool to help gauge the habitability potential for a given planetary system.

  20. The NEON Science Commissioning Plan: Strategies for Confirming System Operation

    NASA Astrophysics Data System (ADS)

    Wirth, G. D.; Thorpe, A.; Buur, H.

    2015-12-01

    A transformation is underway in the field of ecological monitoring as compelling science questions motivate us to build ever-larger networks aiming to acquire uniform datasets over wide geographical ranges and long timescales. The National Ecological Observatory Network (NEON), currently under construction across the U.S., represents the most ambitious such effort to characterize ecology at the continental scale. When completed in 2017, NEON will begin a 30-year program to monitor the state of North American ecosystems at scores of independent sites by employing a combination of terrestrial and aquatic sensors, organismal, biogeochemical, and hydrological sampling conducted by field staff, and airborne remote-sensing imaging and spectroscopy. Simply building and bringing such complex, long-term monitoring networks online is, however, insufficient to produce a useful result: the science team must also confirm that the system fulfills its essential mission to generate accurate and uniform data from all sites over time. This is the role of Science Commissioning, the process which completes the construction stage by confirming that the system operates as designed before entering full operations. Ideally, Science Commissioning involves simply testing the completed system against all applicable science requirements. In the real world of large, complex networks, planners of Science Commissioning must grapple with several key questions: How can we verify that the measurements from a given subsystem reflect "truth"? How can we ensure that similar subsystems at different sites return equivalent results? How can we confirm that data from the same site remain comparable over long periods of time? How can we conduct meaningful tests on a large system in a reasonable amount of time and effort? We describe the specific strategies NEON is developing to meet these challenges and the implications for other large ecological monitoring networks.

  1. Atomistic simulations of tungsten surface evolution under low-energy neon implantation

    NASA Astrophysics Data System (ADS)

    Backman, Marie; Hammond, Karl D.; Sefta, Faiza; Wirth, Brian D.

    2016-04-01

    Tungsten is a candidate material for the divertor of fusion reactors, where it will be subject to a high flux of particles coming from the fusion plasma as well as a significant heat load. Under helium plasma exposure in fusion-reactor-like conditions, a nanostructured morphology is known to form on the tungsten surface in certain temperature and incident energy ranges, although the formation mechanism is not fully established. A recent experimental study (Yajima et al 2013 Plasma Sci. Technol. 15 282-6) using neon or argon exposure did not produce similar nanostructure. This article presents molecular dynamics simulations of neon implantation in tungsten aimed at investigating the surface evolution and elucidating the role of noble gas mass in fuzz formation. In contrast to helium, neon impacts can sputter both tungsten and previously implanted neon atoms. The shorter range of neon ions, along with sputtering, limit the formation of large bubbles and likely prevents nanostructure formation.

  2. Nonlinear dynamics modulation in a neon glow discharge plasma

    NASA Astrophysics Data System (ADS)

    Miller, Paul M.

    In dynamics modulation, two modes in a driven neon glow discharge alternate as the dominant mode as their response to the driving force alternates between spatiotemporal and temporal periodic pulling. This phenomenon was first noted by Koepke, Weltmann, and Selcher (Bull. Am. Phys. Soc. 40, 1716 (1995)), who saw two limited but representative cases and proposed a mechanism (Phys. Rev. E 62, 2773 (2000)) by which it occurs. The intent of this dissertation is to document experimentally and test the dynamics modulation mechanism they proposed. Using a new extension of a previous mathematical treatment of periodic pulling, the resulting experimental data are used to verify the predicted mechanism. A numerical model is also presented that reproduces the signature of dynamics modulation and further supports the validity of the mechanism. For two pairs of mode frequencies, three complete data series as driving frequency is increased are presented. Each of these data series shows the progression of the system from pure spatiotemporal behavior, through dynamics modulation, and ending at entrainment in the upper mode. Ionization wave modes are examined using time series recorded using a photodiode with a narrow band filter that selectively passes the primary neon spectral line at 640 nm. The system was periodically driven using a narrow-band ring dye laser tuned to a wavelength near the metastable neon transition at 588.35 nm. The amplitude of the driving force was decreased (increased) by tuning the laser away from (nearer to) the center of the neon line, while the driving frequency was controlled by an acousto-optic modulator chopping the laser beam at the desired frequency. Arnol'd tongue boundaries identifying the edges of frequency entrainment regions in the driving amplitude-driving frequency plane were established for four different discharge currents. The (upward) dynamics modulation behavior seen by Koepke, Weltmann, and Selcher was reproduced and additional data

  3. Optimizing Sampling Efficiency for Biomass Estimation Across NEON Domains

    NASA Astrophysics Data System (ADS)

    Abercrombie, H. H.; Meier, C. L.; Spencer, J. J.

    2013-12-01

    Over the course of 30 years, the National Ecological Observatory Network (NEON) will measure plant biomass and productivity across the U.S. to enable an understanding of terrestrial carbon cycle responses to ecosystem change drivers. Over the next several years, prior to operational sampling at a site, NEON will complete construction and characterization phases during which a limited amount of sampling will be done at each site to inform sampling designs, and guide standardization of data collection across all sites. Sampling biomass in 60+ sites distributed among 20 different eco-climatic domains poses major logistical and budgetary challenges. Traditional biomass sampling methods such as clip harvesting and direct measurements of Leaf Area Index (LAI) involve collecting and processing plant samples, and are time and labor intensive. Possible alternatives include using indirect sampling methods for estimating LAI such as digital hemispherical photography (DHP) or using a LI-COR 2200 Plant Canopy Analyzer. These LAI estimations can then be used as a proxy for biomass. The biomass estimates calculated can then inform the clip harvest sampling design during NEON operations, optimizing both sample size and number so that standardized uncertainty limits can be achieved with a minimum amount of sampling effort. In 2011, LAI and clip harvest data were collected from co-located sampling points at the Central Plains Experimental Range located in northern Colorado, a short grass steppe ecosystem that is the NEON Domain 10 core site. LAI was measured with a LI-COR 2200 Plant Canopy Analyzer. The layout of the sampling design included four, 300 meter transects, with clip harvests plots spaced every 50m, and LAI sub-transects spaced every 10m. LAI was measured at four points along 6m sub-transects running perpendicular to the 300m transect. Clip harvest plots were co-located 4m from corresponding LAI transects, and had dimensions of 0.1m by 2m. We conducted regression analyses

  4. In situ measurements of neon in the thermosphere

    NASA Technical Reports Server (NTRS)

    Potter, W. E.; Kayser, D. C.

    1976-01-01

    The open source neutral mass spectrometer on the Atmosphere Explorer-C satellite has measured neon in the thermosphere. The absolute density of Ne is close to that predicted by using the ground level fraction by volume of Ne along with the assumption of diffusive equilibrium above 100 km. Data is presented for both geomagnetically quiet and disturbed circular orbits. At 290 km, a typical low latitude value of Ne is 3.0 x 10 to the 4th/cu cm. At this altitude Ne appears to be predominantly controlled by temperature except during magnetic disturbances, when offsetting forces due to wind systems may be present.

  5. Noble gases in diamonds - Occurrences of solarlike helium and neon

    NASA Technical Reports Server (NTRS)

    Honda, M.; Reynolds, J. H.; Roedder, E.; Epstein, S.

    1987-01-01

    Seventeen diamond samples from diverse locations were analyzed for the contents of He, Ar, Kr, and Xe, and of their isotopes, using a Reynolds (1956) type glass mass spectrometer. The results disclosed a large spread in the He-3/He-4 ratios, ranging from values below atmospheric to close to the solar ratio. In particular, solarlike He-3/He-4 ratios were seen for an Australian colorless diamond composite and an Arkansas diamond, which also displayed solarlike neon isotopic ratios. Wide variation was also observed in the He-4/Ar-40 ratios, suggesting a complex history for the source regions and the diamond crystallization processes.

  6. The abundances of neon, sulfur, and argon in planetary nebulae

    NASA Technical Reports Server (NTRS)

    Beck, S. C.; Lacy, J. H.; Townes, C. H.; Aller, L. H.; Geballe, T. R.; Baas, F.

    1981-01-01

    New infrared observations of Ne II, Ar III, and S IV are used in optical observations of other ionization states of the considered elements to evaluate the abundances of neon, argon, and sulfur in 18 planetary nebulae. Attention is also given to one or more of the infrared lines in 18 other nebulae. It is pointed out that S IV was detected in approximately 90% of the observed objects, while Ar III was found in about 80%, and Ne II in roughly one-third. It is noted that optical observations typically include only a limited region of the nebula, while the infrared measurements frequently involve integration over the entire nebular image.

  7. Cutaneous Ossifying Fibroma in a Neon Tetra (Paracheirodon innesi).

    PubMed

    Murphy, B; Imai, D M

    2016-01-01

    A cutaneous proliferative mass was identified arising from the caudal peduncle of a captive neon tetra fish (Paracheirodon innesi). The lesion was histologically consistent with an ossifying fibroma (OF), a fibro-osseous proliferative lesion typically identified in the jaws or tooth-associated supportive tissues of mammals. Although it has been previously reported, there is no recent report of this lesion occurring in a fish. This is the first report of a cutaneous ossifying fibroma in a characin fish. The authors speculate on the pathogenesis of this lesion, which may have arisen from the scale-associated mesenchymal tissues. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Expected intensities of solar neon-like ions

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.; Kastner, S. O.

    1985-01-01

    A study of the expected intensities of the stronger solar neon-like ion emission lines, some not yet observed, is carried out to compare with the observational situation. The potential usefulness of the 2p5 3s(3P2) - 2p6 forbidden line as a density diagnostic is discussed, and new electric quadrupole lines in the soft X-ray range are noted. 'Observability diagrams' are presented as a convenient overview of the known and unobserved lines. The S VII resonance lines appear to have anomalous intensities.

  9. Noble gases in diamonds - Occurrences of solarlike helium and neon

    NASA Technical Reports Server (NTRS)

    Honda, M.; Reynolds, J. H.; Roedder, E.; Epstein, S.

    1987-01-01

    Seventeen diamond samples from diverse locations were analyzed for the contents of He, Ar, Kr, and Xe, and of their isotopes, using a Reynolds (1956) type glass mass spectrometer. The results disclosed a large spread in the He-3/He-4 ratios, ranging from values below atmospheric to close to the solar ratio. In particular, solarlike He-3/He-4 ratios were seen for an Australian colorless diamond composite and an Arkansas diamond, which also displayed solarlike neon isotopic ratios. Wide variation was also observed in the He-4/Ar-40 ratios, suggesting a complex history for the source regions and the diamond crystallization processes.

  10. Neon Isotope Fractionation in Ice Cores at Close-Off Depth

    NASA Astrophysics Data System (ADS)

    Liang, C.; Severinghaus, J. P.

    2015-12-01

    Analyzing trapped air bubbles in glacial ice is a well-established and useful method to reconstruct past atmospheric gas concentrations. However, trapped gas composition can be affected by fractionation during the closure of the air bubbles, complicating the reconstruction. Gases such as dioxygen (O2) and dihydrogen (H2) are known to leak out of the bubbles by permeation through the ice lattice at the close-off depth,where firn turns into ice. This process also can cause isotope fractionation, which obscures the past atmospheric isotope ratios in air bubbles in glacial ice. In order to establish the most accurate measurements of past atmospheric content, we need very detailed understanding of the permeation leakage mechanism in order to establish possible corrections. In this study, we propose the use of neon stable isotopes (neon-22 and neon-20) to place constraints on the mechanism of permeation leakage. Neon isotopes are an ideal system to explore because neon has a constant atmospheric isotope ratio, and thus only is affected by close-off fractionation. Neon permeation occurs via velocity-dependent hopping between sites within the ice lattice, because the neon atom is smaller than the critical size (3.6 Å) of the opening in the lattice. Theory predicts that neon isotope fractionation will occur due to the lower velocity of the heavier isotope, but this has never been experimentally verified and the theory is unable to quantitatively predict the magnitude of the fractionation. We will present the first results of high-precision neon isotope (22Ne/20Ne) measurements made in air pumped from the firm-to-ice transition in the Greenland Ice Sheet, where actively closing air bubbles drive permeation leakage. By measuring this natural neon isotope fractionation, we hope to learn about the mass dependence of the leakage mechanism and develop a more quantitative theory that is generalizable to biogeochemically- and climatically-active gases.

  11. The Bright Fluorescent Protein mNeonGreen Facilitates Protein Expression Analysis In Vivo

    PubMed Central

    Hostettler, Lola; Grundy, Laura; Käser-Pébernard, Stéphanie; Wicky, Chantal; Schafer, William R.; Glauser, Dominique A.

    2017-01-01

    The Green Fluorescent Protein (GFP) has been tremendously useful in investigating cell architecture, protein localization, and protein function. Recent developments in transgenesis and genome editing methods now enable working with fewer transgene copies and, consequently, with physiological expression levels. However, lower signal intensity might become a limiting factor. The recently developed mNeonGreen protein is a brighter alternative to GFP in vitro. The goal of the present study was to determine how mNeonGreen performs in vivo in Caenorhabditis elegans—a model used extensively for fluorescence imaging in intact animals. We started with a side-by-side comparison between cytoplasmic forms of mNeonGreen and GFP expressed in the intestine, and in different neurons, of adult animals. While both proteins had similar photostability, mNeonGreen was systematically 3–5 times brighter than GFP. mNeonGreen was also used successfully to trace endogenous proteins, and label specific subcellular compartments such as the nucleus or the plasma membrane. To further demonstrate the utility of mNeonGreen, we tested transcriptional reporters for nine genes with unknown expression patterns. While mNeonGreen and GFP reporters gave overall similar expression patterns, low expression tissues were detected only with mNeonGreen. As a whole, our work establishes mNeonGreen as a brighter alternative to GFP for in vivo imaging in a multicellular organism. Furthermore, the present research illustrates the utility of mNeonGreen to tag proteins, mark subcellular regions, and describe new expression patterns, particularly in tissues with low expression. PMID:28108553

  12. Evaluation of a pulse-discharge helium ionisation detector for the determination of neon concentrations by gas chromatography.

    PubMed

    Lasa, J; Mochalski, P; Pusz, J

    2004-05-07

    A pulse-discharge helium ionisation detector, PDHID (Valco, PD-D2-I) with sample introduced to the discharge zone is shown to be applicable for reliable determinations of neon by gas chromatography. The detection level of 80 pg was obtained, but the dependence between detector response and neon mass was non-linear. However, for the discharge gas doped with 33 ppm of neon, a linear response to the neon mass up to 10(-5) g and the detection level of 0.5 ng were obtained. The method can be used for measuring neon concentrations in groundwater systems for hydrogeological purposes.

  13. Infrared spectra of small molecular ions trapped in solid neon

    SciTech Connect

    Jacox, Marilyn E.

    2015-01-22

    The infrared spectrum of a molecular ion provides a unique signature for that species, gives information on its structure, and is amenable to remote sensing. It also serves as a comparison standard for refining ab initio calculations. Experiments in this laboratory trap molecular ions in dilute solid solution in neon at 4.2 K in sufficient concentration for observation of their infrared spectra between 450 and 4000 cm{sup !1}. Discharge-excited neon atoms produce cations by photoionization and/or Penning ionization of the parent molecule. The resulting electrons are captured by other molecules, yielding anions which provide for overall charge neutrality of the deposit. Recent observations of ions produced from C{sub 2}H{sub 4} and BF{sub 3} will be discussed. Because of their relatively large possibility of having low-lying excited electronic states, small, symmetric molecular cations are especially vulnerable to breakdown of the Born-Oppenheimer approximation. Some phenomena which can result from this breakdown will be discussed. Ion-molecule reaction rates are sufficiently high that in some systems absorptions of dimer cations and anions are also observed. When H{sub 2} is introduced into the system, the initially-formed ion may react with it. Among the species resulting from such ion-molecule reactions that have recently been studied are O{sub 4}{sup +}, NH{sub 4}{sup +}, HOCO{sup +}, and HCO{sub 2}{sup !}.

  14. Helium-neon laser treatment transforms fibroblasts into myofibroblasts.

    PubMed Central

    Pourreau-Schneider, N.; Ahmed, A.; Soudry, M.; Jacquemier, J.; Kopp, F.; Franquin, J. C.; Martin, P. M.

    1990-01-01

    The differentiation of myofibroblastic cells from normal human gingival fibroblasts in vitro has been established by transmission electron microscopy and quantitated by immunohistochemistry, using antigelsolin monoclonal antibodies. Untreated control cultures were compared to cultures exposed to Helium-Neon (He-Ne) laser irradiation. A direct and massive transformation of the cultured fibroblasts into myofibroblasts was observed as early as 24 hours after laser treatment, whereas control cultures were comprised of only resting fibroblasts and active fibroblasts. This in vitro induction of myofibroblasts may be analogous to that which occurs in vivo. Therefore we undertook a similar study using biopsies from gingival tissues after wisdom tooth extraction. Myofibroblasts were present in the connective tissue of laser-treated gums 48 hours after irradiation, but not in untreated contralateral control tissues. These data provide evidence that the primary biologic effect of the Helium-Neon laser on connective tissue is the rapid generation of myofibroblasts from fibroblasts. The induction of a phenotype with contractile properties may have clinical significance in the acceleration of the wound-healing process. Images Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:2372040

  15. Production rates of neon xenon isotopes by energetic neutrons

    NASA Technical Reports Server (NTRS)

    Leich, D. A.; Borg, R. J.; Lanier, V. B.

    1986-01-01

    As a first step in an experimental program to study the behavior of noble gases produced in situ in minerals, a suite of minerals and pure chemicals were irradiated with 14.5 MeV neutrons at LLNL's Rotating Target Neutron Source (RTNS-II) and production rates for noble gases were determined. While neutron effects in meteorites and lunar samples are dominated by low-energy neutron capture, more energetic cosmic-ray secondary neutrons can provide significant depth-dependent contributions to production of cosmogenic nuclides through endothermic reactions such as (n,2n), (n,np), (n,d) and (n,alpha). Production rates for nuclides produced by cosmic-ray secondary neutrons are therefore useful in interpreting shielding histories from the relative abundances of cosmogenic nuclides. Absolute production cross sections were calculated from isotope dilution analyses of NaCl, Mg, CsCl, and Ba(NO3)2 samples, assuming purity, stoichiometry, and quantitative noble gas retention and extraction. Relative production cross sections determined from neon isotopic ratios in the mineral samples were also considered in evaluating the neon production cross sections. Results are presented.

  16. Reaction times to neon, LED, and fast incandescent brake lamps.

    PubMed

    Sivak, M; Flannagan, M J; Sato, T; Traube, E C; Aoki, M

    1994-06-01

    Standard incandescent brake lamps have a relatively slow rise time. It takes approximately a quarter of a second for them to reach 90% of asymptotic light output, causing potential delays in responses by following drivers. The present study evaluated reaction times to brake signals from standard incandescent brake lamps and from three alternative brake lamps with substantially faster rise times: neon, LED, and fast incandescent. The study, performed in a laboratory, simulated a daytime driving condition. The subject's task was to respond as quickly as possible to the onset of either of two brake lamps in the visual periphery, while engaged in a central tracking task. Brake signals were presented at two levels of luminous intensity. The results showed that reaction times to the alternative brake lamps were faster than to the standard incandescent lamp, with the advantage averaging 166 ms for the LED and neon lamps, and 135 ms for the fast incandescent lamp. A reduction of the signals' luminous intensity from 42 cd to 5 cd increased the reaction time by 84 ms.

  17. Benchmark values of chemical potential and chemical hardness for atoms and atomic ions (including unstable anions) from the energies of isoelectronic series.

    PubMed

    Cárdenas, Carlos; Heidar-Zadeh, Farnaz; Ayers, Paul W

    2016-09-14

    We present benchmark values for the electronic chemical potential and chemical hardness from reference data for ionization potentials and electron affinities. In cases where the energies needed to compute these quantities are not available, we estimate the ionization potential of the metastable (di)anions by extrapolation along the isoelectronic series, taking care to ensure that the extrapolated data satisfy reasonable intuitive rules to the maximum possible extent. We also propose suitable values for the chemical potential and chemical hardness of zero-electron species. Because the values we report are faithful to the trends in accurate data on atomic energies, we believe that our proposed values for the chemical potential and chemical hardness are ideally suited to conceptual studies of chemical trends across the periodic table. The critical nuclear charge (Z critical) of the isoelectronic series with 2 < N < 96 has also been reported for the first time.

  18. Effect of hot implantation on ON-current enhancement utilizing isoelectronic trap in Si-based tunnel field-effect transistors

    NASA Astrophysics Data System (ADS)

    Mori, Takahiro; Mizubayashi, Wataru; Morita, Yukinori; Migita, Shinji; Fukuda, Koichi; Miyata, Noriyuki; Yasuda, Tetsuji; Masahara, Meishoku; Ota, Hiroyuki

    2015-03-01

    A tunneling-current enhancement technology for Si-based tunnel field-effect transistors (TFETs) utilizing an Al-N isoelectronic trap (IET) has been proposed recently. In this study, we investigate hot implantation as a doping technique for Al-N isoelectronic impurity. Hot implantation reduces the damage induced by Al and N implantation processes, resulting in performance improvement of IET-assisted TFETs, e.g., a 12-fold enhancement in the driving current at an operation voltage of 0.5 V and an approximately one-third reduction in the subthreshold slope. By hot implantation, we can achieve a higher driving current in Si-based TFETs using the IET technology.

  19. Isoelectronic substitution from Si52- to Al5H52-: Exploration of the series Si5-n(AlH)n2- (n = 0-5)

    NASA Astrophysics Data System (ADS)

    Fuenzalida-Valdivia, Isabel; Beltran, Maria J.; Ferraro, Franklin; Vasquez-Espinal, Alejandro; Tiznado, William; Osorio, Edison

    2016-03-01

    We established that the transformation from Si52- to Al5H52- could be possible by the successive isoelectronic substitution of silicon atoms by Alsbnd H units. The potential energy surfaces for the series Si5-n(AlH)n2- (n = 0-5) systems were explored in detail, and the global minima maintained the same overall deltahedral structure as the one of the Si52- cluster. The conservation of the overall structure upon isoelectronic substitution was proven to happen due to the preservation of the chemical bonding pattern. Theoretical VDEs were calculated for the series LiSi5-n(AlH)n- (n = 1-4) systems to facilitate their experimental detection.

  20. NEON: Transforming Environmental Data into Free, Open Information

    NASA Astrophysics Data System (ADS)

    Wee, B.

    2010-12-01

    The National Ecological Observatory Network (NEON) will collect data across the United States on the impacts of climate change, land use change and invasive species on natural resources and biodiversity. NEON is a project of the U.S. National Science Foundation (NSF), with many other U.S. agencies and NGOs cooperating. The Observatory’s construction plans call for 60 sites distributed across 20 ecoclimatic Domains. Data will be collected from strategically selected sites within each Domain and synthesized into information products that can be used to describe changes in the nation’s ecosystem through space and time. Sites are arrayed across different land-use types in order to understand large-scale environmental drivers affect biodiversity, ecohydrology, biogeochemistry, and disease ecology across the US continent. NEON is an instrument that listens to the pulse of the US continental ecosystem: infrastructure deployed at these sites will collect an average of over 500 primary measurements at each site, including annual high-resolution airborne LiDAR and hyperspectral data. These primary measurements will be transformed by a state-of-the-art cyberinfrastruture into over 100 higher-order data products. All measurements, data products, algorithms used to compute the data products, and protocols used to collect the primary measurements will be freely available to the public and assessable over the internet. The information products, including selected socio-economic datasets from cooperating Federal agencies, will be served in standard formats, grid-sizes, and geographical projections. This type of information is anticipated to have a wide range of uses, including ecological forecasting, education, public engagement, socio-economic analyses, decision support for climate-change adaptation and mitigation, resource management, and environmental risk management. Open data, interoperability, an open and integrated observation infrastructure, public engagement, and a

  1. NEON, Establishing a Standardized Network for Groundwater Observations

    NASA Astrophysics Data System (ADS)

    Fitzgerald, M.; Schroeter, N.; Goodman, K. J.; Roehm, C. L.

    2013-12-01

    The National Ecological Observatory Network (NEON) is establishing a standardized set of data collection systems comprised of in-situ sensors and observational sampling to obtain data fundamental to the analysis of environmental change at a continental scale. NEON will be collecting aquatic, terrestrial, and atmospheric data using Observatory-wide standardized designs and methods via a systems engineering approach. This approach ensures a wealth of high quality data, data algorithms, and models that will be freely accessible to all communities such as academic researchers, policy makers, and the general public. The project is established to provide 30 years of data which will enable prediction and forecasting of drivers and responses of ecological change at scales ranging from localized responses through regional gradients and up to the continental scale. The Observatory is a distributed system of sites spread across the United States, including Alaska, Hawaii, and Puerto Rico, which is subdivided into 20 statistically unique domains, based on a set of 18 ecologically important parameters. Each domain contains at least one core aquatic and terrestrial site which are located in unmanaged lands, and up to 2 additional sites selected to study domain specific questions such as nitrogen deposition gradients and responses of land use change activities on the ecosystem. Here, we present the development of NEON's groundwater observation well network design and the timing strategy for sampling groundwater chemistry. Shallow well networks, up to 100 feet in depth, will be installed at NEON aquatic sites and will allow for observation of localized ecohydrologic site conditions, by providing basic spatio-temporal near-real time data on groundwater parameters (level, temperature, conductivity) collected from in situ high-resolution instrumentation positioned in each well; and biannual sampling of geochemical and nutrient (N and P) concentrations in a subset of wells for each

  2. Predicting helium and neon adsorption and separation on carbon nanotubes by Monte Carlo simulation.

    PubMed

    Bolboli Nojini, Zabiollah; Abbas Rafati, Amir; Majid Hashemianzadeh, Seyed; Samiee, Sepideh

    2011-04-01

    The adsorption of helium and neon mixtures on single-walled carbon nanotubes (SWCNTs) was investigated at various temperatures (subcritical and supercritical) and pressures using canonical Monte Carlo (CMC) simulation. Adsorption isotherms were obtained at different temperatures (4, 40, 77 and 130 K) and pressures ranging from 1 to 16 MPa. Separation factors and isosteric enthalpies of adsorption were also calculated. Moreover, the adsorption isotherms were obtained at constant specific temperatures (4 and 40 K) and pressures (0.2 and 1.0 MPa) as a function of the amount adsorbed. All of the adsorption isotherms for an equimolar mixture of helium and neon have a Langmuir shape, indicating that no capillary condensation occurs. Both the helium and the neon adsorption isotherms exhibit similar behavior, and slightly more of the helium and neon mixture is adsorbed on the inner surfaces of the SWCNTs than on their outer surfaces. More neon is adsorbed than helium within the specified pressure range. The data obtained show that the isosteric enthalpies for the adsorption of neon are higher than those for helium under the same conditions, which means that adsorption of neon preferentially occurs by (15, 15) SWCNTs. Furthermore, the isosteric enthalpies of adsorption of both gases decrease with increasing temperature.

  3. Revisitation of the luminance conditions for the occurrence of the achromatic neon color spreading illusion.

    PubMed

    Bressan, P

    1993-07-01

    This paper develops the idea (Bressan, 1993) that neon spreading derives from the perceptual scissioning of ordinary assimilation color, a process identical to that occurring with nonillusory colors in phenomenal transparency. It is commonly held that the critical elements in achromatic neon spreading patterns must be of luminance intermediate between that of the embedding lines and of the background. The interpretation of neon spreading on the basis of color scissioning, however, predicts that neon spreading should also be observed for different luminance hierarchies, provided that these are compatible with transparency. This prediction found experimental support in the present work. The results suggest that (1) the widespread notion that chromatic and achromatic neon spreading must be mediated by separate mechanisms is unwarranted; (2) the widespread notion that color spreading in ordinary assimilation patterns and color spreading in neon patterns must be mediated by separate mechanisms is unwarranted; and (3) other than pointing to the way in which the overall organization of a scene affects the mode of color appearance, the neon spreading effect may not convey any extra theoretical relevance.

  4. Cationic terminal gallylene complexes by halide abstraction: coordination chemistry of a valence isoelectronic analogue of CO and N2.

    PubMed

    Coombs, Natalie D; Vidovic, Dragoslav; Day, Joanna K; Thompson, Amber L; Le Pevelen, Delphine D; Stasch, Andreas; Clegg, William; Russo, Luca; Male, Louise; Hursthouse, Michael B; Willock, David J; Aldridge, Simon

    2008-11-26

    While N(2) and CO have played central roles in developing models of electronic structure, and their interactions with transition metals have been widely investigated, the valence isoelectronic diatomic molecules EX (E = group 13 element, X = group 17 element) have yet to be isolated under ambient conditions, either as the "free" molecule or as a ligand in a simple metal complex. As part of a program designed to address this deficiency, together with wider issues of the chemistry of cationic systems [L(n)M(ER)](+) (E = B, Al, Ga; R = aryl, amido, halide), we have targeted complexes of the type [L(n)M(GaX)](+). Halide abstraction is shown to be a viable method for the generation of mononuclear cationic complexes containing gallium donor ligands. The ability to isolate tractable two-coordinate products, however, is strongly dependent on the steric and electronic properties of the metal/ligand fragment. In the case of complexes containing ancillary pi-acceptor ligands such as CO, cationic complexes can only be isolated as base-trapped adducts, even with bulky aryl substituents at gallium. Base-free gallylene species such as [Cp*Fe(CO)(2)(GaMes)](+) can be identified only in the vapor phase by electrospray mass spectrometry experiments. With bis(phosphine) donor sets at the metal, the more favorable steric/electronic environment allows for the isolation of two-coordinate ligand systems, even with halide substituents at gallium. Thus, [Cp*Fe(dppe)(GaI)](+)[BAr(f)(4)](-) (9) can be synthesized and shown crystallographically to feature a terminally bound GaI ligand; 9 represents the first experimental realization of a complex containing a valence isoelectronic group 13/group 17 analogue of CO and N(2). DFT calculations reveal a relatively weakly bound GaI ligand, which is confirmed experimentally by the reaction of 9 with CO to give [Cp*Fe(dppe)(CO)](+)[BAr(f)(4)](-). In the absence of such reagents, 9 is stable for weeks in fluorobenzene solution, presumably reflecting (i

  5. Boronyl ligand as a member of the isoelectronic series BO(-) → CO → NO(+): viable cobalt carbonyl boronyl derivatives?

    PubMed

    Gong, Xiaoli; Li, Qian-Shu; Xie, Yaoming; King, R Bruce; Schaefer, Henry F

    2010-12-06

    Recently the first boronyl (oxoboryl) complex [(c-C(6)H(11))(3)P](2)Pt(BO)Br was synthesized. The boronyl ligand in this complex is a member of the isoelectronic series BO(-) → CO → NO(+). The cobalt carbonyl boronyls Co(BO)(CO)(4) and Co(2)(BO)(2)(CO)(7), with cobalt in the formal d(8) +1 oxidation state, are thus isoelectronic with the familiar homoleptic iron carbonyls Fe(CO)(5) and Fe(2)(CO)(9). Density functional theory predicts Co(BO)(CO)(4) to have a trigonal bipyramidal structure with the BO group in an axial position. The tricarbonyl Co(BO)(CO)(3) is predicted to have a distorted square planar structure, similar to those of other 16-electron complexes of d(8) transition metals. Higher energy Co(BO)(CO)(n) (n = 3, 2) structures may be derived by removal of one (for n = 3) or two (for n = 2) CO groups from a trigonal bipyramidal Co(BO)(CO)(4) structure. Structures with a CO group bridging 17-electron Co(CO)(4) and Co(BO)(2)(CO)(3) units and no Co-Co bond are found for Co(2)(BO)(2)(CO)(8). However, Co(2)(BO)(2)(CO)(8) is not viable because of the predicted exothermic loss of CO to give Co(2)(BO)(2)(CO)(7). The lowest lying Co(2)(BO)(2)(CO)(7) structure is a triply bridged (2BO + CO) structure closely related to the experimental Fe(2)(CO)(9) structure. However, other relatively low energy Co(2)(BO)(2)(CO)(7) structures are found, either with a single CO bridge, similar to the experimental Os(2)(CO)(8)(μ-CO) structure; or with 17-electron Co(CO)(4) and Co(BO)(2)(CO)(3) units joined by a single Co-Co bond with or without semibridging carbonyl groups. Both triplet and singlet Co(2)(BO)(2)(CO)(6) structures are found. The lowest lying triplet Co(2)(BO)(2)(CO)(6) structures have a Co(CO)(3)(BO)(2) unit coordinated to a Co(CO)(3) unit through the oxygen atoms of the boronyl groups with a non-bonding ∼4.3 Å Co···Co distance. The lowest lying singlet Co(2)(BO)(2)(CO)(6) structures have either two three-electron donor bridging η(2)-μ-BO groups and no Co

  6. Isotopic effects in the neon fixed point: uncertainty of the calibration data correction

    NASA Astrophysics Data System (ADS)

    Steur, Peter P. M.; Pavese, Franco; Fellmuth, Bernd; Hermier, Yves; Hill, Kenneth D.; Seog Kim, Jin; Lipinski, Leszek; Nagao, Keisuke; Nakano, Tohru; Peruzzi, Andrea; Sparasci, Fernando; Szmyrka-Grzebyk, Anna; Tamura, Osamu; Tew, Weston L.; Valkiers, Staf; van Geel, Jan

    2015-02-01

    The neon triple point is one of the defining fixed points of the International Temperature Scale of 1990 (ITS-90). Although recognizing that natural neon is a mixture of isotopes, the ITS-90 definition only states that the neon should be of ‘natural isotopic composition’, without any further requirements. A preliminary study in 2005 indicated that most of the observed variability in the realized neon triple point temperatures within a range of about 0.5 mK can be attributed to the variability in isotopic composition among different samples of ‘natural’ neon. Based on the results of an International Project (EUROMET Project No. 770), the Consultative Committee for Thermometry decided to improve the realization of the neon fixed point by assigning the ITS-90 temperature value 24.5561 K to neon with the isotopic composition recommended by IUPAC, accompanied by a quadratic equation to take the deviations from the reference composition into account. In this paper, the uncertainties of the equation are discussed and an uncertainty budget is presented. The resulting standard uncertainty due to the isotopic effect (k = 1) after correction of the calibration data is reduced to (4 to 40) μK when using neon of ‘natural’ isotopic composition or to 30 μK when using 20Ne. For comparison, an uncertainty component of 0.15 mK should be included in the uncertainty budget for the neon triple point if the isotopic composition is unknown, i.e. whenever the correction cannot be applied.

  7. Theoretical Modeling of Radiation-driven Atomic Kinetics of a Neon Photoionized Plasma

    NASA Astrophysics Data System (ADS)

    Durmaz, Tunay

    We report on a theoretical study on atomic kinetics modeling of a photoionized neon plasma at conditions relevant to laboratory experiments performed at the Z-machine in Sandia National Laboratories. We describe an atomic kinetics model and code, ATOKIN, that was developed and used to compute the atomic level population distribution. The study includes atomic level sensitivity with respect to energy level structure, radiation and transient effects, electron temperature and x-ray drive sensitivity and an idea for electron temperature extraction from a level population ratio. The neon atomic model considers several ionization stages of highly-charged neon ions as well as a detailed structure of non-autoionizing and autoionizing energy levels in each ion. In the energy level sensitivity study, the atomic model was changed by adding certain types of energy levels such as singly-excited, auto-ionizing doubly-excited states. Furthermore, these levels were added ion by ion for the most populated ions. Atomic processes populating and de-populating the energy levels consider photoexcitation and photoionization due to the external radiation flux, and spontaneous and collisional atomic processes including plasma radiation trapping. Relevant atomic cross sections and rates were computed with the atomic structure and scattering FAC code. The calculations were performed at constant particle number density and driven by the time-histories of temperature and external radiation flux. These conditions were selected in order to resemble those achieved in photoionized plasma experiments at the Z facility of Sandia National Laboratories. For the same set of time histories, calculations were done in a full time-dependent mode and also as a sequence of instantaneous, steady states. Differences between both calculations are useful to identify transient effects in the ionization and atomic kinetics of the photoionized plasma, and its dependence on the atomic model and plasma environmental

  8. Mechanism of the tunable structural color of neon tetra

    NASA Astrophysics Data System (ADS)

    Yoshioka, Shinya

    2010-03-01

    Many examples of the structural color can be found in butterfly wings, beetle's elytra and bird feathers. Since the color-producing microstructures of these examples mainly consist of stable materials, for example, dried cuticles in insects and keratin and melanin granules in bird feathers, it is impossible to actively change the microstructure. On the other hand, some fish have the tunability in their structural colors. For example, a small tropical fish, neon tetra, has a longitudinal stripe that looks blue-green in the day time, while it changes into deep violet at night. This fact clearly indicates the variability in the microstructure. It is known that the iridophore of the stripe part of neon tetra contains two stacks of thin light-reflecting platelets that are made of guanine crystal. Since the arrangement of the platelets is observed periodic, the stack is thought to cause the structural color through the multilayer thin-film interference. Consequently, the variability in the color is thought to originate from the variation in the distance between the platelets. Two explanations have been proposed so far for the distance variation. Lythoge and Shand considered that the distance is controlled by osmotic pressure that induces the inflow of the water into the iridophore[1]. On the other hand, Nagaishi et al. proposed a different model, called Venetian blind model, in which the inclination angle of the platelets is varied, resulting in the change in the distance[2]. Recently, we have performed detailed optical measurements on the iridophore of neon tetra. We have paid particular attention to the direction of the reflected light, since the Venetian blind model expects that the direction varies with the color change owing to the tilt of the platelets. We present the experimental results and quantitatively discuss the validity of the Venetian blind model. [4pt] [1] J. N. Lythgoe, and J. Shand, J Physiol. 325, 23-34 (1982). [0pt] [2] H. Nagaishi, N. Oshima, and R

  9. On the origin of the differences in the Cu K-edge XANES of isostructural and isoelectronic compounds.

    PubMed

    Sipr, O; Rocca, F; Fornasini, P

    2009-06-24

    Cu K-edge x-ray absorption near-edge structure (XANES) spectra of trigonal (3R) CuScO(2) and CuLaO(2) and of hexagonal (2H) CuScO(2) were investigated experimentally and theoretically, in order to study differences between spectra of isostructural and isoelectronic compounds. Significant differences were found in the Cu K-edge XANES of 3R CuScO(2) and 3R CuLaO(2); these differences can be understood by considering the calculated polarization dependence of the XANES spectra and the differences between the phaseshifts of Sc and La. Spectra of the 3R and 2H polytypes of CuScO(2) differ only weakly and the difference originates from the long-range order. The pre-edge peak around 8980 eV is generated by the same mechanism as the pre-edge peak in Cu(2)O, i.e. involving scattering by the Cu atoms in the plane which is perpendicular to the O-Cu-O axis.

  10. Energy density functionals from the strong-coupling limit applied to the anions of the He isoelectronic series

    SciTech Connect

    Mirtschink, André; Gori-Giorgi, Paola; Umrigar, C. J.; Morgan, John D.

    2014-05-14

    Anions and radicals are important for many applications including environmental chemistry, semiconductors, and charge transfer, but are poorly described by the available approximate energy density functionals. Here we test an approximate exchange-correlation functional based on the exact strong-coupling limit of the Hohenberg-Kohn functional on the prototypical case of the He isoelectronic series with varying nuclear charge Z < 2, which includes weakly bound negative ions and a quantum phase transition at a critical value of Z, representing a big challenge for density functional theory. We use accurate wavefunction calculations to validate our results, comparing energies and Kohn-Sham potentials, thus also providing useful reference data close to and at the quantum phase transition. We show that our functional is able to bind H{sup −} and to capture in general the physics of loosely bound anions, with a tendency to strongly overbind that can be proven mathematically. We also include corrections based on the uniform electron gas which improve the results.

  11. A Comparison of Detailed Level and Superconfiguration Models of Neon

    SciTech Connect

    Hansen, S B; Fournier, K B; Bauche-Arnoult, C; Bauche, J; Peyrusse, O

    2005-01-03

    The superconfiguration (SC) approach to collisional-radiative modeling can significantly decrease the computational demands of finding non-LTE level populations in complex systems. However, it has not yet been fully determined whether the statistical averaging of SC models leads to a significant loss of accuracy. The present work compares results from two independent models: a detailed-level accounting (DLA) model based on HULLAC data and the SC model MOST. The relatively simple level structures of the K- and L-shell ions of the neon test system ensure a tractable number of levels in the DLA model but challenge the statistical assumptions of the SC approach. Nonetheless, we find fair agreement between the two models for average ion charges, SC populations, and various effective temperatures.

  12. Helium and neon abundances and compositions in cometary matter.

    PubMed

    Marty, Bernard; Palma, Russell L; Pepin, Robert O; Zimmermann, Laurent; Schlutter, Dennis J; Burnard, Peter G; Westphal, Andrew J; Snead, Christopher J; Bajt, Sasa; Becker, Richard H; Simones, Jacob E

    2008-01-04

    Materials trapped and preserved in comets date from the earliest history of the solar system. Particles captured by the Stardust spacecraft from comet 81P/Wild 2 are indisputable cometary matter available for laboratory study. Here we report measurements of noble gases in Stardust material. Neon isotope ratios are within the range observed in "phase Q," a ubiquitous, primitive organic carrier of noble gases in meteorites. Helium displays 3He/4He ratios twice those in phase Q and in Jupiter's atmosphere. Abundances per gram are surprisingly large, suggesting implantation by ion irradiation. The gases are probably carried in high-temperature igneous grains similar to particles found in other Stardust studies. Collectively, the evidence points to gas acquisition in a hot, high ion-flux nebular environment close to the young Sun.

  13. Water depth measurement using an airborne pulsed neon laser system

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.; Frederick, E. B.

    1980-01-01

    The paper presents the water depth measurement using an airborne pulsed neon laser system. The results of initial base-line field test results of NASA airborne oceanographic lidar in the bathymetry mode are given, with water-truth measurements of depth and beam attenuation coefficients by boat taken at the same time as overflights to aid in determining the system's operational performance. The nadir-angle tests and field-of-view data are presented; this laser bathymetry system is an improvement over prior models in that (1) the surface-to-bottom pulse waveform is digitally recorded on magnetic tape, and (2) wide-swath mapping data may be routinely acquired using a 30 deg full-angle conical scanner.

  14. Endogenous circadian retinomotor movements in the neon tetra (Paracheirodon innesi).

    PubMed

    Lythgoe, J N; Shand, J

    1983-09-01

    Retinomotor movements of retinal cones and pigment epithelium melanosomes were studied in the neon tetra, Paracheirodon innesi. The cone myoids clearly contracted during the daytime, but the migration of the total population of pigment granules was less easy to see. However, when rod-shaped melanosomes were measured separately from granular-shaped melanosomes it became evident that the rod-shaped melanosomes, but not the granular melanosomes, did migrate in response to circadian changes in light intensity. Retinomotor movements of both the cones and the rod-shaped melanosomes persisted for at least 2 days in continuous darkness. Microspectrophotometric measurements of spectral transmission of small groups of melanosomes showed that absorption was greatest at shorter wavelengths, but that there was also a distinct absorbance maximum at about 480 nm.

  15. Experimental evidence of the Frenkel line in supercritical neon

    NASA Astrophysics Data System (ADS)

    Prescher, C.; Fomin, Yu. D.; Prakapenka, V. B.; Stefanski, J.; Trachenko, K.; Brazhkin, V. V.

    2017-04-01

    Recent research suggests that the supercritical state consists of liquidlike and gaslike states where particle dynamics and key system properties are qualitatively different. We report experimental evidence of the structural crossover in supercritical neon at pressure and temperature conditions significantly exceeding the critical point values: 250 Pc and 6.6 Tc . The experimental results show a crossover of the medium-range order structure evidenced by the change of the structure factor with pressure. We also observe the crossover of the short-range order structure indicated by changes in the coordination number. The relative width of the crossover is fairly narrow and is smaller than 10-12% in pressure and temperature. By comparing our experimental results with molecular dynamics simulations, we suggest that the observed crossover can be attributed to the Frenkel line and discuss the relationship between the structural crossover and qualitative changes of dynamical and thermodynamic properties of supercritical matter.

