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Sample records for highly doubly excited

  1. Photoionization study of doubly-excited helium at ultra-high resolution

    SciTech Connect

    Kaindl, G.; Schulz, K.; Domke, M.

    1997-04-01

    Ever since the pioneering work of Madden & Codling and Cooper, Fano & Prats on doubly-excited helium in the early sixties, this system may be considered as prototypical for the study of electron-electron correlations. More detailed insight into these states could be reached only much later, when improved theoretical calculations of the optically-excited {sup 1}P{sup 0} double-excitation states became available and sufficiently high energy resolution ({delta}E=4.0 meV) was achieved. This allowed a systematic investigation of the double-excitation resonances of He up to excitation energies close to the double-ionization threshold, I{sub infinity}=79.003 eV, which stimulated renewed theoretical interest into these correlated electron states. The authors report here on striking progress in energy resolution in this grazing-incidence photon-energy range of grating monochromators and its application to hitherto unobservable states of doubly-excited He. By monitoring an extremely narrow double-excitation resonance of He, with a theoretical lifetime width of less than or equal to 5 {mu}eV, a resolution of {delta}E=1.0 meV (FWHM) at 64.1 eV could be achieved. This ultra-high spectral resolution, combined with high photon flux, allowed the investigation of new Rydberg resonances below the N=3 ionization threshold, I{sub 3}, as well as a detailed comparison with ab-initio calculations.

  2. Doubly Excited States in Be III

    NASA Astrophysics Data System (ADS)

    Andersen, T.; Bentzen, S. M.; Poulsen, O.

    1980-01-01

    The triplet spectrum of doubly excited Be III has been studied in the wavelength region of 75-5000 Å in order to test the validity of the theoretical term values reported by Lipsky et al. The beam-foil excitation technique was applied to effectively populate the doubly excited states. The identified lower-lying, doubly excited states 2p2 3P, 2pnp 3P, or 3D, and 2pnd 3P, or 3D (n = 3, 4) show that the theoretical term values should be slightly modified.

  3. Doubly excited states in some light atoms

    SciTech Connect

    Berry, H.G.; Brooks, R.L.; Hardis, J.E.; Ray, W.J.

    1981-01-01

    We have identified a singlet transition in doubly excited helium: 2p/sup 2/ /sup 1/D - 2p3d /sup 1/D, at 3298 +- 2A with a full width of 54A or 0.061 +- 0.005 eV. This width is in good agreement with a previous measurement and theory for the width of the 2p/sup 2/ /sup 1/D/sub 2/ state. We have remeasured the decay rate of 1s/sup 2/2p/sup 2/P - 1s2p/sup 2/ /sup 2/P in Li I and find it is in good agreement with theory. Several transitions in doubly excited Li II have been identified in the 1000A region. No evidence was found for doubly excited quartet transitions in Li I in the vacuum ultraviolet. We present measurements of wavelengths and fine structure of the 1s2s2p/sup 2/ /sup 5/P - 1s2p/sup 3/ /sup 5/S transitions in C III, N IV and O V.

  4. Double photoionization of doubly-excited lithium

    NASA Astrophysics Data System (ADS)

    Armstrong, G.; Pindzola, M. S.; Kheifets, A.; Schuricke, M.; Veeravalli, G.; Dornes, Ch.; Zhu, G.; Joachimsmeyer, K.; Treusch, R.; Dorn, A.; Colgan, J.

    2012-06-01

    We present triple differential cross sections and recoil ion momentum distributions for double photoionization of the 1s2s2p state of lithium. Double ionization of lithium may be treated as a two-active-electron process, where the ``active'' 2s and 2p electrons move in the field of the ``frozen-core'' Li^2+ 1s state.The time-dependent close-coupling (TDCC) method is used to solve the two-electron time-dependent Schr"odinger equation in full dimensionality. This work is motivated by recent FLASH experiments, which have obtained recoil-ion momentum distributions at a photon energy of 59 eV, where the 1s2s2p state is first reached via a 1s-2p photoexcitation from the initial ground state, and may then be doubly-ionized after the absorption of a second photon. The TDCC calculations in this work treat the subsequent photoionization of this doubly-excited state. The results are compared to those obtained by the convergent close-coupling method and to measurement, and provide a first comparison between theory and experiment in this fundamental few-photon few-body problem.

  5. A simple formula for the energies of doubly excited states

    SciTech Connect

    Lin, C.D.; Watanabe, S.

    1986-11-01

    A simple formula for the energy levels of doubly excited states of atoms and multiply charged ions is derived and expressed in terms of a set of new correlation quantum numbers. The accuracy of the formula is checked by comparing with the results from other elaborate calculations. Modification of the formula for doubly excited states of multielectron atoms are also presented. 12 refs., 2 tabs.

  6. Doubly Excited Resonances in the Positronium Negative Ion

    NASA Technical Reports Server (NTRS)

    Ho, Y.K.

    2007-01-01

    The recent theoretical studies on the doubly excited states of the Ps' ion are described. The results obtained by using the method of complex coordinate rotation show that the three-lepton system behaves very much like an XYX tri-atomic molecule. Furthermore, the recent investigation on the positronium negative ion embedded in Debye plasma environments is discussed. The problem is modeled by the use of a screened Coulomb potential to represent the interaction between the charge particles.

  7. Doubly Excited Resonance States of Helium Atom: Complex Entropies

    NASA Astrophysics Data System (ADS)

    Kuroś, Arkadiusz; Kościk, Przemysław; Saha, Jayanta K.

    2016-09-01

    We provide a diagonal form of a reduced density matrix of S-symmetry resonance states of two electron systems determined under the framework of the complex scaling method. We have employed the variational Hylleraas type wavefunction to estimate the complex entropies in doubly excited resonance states of helium atom. Our results are in good agreement with the corresponding ones determined under the framework of the stabilization method (Lin and Ho in Few-Body Syst 56:157, 2015).

  8. Coherence and correlation in doubly excited heliumlike atoms

    NASA Astrophysics Data System (ADS)

    Burgdörfer, Joachim; Morgenstern, Reinhard

    1988-12-01

    We analyze properties of the density matrix of doubly excited two-electron systems formed in inelastic collisions. Formulas for the two-particle joint angular probability density, the angular correlation function, and the reduced single-particle density are derived. Of particular interest is the interplay between the intrinsic correlations of the stationary two-electron state and collisionally induced coherences. We focus on its effects on the correlated and single-particle motion of the electrons. If one chooses approximate stationary wave functions reflecting the approximate O(4)×O(4)⊃O(4) dynamical symmetry, a simple quasiclassical interpretation of coherence and correlation in terms of shapes and modes of the relative motion of Kepler orbits can be given. The present description is applied to recent experimental results by Van der Straten and Morgenstern [Comments At. Mol. Phys. 19, 243 (1986)].