  16. Attainable superheat of argon-helium, argon-neon solutions.

    PubMed

    Baidakov, Vladimir G; Kaverin, Aleksey M; Andbaeva, Valentina N

    2008-10-16

    The method of lifetime measurement has been used to investigate the kinetics of spontaneous boiling-up of superheated argon-helium and argon-neon solutions. Experiments were made at a pressure of p = 1.5 MPa and concentrations up to 0.33 mol% in the range of nucleation rates from 10 (4) to 10 (8) s (-1) m (-3). The homogeneous nucleation regime has been distinguished. With good agreement between experimental data and homogeneous nucleation theory in temperature and concentration dependences of the nucleation rate, a systematic underestimation by 0.25-0.34 K has been revealed in superheat temperatures over the saturated line attained by experiment as compared with theoretical values calculated in a macroscopic approximation. The revealed disagreement between theory and experiment is connected with the dependence of the properties of new-phase nuclei on their size.

  17. Helium and Neon Abundances and Compositions in Cometary Matter

    SciTech Connect

    Marty, B; Palma, R L; Pepin, R O; Zimmmermann, L; Schlutter, D J; Burnard, P G; Westphal, A J; Snead, C J; Bajt, S; Becker, R H; Simones, J E

    2007-10-15

    Materials trapped and preserved in comets date from the earliest history of the solar system. Particles captured by the Stardust spacecraft from comet Wild 2 are indisputable cometary matter available for laboratory study. Here they report measurements of noble gases in Stardust material. neon isotope ratios are within the range observed in 'phase Q', a ubiquitous, primitive organic carrier of noble gases in meteorites. Helium displays {sup 3}He/{sup 4}He ratios twice those in phase Q and in Jupiter's atmosphere. Abundances per gram are surprisingly large, suggesting implantation by ion irradiation. The gases are carried in high temperature igneous grains similar to particles found in other Stardust studies. Collectively the evidence points to gas acquisition in a hot, high ion flux nebular environment close to the young Sun.

  18. Equation of state of dense neon and krypton plasmas in the partial ionization regime

    SciTech Connect

    Chen, Q. F. Zheng, J.; Gu, Y. J.; Li, Z. G.

    2015-12-15

    The compression behaviors of dense neon and krypton plasmas over a wide pressure-temperature range are investigated by self-consistent fluid variational theory. The ionization degree and equation of state of dense neon and krypton are calculated in the density-temperature range of 0.01–10 g/cm{sup 3} and 4–50 kK. A region of thermodynamic instability is found which is related to the plasma phase transition. The calculated shock adiabat and principal Hugoniot of liquid krypton are in good agreement with available experimental data. The predicted results of shock-compressed liquid neon are presented, which provide a guide for dynamical experiments or numerical first-principle calculations aimed at studying the compression properties of liquid neon in the partial ionization regime.

  19. Neon isotopes constrain convection and volatile origin in the Earth's mantle.

    PubMed

    Ballentine, Chris J; Marty, Bernard; Sherwood Lollar, Barbara; Cassidy, Martin

    2005-01-06

    Identifying the origin of primordial volatiles in the Earth's mantle provides a critical test between models that advocate magma-ocean equilibration with an early massive solar-nebula atmosphere and those that require subduction of volatiles implanted in late accreting material. Here we show that neon isotopes in the convecting mantle, resolved in magmatic CO2 well gases, are consistent with a volatile source related to solar corpuscular irradiation of accreting material. This contrasts with recent results that indicated a solar-nebula origin for neon in mantle plume material, which is thought to be sampling the deep mantle. Neon isotope heterogeneity in different mantle sources suggests that models in which the plume source supplies the convecting mantle with its volatile inventory require revision. Although higher than accepted noble gas concentrations in the convecting mantle may reduce the need for a deep mantle volatile flux, any such flux must be dominated by the neon (and helium) isotopic signature of late accreting material.

  20. Neon as a Buffer Gas for a Mercury-Ion Clock

    NASA Technical Reports Server (NTRS)

    Prestage, John; Chung, Sang

    2008-01-01

    A developmental miniature mercury-ion clock has stability comparable to that of a hydrogen-maser clock. The ion-handling components are housed in a sealed vacuum tube, wherein a getter pump is used to maintain the partial vacuum, and the evacuated tube is backfilled with mercury vapor in a buffer gas. Neon was determined to be the best choice for the buffer gas: The pressure-induced frequency pulling by neon was found to be only about two-fifths of that of helium. Furthermore, because neon diffuses through solids much more slowly than does helium, the operational lifetime of a tube backfilled with neon could be considerably longer than that of a tube backfilled with helium.

  1. Fragmentation dynamics of ionized neon trimer inside helium nanodroplets: a theoretical study.

    PubMed

    Bonhommeau, David; Viel, Alexandra; Halberstadt, Nadine

    2004-06-22

    We report a theoretical study of the fragmentation dynamics of Ne(3) (+) inside helium nanodroplets, following vertical ionization of the neutral neon trimer. The motion of the neon atoms is treated classically, while transitions between the electronic states of the ionic cluster are treated quantum mechanically. A diatomics-in-molecules description of the potential energy surfaces is used, in a minimal basis set consisting of three effective p orbitals on each neon atom for the missing electron. The helium environment is modeled by a friction force acting on the neon atoms when their speed exceeds the Landau velocity. A reasonable range of values for the corresponding friction coefficient is obtained by comparison with existing experimental measurements.

  2. Quantum dynamical structure factor of liquid neon via a quasiclassical symmetrized method

    NASA Astrophysics Data System (ADS)

    Monteferrante, Michele; Bonella, Sara; Ciccotti, Giovanni

    2013-02-01

    We apply the phase integration method for quasiclassical quantum time correlation functions [M. Monteferrante, S. Bonella, and G. Ciccotti, Mol. Phys. 109, 3015 (2011), 10.1080/00268976.2011.619506] to compute the dynamic structure factor of liquid neon. So far the method had been tested only on model systems. By comparing our results for neon with experiments and previous calculations, we demonstrate that the scheme is accurate and efficient also for a realistic model of a condensed phase system showing quantum behavior.

  3. Laser optogalvanic wavelength calibration with a commercial hollow cathode iron - neon discharge lamp

    NASA Technical Reports Server (NTRS)

    Zhu, Xinming; Nur, Abdullahi H.; Misra, Prabhakar

    1994-01-01

    351 optogalvanic transitions have been observed in the 337 - 598 nm wavelength region using an iron - neon hollow cathode discharge lamp and a pulsed tunable dye laser. 223 of these have been identified as transitions associated with neon energy levels. These optogalvanic transitions have allowed, in conjunction with interference fringes recorded concomitantly with an etalon, the calibration of the dye laser wavelength with 0.3/cm accuracy.

  4. Method and apparatus for cooling high temperature superconductors with neon-nitrogen mixtures

    DOEpatents

    Laverman, Royce J.; Lai, Ban-Yen

    1993-01-01

    Apparatus and methods for cooling high temperature superconducting materials (HTSC) to superconductive temperatures within the range of 27.degree. K. to 77.degree. K. using a mixed refrigerant consisting of liquefied neon and nitrogen containing up to about ten mole percent neon by contacting and surrounding the HTSC material with the mixed refrigerant so that free convection or forced flow convection heat transfer can be effected.

  5. Laser optogalvanic wavelength calibration with a commercial hollow cathode iron - neon discharge lamp

    NASA Technical Reports Server (NTRS)

    Zhu, Xinming; Nur, Abdullahi H.; Misra, Prabhakar

    1994-01-01

    351 optogalvanic transitions have been observed in the 337 - 598 nm wavelength region using an iron - neon hollow cathode discharge lamp and a pulsed tunable dye laser. 223 of these have been identified as transitions associated with neon energy levels. These optogalvanic transitions have allowed, in conjunction with interference fringes recorded concomitantly with an etalon, the calibration of the dye laser wavelength with 0.3/cm accuracy.

  6. Emission anomalous optical magnetic resonances in a mixture of even neon isotopes

    SciTech Connect

    Saprykin, E. G.; Sorokin, V. A. Shalagin, A. M.

    2013-04-15

    Unusual resonances have been detected in the dependence of the discharge glow in neon on the longitudinal magnetic field. The resonances appear in fairly high magnetic fields and are observed only at low gas pressures and exclusively in a mixture of {sup 20}Ne and {sup 22}Ne isotopes. This phenomenon is an evidence of collective resonant radiation processes involving atoms of different neon isotopes.

  7. A comparison of neon versus helium ion beam induced deposition via Monte Carlo simulations.

    PubMed

    Timilsina, Rajendra; Smith, Daryl A; Rack, Philip D

    2013-03-22

    The ion beam induced nanoscale synthesis of PtCx (where x ∼ 5) using the trimethyl (methylcyclopentadienyl)platinum(IV) (MeCpPt(IV)Me3) precursor is investigated by performing Monte Carlo simulations of helium and neon ions. The helium beam leads to more lateral growth relative to the neon beam because of its larger interaction volume. The lateral growth of the nanopillars is dominated by molecules deposited via secondary electrons in both the simulations. Notably, the helium pillars are dominated by SE-I electrons whereas the neon pillars are dominated by SE-II electrons. Using a low precursor residence time of 70 μs, resulting in an equilibrium coverage of ∼4%, the neon simulation has a lower deposition efficiency (3.5%) compared to that of the helium simulation (6.5%). At larger residence time (10 ms) and consequently larger equilibrium coverage (85%) the deposition efficiencies of helium and neon increased to 49% and 21%, respectively; which is dominated by increased lateral growth rates leading to broader pillars. The nanoscale growth is further studied by varying the ion beam diameter at 10 ms precursor residence time. The study shows that total SE yield decreases with increasing beam diameters for both the ion types. However, helium has the larger SE yield as compared to that of neon in both the low and high precursor residence time, and thus pillars are wider in all the simulations studied.

  8. Electrical Properties for Capacitively Coupled Radio Frequency Discharges of Helium and Neon at Low Pressure

    NASA Astrophysics Data System (ADS)

    Tanisli, Murat; Sahin, Neslihan; Demir, Suleyman

    2016-10-01

    In this study, the symmetric radio frequency (RF) electrode discharge is formed between the two electrodes placing symmetric parallel. The electrical properties of symmetric capacitive RF discharge of pure neon and pure helium have been obtained from current and voltage waveforms. Calculations are done according to the homogeneous discharge model of capacitively coupled radio frequency (CCRF) using with the data in detail. Electrical properties of bulk plasma and sheath capacitance are also investigated at low pressure with this model. This study compares the electrical characteristics and sheath capacitance changes with RF power and pressure for helium and neon discharges. Also, the aim of the study is to see the differences between helium and neon discharges' current and voltage values. Their root-mean-square voltages and currents are obtained from Tektronix 3052C oscilloscope. Modified homogeneous discharge model of CCRF is used for low pressure discharges and the calculations are done using experimental results. It is seen that homogeneous discharge model of CCRF is usable with modification and then helium and neon discharge's electrical properties are investigated and presented with a comparison. Helium discharge's voltage and current characteristic have smaller values than neon's. It may be said that neon discharge is a better conductor than helium discharge. It is seen that the sheath capacitance is inversely correlation with sheath resistance.

  9. Temperature-dependent anisotropic resistivity in electron, hole and isoelectron - doped BaFe2As2 superconductors

    NASA Astrophysics Data System (ADS)

    Tanatar, M. A.

    2012-02-01

    Anisotropic electrical resistivity, ρ(T), was studied in iron-arsenide superconductors, obtained by doping the parent BaFe2As2 compound on three different sites: (1) electron donor transition metal (Co,Ni,Rh,Pd) substitution of Fe [1,2]; (2) hole donor K substitution of Ba [3]; (3) isoelectron P substitution of As. For all three types of dopants a range of T-linear behavior is found at the optimal doping in both the in-plane and the inter-plane ρ(T) above Tc. At some higher temperature this range of T-linear resistivity is capped by a slope-changing anomaly, which, by comparison with NMR, magnetic susceptibility and Hall effect measurements, can be identified with the onset of carrier activation over the pseudogap [1]. The doping-evolution of anisotropic temperature dependent ρ(T) and of the pseudogap are quite different for three types of doping. A three-dimensional T-H phase diagram summarizing our results will be presented. Furthermore, potential correlation of the anisotropic normal state transport and anisotropic superconducting state heat transport will be discussed. [4pt] In collaboration with N. Ni, A. Thaler, S.L.Bud'ko, P.C. Canfield, R. Prozorov, Bing Shen, Hai-Hu Wen, K. Hashimoto, S. Kasahara, T. Terashima, T. Shibauchi and Y. Matsuda. [4pt] [1] M.A.Tanatar et al. PRB 82, 134528 (2010)[0pt] [2] M.A.Tanatar et al. PRB 84, 014519 (2011)[0pt] [3] M.A.Tanatar et al. arXiv:1106.0533

  10. Stereo-Selectivity of Human Serum Albumin to Enantiomeric and Isoelectronic Pollutants Dissected by Spectroscopy, Calorimetry and Bioinformatics

    PubMed Central

    Ahmad, Ejaz; Rabbani, Gulam; Zaidi, Nida; Singh, Saurabh; Rehan, Mohd; Khan, Mohd Moin; Rahman, Shah Kamranur; Quadri, Zainuddin; Shadab, Mohd.; Ashraf, Mohd Tashfeen; Subbarao, Naidu; Bhat, Rajiv; Khan, Rizwan Hasan

    2011-01-01

    1–naphthol (1N), 2–naphthol (2N) and 8–quinolinol (8H) are general water pollutants. 1N and 2N are the configurational enantiomers and 8H is isoelectronic to 1N and 2N. These pollutants when ingested are transported in the blood by proteins like human serum albumin (HSA). Binding of these pollutants to HSA has been explored to elucidate the specific selectivity of molecular recognition by this multiligand binding protein. The association constants (Kb) of these pollutants to HSA were moderate (104–105 M−1). The proximity of the ligands to HSA is also revealed by their average binding distance, r, which is estimated to be in the range of 4.39–5.37 nm. The binding free energy (ΔG) in each case remains effectively the same for each site because of enthalpy–entropy compensation (EEC). The difference observed between ΔCpexp and ΔCpcalc are suggested to be caused by binding–induced flexibility changes in the HSA. Efforts are also made to elaborate the differences observed in binding isotherms obtained through multiple approaches of calorimetry, spectroscopy and bioinformatics. We suggest that difference in dissociation constants of pollutants by calorimetry, spectroscopic and computational approaches could correspond to occurrence of different set of populations of pollutants having different molecular characteristics in ground state and excited state. Furthermore, our observation of enhanced binding of pollutants (2N and 8H) in the presence of hemin signifies that ligands like hemin may enhance the storage period of these pollutants in blood that may even facilitate the ill effects of these pollutants. PMID:22073150

  11. Helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure: A superior option.

    PubMed

    Xu, Qi-Hua; Zhao, Chen; Zhu, Jian-Gang; Chen, Mei-Juan; Liu, Qing-Huai

    2015-09-01

    The aim of the present study was to evaluate the efficacy of helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure and compare the results with those of a combined drugs and surgery regimen. A total of 70 patients with hydroxyapatite orbital implant exposure in 70 eyes were randomly divided into two groups: Helium-neon laser therapy (group A) and drugs plus surgery (group B). Each group contained 35 patients. The healing rates and times of the conjunctival wound were recorded and compared following helium-neon laser treatment or the drugs plus surgery regimen. Changes in the hydroxyapatite orbital implant prior to and following helium-neon laser irradiation were analyzed. A similar animal study was conducted using 24 New Zealand white rabbits, which received orbital implants and were then received drug treatment or helium-neon therapy. In the human experiment, the rates for conjunctival wound healing were 97.14% in group A and 74.29% in group B, with a significant difference between the groups (χ(2)=5.71, P<0.05). Patients with mild exposure were healed after 7.22±2.11 days of helium-neon laser therapy and 14.33±3.20 days of drugs plus surgery. A statistically significant difference was found between the groups (t=8.97, P<0.05). Patients with moderate to severe exposure were healed after 18.19±2.12 days of helium-neon laser therapy and 31.25±4.21 days of drugs plus surgery. The difference between the groups was statistically significant (t=7.91, P<0.05). Enhanced magnetic resonance imaging showed that the helium-neon laser therapy significantly promoted vascularization of the hydroxyapatite orbital implant. These results, combined with pathological findings in animals, which showed that a helium-neon laser promoted vascularization and had anti-inflammatory effects, suggest that helium-neon laser irradiation is an effective method for treating hydroxyapatite orbital implant exposure, thereby avoiding secondary surgery.

  12. Helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure: A superior option

    PubMed Central

    XU, QI-HUA; ZHAO, CHEN; ZHU, JIAN-GANG; CHEN, MEI-JUAN; LIU, QING-HUAI

    2015-01-01

    The aim of the present study was to evaluate the efficacy of helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure and compare the results with those of a combined drugs and surgery regimen. A total of 70 patients with hydroxyapatite orbital implant exposure in 70 eyes were randomly divided into two groups: Helium-neon laser therapy (group A) and drugs plus surgery (group B). Each group contained 35 patients. The healing rates and times of the conjunctival wound were recorded and compared following helium-neon laser treatment or the drugs plus surgery regimen. Changes in the hydroxyapatite orbital implant prior to and following helium-neon laser irradiation were analyzed. A similar animal study was conducted using 24 New Zealand white rabbits, which received orbital implants and were then received drug treatment or helium-neon therapy. In the human experiment, the rates for conjunctival wound healing were 97.14% in group A and 74.29% in group B, with a significant difference between the groups (χ2=5.71, P<0.05). Patients with mild exposure were healed after 7.22±2.11 days of helium-neon laser therapy and 14.33±3.20 days of drugs plus surgery. A statistically significant difference was found between the groups (t=8.97, P<0.05). Patients with moderate to severe exposure were healed after 18.19±2.12 days of helium-neon laser therapy and 31.25±4.21 days of drugs plus surgery. The difference between the groups was statistically significant (t=7.91, P<0.05). Enhanced magnetic resonance imaging showed that the helium-neon laser therapy significantly promoted vascularization of the hydroxyapatite orbital implant. These results, combined with pathological findings in animals, which showed that a helium-neon laser promoted vascularization and had anti-inflammatory effects, suggest that helium-neon laser irradiation is an effective method for treating hydroxyapatite orbital implant exposure, thereby avoiding secondary surgery. PMID

  13. Effect of charge transfer on the local order in liquid group IV isoelectronic compounds: neutron diffraction data versus numerical tight-binding simulations

    SciTech Connect

    Prigent, G.; Bellissent, R.; Gaspard, J.-P.; Bichara, C.

    1999-06-15

    In a simple tight-binding approach, we consider the role of charge transfer and entropy in the semiconductor-to-metal transition which may occur upon melting group IV elements and their isoelectronic III-V and II-VI compounds. In the liquid state, entropy is shown to destabilise the diamond structure in favor of a metallic simple cubic-like local order, while charge transfer tends to keep the semiconducting tetrahedral local order of the solid state. These results are consistent with neutron diffraction data.

  14. One- and two-body densities of carbon isoelectronic series in their low-lying multiplet states from explicitly correlated wave functions.

    PubMed

    Gálvez, F J; Buendía, E; Sarsa, A

    2006-01-28

    The (3)P ground state and both the (1)D and (1)S excited states arising from the low-lying 1s(2)2s(2)2p(2) configuration of the carbon isoelectronic series are studied starting from explicitly correlated multiconfigurational wave functions. One- and two-body densities in position space have been calculated and different one- and two-body expectation values have been obtained. The effects of electronic correlations have been systematically studied. All the calculations have been done by means of variational Monte Carlo.

  15. Big Data and Big Models: Using NEON Data to Inform the Community Land Model

    NASA Astrophysics Data System (ADS)

    Fox, A. M.; Hoar, T. J.

    2015-12-01

    A grand challenge in environmental science is predicting the future trajectory of the terrestrial carbon cycle as simulated in coupled Earth System Models. However, simulations remain highly uncertain despite ever increasing availability of observations. Therefore, finding new ways to use data to evaluate, benchmark and constrain models, and improve forecasts through data assimilation, is critical to making progress in reducing these uncertainties. One of the largest sources of "big data" for use in biogeosciences is becoming available from the NSF-funded National Ecological Observatory Network (NEON). This represents enormous potential for enhancing carbon cycle modeling, but also a new challenge in how such large amounts of information can be utilized most effectively. NEON data will be streaming from approximately 15,000 sensors, of roughly 200 distinct types with measurement frequencies up to 40 hertz. Observations will be made at 2000 plots at over 60 sites, and NEON will acquire airborne hyperspectral and LiDAR data over 5500 km2 at sub 1-meter resolution annually. In all, NEON will be producing about a petabyte of data per year. In this presentation we first provide a update on the status of NEON. Second, we illustrate how many NEON observations correspond with key pools and fluxes of carbon and water in land surface models at a variety of spatial and temporal scales. We then highlight some of the challenges associated with using site level data such as these with gridded, global land surface models due to mismatches in scales, and how these might be addressed. Finally, we demonstrate how infrastructure we have developed coupling the Community Land Model and the Data Assimilation Testbed allows us to assimilate NEON-type data, and conduct an observing system simulation experiment that investigated the impact of network design on modeled carbon pools and fluxes across North America.

  16. Primordial atmosphere incorporation in planetary embryos and the origin of Neon in terrestrial planets

    NASA Astrophysics Data System (ADS)

    Jaupart, Etienne; Charnoz, Sebatien; Moreira, Manuel

    2017-09-01

    The presence of Neon in terrestrial planet mantles may be attributed to the implantation of solar wind in planetary precursors or to the dissolution of primordial solar gases captured from the accretionary disk into an early magma ocean. This is suggested by the Neon isotopic ratio similar to those of the Sun observed in the Earth mantle. Here, we evaluate the second hypothesis. We use general considerations of planetary accretion and atmospheric science. Using current models of terrestrial planet formation, we study the evolution of standard planetary embryos with masses in a range of 0.1-0.2 MEarth, where MEarth is the Earth's mass, in an annular region at distances between 0.5 and 1.5 Astronomical Units from the star. We determine the characteristics of atmospheres that can be captured by such embryos for a wide range of parameters and calculate the maximum amount of Neon that can be dissolved in the planet. Our calculations may be directly transposed to any other planet. However, we only know of the amount of Neon in the Earth's solid mantle. Thus we use Earth to discuss our results. We find that the amount of dissolved Neon is too small to account for the present-day Neon contents of the Earth's mantle, if the nebular gas disk completely disappears before the largest planetary embryos grow to be ∼0.2 MEarth. This leaves solar irradiation as the most likely source of Neon in terrestrial planets for the most standard case of planetary formation models.

  17. Interstellar oxygen, nitrogen and neon in the heliosphere

    NASA Technical Reports Server (NTRS)

    Geiss, J.; Gloeckler, G.; Mall, U.; Von Steiger, R.; Galvin, A. B.; Ogilvie, K. W.

    1994-01-01

    Oxygen, nitrogen and neon pick-up ions of interstellar origin were detected for the first time with the Solar Wind Ion Spectrometer (SWICS) on board Ulysses. The interstellar origin of these ions is established by the following criteria: (a) they are singly charged, (b) they have the broad velocity distributions characteristic of pick-up ions, with an upper limit of twice the solar wind speed, (c) their relative abundance as a function of distance from the sun corresponds to the theoretical expectation, and (d) there is no relation to a planetary or cometary source. The interstellar abundance ratios He(+)/O(+), N(+)/O(+), Ne(+)/O(+) were investigated. At approximately 5.25 AU in the outermost part of Ulysses' trajectory He(+)/O(+) = 175(sup +70 sub -50) N(+)/O(+) = 0.13(sup +0.05 sub -0.05) and Ne(+)/O(+) = 0.18(sup +0.10 sub -0.07) were determined. For the interstellar gas passing through the termination region and entering the heliosphere (He/O)(sub 0) = 290(sup +190 sub -100), (N/O)(sub 0) = 0.13(sup +0.06 sub -0.06) and (Ne/O)(sub 0) = 0.20(sup +0.12 sub -0.09) were obtained from the pick-up ion measurements. Upper limits for the relative abundances of C(+) and C were also determined.

  18. Helium and neon in lunar ilmenites of different antiquities

    NASA Technical Reports Server (NTRS)

    Nier, A. O.; Schlutter, D. J.

    1994-01-01

    Helium and neon were extracted from individual lunar ilmenite grains, approximately 100 micrometers in diameter, using a pulsed step-heating technique. Grains from lunar samples 71501 and 79035, believed to have been exposed to solar corpuscular radiation at greatly different times, were studied. The results found were consistent with the hypothesis that in addition to solar-wind-implanted gas, a second more deeply implanted component was present in both species of grains. Average isotopic ratios were determined giving equal weight to each of the particles. As found in depth studies employing chemical etching, both the He-3/He-4 and Ne-20/Ne-22 ratios were lower in the more deeply implanted gas than in the solar wind component. The He-3/He-4 ratio in the solar wind component of the more ancient grains was lower than that in the more recently exposed ones, whereas no difference was found for the more deeply embedded He. In the deeply embedded component of the ancient grains, the He-4/Ne-20 ratio was approx. 2x that found in the more recently exposed grains. In the shallowly implanted component, the ratio varied greatly from grain to grain, preventing comparison with the solar wind elemental composition.

  19. Isotopes of cosmic ray elements from neon to nickel

    NASA Technical Reports Server (NTRS)

    Waddington, C. J.; Freier, P. S.; Fickle, R. K.; Brewster, N. R.

    1981-01-01

    Results obtained from a balloon exposure of a cosmic ray detector flown in 1977 are reported. The charge resolution ranged from 0.19 to 0.21 charge units between neon and nickel and the mass resolution for nuclei stopped in the emulsions ranged from 0.40 to 0.70 amu for A between 20 and 60 amu. This was enough to correctly identify almost all nuclei, but not to uniquely resolve neighboring mass peaks. Both Ne and Mg show evidence for neutron enrichment relative to the solar system abundance. Si and S are consistent with solar abundances, while Ar has no significant source abundances. P, Cl and K have essentially no primary component and the isotopic distribution observed is quite consistent with that expected from propagation. An excess of Ca-44 at the source is shown, indicating high metallicity in the source. The abundance of Fe-58 is nine percent or less, and Ni shows a one-to-one ratio for Ni-58 to 60, implying intermediate metallicity.

  20. The isotopes of neon in the galactic cosmic rays

    NASA Technical Reports Server (NTRS)

    Garcia-Munoz, M.; Simpson, J. A.; Wefel, J. P.

    1979-01-01

    The paper examines the results obtained by the University of Chicago instrument on board the IMP 7 satellite used to measure the abundances of Ne-20 and Ne-22 in the galactic cosmic rays during 1973-1977, over the general energy range of 60-230 MeV per nucleon. It is reported that the instrument shows a mass resolution of 0.7 amu(sigma) which was confirmed by calibrating a backup instrument at the LBL Bevalac with separated beams of neon isotopes. Through the use of standard solar modulation and cosmic-ray propagation models, the cosmic-ray source ratio inferred is Ne-22/Ne-20 = 0.38 = or -0.07 which is significantly greater than the present solar system ratio. It is concluded that propagation effects or cross-section uncertainties cannot account for such a large abundance of Ne-22, and thus this measurement provides evidence that the cosmic rays come from a source region where the Ne-22 abundance is substantially greater than in solar system material.

  1. Helium and neon in lunar ilmenites of different antiquities

    NASA Technical Reports Server (NTRS)

    Nier, A. O.; Schlutter, D. J.

    1994-01-01

    Helium and neon were extracted from individual lunar ilmenite grains, approximately 100 micrometers in diameter, using a pulsed step-heating technique. Grains from lunar samples 71501 and 79035, believed to have been exposed to solar corpuscular radiation at greatly different times, were studied. The results found were consistent with the hypothesis that in addition to solar-wind-implanted gas, a second more deeply implanted component was present in both species of grains. Average isotopic ratios were determined giving equal weight to each of the particles. As found in depth studies employing chemical etching, both the He-3/He-4 and Ne-20/Ne-22 ratios were lower in the more deeply implanted gas than in the solar wind component. The He-3/He-4 ratio in the solar wind component of the more ancient grains was lower than that in the more recently exposed ones, whereas no difference was found for the more deeply embedded He. In the deeply embedded component of the ancient grains, the He-4/Ne-20 ratio was approx. 2x that found in the more recently exposed grains. In the shallowly implanted component, the ratio varied greatly from grain to grain, preventing comparison with the solar wind elemental composition.

  2. The thermal conductivity of neon, methane and tetrafluoromethane

    NASA Astrophysics Data System (ADS)

    Millat, J.; Ross, M.; Wakeham, W. A.; Zalaf, M.

    1988-02-01

    New, absolute measurements of the thermal conductivity of neon (Ne), methane (CH 4) and tetrafluoromethane (CF 4) are reported for the temperature range 308 to 428 K at pressures up to 10 MPa. The data have an estimated accuracy of ±0.3%. A statistical analysis of the density dependence of the thermal conductivity has been employed to deduce the thermal conductivity of the gases in the limit of zero density and the firt density coefficient. For methane the first density coefficient is well represented by a correlation based on data for monatomic gases whereas for tetrafluoromethane the same correlation greatly underestimates the same coefficient. The thermal conductivity in the limit of zero density has been used in conjuction with other transport property data to deduce a consistent set of effective cross-sections for the two gases over all the range of temperature studied, based entirely on experiment. Among other quantities the collision number for rotational relaxation has been deduced and is shown to be significantly different between the two gases. Although the Mason-Monchick approximation is inappropriate for the evaluation of some of the effective cross-sections for the gases, a recent, very simple formulation of the kinetic theory of polyatomic gases provides a satisfactory description of the thermal conductivity data.

  3. Interstellar oxygen, nitrogen and neon in the heliosphere

    NASA Technical Reports Server (NTRS)

    Geiss, J.; Gloeckler, G.; Mall, U.; Von Steiger, R.; Galvin, A. B.; Ogilvie, K. W.

    1994-01-01

    Oxygen, nitrogen and neon pick-up ions of interstellar origin were detected for the first time with the Solar Wind Ion Spectrometer (SWICS) on board Ulysses. The interstellar origin of these ions is established by the following criteria: (a) they are singly charged, (b) they have the broad velocity distributions characteristic of pick-up ions, with an upper limit of twice the solar wind speed, (c) their relative abundance as a function of distance from the sun corresponds to the theoretical expectation, and (d) there is no relation to a planetary or cometary source. The interstellar abundance ratios He(+)/O(+), N(+)/O(+), Ne(+)/O(+) were investigated. At approximately 5.25 AU in the outermost part of Ulysses' trajectory He(+)/O(+) = 175(sup +70 sub -50) N(+)/O(+) = 0.13(sup +0.05 sub -0.05) and Ne(+)/O(+) = 0.18(sup +0.10 sub -0.07) were determined. For the interstellar gas passing through the termination region and entering the heliosphere (He/O)(sub 0) = 290(sup +190 sub -100), (N/O)(sub 0) = 0.13(sup +0.06 sub -0.06) and (Ne/O)(sub 0) = 0.20(sup +0.12 sub -0.09) were obtained from the pick-up ion measurements. Upper limits for the relative abundances of C(+) and C were also determined.

  4. Effect of helium-neon laser on musculoskeletal trigger points

    SciTech Connect

    Snyder-Mackler, L.; Bork, C.; Bourbon, B.; Trumbore, D.

    1986-07-01

    Cold lasers have been proposed recently as a therapeutic tool for treating a wide variety of pathological conditions, including wounds, arthritis, orthopedic problems, and pain. These proposed therapeutic effects largely have been unsubstantiated by research. A randomized, double blind study was undertaken to ascertain the effect of a helium-neon (He-Ne) laser on the resistance of areas of skin overlying musculoskeletal trigger points. These areas usually demonstrate decreased skin resistance when compared with the surrounding tissue. Thirty patients with musculoskeletal trigger points were assigned randomly to either an experimental or a placebo group. In addition to standard physical therapy, each patient received three 15-second applications of a He-Ne laser or placebo stimulation from an identical unit that did not emit a laser. The results of a two-way analysis of covariance with one repeated measure showed a statistically significant increase (p less than .007) in skin resistance. This increase in an abnormal skin resistance pattern may accompany the resolution of pathological conditions.

  5. Neon turbo-Brayton cycle refrigerator for HTS power machines

    NASA Astrophysics Data System (ADS)

    Hirai, Hirokazu; Hirokawa, M.; Yoshida, Shigeru; Nara, N.; Ozaki, S.; Hayashi, H.; Okamoto, H.; Shiohara, Y.

    2012-06-01

    We developed a prototype turbo-Brayton refrigerator whose working fluid is neon gas. The refrigerator is designed for a HTS (High Temperature Superconducting) power transformer and its cooling power is more than 2 kW at 65 K. The refrigerator has a turboexpander and a turbo-compressor, which utilize magnetic bearings. These rotational machines have no rubbing parts and no oil-components. Those make a long maintenance interval of the refrigerator. The refrigerator is very compact because our newly developed turbo-compressor is volumetrically smaller than a displacement type compressor in same operating specification. Another feature of the refrigerator is a wide range operation capability for various heat-loads. Cooling power is controlled by the input-power of the turbo-compressor instead of the conventional method of using an electric heater. The rotational speed of the compressor motor is adjusted by an inverter. This system is expected to be more efficient. We show design details, specification and cooling test results of the new refrigerator in this paper.

  6. Observation of the weak electronic correlations in KFeCoAs2 (3d 6): an isoelectronic to the parent compounds of 122 series of iron pnictides BaFe2As2

    NASA Astrophysics Data System (ADS)

    Liu, Z. H.; Yaresko, A. N.; Li, Y.; Dai, P. C.; Zhang, H.; Büchner, B.; Lin, C. T.; Borisenko, S. V.

    2017-03-01

    Using the angle-resolved photoemission spectroscopy and band structure calculations we study the electronic structure of KFeCoAs2, which is isoelectronic to the parent material of 122 series of iron-based superconductors BaFe2As2. Although band structure calculations predict nearly identical dispersions of the electronic states in both compounds, experiment reveals drastic differences in both the global renormalization and Fermi surfaces. On the basis of the comparison of electronic structures of these two isoelectronic compounds, we demonstrate local magnetic correlations as a vital role for the peculiar low-energy electron dynamics of iron-based superconductors.

  7. A strategy to sample nutrient dynamics across the terrestrial-aquatic interface at NEON sites

    NASA Astrophysics Data System (ADS)

    Hinckley, E. S.; Goodman, K. J.; Roehm, C. L.; Meier, C. L.; Luo, H.; Ayres, E.; Parnell, J.; Krause, K.; Fox, A. M.; SanClements, M.; Fitzgerald, M.; Barnett, D.; Loescher, H. W.; Schimel, D.

    2012-12-01

    The construction of the National Ecological Observatory Network (NEON) across the U.S. creates the opportunity for researchers to investigate biogeochemical transformations and transfers across ecosystems at local-to-continental scales. Here, we examine a subset of NEON sites where atmospheric, terrestrial, and aquatic observations will be collected for 30 years. These sites are located across a range of hydrological regimes, including flashy rain-driven, shallow sub-surface (perched, pipe-flow, etc), and deep groundwater, which likely affect the chemical forms and quantities of reactive elements that are retained and/or mobilized across landscapes. We present a novel spatial and temporal sampling design that enables researchers to evaluate long-term trends in carbon, nitrogen, and phosphorus biogeochemical cycles under these different hydrological regimes. This design focuses on inputs to the terrestrial system (atmospheric deposition, bulk precipitation), transfers (soil-water and groundwater sources/chemistry), and outputs (surface water, and evapotranspiration). We discuss both data that will be collected as part of the current NEON design, as well as how the research community can supplement the NEON design through collaborative efforts, such as providing additional datasets, including soil biogeochemical processes and trace gas emissions, and developing collaborative research networks. Current engagement with the research community working at the terrestrial-aquatic interface is critical to NEON's success as we begin construction, to ensure that high-quality, standardized and useful data are not only made available, but inspire further, cutting-edge research.

  8. Neon-Bearing Ammonium Metal Formates: Formation and Behaviour under Pressure.

    PubMed

    Collings, Ines E; Bykova, Elena; Bykov, Maxim; Petitgirard, Sylvain; Hanfland, Michael; Paliwoda, Damian; Dubrovinsky, Leonid; Dubrovinskaia, Natalia

    2016-11-04

    The incorporation of noble gas atoms, in particular neon, into the pores of network structures is very challenging due to the weak interactions they experience with the network solid. Using high-pressure single-crystal X-ray diffraction, we demonstrate that neon atoms enter into the extended network of ammonium metal formates, thus forming compounds Nex [NH4 ][M(HCOO)3 ]. This phenomenon modifies the compressional and structural behaviours of the ammonium metal formates under pressure. The neon atoms can be clearly localised within the centre of [M(HCOO)3 ]5 cages and the total saturation of this site is achieved after ∼1.5 GPa. We find that by using argon as the pressure-transmitting medium, the inclusion inside [NH4 ][M(HCOO)3 ] is inhibited due to the larger size of the argon. This study illustrates the size selectivity of [NH4 ][M(HCOO)3 ] compounds between neon and argon insertion under pressure, and the effect of inclusion on the high-pressure behaviour of neon-bearing ammonium metal formates.

  9. NEON Data Products: Supporting the Validation of GCOS Essential Climate Variables

    NASA Astrophysics Data System (ADS)

    Petroy, S. B.; Fox, A. M.; Metzger, S.; Thorpe, A.; Meier, C. L.

    2014-12-01

    The National Ecological Observatory Network (NEON) is a continental-scale ecological observation platform designed to collect and disseminate data that contributes to understanding and forecasting the impacts of climate change, land use change, and invasive species on ecology. NEON will collect in-situ and airborne data over 60 sites across the US, including Alaska, Hawaii, and Puerto Rico. The NEON Biomass, Productivity, and Biogeochemistry protocols currently direct the collection of samples from distributed, gradient, and tower plots at each site, with sampling occurring either multiple times during the growing season, annually, or on three- or five-year centers (e.g. for coarse woody debris). These data are processed into a series of field-derived data products (e.g. Biogeochemistry, LAI, above ground Biomass, etc.), and when combined with the NEON airborne hyperspectral and LiDAR imagery, are used support validation efforts of algorithms for deriving vegetation characteristics from the airborne data. Sites are further characterized using airborne data combined with in-situ tower measurements, to create additional data products of interest to the GCOS community, such as Albedo and fPAR. Presented here are a summary of tower/field/airborne sampling and observation protocols and examples of provisional datasets collected at NEON sites that may be used to support the ongoing validation of GCOS Essential Climate Variables.

  10. National Ecological Observatory Network's (NEON) future role in US carbon cycling and budgets

    NASA Astrophysics Data System (ADS)

    Loescher, H. W.

    2015-12-01

    The US National Ecological Observatory Network (NEON) is a National Science Foundation investment designed to observe the impacts of large-scale environment changes on the nation's ecosystems for 30 years with rigorous consistency. NEON does this through the construction (and operations) of new physical infrastructure and data infrastructure distributed across the North American Continent. This includes 47 terrestrial and 32 aquatic sites. Key to its design is its ability to provide ecosystem-scale carbon measurements of carbon stores, fluxes, processes—and the means to scale them from the local-to regional scales via remote sensed aircraft. NEON design NEON will be collecting these carbon data as a facility and providing openly providing them. NEON will not preform any high-level synthesis, rather the carbon data is an open resource for research, private and public communities, alike. Overall, these data are also harmonized with other international carbon-based infrastructures to facilitate cross-continental understanding and global carbon syntheses. Products, engagement and harmonization of data to facilitate syntheses will be discussed.

  11. Planarization of B7- and B12- clusters by isoelectronic substitution: AlB6- and AlB11-.

    PubMed

    Romanescu, Constantin; Sergeeva, Alina P; Li, Wei-Li; Boldyrev, Alexander I; Wang, Lai-Sheng

    2011-06-08

    Small boron clusters have been shown to be planar from a series of combined photoelectron spectroscopy and theoretical studies. However, a number of boron clusters are quasiplanar, such as B(7)(-) and B(12)(-). To elucidate the nature of the nonplanarity in these clusters, we have investigated the electronic structure and chemical bonding of two isoelectronic Al-doped boron clusters, AlB(6)(-) and AlB(11)(-). Vibrationally resolved photoelectron spectra were obtained for AlB(6)(-), resulting in an accurate electron affinity (EA) for AlB(6) of 2.49 ± 0.03 eV. The photoelectron spectra of AlB(11)(-) revealed the presence of two isomers with EAs of 2.16 ± 0.03 and 2.33 ± 0.03 eV, respectively. Global minimum structures of both AlB(6)(-) and AlB(11)(-) were established from unbiased searches and comparison with the experimental data. The global minimum of AlB(6)(-) is nearly planar with a central B atom and an AlB(5) six membered ring, in contrast to that of B(7)(-), which possesses a C(2v) structure with a large distortion from planarity. Two nearly degenerate structures were found for AlB(11)(-) competing for the global minimum, in agreement with the experimental observation. One of these isomers with the lower EA can be viewed as substituting a peripheral B atom by Al in B(12)(-), which has a bowl shape with a B(9) outer ring and an out-of-plane inner B(3) triangle. The second isomer of AlB(11)(-) can be viewed as an Al atom interacting with a B(11)(-) cluster. Both isomers of AlB(11)(-) are perfectly planar. It is shown that Al substitution of a peripheral B atom in B(7)(-) and B(12)(-) induces planarization by slightly expanding the outer ring due to the larger size of Al.

  12. Theoretical Investigation of Methane Hydroxylation over Isoelectronic [FeO](2+)- and [MnO](+)-Exchanged Zeolites Activated by N2O.

    PubMed

    Mahyuddin, M Haris; Shiota, Yoshihito; Staykov, Aleksandar; Yoshizawa, Kazunari

    2017-09-05

    While the most likely structure of the active site in iron-containing zeolites has been recently identified as [FeO](2+) (Snyder et al. Nature 2016, 536, 317-321), the mechanism for the direct conversion of methane to methanol over this active species is still debatable between the direct-radical-rebound or nonradical (concerted) mechanism. Using density functional theory on periodic systems, we calculated the two reaction mechanisms over two d(4) isoelectronic systems, [FeO](2+) and [MnO](+) zeolites. We found that [FeO](2+) zeolites favor the direct-radical-rebound mechanism with low CH4 activation energies, while [MnO](+) zeolites prefer the nonradical mechanism with higher CH4 activation energies. These contrasts, despite their isoelectronic structures, are mainly due to the differences in the metal coordination number and Oα (oxo) spin density. Moreover, molecular orbital analyses suggest that the zeolite steric hindrance further degrades the reactivity of [MnO](+) zeolites toward methane. Two types of zeolite frameworks, i.e., medium-pore ZSM-5 (MFI framework) and small-pore SSZ-39 (AEI framework) zeolites, were evaluated, but no significant differences in the reactivity were found. The rate-determining reaction step is found to be methanol desorption instead of methane activation. Careful examination of the most stable sites hosting the active species and calculation for N2O decomposition over [Fe](2+)-MFI and -AEI zeolites were also performed.

  13. NEON: the first continental-scale ecological observatory with airborne remote sensing of vegetation canopy biochemistry and structure

    Treesearch

    Thomas U. Kampe; Brian R. Johnson; Michele Kuester; Michael. Keller

    2010-01-01

    The National Ecological Observatory Network (NEON) is an ecological observation platform for discovering, understanding and forecasting the impacts of climate change, land use change, and invasive species on continental-scale ecology. NEON will operate for 30 years and gather long-term data on ecological response changes and on feedbacks with the geosphere, hydrosphere...

  14. Photochemistry of the ozone-water complex in cryogenic neon, argon, and krypton matrixes.

    PubMed

    Tsuge, Masashi; Tsuji, Kazuhide; Kawai, Akio; Shibuya, Kazuhiko

    2013-12-12

    The photochemistry of ozone-water complexes and the wavelength dependence of the reactions were studied by matrix isolation FTIR spectrometry in neon, argon, and krypton matrixes. Hydrogen peroxide was formed upon the irradiation of UV light below 355 nm. Quantitative analyses of the reactant and product were performed to evaluate the matrix cage effect of the photoreaction. In argon and krypton matrixes, a bimolecular O((1)D) + H2O → H2O2 reaction was found to occur to form hydrogen peroxide, where the O((1)D) atom generated by the photolysis of ozone diffused in the cryogenic solids to encounter water. In a neon matrix, hydrogen peroxide was generated through intracage photoreaction of the ozone-water complex, indicating that a neon matrix medium is most appropriate to study the photochemistry of the ozone-water complex.

  15. Essential features of optical processes in neon-buffered submicron-thin Rb vapor cell.

    PubMed

    Hakhumyan, Grant; Sargsyan, Armen; Leroy, Claude; Pashayan-Leroy, Yevgenya; Papoyan, Aram; Sarkisyan, David

    2010-07-05

    A new submicron thin cell (STC) filled with Rb and neon gas is developed and comparison of resonant absorption with STC containing pure Rb is provided. The effect of collapse and revival of Dicke-type narrowing is still observable for the thickness L = lambda /2 and L = lambda , where lambda is a resonant laser wavelength 794 nm (D(1) line). For an ordinary Rb cm-size cell with addition of buffer gas, the velocity selective optical pumping/saturation (VSOP) resonances in saturated absorption spectra are fully suppressed if neon pressure > 0.5 Torr. A spectacular difference is that for L = lambda , VSOP resonances are still observable even when neon pressure is > or = 6 Torr. Narrow fluorescence spectra at L = lambda /2 allow one to realize online buffer gas pressure monitoring. A good agreement with theoretical model is observed.

  16. Solar wind neon from Genesis: implications for the lunar noble gas record.

    PubMed

    Grimberg, Ansgar; Baur, Heinrich; Bochsler, Peter; Bühler, Fritz; Burnett, Donald S; Hays, Charles C; Heber, Veronika S; Jurewicz, Amy J G; Wieler, Rainer

    2006-11-17

    Lunar soils have been thought to contain two solar noble gas components with distinct isotopic composition. One has been identified as implanted solar wind, the other as higher-energy solar particles. The latter was puzzling because its relative amounts were much too large compared with present-day fluxes, suggesting periodic, very high solar activity in the past. Here we show that the depth-dependent isotopic composition of neon in a metallic glass exposed on NASA's Genesis mission agrees with the expected depth profile for solar wind neon with uniform isotopic composition. Our results strongly indicate that no extra high-energy component is required and that the solar neon isotope composition of lunar samples can be explained as implantation-fractionated solar wind.

  17. A stochastic, local mode study of neon-liquid surface collision dynamics.

    PubMed

    Packwood, Daniel M; Phillips, Leon F

    2011-01-14

    Equations of motion for a fast, light rare gas atom passing over a liquid surface are derived and used to infer the dynamics of neon collisions with squalane and perfluorinated polyether surfaces from experimental data. The equations incorporate the local mode model of a liquid surface via a stochastic process and explicitly account for impulsive collisional energy loss to the surface. The equations predict angular distributions for scattering of neon that are in good quantitative agreement with experimental data. Our key dynamical conclusions are that experimental angular distributions derive mainly from local mode surface topography rather than from structural features of individual surface molecules, and that the available data for these systems can be accounted for almost exclusively by single collisions between neon atoms and the liquid surface.

  18. Demonstrating a directional detector based on neon for characterizing high energy neutrons

    NASA Astrophysics Data System (ADS)

    Hexley, Allie

    2016-03-01

    MITPC is a gas-based time projection chamber used for detecting fast, MeV-scale neutrons. The standard version of the detector relies on a mixture of 600 torr gas composed of 87.5% helium-4 and 12.5% tetrafluoromethane for precisely measuring the energy and direction of neutron-induced nuclear recoils. I describe studies performed with a prototype detector investigating the use of neon, as a replacement for helium-4, in the gas mixture. My discussion focuses on the advantages of neon as the fast neutron target for high energy neutron events (100 MeV) and a demonstration that the mixture will be effective for this event class. I show that the achievable gain and transverse diffusion of drifting electrons in the neon mixture are acceptable and that the detector uptime lost due to voltage breakdowns in the amplification plane is negligible, compared to 20% with the helium-4 mixture.

  19. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Subsonic radiation waves in neon

    NASA Astrophysics Data System (ADS)

    Loseva, T. V.; Nemchinov, I. V.

    1989-02-01

    Numerical methods are used to investigate the propagation of plane subsonic radiation waves in neon from an obstacle in the direction opposite to the incident radiation of Nd and CO2 lasers. An analysis is made of the influence of the power density of the incident radiation (in the range 10-100 MW/cm2) and of the initial density of neon (beginning from the normal valuep ρ0 up to 10ρ0) on the various characteristics of subsonic radiation waves. It is shown that waves traveling in neon can provide an effective source of radiation with a continuous spectrum and an efficiency of ~ 12-27% in the ultraviolet range (with a characteristic photon energy ~ 5-10 eV).

  20. The First Four Year's of Orthoimages from NEON's Airborne Observation Platform

    NASA Astrophysics Data System (ADS)

    Adler, J.; Gallery, W. O.

    2016-12-01

    The National Ecological Observatory Network (NEON), funded by the National Science Foundation (NSF), has been collecting orthorectified images in conjunction with lidar and spectrometer data for the past four years. The NEON project breaks up the United States into 20 regional areas from Puerto Rico to the North Slope of Alaska, with each region (Domain) typically having three specific sites of interest. Each site spans between 100km2 - 720km2 in area. Currently there are over 125,000 orthorectified images online from 6 Domains for the public and scientific community to freely download. These images are expected to assist researchers in many areas including vegetation cover, dominant vegetation type, and environmental change detection. In 2016 the NEON Airborne Observation Platform (AOP) group has collected digital imagery at 8.5 cm resolution over approximately 30 sites, for a total of 60,000 orthoimages. This presentation details the current status of the surveys conducted to date, and describes the scientific details of how NEON publishes Level 1 and Level 3 products. In particular, the onboard lidar system's contribution to the orthorectification process is outlined, in addition to the routines utilized for correcting white balance and exposure. Additionally, key flight parameters needed to produce NEON's complementary data of multi-sensor (camera/lidar/spectrometer) instruments are discussed. Problems with validating the orthoimages with the coarser resolution lidar system are addressed, to include the utilization of ground-truth locations. Lastly, methods to access NEON's publically available 10cm resolution orthoimages (in both individual image format, and in 1km by 1km tiles) are presented. A brief overview of the 2017 field season's nine new sites completes the presentation.

  1. NEON: Developing a Platform for Regional to Continental Scale Biological Inquiry

    NASA Astrophysics Data System (ADS)

    Goldman, J.

    2004-05-01

    Climate variation, introductions of alien species, and patterns of land use are some of the important interacting drivers of biological change that are affecting our nation's ecosystems. Many of these drivers operate over large spatial and temporal scales, and our understanding of how these phenomena interact to drive biological change is limited by our inability to link traditionally local and short-term ecological approaches to larger and longer scales. Similarly, our ability to forecast such changes and respond to their consequences is constrained. The National Ecological Observatory Network (NEON) is a proposed shared-use research and education platform intended to improve our capacity to understand and predict biological phenomena operating from regional to continental scales. NEON is envisioned as a system of field and laboratory-based facilities distributed across the United States, which will provide the physical infrastructure and human capabilities necessary to coordinate and integrate research and education campaigns on the following types of issues: (1) biodiversity, species composition, and ecosystem functioning; (2) ecological aspects of biogeochemical cycles; (3) ecological implications of climate change; (4) ecology and evolution of infectious disease; (5) invasive species; and (6) land use and habitat alteration. Themes such as data sharing, multidisciplinary collaboration, and the development of technologies for sensing, forecasting, and visualizing biological information are central to the NEON concept. Development of the NEON science plan and the design of the network itself are proceeding through a variety of workshops and community planning meetings. A national project office is expected to form toward the end of 2004 to lead the development and creation of NEON. Ultimately, the project office will reside within an independent national organization devoted to the coordinated operation of NEON for the scientific community.

  2. Big Data and Ecological Forecasting: Integrating NEON Observational and Sensor Data from Reach to Continent

    NASA Astrophysics Data System (ADS)

    Vance, J. M.; Goodman, K. J.; Lunch, C. K.; Fitzgerald, M.

    2015-12-01

    The ability to forecast the response of varied ecosystems to changes in climate and land use will be crucial for the management of resources and ecosystem services. Ecological forecasting presents many significant challenges within each of the aspects of data capture, assimilation, and modeling. High space-time resolution sampling is required to address the challenges of scaling from the site level to the continent. Determining the uncertainty of data used for model input and parameterization is critical for constraining the model for accurate representation. The National Ecological Observatory Network (NEON) is poised to greatly expand the scale and availability of biogeochemical and aquatic ecological data. NEON is a continental-scale facility designed to collect and disseminate data that addresses the impacts of climate change, land-use, and invasive species on ecosystem structure and function. Using a combination of standardized observational sampling and sensor measurements, NEON will provide a rich source of biogeochemical and biophysical data from 34 aquatic and 47 terrestrial sites spatially distributed across the US, including Alaska, Hawaii and Puerto Rico for 30 years. Sites were selected to be representative of major ecosystems and maximize scalability. In addition to standardizing measurements, NEON is determining the quantitative uncertainty of each data product making them well suited to constrain models. NEON aquatic data will not only serve to baseline aquatic ecology in major ecosystems but also presents opportunities to bolster Hydrologic Models as well as incorporate aquatic biogeochemical cycling into Land Surface Models. Here we present examples of published and provisional data currently available from deployed aquatic sites, as well as an overview of the full scope and release schedule of the open source ecological data to be published on the NEON web portal. Several use cases, such as whole stream metabolism, groundwater exchange, high

  3. Liquid neon heat transfer as applied to a 30 tesla cryomagnet

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Hendricks, R. C.

    1975-01-01

    A 30-tesla magnet design is studied which calls for forced convection liquid neon heat transfer in small coolant channels. The design also requires suppressing boiling by subjecting the fluid to high pressures through use of magnet coils enclosed in a pressure vessel which is maintained at the critical pressure of liquid neon. This high pressure reduces the possibility of the system flow instabilities which may occur at low pressures. The forced convection heat transfer data presented were obtained by using a blowdown technique to force the fluid to flow vertically through a resistance heated, instrumented tube.

  4. Boundary conditions on the early Sun from ancient cosmogenic neon in meteorites

    NASA Technical Reports Server (NTRS)

    Hohenberg, C. M.; Caffee, M. W.; Swindle, T. D.; Goswami, J.

    1986-01-01

    Isotopic analysis of neon from individual grains of the meteorites Murchison (CM) and Kapoeta (howardite) shows large enrichments of cosmogenic neon in grains with solar flare tracks. The quantity of this component is incompatible with galactic cosmic ray or solar cosmic ray irradiation under present conditions and is attributed to irradiation by energetic flares from an early active Sun. Handpicked grains from each meteorite were grouped according to the presence or absence of solar flare heavy ion tracks, and these four samples were analyzed with an ion counting noble gas mass spectrometer.

  5. A cost-effective approach to microporate mammalian cells with the Neon Transfection System.

    PubMed

    Brees, Chantal; Fransen, Marc

    2014-12-01

    Electroporation is one of the most efficient nonviral methods for transferring exogenous DNA into mammalian cells. However, the relatively high costs of electroporation kits and reagents temper the routine use of this fast and easy to perform technique in many laboratories. Several years ago, a new flexible and easy to operate electroporation device was launched under the name Neon Transfection System. This device uses specialized pipette tips containing gold-plated electrodes as electroporation chamber. Here we report a protocol to regenerate these expensive tips as well as some other Neon kit accessories, thereby reducing the cost of electroporation at least 10-fold. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. X-Ray Lines of Helium-Like Oxygen and Neon in the Solar Corona,

    DTIC Science & Technology

    1982-09-30

    LIKE OXYGEN AND NEON IN THE SOLAR CORONA S. PERFORMING ORO . REPORT NUMBER ______________________________________ TR-0082(2940-O1)-7 7. AUTHOR(a) M...D-A12i 438 X-RAY LINES OF HELIUM-LIKE OXGADXVOWl"IEM W rr CORONA (U) AEROSPACE CORP EL SEGUNDO CA SPACE SCIENCES LAB D L MCKENZIE ET AL. 30 SEP 82 TR...REPORT SD-TR-82-85 X-Ray Lines of Helium-Like Oxygen and Neon in the Solar Corona D. L. McKENZIE and P. B. LANDECKER Space Sciences Laboratory

  7. Cooperative lifetime reduction of single acene molecules attached to the surface of neon clusters

    NASA Astrophysics Data System (ADS)

    Müller, Markus; Izadnia, Sharareh; Vlaming, Sebastiaan M.; Eisfeld, Alexander; LaForge, Aaron; Stienkemeier, Frank

    2015-09-01

    Tetracene and pentacene molecules attached to the surface of neon clusters have been spectroscopically investigated. The fluorescence spectra indicate that the molecules are immobilized on the surface and, to a large extent, do not form complexes. By varying the number of attached molecules, laser power, or neon cluster size, we find a systematic fluorescence lifetime reduction up to a factor of 20 indicating a cooperative coupling in our system. For averaged intermolecular distances greater than 33 Å, we attribute the reduction in fluorescence lifetime to Dicke superradiance, while for smaller intermolecular distances, nonradiative decay mechanisms cause additional lifetime reduction.

  8. Electron Excitation Coefficients in Helium, Neon, Oxygen and Methane at High E/N

    SciTech Connect

    Nikitovic, Zeljka D.

    2006-12-01

    Swarm analysis is performed by comparing experimental and calculated transport coefficients. Comparisons are repeated until a satisfactory agreement is achieved after modifications of the cross sections. We have made an analysis of our excitation coefficient data for neon and methane by using detailed Monte Carlo simulation scheme. In this work we also present experimental electron excitation coefficients for other gases: helium, neon and oxygen. We used a drift tube technique to measure the absolute emission intensities in low current self sustained Townsend type discharges.

  9. Direct access to [(Mes*P)2As](-), a 1,3-diphosphaarsa-2-allyl anion, isoelectronic with the allyl anion (Mes* = 2,4,6-(t)Bu3C6H2).

    PubMed

    Dixon, Lily S H; Allen, Lucy K; Less, Robert J; Wright, Dominic S

    2014-03-21

    The reaction of As(NMe2)3 with Mes*PHLi provides a direct source of the 1,3-diphosphaarsa-2-allyl anion, [(Mes*P)2As](-) (isoelectronic with the allyl anion). The equilibrium between the E,E and E,Z isomers of this anion depends on the extent of Li(+) ion-pairing.

  10. Vacuum ultraviolet spectroscopy of the Cl sub 2 molecule trapped in pure neon, pure argon, or mixed neon--argon matrices

    SciTech Connect

    Gurtler, P. ); Kunz, H. ); Le Calve, J. )

    1989-11-15

    Synchrotron radiation excitation and emission spectra with lifetime measurements are reported for the first time in the VUV region for systems consisting of Cl{sub 2} molecules trapped in a neon matrix, an argon matrix, and mixed Ar/Ne matrices. In pure neon, the emission spectrum of the {ital D}{prime}{r arrow}{ital A}{prime} laser'' transition at 4.7 eV of the Cl{sub 2} molecule is vibrationally well resolved and constitutes an interesting example of UV spectroscopy of a matrix isolated'' molecule. In pure argon or mixed Ar/Ne matrices, new broad emissions at 4.1, 3.8, and 3.5 eV are clearly identified, which result from the specific interaction between Cl{sup *}{sub 2} and Ar and are attributed to different charge--transfer states of the ArCl{sup +}Cl{sup {minus}} entity. The Ar concentration dependence and the time-gated spectra are shown to be especially useful in interpreting the large differences observed between the pure neon and the pure argon matrix case.

  11. Experimental verification of dynamics modulation in a periodically-driven neon glow discharge plasma

    NASA Astrophysics Data System (ADS)

    Miller, P. M.; Koepke, M. E.; Gunell, H.

    2010-11-01

    Two ionization wave modes in a driven neon glow discharge alternate as the dominant mode as their response to the driving force alternates between spatiotemporal and temporal periodic pulling. This phenomenon, termed dynamics modulation, was first noted by Koepke, Weltmann, and Selcher [1], who saw two limited but representative cases and proposed a mechanism [2] by which it occurs. Dynamics modulation is reproduced experimentally in a neon glow discharge plasma. The system is periodically driven near a non-dominant mode using a narrow-band ring dye laser tuned to a wavelength near the metastable neon transition at 588.35 nm. A spatially-fixed photodiode with a narrow band filter that selectively passes the primary neon spectral line at 640 nm is used to acquire the time series of luminosity oscillations. These experimental data are used to verify the proposed mechanism and explore the resulting implications for spontaneous unidirectional mode transitions that occur with a change in discharge current.[4pt] [1] M. E. Koepke, K.-D. Weltmann, and C. A. Selcher, Bull. Am. Phys. Soc. 40, 1716 (1995).[0pt] [2] K. -D. Weltmann, M. E. Koepke, and C. A. Selcher, Phys. Rev. E 62, 2773, (2000).

  12. Mechanism of the magnetogalvanic effect in a positive neon discharge column

    SciTech Connect

    Chaika, M.P.

    1995-01-01

    The relation between the self-alignment of atomic states in a discharge and the magnetogalvanic effect observed earlier is considered. It is shown that the alignment of the neon {sup 3}P{sub 2} metastable state cannot account for the magnetogalvanic effect. It is assumed to originate from ionization from highly excited states. 12 refs., 1 fig.

  13. X-ray heating of a neon photoionized plasma experiment at Z

    NASA Astrophysics Data System (ADS)

    Mancini, R.; Lockard, T.; Mayes, D.; Loisel, G.; Bailey, J.; Rochau, G.; Abdallah, J.

    2016-10-01

    In experiments performed at the Z facility of Sandia National Laboratories a cm-scale cell filled with neon gas was driven by the burst of broadband x-rays emitted at the collapse of a wire-array z-pinch turning the gas into a photoionized plasma. Transmission spectroscopy of a narrowband portion of the x-ray flux was used to diagnose the plasma. The time-integrated data show a highly-ionized neon plasma with a rich line absorption spectrum that permits the extraction of the ionization distribution. Data analysis produced ground and low excited state areal densities and from the ratio of first-excited to ground state populations in Li-like neon a temperature of 19 +/- 4eV was extracted to characterize the x-ray heating of the plasma. To interpret this observation, we have performed modeling calculations of the spectral distribution of the x-ray drive, self-consistent modeling of electron and atomic kinetics, and radiation-hydrodynamic simulations. We found that to compute electron temperatures consistent with observation the details of the photon-energy distribution of the drive, x-ray attenuation through the cell window, and non-equilibrium collisional-radiative neon atomic kinetics need to be taken into account. This work was sponsored by DOE Office of Science Grant DE-SC0014451, and the Z Fundamental Science Program.

  14. Continental-Scale Stable Isotope Measurements at NEON to Address Ecological Processes Across Systems

    NASA Astrophysics Data System (ADS)

    Luo, H.; Goodman, K. J.; Hinckley, E. S.; West, J. B.; Williams, D. G.; Bowen, G. J.

    2013-12-01

    The National Ecological Observatory Network (NEON) is a national-scale research platform. The overarching goal of NEON is to enable understanding and forecasting of the impacts of climate change, land use change, and invasive species on aspects of continental-scale ecology (such as biodiversity, biogeochemistry, infectious diseases, ecohydrology, etc.). NEON focuses explicitly on questions that relate to grand challenges in environmental science, are relevant to large regions, and would otherwise be very difficult to address with traditional ecological approaches. The use of stable isotope approaches in ecological research has grown steadily during the last two decades. Stable isotopes at natural abundances in the environment trace and integrate the interaction between abiotic and biotic components across temporal and spatial scales. In this poster, we will present the NEON data products that incorporate stable isotope measurements in atmospheric, terrestrial, and aquatic ecosystems in North America. We further outline current questions in the natural sciences community and how these data products can be used to address continental-scale ecological questions, such as the ecological impacts of climate change, terrestrial-aquatic system linkages, land-atmosphere exchange, landscape ecohydrological processes, and linking biogeochemical cycles across systems. Specifically, we focus on the use of stable isotopes to evaluate water availability and residence times in terrestrial systems, as well as nutrient sources to terrestrial systems, and cycling across ecosystem boundaries.

  15. Cellular and molecular effects for mutation induction in normal human cells irradiated with accelerated neon ions.

    PubMed

    Suzuki, Masao; Tsuruoka, Chizuru; Kanai, Tatsuaki; Kato, Takeshi; Yatagai, Fumio; Watanabe, Masami

    2006-02-22

    We investigated the linear energy transfer (LET) dependence of mutation induction on the hypoxanthine-guanine phosphoribosyl transferase (HPRT) locus in normal human fibroblast-like cells irradiated with accelerated neon-ion beams. The cells were irradiated with neon-ion beams at various LETs ranging from 63 to 335 keV/microm. Neon-ion beams were accelerated by the Riken Ring Cyclotron at the Institute of Physical and Chemical Research in Japan. Mutation induction at the HPRT locus was detected to measure 6-thioguanine-resistant clones. The mutation spectrum of the deletion pattern of exons of mutants was analyzed using the multiplex polymerase chain reaction (PCR). The dose-response curves increased steeply up to 0.5 Gy and leveled off or decreased between 0.5 and 1.0 Gy, compared to the response to (137)Cs gamma-rays. The mutation frequency increased up to 105 keV/microm and then there was a downward trend with increasing LET values. The deletion pattern of exons was non-specific. About 75-100% of the mutants produced using LETs ranging from 63 to 335 keV/mum showed all or partial deletions of exons, while among gamma-ray-induced mutants 30% showed no deletions, 30% partial deletions and 40% complete deletions. These results suggested that the dose-response curves of neon-ion-induced mutations were dependent upon LET values, but the deletion pattern of DNA was not.

  16. Light-sensitive motile iridophores and visual pigments in the neon tetra, Paracheirodon innesi.

    PubMed

    Kasai, Akiko; Oshima, Noriko

    2006-09-01

    Although motile iridophores in the longitudinal stripes of neon tetra skin are under control of the sympathetic nervous system, they also respond to light directly and show circadian color changes. Using neon tetra skin, we found that the photoresponse of iridophores depends on light intensity, and that light near 500 nm is most effective. RT-PCR demonstrated the expression of mRNAs encoding rhodopsin and two kinds of cone opsins (Pi-green1 and Pi-green2) in neon tetra skin where the light-sensitive iridophores exist. These mRNAs are also expressed in the lateral eyes. The cone opsin genes, Pi-green1 and Pi-green2, show high similarity with the g101 and g103 genes of unique green cone opsins (belonging to the MWS/LWS group) of the blind Mexican cavefish. These results show that Pi-green1, Pi-green2, and/or rhodopsin may play important roles in the photoresponse of neon tetra iridophores, which are most sensitive to light near 500 nm.

  17. A UV laser by frequency doubling within the resonator of a helium-neon laser

    SciTech Connect

    Zhong Cantao; Li Xinzhang; Zhao Suitang; Wang Yichong

    1996-12-31

    An ultraviolet laser has been developed from the 632.8nm line of a helium-neon laser using internal frequency doubling method with a lithium iodate crystal. It generates continuous ultraviolet radiation at 316.4nm. By optimizing the optical components, a folded three-mirror resonator gave out UV radiation up to 1.5mW.

  18. Charge exchange fast neutral measurement with natural diamond detectors in neon plasma on LHD

    NASA Astrophysics Data System (ADS)

    Saida, T.; Sasao, M.; Isobe, M.; Krasilnikov, A. V.

    2003-03-01

    Charge exchange (CX) fast neutral spectra produced by ion cyclotron resonance frequency hydrogen minority heating in neon and helium majority plasmas sustained by neutral beam injection were measured with perpendicular Natural Diamond Detectors during the fifth campaign in 2002 on large helical devices (LHDs). It was observed that there were differences between fast neutral spectra shapes in neon plasma and those in helium of the same discharge condition with similar plasma parameters. Dominant CX processes in neon and helium plasmas were studied for ionization components from outside of the last closed flux surface. High-energy proton spectra were obtained by taking account of each charge state distribution and responsible charge exchange cross sections. The high-energy proton tail formations in both plasmas were similar for the same heating regime. The relaxation time tendencies of the effective temperatures of a high-energy proton have also shown no differences, indicating that the acceleration and confinement of energetic ions in LHDs are similar in neon and helium plasmas.

  19. Neon Lights up a Controversy: The Solar Ne/O Abundance

    NASA Astrophysics Data System (ADS)

    Schmelz, J. T.; Nasraoui, K.; Roames, J. K.; Lippner, L. A.; Garst, J. W.

    2005-12-01

    The standard solar model was so reliable that it could predict the existence of the massive neutrino. Helioseismology measurements were so precise that they could determine the depth of the convection zone. This agreement between theory and observation was the envy of all astrophysics-until recently, when sophisticated three-dimensional hydrodynamic calculations of the solar atmosphere reduced the metal content by a factor of almost 2. Antia & Basu suggested that a higher value of the solar neon abundance, ANe/AO=0.52, would resolve this controversy. Drake & Testa presented evidence in favor of this idea from a sample of 21 Chandra stars with enhanced values of the neon abundance, ANe/AO=0.41. In this Letter, we have analyzed solar active region spectra from the archive of the Flat Crystal Spectrometer on the Solar Maximum Mission, a NASA mission from the 1980s, as well as full-Sun spectra from the pioneering days of X-ray astronomy in the 1960s. These data are consistent with the standard neon-to-oxygen abundance value, ANe/AO=0.15 (Grevesse & Sauval). We conclude, therefore, that the enhanced-neon hypothesis will not resolve the current controversy.

  20. First-order transition between a small gap semiconductor and a ferromagnetic metal in the isoelectronic alloy FeSi1-xGex.

    PubMed

    Anisimov, V I; Hlubina, R; Korotin, M A; Mazurenko, V V; Rice, T M; Shorikov, A O; Sigrist, M

    2002-12-16

    The contrasting ground states of isoelectronic, isostructural FeSi and FeGe are explained within an extended local density approximation scheme (LDA+U) by an appropriate choice of the Coulomb repulsion U on the Fe sites. A minimal two-band model with interband interactions leads to a phase diagram for the alloys FeSi1-xGex. A mean field approximation gives a first-order transition between a small gap semiconductor and a ferromagnetic metal as a function of magnetic field, temperature, and concentration x. Unusually the transition from metal to insulator is driven by broadening, not narrowing, the bands and it is the metallic state that shows magnetic order.

  1. A DFT investigation on geometry and chemical bonding of isoelectronic Si8N6V-, Si8N6Cr, and Si8N6Mn+ clusters

    NASA Astrophysics Data System (ADS)

    Tam, Nguyen Minh; Pham, Hung Tan; Cuong, Ngo Tuan; Tung, Nguyen Thanh

    2017-10-01

    The geometric feature and chemical bonding of isoelectronic systems Si8N6Mq (M = V, Cr, Mn and q = -1, 0, 1, respectively) are investigated by means of density-functional-theory calculations. The encapsulated form is found for all ground-state structures, where the metal atom locates at the central site of the hollow Si8N6 cage. The Si8N6 cage is established by adding two Si atoms to a distorted Si6N6 prism, which is a combination of Si4N2 and Si2N4 strings. Chemical bonding of Si8N6Mq systems is explored by using the electron localization indicator and theory of atom in molecule, revealing the vital role of metal center in stabilizing the clusters.

  2. NEON Collaborative Data Collection Campaign at Pacific South West Site in California

    NASA Astrophysics Data System (ADS)

    Kampe, T. U.; Leisso, N.; Krause, K.; Musinsky, J.; Petroy, S. B.; Wasser, L. A.; Cawse-Nicholson, K.; van Aardt, J. A.; Schaaf, C.; Strahler, A. H.; Serbin, S. P.

    2013-12-01

    The National Ecological Observatory Network (NEON) is a continental-scale observatory that will collect biological, chemical and geophysical data over the continental United States in order to study biodiversity, landcover change, climate change and invasive species. In June 2013, a large-scale data collection took place over NEON's Pacific South West (PSW) site 17 in CA, USA. Data were collected in the San Joaquin Experimental Range and the Sierra National Forest. NEON's AOP (Airborne Observation Platform) acquired high spatial resolution hyperspectral data (~1m pixels), waveform lidar, discrete lidar, and RGB imagery over all three sites. A field team simultaneously collected atmospheric and vegetation inventory data, including tree locations, height, diameter-at-breast-height (DBH), species, and spectral data. The NEON collect was centered within a collaboration of multiple research entities, including NASA, Rochester Institute of Technology (RIT), University of Massachusetts (Boston; UMB, and Lowell; UML), Boston University (BU), and the University of Wisconsin, Madison (UWM). NASA's AVIRIS and MASTER sensors were flown over a wider area encompassing the NEON sites, with AVIRIS acquiring hyperspectral data (224 bands) at approximately 30m spatial resolution, and MASTER acquiring multispectral thermal data (50 bands) at approximately 50m spatial resolution. These data will be downscaled to approximate theoretical HyspIRI data (60m spatial resolution) as part of a large collection of preparatory research. Concurrently, a variety of university teams were active in the field: RIT collected ground-based lidar, leaf area index (LAI), herbaceous biomass measurements, wide-angle photographs, and spectral measurements. Data were collected over 20 80x80m sites, centered on existing 20x20m NEON sites. This data set will be used to inform synthetic scene design and to study the impact of sub-pixel structural variation on pixel-level spectral response; The BU, UMB, and UML

  3. Helium-neon laser irradiation stimulates migration and proliferation in melanocytes and induces repigmentation in segmental-type vitiligo.

    PubMed

    Yu, Hsin-Su; Wu, Chieh-Shan; Yu, Chia-Li; Kao, Ying-Hsien; Chiou, Min-Hsi

    2003-01-01

    Low-energy helium-neon lasers (632.8 nm) have been employed in a variety of clinical treatments including vitiligo management. Light-mediated reaction to low-energy laser irradiation is referred to as biostimulation rather than a thermal effect. This study sought to determine the theoretical basis and clinical evidence for the effectiveness of helium-neon lasers in treating vitiligo. Cultured keratinocytes and fibroblasts were irradiated with 0.5-1.5 J per cm2 helium-neon laser radiation. The effects of the helium-neon laser on melanocyte growth and proliferation were investigated. The results of this in vitro study revealed a significant increase in basic fibroblast growth factor release from both keratinocytes and fibroblasts and a significant increase in nerve growth factor release from keratinocytes. Medium from helium-neon laser irradiated keratinocytes stimulated [3H]thymidine uptake and proliferation of cultured melanocytes. Furthermore, melanocyte migration was enhanced either directly by helium-neon laser irradiation or indirectly by the medium derived from helium-neon laser treated keratinocytes. Thirty patients with segmental-type vitiligo on the head and/or neck were enrolled in this study. Helium-neon laser light was administered locally at 3.0 J per cm2 with point stimulation once or twice weekly. The percentage of repigmented area was used for clinical evaluation of effectiveness. After an average of 16 treatment sessions, initial repigmentation was noticed. Marked repigmentation (>50%) was observed in 60% of patients with successive treatments. Basic fibroblast growth factor is a putative melanocyte growth factor, whereas nerve growth factor is a paracrine factor for melanocyte survival in the skin. Both nerve growth factor and basic fibroblast growth factor stimulate melanocyte migration. It is reasonable to propose that helium-neon laser irradiation clearly stimulates melanocyte migration and proliferation and mitogen release for melanocyte growth

  4. NEON: High Frequency Monitoring Network for Watershed-Scale Processes and Aquatic Ecology

    NASA Astrophysics Data System (ADS)

    Vance, J. M.; Fitzgerald, M.; Parker, S. M.; Roehm, C. L.; Goodman, K. J.; Bohall, C.; Utz, R.

    2014-12-01

    Networked high frequency hydrologic and water quality measurements needed to investigate physical and biogeochemical processes at the watershed scale and create robust models are limited and lacking standardization. Determining the drivers and mechanisms of ecological changes in aquatic systems in response to natural and anthropogenic pressures is challenging due to the large amounts of terrestrial, aquatic, atmospheric, biological, chemical, and physical data it requires at varied spatiotemporal scales. The National Ecological Observatory Network (NEON) is a continental-scale infrastructure project designed to provide data to address the impacts of climate change, land-use, and invasive species on ecosystem structure and function. Using a combination of standardized continuous in situ measurements and observational sampling, the NEON Aquatic array will produce over 200 data products across its spatially-distributed field sites for 30 years to facilitate spatiotemporal analysis of the drivers of ecosystem change. Three NEON sites in Alabama were chosen to address linkages between watershed-scale processes and ecosystem changes along an eco-hydrological gradient within the Tombigbee River Basin. The NEON Aquatic design, once deployed, will include continuous measurements of surface water physical, chemical, and biological parameters, groundwater level, temperature and conductivity and local meteorology. Observational sampling will include bathymetry, water chemistry and isotopes, and a suite of organismal sampling from microbes to macroinvertebrates to vertebrates. NEON deployed a buoy to measure the temperature profile of the Black Warrior River from July - November, 2013 to determine the spatiotemporal variability across the water column from a daily to seasonal scale. In July 2014 a series of water quality profiles were performed to assess the contribution of physical and biogeochemical drivers over a diurnal cycle. Additional river transects were performed

  5. Transformational principles for NEON sampling of mammalian parasites and pathogens: a response to Springer et al. (2016)

    USDA-ARS?s Scientific Manuscript database

    The National Environmental Observatory Network (NEON) has recently released a series of protocols presented with apparently broad community support for studies of small mammals and parasites. Sampling designs were outlined outlined, collectively aimed at understanding how changing environmental cond...

  6. Shattering the myth of the resonantly photo-pumped neon-like titanium laser

    SciTech Connect

    Nilsen, J.; MacGowan, B.J.; Da Silva, L.B.; Moreno, J.C.; Koch, J.A.

    1993-08-01

    Several years ago neon-like titanium (Z = 22) was made to lase at 326 {angstrom} on the 3p {yields} 3s (J = 0 {yields} 1) transition. At the time it was suggested that the lasing may be due to resonantly photo-pumping the neon-like titanium 2p {yields} 4d lines using 3s {yields} 2p and 3d {yields} 2p lines in carbon-like and nitrogen-like titanium which results in lasing on the 3p {yields} 3s transition in neon-like titanium. The strongest argument for this explanation was that adjacent elements (scandium and vanadium) did not lase while titanium was unique in having the above mentioned resonance. In addition a prepulse was required to make the titanium lase, suggestive of the formation of a low density plasma, and the plasma was very overstripped, so the above mentioned pump lines should be quite strong for photo-pumping. We have reinvestigated this laser system and will present results which show lasing on the 3p {yields} 3s (J = 0 {yields} 1) transition in neon-like chromium (Z = 24), iron (Z = 26), and nickel (Z = 28) at 285, 255, and 231 {angstrom} respectively. This destroys the myth of titanium being unique and makes highly unlikely that the previously mentioned photo-pumping mechanism is playing a significant role in the titanium laser. The chromium, iron, and nickel experiments all require a prepulse in order to lase and our calculations suggest that the prepulse is an exciting new way to create a uniform low density plasma when illuminating a thick slab target. This allows the proper conditions for gain and laser propagation for low Z neon-like ions and may also be applicable to other systems such as low Z nickel-like ions. We also will present experiments done on other low-Z materials and offer an explanation as to how the hyperfine effect is destroying the gain of neon-like ions with odd Z.

  7. NEON: Contributing continental-scale long-term environmental data for the benefit of society

    NASA Astrophysics Data System (ADS)

    Wee, B.; Aulenbach, S.

    2011-12-01

    The National Ecological Observatory Network (NEON) is a NSF funded national investment in physical and information infrastructure. Large-scale environmental changes pose challenges that straddle environmental, economic, and social boundaries. As we develop climate adaptation strategies at the Federal, state, local, and tribal levels, accessible and usable data are essential for implementing actions that are informed by the best available information. NEON's goal is to enable understanding and forecasting of the impacts of climate change, land use change and invasive species on continental-scale ecology by providing physical and information infrastructure. The NEON framework will take standardized, long-term, coordinated measurements of related environmental variables at each of its 62 sites across the nation. These observations, collected by automated instruments, field crews, and airborne instruments, will be processed into more than 700 data products that are provided freely over the web to support research, education, and environmental management. NEON is envisioned to be an integral component of an interoperable ecosystem of credible data and information sources. Other members of this information ecosystem include Federal, commercial, and non-profit entities. NEON is actively involved with the interoperability community via forums like the Foundation for Earth Science Information Partners and the USGS Community for Data Integration in a collective effort to identify the technical standards, best practices, and organizational principles that enable the emergence of such an information ecosystem. These forums have proven to be effective innovation engines for the experimentation of new techniques that evolve into emergent standards. These standards are, for the most part, discipline agnostic. It is becoming increasingly evident that we need to include socio-economic and public health data sources in interoperability initiatives, because the dynamics of coupled

  8. Opportunities and Challenges for Education and Outreach at NEON (National Ecological Observatory Network), a new NSF Large Facility

    NASA Astrophysics Data System (ADS)

    Gram, W.; Henderson, S.; Wasser, L. A.; Goehring, L.

    2015-12-01

    As a new NSF Large Facility, NEON (the National Ecological Observatory Network) collects continental-scale ecological and environmental data to support research and education on large-scale ecological processes. The Observatory provides data, infrastructure and educational resources to scientific, educational and general public audiences. We designed NEON's Education and Outreach (E & O) activities to meet several high-level goals, including (1) facilitating public understanding of ecological science, (2) providing tools to use NEON data, (3) educating the next generation of ecologists, and (4) enhancing diversity within the ecological community. The suite of activities we developed ranges from online resources for using NEON data to a Citizen Science project to traditional undergraduate internship programs and workshops for graduate students/early career scientists. The NEON Construction Project represents one of the first large facilities that included E & O activities as set of deliverables with defined requirements in parallel to other components of construction. This approach proved to be both an opportunity to build a multifaceted E & O program in collaboration with NEON science and engineering, and a challenge as competing priorities sometimes left E & O resource development teams without necessary technical expertise. The result, however, is a robust suite of online educational resources, citizen science opportunities, and in-person training programs. Early evaluation efforts have helped us fine tune our programming to meet the needs of target audiences, including diverse undergraduate students, graduate students, scientists, faculty, edcuators, and citizen scientists. Moving into Operations, we envision an evolving suite of resources and programs that further NEON's mission and engage audiences in "doing science," both by using NEON data in a diversity of contexts and participating in our citizen science opportunities.

  9. Atlas of the Spectrum of a Platinum/Neon Hollow-Cathode Lamp in the Region 1130-4330 Å

    National Institute of Standards and Technology Data Gateway

    SRD 112 Atlas of the Spectrum of a Platinum/Neon Hollow-Cathode Lamp in the Region 1130-4330 Å (Web, free access)   Atlas of the Spectrum of a Platinum/Neon Hollow-Cathode Lamp in the Region 1130-4330 Å contains wavelengths and intensities for about 5600 lines in the region 4330 Å. An atlas plot of the spectrum is given, with the spectral lines marked and their intensities, wavelengths, and classifications listed.

  10. Coherent 70. 9-nm radiation generated in neon by frequency tripling the fifth harmonic of a Nd:YAG laser

    SciTech Connect

    Byer, R.L.; Lago, A.; Wallenstein, R.; Chen, C.; Fan, Y.X.

    1988-03-01

    Coherent radiation is produced in the XUV region of 70.9 nm by frequency tripling the fifth harmonic of Nd:YAG laser radiation in neon. BaB2O.4 was used to generate the fifth harmonic at 212.8 nm with an output pulse energy of 20 mJ and a pulse width of 5 sec. Subsequent frequency tripling in neon gas generated 10 W of peak power at 70.9 nm.

  11. Extended Calculations with Spectroscopic Accuracy: Energy Levels and Transition Properties for the Fluorine-like Isoelectronic Sequence with Z = 24-30

    NASA Astrophysics Data System (ADS)

    Si, R.; Li, S.; Guo, X. L.; Chen, Z. B.; Brage, T.; Jönsson, P.; Wang, K.; Yan, J.; Chen, C. Y.; Zou, Y. M.

    2016-12-01

    We have performed extensive multiconfiguration Dirac-Hartree-Fock calculations and second-order many-body perturbation calculations for F-like ions with Z = 24-30. Energy levels and transition rates for electric dipole (E1), electric-quadrupole (E2), electric-octupole (E3), magnetic dipole (M1), and magnetic-quadrupole (M2) transitions, as well as radiative lifetimes, are provided for the lowest 200 levels belonging to the 1{s}22{s}22{p}5, 1{s}22s2{p}6, 1{s}22{s}22{p}43l, 1{s}22s2{p}53l, 1{s}22{p}63l, and 1{s}22{s}22{p}44l configurations of each ion. The results from the two sets of calculations are in excellent agreement. Extensive comparisons are also made with other theoretical results and observed data from the CHIANTI and NIST databases. The present energies and wavelengths are believed to be accurate enough to aid line identifications involving the n = 3 and n = 4 configurations, for which observations are largely missing. The calculated wavelengths and transition data will be useful in the modeling and diagnostics of astrophysical and fusion plasmas.

  12. Calculations with spectroscopic accuracy: energies, transition rates, and Landé gJ-factors in the carbon isoelectronic sequence from Ar XIII to Zn XXV

    NASA Astrophysics Data System (ADS)

    Ekman, J.; Jönsson, P.; Gustafsson, S.; Hartman, H.; Gaigalas, G.; Godefroid, M. R.; Froese Fischer, C.

    2014-04-01

    Extensive self-consistent multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and subsequent relativistic configuration interaction calculations are performed for 262 states belonging to the 15 configurations 2s22p2, 2s2p3, 2p4, 2s22p3l, 2s2p23l, 2p33l and 2s22p4l(l = 0,1,2) in selected carbon-like ions from Ar XIII to Zn XXV. Electron correlation effects are accounted for through large configuration state function expansions. Calculated energy levels are compared with existing theoretical calculations and data from the Chianti and NIST databases. In addition, Landé gJ-factors and radiative electric dipole transition rates are given for all ions. The accuracy of the calculations are high enough to facilitate the identification of observed spectral lines. Research supported in part by the Swedish Research council, Swedish Institute and by the IUAP-Belgian State Science Policy (BriX network P7/12).Tables of energy levels and transition rates (Tables 3-22) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/564/A24

  13. Extended calculations of level and transition properties in the nitrogen isoelectronic sequence: Cr XVIII, Fe XX, Ni XXII, and Zn XXIV

    NASA Astrophysics Data System (ADS)

    Radžiūtė, L.; Ekman, J.; Jönsson, P.; Gaigalas, G.

    2015-10-01

    Extensive multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and relativistic configuration interaction (RCI) calculations are performed for 272 states of the 2s22p3, 2s2p4, 2p5, 2s22p23l, 2s2p33l, and 2p43l (l = 0,1,2) configurations in the nitrogen-like ions Cr XVIII, Fe XX, Ni XXII, and Zn XXIV. Valence, core-valence, and core-core electron correlation effects are accounted for through large configuration state function expansions. Calculated energy levels are compared with data from other calculations and with experimental data from the NIST database. Landé gJ-factors; hyperfine structures; isotope shifts; and radiative electric dipole (E1), electric quadrupole (E2), and magnetic dipole (M1) transition rates are given for all ions. The accuracy of the calculated energy levels is high enough to facilitate identification of observed spectral lines involving the 2l43l' configurations, for which experimental data are largely missing. Tables 5-21 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/582/A61

  14. Spitzer Finds Cosmic Neon and Sulfur's Sweet Spot

    NASA Astrophysics Data System (ADS)

    Rubin, Robert

    Elemental abundances are the fossil remnants of the life history of a galaxy. Abundance ratios indicate the effects of star formation and the release of nuclear processed heavy elements via planetary nebulae and supernovae, plus other mechanisms. By deriving the elemental abundances and judicious modeling, astronomers are able to determine the relative importance of these processes in the chemical evolution of a galaxy. Modeling requires the input of nucleosynthetic yields from stellar evolution and supernova calculations. Since most fusion reaction rates cannot be measured in any earthly laboratory, the observed elemental ratios provide good tests of fusion reaction rate calculations. This proposal addresses the means by which we determine elemental abundances. H II regions are the prime laboratory for the measurement of the most abundant elements- He, C, N, O, Ne, S, and Ar, (usually with respect to hydrogen)- because these elements have strong lines in the ionization states produced by the Lyman continuum photons from massive O-stars. With Spitzer's Infrared Spectrograph (IRS) Short-High (SH) module (wavelength range 9.9-19.6 microns), we have the unique opportunity to measure lines from the two ions of neon (Ne+ & Ne++) and the two most abundant ions of sulfur (S++ & S+3) that are seen in H II regions: [Ne II] 12.8, [Ne III] 15.6, [S III] 18.7, and [S IV] 10.5 microns. These co-spatial/coeval spectra enable unprecedented accuracy for the measurement of these four lines and the estimate of the Ne/S abundance ratio. In Spitzer Cycles 1, 2, and 4 we measured respectively the Ne/S ratios for the galaxies M83 (a barred spiral), M33 (a local group spiral), and NGC 6822 (a local group dwarf irregular). With other GO programs, in Cycle 1 we measured the abundances in two Milky Way H II regions & the Arched Filaments in the Galactic Center, and in Cycle 5, the Orion Nebula. We propose to estimate the Ne and S abundances in many more H II regions, both extragalactic and

  15. Angle-resolved Auger electron spectra induced by neon ion impact on aluminum

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.; Aron, P. R.