  9. Partial cross sections of doubly excited helium below the ionization threshold I{sub 7}

    SciTech Connect

    Jiang, Y.H.; Puettner, R.; Poiguine, M.; Kaindl, G.; Hentges, R.; Viefhaus, J.; Becker, U.; Rost, J.M.

    2004-04-01

    Partial photoionization cross sections (PCSs), {sigma}{sub n}, leading to final ionic states of helium, He{sup +}(n), were measured at BESSY II in the region of doubly excited helium up to the ionization threshold I{sub 7} of He{sup +}. The experiments were performed with a time-of-flight (TOF) electron spectrometer and high photon resolution, {delta}E congruent with 6 meV. The results of these measurements are a most critical assessment of the decay dynamics of double-excitation resonances and agree well with those of recent eigenchannel R-matrix calculations. They also confirm the propensity rules set up for the autoionization of doubly excitated states. The mirroring behavior in the PCSs predicted recently by Liu and Starace is only partially observed. By discussing the formulas given by these authors in a more general context, the specific behavior of the PCSs of helium with respect to mirroring can be understood. The mirroring compensation properties between the 'fractional partial cross sections' {gamma}{sub P}={sigma}{sub P}/{sigma}{sub T} and {gamma}{sub Q}={sigma}{sub Q}/{sigma}{sub T}, with {sigma}{sub T}={sigma}{sub P}+{sigma}{sub Q}, are introduced and discussed.

  10. Excitation of {sup 1}S and {sup 3}S Metastable Helium Atoms to Doubly Excited States

    SciTech Connect

    Alagia, M.; Coreno, M.; Farrokhpour, H.; Omidyan, R.; Tabrizchi, M.; Franceschi, P.; Mihelic, A.; Zitnik, M.; Moise, A.; Prince, K. C.; Richter, R.; Soederstroem, J.; Stranges, S.

    2009-04-17

    We present spectra of triplet and singlet metastable helium atoms resonantly photoexcited to doubly excited states. The first members of three dipole-allowed {sup 1,3}P{sup o} series have been observed and their relative photoionization cross sections determined, both in the triplet (from 1s2s {sup 3}S{sup e}) and singlet (from 1s2s {sup 1}S{sup e}) manifolds. The intensity ratios are drastically different with respect to transitions from the ground state. When radiation damping is included the results for the singlets are in agreement with theory, while for triplets spin-orbit interaction must also be taken into account.

  11. (ggr, 2ggr) studies on doubly excited states of molecular hydrogen

    NASA Astrophysics Data System (ADS)

    Odagiri, Takeshi; Murata, Makoto; Kato, Masahiro; Kouchi, Noriyuki

    2004-10-01

    The doubly differential cross sections for the emission of two Lyman-agr photons in photoexcitation of H2 have been measured as a function of incident photon energy in the range of 30-44 eV with a photon-photon coincidence technique. A cross section curve that is free from ionization and thus is attributed entirely to the doubly excited states of H2 has been obtained for the first time. A simple theoretical calculation based on the reflection approximation and semiclassical treatment of the decay dynamics in the Q21Pgru(1) state of H2 has reproduced well the experimental cross section curve. It has been shown that this method, the (ggr, 2ggr) method, is an excellent tool for investigating spectroscopy and dynamics of doubly or multiply excited molecules.

  12. High Performance Variable Speed Drive System and Generating System with Doubly Fed Machines

    NASA Astrophysics Data System (ADS)

    Tang, Yifan

    Doubly fed machines are another alternative for variable speed drive systems. The doubly fed machines, including doubly fed induction machine, self-cascaded induction machine and doubly excited brushless reluctance machine, have several attractive advantages for variable speed drive applications, the most important one being the significant cost reduction with a reduced power converter rating. With a better understanding, improved machine design, flexible power converters and innovated controllers, the doubly fed machines could favorably compete for many applications, which may also include variable speed power generations. The goal of this research is to enhance the attractiveness of the doubly fed machines for both variable speed drive and variable speed generator applications. Recognizing that wind power is one of the favorable clean, renewable energy sources that can contribute to the solution to the energy and environment dilemma, a novel variable-speed constant-frequency wind power generating system is proposed. By variable speed operation, energy capturing capability of the wind turbine is improved. The improvement can be further enhanced by effectively utilizing the doubly excited brushless reluctance machine in slip power recovery configuration. For the doubly fed machines, a stator flux two -axis dynamic model is established, based on which a flexible active and reactive power control strategy can be developed. High performance operation of the drive and generating systems is obtained through advanced control methods, including stator field orientation control, fuzzy logic control and adaptive fuzzy control. System studies are pursued through unified modeling, computer simulation, stability analysis and power flow analysis of the complete drive system or generating system with the machine, the converter and the control. Laboratory implementations and tested results with a digital signal processor system are also presented.

  13. Interplay between collective and single particle excitations around neutron-rich doubly-magic nuclei

    NASA Astrophysics Data System (ADS)

    Leoni, S.

    2016-05-01

    The excitation spectra of nuclei with one or two particles outside a doubly-magic core are expected to be dominated, at low energy, by the couplings between phonon excitations of the core and valence particles. A survey of the experimental situation is given for some nuclei lying in close proximity of neutron-rich doubly-magic systems, such as 47,49Ca, 133Sb and 210Bi. Data are obtained with various types of reactions (multinucleon transfer with heavy ions, cold neutron capture and neutron induced fission of 235U and 241Pu targets), with the employment of complex detection systems based on HPGe arrays. A comparison with theoretical calculations is also presented, in terms of large shell model calculations and of a phenomenological particle-phonon model. In the case of 133Sb, a new microscopic "hybrid" model is introduced: it is based on the coupling between core excitations (both collective and non-collective) of the doubly-magic core and the valence nucleon, using the Skyrme effective interaction in a consistent way.

  14. Doubly excited states of ammonia by scattered electron-ion coincidence measurements

    NASA Astrophysics Data System (ADS)

    Yamamoto, Karin; Sakai, Yasuhiro

    2012-03-01

    To obtain information on the optically forbidden doubly excited states of ammonia (NH3), we performed scattered electron-ion coincidence measurements. First, we observed scattered electrons using electron energy-loss spectroscopy and determined the generalized oscillator strength distribution (GOSD) under 200 eV incident electron energy at a scattering angle of 8°. Ionic GOSDs were also determined by combination with the coincidence signal, which was observed by the time-of-flight mass spectrometer at each energy-loss value, for each ion. The total and partial ionic GOSDs were compared with the experimental results of both photon and fast electron impact. Moreover, the neutral GOSD determined by subtracting the total ionic GOSD from the total was compared with previous results. In addition to the optically forbidden doubly excited states, which were identified by Kato et al (2003 J. Phys. B: At. Mol. Opt. Phys. 36 3541) and Ishikawa et al (2008 J. Phys. B: At. Mol. Opt. Phys. 41 195204), we found a new optically forbidden doubly excited state at around 35 eV.