    1986-01-01

    Auger electron emission from aluminum bombarded with 1 to 5 keV neon ions was studied by angle-resolved electron spectroscopy. The position and shape of the spectral features depended on the incident ion energy, angle of ion incidence, and electron take-off angle with respect to the aluminum surface. These spectral dependencies were interpreted in terms of the Doppler shift given to the Auger electron velocity by the excited atom ejected into the vacuum. For oblique ion incidence it is concluded that a flux of high energy atoms are ejected in a direction close to the projection of the ion beam on the target surface. In addition, a new spectral feature was found and identified as due to Auger emission from excited neon in the aluminum matrix.

  16. Design study of steady-state 30-tesla liquid-neon-cooled magnet

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Brown, G. V.

    1976-01-01

    A design for a 30-tesla, liquid-neon-cooled magnet was reported which is capable of continuous operation. Cooled by nonboiling, forced-convection heat transfer to liquid neon flowing at 2.8 cu m/min in a closed, pressurized heat-transfer loop and structurally supported by a tapered structural ribbon, the tape-wound coils with a high-purity-aluminum conductor will produce over 30 teslas for 1 minute at 850 kilowatts. The magnet will have an inside diameter of 7.5 centimeters and an outside diameter of 54 centimeters. The minimum current density at design field will be 15.7 kA/sq cm.

  17. Effects of helio-neon laser radiation upon cellular cycle in a plant model

    SciTech Connect

    de Barioglio, S.R.; Fiol de Cuneo, M.; Lacuara, J.L.; Juri, H.

    1989-01-01

    The scope of this study was to investigate possible relationships between He-Neon laser radiation and mitotic and phase indices in meristematic cells of Allium cepa L. bulbs. Our results indicate that mitotic index increased after irradiation depending this modification on the time exposure and the potency of the He-Neon beam. Phase indices were also modified: frequency of prophase increased, while inter- meta- and anaphase decreased: telophases remain unchanged. These variations were significative only when the preparations were irradiated (a) with 5 mW for 10 min. or more, (b) with 10 mW or (c) when the preparations were processed 60 min. after irradiation. These findings could not be attributed to thermal changes. Modifications in RNA or protein synthesis could be responsible.

  18. Evidence of strong projectile-target-core interaction in single ionization of neon by electron impact

    SciTech Connect

    Yan, S.; Zhang, P.; Xu, S.; Ma, X.; Zhang, S. F.; Zhu, X. L.; Feng, W. T.; Liu, H. P.

    2010-11-15

    The momentum distributions of recoil ions were measured in the single ionization of neon by electron impact at incident energies between 80 and 2300 eV. It was found that there are a noticeable number of recoil ions carrying large momenta, and the relative contributions of these ions becomes more pronounced with the further decrease of incident electron energy. These observed behaviors indicate that there is a strong projectile-target-core interaction in the single-ionization reaction. By comparing our results with those of electron-neon elastic scattering, we concluded that the elastic scattering of the projectile electron on the target core plays an important role at low and intermediate collision energies.

  19. The relative abundance of neon and magnesium in the solar corona

    NASA Technical Reports Server (NTRS)

    Rugge, H. R.; Walker, A. B. C., Jr.

    1976-01-01

    A technique is proposed for specifically determining the relative solar coronal abundance of neon and magnesium. The relative abundance is calculated directly from the relative intensity of the resonance lines of Ne X (12.134A) and Mg XI (9.169A) without the need for the development of a detailed model of the thermal structure of the corona. Moderate resolution Bragg crystal spectrometer results from the OVI-10 satellite were used to determine a coronal neon to magnesium relative abundance of 1.47 + or - 0.38. The application of this technique to a recent higher resolution rocket observation gave an abundance ratio of approximately 0.93 + or - 0.15.

  20. Crystal structure and encapsulation dynamics of ice II-structured neon hydrate

    PubMed Central

    Yu, Xiaohui; Zhu, Jinlong; Du, Shiyu; Xu, Hongwu; Vogel, Sven C.; Han, Jiantao; Germann, Timothy C.; Zhang, Jianzhong; Jin, Changqing; Francisco, Joseph S.; Zhao, Yusheng

    2014-01-01

    Neon hydrate was synthesized and studied by in situ neutron diffraction at 480 MPa and temperatures ranging from 260 to 70 K. For the first time to our knowledge, we demonstrate that neon atoms can be enclathrated in water molecules to form ice II-structured hydrates. The guest Ne atoms occupy the centers of D2O channels and have substantial freedom of movement owing to the lack of direct bonding between guest molecules and host lattices. Molecular dynamics simulation confirms that the resolved structure where Ne dissolved in ice II is thermodynamically stable at 480 MPa and 260 K. The density distributions indicate that the vibration of Ne atoms is mainly in planes perpendicular to D2O channels, whereas their distributions along the channels are further constrained by interactions between adjacent Ne atoms. PMID:25002464

  1. Fast crystalline ice formation at extremely low temperature through water/neon matrix sublimation.

    PubMed

    Hama, Tetsuya; Ishizuka, Shinnosuke; Yamazaki, Tomoya; Kimura, Yuki; Kouchi, Akira; Watanabe, Naoki; Sugimoto, Toshiki; Pirronello, Valerio

    2017-07-21

    Crystalline ice formation requires water molecules to be sufficiently mobile to find and settle on the thermodynamically most stable site. Upon cooling, however, diffusion and rearrangement become increasingly kinetically difficult. Water ice grown by the condensation of water vapor in laboratory is thus generally assumed to be in a metastable amorphous form below 100 K. Here, we demonstrate the possibility of crystalline ice formation at extremely low temperature using a water/neon matrix (1/1000, 30 000 monolayers) prepared at 6 K, which is subsequently warmed to 11-12 K. In situ infrared spectroscopy revealed the assembly of the dispersed water molecules, forming crystalline ice I during the sublimation of the neon matrix for 40-250 seconds. This finding indicates that the high mobility of the water molecules during matrix sublimation can overcome the kinetic barrier to form crystals even at extremely low temperature.

  2. Angle-resolved Auger electron spectra induced by neon ion impact on aluminum

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.; Aron, P. R.

    1986-01-01

    Auger electron emission from aluminum bombarded with 1 to 5 keV neon ions was studied by angle-resolved electron spectroscopy. The position and shape of the spectral features depended on the incident ion energy, angle of ion incidence, and electron take-off angle with respect to the aluminum surface. These spectral dependencies were interpreted in terms of the Doppler shift given to the Auger electron velocity by the excited atom ejected into the vacuum. For oblique ion incidence it is concluded that a flux of high energy atoms are ejected in a direction close to the projection of the ion beam on the target surface. In addition, a new spectral feature was found and identified as due to Auger emission from excited neon in the aluminum matrix.

  3. Crystal structure and encapsulation dynamics of ice II-structured neon hydrate.

    PubMed

    Yu, Xiaohui; Zhu, Jinlong; Du, Shiyu; Xu, Hongwu; Vogel, Sven C; Han, Jiantao; Germann, Timothy C; Zhang, Jianzhong; Jin, Changqing; Francisco, Joseph S; Zhao, Yusheng

    2014-07-22

    Neon hydrate was synthesized and studied by in situ neutron diffraction at 480 MPa and temperatures ranging from 260 to 70 K. For the first time to our knowledge, we demonstrate that neon atoms can be enclathrated in water molecules to form ice II-structured hydrates. The guest Ne atoms occupy the centers of D2O channels and have substantial freedom of movement owing to the lack of direct bonding between guest molecules and host lattices. Molecular dynamics simulation confirms that the resolved structure where Ne dissolved in ice II is thermodynamically stable at 480 MPa and 260 K. The density distributions indicate that the vibration of Ne atoms is mainly in planes perpendicular to D2O channels, whereas their distributions along the channels are further constrained by interactions between adjacent Ne atoms.

  4. Prediction of thermal acoustic oscillations (TAOs) in the CLAES solid CO2/neon system

    NASA Technical Reports Server (NTRS)

    Spradley, I. E.; Yuan, S. W. K.

    1991-01-01

    Results are presented of a study initiated to investigate the possibility that the existence of thermal acoustic oscillations (TAOs) in the Cryogenic Limb Atmospheric Etalon Spectrometer (CLAES) neon plumbing system ground configuration could be the cause of higher-than-predicted heat rates measured during thermal ground testing. Tests were conducted between warm boundary temperatures ranging from 40 to 100 K, which simulated the actual test conditions of the CLAES CO2/neon system. TAOs were observed between 6 and 106 Torr, which agreed with the analytical predictions, and verified the possible existence of TAOs in the CLAES system during ground testing. The presence of TAOs was eventually confirmed in the CLAES system during a subsequent thermal test and were determined to have caused the higher heat rates measured during the prior thermal test.

  5. Electronic absorption spectra of protonated pyrene and coronene in neon matrixes.

    PubMed

    Garkusha, Iryna; Fulara, Jan; Sarre, Peter J; Maier, John P

    2011-10-13

    Protonated pyrene and coronene have been isolated in 6 K neon matrixes. The cations were produced in the reaction of the parent aromatics with protonated ethanol in a hot-cathode discharge source, mass selected, and co-deposited with neon. Three electronic transitions of the most stable isomer of protonated pyrene and four of protonated coronene were recorded. The strongest, S(1) ← S(0) transitions, are in the visible region, with onset at 487.5 nm for protonated pyrene and 695.6 nm for protonated coronene. The corresponding neutrals were also observed. The absorptions were assigned on the basis of ab initio coupled-cluster and time-dependent density functional theory calculations. The astrophysical relevance of protonated polycyclic aromatic hydrocarbons is discussed.

  6. Vibrational relaxation and collision-induced dissociation of xenon fluoride by neon

    SciTech Connect

    Wilkins, R.L.

    1989-03-01

    Rate coefficients were calculated for vibrational relaxation and collision induced dissociation of ground-state xenon fluoride in neon at temperatures between 300 and 1000 K for each of nine vibrational levels. These coefficients were calculated using a pairwise additive potential energy surface, which consists, of a Morse function for the XeF interaction and Lennard-Jones functions for the NeXe and NeF interactions. Rate coefficients are provided for temperature and v-dependences. The vibrational relaxation and dissociation processes occur by multiquanta transitions. Dissociation can take place from all v-levels, provided that the internal energy of the XeF molecule is close to the rotationless dissociation limit. The order of increase effectiveness of the various forms of energy in promoting dissociation in XeF was found to be translation-rotation-vibration. At room temperature, neon atoms were more efficient than helium atoms in the dissociation processes.

  7. Prediction of thermal acoustic oscillations (TAOs) in the CLAES solid CO2/neon system

    NASA Technical Reports Server (NTRS)

    Spradley, I. E.; Yuan, S. W. K.

    1991-01-01

    Results are presented of a study initiated to investigate the possibility that the existence of thermal acoustic oscillations (TAOs) in the Cryogenic Limb Atmospheric Etalon Spectrometer (CLAES) neon plumbing system ground configuration could be the cause of higher-than-predicted heat rates measured during thermal ground testing. Tests were conducted between warm boundary temperatures ranging from 40 to 100 K, which simulated the actual test conditions of the CLAES CO2/neon system. TAOs were observed between 6 and 106 Torr, which agreed with the analytical predictions, and verified the possible existence of TAOs in the CLAES system during ground testing. The presence of TAOs was eventually confirmed in the CLAES system during a subsequent thermal test and were determined to have caused the higher heat rates measured during the prior thermal test.

  8. Unique method of treatment for exotropia applying low-energy helium-neon laser

    NASA Astrophysics Data System (ADS)

    Bessmertnaya, Valentina

    1995-01-01

    Orthoptic treatment for exotropia applying spheroprismatic correction and low-energy helium- neon laser stimulation possesses a series of advantages to the surgical treatment. Prismatic correction has been already applied for exotropia earlier and has proven to be quite effective treating the disease and its minor complications. But in more severe cases when exotropia is accompanied by hyperphoria exceeding 3 pr Dptr and cyclotropia, prismatic correction method is not helpful enough. To cure the most complicated cases of exotropia low-energy helium- neon laser was successfully used for the first time as the only means capable of eliminating hypertropia and cyclotropia. The novelty and high efficiency of the method enables ophthalmologists to approach concomitant squint not as an eye muscular deterioration but as physiological reaction of the visual analyzer to suppress diplopia. Thus the method eliminates the cause of squint.

  9. Translating the Science of Measuring Ecosystems at a National Scale: Developing NEON's Online Learning Portal

    NASA Astrophysics Data System (ADS)

    Wasser, L. A.; Gram, W.; Goehring, L.

    2014-12-01

    "Big Data" are becoming increasingly common in many fields. The National Ecological Observatory Network (NEON) will be collecting data over the 30 years, using consistent, standardized methods across the United States. These freely available new data provide an opportunity for increased understanding of continental- and global scale processes such as changes in vegetation structure and condition, biodiversity and landuse. However, while "big data" are becoming more accessible and available, integrating big data into the university courses is challenging. New and potentially unfamiliar data types and associated processing methods, required to work with a growing diversity of available data, may warrant time and resources that present a barrier to classroom integration. Analysis of these big datasets may further present a challenge given large file sizes, and uncertainty regarding best methods to properly statistically summarize and analyze results. Finally, teaching resources, in the form of demonstrative illustrations, and other supporting media that might help teach key data concepts, take time to find and more time to develop. Available resources are often spread widely across multi-online spaces. This presentation will overview the development of NEON's collaborative University-focused online education portal. Portal content will include 1) videos and supporting graphics that explain key concepts related to NEON data products including collection methods, key metadata to consider and consideration of potential error and uncertainty surrounding data analysis; and 2) packaged "lab" activities that include supporting data to be used in an ecology, biology or earth science classroom. To facilitate broad use in classrooms, lab activities will take advantage of freely and commonly available processing tools, techniques and scripts. All NEON materials are being developed in collaboration with existing labs and organizations.

  10. Translating the Science of Measuring Ecosystems at a National Scale: NEON's Online Learning Portal

    NASA Astrophysics Data System (ADS)

    Wasser, L. A.

    2015-12-01

    "Big Data" are becoming increasingly common in many fields. The National Ecological Observatory Network (NEON) will collect data over the 30 years, using consistent, standardized methods across the United States. These freely available new data provide an opportunity for increased understanding of continental- and global scale processes such as changes in vegetation structure and condition, biodiversity and landuse. However, while "big data" are becoming more accessible and available, working with big data is challenging. New and potentially unfamiliar data types and associated processing methods, required to work with a growing diversity of available data take time and resources to learn. Analysis of these big datasets may further present a challenge given large file sizes, and uncertainty regarding best methods to properly statistically summarize and analyze results. Finally, resources that support learning these concepts and approaches, are distributed widely across multiple online spaces and may take time to find. This presentation will overview the development of NEON's collaborative University-focused online education portal. It will also cover content testing, community feedback and results from workshops using online content. Portal content is hosted in github to facilitate community input, accessibility version control. Content includes 1) videos and supporting graphics that explain key concepts related to NEON and related big spatio-temporal and 2) data tutorials that include subsets of spatio-temporal data that can be used to learn key big data skills in a self-paced approach, or that can be used as a teaching tool in the classroom or in a workshop. All resources utilize free and open data processing, visualization and analysis tools, techniques and scripts. All NEON materials are being developed in collaboration with the scientific community and are being tested via in-person workshops. Visit the portal online: www.neondataskills.org.

  11. Helium-neon lasers for remote measurements of natural gas leaks

    NASA Astrophysics Data System (ADS)

    1983-09-01

    A Differential Absorption Lidar (DIAL) system that at a distance of 15 meters can remotely sense natura gas (methane) leaks was developed. The system uses two helium-neon lasers (each emitting a different wavelength), a receiver, and an indium antimonide (InSb) photodetector cooled to 77 K. It is demonstrated the system can defect methane leaks both from an underground gas distribution system, and from sanitary landfills.

  12. Electrical characteristics for capacitively coupled radio frequency discharges of helium and neon

    NASA Astrophysics Data System (ADS)

    Tanişli, Murat; Şahin, Neslihan; Demir, Süleyman

    2017-09-01

    In this study, a symmetric radio frequency (RF) (13.56 MHz) electrode discharge system of simple geometry has been designed and made. The electrical properties of capacitive RF discharge of pure neon and pure helium have been obtained from current and voltage waveforms using different reactor designs. Calculations are done, in detail, according to the homogeneous discharge model of capacitively coupled RF. Electrical properties of bulk plasma and sheath capacitance are also investigated at low pressure using this model.

  13. Metastable and charged particle decay in neon afterglow studied by the breakdown time delay measurements

    SciTech Connect

    Markovic, V. Lj.; Gocic, S. R.; Stamenkovic, S. N.; Petrovic, Z. Lj.

    2007-10-15

    Memory effect--the long time variation of the electrical breakdown time delay on the relaxation time t{sub d}({tau}) in neon--was explained by the Ne({sup 3}P{sub 2}) (1s{sub 5}) metastable state remaining from the preceding glow [Dj. A. Bosan, M. K. Radovic, and Dj. M. Krmpotic, J. Phys. D 19, 2343 (1986)]. However, the authors neglected the quenching processes that reduce the effective lifetime of metastable states several orders of magnitude below that of the memory effect observations. In this paper the time delay measurements were carried out in neon at the pressure of 6.6 mbar in a gas tube with gold-plated copper cathode, and the approximate and exact numerical models are developed in order to study the metastable and charged particle decay in afterglow. It was found that the metastable hypothesis completely failed to explain the afterglow kinetics, which is governed by the decay of molecular neon ions and molecular nitrogen ions produced in Ne{sub 2}{sup +} collisions with nitrogen impurities; i.e., Ne{sub 2}{sup +}+N{sub 2}{yields}N{sub 2}{sup +}+2Ne. Charged particle decay is followed up to hundreds of milliseconds in afterglow, from ambipolar to the free diffusion limit. After that, the late afterglow kinetics in neon can be explained by the nitrogen atoms recombining on the cathode surface and providing secondary electrons that determine the breakdown time delay down to the cosmic rays and natural radioactivity level.

  14. Neon Isotopic Composition of the Mantle Constrained by Single Vesicles Analyses

    NASA Astrophysics Data System (ADS)

    Péron, S.; Moreira, M. A.; Colin, A. P.; Arbaret, L.; Putlitz, B.

    2015-12-01

    The origin of volatiles on Earth is still matter of debates. Noble gases turn out to be an efficient tool due to their inertness in chemical reactions and can then allow us to constrain Earth's atmosphere formation processes. In that way several studies have focused on lower mantle neon isotopes because the 20Ne/22Ne ratio is thought to reflect that of Earth's primordial components. Two models for light noble gases origin on Earth have hence been proposed: either solar wind implantation of the Earth's precursors or dissolution into the mantle of a primordial atmosphere captured from the solar nebula gas. In order to support one of the two models, we analyzed the noble gas compositions (helium, neon and argon) of oceanic island basalts from Fernandina (Galápagos hotspot). The samples are studied both by step-crushing and by laser ablation analyses of single vesicles. Results of step-crushing are consistent with those of laser ablation analyses. But the latter results permit to get rid of atmospheric contamination and to identify which crushing steps are subject to such contamination. Helium isotopic ratios R/Ra (where R is the 3He/4He ratio and Ra the atmospheric ratio) are about 23 for the two Galápagos samples. We obtain 20Ne/22Ne and 40Ar/36Ar isotopic ratios as high as 12.85-12.87 and 7000-9400 respectively for the source of the Galápagos hotspot. Hence, we show that step-crushing and laser ablation analyses are two complementary methods that should be used together to derive the noble gas ratios in uncontaminated samples. The results of neon compositions are consistent with other studies on other hotspots and support the model of solar wind implantation associated with sputtering to explain helium and neon origins on Earth.

  15. Laser-induced optogalvanic signal oscillations in miniature neon glow discharge plasma.

    PubMed

    Saini, V K

    2013-06-20

    Laser-induced optogalvanic (OG) signal oscillations detected in miniature neon glow discharge plasma are investigated using a discharge equivalent-circuit model. The damped oscillations in OG signal are generated when a pulsed dye laser is tuned to a specific neon transition (1s5→2p2) at 588.2 nm under the discharge conditions where dynamic resistance changes its sign. Penning ionization via quasi-resonant energy transfer collisions between neon gas atoms in metastable state and sputtered electrode atoms in ground state is discussed to explain the negative differential resistance properties of discharge plasma that are attributed to oscillations in the OG signal. The experimentally observed results are simulated by analyzing the behavior of an equivalent discharge-OG circuit. Good agreement between theoretically calculated and experimental results is observed. It is found that discharge plasma is more sensitive and less stable in close vicinity to dynamic resistance sign inversion, which can be useful for weak-optical-transition OG detection.

  16. The Bremen mass spectrometric facility for the measurement of helium isotopes, neon, and tritium in water.

    PubMed

    Sültenfuss, Jürgen; Roether, Wolfgang; Rhein, Monika

    2009-06-01

    We describe the mass spectrometric facility for measuring helium isotopes, neon, and tritium that has been operative at this institute since 1989, and also the sampling and sample preparation steps that precede the mass spectrometric analysis. For water samples in a near-equilibrium with atmospheric air, the facility achieves precision for (3)He/(4)He ratios of+/-0.4% or better, and+/-0.8 % or better for helium and neon concentrations. Tritium precision is typically+/-3 % and the detection limit 10 mTU ( approximately 1.2.10(-3) Bq/kg of pure water). Sample throughputs can reach some thousands per year. These achievements are enabled, among other features, by automation of the measurement procedure and by elaborate calibration, assisted by continual development in detail. To date, we have measured more than 15,000 samples for tritium and 23,000 for helium isotopes and neon, mostly in the context of oceanographic and hydrologic work. Some results of such work are outlined. Even when atmospheric tritium concentrations have become rather uniform, tritium provides water ages if (3)He data are taken concurrently. The technique can resolve tritium concentrations in waters of the pre-nuclear era.

  17. On the stability of cationic complexes of neon with helium--solving an experimental discrepancy.

    PubMed

    Bartl, Peter; Denifl, Stephan; Scheier, Paul; Echt, Olof

    2013-10-21

    Helium nanodroplets are doped with neon and ionized by electrons. The size-dependence of the ion abundance of HenNex(+), identified in high-resolution mass spectra, is deduced for complexes containing up to seven neon atoms and dozens of helium atoms. Particularly stable ions are inferred from anomalies in the abundance distributions. Two pronounced anomalies at n = 11 and 13 in the HenNe(+) series confirm drift-tube data reported by Kojima et al. [T. M. Kojima et al., Z. Phys. D, 1992, 22, 645]. The discrepancy with previously published spectra of neon-doped helium droplets, which did not reveal any abundance anomalies [T. Ruchti et al., J. Chem. Phys., 1998, 109, 10679-10687; C. A. Brindle et al., J. Chem. Phys., 2005, 123, 064312], is most likely due to limited mass resolution, which precluded unambiguous analysis of contributions from different ions with identical nominal mass. However, calculated dissociation energies of HenNe(+) reported so far do not correlate with the present data, possibly because of challenges in correctly treating the linear, asymmetric [He-Ne-He](+) ionic core in HenNe(+). Anomalies identified in the distributions of HenNex(+) for x > 1, including prominent ones at He12Ne2(+) and He14Ne2(+), may help to better understand solvation of Ne(+) and Nex(+) in helium.

  18. Helium-neon laser improves bone repair in rabbits: comparison at two anatomic sites.

    PubMed

    Peccin, Maria Stella; de Oliveira, Flavia; Muniz Renno, Ana Claudia; Pacheco de Jesus, Gustavo Protasio; Pozzi, Renan; Gomes de Moura, Carolina Foot; Giusti, Paulo Ricardo; Ribeiro, Daniel Araki

    2013-07-01

    The purpose of this study was to evaluate the influence of helium-neon laser on bone repair of femur and tibia in rabbits. For this purpose, 15 New Zealand rabbits underwent bilateral bone damage (tibia and femur) using a spherical bur. Helium-neon laser light, at a fluency of 6 J∕cm(2) and wavelength of 632.8 nm was applied on the left legs (laser group). The right tibia or femur lesions (control group) served as negative control. All sections were histopathologically analyzed using HE sections and the morphometric data from bone tissue and hyaline cartilage were achieved. Histopathological analysis showed regular bone trabeculae covered by osteoblastic cells after 1 week in the group exposed to laser therapy from femur and tibia indistinctly. After 3 weeks, the laser group showed new bone formation coming from the bony walls in the femur and tibia as well. On the 5th week, well-defined trabecula undergoing remodeling process was detected for the most intense pattern in tibia only. Morphometric analysis revealed significant statistical differences (p < 0.05) in the bone tissue for the laser-exposed group on 1st and 3rd weeks. After 5th week, bone formation was increased to tibia only. Taken together, such findings suggest that helium-neon laser is able to improve bone repair in rabbits being the most pronounced effect in tibia.

  19. Infrared spectrum of the NH4-d(n)+ cation trapped in solid neon.

    PubMed

    Jacox, Marilyn E; Thompson, Warren E

    2005-03-07

    The NH4+ cation has been stabilized in solid neon in sufficient concentration for the identification of both of its infrared-active vibrational fundamentals, which appear within a few wavenumbers of the gas-phase band centers. Systematic alteration of the concentrations and positions of introduction of NH3 and H2 in the discharge sampling experiments demonstrated that the highest yield of NH4+ resulted when both the NH3 and the H2 were introduced downstream from a discharge through pure neon. In this configuration, each of these molecules can be ionized by excited neon atoms and their resonance radiation (16.6 eV to 16.85 eV), but fragmentation is minimized. Both infrared-active vibrational fundamentals of ND4+ and several fundamentals of each of the partially deuterium-substituted isotopomers of NH4+ were also identified. Evidence is presented for complexation of NH4+ with an H atom or with one or more H2 molecules.

  20. Investigation of compression of puffing neon by deuterium current and plasma sheath in plasma focus discharge

    SciTech Connect

    Kubes, P.; Cikhardt, J.; Cikhardtova, B.; Rezac, K.; Klir, D.; Kravarik, J.; Kortanek, J.; Paduch, M.; Zielinska, E.

    2015-06-15

    This paper presents the results of the research of the influence of compressed neon, injected by the gas-puff nozzle in front of the anode axis by the deuterium current and plasma sheath on the evolution of the pinch, and neutron production at the current of 2 MA. The intense soft X-ray emission shows the presence of neon in the central region of the pinch. During the implosion and stopping of the plasma sheath, the deuterium plasma penetrates into the internal neon layer. The total neutron yield of 10{sup 10}–10{sup 11} has a similar level as in the pure deuterium shots. The neutron and hard X-ray pulses from fusion D-D reaction are as well emitted both in the phase of the stopping implosion and during the evolution of instabilities at the transformation of plasmoidal structures and constrictions composed in this configuration from both gases. The fast deuterons can be accelerated at the decay of magnetic field of the current filaments in these structures.

  1. Data Collection, Access and Presentation Technologies in the National Ecological Observatory (NEON) Design (Invited)

    NASA Astrophysics Data System (ADS)

    Aulenbach, S. M.; Berukoff, S. J.

    2010-12-01

    The National Ecological Observatory Network (NEON) will collect data across the United States on the impacts of climate change, land use change and invasive species on ecosystem functions and biodiversity. In-situ sampling and distributed sensor networks, linked by an advanced cyberinfrastructure, will collect site-based data on a variety of organisms, soils, aquatic systems, atmosphere and climate. Targeted airborne remote sensing observations made by NEON as well as geographical data sets and satellite resources produced by Federal agencies will provide data at regional and national scales. The resulting data streams, collected over a 30-year period, will be synthesized into fully traceable information products that are freely and openly accessible to all users. We provide an overview of several collection, access and presentation technologies evaluated for use by observatory systems throughout the data product life cycle. Specifically, we discuss smart phone applications for citizen scientists as well as the use of handheld devices for sample collection and reporting from the field. Protocols for storing, queuing, and retrieving data from observatory sites located throughout the nation are highlighted as are the application of standards throughout the pipelined production of data products. We discuss the automated incorporation of provenance information and digital object identifiers for published data products. The use of widgets and personalized user portals for the discovery and dissemination of NEON data products are also presented.

  2. NEON's Citizen Science Academy: Exploring online professional development courses for educators to enhance participation

    NASA Astrophysics Data System (ADS)

    Henderson, S.; Ward, D.; Wasser, L.; Meymaris, K.; Newman, S. J.

    2012-12-01

    The NEON Citizen Science Academy (CSA) (citizenscienceacademy.org) was created to explore the need for online professional development (PD) resources and opportunities that explicitly focused on citizen science in diverse educational settings. In the past decade, there has been more widespread acceptance of online PD courses as viable alternatives to face to face classes and workshops. This acceptance, along with the current proliferation of online based citizen science programs, spurred the development of the CSA dedicated to providing online courses and resources to facilitate effective implementation of citizen science programs. For the pilot, an online, self paced course for informal and formal educators was developed based on NEON' Project BudBurst (budburst.org). An intended outcome of this pilot project was the development of best practices based on lessons learned that could be used for the development of future NEON online courses and shared with the citizen science community, The pilot clearly demonstrated the interest in an online citizen science course. Initial registration far exceeded expectations and additional sessions had to be offered to meet demand. A second online course was developed and offered in the fall to similar interest. Additional courses will be offered in the winter of 2013. We will report on lessons learned and early best practices based, in large part, from field testing and feedback of over 400 educators who have taken participated in the CSA to date.

  3. Testing of a Neon Loop Heat Pipe for Large Area Cryocooling

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Robinson, Franklin Lee

    2014-01-01

    Cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks is required for future NASA missions. A cryogenic loop heat pipe (CLHP) can provide a closed-loop cooling system for this purpose and has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A neon CLHP was tested extensively in a thermal vacuum chamber using a cryopump as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components. Tests conducted included loop cool-down from the ambient temperature, startup, power cycle, heat removal capability, loop capillary limit and recovery from a dry-out, low power operation, and long duration steady state operation. The neon CLHP demonstrated robust operation. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully by applying power to both the pump and evaporator without any pre-conditioning. It could adapt to changes in the pump power andor evaporator power, and reach a new steady state very quickly. The evaporator could remove heat loads between 0.25W and 4W. When the pump capillary limit was exceeded, the loop could resume its normal function by reducing the pump power. Steady state operations were demonstrated for up to 6 hours. The ability of the neon loop to cool large areas was therefore successfully verified.

  4. Climate and Biological Drivers of Biodiversity Across the National Ecological Observatory Network (NEON)

    NASA Astrophysics Data System (ADS)

    Zarnetske, P. L.; Read, Q.; Grady, J.; Record, S.; Baiser, B.; Strecker, A.; Belmaker, J.; Beaudrot, L.; Tuanmu, M. N.

    2016-12-01

    Organism traits can help predict responses of species to climatic change and explain large-scale patterns in species distributions across geographic gradients. The new National Ecological Observatory Network's (NEON) standardized data provide an unprecedented opportunity to examine intraspecific variation for multiple traits across several taxonomic groups at a continental scale. We use organismal data from terrestrial sites within NEON to assess the degree to which assembly processes internal to ecological communities (e.g., biotic interactions, microenvironmental heterogeneity) and assembly processes external to the community that act over larger spatial scales (e.g., climate, land use) combine to influence intraspecific trait variation and affect biodiversity. Small mammals, ground beetles, and plants represent key taxonomic groups. Our findings indicate that initial plant flowering date is more variable within species at sites with higher interannual variation in climate, regardless of plant functional type. In addition, variation in body size of small mammals is higher in warmer sites. This analysis establishes a baseline from which to assess spatio-temporal changes in intraspecific trait variation with future NEON data. Resulting insights advance the ability to forecast effects of climate change on communities because they uncover key relationships between climate, intra- and interspecific variation.

  5. NEON's Mobile Deployment Platform: A research tool for integrating ecological processes across scales

    NASA Astrophysics Data System (ADS)

    Sanclements, M.

    2016-12-01

    Here we provide an update on construction of the five NEON Mobile Deployment Platforms (MDPs) as well as a description of the infrastructure and sensors available to researchers in the near future. Additionally, we include information (i.e. timelines and procedures) on requesting MDPs for PI led projects. The MDPs will provide the means to observe stochastic or spatially important events, gradients, or quantities that cannot be reliably observed using fixed location sampling (e.g. fires and floods). Due to the transient temporal and spatial nature of such events, the MDPs are designed to accommodate rapid deployment for time periods up to 1 year. Broadly, the MDPs are comprised of infrastructure and instrumentation capable of functioning individually or in conjunction with one another to support observations of ecological change, as well as education, training and outreach. More specifically, the MDPs include the capability to make tower based measures of ecosystem exchange, radiation, and precipitation in conjunction with baseline soils data such as CO2 flux, and soil temperature and moisture. An aquatics module is also available with the MDP to facilitate research integrating terrestrial and aquatic processes. Ultimately, the NEON MDPs provides a tool for linking PI led research to the continental scale data sets collected by NEON.

  6. PRESOLAR GRAINS FROM NOVAE: EVIDENCE FROM NEON AND HELIUM ISOTOPES IN COMET DUST COLLECTIONS

    SciTech Connect

    Pepin, Robert O.; Palma, Russell L.; Gehrz, Robert D.; Starrfield, Sumner

    2011-12-01

    Presolar grains in meteorites and interplanetary dust particles carry non-solar isotopic signatures pointing to origins in supernovae, giant stars, and possibly other stellar sources. There have been suggestions that some of these grains condensed in the ejecta of classical nova outbursts, but the evidence is ambiguous. We report neon and helium compositions in particles captured on stratospheric collectors flown to sample materials from comets 26P/Grigg-Skjellerup and 55P/Tempel-Tuttle that point to condensation of their gas carriers in the ejecta of a neon (ONe) nova. The absence of detectable {sup 3}He in these particles indicates space exposure to solar wind irradiation of a few decades at most, consistent with origins in cometary dust streams. Measured {sup 4}He/{sup 20}Ne, {sup 20}Ne/{sup 22}Ne, {sup 21}Ne/{sup 22}Ne, and {sup 20}Ne/{sup 21}Ne isotope ratios, and a low upper limit on {sup 3}He/{sup 4}He, are in accord with calculations of nucleosynthesis in neon nova outbursts. Of these, the uniquely low {sup 4}He/{sup 20}Ne and high {sup 20}Ne/{sup 22}Ne ratios are the most diagnostic, reflecting the large predicted {sup 20}Ne abundances in the ejecta of such novae. The correspondence of measured Ne and He compositions in cometary matter with theoretical predictions is evidence for the presence of presolar grains from novae in the early solar system.

  7. Helium-neon laser preirradiation induces protection against UVC radiation in wild-type E. coli strain K12AB1157.

    PubMed

    Kohli, R; Gupta, P K; Dube, A

    2000-02-01

    We have observed that preirradiation with a helium-neon laser (632.8 nm) induces protection against UVC radiation in wild-type E. coli strain K12AB1157. The magnitude of protection was found to depend on the helium-neon laser irradiance, exposure time, and period of incubation between helium-neon laser exposure and subsequent UVC irradiation. The optimum values for dose, irradiance and interval between the two exposures were found to be 7 kJ/m(2), 100 W/m(2) and 1 h, respectively. The possible involvement of singlet oxygen in the helium-neon laser-induced protection is also discussed.

  8. Developing a Scalable Remote Sampling Design for the NEON Airborne Observation Platform (AOP)

    NASA Astrophysics Data System (ADS)

    Musinsky, J.; Wasser, L. A.; Kampe, T. U.; Leisso, N.; Krause, K.; Petroy, S. B.; Cawse-Nicholson, K.; van Aardt, J. A.; Serbin, S.

    2013-12-01

    The National Ecological Observatory Network (NEON) airborne observation platform (AOP) will collect co-registered high-resolution hyperspectral imagery, discrete and waveform LiDAR, and high-resolution digital photography for more than 60 terrestrial and 23 aquatic sites spread across the continental United States, Puerto Rico, Alaska and Hawaii on an annual basis over the next 30 years. These data, to be made freely available to the public, will facilitate the scaling of field-based biological, physical and chemical measurements to regional and continental scales, enabling a better understanding of the relationships between climate variability and change, land use change and invasive species, and their ecological consequences in areas not directly sampled by the NEON facilities. However, successful up-scaling of in situ measurements requires a flight sampling design that captures environmental heterogeneity and diversity (i.e., ecological and topographic gradients), is sensitive to temporal system variation (e.g., phenology), and can respond to major disturbance events. Alignment of airborne campaigns - composed of two payloads for nominal science acquisitions and one payload for PI-driven rapid-response campaigns -- with other ground, airborne (e.g., AVIRIS) and satellite (e.g., Landsat, MODIS) collections will further facilitate scaling between sensors and data sources of varying spatial and spectral resolution and extent. This presentation will discuss the approach, challenges and future goals associated with the development of NEON AOP's sampling design, using examples from the 2013 nominal flight campaigns in the Central Plains (NEON Domain 10) and the Pacific Southwest (Domain 17), and the rapid response flight campaign of the High Park Fire site outside of Fort Collins, CO. Determination of the specific flight coverage areas for each campaign involved analysis of the landscape scale ecological, geophysical and bioclimatic attributes and trends most closely

  9. Improving the accuracy of helium and neon measurements in ocean waters

    NASA Astrophysics Data System (ADS)

    Vogt, M.; Roether, W.; Vogel, S.; Sueltenfuss, J.

    2012-04-01

    The helium and neon solubility disequilibria across the ocean-atmosphere interface serve to study the physics of air-sea gas exchange, but the effect is small so that only high-accuracy data give useful results. Weak points are measurement calibration and uncertain solubility equilibrium values in seawater, especially so for the helium isotopes. Calibration: The classical calibration of mass spectrometric helium and neon measurements uses aliquots of atmospheric air, which is convenient but limited in accuracy and long-term stability. Our alternative is to use water samples equilibrated with undisturbed air, so that their mass can be converted into equivalent volumes of air using a solubility function. In this way, the samples allow a precise recalibration of the air aliquots. A bias relative to regular samples is excluded because the equilibrated water is subjected to exactly the same treatment. The equilibration unit has a water capacity of 4.5 liters. The water is circulated over exchange mats, yielding full air-water equilibrium within two hours, and temperature, pressure, and humidity are precisely controlled. In consequence, we achieve solubility equilibrium within ± 0.03%, so that high accuracy and long-term stability of the calibration are guaranteed. The solubility equilibrium values are more uncertain, but a biased value will only introduce a common shift to the data, i.e., it will not affect the internal consistency of the calibration. The new calibration mode will also enable efficient intercalibration between laboratories. Solubility determination and sampling procedures: We shall use the equilibration unit to obtain solubility functions of helium and neon in distilled water and seawater with a projected accuracy of ± 0.2%. One measure to achieve this is to compare the mass spectrometric signals of the water and the air phase directly. In this context, we developed a procedure to sample water into glass ampoules to be flame-sealed. They are filled

  10. Neon isotopic composition of the mantle constrained by single vesicle analyses

    NASA Astrophysics Data System (ADS)

    Péron, Sandrine; Moreira, Manuel; Colin, Aurélia; Arbaret, Laurent; Putlitz, Benita; Kurz, Mark D.

    2016-09-01

    The origin of volatiles on Earth is still a matter of debate. Noble gases are an efficient geochemical tool to constrain Earth formation processes due to their inertness. Several studies have focused on the neon isotopic composition of the lower mantle because the 20Ne/22Ne ratio is thought to reflect that of Earth's primordial components. Two models to explain the origin of light noble gases on Earth have been proposed: either solar wind implantation onto the Earth's solid precursors or dissolution into the mantle of a primordial atmosphere captured from solar nebula gas. In order to test these two models, we analyzed the noble gas compositions (helium, neon and argon) of two submarine oceanic island basalt glasses from Fernandina volcano (Galápagos archipelago), which have among the most primitive/unradiogenic terrestrial helium and neon isotopic compositions. Several sample pieces are studied both by step-crushing and by laser ablation analyses of single vesicles. Results of step-crushing are consistent with those of laser ablation analyses, but the latter results provide new insights into the origin of atmospheric contamination. The single-vesicle laser-ablation measurements overlap with the step crushing results, but have systematically higher 40Ar/36Ar, and 3He/36Ar, suggesting less atmospheric contamination using this method. The single vesicle data therefore suggest that atmospheric contamination is introduced by exposure to the modern atmosphere, after sample collection. 3He/4He values are about 23 times the atmospheric ratio (R/Ra) for the two Fernandina (Galápagos) samples, in agreement with previous studies. We obtain 20Ne/22Ne and 40Ar/36Ar isotopic ratios as high as 12.91 and 9400, respectively, for the mantle source of the Galápagos hotspot. The new data show that step-crushing and laser ablation analyses are complementary methods that should be used together to derive the noble gas ratios in uncontaminated samples. The results of neon

  11. NEON AND OXYGEN ABUNDANCES AND ABUNDANCE RATIO IN THE SOLAR CORONA

    SciTech Connect

    Landi, E.; Testa, P.

    2015-02-20

    In this work we determine the Ne/O abundance ratio from Solar and Heliospheric Observatory (SOHO)/Solar Ultraviolet Measurement of Emitted Radiation (SUMER) off-disk observations of quiescent streamers over the 1996-2008 period. We find that the Ne/O ratio is approximately constant over solar cycle 23 from 1996 to 2005, at a value of 0.099 ± 0.017; this value is lower than the transition region determinations from the quiet Sun used to infer the neon photospheric abundance from the oxygen photospheric abundance. Also, the Ne/O ratio we determined from SUMER is in excellent agreement with in situ determinations from ACE/SWICS. In 2005-2008, the Ne/O abundance ratio increased with time and reached 0.25 ± 0.05, following the same trend found in the slowest wind analyzed by ACE/SWICS. Further, we measure the absolute abundance in the corona for both oxygen and neon from the data set of 1996 November 22, obtaining A {sub o} = 8.99 ± 0.04 and A {sub Ne} = 7.92 ± 0.03, and we find that both elements are affected by the first ionization potential (FIP) effect, with oxygen being enhanced by a factor of 1.4-2.1 over its photospheric abundance, and neon being changed by a factor of 0.75-1.20. We conclude that the Ne/O ratio is not constant in the solar atmosphere, both in time and at different heights, and that it cannot be reliably used to infer the neon abundance in the photosphere. Also, we argue that the FIP effect was less effective during the minimum of solar cycle 24, and that the Ne/O = 0.25 ± 0.05 value measured at that time is closer to the true photospheric value, leading to a neon photospheric abundance larger than assumed by ≈40%. We discuss the implications of these results for the solar abundance problem, for the FIP effect, and for the identification of the source regions of the solar wind.

  12. Are oxygen and neon enriched in PNe and is the current solar Ne/O abundance ratio underestimated?

    NASA Astrophysics Data System (ADS)

    Wang, W.; Liu, X.-W.

    2008-09-01

    A thorough critical literature survey has been carried out for reliable measurements of oxygen and neon abundances of planetary nebulae (PNe) and HII regions. By contrasting the results of PNe and of HII regions, we aim to address the issues of the evolution of oxygen and neon in the interstellar medium (ISM) and in the late evolutionary phases of low- and intermediate-mass stars (LIMS), as well as the currently hotly disputed solar Ne/O abundance ratio. Through the comparisons, we find that neon abundance and Ne/O ratio increase with increasing oxygen abundance in both types of nebulae, with positive correlation coefficients larger than 0.75. The correlations suggest different enrichment mechanisms for oxygen and neon in the ISM, in the sense that the growth of neon is delayed compared to oxygen. The differences of abundances between PNe and HII regions are mainly attributed to the results of nucleosynthesis and dredge-up processes that occurred in the progenitor stars of PNe. We find that both these α-elements are significantly enriched at low metallicity (initial oxygen abundance <~8.0) but not at metallicity higher than the Small Magellanic Cloud (SMC). The fact that Ne/O ratios measured in PNe are almost the same as those in HII regions, regardless of the metallicity, suggest a very similar production mechanism of neon and oxygen in intermediate-mass stars (IMS) of low initial metallicities and in more massive stars, a conjecture that requires verification by further theoretical studies. This result also strongly suggests that both the solar neon abundance and the Ne/O ratio should be revised upwards by ~0.22dex from the Asplund, Grevesse & Sauval values or by ~0.14dex from the Grevesse & Sauval values.

  13. Rapid healing of gingival incisions by the helium-neon diode laser.

    PubMed

    Neiburger, E J

    1999-01-01

    Fifty-eight extraction patients had one of two gingival flap incisions lased with a 1.4 mw helium-neon (670 nm) diode laser for 30 seconds (fluence = 0.34 J/cm2). Healing rates were evaluated clinically and photographically. Sixty-nine percent of the irradiated incisions healed faster than the control incisions. No significant difference in healing was noted when patients were compared by age, gender, race, and anatomic location of the incision. This study concludes that helium-neon diode lasers, at the previously mentioned energy level, increase the rate of gingival wound healing in 69 percent of patients, without any side effects. For the last 30 years, low-power lasers in dentistry have appeared to stimulate healing rates and increase the rate of repair of injured tissue. Helium-neon and similar lasers emit light in the red (600-700 nm) spectrums and produce energy densities (fluences) below 20 Joules/cm2. They have been studied in a variety of animal tissue culture and human evaluations to determine their ability to increase the rates of wound healing by biostimulation. Over the last three decades, researchers have found that ruby and gas helium-neon (low-power laser radiation) have a biostimulatory effect on living tissue. Studies show that under specific conditions, red spectrum laser light speeds the healing of wounds. Photons from the red light lasers, which include ruby lasers (694 nm), helium-neon gas lasers (632 nm), and helium-neon diode lasers (650-670 nm), appear to stimulate rapid epithelialization and fibroblast (collagen) proliferation in animal and human tissue cultures. Low-power lasers have been reported to reduce post-extraction pain and swelling and to increase rates of wound healing (including scar formation, phagocytosis) in cell culture, animal, and human clinical studies. The new, compact, and inexpensive (under $50) helium-neon diode lasers have produced similar effects. These FDA Class IIIa lasers have no hazards associated with them

  14. Effects of isoelectronic Ru substitution at the Fe site on the energy gaps of optimally F-doped SmFeAsO

    NASA Astrophysics Data System (ADS)

    Daghero, D.; Tortello, M.; Ummarino, G. A.; Stepanov, V. A.; Bernardini, F.; Tropeano, M.; Putti, M.; Gonnelli, R. S.

    2012-08-01

    We studied the effects of isoelectronic Ru substitution at the Fe site on the energy gaps of optimally F-doped SmFeAsO by means of point-contact Andreev-reflection spectroscopy. The results show that the SmFe1-xRuxAsO0.85F0.15 system keeps a multigap character at least up to x = 0.50, and that the gap amplitudes Δ1 and Δ2 scale almost linearly with the local critical temperature {T}_{{c}}^{A}. The gap ratios 2Δi/kBTc remain approximately constant only as long as Tc ≥ 30 K, and increase dramatically when Tc decreases further. This trend seems to be common to many Fe-based superconductors, irrespective of their family. Based on first-principle calculations of the bandstructure and of the density of states projected on the different bands, we show that this trend, as well as the Tc dependence of the gaps and the reduction of Tc upon Ru doping, can be explained within an effective three-band Eliashberg model as being due to a suppression of the superfluid density at finite temperature that, in turn, modifies the temperature dependence of the characteristic spin-fluctuation energy.

  15. 1s22p3 and 1s22s23l, l = s,p,d, excited states of boron isoelectronic series from explicitly correlated wave functions.

    PubMed

    Gálvez, F J; Buendía, E; Sarsa, A

    2005-07-15

    For some members of the boron isoelectronic series and starting from explicitly correlated wave functions, six low-lying excited states have been studied. Three of them arise from the 1s(2)2p(3) configuration, and the other three from the 1s(2)2s(2)3l, l = s,p,d, configurations. This work follows a previous one on both the 1s(2)2s(2)2p-(2)P ground state and the four excited states coming from the 1s(2)2s2p(2) configuration. Energies, one- and two-body densities in position space and some other two-body properties in position and momentum spaces have been obtained. A systematic analysis of the energetic ordering of the states as a function of the total orbital angular momentum and spin is performed in terms of the electron-nucleus and electron-electron potential energies and the role of the angular correlation is discussed. All calculations have been carried out by using the Monte Carlo algorithm.

  16. Relative energies, structures, vibrational frequencies, and electronic spectra of pyrylium cation, an oxygen-containing carbocyclic ring isoelectronic with benzene, and its isomers

    NASA Astrophysics Data System (ADS)

    Bera, Partha P.; Head-Gordon, Martin; Lee, Timothy J.

    2013-11-01

    We have studied relative energies, structures, rotational, vibrational, and electronic spectra of the pyrylium cation, an oxygen-containing six-membered carbocyclic ring, and its six isomers, using ab initio quantum chemical methods. Isoelectronic with benzene, the pyrylium cation has a benzenoid structure and is the global minimum on the singlet potential energy surface of C5H5O+. The second lowest energy isomer, the furfuryl cation, has a five membered backbone akin to a sugar, and is only 16 kcal mol-1 above the global minimum computed using coupled cluster theory with singles, doubles, and perturbative triple excitations (CCSD(T)) with the correlation consistent cc-pVTZ basis set. Other isomers are 25, 26, 37, 60, and 65 kcal mol-1 above the global minimum, respectively, at the same level of theory. Lower level methods such as density functional theory (B3LYP) and second order Møller-Plesset perturbation theory performed well when tested against the CCSD(T) results. The pyrylium and furfuryl cations, although separated by only 16 kcal mol-1, are not easily interconverted, as multiple bonds must be broken and formed, and the existence of more than one transition state is likely. Additionally, we have also investigated the asymptotes for the barrierless ion-molecule association of molecules known to exist in the interstellar medium that may lead to formation of the pyrylium cation.

  17. DFT Study of the Reaction Mechanisms of Carbon Dioxide and its Isoelectronic Molecules CS2 and OCS Dissolved in Pyrrolidinium and Imidazolium Acetate Ionic Liquids.

    PubMed

    Danten, Y; Cabaço, M I; Coutinho, J A P; Pinaud, Noël; Besnard, M

    2016-06-16

    The reaction mechanisms of CO2 and its isoelectronic molecules OCS and CS2 dissolved in N-butyl-N-methylpyrrolidinium acetate and in 1-butyl-3-methylimidazolium acetate were investigated by DFT calculations in "gas phase". The analysis of predicted multistep pathways allowed calculating energies of reaction and energy barriers of the processes. The major role played by the acetate anion in the degradation of the solutes CS2 and OCS as well as in the capture of OCS and CO2 by the imidazolium ring is highlighted. In both ionic liquids, this anion governs the conversion of CS2 into OCS and of OCS into CO2 through interatomic S-O exchanges between the anion and the solutes with formation of thioacetate anions. In imidazolium acetate, the selective capture of CS2 and OCS by the imidazolium ring competes with the S-O exchanges. From the calculated values of the energy barriers a basicity scale of the anions is proposed. The (13)C NMR chemical shifts of the predicted adducts were calculated and agree well with the experimental observations. It is argued that the scenario issued from the calculated pathways is shown qualitatively to be independent from the functionals and basis set used, constitute a valuable tool in the understanding of chemical reactions taking place in liquid phase.

  18. Minimum alveolar concentrations of noble gases, nitrogen, and sulfur hexafluoride in rats: helium and neon as nonimmobilizers (nonanesthetics)

    PubMed

    Koblin, D D; Fang, Z; Eger, E I; Laster, M J; Gong, D; Ionescu, P; Halsey, M J; Trudell, J R

    1998-08-01

    We assessed the anesthetic properties of helium and neon at hyperbaric pressures by testing their capacity to decrease anesthetic requirement for desflurane using electrical stimulation of the tail as the anesthetic endpoint (i.e., the minimum alveolar anesthetic concentration [MAC]) in rats. Partial pressures of helium or neon near those predicted to produce anesthesia by the Meyer-Overton hypothesis (approximately 80-90 atm), tended to increase desflurane MAC, and these partial pressures of helium and neon produced convulsions when administered alone. In contrast, the noble gases argon, krypton, and xenon were anesthetic with mean MAC values of (+/- SD) of 27.0 +/- 2.6, 7.31 +/- 0.54, and 1.61 +/- 0.17 atm, respectively. Because the lethal partial pressures of nitrogen and sulfur hexafluoride overlapped their anesthetic partial pressures, MAC values were determined for these gases by additivity studies with desflurane. Nitrogen and sulfur hexafluoride MAC values were estimated to be 110 and 14.6 atm, respectively. Of the gases with anesthetic properties, nitrogen deviated the most from the Meyer-Overton hypothesis. It has been thought that the high pressures of helium and neon that might be needed to produce anesthesia antagonize their anesthetic properties (pressure reversal of anesthesia). We propose an alternative explanation: like other compounds with a low affinity to water, helium and neon are intrinsically without anesthetic effect.

  19. Slow Interatomic Coulombic Decay of Multiply Excited Neon Clusters

    NASA Astrophysics Data System (ADS)

    Iablonskyi, D.; Nagaya, K.; Fukuzawa, H.; Motomura, K.; Kumagai, Y.; Mondal, S.; Tachibana, T.; Takanashi, T.; Nishiyama, T.; Matsunami, K.; Johnsson, P.; Piseri, P.; Sansone, G.; Dubrouil, A.; Reduzzi, M.; Carpeggiani, P.; Vozzi, C.; Devetta, M.; Negro, M.; Calegari, F.; Trabattoni, A.; Castrovilli, M. C.; Faccialà, D.; Ovcharenko, Y.; Möller, T.; Mudrich, M.; Stienkemeier, F.; Coreno, M.; Alagia, M.; Schütte, B.; Berrah, N.; Kuleff, A. I.; Jabbari, G.; Callegari, C.; Plekan, O.; Finetti, P.; Spezzani, C.; Ferrari, E.; Allaria, E.; Penco, G.; Serpico, C.; De Ninno, G.; Nikolov, I.; Diviacco, B.; Di Mitri, S.; Giannessi, L.; Prince, K. C.; Ueda, K.

    2016-12-01

    Ne clusters (˜5000 atoms ) were resonantly excited (2 p →3 s ) by intense free electron laser (FEL) radiation at FERMI. Such multiply excited clusters can decay nonradiatively via energy exchange between at least two neighboring excited atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites of the Ne clusters were probed. We found that the relaxation of cluster surface atoms proceeds via a sequence of interatomic or intermolecular Coulombic decay (ICD) processes while ICD of bulk atoms is additionally affected by the surrounding excited medium via inelastic electron scattering. For both cases, cluster excitations relax to atomic states prior to ICD, showing that this kind of ICD is rather slow (picosecond range). Controlling the average number of excitations per cluster via the FEL intensity allows a coarse tuning of the ICD rate.

  20. Slow Interatomic Coulombic Decay of Multiply Excited Neon Clusters.

    PubMed

    Iablonskyi, D; Nagaya, K; Fukuzawa, H; Motomura, K; Kumagai, Y; Mondal, S; Tachibana, T; Takanashi, T; Nishiyama, T; Matsunami, K; Johnsson, P; Piseri, P; Sansone, G; Dubrouil, A; Reduzzi, M; Carpeggiani, P; Vozzi, C; Devetta, M; Negro, M; Calegari, F; Trabattoni, A; Castrovilli, M C; Faccialà, D; Ovcharenko, Y; Möller, T; Mudrich, M; Stienkemeier, F; Coreno, M; Alagia, M; Schütte, B; Berrah, N; Kuleff, A I; Jabbari, G; Callegari, C; Plekan, O; Finetti, P; Spezzani, C; Ferrari, E; Allaria, E; Penco, G; Serpico, C; De Ninno, G; Nikolov, I; Diviacco, B; Di Mitri, S; Giannessi, L; Prince, K C; Ueda, K

    2016-12-30

    Ne clusters (∼5000  atoms) were resonantly excited (2p→3s) by intense free electron laser (FEL) radiation at FERMI. Such multiply excited clusters can decay nonradiatively via energy exchange between at least two neighboring excited atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites of the Ne clusters were probed. We found that the relaxation of cluster surface atoms proceeds via a sequence of interatomic or intermolecular Coulombic decay (ICD) processes while ICD of bulk atoms is additionally affected by the surrounding excited medium via inelastic electron scattering. For both cases, cluster excitations relax to atomic states prior to ICD, showing that this kind of ICD is rather slow (picosecond range). Controlling the average number of excitations per cluster via the FEL intensity allows a coarse tuning of the ICD rate.

  1. Canopy Biomass Lidar (CBL) Acquisitions at NEON and TERN Forest Sites

    NASA Astrophysics Data System (ADS)

    Schaaf, C.; Paynter, I.; Saenz, E.; Peri, F.; Wang, Z.; Erb, A.; Yang, X.; Strahler, A. H.; Li, Z.; van Aardt, J. A.; Kelbe, D.; Romanczyk, P.; Cawse-Nicholson, K.; Krause, K.; Leisso, N.; Kampe, T. U.; Meier, C. L.; Ritz, C.; Chakrabarti, S.; Cook, T.; Howe, G.; Martel, J.; Hewawasam, K.; Douglas, E. S.; Newnham, G.; Schaefer, M.; Armston, J.; Muir, J.; Tindall, D.; Phinn, S. R.

    2013-12-01

    Terrestrial Laser Scanning (TLS) offers the ability to capture complex forest structure through 3D reconstruction of multiple laser return point clouds. These reconstructions provide detailed information on understory, mid-story and canopy structure and allow quantification of important ecosystem factors such as biomass, vegetation productivity, forest health and response to disturbance. Used in conjunction with airborne lidar and satellite imaging, TLS is a powerful calibration/validation tool for improved regional scale ecological surveying and modeling. Repeated deployments facilitate the estimation of growth rates, nutrient fluxes, and other essential parameters in global scale climate and biogeochemic modeling. Routine TLS acquisitions at long-term research sites provide an opportunity to capture temporal variations due to natural and anthropogenic effects. While discrete return and full waveform TLS instruments (such as the Dual Wavelength Echidna Lidar (DWEL)) are increasingly being deployed, there is also a need for high speed, low-cost, highly portable TLS instruments to augment these more powerful, high resolution lidars. The Canopy Biomass Lidar (CBL) is a light, fast-scanning, time-of-flight, 905nm, TLS instrument, conceived by the Katholieke Universiteit Leuven (KUL) and refined by the Rochester Institute of Technology (RIT). Two CBLs, constructed by the University of Massachusetts Boston, were deployed alongside the full waveform DWEL (developed by Boston University, University of Massachusetts Lowell, University of Massachusetts Boston, and the Commonwealth Scientific and Industrial Research Organisation (CSIRO)) during the June 2013 NEON Airborne Observation Platform (AOP) campaign in the Sierra National Forest, CA. Three sites were characterized by both the CBLs and the DWEL in the Soaproot and Teakettle regions (where relocatable NEON towers will be situated). Up to 5 multiple scans were acquired by the DWEL, with an additional 8-12 scans obtained

  2. Mitigated blistering and deuterium retention in tungsten exposed to high-flux deuterium–neon mixed plasmas

    NASA Astrophysics Data System (ADS)

    Cheng, L.; De Temmerman, G.; Morgan, T. W.; Schwarz-Selinger, T.; Yuan, Y.; Zhou, H. B.; Wang, B.; Zhang, Y.; Lu, G. H.

    2017-04-01

    Surface morphology and deuterium retention in tungsten exposed at surface temperature of ~550 K to mixed deuterium–neon plasmas of different neon concentrations are investigated. It is found that the addition of neon up to 20% mitigates blistering on the surface. Cross-section view of the surface shows the formation of pores near the surface in the depth less than 100 nm. Deuterium depth profile is featured by an enhanced deuterium concentration within a depth of 16 nm but a mitigated penetration in depth larger than 1 µm. Deuterium retention is reduced by up to a factor of four. It is suggested the open pores formed in the surface serves as an escaping channel, mitigates deuterium penetration towards bulk and retention in the bulk.

  3. Aquatic Biogeochemical Prototype Activities at the National Ecological Observatory Network (NEON)

    NASA Astrophysics Data System (ADS)

    Goodman, K. J.; Powell, H.; Cilke, T.; Price, A.

    2010-12-01

    NEON is currently prototyping select data collections in order to develop robust protocols and procedures to be used across a gradient of stream systems, evaluating morphological mapping tools, and designing lightweight equipment and secure, stable, non-intrusive sensor installations. Here we present the status of the Aquatic prototype efforts that are occurring at the D15 Candidate Core Aquatic site: Red Butte Creek, Utah. Prototype activities include discharge and reaeration measurements, development of a stream reaeration rating curve, and water chemistry sampling. We are measuring reaeration, a measure of gas exchange across the air-water interface, using a continuous injection of SF6, an inert gas. In addition, Cl-, a conservative tracer, is added to the stream to account for dilution by groundwater inputs. As part of the NEON Prototype effort, we re-designed a lightweight, easy-to- use pump system for the addition of this conservative tracer during reaeration measurements. This pump, which costs a fraction of commercially available pumps, has performed well during field-testing and meets NEON’s needs and requirements for the injection of the conservative tracer. The NEON prototype efforts will help ensure that the data collected across the Observatory, including the 36 aquatic sites across 19 ecoclimatic domains, will enable researchers to investigate and model ecosystems response to climate change and landuse change at multiple spatial and temporal scales. The Observatory will collect data from both in-situ sensors and field data collections to produce measurements using consistent and standardized procedures and protocols across the United States. During Observatory Operations, these data will be available to the public on the web in near-real time.

  4. Another neon nova - Early infrared photometry and spectroscopy of Nova Cygni 1992

    NASA Technical Reports Server (NTRS)

    Hayward, T. L.; Gehrz, R. D.; Miles, J. W.; Houck, J. R.

    1992-01-01

    Infrared photometry and spectrophotometry of Nova Cygni 1992 taken within 54 days of its eruption show a strong 12.8-micron Ne II forbidden emission line as well as hydrogen recombination lines. Spectra with lambda/Delta lambda of about 2000 resolve the Ne II forbidden and 12.37-micron Hu-alpha lines with about 2200 km/s (FWHM). The Ne II forbidden line shows multiple velocity components. The amount of forbidden Ne II required to produce the observed emission feature exceeds the solar abundance of neon by at least a factor of 4.

  5. Coverage-dependent quantum versus classical scattering of thermal neon atoms from Li/Cu(100).

    PubMed

    Maclaren, D A; Huang, C; Levi, A C; Allison, W

    2008-09-07

    We show that subtle variations in surface structure can enhance quantum scattering and quench atom-surface energy transfer. The scattering of thermal energy neon atoms from a lithium overlayer on a copper substrate switches between a classical regime, dominated by multiphonon interactions, and a quantum regime, dominated by elastic diffraction. The transition is achieved by simple tailoring of the lithium coverage and quantum scattering dominates only in the narrow coverage range of theta=0.3-0.6 ML. The results are described qualitatively using a modified Debye-Waller model that incorporates an approximate quantum treatment of the adsorbate-substrate vibration.

  6. Unusual under-threshold ionization of neon clusters studied by ion spectroscopy

    NASA Astrophysics Data System (ADS)

    Nagaya, K.; Sugishima, A.; Iwayama, H.; Murakami, H.; Yao, M.; Fukuzawa, H.; Liu, X.-J.; Motomura, K.; Ueda, K.; Saito, N.; Foucar, L.; Rudenko, A.; Kurka, M.; Kühnel, K.-U.; Ullrich, J.; Czasch, A.; Dörner, R.; Feifel, R.; Nagasono, M.; Higashiya, A.; Yabashi, M.; Ishikawa, T.; Togashi, T.; Kimura, H.; Ohashi, H.

    2013-08-01

    We carried out time-of-flight mass spectrometry for neon clusters that were exposed to intense free electron laser pulses with the wavelength of 62 nm, which induce optical transition from the ground state (2s2 2p6) to an excited state (2s2 2p5 nl ) in the Ne atoms. In contrast to Ne+ ions produced by two-photon absorption from isolated Ne atoms, the Ne+ ion yield from Ne clusters shows a linear dependence on the laser intensity (I). We discuss the ionization mechanisms which give the linear behaviour with respect to I and expected features in the electron emission spectrum.

  7. RADIATION CHEMISTRY OF HIGH ENERGY CARBON, NEON AND ARGON IONS: INTEGRAL YIELDS FROM FERROUS SULFATE SOLUTIONS

    SciTech Connect

    Christman, E.A.; Appleby, A.; Jayko, M.

    1980-07-01

    Chemical yields of Fe{sup 3+} have been measured from FeSO{sub 4} solutions irradiated in the presence and absence of oxygen with carbon, neon, and argon ions from the Berkeley Bevalac facility. G(Fe{sup 3+}) decreases with increasing beam penetration and with increasing atomic number of the incident ion. The results are compared with current theoretical expectations of the behavior of these particles in an aqueous absorber. The chemical yields are consistently higher than theoretically predicted, by amounts varying from <6.2% (carbon ions) to <13.2% (argon ions). The additional yields are possibly attributable to fragmentation of the primary particle beams.

  8. Application of gas chromatographic method in simultaneous measurements of helium, argon and neon concentration in groundwaters

    NASA Astrophysics Data System (ADS)

    Najman, J.; Bielewski, J.; Sliwka, I.

    2012-04-01

    Helium concentration in groundwater is a fine indicator in water dating in a range from a hundred to tens of thousands of years. Gas chromatography (GC) measurements of helium can be used as an alternative to mass spectrometry (MS) determinations of 4He for groundwater dating [1]. Argon and neon concentrations mainly serve for determining the temperature of recharge and the air excess which is needed to correct measured values of helium concentration [2] . A chromatographic measurement system of helium, argon and neon concentration in groundwater is presented [3]. Water samples are taken from groundwater with a precise procedure without contamination with air in a special stainless steel vessels of volume equal to 2900 cm3. Helium is extracted from water samples using the head-space method. After enrichment by cryotrap method helium is analyzed in the gas chromatograph equipped with the thermal conductivity detector (TCD) with detection limit of about 2.8 ng He. The helium limit of detection of presented method is 1,2·10-8 cm3STP/gH2O [4]. We are currently working on adapting the method of cryogenic enrichment of helium concentration for simultaneous measurements of the concentration of helium, argon and neon using single sample of groundwater. Neon will be measured with the thermal conductivity detector and capillary column filled with molecular sieve 5A. Argon will be analyzed also with the thermal conductivity detector and packed column filled with molecular sieve 5A. This work was supported by grant No. N N525 3488 38 from the polish National Science Centre. [1] A. Zuber, W. Ciężkowski, K. Różański (red.), Tracer methods in hydrogeological studies - a methodological guide. Wroclaw University of Technology Publishing House, Wroclaw, 2007 (in polish). [2] P. Mochalski, Chromatographic method for the determination of Ar, Ne and N2 in water, Ph.D. thesis, Institute of Nuclear Physics Polish Academy of Sciences in Krakow, 2003 (in polish). [3] A. Żurek, P

  9. Structural transformations and melting in neon clusters: quantum versus classical mechanics.

    PubMed

    Frantsuzov, Pavel A; Meluzzi, Dario; Mandelshtam, Vladimir A

    2006-03-24

    The extraordinary complexity of Lennard-Jones (LJ) clusters, which exhibit numerous structures and "phases" when their size or temperature is varied, presents a great challenge for accurate numerical simulations, even without accounting for quantum effects. To study the latter, we utilize the variational Gaussian wave packet method in conjunction with the exchange Monte Carlo sampling technique. We show that the quantum nature of neon clusters has a substantial effect on their size-temperature "phase diagrams," particularly the critical parameters of certain structural transformations. We also give a numerical confirmation that none of the nonicosahedral structures observed for some classical LJ clusters are favorable in the quantum case.

  10. Formation of the structures from dusty clusters in neon dc discharge under cooling

    NASA Astrophysics Data System (ADS)

    Polyakov, D. N.; Shumova, V. V.; Vasilyak, L. M.

    2016-11-01

    The formation of structures consisted of dusty clusters in plasma at the discharge tube cooling to a temperature of liquid nitrogen was discovered. The dependence of the reduced electric field in the positive column of a discharge on gas temperature was experimentally measured. Depending on the pressure of neon were observed the different structural transitions in the regions of growing current-voltage characteristics at low discharge currents ≤ 1 mA. It was found that the regions of existence of structured clusters and the regions of structural transitions were characterized by the higher values of the reduced electric field than the regions of destruction of ordered structures.

  11. Delocalization of a Vacancy across Two Neon Atoms Bound by the van der Waals Force.

    PubMed

    Sann, H; Schober, C; Mhamdi, A; Trinter, F; Müller, C; Semenov, S K; Stener, M; Waitz, M; Bauer, T; Wallauer, R; Goihl, C; Titze, J; Afaneh, F; Schmidt, L Ph H; Kunitski, M; Schmidt-Böcking, H; Demekhin, Ph V; Cherepkov, N A; Schöffler, M S; Jahnke, T; Dörner, R

    2016-12-23

    We experimentally study 2p photoionization of neon dimers (Ne_{2}) at a photon energy of hν=36.56  eV. By postselection of ionization events which lead to a dissociation into Ne^{+}+Ne we obtain the photoelectron angular emission distribution in the molecular frame. This distribution is symmetric with respect to the direction of the charged vs neutral fragment. It shows an inverted Cohen-Fano double slit interference pattern of two spherical waves emitted coherently but with opposite phases from the two atoms of the dimer.

  12. Another neon nova - Early infrared photometry and spectroscopy of Nova Cygni 1992

    NASA Technical Reports Server (NTRS)

    Hayward, T. L.; Gehrz, R. D.; Miles, J. W.; Houck, J. R.

    1992-01-01

    Infrared photometry and spectrophotometry of Nova Cygni 1992 taken within 54 days of its eruption show a strong 12.8-micron Ne II forbidden emission line as well as hydrogen recombination lines. Spectra with lambda/Delta lambda of about 2000 resolve the Ne II forbidden and 12.37-micron Hu-alpha lines with about 2200 km/s (FWHM). The Ne II forbidden line shows multiple velocity components. The amount of forbidden Ne II required to produce the observed emission feature exceeds the solar abundance of neon by at least a factor of 4.

  13. The isotopic composition of neon and magnesium in the low energy cosmic rays

    NASA Technical Reports Server (NTRS)

    Garcia-Munoz, M.; Simpson, J. A.; Wefel, J. P.

    1980-01-01

    The ratios Ne-22/Ne-20 and Mg-26/Mg-24 were measured in galactic cosmic rays by the IMP-7 satellite in the 60 to 230 MeV/nucleon range. The neon cosmic ray source ratio Ne-22/Ne-20 is about 0.38, which is much larger than the current solar system relationship; the Mg data agrees with the solar system isotopic ratio of 0.14 at the cosmic ray source. The Ne and Mg source ratios are explained by supernova models, and become a new constraint which should be satisfied by any model of cosmic ray origin.

  14. Correlation energy and dispersion interaction in the ab initio potential energy curve of the neon dimer.

    PubMed

    Bytautas, Laimutis; Ruedenberg, Klaus

    2008-06-07

    A close approximation to the empirical potential energy curve of the neon dimer is obtained by coupled-cluster singles plus doubles plus noniterative triples calculations by using nonaugmented correlation-consistent basis sets without counterpoise corrections and complementing them by three-term extrapolations to the complete basis set limit. The potential energy is resolved into a self-consistent-field Hartree-Fock contribution and a correlation contribution. The latter is shown to decay in the long-range region in accordance with the empirical dispersion expansion.

  15. Dark-induced cone outer segment damage in the neon tetra (Paracheirodon innesi).

    PubMed

    Lythgoe, J N; Shand, J

    1984-11-01

    The outer segment of the twin cones of the neon tetra show scrolling and vesiculation when exposed to 36 hr of continuous darkness. This disruption first begins as a rolling of the margins of the cone lamellae and proceeds to form a complex pattern of scrolls and vesicles. There is evidence that this damage can be repaired without having to return the animals to a normal light regime. Similar lamellar disruptions have been seen in the outer segments of both rods and cones of other species that have been exposed to various other light regimes including constant light.

  16. Double ionization of neon by electron impact: use of correlated wave functions*

    NASA Astrophysics Data System (ADS)

    Kada, Imene; Cappello, Claude Dal; Mansouri, Abdelaziz

    2017-02-01

    A model including correlation both in the initial state and in the final state is applied to the case of the double ionization of neon. The results of our model are compared to the available experimental data performed at high incident energy. Fully (fivefold) differential cross sections (FDCS) have been studied by applying the first Born approximation. Four ion states of Ne++, which are not resolved in the experiments, have been included in our calculation. Contribution to the Topical Issue "Many Particle Spectroscopy of Atoms, Molecules, Clusters and Surfaces", edited by A.N. Grum-Grzhimailo, E.V. Gryzlova, Yu V. Popov, and A.V. Solov'yov.

  17. Delocalization of a Vacancy across Two Neon Atoms Bound by the van der Waals Force

    NASA Astrophysics Data System (ADS)

    Sann, H.; Schober, C.; Mhamdi, A.; Trinter, F.; Müller, C.; Semenov, S. K.; Stener, M.; Waitz, M.; Bauer, T.; Wallauer, R.; Goihl, C.; Titze, J.; Afaneh, F.; Schmidt, L. Ph. H.; Kunitski, M.; Schmidt-Böcking, H.; Demekhin, Ph. V.; Cherepkov, N. A.; Schöffler, M. S.; Jahnke, T.; Dörner, R.

    2016-12-01

    We experimentally study 2 p photoionization of neon dimers (Ne2 ) at a photon energy of h ν =36.56 eV . By postselection of ionization events which lead to a dissociation into Ne++Ne we obtain the photoelectron angular emission distribution in the molecular frame. This distribution is symmetric with respect to the direction of the charged vs neutral fragment. It shows an inverted Cohen-Fano double slit interference pattern of two spherical waves emitted coherently but with opposite phases from the two atoms of the dimer.

  18. Generation of electron beams from a laser wakefield acceleration in pure neon gas

    SciTech Connect

    Li, Song; Hafz, Nasr A. M. Mirzaie, Mohammad; Elsied, Ahmed M. M.; Ge, Xulei; Liu, Feng; Sokollik, Thomas; Chen, Min; Sheng, Zhengming; Zhang, Jie; Tao, Mengze; Chen, Liming

    2014-08-15

    We report on the generation of quasimonoenergetic electron beams by the laser wakefield acceleration of 17–50 TW, 30 fs laser pulses in pure neon gas jet. The generated beams have energies in the range 40–120 MeV and up to ∼430 pC of charge. At a relatively high density, we observed multiple electron beamlets which has been interpreted by simulations to be the result of breakup of the laser pulse into multiple filaments in the plasma. Each filament drives its own wakefield and generates its own electron beamlet.

  19. Normal Auger processes with ultrashort x-ray pulses in neon

    NASA Astrophysics Data System (ADS)

    Sullivan, Raymond; Jia, Junteng; Vázquez-Mayagoitia, Álvaro; Picón, Antonio

    2016-10-01

    Modern x-ray sources enable the production of coherent x-ray pulses with a pulse duration in the same order as the characteristic lifetimes of core-hole states of atoms and molecules. These pulses enable the manipulation of the core-hole population during Auger-decay processes, modifying the line shape of the electron spectra. In this work, we present a theoretical model to study those effects in neon. We identify effects in the Auger-electron-photoelectron coincidence spectrum due to the duration and intensity of the pulses. The normal Auger line shape is recovered in Auger-electron spectra integrated over all photoelectron energies.

  20. Optical excitation and decay dynamics of ytterbium atoms embedded in a solid neon matrix.

    SciTech Connect

    Xu, C.-Y.; Hu, S.-M.; Singh, J.; Bailey, K.; Lu, Z.-T.; Mueller, P.; O'Connor, T. P.; Welp, U.

    2011-09-01

    Neutral ytterbium atoms embedded in solid neon qualitatively retain the structure of free atoms. Despite the atom-solid interaction, the 6s6p {sup 3}P{sub 0} level is found to remain metastable with its lifetimes determined to be in the range of ten to hundreds of seconds. The atomic population can be almost completely transferred between the ground level and the metastable level via optical excitation and spontaneous decay. The dynamics of this process is examined and is used to explicitly demonstrate that the transition broadening mechanism is homogeneous.

  1. Optical Excitation and Decay Dynamics of Ytterbium Atoms Embedded in a Solid Neon Matrix

    SciTech Connect

    Xu, C.-Y.; Lu, Z.-T.; Hu, S.-M.; Singh, J.; Bailey, K.; Mueller, P.; O'Connor, T. P.; Welp, U.

    2011-08-26

    Neutral ytterbium atoms embedded in solid neon qualitatively retain the structure of free atoms. Despite the atom-solid interaction, the 6s6p {sup 3}P{sub 0} level is found to remain metastable with its lifetimes determined to be in the range of ten to hundreds of seconds. The atomic population can be almost completely transferred between the ground level and the metastable level via optical excitation and spontaneous decay. The dynamics of this process is examined and is used to explicitly demonstrate that the transition broadening mechanism is homogeneous.

  2. Vacuum-ultraviolet photolysis of H 3CF in solid neon: Infrared spectra of HCF and CF +

    NASA Astrophysics Data System (ADS)

    Wu, Yu-Jong; Chen, Hui-Fen; Chou, Sheng-Lung; Lin, Meng-Yeh; Cheng, Bing-Ming

    2010-09-01

    Irradiation of a sample containing fluoromethane dispersed in solid neon near 3.0 K with light from a synchrotron at wavelength 124 nm generated products that were detected with infrared absorption spectra. The identified products include CF, CF+, CF2, HCF, H2CF, C2F2, C2F2H2, CH3, CH, C2H2 and HF. Isotopic labeling with 13C and deuterium and quantum-chemical calculations confirmed the identification of these species; the vibrational spectra of CF+ and HCF (CH stretching mode) are recorded for the first time in solid neon.

  3. Electrical and optical characteristics of atmospheric pressure plasma needle jet driven by neon trasformer

    NASA Astrophysics Data System (ADS)

    Elfa, Rizan Rizon; Ahmad, Mohd Khairul; Soon, Chin Fhong; Sahdan, Mohd Zainizan; Lias, Jais; Mamat, Mohamad Hafiz; Rusop, Mohamad; Nayan, Nafarizal

    2017-09-01

    The atmospheric pressure plasma needle jet driven by double sinusoidal waveform of neon transformer is reported in this paper. The commercial neon transformer produces about 5 kV of peak sinusoidal voltages and 35 kHz of frequency. Argon gas has been used as discharge gas for this system since the discharge was easily developed rather than using helium gas. In addition, argon gas is three times cheaper than helium gas. The electrical property of the argon discharge has been analyzed in details by measuring its voltage, current and power during the discharge process. Interestingly, it has been found that the total power on the inner needle electrode was slightly lower than that of outer electrode. This may be due to the polarization charges that occurred at inner needle electrode. Then, further investigation to understand the discharge properties was carried out using optical emission spectroscopy (OES) analysis. During OES measurements, two positions of plasma discharge are measured by aligning the quartz optical lens and spectrometer fiber. The OH emission intensity was found higher than that of N2 at the plasma orifice. However, OH emission intensity was lower at 1.5 cm distance from orifice which may be due to penning ionization effect. These results and understanding are essential for surface modification and biomedical applications of atmospheric pressure plasma needle jet.

  4. First principles study of inert-gas (helium, neon, and argon) interactions with hydrogen in tungsten

    NASA Astrophysics Data System (ADS)

    Kong, Xiang-Shan; Hou, Jie; Li, Xiang-Yan; Wu, Xuebang; Liu, C. S.; Chen, Jun-Ling; Luo, G.-N.

    2017-04-01

    We have systematically evaluated binding energies of hydrogen with inert-gas (helium, neon, and argon) defects, including interstitial clusters and vacancy-inert-gas complexes, and their stable configurations using first-principles calculations. Our calculations show that these inert-gas defects have large positive binding energies with hydrogen, 0.4-1.1 eV, 0.7-1.0 eV, and 0.6-0.8 eV for helium, neon, and argon, respectively. This indicates that these inert-gas defects can act as traps for hydrogen in tungsten, and impede or interrupt the diffusion of hydrogen in tungsten, which supports the discussion on the influence of inert-gas on hydrogen retention in recent experimental literature. The interaction between these inert-gas defects and hydrogen can be understood by the attractive interaction due to the distortion of the lattice structure induced by inert-gas defects, the intrinsic repulsive interaction between inert-gas atoms and hydrogen, and the hydrogen-hydrogen repelling in tungsten lattice.

  5. Joule-Thomson cryocooler with neon and nitrogen mixture using commercial air-conditioning compressors

    NASA Astrophysics Data System (ADS)

    Lee, Jisung; Oh, Haejin; Baek, Seungwhan; Lee, Cheonkyu; Jeong, Sangkwon

    2014-01-01

    A 2-stage mixed refrigerant (MR) Joule-Thomson (JT) cryocooler was designed for cooling high temperature superconducting cable below 70 K. The low temperature cycle was to operate with neon-nitrogen mixture, and the required compression ratio was approximately 24 when the suction pressure was 100 kPa. The high compression ratio of 24, the low pressure of 100 kPa at compressor suction, and the working fluid with high heat of compression were challenging issues to existing typical compression systems. We developed an innovative compression system with commercial oil-lubricated air-conditioning compressors. They were 2-stage rotary compressors originally designed for R410Aand connected in series. The compressors were modified to accommodate effective intercooling at every stage to alleviate compressor overheating problem. Additionally, fine-grade three-stage oil filters, an adsorber, and driers were installed at the discharge line to avoid a potential clogging problem from oil mist and moisture at low temperature sections. The present compression system was specifically demonstrated with a neon-nitrogen MR JT cryocooler. The operating pressure ratio was able to meet the designed specifications, and the recorded no-load mini mum temperature was 63.5 K . Commercial air-conditioning compressors were successfully applied to the high-c ompression ratio MR JT cryocooler with adequate modification using off-the-shelf components.

  6. Mechanism of variable structural colour in the neon tetra: quantitative evaluation of the Venetian blind model

    PubMed Central

    Yoshioka, S.; Matsuhana, B.; Tanaka, S.; Inouye, Y.; Oshima, N.; Kinoshita, S.

    2011-01-01

    The structural colour of the neon tetra is distinguishable from those of, e.g., butterfly wings and bird feathers, because it can change in response to the light intensity of the surrounding environment. This fact clearly indicates the variability of the colour-producing microstructures. It has been known that an iridophore of the neon tetra contains a few stacks of periodically arranged light-reflecting platelets, which can cause multilayer optical interference phenomena. As a mechanism of the colour variability, the Venetian blind model has been proposed, in which the light-reflecting platelets are assumed to be tilted during colour change, resulting in a variation in the spacing between the platelets. In order to quantitatively evaluate the validity of this model, we have performed a detailed optical study of a single stack of platelets inside an iridophore. In particular, we have prepared a new optical system that can simultaneously measure both the spectrum and direction of the reflected light, which are expected to be closely related to each other in the Venetian blind model. The experimental results and detailed analysis are found to quantitatively verify the model. PMID:20554565

  7. First-principles study of conducting behavior of warm dense neon

    NASA Astrophysics Data System (ADS)

    Tang, J.; Chen, Q. F.; Fu, Z. J.; Li, Z. G.; Quan, W. L.; Gu, Y. J.; Zheng, J.

    2017-08-01

    The energy gap of solid neon increases with density, which is an opposite density dependency compared to other noble gases. In order to investigate whether this abnormal phenomenon survives in the warm dense region, where the conducting behavior is closely related to the energy gap, we calculated the electrical conductivity of fluid neon for temperatures of 103-105 K and densities of 1.50-10.0 g/cm3 with a first-principles method. Temperature and density dependencies of conductivity in this region were analyzed. The results indicate that the conducting behavior is sensitive to the temperature; there is a significant increase in the direct current (dc) conductivity from 10 000 to 20 000 K. Contrary to other noble gases, we found an abnormal density dependency of dc conductivity, which decreases with increasing density at a given temperature. This phenomenon is due to the elevating localization of electrons and the broadening of the energy gap based on the analyses of charge density distribution and electronic structure under these extreme conditions. Finally, an insulating-conducting fluid phase diagram was constructed using our simulation results, which confirmed the conclusion of the latest experiment results.

  8. Abundance ratios of oxygen, neon, and magnesium in solar active regions and flares: The FIP effect

    NASA Technical Reports Server (NTRS)

    Widing, K. G.; Feldman, U.

    1995-01-01

    Relative abundances of oxygen, neon, and magnesium have been derived for a sample of nine solar active regions, flares, and an erupting prominance by combining plots of the ion differential emission measures. The observations were photographed in the 300-600 A range by the Naval Research Laboratory (NRL) spectroheliograph on Skylab. Methods for deriving the Mg/Ne abundance ratio-which measures the separation between the low- first ionization potential (FIP) and high-FIP abundnace plateaus-have been described in previous papers. In this paper we describe the spectroscopic methods for deriving the O/Ne abundance ratio, which gives the ratio between two high-FIP elements. The plot of the O/Ne ratio versus the Mg/Ne ratio in the sample of nine Skylab events is shown. The variation in the Mg/Ne ratio by a factor of 6 is associated with a much smaller range in the O/Ne ratio. This is broadly consistent with the presence of the standard FIP pattern of abundances in the outer atmosphere of the Sun. However, a real change in the relative abundances of oxygen and neon by a factor of 1.5 cannot be excluded.

  9. Analysis of trace impurities in neon by a customized gas chromatography.

    PubMed

    Yin, Min Kyo; Lim, Jeong Sik; Moon, Dong Min; Lee, Gae Ho; Lee, Jeongsoon

    2016-09-09

    Excimer lasers, widely used in the semiconductor industry, are crucial for analyzing the purity of premix laser gases for the purpose of controlling stable laser output power. In this study, we designed a system for analyzing impurities in pure neon (Ne) base gas by customized GC. Impurities in pure neon (H2 and He), which cannot be analyzed at the sub-μmol/mol level using commercial GC detectors, were analyzed by a customized pulsed-discharge Ne ionization detector (PDNeD) and a pressurized injection thermal conductivity detector using Ne as the carrier gas (Pres. Inj. Ne-TCD). From the results, trace species in Ne were identified with the following detection limits: H2, 0.378μmol/mol; O2, 0.119μmol/mol; CH4, 0.880μmol/mol; CO, 0.263μmol/mol; CO2, 0.162μmol/mol (PDNeD); and He, 0.190μmol/mol (Pres. Inj. Ne-TCD). This PDNeD and pressurized injection Ne-TCD technique thus developed permit the quantification of trace impurities present in high-purity Ne. Copyright © 2016. Published by Elsevier B.V.

  10. Charge state of anomalous cosmic-ray nitrogen, oxygen, and neon: SAMPEX observations

    NASA Technical Reports Server (NTRS)

    Klecker, B.; Mcnab, M. C.; Blake, J. B.; Hamilton, D. C.; Hovestadt, D.; Kaestle, H.; Looper, M. D.; Mason, G. M.; Mazur, J. E.; Scholer, M.

    1995-01-01

    We report observations of the ionization state of anomalous cosmic-ray (ACR) nitrogen, oxygen, and neon during the period 1992 October to 1993 May, carried out with instrumentation on the Solar, Anomalous & Magnetospheric Particle Explorer (SAMPEX) spacecraft. The low-altitude (510 x 675 km) and high-inclination (82 deg) orbit enables SAMPEX to sample the interplanetary ACR fluxes on each polar pass and then to observe the cutoff of these fluxes by the geomagnetic field at lower latitudes. The arrival time and direction of each ion is recorded by the instruments, allowing detailed calculations of the particle's trajectory through the Earth's magnetic field and thereby placing upper limits on the ionization state of the particles. We find (a) that ACR nitrogen, oxygen, and neon each contain singly ionized particles and (b) that ACR oxygen is predominantly singly ionized with an upper limit of 10% for higher ionization states. These ionization states confirm theories of ACR origin as neutral interstellar material that is singly ionized near the Sun by UV or charge exchange with the solar wind, and is subsequently accelerated in the outer heliosphere.