  15. Purely-long-range krypton molecules in singly and doubly excited binding potentials

    SciTech Connect

    Smith, Z. S.; Harmon, A.; Banister, J.; Norman, R.; Hoogeboom-Pot, K.; Walhout, M.

    2010-01-15

    Diatomic potentials for krypton are computed and also probed experimentally. For a probe-laser wavelength near 811 nm, several strong dipole-dipole interactions produce purely-long-range potential wells in the singly excited manifold of (s+p) potentials and in the doubly excited manifold of (p+p) and (s+d) potentials. Evidence of resonant photoassociation into bound states of these potential wells is observed in the emission of ions and ultraviolet photons from a magneto-optically trapped krypton cloud.

  16. Complex-Scaling Treatment for Doubly Excited Inter-Shell Resonances in H- Interacting with Screened Coulomb (Yukawa) Potentials

    NASA Astrophysics Data System (ADS)

    Ho, Y. K.; Kar, S.

    2012-10-01

    The doubly-excited inter-shell resonance states of the hydrogen negative ion with screened Coulomb potentials are investigated in the framework of complex-scaling method. Highly correlated wave functions with terms up to 1078 in Hylleraas coordinates are used. The resonance parameters for the 2 s3 s 1 S e associated with the H ( N = 2) threshold and the 3 s4 s 1 S e state associated with the H ( N = 3) threshold for various screening strengths are reported. Comparisons are made with other available data in the literature.

  17. Excited-state spectroscopy of singly, doubly and triply-charmed baryons from lattice QCD

    SciTech Connect

    Padmanath, M.; Edwards, Robert G.; Mathur, Nilmani; Peardon, Michael

    2014-07-01

    We present the ground and excited state spectra of singly, doubly and triply-charmed baryons by using dynamical lattice QCD. A large set of baryonic operators that respect the symmetries of the lattice and are obtained after subduction from their continuum analogues are utilized. These operators transform as irreducible representations of SU(3)F symmetry for flavour, SU(4) symmetry for Dirac spins of quarks and O(3) symmetry for orbital angular momenta. Using novel computational techniques correlation functions of these operators are generated and the variational method is exploited to extract excited states. The lattice spectra that we obtain have baryonic states with well-defined total spins up to 7/2 and the low lying states remarkably resemble the expectations of quantum numbers from SU(6)ⓍO(3) symmetry.

  18. Excited state mass spectra of doubly heavy baryons {Ω _{cc}}, {Ω _{bb}}, and {Ω _{bc}}

    NASA Astrophysics Data System (ADS)

    Shah, Zalak; Thakkar, Kaushal; Rai, Ajay Kumar

    2016-10-01

    We discuss the mass spectrum of Ω baryon with two heavy quarks and one light quark ( ccs, bbs, and bcs). The main goal of the paper is to calculate the ground state masses and after that, the positive and negative parity excited states masses are also obtained within a hypercentral constituent quark model, using Coulomb plus linear potential framework. We also added a first order correction to the potential. The mass spectra up to 5S for radial excited states and 1P-5P, 1D-4D, and 1F-2F states for orbital excited states are computed for Ω _{cc}, Ω _{bb}, and Ω _{bc} baryons. Our obtained results are compared with other theoretical predictions, which could be a useful complementary tool for the interpretation of experimentally unknown heavy baryon spectra. The Regge trajectory is constructed in both the (n_r, M2) and the ( J, M2) planes for Ω _{cc}, Ω _{bb}, and Ω _{bc} baryons and their slopes and intercepts are also determined. Magnetic moments of doubly heavy Ω 's are also calculated.

  19. Pump-probe photoelectron velocity-map imaging of autoionizing singly excited 4s14p6np1(n=7,8) and doubly excited 4s24p45s16p1 resonances in atomic krypton

    NASA Astrophysics Data System (ADS)

    Doughty, Benjamin; Haber, Louis H.; Leone, Stephen R.

    2011-10-01

    Pump-probe photoelectron velocity-map imaging, using 27-eV high-harmonic excitation and 786-nm ionization, is used to resolve overlapping autoionizing resonances in atomic krypton, obtaining two-photon photoelectron angular distributions (PADs) for singly and doubly excited states. Two features in the photoelectron spectrum are assigned to singly excited 4s14p6np1 (n = 7,8) configurations and four features provide information about double excitation configurations. The anisotropy parameters for the singly excited 7p configuration are measured to be β2 = 1.61 ± 0.06 and β4 = 1.54 ± 0.16 while the 8p configuration gives β2 = 1.23 ± 0.19 and β4 = 0.60 ± 0.15. These anisotropies most likely represent the sum of overlapping PADs from states of singlet and triplet spin multiplicities. Of the four bands corresponding to ionization of doubly excited states, two are assigned to 4s24p45s16p1 configurations that are probed to different J-split ion states. The two remaining doubly excited states are attributed to a previously observed, but unassigned, resonance in the vacuum-ultraviolet photoabsorption spectrum. The PADs from each of the double excitation states are also influenced by overlap from neighboring states that are not completely spectrally resolved. The anisotropies of the observed double excitation states are reported, anticipating future theoretical and experimental work to separate the overlapping PADs into the state resolved PADs. The results can be used to test theories of excited state ionization.

  20. Obtaining Hartree-Fock and density functional theory doubly excited states with Car-Parrinello density matrix search

    NASA Astrophysics Data System (ADS)

    Liang, Wenkel; Isborn, Christine M.; Li, Xiaosong

    2009-11-01

    The calculation of doubly excited states is one of the major problems plaguing the modern day excited state workhorse methodology of linear response time dependent Hartree-Fock (TDHF) and density function theory (TDDFT). We have previously shown that the use of a resonantly tuned field within real-time TDHF and TDDFT is able to simultaneously excite both the α and β electrons to achieve the two-electron excited states of minimal basis H2 and HeH+ [C. M. Isborn and X. Li, J. Chem. Phys. 129, 204107 (2008)]. We now extend this method to many electron systems with the use of our Car-Parrinello density matrix search (CP-DMS) with a first-principles fictitious mass method for wave function optimization [X. Li, C. L. Moss, W. Liang, and Y. Feng, J. Chem. Phys. 130, 234115 (2009)]. Real-time TDHF/TDDFT is used during the application of the laser field perturbation, driving the electron density toward the doubly excited state. The CP-DMS method then converges the density to the nearest stationary state. We present these stationary state doubly excited state energies and properties at the HF and DFT levels for H2, HeH+, lithium hydride, ethylene, and butadiene.

  1. Formation of metastable atomic hydrogen in the 2s state from symmetry-resolved doubly excited states of molecular hydrogen

    SciTech Connect

    Odagiri, Takeshi; Kumagai, Yoshiaki; Nakano, Motoyoshi; Tanabe, Takehiko; Kitajima, Masashi; Kouchi, Noriyuki; Suzuki, Isao H.