  11. Control of coherent excitation of neon in the extreme ultraviolet regime.

    PubMed

    Plenge, Jürgen; Wirsing, Andreas; Raschpichler, Christopher; Wassermann, Bernhard; Rühl, Eckart

    2011-01-01

    Coherent excitation of a superposition of Rydberg states in neon by the 13th harmonic of an intense 804 nm pulse and the formation of a wave packet is reported. Pump-probe experiments are performed, where the 3d-manifold of the 2p6-->2p5 (2P3/2) 3d [1/2]1- and 2p6-->2p5 (2P3/2) 3d [3/2]1-transitions are excited by an extreme ultraviolet (XUV) radiation pulse, which is centered at 20.05 eV photon energy. The temporal evolution of the excited state population is probed by ionization with a time-delayed 804 nm pulse. Control of coherent transient excitation and wave packet dynamics in the XUV-regime is demonstrated, where the spectral phase of the 13th harmonic is used as a control parameter. Modulation of the phase is achieved by propagation of the XUV-pulse through neon of variable gas density. The experimental results indicate that phase-shaped high-order harmonics can be used to control fundamental coherent excitation processes in the XUV-regime.

  12. Double deuterated acetylacetone in neon matrices: infrared spectroscopy, photoreactivity and the tunneling process.

    PubMed

    Gutiérrez-Quintanilla, Alejandro; Chevalier, Michèle; Crépin, Claudine

    2016-07-27

    The effect of deuteration of acetylacetone (C5O2H8) is explored by means of IR spectroscopy of its single and double deuterated isotopologues trapped in neon matrices. The whole vibrational spectra of chelated enols are very sensitive to the H-D exchange of the hydrogen atom involved in the internal hydrogen bond. UV excitation of double deuterated acetylacetone isolated in neon matrices induces the formation of four open enol isomers which can be divided into two groups of two conformers, depending on their formation kinetics. Within each group, one conformer is more stable than the other: slow conformer interconversion due to a tunneling process is observed in the dark at low temperature. Moreover, IR laser irradiation at the OD stretching overtone frequency is used to induce interconversion either from the most stable to the less stable conformer or the opposite, depending on the excitation wavelength. The interconversion process is of great help to assign conformers which are definitively identified by comparison between experimental and calculated IR spectra. Kinetic constants of the tunneling process at play are theoretically estimated and agree perfectly with experiments, including previous experiments with the totally hydrogenated acetylacetone [Lozada García et al., Phys. Chem. Chem. Phys., 2012, 14, 3450].

  13. Experimental evidence of chemical components in the bonding of helium and neon with neutral molecules.

    PubMed

    Cappelletti, David; Bartocci, Alessio; Grandinetti, Felice; Falcinelli, Stefano; Belpassi, Leonardo; Tarantelli, Francesco; Pirani, Fernando

    2015-04-13

    The complexes of helium and neon with gaseous neutral molecules are generally perceived to be van der Waals adducts held together by physical (non-covalent) forces, owing to the combination of size (exchange) repulsion with dispersion/induction attraction. Molecular beam experiments confirm that this is the case for He-CF4 , Ne-CF4 adducts, but revealed that the interaction of He and Ne with CCl4 features an appreciable contribution of chemical components that arise from the anisotropy of the electron density of CCl4 that enhances a charge transfer from Ng (Ng=He, Ne). These findings furnish a novel assay of the bonding capabilities of helium and neon, and invite to revisit the neutral complexes of these elements as systems of chemical relevance. The CCl4 -Ng are also peculiar examples of halogen bonds, a group of interactions of major current concern. Finally, this investigation is a prelude to the development of semi-empirical models for force fields aimed to the unified description of static and dynamical properties of systems of comparable or higher complexity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Optical absorption of small copper clusters in neon: Cu(n), (n = 1-9).

    PubMed

    Lecoultre, S; Rydlo, A; Félix, C; Buttet, J; Gilb, S; Harbich, W

    2011-02-21

    We present optical absorption spectra in the UV-visible range (1.6 eV < ℏω < 5.5 eV) of mass selected neutral copper clusters Cu(n)(n = 1-9) embedded in a solid neon matrix at 7 K. The atom and the dimer have already been measured in neon matrices, while the absorption spectra for sizes between Cu(3) and Cu(9) are entirely (n = 6-9) or in great part new. They show a higher complexity and a larger number of transitions distributed over the whole energy range compared to similar sizes of silver clusters. The experimental spectra are compared to the time dependent density functional theory (TD-DFT) implemented in the TURBOMOLE package. The analysis indicates that for energies larger than 3 eV the transitions are mainly issued from d-type states; however, the TD-DFT scheme does not reproduce well the detailed structure of the absorption spectra. Below 3 eV the agreement for transitions issued from s-type states is better.

  15. Mechanism of variable structural colour in the neon tetra: quantitative evaluation of the Venetian blind model.

    PubMed

    Yoshioka, S; Matsuhana, B; Tanaka, S; Inouye, Y; Oshima, N; Kinoshita, S

    2011-01-06

    The structural colour of the neon tetra is distinguishable from those of, e.g., butterfly wings and bird feathers, because it can change in response to the light intensity of the surrounding environment. This fact clearly indicates the variability of the colour-producing microstructures. It has been known that an iridophore of the neon tetra contains a few stacks of periodically arranged light-reflecting platelets, which can cause multilayer optical interference phenomena. As a mechanism of the colour variability, the Venetian blind model has been proposed, in which the light-reflecting platelets are assumed to be tilted during colour change, resulting in a variation in the spacing between the platelets. In order to quantitatively evaluate the validity of this model, we have performed a detailed optical study of a single stack of platelets inside an iridophore. In particular, we have prepared a new optical system that can simultaneously measure both the spectrum and direction of the reflected light, which are expected to be closely related to each other in the Venetian blind model. The experimental results and detailed analysis are found to quantitatively verify the model.

  16. The solar wind neon abundance observed with ACE/SWICS and ULYSSES/SWICS

    SciTech Connect

    Shearer, Paul; Raines, Jim M.; Lepri, Susan T.; Thomas, Jonathan W.; Gilbert, Jason A.; Landi, Enrico; Zurbuchen, Thomas H.; Von Steiger, Rudolf

    2014-07-01

    Using in situ ion spectrometry data from ACE/SWICS, we determine the solar wind Ne/O elemental abundance ratio and examine its dependence on wind speed and evolution with the solar cycle. We find that Ne/O is inversely correlated with wind speed, is nearly constant in the fast wind, and correlates strongly with solar activity in the slow wind. In fast wind streams with speeds above 600 km s{sup –1}, we find Ne/O = 0.10 ± 0.02, in good agreement with the extensive polar observations by Ulysses/SWICS. In slow wind streams with speeds below 400 km s{sup –1}, Ne/O ranges from a low of 0.12 ± 0.02 at solar maximum to a high of 0.17 ± 0.03 at solar minimum. These measurements place new and significant empirical constraints on the fractionation mechanisms governing solar wind composition and have implications for the coronal and photospheric abundances of neon and oxygen. The results are made possible by a new data analysis method that robustly identifies rare elements in the measured ion spectra. The method is also applied to Ulysses/SWICS data, which confirms the ACE observations and extends our view of solar wind neon into the three-dimensional heliosphere.

  17. Sub-cooled liquid nitrogen cryogenic system with neon turbo-refrigerator for HTS power equipment

    NASA Astrophysics Data System (ADS)

    Yoshida, S.; Hirai, H.; Nara, N.; Ozaki, S.; Hirokawa, M.; Eguchi, T.; Hayashi, H.; Iwakuma, M.; Shiohara, Y.

    2014-01-01

    We developed a prototype sub-cooled liquid nitrogen (LN) circulation system for HTS power equipment. The system consists of a neon turbo-Brayton refrigerator with a LN sub-cooler and LN circulation pump unit. The neon refrigerator has more than 2 kW cooling power at 65 K. The LN sub-cooler is a plate-fin type heat exchanger and is installed in a refrigerator cold box. In order to carry out the system performance tests, a dummy cryostat having an electric heater was set instead of a HTS power equipment. Sub-cooled LN is delivered into the sub-cooler by the LN circulation pump and cooled within it. After the sub-cooler, sub-cooled LN goes out from the cold box to the dummy cryostat, and comes back to the pump unit. The system can control an outlet sub-cooled LN temperature by adjusting refrigerator cooling power. The refrigerator cooling power is automatically controlled by the turbo-compressor rotational speed. In the performance tests, we increased an electric heater power from 200 W to 1300 W abruptly. We confirmed the temperature fluctuation was about ±1 K. We show the cryogenic system details and performance test results in this paper.

  18. Triple point temperature of neon isotopes: Dependence on nitrogen impurity and sealed-cell model

    SciTech Connect

    Pavese, F.; Steur, P. P. M.; Giraudi, D.

    2013-09-11

    This paper illustrates a study conducted at INRIM, to further check how some quantities influence the value of the triple point temperature of the neon high-purity isotopes {sup 20}Ne and {sup 22}Ne. The influence of nitrogen as a chemical impurity in neon is critical with regard to the present best total uncertainty achieved in the measurement of these triple points, but only one determination is available in the literature. Checks are reported, performed on two different samples of {sup 22}Ne known to contain a N{sub 2} amount of 157⋅10{sup −6}, using two different models of sealed cells. The model of the cell can, in principle, have some effects on the shape of the melting plateau or on the triple point temperature observed for the sample sealed in it. This can be due to cell thermal parameters, or because the INRIM cell element mod. c contains many copper wires closely packed, which can, in principle, constrain the interface and induce a premelting-like effect. The reported results on a cell mod. Bter show no evident effect from the cell model and provide a value for the effect of N{sub 2} in Ne liquidus point of 8.6(1.9) μK ppm N{sub 2}{sup −1}, only slightly different from the literature datum.

  19. Inclusive Neutron Production by 790 Mev/nucleon Neon Ions on Lead and Sodium Fluoride

    NASA Astrophysics Data System (ADS)

    Baldwin, Alan Richard

    The inclusive double-differential cross sections for neutron production were measured at angles of 0, 15, 30, 50, 70, 90, 120, and 160 degrees. The neutrons were produced by 790 MeV/nucleon Neon ions bombarding targets of Pb and NaF. A striking peak in the zero degree spectra at a neutron energy slightly below the beam energy per nucleon is suggested to be particle evaporation superimposed on the broader fragmentation process predicted by statistical models. The Lorentz-invariant cross section at 0 degrees in the rest frame of the projectile are interpreted to include three processes of neutron emission: (1) the excitation and evaporative decay of the projectile spectator provides an estimate for the temperature of 3.5 +/- 0.7 and 3.4 +/- 0.7 MeV/k for Ne-Pb and Ne-NaF collisions, (2) the fragmentation of a neutron from the projectile yielded a Fermi momentum of 295 +/- 22 and 259 +/- 22 MeV/c for the Neon ion in the Ne-Pb and Ne-NaF collisions respectively, and (3) the high-energy tail may be explained by backscattering of a neutron in the target from a cluster of nucleons in the projectile with an average cluster size of about 1.2 nucleons.

  20. Abundance ratios of oxygen, neon, and magnesium in solar active regions and flares: The FIP effect

    NASA Technical Reports Server (NTRS)

    Widing, K. G.; Feldman, U.

    1995-01-01

    Relative abundances of oxygen, neon, and magnesium have been derived for a sample of nine solar active regions, flares, and an erupting prominance by combining plots of the ion differential emission measures. The observations were photographed in the 300-600 A range by the Naval Research Laboratory (NRL) spectroheliograph on Skylab. Methods for deriving the Mg/Ne abundance ratio-which measures the separation between the low- first ionization potential (FIP) and high-FIP abundnace plateaus-have been described in previous papers. In this paper we describe the spectroscopic methods for deriving the O/Ne abundance ratio, which gives the ratio between two high-FIP elements. The plot of the O/Ne ratio versus the Mg/Ne ratio in the sample of nine Skylab events is shown. The variation in the Mg/Ne ratio by a factor of 6 is associated with a much smaller range in the O/Ne ratio. This is broadly consistent with the presence of the standard FIP pattern of abundances in the outer atmosphere of the Sun. However, a real change in the relative abundances of oxygen and neon by a factor of 1.5 cannot be excluded.

  1. Positive column of a glow discharge in neon with charged dust grains (a review)

    NASA Astrophysics Data System (ADS)

    Polyakov, D. N.; Shumova, V. V.; Vasilyak, L. M.

    2017-03-01

    The effect of charged micron-size dust grains (microparticles) on the electric parameters of the positive column of a low-pressure dc glow discharge in neon has been studied experimentally and numerically. Numerical analysis is carried out in the diffusion-drift approximation with allowance for the interaction of dust grains with metastable neon atoms. In a discharge with a dust grain cloud, the longitudinal electric field increases. As the number density of dust grains in an axisymmetric cylindrical dust cloud rises, the growth of the electric field saturates. It is shown that the contribution of metastable atoms to ionization is higher in a discharge with dust grains, in spite of the quenching of metastable atoms on dust grains. The processes of charging of dust grains and the dust cloud are considered. As the number density of dust grains rises, their charge decreases, while the space charge of the dust cloud increases. The results obtained can be used in plasma technologies involving microparticles.

  2. Two-photon double ionization of neon using an intense attosecond pulse train

    NASA Astrophysics Data System (ADS)

    Manschwetus, B.; Rading, L.; Campi, F.; Maclot, S.; Coudert-Alteirac, H.; Lahl, J.; Wikmark, H.; Rudawski, P.; Heyl, C. M.; Farkas, B.; Mohamed, T.; L'Huillier, A.; Johnsson, P.

    2016-06-01

    We present a demonstration of two-photon double ionization of neon using an intense extreme ultraviolet (XUV) attosecond pulse train (APT) in a photon energy regime where both direct and sequential mechanisms are allowed. For an APT generated through high-order harmonic generation (HHG) in argon we achieve a total pulse energy close to 1 μ J , a central energy of 35 eV, and a total bandwidth of ˜30 eV. The APT is focused by broadband optics in a neon gas target to an intensity of 3 ×1012W cm-2 . By tuning the photon energy across the threshold for the sequential process the double ionization signal can be turned on and off, indicating that the two-photon double ionization predominantly occurs through a sequential process. The demonstrated performance opens up possibilities for future XUV-XUV pump-probe experiments with attosecond temporal resolution in a photon energy range where it is possible to unravel the dynamics behind direct versus sequential double ionization and the associated electron correlation effects.

  3. Direct measurement of neon production rates by (α,n) reactions in minerals

    NASA Astrophysics Data System (ADS)

    Cox, Stephen E.; Farley, Kenneth A.; Cherniak, Daniele J.

    2015-01-01

    The production of nucleogenic neon from alpha particle capture by 18O and 19F offers a potential chronometer sensitive to temperatures higher than the more widely used (U-Th)/He chronometer. The accuracy depends on the cross sections and the calculated stopping power for alpha particles in the mineral being studied. Published 18O(α,n)21Ne production rates are in poor agreement and were calculated from contradictory cross sections, and therefore demand experimental verification. Similarly, the stopping powers for alpha particles are calculated from SRIM (Stopping Range of Ions in Matter software) based on a limited experimental dataset. To address these issues we used a particle accelerator to implant alpha particles at precisely known energies into slabs of synthetic quartz (SiO2) and barium tungstate (BaWO4) to measure 21Ne production from capture by 18O. Within experimental uncertainties the observed 21Ne production rates compare favorably to our predictions using published cross sections and stopping powers, indicating that ages calculated using these quantities are accurate at the ∼3% level. In addition, we measured the 22Ne/21Ne ratio and (U-Th)/He and (U-Th)/Ne ages of Durango fluorapatite, which is an important model system for this work because it contains both oxygen and fluorine. Finally, we present 21Ne/4He production rate ratios for a variety of minerals of geochemical interest along with software for calculating neon production rates and (U-Th)/Ne ages.

  4. Photoelectron angular distribution in two-pathway ionization of neon with femtosecond XUV pulses

    NASA Astrophysics Data System (ADS)

    Douguet, Nicolas; Gryzlova, Elena V.; Staroselskaya, Ekaterina I.; Bartschat, Klaus; Grum-Grzhimailo, Alexei N.

    2017-05-01

    We analyze the photoelectron angular distribution in two-pathway interference between nonresonant one-photon and resonant two-photon ionization of neon. We consider a bichromatic femtosecond XUV pulse whose fundamental frequency is tuned near the 2p53s atomic states of neon. The time-dependent Schrödinger equation is solved and the results are employed to compute the angular distribution and the associated anisotropy parameters at the main photoelectron line. We also employ a time-dependent perturbative approach, which allows obtaining information on the process for a large range of pulse parameters, including the steady-state case of continuous radiation, i.e., an infinitely long pulse. The results from the two methods are in relatively good agreement over the domain of applicability of perturbation theory. Contribution to the Topical Issue "Many Particle Spectroscopy of Atoms, Molecules, Clusters and Surfaces", edited by A.N. Grum-Grzhimailo, E.V. Gryzlova, Yu V. Popov, and A.V. Solov'yov.

  5. The solubility of neon, nitrogen and argon in distilled water and seawater

    NASA Astrophysics Data System (ADS)

    Hamme, Roberta C.; Emerson, Steven R.

    2004-11-01

    Large discrepancies in published neon and nitrogen solubility data limit the interpretation of oceanic measurements of these gases. We present new solubility measurements for neon, nitrogen and argon in distilled water and seawater, over a temperature range of 1- 30∘ C. Water was equilibrated with air at measured temperatures, salinities and pressures. Dissolved Ne concentrations were then determined by isotope dilution using a quadrupole mass spectrometer. Ratios of O2 /N2 / Ar were measured on a stable isotope ratio mass spectrometer, from which absolute N2 and Ar concentrations were calculated using published O2 solubilities. We propose new equations, fitted to the data, for the equilibrium concentrations of Ne, N2 and Ar with estimated errors of 0.30%, 0.14% and 0.13%, respectively. The Ar results matched those of most previous researchers within 0.4%. However, the Ne and N2 results were greater by 1% or more than those of Weiss (J. Chem. Eng. Data 16(2) (1971b) 235, Deep-Sea Res. 17(4) (1970) 721).

  6. Time delay between photoemission from the 2p and 2s subshells of neon

    SciTech Connect

    Moore, L. R.; Lysaght, M. A.; Parker, J. S.; Hart, H. W. van der; Taylor, K. T.

    2011-12-15

    The R-matrix incorporating time (RMT) method is a method developed recently for solving the time-dependent Schroedinger equation for multielectron atomic systems exposed to intense short-pulse laser light. We have employed the RMT method to investigate the time delay in the photoemission of an electron liberated from a 2p orbital in a neon atom with respect to one released from a 2s orbital following absorption of an attosecond xuv pulse. Time delays due to xuv pulses in the range 76-105 eV are presented. For an xuv pulse at the experimentally relevant energy of 105.2 eV, we calculate the time delay to be 10.2{+-}1.3 attoseconds (as), somewhat larger than estimated by other theoretical calculations, but still a factor of 2 smaller than experiment. We repeated the calculation for a photon energy of 89.8 eV with a larger basis set capable of modeling correlated-electron dynamics within the neon atom and the residual Ne{sup +} ion. A time delay of 14.5{+-}1.5 as was observed, compared to a 16.7{+-}1.5 as result using a single-configuration representation of the residual Ne{sup +} ion.

  7. Charge state of anomalous cosmic-ray nitrogen, oxygen, and neon: SAMPEX observations

    NASA Technical Reports Server (NTRS)

    Klecker, B.; Mcnab, M. C.; Blake, J. B.; Hamilton, D. C.; Hovestadt, D.; Kaestle, H.; Looper, M. D.; Mason, G. M.; Mazur, J. E.; Scholer, M.

    1995-01-01

    We report observations of the ionization state of anomalous cosmic-ray (ACR) nitrogen, oxygen, and neon during the period 1992 October to 1993 May, carried out with instrumentation on the Solar, Anomalous & Magnetospheric Particle Explorer (SAMPEX) spacecraft. The low-altitude (510 x 675 km) and high-inclination (82 deg) orbit enables SAMPEX to sample the interplanetary ACR fluxes on each polar pass and then to observe the cutoff of these fluxes by the geomagnetic field at lower latitudes. The arrival time and direction of each ion is recorded by the instruments, allowing detailed calculations of the particle's trajectory through the Earth's magnetic field and thereby placing upper limits on the ionization state of the particles. We find (a) that ACR nitrogen, oxygen, and neon each contain singly ionized particles and (b) that ACR oxygen is predominantly singly ionized with an upper limit of 10% for higher ionization states. These ionization states confirm theories of ACR origin as neutral interstellar material that is singly ionized near the Sun by UV or charge exchange with the solar wind, and is subsequently accelerated in the outer heliosphere.

  8. Experimental investigation on the performance of a neon cryogenic oscillating heat pipe

    NASA Astrophysics Data System (ADS)

    Liang, Qing; Li, Yi; Wang, Qiuliang

    2017-06-01

    An experimental investigation is conducted to study the performance of a cryogenic oscillating heat pipe (OHP) using neon as the working fluid. The stainless steel OHP with an inner diameter of 0.9 mm has 4 turns, and the lengths of the evaporator, condenser section and adiabatic section are 35 mm, 35 mm and 95 mm, respectively. The temperature of the evaporator and condenser and the pressure of the OHP are measured. The results show that the cooling down process of the OHP from room temperature to the working temperature can be significantly accelerated by charging with neon. During the pseudo steady-state operation process, the temperature of evaporator and the pressure of the OHP increase with increasing heat input. When the dry out appears, the temperature of evaporator rises quickly, and the pressure of the OHP drops sharply. In addition, the effective thermal conductivity of the OHP at the different heat inputs and the different filling ratios is calculated. It increases with increasing heat input, and there exists an optimum filling ratio which makes the maximum effective thermal conductivity. For this OHP, the optimum filling ratio is 24.5%, at which the effective thermal conductivity is 6100-22,180 W/m K.

  9. Utilizing Neon Ion Microscope for GaSb nanopatterning studies: Nanostructure formation and comparison with low energy nanopatterning

    NASA Astrophysics Data System (ADS)

    El-Atwani, Osman; Huynh, Chuong; Norris, Scott

    2016-05-01

    Low energy irradiation of GaSb surfaces has been shown to lead to nanopillar formation. Being performed ex-situ, controlling the parameters of the ion beam for controlled nanopattern formation is challenging. While mainly utilized for imaging and cutting purposes, the development of multibeam (helium/neon) ion microscopes has opened the path towards the use of these microscopes for in-situ ion irradiation and nanopatterning studies. In this study, in-situ irradiation (neon ions)/imaging (helium ions) of GaSb surfaces is performed using Carl Zeiss-neon ion microscope at low energies (5 and 10 keV). Imaging with helium ions, nanodots were shown to form at particular fluences after which are smoothed. Ex-situ imaging with SEM showed nanopore formation of size controlled by the ion energy and fluence. Compared to lower energy ex-situ neon ion irradiation at similar fluxes, where nanopillars are formed, the results demonstrated a transition in the nanostructure type and formation mechanism as the energy is changed from 2 to 5 keV. Simulations show an increase in the ballistic diffusion and a decrease in the strength of phase separation as a function of ion energy in agreement with the suppression of nanopillar formation at higher energies. Collision cascade simulations suggest a transition toward bulk-driven mechanisms.

  10. Auger and radiative deexcitation of the 1s2l3l prime configurations of lithium-like neon

    NASA Technical Reports Server (NTRS)

    Chen, M. H.

    1976-01-01

    The three-electron configurations of 1s2lambda3lambda of neon are observed in ion-atom collisions and beam foil excitation. Multiplet Auger and x ray transition rates obtained in intermediate coupling are calculated. Fluorescence yields are also computed.

  11. Electron spin resonance investigation of H2(+), HD(+), and D2(+) isolated in neon matrices at 2 K.

    PubMed

    Correnti, Matthew D; Dickert, Kyle P; Pittman, Mark A; Felmly, John W; Banisaukas, John J; Knight, Lon B

    2012-11-28

    Various isotopologues of nature's simplest molecule, namely H(2)(+), HD(+), and D(2)(+), have been isolated in neon matrices at 2 K for the first time and studied by electron spin resonance (ESR). Over many years, hundreds of matrix isolation experiments employing a variety of deposition conditions and ion generation methods have been tried to trap the H(2)(+) cation radical in our laboratory. The molecule has been well characterized in the gas phase and by theoretical methods. The observed magnetic parameters for H(2)(+) in neon at 2 K are: g(∥) ≈ g(⊥) = 2.0022(1); A(iso)(H) = 881(7) MHz; and A(dip)(H) = 33(3) MHz. Reasonable agreement with gas phase values of the isotropic hyperfine interaction (A(iso)) is observed; however, the neon matrix dipolar hyperfine interaction (A(dip)) is noticeably below the gas phase value. The smaller matrix value of A(dip) is attributable to motional averaging of the H(2)(+) radical in the neon matrix trapping site--an occurrence that would prevent the full extent of the hyperfine anisotropy from being measured for a powder pattern type ESR sample.

  12. Qualitative and quantitative difference in mutation induction between carbon- and neon-ion beams in normal human cells.

    PubMed

    Suzuki, Masao; Tsuruoka, Chizuru; Kanai, Tatsuaki; Kato, Takeshi; Yatagai, Fumio; Watanabe, Masami

    2003-12-01

    We investigated the difference in cell-killing effect and mutation induction between carbon- and neon-ion beams in normal human cells. Carbon- and neon-ion beams were accelerated by the Riken Ring Cyclotron (RRC) at the Institute of Physical and Chemical Research in Japan. Cell-killing effect was measured as the reproductive cell death using the colony formation assay. Mutation induction at the HPRT locus was detected to measure 6-thioguanine-resistant clones. The mutation spectrum of the deletion pattern of exons of induced mutants was analyzed using the multiplex polymerase chain reaction (PCR). Cell-killing effect was almost the same between carbon- and neon-ion beams with similar linear energy transfer (LET) values, while there observed a large difference in mutation frequency. Furthermore, in the case of neon-ion beams 60% of mutants showed total deletions and 35-40% showed partial deletions, while 95-100% of carbon-ion induced mutants showed total deletions. The results suggest that different ion species may cause qualitative and quantitative difference in mutation induction even if the LET values are similar.

  13. Observations and simulations of nova Vul 1984 no. 2: A nova with ejecta rich in oxygen, neon, and magnesium

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Sonneborn, G.; Stryker, L. L.; Sparks, Warren M.; Truran, James W.; Ferland, Gary; Wagner, R. M.; Gallagher, J. S.; Wade, R.; Williams, R. E.

    1988-01-01

    Nova Vul 1984 no. 2 was observed with IUE from Dec. 1984 through Nov. 1987. The spectra are characterized by strong lines from Mg, Ne, C, Si, O, N, and other elements. Data obtained in the ultraviolet, infrared, and optical show that this nova is ejecting material rich in oxygen, neon, and magnesium.

  14. Infrared transmission at the 3.39 micron helium-neon laser wavelength in liquid-core quartz fibers

    NASA Technical Reports Server (NTRS)

    Majumdar, A. K.; Hinkley, E. D.; Menzies, R. T.

    1979-01-01

    Infrared transmission at the 3.39 micron helium-neon laser wavelength has been measured in a tetrachloroethylene-filled fused-quartz fiber. The loss measurements were taken for three different settings of laser light intensity using a series of neutral density filters. The average value of transmission loss at this wavelength was found to be 56 dB/km.

  15. Correlated helium, neon, and melt production on the super-fast spreading East Pacific Rise near 17°S

    NASA Astrophysics Data System (ADS)

    Kurz, Mark D.; Moreira, Manuel; Curtice, Joshua; Lott, Dempsey E.; Mahoney, John J.; Sinton, John M.

    2005-03-01

    We report new helium and neon isotopic compositions in dredged basalt glasses from the superfast spreading East Pacific Rise (EPR) between 13° and 23°S. The 3He/ 4He ratios vary from 8.0 to 11.0 times the atmospheric value (Ra) [ 4He/ 3He between 65,700 and 90,300], with the least radiogenic values in samples from near 16.75°S. Atmospheric contamination corrections on neon isotopes are made using step heating and extrapolated 21Ne/ 22Ne ratios (to a solar 20Ne/ 22Ne value of 13.8). The lowest corrected 21Ne/ 22Ne ratios are found near 16.75°S, and are consistent with the helium isotopes in suggesting a less degassed mantle source. The EPR at 17°S is unusual in displaying such isotopic anomalies in the absence of any known hotspot. The minima in 4He/ 3He and 21Ne/ 22Ne correspond to extremes in Sr, Nd and Pb isotope ratios, but the length scale of the helium and neon anomalies are shorter along-axis than the peaks for the other isotopic ratios. The minimum in 4He/ 3He is observed from 16° to 18°S (a distance of ˜220 km), whereas the elevated Sr and Pb values, and lower 143Nd/ 144Nd, are observed between 16° and 20.7°S (a distance of ˜500 km); neon isotope anomalies are observed on an intermediate length scale along-axis. Unradiogenic helium and neon values correlate with low mantle Bouguer anomalies, and maxima in the axial cross-sectional area, all of which are attributed to higher melt production near 17°S. A conceptual model that fits the observations includes melting of an entrained heterogeneity beneath the EPR at 17 °S. The relationship between helium and neon isotopes and along-axis geophysical characteristics (and by inference melt distribution) is probably related to the extreme incompatibility of helium and neon. High concentrations of 3He and 21Ne (extrap) are found in the glasses near 17°S, which is consistent with higher noble gas concentrations in the anomalous mantle.

  16. Surface-subsurface flow modeling: an example of large-scale research at the new NEON user facility

    NASA Astrophysics Data System (ADS)

    Powell, H.; McKnight, D. M.

    2009-12-01

    Climate change is predicted to alter surface-subsurface interactions in freshwater ecosystems. These interactions are hypothesized to control nutrient release at diel and seasonal time scales, which may then exert control over epilithic algal growth rates. The mechanisms underlying shifts in complex physical-chemical-biological patterns can be elucidated by long-term observations at sites that span hydrologic and climate gradients across the continent. Development of the National Ecological Observatory Network (NEON) will provide researchers the opportunity to investigate continental-scale patterns by combining investigator-driven measurements with Observatory data. NEON is a national-scale research platform for analyzing and understanding the impacts of climate change, land-use change, and invasive species on ecology. NEON features sensor networks and experiments, linked by advanced cyberinfrastructure to record and archive ecological data for at least 30 years. NEON partitions the United States into 20 ecoclimatic domains. Each domain hosts one fully instrumented Core Aquatic site in a wildland area and one Relocatable site, which aims to capture ecologically significant gradients (e.g. landuse, nitrogen deposition, urbanization). In the current definition of NEON there are 36 Aquatic sites: 30 streams/rivers and 6 ponds/lakes. Each site includes automated, in-situ sensors for groundwater elevation and temperature; stream flow (discharge and stage); pond water elevation; atmospheric chemistry (Tair, barometric pressure, PAR, radiation); and surface water chemistry (DO, Twater, conductivity, pH, turbidity, cDOM, nutrients). Groundwater and surface water sites shall be regularly sampled for selected chemical and isotopic parameters. The hydrologic and geochemical monitoring design provides basic information on water and chemical fluxes in streams and ponds and between groundwater and surface water, which is intended to support investigator-driven modeling studies

  17. First demonstration of rapid shutdown using neon shattered pellet injection for thermal quench mitigation on DIII-D

    NASA Astrophysics Data System (ADS)

    Commaux, N.; Shiraki, D.; Baylor, L. R.; Hollmann, E. M.; Eidietis, N. W.; Lasnier, C. J.; Moyer, R. A.; Jernigan, T. C.; Meitner, S. J.; Combs, S. K.; Foust, C. R.

    2016-04-01

    Shattered pellet injection (SPI) is one of the prime candidates for the ITER disruption mitigation system because of its deeper penetration and larger particle flux than massive gas injection (MGI) (Taylor et al 1999 Phys. Plasmas 6 1872) using deuterium (Commaux et al 2010 Nucl. Fusion 50 112001, Combs et al 2010 IEEE Trans. Plasma Sci. 38 400, Baylor et al 2009 Nucl. Fusion 49 085013). The ITER disruption mitigation system will likely use mostly high Z species such as neon because of more effective thermal mitigation and pumping constraints on the maximum amount of deuterium or helium that could be injected. An upgrade of the SPI on DIII-D enables ITER relevant injection characteristics in terms of quantities and gas species. This upgraded SPI system was used on DIII-D for the first time in 2014 for a direct comparison with MGI using identical quantities of neon. This comparison enabled the measurements of density perturbations during the thermal quench (TQ) and radiated power and heat loads to the divertor. It showed that SPI using similar quantities of neon provided a faster and stronger density perturbation and neon assimilation, which resulted in a lower conducted energy to the divertor and a faster TQ onset. Radiated power data analysis shows that this was probably due to the much deeper penetration of the neon in the plasma inducing a higher core radiation than in the MGI case. This experiment shows also that the MHD activity during an SPI shutdown (especially during the TQ) is quite different compared to MGI. This favorable TQ energy dissipation was obtained while keeping the current quench (CQ) duration within acceptable limits when scaled to ITER.

  18. First demonstration of rapid shutdown using neon shattered pellet injection for thermal quench mitigation on DIII-D

    DOE PAGES

    Commaux, Nicolas J. C.; Shiraki, Daisuke; Baylor, Larry R.; ...

    2016-03-02

    Shattered pellet injection (SPI) is one of the prime candidates for the ITER disruption mitigation system because of its deeper penetration and larger particle flux than massive gas injection (MGI) (Taylor et al 1999 Phys. Plasmas 6 1872) using deuterium (Commaux et al 2010 Nucl. Fusion 50 112001, Combs et al 2010 IEEE Trans. Plasma Sci. 38 400, Baylor et al 2009 Nucl. Fusion 49 085013). The ITER disruption mitigation system will likely use mostly high Z species such as neon because of more effective thermal mitigation and pumping constraints on the maximum amount of deuterium or helium that couldmore » be injected. An upgrade of the SPI on DIII-D enables ITER relevant injection characteristics in terms of quantities and gas species. This upgraded SPI system was used on DIII-D for the first time in 2014 for a direct comparison with MGI using identical quantities of neon. This comparison enabled the measurements of density perturbations during the thermal quench (TQ) and radiated power and heat loads to the divertor. It showed that SPI using similar quantities of neon provided a faster and stronger density perturbation and neon assimilation, which resulted in a lower conducted energy to the divertor and a faster TQ onset. Radiated power data analysis shows that this was probably due to the much deeper penetration of the neon in the plasma inducing a higher core radiation than in the MGI case. This experiment shows also that the MHD activity during an SPI shutdown (especially during the TQ) is quite different compared to MGI. Furthermore, this favorable TQ energy dissipation was obtained while keeping the current quench (CQ) duration within acceptable limits when scaled to ITER.« less

  19. Calibration and Data Efforts of the National Ecological Observatory Network (NEON) Airborne Observation Platform during its Engineering Development Phase

    NASA Astrophysics Data System (ADS)

    Adler, J.; Goulden, T.; Kampe, T. U.; Leisso, N.; Musinsky, J.

    2014-12-01

    The National Ecological Observatory Network (NEON) has collected airborne photographic, lidar, and imaging spectrometer data in 5 of 20 unique ecological climate regions (domains) within the United States. As part of its mission to detect and forecast ecological change at continental scales over multiple decades, NEON Airborne Observation Platform (AOP) will aerially survey the entire network of 60 core and re-locatable terrestrial sites annually, each of which are a minimum of 10km-by-10km in extent. The current effort encompasses three years of AOP engineering test flights; in 2017 NEON will transition to full operational status in all 20 domains. To date the total airborne data collected spans 34 Terabytes, and three of the five sampled domain's L1 data are publically available upon request. The large volume of current data, and the expected data collection over the remaining 15 domains, is challenging NEON's data distribution plans, backup capability, and data discovery processes. To provide the public with the highest quality data, calibration and validation efforts of the camera, lidar, and spectrometer L0 data are implemented to produce L1 datasets. Where available, the collected airborne measurements are validated against ground reference points and surfaces and adjusted for instrumentation and atmospheric effects. The imaging spectrometer data is spectrally and radiometrically corrected using NIST-traceable procedures. This presentation highlights three years of flight operation experiences including:1) Lessons learned on payload re-configuration, data extraction, data distribution, permitting requirements, flight planning, and operational procedures2) Lidar validation through control data comparisons collected at the Boulder Municipal Airport (KBDU), the site of NEON's new hangar facility3) Spectrometer calibration efforts, to include both the laboratory and ground observations

  20. Synthesis and structural characterization of C(OTeF5)4 and a comparative structural study of the isoelectronic B(OTeF5)4- anion.

    PubMed

    Moran, Matthew D; Mercier, Hélène P A; Schrobilgen, Gary J

    2007-06-11

    Tetrakis(pentafluoroorthotellurate)carbon(IV), C(OTeF5)4, was synthesized by reaction of CBr4 with BrOTeF5 in SO2ClF solution at -78 degrees C and was isolated as a colorless, crystalline solid that is room-temperature stable in SO2ClF and in the solid state. Both natural abundance and 99% 13C-enriched C(OTeF5)4 have been characterized in SO2ClF solution by 13C, 19F, and 125Te NMR spectroscopy. In contrast, C(OTeF5)4 undergoes rapid decomposition to O(TeF5)2 and CO2 in CH3CN at 10 degrees C but is stable at -40 degrees C. The X-ray crystal structures of C(OTeF5)4 and [N(CH3)4][B(OTeF5)4] were determined at -30 and -170 degrees C, respectively. The averages of four smaller C/B-O-Te bond angles and O...O contacts and two larger C/B-O-Te bond angles and O...O contacts of C(OTeF5)4 and the isoelectronic B(OTeF5)4- anion are consistent with local S4 symmetry, as predicted by ligand close packing considerations. The existence of three sets of Te-O-C/B-O torsion angles and the energy-minimized geometries of C(OTeF5)4 and B(OTeF5)4- also confirm their local S4 symmetries. The low-temperature, solid-state Raman spectra of 12/13C(OTeF5)4 and B(OTeF5)4- were assigned and compared. The energy-minimized geometries, vibrational frequencies, natural charges, and natural bond orders of both species have been calculated using density functional theory methods. The calculated geometries are in accord with the S4 symmetries assigned for the experimental structures.

  1. Source of Volatiles in Earth's Deep Mantle from Neon Isotope Systematics in the South Atlantic

    NASA Astrophysics Data System (ADS)

    Williams, C. D.; Mukhopadhyay, S.

    2016-12-01

    The noble gases play an important role in understanding Earth's accretion and subsequent evolution. Neon isotopes in particular have the potential to distinguish between distinct sources of Earth's volatiles e.g., acquisition of nebular gas, solar wind implanted materials or chondritic meteorites and their components. The neon isotopic composition of the deep mantle remains subject to debate with the majority of mantle-derived basalts displaying maximum 20Ne/22Ne ratios less than 12.5, similar to values determined for the convective mantle (20Ne/22Ne = 12.49 +/- 0.04; [1]). These values are also much lower than those of solar wind (20Ne/22Ne = 13.8; [2,3]) and estimates of the nebular gas (20Ne/22Ne = 13.4; [4]) but comparable to solar wind implanted meteoritic materials (20Ne/22Ne = 12.5-12.7; [5]). Here we determine the neon isotopic composition of mantle-derived materials from the south Atlantic. These samples display strong linear correlations in 20Ne/22Ne-21Ne/22Ne space with maximum 20Ne/22Ne ratios that are resolvable from and higher than materials derived from the convecting mantle as well as models of solar wind implantation. These results supplement a growing database of mantle materials characterized by 20Ne/22Ne ratios greater than 12.5, challenging the notion that the entire mantle acquired volatiles from solar wind implanted meteoritic materials. In this presentation we will explore alternative origins for these volatiles and provide testable predictions for each scenario. [1] G. Holland, C.J. Ballentine.. Nature 441 (2006), 186-191. [2] A. Gimberg et al. GCA 72 (2008), 626-645. [3] V.S. Heber et al. GCA 73 (2009), 7414-7432. [4] V. S. Heber et al. ApJ 759 (2012), 121. [5] R. Wieler in: D. Porcelli, C.J. Ballentine, R. Wieler (Eds.), Reviews in Mineralogy and Geochemistry 47 (2002), 21-70.

  2. Cross sections for bare and dressed carbon ions in water and neon.

    PubMed

    Liamsuwan, Thiansin; Nikjoo, Hooshang

    2013-02-07

    The paper presents calculated cross sections for bare and dressed carbon projectiles of charge states q (0 to 6) with energies 1-10(4) keV u(-1) impacting on molecular water and atomic neon targets. The cross sections of water are of interest for radiobiological studies, but there are very few experimental data for water in any phase, while those for liquid water are non-existent. The more extensive experimental database for the neon target made it possible to test the reliability of the model calculations for the many-electron collision system. The current calculations cover major single and double electronic interactions of low and intermediate energy carbon projectiles. The three-body classical trajectory Monte Carlo (CTMC) method was used for the calculation of one-electron transition probabilities for target ionization, electron capture and projectile electron loss. The many-electron problem was taken into account using statistical methods: a modified independent event model was used for pure (direct) and simultaneous target and projectile ionizations, and the independent particle model for pure electron capture and electron capture accompanied by target ionization. Results are presented for double differential cross sections (DDCS) for total electron emission by carbon projectile impact on neon. For the water target, we present the following: single differential cross sections (SDCS) and DDCS for single target ionization; total cross sections (TCS) for electron emission; TCS for the pure single electronic interactions; equilibrium charge state fractions; and stopping cross sections. The results were found to be in satisfactory agreement with the experimental data in many cases, including DDCS and SDCS for the single target ionization, TCS for the total electron emission and TCS for the pure single electron capture. The stopping cross sections of this work are consistent with the other model calculations for projectile energies ≥800 keV u(-1), but smaller

  3. Reduced absorption of neon-like bromine X-ray laser radiation in helium

    NASA Astrophysics Data System (ADS)

    Lu, P.; Fill, E. E.

    1999-10-01

    We have measured the absorption of the 19.47-nm neon like bromine (J=2-1) X-ray laser line in low-pressure helium. The experiment was motivated by the coincidence of this line with the low-absorption wing of an autoionizing transition in helium. We observe that, with 1 mbar of helium, the continuum background and another bromine X-ray laser line at 19.82 nm are strongly reduced, enhancing the relative strength of the 19.47-nm laser line. Increasing the helium pressure to 1.5 mbar makes the continuum virtually disappear, resulting in an almost monochromatic emission of the X-ray laser line. An estimate of the absorption cross section for the 19.47-nm line is given as ≈3.9×10-19 cm2 and for the nearby continuum as 0.9-1.3×10-18 cm2.

  4. Above-threshold ionization in neon produced by combining optical and bichromatic XUV femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Douguet, Nicolas; Grum-Grzhimailo, Alexei N.; Bartschat, Klaus

    2017-01-01

    We consider the ionization of neon induced by a femtosecond laser pulse composed of overlapping, linearly polarized bichromatic extreme ultraviolet and infrared fields. In particular, we study the effects of infrared light on a two-pathway ionization scheme for which Ne 2 s22 p53 s 1P is used as the intermediate state. Using time-dependent calculations, supported by a theoretical approach based on the strong-field approximation, we analyze the ionization probability and the photoelectron angular distributions associated with the different sidebands of the ionization spectrum. Complex oscillations of the angular distribution anisotropy parameters as a function of the infrared light intensity are revealed. Finally, we demonstrate that coherent control of the asymmetry is achievable by tuning the infrared frequency to a nearby electronic transition.

  5. Electronic transitions of C5H+ and C5H: neon matrix and CASPT2 studies

    NASA Astrophysics Data System (ADS)

    Fulara, Jan; Nagy, Adam; Chakraborty, Arghya; Maier, John P.

    2016-06-01

    Two electronic transitions at 512.3 and 250 nm of linear-C5H+ are detected following mass-selective deposition of m/z = 61 cations into a 6 K neon matrix and assigned to the 1 1Π←X 1Σ+ and 1 1Σ+←X 1Σ+ systems. Five absorption systems of l-C5H with origin bands at 528,7, 482.6, 429.0, 368.5, and 326.8 nm are observed after neutralization of the cations in the matrix and identified as transitions from the X 2Π to 1 2Δ, 1 2Σ -, 1 2Σ+, 2 2Π, and 3 2Π electronic states. The assignment to specific structures is based on calculated excitation energies, vibrational frequencies in the electronic states, along with simulated Franck-Condon profiles.

  6. Integrating continental-scale ecological data into university courses: Developing NEON's Online Learning Portal

    NASA Astrophysics Data System (ADS)

    Wasser, L. A.; Gram, W.; Lunch, C. K.; Petroy, S. B.; Elmendorf, S.