    2011-11-15

    The cross sections for the formation of the metastable atomic hydrogen in the 2s state in photoexcitation of H{sub 2} and D{sub 2} were measured as a function of the incident photon energy in the range of the doubly excited states with their symmetries of the electronic states, {sup 1}{Sigma}{sub u}{sup +} or {sup 1}{Pi}{sub u}, being resolved. It has turned out from the comparison with the cross-section curves for other dissociation processes and the theoretical calculation [J. D. Bozek et al., J. Phys. B 39, 4871 (2006)] that the Q{sub 2}{sup 1}{Pi}{sub u}(1) doubly excited state of H{sub 2} dissociates into both H(2s) + H(2p) and H(2p) + H(2p). The dissociation dynamics of this state has been discussed in terms of the nonadiabatic transition during neutral dissociations.

  2. Attosecond XUV absorption spectroscopy of doubly excited states in helium atoms dressed by a time-delayed femtosecond infrared laser

    NASA Astrophysics Data System (ADS)

    Yang, Z. Q.; Ye, D. F.; Ding, Thomas; Pfeifer, Thomas; Fu, L. B.

    2015-01-01

    In the present paper, we investigate the time-resolved transient absorption spectroscopy of doubly excited states of helium atoms by solving the time-dependent two-electron Schrödinger equation numerically based on a one-dimensional model. The helium atoms are subjected to an extreme ultraviolet (XUV) attosecond pulse and a time-delayed infrared (IR) few-cycle laser pulse. A superposition of doubly excited states populated by the XUV pulse is identified, which interferes with the direct ionization pathway leading to Fano resonance profiles in the photoabsorption spectrum. In the presence of an IR laser, however, the Fano line profiles are strongly modified: A shifting, splitting, and broadening of the original absorption lines is observed when the XUV attosecond pulse and infrared few-cycle laser pulse overlap in time, which is in good agreement with recent experimental results. At certain time delays, we observe symmetric Lorentz, inverted Fano profiles, and even negative absorption cross sections indicating that the XUV light can be amplified during the interaction with atoms. We further prove that the above pictures are general for different doubly excited states by suitably varying the frequency of the IR field to coherently couple the corresponding states.

  3. High spin states and isomeric decays in doubly-odd 208Fr

    NASA Astrophysics Data System (ADS)

    Kanjilal, D.; Bhattacharya, S.; Goswami, A.; Kshetri, R.; Raut, R.; Saha, S.; Bhowmik, R. K.; Gehlot, J.; Muralithar, S.; Singh, R. P.; Jnaneswari, G.; Mukherjee, G.; Mukherjee, B.

    2010-10-01

    Neutron deficient isotopes of francium ( Z=87, N˜121-123) as excited nuclei were produced in the fusion-evaporation reaction: 197Au( 16O, xn) 213 - xFr at 100 MeV. The γ rays from the residues were observed through the high sensitivity Germanium Clover detector array INGA. The decay of the high spin states and the isomeric states of the doubly-odd 208Fr nuclei, identified from the known sequence of ground state transitions, were observed. The half-lives of the E=194(2) keV isomeric transition, known from earlier observations, was measured to be T=233(18) ns. A second isomeric transition at E=383(2) keV and T=33(7) ns was also found. The measured half-lives were compared with the corresponding single particle estimates, based on the level scheme obtained from the experiment.

  4. Measurement of the autoionization lifetime of the energetically lowest doubly excited Q_1\\,^1\\Sigma ^+_{u} state in H2 using electron ejection asymmetry

    NASA Astrophysics Data System (ADS)

    Fischer, Andreas; Sperl, Alexander; Cörlin, Philipp; Schönwald, Michael; Meuren, Sebastian; Ullrich, Joachim; Pfeifer, Thomas; Moshammer, Robert; Senftleben, Arne

    2014-01-01

    The autoionization lifetime of doubly excited H2 created by single photon absorption has been measured by means of a kinematically complete study. For dissociative ionization the experimentally observed asymmetry in the electron ejection direction with respect to the emitted proton is used to disentangle the two interfering pathways, direct ionization and autoionization. This allows us to determine the autoionization lifetime of the energetically lowest doubly excited Q_1\\,^1\\Sigma _{u}^+(1) state for a large range of internuclear distances, including the previously inaccessible small values. Excellent agreement with available ab initio calculations is obtained.

  5. Energies, radiative rates, and Auger widths of the doubly-excited 1s23l3l‧ states of the Be isoelectronic sequence

    NASA Astrophysics Data System (ADS)

    Li, Kaikai; Zhuo, Lin; Gou, Bingcong

    2016-10-01

    Relativistic energies, radiative and Auger rates of the high-lying doubly-excited 1s23l3l‧1,3L states of the Be isoelectronic sequence are studied using the saddle-point variational method with complex rotation. The relativistic and mass polarization corrections are calculated using the first-order perturbation theory. Autoionizing levels and widths above the 1s22s and 1s22p thresholds are considered and their contributions are analysed. The regular change of the radiative and Auger rates along the Be isoelectronic sequence is discussed in this work. The results are compared with the available experimental and other theoretical data in the literature.

  6. Ground and excited states of doubly open-shell nuclei from ab initio valence-space Hamiltonians

    NASA Astrophysics Data System (ADS)

    Stroberg, S. R.; Hergert, H.; Holt, J. D.; Bogner, S. K.; Schwenk, A.

    2016-05-01

    We present ab initio predictions for ground and excited states of doubly open-shell fluorine and neon isotopes based on chiral two- and three-nucleon interactions. We use the in-medium similarity renormalization group to derive mass-dependent s d valence-space Hamiltonians. The experimental ground-state energies are reproduced through neutron number N =14 , beyond which a new targeted normal-ordering procedure improves agreement with data and large-space multireference calculations. For spectroscopy, we focus on neutron-rich F-2623 and Ne-2624 isotopes near N =14 ,16 magic numbers. In all cases we find agreement with experiment and established phenomenology. Moreover, yrast states are well described in 20Ne and 24Mg, providing a path toward an ab initio description of deformation in the medium-mass region.

  7. Doubly excited {sup 3}P{sup e} resonance states of two-electron positive ions in Debye plasmas

    SciTech Connect

    Hu, Xiao-Qing; Wang, Yang; Kar, Sabyasachi E-mail: karsabyasachi@yahoo.com; Jiang, Zishi; Jiang, Pinghui

    2015-11-15

    We investigate the doubly excited {sup 3}P{sup e} resonance states of two-electron positive ions Li{sup +}, Be{sup 2+}, B{sup 3+}, and C{sup 4+} by employing correlated exponential wave functions. In the framework of the stabilization method, we calculate two series (3pnp and 3dnd) of {sup 3}P{sup e} resonances below the N = 3 threshold. The {sup 3}P{sup e} resonance parameters (resonance energies and widths) are reported for the first time as a function of the screening parameter. For free-atomic cases, comparisons are made with the reported results and few resonance states are reported for the first time.

  8. Comparison of doubly labeled water with respirometry at low- and high-activity levels

    SciTech Connect

    Westerterp, K.R.; Brouns, F.; Saris, W.H.; ten Hoor, F.

    1988-07-01

    In previous studies the doubly labeled water method for measuring energy expenditure in free-living humans has been validated against respirometry under sedentary conditions. In the present investigation, energy expenditure is measured simultaneously with doubly labeled water and respirometry at low- and high-activity levels. Over 6 days, five subjects were measured doing mainly sedentary activities like desk work; their average daily metabolic rate was 1.40 +/- 0.09 (SD) times sleeping metabolic rate. Four subjects were measured twice over 3.5 days, including 2 days with heavy bicycle ergometer work, resulting in an average daily metabolic rate of 2.61 +/- 0.25 (SD) times sleeping metabolic rate. At the low-activity level, energy expenditures from the doubly labeled water method were on the average 1.4 +/- 3.9% (SD) larger than those from respirometry. At the high-activity level, the doubly labeled water method yielded values that were 1.0 +/- 7.0% (SD) lower than those from respirometry. Results demonstrate the utility of the doubly labeled water method for the determination of energy expenditure in the range of activity levels in daily life.

  9. Excitation of helium Rydberg states and doubly excited resonances in strong extreme ultraviolet fields: Full-dimensional quantum dynamics using exponentially tempered Gaussian basis sets

    SciTech Connect

    Kaprálová-Žďánská, Petra Ruth; Šmydke, Jan; Civiš, Svatopluk

    2013-09-14

    Recently optimized exponentially tempered Gaussian basis sets [P. R. Kapralova-Zdanska and J. Smydke, J. Chem. Phys. 138, 024105 (2013)] are employed in quantitative simulations of helium absorption cross-sections and two-photon excitation yields of doubly excited resonances. Linearly polarized half-infinite and Gaussian laser pulses at wavelengths 38–58 nm and large intensities up to 100 TW/cm{sup 2} are considered. The emphasis is laid on convergence of the results with respect to the quality of the Gaussian basis sets (typically limited by a number of partial waves, density, and spatial extent of the basis functions) as well as to the quality of the basis set of field-free states (typically limited by the maximum rotational quantum number and maximum excitation of the lower electron). Particular attention is paid to stability of the results with respect to varying complex scaling parameter. Moreover, the study of the dynamics is preceded by a thorough check of helium energies and oscillator strengths as they are obtained with the exponentially tempered Gaussian basis sets, being also compared with yet unpublished emission wavelengths measured in electric discharge experiments.

  10. Absolute cross sections and branching ratios for the radiative decay of doubly excited helium determined by photon-induced fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Mickat, S.; Schartner, K.-H.; Kammer, Sv; Schill, R.; Werner, L.; Klumpp, S.; Ehresmann, A.; Schmoranzer, H.; Sukhorukov, V. L.

    2005-08-01

    The decay of doubly excited helium states below the N = 2 threshold, cascading radiatively over three steps, were investigated using the photon-induced fluorescence spectroscopy (PIFS) at BESSY II. Absolute cross sections as the product of the resonance excitation cross section of the doubly excited states and their fluorescence rate to decay into the singly excited 1sms(1S) and 1smd(1D) states were measured. The experiments showed that the (sp,2n+)(1P) states decay predominantly into the 1sns(1S) states, whereas the (pd,2n)(1P) states prefer to decay into the 1snd(1D) states. For the (sp,2n-)(1P) states with n = 4, 5 and 6 we observed a broad and complex decay pattern. In addition the angular distribution of the fluorescence radiation was measured. The results are in good agreement with theoretical predictions. Furthermore, the weakening of the LS coupling scheme and the mixing between singlet and triplet states in helium was confirmed by observation of the 1s6d(3D0,1,2) → 1s2p(3P0,1,2) transition on a doubly excited singlet state.

  11. Pump-probe photoelectron velocity-map imaging of autoionizing singly excited 4s{sup 1}4p{sup 6}np{sup 1}(n=7,8) and doubly excited 4s{sup 2}4p{sup 4}5s{sup 1}6p{sup 1} resonances in atomic krypton

    SciTech Connect

    Doughty, Benjamin; Haber, Louis H.; Leone, Stephen R.

    2011-10-15

    Pump-probe photoelectron velocity-map imaging, using 27-eV high-harmonic excitation and 786-nm ionization, is used to resolve overlapping autoionizing resonances in atomic krypton, obtaining two-photon photoelectron angular distributions (PADs) for singly and doubly excited states. Two features in the photoelectron spectrum are assigned to singly excited 4s{sup 1}4p{sup 6}np{sup 1} (n = 7,8) configurations and four features provide information about double excitation configurations. The anisotropy parameters for the singly excited 7p configuration are measured to be {beta}{sub 2} = 1.61 {+-} 0.06 and {beta}{sub 4} = 1.54 {+-} 0.16 while the 8p configuration gives {beta}{sub 2} = 1.23 {+-} 0.19 and {beta}{sub 4} = 0.60 {+-} 0.15. These anisotropies most likely represent the sum of overlapping PADs from states of singlet and triplet spin multiplicities. Of the four bands corresponding to ionization of doubly excited states, two are assigned to 4s{sup 2}4p{sup 4}5s{sup 1}6p{sup 1} configurations that are probed to different J-split ion states. The two remaining doubly excited states are attributed to a previously observed, but unassigned, resonance in the vacuum-ultraviolet photoabsorption spectrum. The PADs from each of the double excitation states are also influenced by overlap from neighboring states that are not completely spectrally resolved. The anisotropies of the observed double excitation states are reported, anticipating future theoretical and experimental work to separate the overlapping PADs into the state resolved PADs. The results can be used to test theories of excited state ionization.

  12. Supplemental activation method for high-efficiency electron-transfer dissociation of doubly protonated peptide precursors.