    2013-12-01

    'Big Data' are becoming increasingly common in many fields. The National Ecological Observatory Network (NEON) will be collecting data over the 30 years, using consistent, standardized methods across the United States. Similar efforts are underway in other parts of the globe (e.g. Australia's Terrestrial Ecosystem Research Network, TERN). These freely available new data provide an opportunity for increased understanding of continental- and global scale processes such as changes in vegetation structure and condition, biodiversity and landuse. However, while 'big data' are becoming more accessible and available, integrating big data into the university courses is challenging. New and potentially unfamiliar data types and associated processing methods, required to work with a growing diversity of available data, may warrant time and resources that present a barrier to classroom integration. Analysis of these big datasets may further present a challenge given large file sizes, and uncertainty regarding best methods to properly statistically summarize and analyze results. Finally, teaching resources, in the form of demonstrative illustrations, and other supporting media that might help teach key data concepts, take time to find and more time to develop. Available resources are often spread widely across multi-online spaces. This presentation will overview the development of NEON's collaborative University-focused online education portal. Portal content will include 1) interactive, online multi-media content that explains key concepts related to NEON's data products including collection methods, key metadata to consider and consideration of potential error and uncertainty surrounding data analysis; and 2) packaged 'lab' activities that include supporting data to be used in an ecology, biology or earth science classroom. To facilitate broad use in classrooms, lab activities will take advantage of freely and commonly available processing tools, techniques and scripts. All

  7. Liquid neon heat transfer as applied to a 30 tesla cryomagnet

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Hendricks, R. C.

    1975-01-01

    Since superconducting magnets cooled by liquid helium are limited to magnetic fields of about 18 teslas, the design of a 30 tesla cryomagnet necessitates forced convection liquid neon heat transfer in small coolant channels. As these channels are too small to handle the vapor flow if the coolant were to boil, the design philosophy calls for suppressing boiling by subjecting the fluid to high pressures. Forced convection heat transfer data are obtained by using a blowdown technique to force the fluid vertically through a resistance-heated instrumented tube. The data are obtained at inlet temperatures between 28 and 34 K and system pressures between 28 to 29 bars. Data correlation is limited to a very narrow range of test conditions, since the tests were designed to simulate the heat transfer characteristics in the coolant channels of the 30 tesla cryomagnet concerned. The results can therefore be applied directly to the design of the magnet system.-

  8. Time delay between photoemission from the 2p and 2s subshells of Neon atoms

    NASA Astrophysics Data System (ADS)

    Moore, L. R.; Lysaght, M. A.; Nikolopoulos, L. A. A.; Parker, J. S.; van der Hart, H. W.; Taylor, K. T.

    2012-11-01

    The R-Matrix incorporating Time (RMT) method is a new ab initio method for solving the time-dependent Schrödinger equation for multi-electron atomic systems exposed to intense short-pulse laser light. We have employed the RMT method to investigate the delay in the photoemission of an electron liberated from a 2p orbital in a neon atom with respect to one released from a 2s orbital. Using attosecond streaking methods, an experimental group measured this time delay to be twenty one attoseconds. We report RMT calculations of this time delay and demonstrate that such precise phase-sensitive information can be calculated using the new multi-electron RMT method.

  9. Solar flare neon and solar cosmic ray fluxes in the past using gas-rich meteorites

    NASA Technical Reports Server (NTRS)

    Nautiyal, C. M.; Rao, M. N.

    1986-01-01

    Methods were developed earlier to deduce the composition of solar flare neon and to determine the solar cosmic ray proton fluxes in the past using etched lunar samples and at present, these techniques are extended to gas rich meteorites. By considering high temperature Ne data points for Pantar, Fayetteville and other gas rich meteorites and by applying the three component Ne-decomposition methods, the solar cosmic ray and galactic cosmic ray produced spallation Ne components from the trapped SF-Ne was resolved. Using appropiate SCR and GCR production rates, in the case of Pantar, for example, a GCR exposure age of 2 m.y. was estimated for Pantar-Dark while Pantar-Light yielded a GCR age of approx. 3 m.y. However the SCR exposure age of Pantar-Dark is two orders of magnitude higher than the average surface exposure ages of lunar soils. The possibility of higher proton fluxes in the past is discussed.

  10. Connected triple excitations in coupled-cluster calculations of hyperpolarizabilities: Neon

    NASA Technical Reports Server (NTRS)

    Rice, Julia E.; Scuseria, Gustavo E.; Lee, Timothy J.; Taylor, Peter R.; Almloef, Jan

    1992-01-01

    We have calculated the second hyperpolarizability gamma of neon using the CCSD(T) method. The accuracy of the CCSD(T) approach has been established by explicit comparison with the single, double and triple excitation coupled-cluster (CCSDT) method using extended basis sets that are known to be adequate for the description of gamma. Our best estimate for gamma(sub 0) of 110 +/- 3 a.u. is in good agreement with other recent theoretical values and with Shelton's recent experimental estimate of 108 +/- 2 a.u. Comparison of the MP2 and CCSD(T) hyperpolarizability values indicates that MP2 gives a very good description of the electron correlation contribution to gamma(sub 0). We have combined MP2 frequency-dependent corrections with the CCSD(T) gamma(sub 0) to yield values of gamma(-2 omega;omega,omega,0) and gamma(exp K)(-omega;omega,0,0).

  11. High resolution measurements of galactic cosmic-ray neon, magnesium, and silicon isotopes

    NASA Technical Reports Server (NTRS)

    Mewaldt, R. A.; Spalding, J. D.; Stone, E. C.; Vogt, R. E.

    1980-01-01

    High-resolution measurements of the abundances of individual isotopes of neon, magnesium and silicon in galactic cosmic rays are reported. The Caltech Heavy Isotope Spectrometer Telescope on board the ISEE 3 spacecraft was used to obtain measurements in the range 30 to 180 MeV/n at an rms mass resolution of 0.20 amu. Results indicate excesses of Ne-22 as well as Mg-25 and Mg-26 in galactic cosmic rays with respect to their solar system abundances. Calculations of the effects of interstellar propagation and solar modulation on cosmic-ray isotope abundances also imply an Mg-25 + Mg-26 cosmic ray source fraction significantly greater than the solar system fraction, and it is suggested that the cosmic ray source material and solar system material were synthesized under different conditions.

  12. Electron-Impact-Induced Emission Cross Sections of Neon in the Extreme Ultraviolet

    NASA Technical Reports Server (NTRS)

    Kanik, I.; Ajello, J. M.; James, G. K.

    1996-01-01

    We have measured the extreme ultraviolet (EUV) spectrum of neon produced by electron excitation. The measurements were obtained under optically thin conditions, and at a spectral resolution of 0.5 nm full width at half maximum (FWHM). The most prominent features of the EUV spectrum between 45-80 nm are the resonance lines of Ne I at 73.6 and 74.4 nm and a multiplet of Ne II at 46.14 nm (the average value for the line center of the two closely spaced ion lines at 46.07 and 46.22 nm). Absolute emission cross sections of these lines at 300 eV were measured and compared to other previous measurements.

  13. Neural control of motile activity of light-sensitive iridophores in the neon tetra.

    PubMed

    Nagaishi, H; Oshima, N

    1989-01-01

    Experiments with skin pieces revealed that the sympathetic nervous system controls the activity of the light-sensitive iridophores in the stripes of the neon tetra. The spectral peak reflected from the cells was shifted toward longer wavelengths as a result of a direct interaction between norepinephrine and alpha-adrenoceptors present on the cell membrane. Adenosine accelerated the recovery from the effects of the amine. Such regulation seems to operate when fish are in an excited state or under stress. Since alpha-melanophore-stimulating hormone (alpha-MSH), melanin-concentrating hormone (MCH) and melatonin caused the responses only at high concentrations, it is possible that these peptides and amine do not affect the properties of the light-reflecting cells in vivo.

  14. Light-induced colour changes by the iridophores of the Neon tetra, Paracheirodon innesi.

    PubMed

    Clothier, J; Lythgoe, J N

    1987-12-01

    The iridophores of the Neon tetra Paracheirodon innesi consist of alternating layers of guanine and cytoplasm. In the dark-adapted state the reflected light from constructive interference is in the ultraviolet or blue. When exposed to light the cytoplasm layers increase in thickness and as a result the reflections shift to longer wavelengths and the iridophores appear green. The iridophores are thought to contain a rhodopsin-like molecule and we suggest that the colour-change mechanism involves the light-induced opening of sodium channels in the plasma membrane, leading osmotically to an increase in thickness of the cytoplasm layers. Experimental support for this suggestion was obtained by the substitution of choline chloride for sodium chloride in the perfusing medium, which can be done without altering the osmotic strength of the perfusing medium. This procedure almost abolished the light response and makes it seem likely that sodium ions are necessary for the light response to take place.

  15. Angular correlation between photoelectrons and auger electrons from K-shell ionization of neon.

    PubMed

    Landers, A L; Robicheaux, F; Jahnke, T; Schöffler, M; Osipov, T; Titze, J; Lee, S Y; Adaniya, H; Hertlein, M; Ranitovic, P; Bocharova, I; Akoury, D; Bhandary, A; Weber, Th; Prior, M H; Cocke, C L; Dörner, R; Belkacem, A

    2009-06-05

    We have used cold target recoil ion momentum spectroscopy to study the continuum correlation between the photoelectron of core-photoionized neon and the subsequent Auger electron. We observe a strong angular correlation between the two electrons. Classical trajectory Monte Carlo calculations agree quite well with the photoelectron energy distribution that is shifted due to the potential change associated with Auger decay. However, a striking discrepancy results in the distribution of the relative angle between Auger and photoelectron. The classical model predicts a shift in photoelectron flux away from the Auger emission direction, and the data strikingly reveal that the flux is lost rather than diverted, indicating that the two-step interpretation of photoionization followed by Auger emission is insufficient to fully describe the core-photoionization process.

  16. Angular Correlation between Photoelectrons and Auger Electrons from K-Shell Ionization of Neon

    SciTech Connect

    Landers, A. L.; Robicheaux, F.; Bhandary, A.; Jahnke, T.; Schoeffler, M.; Titze, J.; Akoury, D.; Doerner, R.; Osipov, T.; Lee, S. Y.; Adaniya, H.; Hertlein, M.; Weber, Th.; Prior, M. H.; Belkacem, A.; Ranitovic, P.; Bocharova, I.; Cocke, C. L.

    2009-06-05

    We have used cold target recoil ion momentum spectroscopy to study the continuum correlation between the photoelectron of core-photoionized neon and the subsequent Auger electron. We observe a strong angular correlation between the two electrons. Classical trajectory Monte Carlo calculations agree quite well with the photoelectron energy distribution that is shifted due to the potential change associated with Auger decay. However, a striking discrepancy results in the distribution of the relative angle between Auger and photoelectron. The classical model predicts a shift in photoelectron flux away from the Auger emission direction, and the data strikingly reveal that the flux is lost rather than diverted, indicating that the two-step interpretation of photoionization followed by Auger emission is insufficient to fully describe the core-photoionization process.

  17. Angular Correlation between Photoelectrons and Auger Electrons from K-Shell Ionization of Neon

    NASA Astrophysics Data System (ADS)

    Landers, A. L.; Robicheaux, F.; Jahnke, T.; Schöffler, M.; Osipov, T.; Titze, J.; Lee, S. Y.; Adaniya, H.; Hertlein, M.; Ranitovic, P.; Bocharova, I.; Akoury, D.; Bhandary, A.; Weber, Th.; Prior, M. H.; Cocke, C. L.; Dörner, R.; Belkacem, A.

    2009-06-01

    We have used cold target recoil ion momentum spectroscopy to study the continuum correlation between the photoelectron of core-photoionized neon and the subsequent Auger electron. We observe a strong angular correlation between the two electrons. Classical trajectory Monte Carlo calculations agree quite well with the photoelectron energy distribution that is shifted due to the potential change associated with Auger decay. However, a striking discrepancy results in the distribution of the relative angle between Auger and photoelectron. The classical model predicts a shift in photoelectron flux away from the Auger emission direction, and the data strikingly reveal that the flux is lost rather than diverted, indicating that the two-step interpretation of photoionization followed by Auger emission is insufficient to fully describe the core-photoionization process.

  18. Characterization of a metastable neon beam extracted from a commercial RF ion source

    NASA Astrophysics Data System (ADS)

    Ohayon, B.; Wåhlin, E.; Ron, G.

    2015-03-01

    We have used a commercial RF ion-source to extract a beam of metastable neon atoms. The source was easily incorporated into our existing system and was operative within a day of installation. The metastable velocity distribution, flux, flow, and efficiency were investigated for different RF powers and pressures, and an optimum was found at a flux density of 2 × 1012 atoms/s/sr. To obtain an accurate measurement of the amount of metastable atoms leaving the source, we insert a Faraday cup in the beam line and quench some of them using a weak 633 nm laser beam. In order to determine how much of the beam was quenched before reaching our detector, we devised a simple model for the quenching transition and investigated it for different laser powers. This detection method can be easily adapted to other noble gas atoms.

  19. Measurements of ion mobility in argon and neon based gas mixtures

    NASA Astrophysics Data System (ADS)

    Deisting, Alexander; Garabatos, Chilo; Szabo, Alexander; Vranic, Danilo

    2017-02-01

    As gaseous detectors are operated at high rates of primary ionisation, ions created in the detector have a considerable impact on the performance of the detector. The upgraded ALICE Time Projection Chamber (TPC) will operate during LHC Run 3 with a substantial space charge density of positive ions in the drift volume. In order to properly simulate such space charges, knowledge of the ion mobility K is necessary. To this end, a small gaseous detector was constructed and the ion mobility of various gas mixtures was measured. To validate the corresponding signal analysis, simulations were performed. Results are shown for several argon and neon based mixtures with different CO2 fractions. A decrease of K was measured for increasing water content.

  20. Molecular iodine fluorescence spectra generated with helium-neon lasers for spectrometer calibration.

    PubMed

    Williamson, J Charles

    2010-12-01

    Gas-phase molecular iodine laser-induced fluorescence (LIF) spectra were recorded out to 815 nm at 1 cm(-1) resolution using green, yellow, and red helium-neon (HeNe) lasers as excitation sources. Nine previously unreported I(2) B←X absorption transitions accessed by these lasers were identified, and specific rovibronic transition assignments were made for two hundred LIF peaks--more than sixty per laser. These I(2) LIF peaks can be used to calibrate the vacuum wavenumber coordinate of spectrometers to better than 0.1 cm(-1) accuracy. In particular, green HeNe excitation of the I(2) R(106) 28-0 transition leads to strong fluorescence well suited for calibration, with a rotational doublet spacing of 15 cm(-1) and a doublet-to-doublet spacing of 190 cm(-1). Calibration by HeNe I(2) LIF may be an especially valuable technique for Raman spectroscopy applications.

  1. Ion-impact-induced interatomic Coulombic decay in neon and argon dimers

    NASA Astrophysics Data System (ADS)

    Kim, H.-K.; Gassert, H.; Schöffler, M. S.; Titze, J. N.; Waitz, M.; Voigtsberger, J.; Trinter, F.; Becht, J.; Kalinin, A.; Neumann, N.; Zhou, C.; Schmidt, L. Ph. H.; Jagutzki, O.; Czasch, A.; Merabet, H.; Schmidt-Böcking, H.; Jahnke, T.; Cassimi, A.; Dörner, R.

    2013-10-01

    We investigate the contribution of interatomic Coulombic decay induced by ion impact in neon and argon dimers (Ne2 and Ar2) to the production of low-energy electrons. Our experiments cover a broad range of perturbation strengths and reaction channels. We use 11.37 MeV/u S14+, 0.125 MeV/u He1+, 0.1625 MeV/u He1+, and 0.150 MeV/u He2+ as projectiles and study ionization, single and double electron transfer to the projectile, as well as projectile electron loss processes. The application of a COLTRIMS reaction microscope enables us to retrieve the three-dimensional momentum vectors of the ion pairs of the fragmenting dimer into Neq+-Ne1+ and Arq+-Ar1+ (q= 1, 2, 3) in coincidence with at least one emitted electron.

  2. Adsorption of neon and tetrafluoromethane on carbon nanohorn aggregates: differences in specific surface area values

    NASA Astrophysics Data System (ADS)

    Krungleviciute, Vaiva; Yudasaka, Masako; Iijima, Sumio; Migone, Aldo

    2008-03-01

    We have measured adsorption isotherms for two different adsorbates, neon and tetrafluoromethane, on dahlia-like carbon nanohorn aggregates. The experiments were performed at similar relative temperatures for both gases. The measurements were conducted to explore the effect of adsorbate diameter on the behavior of the resulting adsorbed systems. We measured the effective specific surface area value of the nanohorn sample using both gases, and we found that this quantity was about 22% smaller when we determined this quantity using tetrafluoromethane, the larger molecule. Isosteric heat and binding energy values were also determined from our measurements. We will compare our experimental results with those from a computer simulation study performed by Prof. M. Calbi. The simulations help us understand the source of the observed differences in the measured specific surface values, as well as the coverage dependence of the isosteric heat of adsorption for both gases.

  3. Electronic transitions of C5H(+) and C5H: neon matrix and CASPT2 studies.

    PubMed

    Fulara, Jan; Nagy, Adam; Chakraborty, Arghya; Maier, John P

    2016-06-28

    Two electronic transitions at 512.3 and 250 nm of linear-C5H(+) are detected following mass-selective deposition of m/z = 61 cations into a 6 K neon matrix and assigned to the 1 (1)Π←X (1)Σ(+) and 1 (1)Σ(+)←X (1)Σ(+) systems. Five absorption systems of l-C5H with origin bands at 528,7, 482.6, 429.0, 368.5, and 326.8 nm are observed after neutralization of the cations in the matrix and identified as transitions from the X (2)Π to 1 (2)Δ, 1 (2)Σ (-), 1 (2)Σ(+), 2 (2)Π, and 3 (2)Π electronic states. The assignment to specific structures is based on calculated excitation energies, vibrational frequencies in the electronic states, along with simulated Franck-Condon profiles.

  4. Electron-Impact-Induced Emission Cross Sections of Neon in the Extreme Ultraviolet

    NASA Technical Reports Server (NTRS)

    Kanik, I.; Ajello, J. M.; James, G. K.

    1996-01-01

    We have measured the extreme ultraviolet (EUV) spectrum of neon produced by electron excitation. The measurements were obtained under optically thin conditions, and at a spectral resolution of 0.5 nm full width at half maximum (FWHM). The most prominent features of the EUV spectrum between 45-80 nm are the resonance lines of Ne I at 73.6 and 74.4 nm and a multiplet of Ne II at 46.14 nm (the average value for the line center of the two closely spaced ion lines at 46.07 and 46.22 nm). Absolute emission cross sections of these lines at 300 eV were measured and compared to other previous measurements.

  5. The watercolor illusion and neon color spreading: a unified analysis of new cases and neural mechanisms

    NASA Astrophysics Data System (ADS)

    Pinna, Baingio; Grossberg, Stephen

    2005-10-01

    Coloration and figural properties of neon color spreading and the watercolor illusion are studied using phenomenal and psychophysical observations. Coloration properties of both effects can be reduced to a common limiting condition, a nearby color transition called the two-dot limiting case, which clarifies their perceptual similarities and dissimilarities. The results are explained by the FACADE neural model of biological vision. The model proposes how local properties of color transitions activate spatial competition among nearby perceptual boundaries, with boundaries of lower-contrast edges weakened by competition more than boundaries of higher-contrast edges. This asymmetry induces spreading of more color across these boundaries than conversely. The model also predicts how depth and figure-ground effects are generated in these illusions.

  6. Effect of helium-neon laser irradiation on peripheral sensory nerve latency

    SciTech Connect

    Snyder-Mackler, L.; Bork, C.E.

    1988-02-01

    The purpose of this randomized, double-blind study was to determine the effect of a helium-neon (He-Ne) laser on latency of peripheral sensory nerve. Forty healthy subjects with no history of right upper extremity pathological conditions were assigned to either a Laser or a Placebo Group. Six 1-cm2 blocks along a 12-cm segment of the subjects' right superficial radial nerve received 20-second applications of either the He-Ne laser or a placebo. We assessed differences between pretest and posttest latencies with t tests for correlated and independent samples. The Laser Group showed a statistically significant increase in latency that corresponded to a decrease in sensory nerve conduction velocity. Short-duration He-Ne laser application significantly increased the distal latency of the superficial radial nerve. This finding provides information about the mechanism of the reported pain-relieving effect of the He-Ne laser.

  7. Atmospheric pressure plasma jet's characterization and surface wettability driven by neon transformer

    NASA Astrophysics Data System (ADS)

    Elfa, R. R.; Nafarizal, N.; Ahmad, M. K.; Sahdan, M. Z.; Soon, C. F.

    2017-03-01

    Atmospheric pressure plasma driven by Neon transformer power supply argon is presented in this paper. Atmospheric pressure plasma system has attracted researcher interest over low pressure plasma as it provides a flexibility process, cost-efficient, portable device and vacuum-free device. Besides, another golden key of this system is the wide promising application in the field of work cover from industrial and engineering to medical. However, there are still numbers of fundamental investigation that are necessary such as device configuration, gas configuration and its effect. Dielectric barrier discharge which is also known as atmospheric pressure plasma discharge is created when there is gas ionization process occur which enhance the movement of atom and electron and provide energetic particles. These energetic particles can provide modification and cleaning property to the sample surface due to the bombardment of the high reactive ion and radicals to the sample surface. In order to develop atmospheric pressure plasma discharge, a high voltage and high frequency power supply is needed. In this work, we used a neon transformer power supply as the power supply. The flow of the Ar is feed into 10 mm cylinder quartz tube with different treatment time in order to investigate the effect of the plasma discharge. The analysis of each treatment time is presented by optical emission spectroscopy (OES) and water contact angle (WCA) measurement. The increase of gas treatment time shows increases intensity of reactive Ar and reduces the angle of water droplets in water contact angle. Treatment time of 20 s microslide glass surface shows that the plasma needle discharges have modified the sample surface from hydrophilic surface to superhydrophilic surface. Thus, this leads to another interesting application in reducing sample surface adhesion to optimize productivity in the industry of paintings, semiconductor and more.

  8. Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial.

    PubMed

    Dixit, Snehil; Maiya, Arun; Rao, Laxmi; Rao, M Arjun; Shastry, Barkur Ananthakrishna; Ramachandra, L

    2012-01-01

    Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation. Was to find out the effect of irradiation with energy densities of 3.38 J/cm(2), 8 J/cm(2), and 18 J/cm(2) on animal tissue (albino wistar rats) in an excisional wound model and to assess changes in biochemical (hydroxyproline) and histopathological levels in excisional wound model. The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm(2)), L2 Helium-neon (He-Ne, 8 J/cm(2)), L3 diode laser (3.38 J/cm(2)), and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni's multiple comparison tests were done for tissue hydroxyproline levels. There was no significant increase in the hydroxyproline content (P < 0.005) when observed in study group and compared to controls. Whereas significant epithelizations was seen in group treated with He-Ne laser of intensity of 8 J/cm(2). The experimental observations suggest that low intensity helium-neon laser of 8 J/cm(2) intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model.

  9. Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial

    PubMed Central

    Dixit, Snehil; Maiya, Arun; Rao, Laxmi; Rao, M. Arjun; Shastry, Barkur Ananthakrishna; Ramachandra, L.

    2012-01-01

    Background: Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation. Objective: Was to find out the effect of irradiation with energy densities of 3.38 J/cm2, 8 J/cm2, and 18 J/cm2 on animal tissue (albino wistar rats) in an excisional wound model and to assess changes in biochemical (hydroxyproline) and histopathological levels in excisional wound model. Materials and Methods: The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm2), L2 Helium-neon (He-Ne, 8 J/cm2), L3 diode laser (3.38 J/cm2), and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni's multiple comparison tests were done for tissue hydroxyproline levels. Results: There was no significant increase in the hydroxyproline content (P < 0.005) when observed in study group and compared to controls. Whereas significant epithelizations was seen in group treated with He-Ne laser of intensity of 8 J/cm2. Conclusion: The experimental observations suggest that low intensity helium-neon laser of 8 J/cm2 intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model. PMID:23326769

  10. Ultraviolet and Infrared Spectra of Diboron in Solid Neon at 4 K.

    PubMed

    Lo, Jen-Iu; Chou, Sheng-Lung; Lu, Hsiao-Chi; Peng, Yu-Chain; Lin, Meng-Yeh; Cheng, Bing-Ming; Ogilvie, J F

    2017-01-04

    Apart from products H, B, BH, BH2 and BH3 identified from their emission spectra in the UV/Vis region, photolysis of diborane(6) dispersed in solid neon at 4 K with far-ultraviolet light from a synchrotron led to observation of absorption line (0,0) of the electronic transition A (3) Σu(-) ←X (3) Σg(-) of B2 at 326.39 nm. Absorption lines (1,0) of (11) B2 , (11) B(10) B and (10) B2 were recorded at 316.63, 316.40 and 316.15 nm, respectively. ΔG1/2 of state A (3) Σu(-) for (11) B2 , (11) B(10) B and (10) B2 in solid neon are accordingly derived to be 945, 968 and 993 cm(-1) , respectively. Weak lines (0,1) of (11) B2 at 29586 cm(-1) and of (11) B(10) B at 29560 cm(-1) , corresponding to 1042±30 and 1068±30 cm(-1) for vibrational modes in the electronic ground state, were recorded in emission. An absorption line recorded at 1066.5±0.5 cm(-1) in infrared spectra after photolysis of either B2 H6 in Ne or B2 D6 with D2 in Ne is thus attributed to (11) B(10) B. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The stereodynamics of the Penning ionization of water by metastable neon atoms.

    PubMed

    Brunetti, Brunetto Giovanni; Candori, Pietro; Falcinelli, Stefano; Pirani, Fernando; Vecchiocattivi, Franco

    2013-10-28

    The stereodynamics of the Penning ionization of water molecules by collision with metastable neon atoms, occurring in the thermal energy range, is of great relevance for the understanding of fundamental aspects of the physical chemistry of water. This process has been studied by analyzing the energy spectrum of the emitted electrons previously obtained in our laboratory in a crossed beam experiment [B. G. Brunetti, P. Candori, D. Cappelletti, S. Falcinelli, F. Pirani, D. Stranges, and F. Vecchiocattivi, Chem. Phys. Lett. 539-540, 19 (2012)]. For the spectrum analysis, a novel semiclassical method is proposed, that assumes ionization events as mostly occurring in the vicinities of the collision turning points. The potential energy driving the system in the relevant configurations of the entrance and exit channels, used in the spectrum simulation, has been formulated by the use of a semiempirical method. The analysis puts clearly in evidence how different approaches of the metastable atom to the water molecule lead to ions in different electronic states. In particular, it provides the angular acceptance cones where the selectivity of the process leading to the specific formation of each one of the two energetically possible ionic product states of H2O(+) emerges. It is shown how the ground state ion is formed when neon metastable atoms approach water mainly perpendicularly to the molecular plane, while the first excited electronic state is formed when the approach occurs preferentially along the C2v axis, on the oxygen side. An explanation is proposed for the observed vibrational excitation of the product ions.

  12. Kinetics of positive ions and electrically neutral active particles in afterglow in neon at low pressure

    SciTech Connect

    Pejović, Milić M. Nešić, Nikola T.; Pejović, Momčilo M.

    2014-04-15

    Kinetics of positive ions and electrically neutral active particles formed during breakdown and successive discharge in neon-filled tube at 6.6 millibars pressure had been analyzed. This analysis was performed on the basis of mean value of electrical breakdown time delay t{sup ¯}{sub d} dependence on afterglow period τ (memory curve). It was shown that positive ions are present in the 1μs < τ < 30 ms interval, which is manifested through t{sup ¯}{sub d} slow increase with the increase of τ. A rapid t{sup ¯}{sub d} increase in the 30 ms < τ < 3 s interval is a consequence of significant decrease of positive ions concentration and dominant role in breakdown initiation have ground state nitrogen atoms, which further release secondary electrons from the cathode by catalytic recombination process. These atoms are formed during discharge by dissociation of ground state nitrogen molecules that are present as impurities in neon. For τ > 3 s, breakdown is initiated by cosmic rays and natural radioactivity. The increase of discharge current leads to decrease of t{sup ¯}{sub d} due to the increase of positive ions concentration in inter electrode gap. The increase of applied voltage also decreases t{sup ¯}{sub d} for τ > 30 ms due to the increase of the probability for initial electron to initiate breakdown. The presence of UV radiation leads to the decrease of t{sup ¯}{sub d} due to the increased electron yield caused by photoelectrons. The influence of photoelectrons on breakdown initiation can be noticed for τ > 0.1 ms, while they dominantly determine t{sup ¯}{sub d} for τ > 30 ms.

  13. Acute toxicity of mixture of acetaminophen and ibuprofen to Green Neon Shrimp, Neocaridina denticulate.

    PubMed

    Sung, Hung-Hung; Chiu, Yuh-Wen; Wang, Shu-Yin; Chen, Chien-Min; Huang, Da-Ji

    2014-07-01

    In recent years, numerous studies have indicated that various long-term use drugs, such as antibiotics or analgesics, not only cannot be completely decomposed via sewage treatment but also exhibit biological toxicity if they enter the environment; thus, the release of these drugs into the environment can damage ecological systems. This study sought to investigate the acute toxicity of two commonly utilized analgesics, ibuprofen (IBU) and acetaminophen (APAP), to aquatic organisms after these drugs have entered the water. To address this objective, the acute toxicity (median lethal concentration, LC₅₀, for a 96-h exposure) of IBU alone, APAP alone, and mixtures containing different ratios of IBU and APAP in green neon shrimp (Neocaridina denticulata) were measured. The results of four tests revealed that the 96-h LC₅₀ values for IBU and APAP alone were 6.07 mg/L and 6.60 mg/L, respectively. The 96-h LC₅₀ for a 1:1 mixture of IBU and APAP was 6.23 mg/L, and the toxicity of this mixture did not significantly differ from the toxicity of either drug alone (p<0.05). The experimental results for mixtures containing unequal ratios of IBU and APAP indicated that mixtures with high APAP concentrations and low IBU concentrations exhibited markedly greater toxicity in N. denticulata (LC₅₀=4.78 mg/L) than APAP or IBU alone. However, mixtures with high IBU concentrations and low APAP concentrations exhibited lower toxicity in N. denticulata (LC₅₀=6.78 mg/L) than IBU or APAP alone. This study demonstrated that different mixtures of IBU and APAP were associated with different toxic effects in green neon shrimp.

  14. A HIGH-RESOLUTION ATLAS OF URANIUM-NEON IN THE H BAND

    SciTech Connect

    Redman, Stephen L.; Terrien, Ryan; Mahadevan, Suvrath; Ramsey, Lawrence W.; Bender, Chad F.; Ycas, Gabriel G.; Osterman, Steven N.; Diddams, Scott A.; Quinlan, Franklyn; Lawler, James E.; Nave, Gillian

    2012-03-01

    We present a high-resolution (R Almost-Equal-To 50,000) atlas of a uranium-neon (U/Ne) hollow-cathode spectrum in the H band (1454-1638 nm) for the calibration of near-infrared spectrographs. We obtained this U/Ne spectrum simultaneously with a laser-frequency comb spectrum, which we used to provide a first-order calibration to the U/Ne spectrum. We then calibrated the U/Ne spectrum using the recently published uranium line list of Redman et al., which is derived from high-resolution Fourier transform spectrometer measurements. These two independent calibrations allowed us to easily identify emission lines in the hollow-cathode lamp that do not correspond to known (classified) lines of either uranium or neon, and to compare the achievable precision of each source. Our frequency comb precision was limited by modal noise and detector effects, while the U/Ne precision was limited primarily by the signal-to-noise ratio (S/N) of the observed emission lines and our ability to model blended lines. The standard deviation in the dispersion solution residuals from the S/N-limited U/Ne hollow-cathode lamp was 50% larger than the standard deviation of the dispersion solution residuals from the modal-noise-limited laser-frequency comb. We advocate the use of U/Ne lamps for precision calibration of near-infrared spectrographs, and this H-band atlas makes these lamps significantly easier to use for wavelength calibration.

  15. The stereodynamics of the Penning ionization of water by metastable neon atoms

    NASA Astrophysics Data System (ADS)

    Brunetti, Brunetto Giovanni; Candori, Pietro; Falcinelli, Stefano; Pirani, Fernando; Vecchiocattivi, Franco

    2013-10-01

    The stereodynamics of the Penning ionization of water molecules by collision with metastable neon atoms, occurring in the thermal energy range, is of great relevance for the understanding of fundamental aspects of the physical chemistry of water. This process has been studied by analyzing the energy spectrum of the emitted electrons previously obtained in our laboratory in a crossed beam experiment [B. G. Brunetti, P. Candori, D. Cappelletti, S. Falcinelli, F. Pirani, D. Stranges, and F. Vecchiocattivi, Chem. Phys. Lett. 539-540, 19 (2012)]. For the spectrum analysis, a novel semiclassical method is proposed, that assumes ionization events as mostly occurring in the vicinities of the collision turning points. The potential energy driving the system in the relevant configurations of the entrance and exit channels, used in the spectrum simulation, has been formulated by the use of a semiempirical method. The analysis puts clearly in evidence how different approaches of the metastable atom to the water molecule lead to ions in different electronic states. In particular, it provides the angular acceptance cones where the selectivity of the process leading to the specific formation of each one of the two energetically possible ionic product states of H2O+ emerges. It is shown how the ground state ion is formed when neon metastable atoms approach water mainly perpendicularly to the molecular plane, while the first excited electronic state is formed when the approach occurs preferentially along the C2v axis, on the oxygen side. An explanation is proposed for the observed vibrational excitation of the product ions.

  16. Current Status and Future Plans of the NEON Airborne Observation Platform (AOP): Data Products, Observatory Requirements and Opportunities for the Community

    NASA Astrophysics Data System (ADS)

    Petroy, S. B.; Leisso, N.; Goulden, T.; Gulbransen, T.

    2016-12-01

    The National Ecological Observatory Network (NEON) is a continental-scale ecological observation platform designed to collect and disseminate data that contributes to understanding and forecasting the impacts of climate change, land use change, and invasive species on ecology. NEON will collect in-situ and airborne data over 81 sites across the US, including Alaska, Hawaii, and Puerto Rico. The Airborne Observation Platform (AOP) group within the NEON project operates a payload suite that includes a waveform LiDAR, imaging spectrometer (NIS) and high resolution RGB camera. Data from this sensor suite will be collected annually over each site and processed into a set of standard data products, generally following the processing levels used by NASA (Level 1 through Level 3). We will present a summary of the first operational flight campaign (2016), where AOP flew 42 of the 81 planned NEON sites, our operational plans for 2017, and how we will ramp up to full operations by 2018. We will also describe the final set of AOP data products to be delivered as part of NEON construction and those field (observational) data products collected concurrently on the ground, that may be used to support validation efforts of algorithms for deriving vegetation characteristics from airborne data (e.g. Plant foliar physical/chemical properties, Digital Hemispherical Photos, Plant Diversity, etc.). Opportunities for future enhancements to data products or algorithms will be facilitated via NEON's cyberinfrastructure, which is designed to support wrapping/integration of externally-developed code. And finally, we will present NEON's plans for the third AOP Sensor Suite as an assignable asset and the intent of NSF to provide research opportunities to the community for developing higher level AOP data products that were removed from the NEON project in 2015.

  17. Noble Gas-Uranium Coordination and Intersystem Crossing for the CUO(Ne)x(Ng)n (Ng = Ar, Kr, Xe) Complexes in Solid Neon

    SciTech Connect

    Andrews, Lester; Liang, Binyong; Li, Jun; Bursten, Bruce E.

    2004-02-15

    Atomic uranium excited by laser ablation reacts with CO in excess neon to produce the novel CUO molecule, which forms weak complexes CUO(Ne)m with neon and stronger complexes CUO(Ne)x(Ng)n (Ng = Ar, Kr, Xe) when the heavier noble gas atoms are present. The heavier CUO(Ne)m-1(Ng) complexes are identified through the effects of CO isotopic and Ng substitution on the neon matrix infrared spectra and by comparison to DFT frequency calculations on model complexes CUO(Ng) (Ng = Ne, Ar, Kr, Xe). The U-C and U-O stretching frequencies of CUO(Ne)m-1(Ng) complexes are slightly red shifted from 1047 and 872 cm-1 frequencies for the 1Sigma+ CUO ground state neon complex, which identifies singlet ground state CUO(Ne)m-1(Ng) complexes in solid neon. The next singlet CUO(Ne)x(Ng)2 complexes in excess neon follow in like manner. However, stretching modes and the isotopic shifts of the higher CUO(Ne)x(Ng)n complex approach those of the pure argon matrix CUO(Ar)n complex, which characterizes triple t ground state complexes by comparison to DFT frequency calculations.

  18. Recognizing Sequences of Sequences

    PubMed Central

    Kiebel, Stefan J.; von Kriegstein, Katharina; Daunizeau, Jean; Friston, Karl J.

    2009-01-01

    The brain's decoding of fast sensory streams is currently impossible to emulate, even approximately, with artificial agents. For example, robust speech recognition is relatively easy for humans but exceptionally difficult for artificial speech recognition systems. In this paper, we propose that recognition can be simplified with an internal model of how sensory input is generated, when formulated in a Bayesian framework. We show that a plausible candidate for an internal or generative model is a hierarchy of ‘stable heteroclinic channels’. This model describes continuous dynamics in the environment as a hierarchy of sequences, where slower sequences cause faster sequences. Under this model, online recognition corresponds to the dynamic decoding of causal sequences, giving a representation of the environment with predictive power on several timescales. We illustrate the ensuing decoding or recognition scheme using synthetic sequences of syllables, where syllables are sequences of phonemes and phonemes are sequences of sound-wave modulations. By presenting anomalous stimuli, we find that the resulting recognition dynamics disclose inference at multiple time scales and are reminiscent of neuronal dynamics seen in the real brain. PMID:19680429

  19. Carbonic anhydrase inhibitors. Inhibition of isozymes I, II, IV, V, and IX with anions isosteric and isoelectronic with sulfate, nitrate, and carbonate.

    PubMed

    Innocenti, Alessio; Vullo, Daniela; Scozzafava, Andrea; Supuran, Claudiu T

    2005-02-01

    The inhibition of five human carbonic anhydrase (hCA, EC 4.2.1.1) isozymes; the cytosolic hCA I and II, the membrane-bound hCA IV, the mitochondrial hCA V, and the tumor-associated, transmembrane hCA IX, with anions isosteric and isoelectronic with sulfate, nitrate, and carbonate; such as chlorate, perchlorate, bromate, iodate, periodate, silicate, bismuthate, vanadate, molybdate, and wolframate is reported. Apparently, the geometry of the inhibitor (tetrahedral or trigonal) does not influence its binding to the Zn(II) ion of the enzyme active site, but the nature of the central element is the most important factor influencing potency. Isozymes hCA I and II are best inhibited by chlorate, perchlorate, and silicate, together with the anions structurally related to sulfate, sulfamate, and sulfamidate, but sulfate itself is a weak inhibitor (inhibition constant of 74 mM against hCA I and 183 mM against hCA II). Molybdate is a very weak hCA I inhibitor (K(I) of 914 mM) but it interacts with hCA II (K(I) of 27.5mM). Isozyme IV is well inhibited by sulfate (K(I) of 9 mM), sulfamate, and sulfamidate (in the low micromolar range), but not by perchlorate (K(I) of 767 mM). The mitochondrial isozyme V has the lowest affinity for sulfate (K(I) of 680 mM) and carbonate (K(I) of 95 mM) among all the investigated isozymes, suggesting on one hand its possible participation in metabolon(s) with sulfate anion exchanger(s), and on the other hand an evolutionary adaptation to working at higher pH values (around 8.5 in mitochondria) where rather high amounts of carbonate in equilibrium with bicarbonate may be present. Metasilicate, isosteric to carbonate, is also about a 10 times weaker inhibitor of this isozyme as compared to other CAs investigated here (K(I) of 28.2 mM). Surprisingly, the tumor-associated isozyme IX is resistant to sulfate inhibition (K(I) of 154 mM) but has affinity in the low micromolar range for carbonate, sulfamate, and sulfamidate (K(I) in the range of 8

  20. Prediction of the thermophysical properties of pure neon, pure argon, and the binary mixtures neon-argon and argon-krypton by Monte Carlo simulation using ab initio potentials.

    PubMed

    Nasrabad, A E; Laghaei, R; Deiters, U K

    2004-10-01

    Gibbs ensemble Monte Carlo simulations were used to test the ability of intermolecular pair potentials derived ab initio from quantum mechanical principles, enhanced by Axilrod-Teller triple-dipole interactions, to predict the vapor-liquid phase equilibria of pure neon, pure argon, and the binary mixtures neon-argon and argon-krypton. The interaction potentials for Ne-Ne, Ar-Ar, Kr-Kr, and Ne-Ar were taken from literature; for Ar-Kr a different potential has been developed. In all cases the quantum mechanical calculations had been carried out with the coupled-cluster approach [CCSD(T) level of theory] and with correlation consistent basis sets; furthermore an extrapolation scheme had been applied to obtain the basis set limit of the interaction energies. The ab initio pair potentials as well as the thermodynamic data based on them are found to be in excellent agreement with experimental data; the only exception is neon. It is shown, however, that in this case the deviations can be quantitatively explained by quantum effects. The interaction potentials that have been developed permit quantitative predictions of high-pressure phase equilibria of noble-gas mixtures. (c) 2004 American Institute of Physics

  1. [The application of helium-neon laser radiation for the combined treatment of the patients with atrophic rhinitis].

    PubMed

    Sharipov, R A; Sharipova, E R

    2012-01-01

    The objective of the present study was to improve the efficacy of the treatment of the patients presenting with atrophic rhinitis (ozena) of the upper respiratory tract by the application of helium-neon laser radiation. A total of 120 patients aged from 15 to 53 years were treated based at the Department of Otorhinolaryngology, G.G. Kuvatov Republican Clinical Hospital, Ufa. All these patients underwent routine clinical, roentgenological, microbiological, and rheographic examination. The method for the treatment of atrophic rhinitis is described; it includes the application of helium-neon laser radiation in combination with the administration of the purified preparation of liquid polyvalent Klebsiella bacteriophage. The positive results of the treatment by the proposed method were documented in 90% of the patients.

  2. Computation of the properties of liquid neon, methane, and gas helium at low temperature by the Feynman-Hibbs approach.

    PubMed

    Tchouar, N; Ould-Kaddour, F; Levesque, D

    2004-10-15

    The properties of liquid methane, liquid neon, and gas helium are calculated at low temperatures over a large range of pressure from the classical molecular-dynamics simulations. The molecular interactions are represented by the Lennard-Jones pair potentials supplemented by quantum corrections following the Feynman-Hibbs approach. The equations of state, diffusion, and shear viscosity coefficients are determined for neon at 45 K, helium at 80 K, and methane at 110 K. A comparison is made with the existing experimental data and for thermodynamical quantities, with results computed from quantum numerical simulations when they are available. The theoretical variation of the viscosity coefficient with pressure is in good agreement with the experimental data when the quantum corrections are taken into account, thus reducing considerably the 60% discrepancy between the simulations and experiments in the absence of these corrections.

  3. Absorptions between 3000 and 5500 cm(-1) of cyclic O4+ and O4- trapped in solid neon.

    PubMed

    Jacox, Marilyn E; Thompson, Warren E

    2013-12-19

    Recently, gas-phase absorptions in the 3000-4300 cm(-1) spectral region have been assigned to combination bands built on (ν1 + ν5) of ground-state cyc-O4(+). Other gas-phase experiments identified an electronic transition of cyc-O4(-) complexed with an argon atom between 4000 and 5300 cm(-1). Absorptions that correspond closely to these two groups of bands have been observed in neon-matrix experiments in which both cyc-O4(+) and cyc-O4(-) are trapped at 4.3 K in solid neon. The results are compared with the gas-phase data, and the proposed assignments are considered by taking into account the results of isotopic substitution.

  4. Solar cosmic ray produced neon in lunar soils and their implication for gas-rich meteorite studies

    NASA Technical Reports Server (NTRS)

    Nautiyal, C. M.; Rao, M. N.