    PubMed

    Swaney, Danielle L; McAlister, Graeme C; Wirtala, Matthew; Schwartz, Jae C; Syka, John E P; Coon, Joshua J

    2007-01-15

    Electron-transfer dissociation (ETD) delivers the unique attributes of electron capture dissociation to mass spectrometers that utilize radio frequency trapping-type devices (e.g., quadrupole ion traps). The method has generated significant interest because of its compatibility with chromatography and its ability to: (1) preserve traditionally labile post-translational modifications (PTMs) and (2) randomly cleave the backbone bonds of highly charged peptide and protein precursor ions. ETD, however, has shown limited applicability to doubly protonated peptide precursors, [M + 2H]2+, the charge and type of peptide most frequently encountered in "bottom-up" proteomics. Here we describe a supplemental collisional activation (CAD) method that targets the nondissociated (intact) electron-transfer (ET) product species ([M + 2H]+*) to improve ETD efficiency for doubly protonated peptides (ETcaD). A systematic study of supplementary activation conditions revealed that low-energy CAD of the ET product population leads to the near-exclusive generation of c- and z-type fragment ions with relatively high efficiency (77 +/- 8%). Compared to those formed directly via ETD, the fragment ions were found to comprise increased relative amounts of the odd-electron c-type ions (c+*) and the even-electron z-type ions (z+). A large-scale analysis of 755 doubly charged tryptic peptides was conducted to compare the method (ETcaD) to ion trap CAD and ETD. ETcaD produced a median sequence coverage of 89%-a significant improvement over ETD (63%) and ion trap CAD (77%).

  13. High-spin states in doubly odd sup 122 Cs

    SciTech Connect

    Xu, N.; Liang, Y.; Ma, R.; Paul, E.S.; Fossan, D.B. ); Latvakoski, H.M. )

    1990-06-01

    High-spin states in {sup 122}Cs have been studied via the {sup 112}Sn({sup 12}C,{ital pn}) reaction. Two {Delta}{ital I}=1 band structures, along with {ital E}2 crossover transitions, are observed. One band is believed to be based on the {pi}{ital h}{sub 11/2}{direct product}{nu}{ital g}{sub 7/2} configuration. A band crossing is observed at a rotational frequency of {h bar}{omega}{sub {ital c}}=0.46 MeV which is expected from the alignment of an {ital h}{sub 11/2} neutron pair. The second band, believed to be based on the {pi}{ital g}{sub 7/2}{direct product}{nu}{ital h}{sub 11/2} configuration, is observed up to high spin. The two signatures of this negative parity band show a small signature splitting as well as a common upbend. Calculations with both the cranked shell model (CSM) and a geometrical model are utilized to define the configurations and quasiparticles corresponding to the band crossings in this nucleus.

  14. Neutron transport in doubly heterogeneous media of high temperature reactors

    NASA Astrophysics Data System (ADS)

    Gert, Godfree

    The AGENT code methodology was extended to include the ability to simulate the neutronics of the Very High Temperature Reactor (VHTR). This involved changes to both the geometry and flux solver modules. Changes to the geometry module included the extension of the AGENT lattice mode to model hexagonal assemblies. This involved the modification of existing primitive bodies and the addition of new ones to the AGENT library of primitive bodies. Changes to the flux solver enables AGENT to treat the Double Heterogeneity problem that results from the random distribution of the fuel grains in the graphite matrix of the VHTR fuel region. The implemented Double Heterogeneity treatment uses renewal theory with a Poisson and an isotropic distributions assumed for the chord lengths in the graphite matrix and the fuel grain regions respectively. Assuming collisionless transport, the resulting set of closed renewal equations are used to derive the analytical expressions for the flux along the neutron paths in the matrix and fuel grain regions. First flight collision and escape probabilities are used to solve for the flux in the fuel grain regions and combined with the Method of Characteristics the neutron flux in the entire double heterogeneous region is solved. The resulting modifications to the AGENT code have been verified against relevant benchmarks.

  15. Highly conducting and crystalline doubly doped tin oxide films fabricated using a low-cost and simplified spray technique

    NASA Astrophysics Data System (ADS)

    Ravichandran, K.; Muruganantham, G.; Sakthivel, B.

    2009-11-01

    Doubly doped (simultaneous doping of antimony and fluorine) tin oxide films (SnO 2:Sb:F) have been fabricated by employing an inexpensive and simplified spray technique using perfume atomizer from aqueous solution of SnCl 2 precursor. The structural studies revealed that the films are highly crystalline in nature with preferential orientation along the (2 0 0) plane. It is found that the size of the crystallites of the doubly doped tin oxide films is larger (69 nm) than that (27 nm) of their undoped counterparts. The dislocation density of the doubly doped film is lesser (2.08×10 14 lines/m 2) when compared with that of the undoped film (13.2×10 14 lines/m 2), indicating the higher degree of crystallinity of the doubly doped films. The SEM images depict that the films are homogeneous and uniform. The optical transmittance in the visible range and the optical band gap of the doubly doped films are 71% and 3.56 eV respectively. The sheet resistance (4.13 Ω/□) attained for the doubly doped film in this study is lower than the values reported for spray deposited fluorine or antimony doped tin oxide films prepared from aqueous solution of SnCl 2 precursor (without using methanol or ethanol).

  16. Ultrafast spectroscopy of super high frequency mechanical modes of doubly clamped beams

    NASA Astrophysics Data System (ADS)

    Ristow, Oliver; Merklein, Moritz; Grossmann, Martin; Hettich, Mike; Schubert, Martin; Bruchhausen, Axel; Grebing, Jochen; Erbe, Artur; Mounier, Denis; Gusev, Vitalyi; Scheer, Elke; Dekorsy, Thomas; Barretto, Elaine C. S.

    2013-12-01

    We use ultrafast pump-probe spectroscopy to study the mechanical vibrations in the time domain of doubly clamped silicon nitride beams. Beams with two different clamping conditions are investigated. Finite element method calculations are performed to analyse the mode spectra of both structures. By calculating the strain integral on the surface of the resonators, we are able to reproduce the effect of the detection mechanism and identify all the measured modes. We show that our spectroscopy technique combined with our modelling tools allow the investigation of several different modes in the super high frequency range (3-30 GHz) and above, bringing more information about the vibration modes of nanomechanical resonators.

  17. First excited states in doubly-odd {sup 110}Sb: Smooth band termination in the A {approx} 110 region

    SciTech Connect

    Lane, G.J.; Fossan, D.B.; Thorslund, I.

    1996-11-01

    Excited states have been identified for the first time in {sup 110}Sb in a comprehensive series of {gamma}-spectroscopy experiments, including recoil-mass and neutron-field measurements. Three high-spin decoupled bands with configurations based on 2p-2h excitations across the Z = 50 shell gap, are observed to show the features of smooth band termination, the first such observation in an odd-odd nucleus. The yrast intruder band has been connected to the low spin levels and is tentatively identified up to its predicred termination at I{sup {pi}} = (45{sup +}). Detailed configuration assignments are made through comparison with configuration-dependent cranked Nilsson-Strutinsky calculations; excellent agreement with experiment is obtained. The systematic occurrence of smoothly terminating bands in the neighboring isotopes is discussed.

  18. High Frequency Chandler Wobble Excitation

    NASA Astrophysics Data System (ADS)

    Seitz, F.; Stuck, J.; Thomas, M.

    2003-04-01

    and OMCT forcing fields give no hint for increased excitation power in the Chandler band. Thus it is assumed, that continuous high frequency excitation due to stochastic weather phenomena is responsible for the perpetuation of the Chandler wobble.

  19. Ultrafast spectroscopy of super high frequency mechanical modes of doubly clamped beams

    SciTech Connect

    Ristow, Oliver; Merklein, Moritz; Grossmann, Martin; Hettich, Mike; Schubert, Martin; Bruchhausen, Axel; Scheer, Elke; Dekorsy, Thomas; Barretto, Elaine C. S.; Grebing, Jochen; Erbe, Artur; Mounier, Denis; Gusev, Vitalyi

    2013-12-02

    We use ultrafast pump-probe spectroscopy to study the mechanical vibrations in the time domain of doubly clamped silicon nitride beams. Beams with two different clamping conditions are investigated. Finite element method calculations are performed to analyse the mode spectra of both structures. By calculating the strain integral on the surface of the resonators, we are able to reproduce the effect of the detection mechanism and identify all the measured modes. We show that our spectroscopy technique combined with our modelling tools allow the investigation of several different modes in the super high frequency range (3-30 GHz) and above, bringing more information about the vibration modes of nanomechanical resonators.

  20. Helium doubly excited states with zero angular momentum and electrons located on the same side of the nucleus

    SciTech Connect

    de Prunele, E. )

    1992-09-01

    A particular set of two-electron atomic resonances for the helium atom with zero total orbital angular momentum ({ital S} states) has been recently studied theoretically (K. Richter and D. Wintgen, J. Phys. B 24, L565 (1991)). These resonances essentially have both electrons on the same side of the nucleus and the outer electron frozen.'' The present work suggests that the energies of these resonances correspond, when the degree of excitation of both electrons increases, to the energies of resonances associated with the Hamiltonian {ital H}={ital p}{sup 2}/2+{ital p}{prime}{sup 2}/2{minus}{ital Z}/{ital r}{minus}{ital Z}/{ital r}{prime}+1/{vert bar}{vert bar}{ital r}{vert bar}{minus}{vert bar}{ital r}{prime}{vert bar}{vert bar} in a space where both particles have zero angular momentum ({ital scrl}={ital scrl}{prime}=0). Moreover, the energy of each of these resonances appears to be that of the lowest member of an almost unperturbed Rydberg series of resonances converging to a single ionization threshold of He. The analysis of the problem relies on the method of o(4,2) operator replacements generalized by the method of complex scaling.

  1. Core-excited states in the doubly magic {sup 68}Ni and its neighbor {sup 69}Cu

    SciTech Connect

    Ishii, T.; Asai, M.; Matsuda, M.; Ichikawa, S.; Makishima, A.; Hossain, I.; Ogawa, M.; Hasegawa, J.

    1999-11-16

    The ({nu}g{sub 9/2}{sup 2}{nu}p{sub 1/2}{sup -2}){sub 8{sup +}} isomer with T{sub 1/2}=23(1) ns at 4208 keV in {sup 68}Ni was found by deep-inelastic collisions of {sup 70}Zn(8 MeV/nucleon)+{sup 198}Pt and the {nu}g{sub 9/2} E2 effective charge was determined to be 1.5(1)e. In {sup 69}Cu, the ({pi}p{sub 3/2}{nu}g{sub 9/2}{sup 2}{nu}p{sub 1/2}{sup -2}){sub 19/2{sup -}} isomer with T{sub 1/2}=22(1) ns at 3691 keV was identified and its decay data were calculated quite accurately by a parameter-free shell model calculation using experimental level energies. Proton 2p-1h excitation, fed by another T{sub 1/2}=39(6) ns isomer, induces large collectivity in {sup 69}Cu.

  2. Core-Excited States in the Doubly Magic {sup 68}Ni and its Neighbor {sup 69}Cu

    SciTech Connect

    T. Ishii; M. Asai; A. Makishima; I. Hossain; M. Ogawa; J. Hasegawa; M. Matsuda; S. Ichikawa

    1999-12-31

    The ({nu}g{sub 9/2}{sup 2}{nu}p{sub 1/2}{sup -2}){sub 8+} isomer with T{sub 1/2} = 23(1) ns at 4208 keV in {sup 68}Ni was found by deep-inelastic collisions of {sup 70}Zn(8MeV/nucleon)+ {sup 198}Pt and the {nu}g{sub 9/2} E2 effective charge was determined to be 1.5(1)e. In {sup 69}Cu, the ({pi}p{sub 3/2}{nu}g{sub 9/2}{sup 2}{nu}p{sub 1/2}{sup -2}){sub 19/2-} isomer with T{sub 1/2}22(1) ns at 3691 keV was identified and its decay data were calculated quite accurately by a parameter-free shell model calculation using experimental level energies. Proton 2p-1h excitation, fed by another T{sub 1/2} = 39(6) ns isomer, induces large collectivity in {sup 69}Cu.

  3. Static quadrupole moment of high-spin isomers in the doubly-odd {sup 214}Fr nucleus

    SciTech Connect

    Neyens, G.; Van Asbroeck, I.; Coussement, R.

    1995-06-01

    We have determined the spectroscopic quadrupole moment of two high-spin isomers ({ital I}=11 {h_bar} and {ital I}=32 {h_bar}) which have recently been identified in the doubly-odd {sup 214}Fr nucleus. The data have been extracted from a series of former level mixing spectroscopy (LEMS) measurements which had been performed to measure quadrupole moments of high-spin isomers in {sup 211,212,213}Fr isotopes. The quadrupole frequencies were measured in natural and enriched poly- and single-crystalline T1 at different temperatures.

  4. Nickel and titanium doubly doped lanthanum strontium chromite for high temperature electrochemical devices

    NASA Astrophysics Data System (ADS)

    Gupta, Sapna; Singh, Prabhakar

    2016-02-01

    Lanthanum chromite based materials are promising candidate for use as electrochemical components in high temperature electrochemical devices. In this study, nickel and titanium doubly doped lanthanum strontium chromites are developed and the effects of nickel and titanium co-doping of the chromite perovskite La0.85Sr0.15Cr1-2yNiyTiyO3-δ (0.05 ≤ y ≤ 0.3) on the electrical conductivity, chemical stability, microstructure, density, thermal expansion and electrochemical performance are measured. Density and the electrical conductivity increases with nickel concentration whereas Sr-segregation on the surface of La0.85Sr0.15Cr1-2yNiyTiyO3-δ has been observed for y ≥ 0.2 and is associated with reduction in the electrical conductivity. For y = 0.1, La0.85Sr0.15Cr1-2yNiyTiyO3-δ shows the highest electrical conductivity in air and reducing atmosphere (PO2 ∼10-24 atm). The conductivity of La0.85Sr0.15Cr1-2yNiyTiyO3-δ (y = 0.1) in reducing atmosphere (3.58 S cm-1 at 950 °C) also remains higher than the most widely investigated compositions such as (La0.75Sr0.25)0.95Cr0.5Mn0.5O3-δ (2.81 S cm-1) and (La0.75Sr0.25)0.95Cr0.7Fe0.3O3-δ (1.41 S cm-1). Smaller deviation in the oxygen stoichiometry is similarly observed for La0.85Sr0.15Cr0.8Ni0.1Ti0.1O3-δ (δ = 0.011) when compared to La0.75Sr0.25CrO3-δ (δ = 0.091), La0.75Sr0.25Cr0.5Mn0.5O3-δ (δ = 0.175) and La0.75Sr0.25Cr0.5Fe0.5O3-δ (δ = 0.148) at 1000 °C and ∼10-24 atm. Highest electrochemical performance and structural/interfacial stability is obtained for new composition La0.85Sr0.15Cr0.8Ni0.1Ti0.1O3-δ (LSCNT0.1) when mixed with 8YSZ in both oxidizing and reducing atmosphere.