    1984-01-01

    Characteristic neon isotopic ratios, produced due to solar cosmic ray spallation (SCR) in lunar soils, are useful in deciphering and estimating the relative contributions of SCR and GCR spallation. To delineate these features, etched mineral grains from mature and immature lunar soils (14148 and 61221 respectively) were analyzed using mass spectrometry. The SF-Ne composition deduced in this work agrees with that obtained from earlier etched lunar pyroxene studies. The data points for mature soil 14148 define a line which significantly deviates from the 61221 tie line. This deviation is attributed to the presence of SCR spallation component. In this context, neon isotopic compositions (step-wise heating) in Pantar and Leighton dark portions were studied and compared with that of Fayetteville. The meteorite data points deviate significantly from the tie line joining SF-Ne and GCR (pyroxene) end points. This deviation is attributed to SCR-spallation in gas-rich chondrites.

  5. Effect of low-power helium-neon laser irradiation on 13-week immobilized articular cartilage of rabbits.

    PubMed

    Bayat, Mohammad; Ansari, Anayatallah; Hekmat, Hossien

    2004-09-01

    Influence of low-power (632.8 nm, Helium-Neon, 13 J/cm2, three times a week) laser on 13-week immobilized articular cartilage was examined with rabbits knee model. Number of chondrocytes and depth of articular cartilage of experimental group were significantly higher than those of sham irradiated group. Surface morphology of sham-irradiated group had rough prominences, fibrillation and lacunae but surface morphology of experimental group had more similarities to control group than to sham irradiated group. There were marked differences between ultrastructure features of control group and experimental group in comparison with sham irradiated group. Low-power Helium-Neon laser irradiation on 13-week immobilized knee joints of rabbits neutrilized adverse effects of immobilization on articular cartilage.

  6. Sensing earth's rotation with a helium-neon ring laser operating at 1.15  μm.

    PubMed

    Ulrich Schreiber, K; Thirkettle, Robert J; Hurst, Robert B; Follman, David; Cole, Garrett D; Aspelmeyer, Markus; Wells, Jon-Paul R

    2015-04-15

    We report on the operation of a 2.56  m2 helium-neon based ring laser interferometer at a wavelength of 1.152276 μm using crystalline coated intracavity supermirrors. This work represents the first implementation of crystalline coatings in an active laser system and expands the core application area of these low-thermal-noise cavity end mirrors to inertial sensing systems. Stable gyroscopic behavior can only be obtained with the addition of helium to the gain medium as this quenches the 1.152502 μm (2s4→2p7) transition of the neon doublet which otherwise gives rise to mode competition. For the first time at this wavelength, the ring laser is observed to readily unlock on the bias provided by the earth's rotation alone, yielding a Sagnac frequency of approximately 59 Hz.

  7. Branches of {sup 33}S(p,{gamma}){sup 34}Cl at oxygen-neon nova temperatures

    SciTech Connect

    Freeman, B. M.; Wrede, C.; Delbridge, B. G.; Garcia, A.; Knecht, A.; Sallaska, A. L.; Parikh, A.

    2011-04-15

    Recent simulations of classical novae on oxygen-neon white-dwarf stars indicate that the isotopic ratio {sup 32}S/{sup 33}S has the potential to be a remarkable indicator of presolar grains of nova origin. The {sup 33}S(p,{gamma}){sup 34}Cl reaction influences this ratio directly by destroying {sup 33}S in novae. Additionally, {beta}-delayed {gamma} rays from the metastable state of {sup 34}Cl (t{sub 1/2}=32 min) have been suggested to be potential nova observables. We have measured the branches for known {sup 33}S(p,{gamma}){sup 34}Cl resonances that are activated at temperatures relevant to oxygen-neon novae. We provide the first reliable uncertainties on these branches and the first upper limits for several previously unmeasured branches.

  8. Solid-state ring laser gyro behaving like its helium-neon counterpart at low rotation rates.

    PubMed

    Schwartz, Sylvain; Gutty, François; Feugnet, Gilles; Loil, Eric; Pocholle, Jean-Paul

    2009-12-15

    Nonlinear couplings induced by crystal diffusion and spatial inhomogeneities of the gain have been suppressed over a broad range of angular velocities in a solid-state ring laser gyro by vibrating the gain crystal at 168 kHz and 0.4 microm along the laser cavity axis. This device behaves in the same way as a typical helium-neon ring laser gyro, with a zone of frequency lock-in (or dead band) resulting from the backscattering of light on the cavity mirrors. Furthermore, it is shown that the level of angular random-walk noise in the presence of mechanical dithering depends only on the quality of the cavity mirrors, as is the case with typical helium-neon ring laser gyros.

  9. Generation of 12 fs deep-ultraviolet pulses by four-wave mixing through filamentation in neon gas.

    PubMed

    Fuji, Takao; Horio, Takuya; Suzuki, Toshinori

    2007-09-01

    Generation of deep-ultraviolet femtosecond pulses by four-wave mixing through filamentation in neon gas was demonstrated. Fundamental (omega) and second-harmonic (2omega) pulses of 25 fs Ti:sapphire amplifier output were focused into neon gas, and 20 microJ pulses with the center wavelength of 260 nm were produced by a four-wave mixing process, 2omega+2omega-omega?3omega through an ~15 cm filament. Additionally, pulses with an energy of 2 microJ at 200 nm were generated, probably by a cascaded process, 3omega+2omega-omega?4omega. The 260 nm pulses were compressed by a grating-based compressor and characterized by a dispersion-free transient grating frequency-resolved optical gating. The estimated pulse width was 12 fs.

  10. The neon content of nearby B-type stars and its implications for the solar model problem

    NASA Astrophysics Data System (ADS)

    Morel, T.; Butler, K.

    2008-08-01

    The recent downward revision of the solar photospheric abundances now leads to severe inconsistencies between the theoretical predictions for the internal structure of the Sun and the results of helioseismology. There have been claims that the solar neon abundance may be underestimated and that an increase in this poorly-known quantity could alleviate (or even completely solve) this problem. Early-type stars in the solar neighbourhood are well-suited to testing this hypothesis because they are the only stellar objects whose absolute neon abundance can be derived from the direct analysis of photospheric lines. Here we present a fully homogeneous NLTE abundance study of the optical Ne I and Ne II lines in a sample of 18 nearby, early B-type stars, which suggests log ɛ(Ne) = 7.97 ± 0.07 dex (on the scale in which log ɛ[H] = 12) for the present-day neon abundance of the local interstellar medium (ISM). Chemical evolution models of the Galaxy only predict a very small enrichment of the nearby interstellar gas in neon over the past 4.6 Gyr, implying that our estimate should be representative of the Sun at birth. Although higher by about 35% than the new recommended solar abundance, such a value appears insufficient by itself to restore the past agreement between the solar models and the helioseismological constraints. Appendices A and B are only available in electronic form at http://www.aanda.org Table [see full text] is also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/487/307

  11. Electron-helium and electron-neon scattering cross sections at low electron energies using a photoelectron source

    NASA Technical Reports Server (NTRS)

    Kumar, Vijay; Subramanian, K. P.; Krishnakumar, E.

    1987-01-01

    Absolute electron-helium and electron-neon scattering cross sections have been measured at low electron energies using the powerful technique of photoelectron spectroscopy. The measurements have been carried out at 17 electron energies varying from 0.7 to 10 eV with an accuracy of + or - 2.7 percent. The results obtained in the present work have been compared with other recent measurement and calculations.

  12. Investigation of the stability of the emission wavelength of a laser with an external neon absorption cell

    SciTech Connect

    Kapralov, V.P.; Privalov, V.E.; Chulyaeva, E.G.

    1980-08-01

    The optical heterodyne method was used to determine the absolute wavelength of a commercial LG-149-1 helium--neon laser. Measurements were carried out using apparatus containing a laser stabilized by the saturated absorption in /sup 127/I, which acted as the reference source. The iodine laser wavelength was determined interferrometrically by comparison with the wavelength of the orange line of /sup 86/Kr.

  13. Laser-based measurement of transition probabilities of neon 2p 53s-2p 53p transitions

    NASA Astrophysics Data System (ADS)

    Fujimoto, Takashi; Goto, Chiaki; Uetani, Yasunori; Fukuda, Kuniya

    1985-01-01

    By using the magic-angle, pulsed-excitation method in the presence of a magnetic field, the authors have measured the branching ratios for 2p 53s-2p 53p transitions in neon. By combining values for the lifetime of the upper levels with the branching ratios, they have determined the transition probabilities of 31 transitions. The results are in good agreement with those from emission spectroscopy of a high-pressure are plasma by Bridges and Wiese.

  14. Observations and simulations of Nova Vul 1984 No. 2: A nova with ejecta rich in oxygen, neon, and magnesium

    SciTech Connect

    Starrfield, S.; Sonneborn, G.; Stryker, L.L.; Sparks, W.M.; Truran, J.W.; Ferland, G.; Wagner, R.M.; Gallagher, J.S.; Wade, R.; Williams, R.E.; Kenyon, S.; Shaviv, G.; Wu, C.C.; Gehrz, R.D.; Ney, E.P.

    1988-01-01

    Nova Vul 1984 /number sign/2 has been observed with the IUE Satellite from December 1984 through November 1987 and we expect to be able to observe it with the IUE Satellite for at least another two years. These spectra are characterized by strong lines from Mg, Ne, C, Si, O, N, and other elements. Data obtained in the ultraviolet, infrared, and optical show that this nova is ejecting material rich in oxygen, neon, and magnesium. 16 refs., 5 figs., 1 tab.

  15. Electron-helium and electron-neon scattering cross sections at low electron energies using a photoelectron source

    NASA Technical Reports Server (NTRS)

    Kumar, Vijay; Subramanian, K. P.; Krishnakumar, E.

    1987-01-01

    Absolute electron-helium and electron-neon scattering cross sections have been measured at low electron energies using the powerful technique of photoelectron spectroscopy. The measurements have been carried out at 17 electron energies varying from 0.7 to 10 eV with an accuracy of + or - 2.7 percent. The results obtained in the present work have been compared with other recent measurement and calculations.

  16. Effect of helium-neon laser on fast excitatory postsynaptic potential of neurons in the isolated rat superior cervical ganglia

    NASA Astrophysics Data System (ADS)

    Mo, Hua; He, Ping; Mo, Ning

    2004-08-01

    The aim of this study is to further measure the effect of 632.8-nm helium-neon laser on fast excitatory postsynaptic potential (f-EPSP) of postganglionic neurons in isolated rat superior cervical ganglia by means of intracellular recording techniques. The neurons with f-EPSP were irradiated by different power densities (1-5 mW/cm2) laser. Irradiated by the 2-mW/cm2 laser, the amplitude of the f-EPSP could augment (P<0.05, paired t test) and even cause action potential at the end of the first 1-2 minutes, the f-EPSP could descend and last for 3-8 minutes. But the amplitude of the f-EPSP of neurons irradiated by the 5-mW/cm2 laser could depress for the irradiating periods. The results show that: 1) the variation of the amplitude of f-EPSP caused by laser is power density-dependent and time-dependent; 2) there exist the second-order phases in the interaction of the helium-neon laser with neurons. These findings may provide certain evidence in explanation of the mechanisms of clinical helium-neon laser therapy.

  17. Infrared spectra and electronic structure calculations for NN complexes with U, UN, and NUN in solid argon, neon, and nitrogen.

    PubMed

    Andrews, Lester; Wang, Xuefeng; Gong, Yu; Kushto, Gary P; Vlaisavljevich, Bess; Gagliardi, Laura

    2014-07-17

    Reactions of laser-ablated U atoms with N2 molecules upon codeposition in excess argon or neon at 4 K gave intense NUN and weak UN absorptions. Annealing produced progressions of new absorptions for the UN2(N2)1,2,3,4,5 and UN(N2)1,2,3,4,5,6 complexes. The neon-to-argon matrix shift decreases with increasing NN ligation and therefore the number of noble gas atoms left in the primary coordination sphere around the NUN molecule. Small matrix shifts are observed when the secondary coordination layers around the primary UN2(N2)1,2,3,4,5 and UN(N2)1,2,3,4,5,6 complexes are changed from neon-to-argon to nitrogen. Electronic structure, energy, and frequency calculations provide support for the identification of these complexes and the characterization of the N≡U≡N and U≡N core molecules as terminal uranium nitrides. Codeposition of U with pure nitrogen produced the saturated U(NN)7 complex, which UV irradiation converted to the NUN(NN)5 complex with slightly lower frequencies than found in solid argon.

  18. Mapping the phase diagram for neon to a quantum Lennard-Jones fluid using Gibbs ensemble simulations.

    PubMed

    Georgescu, Ionuţ; Brown, Sandra E; Mandelshtam, Vladimir A

    2013-04-07

    In order to address the issue of whether neon liquid in coexistence with its gas phase can be mapped to a quantum Lennard-Jones (LJ) fluid, we perform a series of simulations using Gibbs ensemble Monte Carlo for a range of de Boer quantum parameters Λ=ℏ/(σ√(mε)). The quantum effects are incorporated by implementing the variational gaussian wavepacket method, which provides an efficient numerical framework for estimating the quantum density at thermal equilibrium. The computed data for the LJ liquid is used to produce its phase diagram as a function of the quantum parameter, 0.065 ≤ Λ ≤ 0.11. These data are then used to fit the experimental phase diagram for neon liquid. The resulting parameters, ε = 35.68 ± 0.03 K and σ = 2.7616 ± 0.0005 Å (Λ = 0.0940), of the LJ pair potential are optimized to best represent liquid neon in coexistence with its gas phase for a range of physically relevant temperatures. This multi-temperature approach towards fitting and assessing a pair-potential is much more consistent than merely fitting a single data point, such as a melting temperature or a second virial coefficient.

  19. The Biological Effectiveness of Four Energies of Neon Ions for the Induction of Chromosome Damage in Human Lymphocytes

    NASA Technical Reports Server (NTRS)

    George, Kerry; Hada, Megumi; Cucinotta, F. A.

    2011-01-01

    Chromosomal aberrations were measured in human peripheral blood lymphocytes after in vitro exposure to neon ions at energies of 64, 89, 142, or 267. The corresponding LET values for these energies of neon ranged from 38-103 keV/micrometers and doses delivered were in the 10 to 80 cGy range. Chromosome exchanges were assessed in metaphase and G2 phase cells at first division after exposure using fluorescence in situ hybridization (FISH) with whole chromosome probes and dose response curves were generated for different types of chromosomal exchanges. The yields of total chromosome exchanges were similar for the 64, 89, and 142 MeV exposures, whereas the 267 MeV/u neon with LET of 38 keV/micrometers produced about half as many exchanges per unit dose. The induction of complex type chromosome exchanges (exchanges involving three or more breaks and two or more chromosomes) showed a clear LET dependence for all energies. The ratio of simple to complex type exchanges increased with LET from 18 to 51%. The relative biological effectiveness (RBE) was estimated from the initial slope of the dose response curve for chromosome damage with respect to gamma-rays. The RBE(sub max) values for total chromosome exchanges for the 64 MeV/u was around 30.

  20. Direct Test of the Role of E× B Shear in Improved Confinement with Neon Injection Using Magnetic Braking

    NASA Astrophysics Data System (ADS)

    Ernst, D. R.; Murakami, M.; La Haye, R. J.; Jackson, G. L.; Burrell, K. H.; Evans, T. E.; Greenfield, C. M.; West, W. P.; McKee, G. R.; Rettig, C. L.

    2000-10-01

    We have conducted experiments using magnetic braking to independently control E_r~= V_tor Bp in L-mode plasmas with neon injection. These experiments directly test the theory [D.R. Ernst, IAEA 1998, v. 2 p. 741.] that E× B shear, together with the suppression of turbulence by impurities, gives rise to strong improvements observed in the ion-channel, which more than double the ion temperature. Previous DIII-D experiments have measured reduced fluctuation levels with neon injection together with increased E× B shear [G.R. McKee, Phys. Plasmas 7, 1870 (2000)]. Our results show specifically that as magnetic braking independently slows toroidal rotation, ion temperature and total stored energy decrease monotonically with the braking torque, with no effect on density or MHD activity. The braking has little effect without neon, apart from perhaps delaying H-mode onset.

  1. Infrared spectra of ClCN{sup +}, ClNC{sup +}, and BrCN{sup +} trapped in solid neon

    SciTech Connect

    Jacox, Marilyn E.; Thompson, Warren E.

    2007-06-28

    When a mixture of ClCN or BrCN with a large excess of neon is codeposited at 4.3 K with a beam of neon atoms that have been excited in a microwave discharge, the infrared spectrum of the resulting solid includes prominent absorptions of the uncharged isocyanide, ClNC or BrNC, and of the corresponding cation, ClCN{sup +} or BrCN{sup +}. The NC-stretching fundamentals of the isocyanides trapped in solid neon lie close to the positions for their previously reported argon-matrix counterparts. The CN-stretching absorptions of ClCN{sup +} and BrCN{sup +} and the CCl-stretching absorption of ClCN{sup +} appear very close to the gas-phase band centers. Absorptions of two overtones and one combination band of ClCN{sup +} are identified. Reversible photoisomerization of ClCN{sup +} to ClNC{sup +} occurs. The two stretching vibrational fundamentals and several infrared and near infrared absorptions associated with electronic transitions of ClNC{sup +} are observed. Minor infrared peaks are attributed to the vibrational fundamental absorptions of the CX and CX{sup +} species (X=Cl,Br)

  2. Structural analysis of the bright monomeric yellow-green fluorescent protein mNeonGreen obtained by directed evolution.

    PubMed

    Clavel, Damien; Gotthard, Guillaume; von Stetten, David; De Sanctis, Daniele; Pasquier, Hélène; Lambert, Gerard G; Shaner, Nathan C; Royant, Antoine

    2016-12-01

    Until recently, genes coding for homologues of the autofluorescent protein GFP had only been identified in marine organisms from the phyla Cnidaria and Arthropoda. New fluorescent-protein genes have now been found in the phylum Chordata, coding for particularly bright oligomeric fluorescent proteins such as the tetrameric yellow fluorescent protein lanYFP from Branchiostoma lanceolatum. A successful monomerization attempt led to the development of the bright yellow-green fluorescent protein mNeonGreen. The structures of lanYFP and mNeonGreen have been determined and compared in order to rationalize the directed evolution process leading from a bright, tetrameric to a still bright, monomeric fluorescent protein. An unusual discolouration of crystals of mNeonGreen was observed after X-ray data collection, which was investigated using a combination of X-ray crystallography and UV-visible absorption and Raman spectroscopies, revealing the effects of specific radiation damage in the chromophore cavity. It is shown that X-rays rapidly lead to the protonation of the phenolate O atom of the chromophore and to the loss of its planarity at the methylene bridge.

  3. Effect of low-level helium-neon laser therapy on histological and ultrastructural features of immobilized rabbit articular cartilage.

    PubMed

    Bayat, Mohammad; Ansari, Enayatallah; Gholami, Narges; Bayat, Aghdas

    2007-05-25

    The present study investigates whether low-level helium-neon laser therapy can increase histological parameters of immobilized articular cartilage in rabbits or not. Twenty five rabbits were divided into three groups: the experiment group, which received low-level helium-neon laser therapy with 13J/cm(2) three times a week after immobilization of their right knees; the control group which did not receive laser therapy after immobilization of their knees; and the normal group which received neither immobilization nor laser therapy. Histological and electron microscopic examinations were performed at 4 and 7 weeks after immobilization. Depth of the chondrocyte filopodia in four-week immobilized experiment group, and depth of articular cartilage in seven-week immobilized experiment group were significantly higher than those of relevant control groups (exact Fisher test, p=0.001; student's t-test, p=0.031, respectively). The surfaces of articular cartilages of the experiment group were relatively smooth, while those of the control group were unsmooth. It is therefore concluded that low-level helium-neon laser therapy had significantly increased the depth of the chondrocyte filopodia in four-week immobilized femoral articular cartilage and the depth of articular cartilage in seven-week immobilized knee in comparison with control immobilized articular cartilage.

  4. Investigation of the statistical nature and structure of the electrical breakdown time delay in gas diodes filled with neon

    SciTech Connect

    Maluckov, Cedomir A.; Karamarkovic, Jugoslav P.; Radovic, Miodrag K.

    2006-12-01

    The electrical breakdown time delay in gas diodes filled by neon at the low pressures is investigated experimentally and theoretically. Experimental results are obtained measuring the characteristics of gas diodes filled by spectroscopically pure neon. In order to discard any systematic trend during the measurement procedure, checking of the measured values randomness preceded the statistical analysis of the experimental results. Novel theoretical model is established for interpretation of obtained experimental results on the breakdown time delay. The model is based on the assumptions of the exponential distribution of the statistical time delay and Gaussian distribution of the formative discharge time. Therefore, the density distribution of the breakdown time delay is assumed to be convolution of the statistical and formative time delay distributions. Parameters of the statistical and formative time delay, as stochastic variables, are modeled by the numerical Monte Carlo method. Numerical distributions are tested to the corresponding experimental distributions of the breakdown time delay by varying the distribution parameters. In addition, the asymmetry coefficient and skewness coefficient of the breakdown time delay distribution, and coefficients of the statistical and formative time delay distributions are analyzed. Numerically calculated time delay distributions fit well to the corresponding experimental distributions in gas diodes filled with neon at low pressures.

  5. Challenges and Opportunities to Developing Synergies Among Diverse Environmental Observatories: FSML, NEON, and GLEON

    NASA Astrophysics Data System (ADS)

    Williamson, C. E.; Weathers, K. C.; Knoll, L. B.; Brentrup, J.

    2012-12-01

    Recent rapid advances in sensor technology and cyberinfrastructure have enabled the development of numerous environmental observatories ranging from local networks at field stations and marine laboratories (FSML) to continental scale observatories such as the National Ecological Observatory Network (NEON) to global scale observatories such as the Global Lake Ecological Observatory Network (GLEON). While divergent goals underlie the initial development of these observatories, and they are often designed to serve different communities, many opportunities for synergies exist. In addition, the use of existing infrastructure may enhance the cost-effectiveness of building and maintaining large scale observatories. For example, FSMLs are established facilities with the staff and infrastructure to host sensor nodes of larger networks. Many field stations have existing staff and long-term databases as well as smaller sensor networks that are the product of a single or small group of investigators with a unique data management system embedded in a local or regional community. These field station based facilities and data are a potentially untapped gold mine for larger continental and global scale observatories; common ecological and environmental challenges centered on understanding the impacts of changing climate, land use, and invasive species often underlie these efforts. The purpose of this talk is to stimulate a dialog on the challenges of merging efforts across these different spatial and temporal scales, as well as addressing how to develop synergies among observatory networks with divergent roots and philosophical approaches. For example, FSMLs have existing long-term databases and facilities, while NEON has sparse past data but a well-developed template and closely coordinated team working in a coherent format across a continental scale. GLEON on the other hand is a grass-roots network of experts in science, information technology, and engineering with a common goal

  6. Spatial fractionation of the dose using neon and heavier ions: A Monte Carlo study.

    PubMed

    Peucelle, C; Martínez-Rovira, I; Prezado, Y

    2015-10-01

    This work explores a new radiation therapy approach which might trigger a renewed use of neon and heavier ions to treat cancers. These ions were shown to be extremely efficient in radioresistant tumor killing. Unfortunately, the efficient region also extends into the normal tissue in front of the tumor. The strategy the authors propose is to profit from the well-established sparing effect of thin spatially fractionated beams, so that the impact on normal tissues might be minimized while a high tumor control is achieved. The main goal of this work is to provide a proof of concept of this new approach. With that aim, a dosimetric study was carried out as a first step to evaluate the interest of further explorations of this avenue. The gate/geant4 v.6.1 Monte Carlo simulation platform was employed to simulate arrays of rectangular minibeams (700 μm × 2 cm) of four ions (Ne, Si, Ar, and Fe). The irradiations were performed with a 2 cm-long spread-out Bragg peak centered at 7 cm-depth. Dose distributions in a water phantom were scored considering two minibeams center-to-center distances: 1400 and 3500 μm. Peak and valley doses, peak-to-valley dose ratios (PVDRs), beam penumbras, and relative contribution of nuclear fragments and electromagnetic processes were assessed as figures of merit. In addition, the type and proportion of the secondary nuclear fragments were evaluated in both peak and valley regions. Extremely high PVDR values (>100) and low valley doses were obtained. The higher the atomic number (Z) of the primary ion is, the lower the valleys and the narrower the penumbras. Although the yield of secondary nuclear products increases with Z, the actual dose being deposited by the secondary nuclear fragments in the valleys starts to be the dominant contribution at deeper points, helping in the sparing of proximal normal tissues. Additionally, a wider center-to-center distance leads to a minimized contribution of heavier secondary fragments in valleys. The

  7. Sensitivity of the NEON Imaging Spectrometer Data Products to Cloud Conditions and Solar Illumination Geometry

    NASA Astrophysics Data System (ADS)

    Leisso, N.

    2016-12-01

    The National Ecological Observatory Network is a continental-scale ecological observatory funded by the NSF to collect and disseminate ecological data. NEON consists of standardized terrestrial, instrumental, and aquatic observation systems in addition to an airborne remote sensing component. The Airborne Observation Platform (AOP) group operates a payload of sensors including a waveform LiDAR, imaging spectrometer (NIS) and an RGB camera. To support the NEON project, three payloads are intended to annually acquire data over sites distributed throughout the United States in 20 individual eco-climatic regions during periods of vegetative peak greenness. The NIS is a push-broom visible to shortwave infrared (VSWIR) spectrometer (380 to 2500 nm) designed by NASA JPL for ecological applications. The NIS collects data at 5 nm spectral intervals with approximately 600 spatial pixels covering a 34-degree Field-of View. At the nominal operational flight altitude of 1000 m, the 1 mRad IFOV allows development of surface reflectance and higher-level data products at 1 m spatial resolution. Two of the primary operational constraints prohibiting accurate surface reflectance retrievals from the NIS, are 1) sufficiently clear cloud conditions and 2) sufficiently high solar zenith angles. To understand the limitations of the NIS and the quality of the derived data products under these constraints, a sensitivity analysis was undertaken which consisted of repeated NIS acquisitions with North-South and East-West flight lines over a consistent vegetated target area at Table Mountain, Colorado. Several flights were conducted as solar zenith angles varied from 20° to 70° and during clear and varying cloud conditions. During the acquisition, validation data in the form of field spectrometer measurements were acquired over two tarps of nominal 3% and 48% spectral reflectance, as well as of vegetation and gravel roadways within the target collection area. Results from the analysis showed

  8. Absolute Differential Scattering Cross-Sections of Electrons from Neon, Nitrogen and Methyl Chloride

    NASA Astrophysics Data System (ADS)

    Shi, Xueying

    The relative flow technique is used to obtain absolute DCS in a crossed-beam experiment. A novel gas handling system was designed to facilitate these measurements. The absolute DCS of electrons scattered from neon have been measured from 7 eV down to 0.25 eV. At energies of 2 eV and lower, our results are in excellent agreement with MERT and recent ab initio calculation. At energies higher than 2 eV, our results are in excellent agreement with those of Williams. Thus we propose that neon can be used as a benchmark to test the overall performance of the electron spectrometer at low energies. The angular dependence of absolute vibrationally -elastic DCS of electrons scattered from N_2 have been measured at 0.55 eV, 1.50 eV, and ~2.22 eV, the second elastic peak of the ^2Pi_{rm g} resonance. Our results at these two lower energies are much larger than the previous experimental results, but in close agreement with theoretical calculations by Morrison. By extrapolating our curves to 0^ circ and 180^circ using Morrison's curves as a guide, integration gave the total vibrationally-elastic cross sections at these two energies. Our results are within 2-4% of the experimentally measured total cross sections. Methyl Chloride is the simplest saturated hydrocarbon with a single chlorine atom substitution. Two resonances have been assigned in CH_3Cl, the a_1(C-Cl,sigma^*) resonance at 3.45 eV and the e(C-H,sigma ^*) resonance at 5.5 eV. In the elastic channel, the measurements show that dipole scattering dominates at low energies and in the forward direction. In inelastic channels, the C-Cl stretch mode nu_3(a _1) is strongly excited by the sigma ^*(C-Cl) shape resonance, and the C-H stretch mode nu_4(e) is the strongest one excited by the e resonance. The angular dependences for excitation of these two modes are relatively flat. The shapes cannot be explained solely by a few leading terms in the angular momentum expansion arising from the resonance. This suggests that non

  9. Spatial fractionation of the dose using neon and heavier ions: A Monte Carlo study

    SciTech Connect

    Peucelle, C.; Martínez-Rovira, I.; Prezado, Y.

    2015-10-15

    Purpose: This work explores a new radiation therapy approach which might trigger a renewed use of neon and heavier ions to treat cancers. These ions were shown to be extremely efficient in radioresistant tumor killing. Unfortunately, the efficient region also extends into the normal tissue in front of the tumor. The strategy the authors propose is to profit from the well-established sparing effect of thin spatially fractionated beams, so that the impact on normal tissues might be minimized while a high tumor control is achieved. The main goal of this work is to provide a proof of concept of this new approach. With that aim, a dosimetric study was carried out as a first step to evaluate the interest of further explorations of this avenue. Methods: The GATE/GEANT4 v.6.1 Monte Carlo simulation platform was employed to simulate arrays of rectangular minibeams (700 μm × 2 cm) of four ions (Ne, Si, Ar, and Fe). The irradiations were performed with a 2 cm-long spread-out Bragg peak centered at 7 cm-depth. Dose distributions in a water phantom were scored considering two minibeams center-to-center distances: 1400 and 3500 μm. Peak and valley doses, peak-to-valley dose ratios (PVDRs), beam penumbras, and relative contribution of nuclear fragments and electromagnetic processes were assessed as figures of merit. In addition, the type and proportion of the secondary nuclear fragments were evaluated in both peak and valley regions. Results: Extremely high PVDR values (>100) and low valley doses were obtained. The higher the atomic number (Z) of the primary ion is, the lower the valleys and the narrower the penumbras. Although the yield of secondary nuclear products increases with Z, the actual dose being deposited by the secondary nuclear fragments in the valleys starts to be the dominant contribution at deeper points, helping in the sparing of proximal normal tissues. Additionally, a wider center-to-center distance leads to a minimized contribution of heavier secondary

  10. [Trace elements in the statoliths of neon flying squid, Ommastrephes bartramii in the Northwest Pacific Ocean].

    PubMed

    Lu, Hua-Jie; Chen, Xin-Jun; Ma, Jin

    2014-08-01

    Statolith is one of the most important hard tissues of cephalopods which is widely used in the research of fisheries ecology including population structure, life history reconstruction and so on. Trace elements of 18 statoliths of neon flying squid Ommastrephes bartramii collected in the Northwest Pacific Ocean in 2007 by Chinese jigging fishing fleets were analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The results indicated that the statoliths of O. bartramii mainly contained 55 elements, and calcium (Ca), strontium (Sr), sodium (Na), phosphorus (P), potassium (K), silicon (Si), magnesium (Mg), boron (B), iron (Fe), barium (Ba) were the 10 most abundant elements. The analysis of variance showed that there was no significant difference in each element distribution between different sexual squid except for P, Si and B. Significant differences existed in the contents of Sr and Na but no significant difference was found in the contents of Ca, P, K, Si, Mg, B, Fe and Ba between different hatching populations. There were significant differences in the contents of Ca, Sr, Na, P, Mg and Ba, but no significant difference was found in the contents of K, Fe, B and Si in the statoliths among different growth zones. This study presented Sr and Na could be the best two trace elements used in the research on the population structure and life history reconstruction for O. bartramii.

  11. Effect of helium-neon and infrared laser irradiation on wound healing in rabbits

    SciTech Connect

    Braverman, B.; McCarthy, R.J.; Ivankovich, A.D.; Forde, D.E.; Overfield, M.; Bapna, M.S.

    1989-01-01

    We examined the biostimulating effects of helium-neon laser radiation (HeNe; 632.8 nm), pulsed infrared laser radiation (IR; 904 nm), and the two combined on skin wound healing in New Zealand white rabbits. Seventy-two rabbits received either (1) no exposure, (2) 1.65 J/cm2 HeNe, (3) 8.25 J/cm2 pulsed IR, or (4) both HeNe and IR together to one of two dorsal full-thickness skin wounds, daily, for 21 days. Wound areas were measured photographically at periodic intervals. Tissue samples were analyzed for tensile strength, and histology was done to measure epidermal thickness and cross-sectional collagen area. Significant differences were found in the tensile strength of all laser-treated groups (both the irradiated and nonirradiated lesion) compared to group 1. No differences were found in the rate of wound healing or collagen area. Epidermal growth was greater in the HeNe-lased area compared to unexposed tissue, but the difference was not significant. Thus, laser irradiation at 632.8 nm and 904 nm alone or in combination increased tensile strength during wound healing and may have released tissue factors into the systemic circulation that increased tensile strength on the opposite side as well.

  12. Light noble gas chemistry: Structures, stabilities, and bonding of helium, neon and argon compounds

    SciTech Connect

    Frenking, G. ); Koch, W. ); Reichel, F. ); Cremer, D. )

    1990-05-23

    Theoretically determined geometries are reported for the light noble gas ions Ng{sub 2}C{sup 2+}, Ng{sub 2}N{sup 2+}, Ng{sub 2}O{sup 2+}, NgCCNg{sup 2+}, NgCCH{sup +}, NgCN{sup +}, and NgNC{sup +} (Ng = He, Ne, Ar) at the MP2/6-31G(d,p) level of theory. In a few cases, optimizations were carried out at CASSCF/6-31G(d,p). The thermodynamic stability of the Ng compounds is investigated at MP4(SDTQ)/6-311G(2df,2pd) for Ng = He, Ne and at MP4(SDTQ)/6-311G(d,p) for Ng = Ar. The structures and stabilities of the molecules are discussed in terms of donor-acceptor interactions between Ng and the respective fragment cation, by using molecular orbital arguments and utilizing the analysis of the electron density distribution and its associated Laplace field. Generally, there is an increase in Ng,X binding interactions of a noble gas molecule NgX with increasing atomic size of Ng. In some cases the Ne,X stabilization energies are slightly smaller than the corresponding He,X values because of repulsive p-{pi} interactions in the neon compounds. The argon molecules are in all cases significantly stronger bound.

  13. Short wavelength laser calculations for electron pumping in neon-like krypton (Kr XXVII)

    NASA Technical Reports Server (NTRS)

    Feldman, U.; Bhatia, A. K.; Suckewer, S.

    1983-01-01

    Calculations of electron impact collision strengths and spontaneous radiative decay rates are made for neon-like krypton (Kr XXVII) for the 2s2 2p6, 2s2 2p5 3s, 2s2 2p5 3p, and 2s2 2p5 3d configurations. From these atomic data, the level populations as a function of the electron density are calculated at two temperatures, 1 x 10 to the 7th K and 3 x 10 to the 7th K. An analysis of level populations reveals that a volume of krypton in which a significant number of the ions are in the Kr XXVII degree of ionization can produce a significant gain in transition between the 2s2 2p5 3s and 2s2 2p5 3p configurations. At an electron density of 1 x 10 to the 19th/cu cm the plasma length has to be of the order of 1 m; at a density of 1 x 10 to the 21st/cu cm the length is reduced to approximately 0.5 cm; and at an electron density of 1 x 10 to the 22nd/cu cm the length of the plasma is further reduced to approximately 1 mm.

  14. Molecular simulation of the thermodynamic, structural, and vapor-liquid equilibrium properties of neon

    NASA Astrophysics Data System (ADS)

    Vlasiuk, Maryna; Frascoli, Federico; Sadus, Richard J.

    2016-09-01

    The thermodynamic, structural, and vapor-liquid equilibrium properties of neon are comprehensively studied using ab initio, empirical, and semi-classical intermolecular potentials and classical Monte Carlo simulations. Path integral Monte Carlo simulations for isochoric heat capacity and structural properties are also reported for two empirical potentials and one ab initio potential. The isobaric and isochoric heat capacities, thermal expansion coefficient, thermal pressure coefficient, isothermal and adiabatic compressibilities, Joule-Thomson coefficient, and the speed of sound are reported and compared with experimental data for the entire range of liquid densities from the triple point to the critical point. Lustig's thermodynamic approach is formally extended for temperature-dependent intermolecular potentials. Quantum effects are incorporated using the Feynman-Hibbs quantum correction, which results in significant improvement in the accuracy of predicted thermodynamic properties. The new Feynman-Hibbs version of the Hellmann-Bich-Vogel potential predicts the isochoric heat capacity to an accuracy of 1.4% over the entire range of liquid densities. It also predicts other thermodynamic properties more accurately than alternative intermolecular potentials.

  15. CO2-helium and CO2-neon mixtures at high pressures

    NASA Astrophysics Data System (ADS)

    Mallick, B.; Ninet, S.; Le Marchand, G.; Munsch, P.; Datchi, F.

    2013-01-01

    The properties of mixtures of carbon dioxide with helium or neon have been investigated as a function of CO2 concentration and pressure up to 30 GPa at room temperature. The binary phase diagrams of these mixtures are determined over the full range of CO2 concentrations using visual observations and Raman scattering measurements. Both diagrams are of eutectic type, with a fluid-fluid miscibility gap for CO2 concentrations in the range [5, 75] mol. % for He and [8, 55] mol. % for Ne, and a complete separation between the two components in the solid phase. The absence of alloys or stoichiometric compounds for these two binary systems is consistent with the Hume-Rothery rules of hard sphere mixtures. The Raman spectra and x-ray diffraction patterns of solid CO2 embedded in He or Ne for various initial concentrations have been measured up to 30 GPa and 12 GPa, respectively. The frequencies of the Raman modes and the volume of solid phase I are identical, within error bars, to those reported for 100% CO2 samples, thus confirming the total immiscibility of CO2 with He and Ne in the solid phase. These results demonstrate the possibility to perform high-pressure experiments on solid CO2 under (quasi-)hydrostatic conditions using He or Ne as pressure transmitting medium.

  16. Characteristics of capacitively coupled RF helium/neon discharges in a hollow fiber

    NASA Astrophysics Data System (ADS)

    Duan, Lian; Wang, Xinbing; Zuo, Duluo

    2016-11-01

    Capacitively coupled radio-frequency microplasmas are produced in hollow fibers with an inner diameter of hundreds of micrometers powered by an 80-MHz power supply. Considering the narrow space of the hollow core, optical emission spectrometry is used to obtain the spatially resolved characteristics of the microplasmas. The rotational temperature, excitation temperature, and electron density of microplasmas are determined based on the second positive band of nitrogen, the atomic spectra of bulk neutral particles of plasmas, and the Hβ line of the hydrogen Balmer series, respectively. In our experiments, the rotational temperature, excitation temperature, and electron density of typical inert gases helium and neon are in the ranges of 300-500 K, 7000-9500 K, and 1013 cm-3, respectively. The results obtained with different external parameters of power and pressure show that the light emission intensity increases with power and pressure. The distributions of the rotational temperature, excitation temperature, and electron density of the microplasmas are almost constant over the gap between the electrodes. These distributions are mostly insensitive to the change of power and pressure in single-component plasmas. The characteristics of mixed plasmas are also investigated. The plasma with a larger helium content possesses higher excitation temperature and lower rotational temperature and electron density than those of the plasma with a lower helium content.

  17. Molecular simulation of the thermodynamic, structural, and vapor-liquid equilibrium properties of neon.

    PubMed

    Vlasiuk, Maryna; Frascoli, Federico; Sadus, Richard J

    2016-09-14

    The thermodynamic, structural, and vapor-liquid equilibrium properties of neon are comprehensively studied using ab initio, empirical, and semi-classical intermolecular potentials and classical Monte Carlo simulations. Path integral Monte Carlo simulations for isochoric heat capacity and structural properties are also reported for two empirical potentials and one ab initio potential. The isobaric and isochoric heat capacities, thermal expansion coefficient, thermal pressure coefficient, isothermal and adiabatic compressibilities, Joule-Thomson coefficient, and the speed of sound are reported and compared with experimental data for the entire range of liquid densities from the triple point to the critical point. Lustig's thermodynamic approach is formally extended for temperature-dependent intermolecular potentials. Quantum effects are incorporated using the Feynman-Hibbs quantum correction, which results in significant improvement in the accuracy of predicted thermodynamic properties. The new Feynman-Hibbs version of the Hellmann-Bich-Vogel potential predicts the isochoric heat capacity to an accuracy of 1.4% over the entire range of liquid densities. It also predicts other thermodynamic properties more accurately than alternative intermolecular potentials.

  18. Design and experimental investigation of a neon cryogenic loop heat pipe

    NASA Astrophysics Data System (ADS)

    He, Jiang; Guo, Yuandong; Zhang, Hongxing; Miao, Jianyin; Wang, Lu; Lin, Guiping

    2017-03-01

    Next generation space infrared sensor and detector have pressing requirement for cryogenic heat transport technology in the temperature range of 30-40 K. Cryogenic loop heat pipe (CLHP) has excellent thermal performance and particular characteristics such as high flexibility transport lines and no moving parts, thus it is regarded as an ideal thermal control solution. A neon CLHP referring to infrared point-to-point heat transfer element in future space application has been designed and experimented. And it could realize supercritical startup successfully. Experimental results show that the supercritical startup were realized successfully at cases of 1.5 W secondary evaporator power, but the startup was failed when 0.5 and 1 W heat load applied to secondary evaporator. The maximum heat transport capability of primary evaporator is between 4.5 and 5 W with proper auxiliary heat load. Before startup, even the heat sink temperature decreased to 35 K, the primary evaporator can still maintain at almost 290 K; and the primary evaporator temperature increased at once when the powers were cut off, which indicated the CLHP has a perfect function of thermal switch. The CLHP could adapt to sudden changes of the primary evaporator power, and reach a new steady-state quickly. Besides, some failure phenomena were observed during the test, which indicated that proper secondary evaporator power and heat sink temperature play important roles on the normal operation.

  19. Using Gamma-Ray Line Observations to Determine the Chromospheric Neon/Oxygen Abundance Ratio

    NASA Astrophysics Data System (ADS)

    Share, Gerald H.; Murphy, R.

    2009-05-01

    There has been a lively debate concerning the solar neon abundance since Asplund et al. (2005) reported a significant downward revision of C, N, and O abundances from those compiled by Grevesse and Sauval (1998). This lower metallicity has affected solar opacity to the extent that solar interior models are no longer consistent with helioseismology data. As Ne is not measured directly in the photosphere, Bahcall et al. (2005) have suggested that a solar Ne abundance a factor of 3 higher than the adopted value (Ne/O 0.15) could resolve this discrepancy. A factor of this magnitude appears to be inconsistent with quiet-Sun transition-region measurements (Young 2005) and flaring-coronal observations (Schmeltz et al. 2005; Landi et al. 2007). However, there are concerns whether these abundances measured in the upper solar atmosphere reflect the situation in the photosphere. We have fit solar flare gamma-ray line spectra using newly developed theoretical models of nuclear emission from proton and alpha-particle interactions deep in the chromosphere to determine the Ne/O abundance. We report on our measurements of this ratio in flares observed by the Solar Maximum Mission spectrometer.

  20. A remarkable case of rhabdomyolysis associated with ingestion of energy drink ‘neon volt’

    PubMed Central

    Iyer, Praneet S.; Yelisetti, Rishitha; Miriyala, Varun; Siddiqui, Waqas; Kaji, Anand

    2016-01-01

    Rhabdomyolysis is defined as a syndrome characterized by muscle necrosis and the release of intracellular muscle constituents into the circulation. We present a case of a 35-year-old male who exercised for 2 h after ingesting energy drink and subsequently presented with rhabdomyolysis. After excluding common and uncommon causes of rhabdomyolysis, we reached the conclusion that the likely cause was the ingestion of energy drink ‘NEON VOLT’ in a setting of mild dehydration. Increasing physical activity and intense exercise is becoming a trend in many countries, due to its many health-related benefits such as prevention of obesity. This renewed focus toward optimal fitness has spawned many supplements that aid in improvement of the performance, muscle growth, and recovery. Energy drinks predominantly contain caffeine that is often combined with other supplements to form what manufacturers have termed an ‘energy blend’. Studies have shown that excessive caffeine intake from energy drinks can cause arrhythmias, hypertension, dehydration, sleeplessness, nervousness, and in rare instances, rhabdomyolysis. As per Drug Abuse Warning Network report, there is a sharp increase in the number of emergency department visits involving energy drinks from 1,128 visits in 2005 to 16,053 and 13,114 visits in 2008 and 2009, respectively. Due to emergence of energy drink abuse as a national health problem, Food and Drug Administration has launched a dietary supplement adverse event reporting system for surveillance of any adverse events linked to these agents. PMID:27802855