  5. New Measurements of Doubly Ionized Iron Group Spectra by High Resolution Fourier Transform and Grating Spectroscopy

    NASA Technical Reports Server (NTRS)

    Smillie, D. G.; Pickering, J. C.; Blackwell-Whitehead, R. J.; Smith, Peter L.; Nave, G.

    2006-01-01

    We report new measurements of doubly ionized iron group element spectra, important in the analysis of B-type (hot) stars whose spectra they dominate. These measurements include Co III and Cr III taken with the Imperial College VUV Fourier transform (FT) spectrometer and measurements of Co III taken with the normal incidence vacuum spectrograph at NIST, below 135 nm. We report new Fe III grating spectra measurements to complement our FT spectra. Work towards transition wavelengths, energy levels and branching ratios (which, combined with lifetimes, produce oscillator strengths) for these ions is underway.

  6. New Atomic Data for Doubly Ionized Iron Group Atoms by High Resolution UV Fourier Transform Spectroscopy

    NASA Technical Reports Server (NTRS)

    Smith, Peter L.; Pickering, Juliet C.; Thorne, A. P.

    2002-01-01

    Currently available laboratory spectroscopic data of doubly ionized iron-group element were obtained about 50 years ago using spectrographs of modest dispersion, photographic plates, and eye estimates of intensities. The accuracy of the older wavelength data is about 10 mAngstroms at best, whereas wavelengths are now needed to an accuracy of 1 part in 10(exp 6) to 10(exp 7) (0.2 to 2 mAngstroms at 2000 Angstroms). The Fourier transform (FT) spectroscopy group at Imperial College, London, and collaborators at the Harvard College Observatory have used a unique VUV FT spectrometer in a program focussed on improving knowledge of spectra of many neutral and singly and doubly ionized, astrophysically important, iron group elements. Spectra of Fe II and Fe III have been recorded at UV and VUV wavelengths with signal-to-noise ratios of several hundred for the stronger lines. Wavelengths and energy levels for Fe III are an order of magnitude more accurate than previous work; analysis is close to completion. f-values for Fe II have been published.

  7. Recent development of doubly curved crystal focusing optics and their applications for micro XRF

    NASA Astrophysics Data System (ADS)

    Chen, Zewu

    1999-11-01

    Three-dimensional focusing of x-rays can be achieved by doubly-curved crystals through diffraction from a small laboratory x-ray source. Recently it has been demonstrated that an intense monochromatic x-ray microprobe can be obtained with the use of a doubly-curved mica crystal. Due to monochromatic excitation using doubly-curved crystal optics, exceptionally low background has been demonstrated in the application to micro x-ray fluorescence (MXRF). Low background and high intensity gain significantly improve the detection limit for MXRF. In this paper, the focusing and diffraction properties of a doubly-curved Johann point-focusing crystal optic for Cu K(alpha) x-rays from a microfocus x-ray source is presented. Experimental data on spot size, beam intensity, effect of source position for the optics, and MXRF spectra are discussed.

  8. High-spin states in doubly odd {sup 162,164}Lu

    SciTech Connect

    Cardona, M.A.; Hojman, D.; Debray, M.E.; Kreiner, A.J.; Somacal, H.; Cardona, M.A.; Hojman, D.; Debray, M.E.; Kreiner, A.J.; Somacal, H.; Davidson, J.; Davidson, M.; Davidson, J.; Hojman, D.; Kreiner, A.J.; Davidson, M.; Napoli, D.R.; Burch, R.; De Acuna, D.; Rico, J.; Bazzacco, D.; Lenzi, S.M.; Rossi Alvarez, C.; Blasi, N.; Lo Bianco, G.

    1997-08-01

    High-spin states in {sup 162}Lu and {sup 164}Lu have been studied by means of in-beam {gamma}-ray spectroscopy techniques using the multidetector array GASP. The excited states have been populated through the {sup 139}La({sup 28}Si,5n){sup 162}Lu and {sup 139}La[{sup 29(30)}Si,4(5)n]{sup 164}Lu reactions. Level schemes were constructed for both nuclei. Configurations for the rotational bands have been discussed. Alignments, band crossing frequencies, and B(M1)/B(E2) ratios have been analyzed in the framework of the cranking model. The systematic evolution of the signature inversion in the {pi}h{sub 11/2}{circle_times}{nu}i{sub 13/2} structure is reviewed. {copyright} {ital 1997} {ital The American Physical Society}

  9. Dynamical analysis of highly excited molecular spectra

    SciTech Connect

    Kellman, M.E.

    1993-12-01

    The goal of this program is new methods for analysis of spectra and dynamics of highly excited vibrational states of molecules. In these systems, strong mode coupling and anharmonicity give rise to complicated classical dynamics, and make the simple normal modes analysis unsatisfactory. New methods of spectral analysis, pattern recognition, and assignment are sought using techniques of nonlinear dynamics including bifurcation theory, phase space classification, and quantization of phase space structures. The emphasis is chaotic systems and systems with many degrees of freedom.

  10. The decay of highly excited open strings

    NASA Technical Reports Server (NTRS)

    Mitchell, D.; Turok, N.; Wilkinson, R.; Jetzer, P.

    1988-01-01

    The decay rates of leading edge Regge trajectory states are calculated for very high level number in open bosonic string theories, ignoring tachyon final states. The optical theorem simplifies the analysis while enabling identification of the different mass level decay channels. The main result is that (in four dimensions) the greatest single channel is the emission of a single photon and a state of the next mass level down. A simple asymptotic formula for arbitrarily high level number is given for this process. Also calculated is the total decay rate exactly up to N=100. It shows little variation over this range but appears to decrease for larger N. The formalism is checked in examples and the decay rate of the first excited level calculated for open superstring theories. The calculation may also have implications for high spin meson resonances.

  11. Hexagonal ice transforms at high pressures and compression rates directly into "doubly metastable" ice phases.

    PubMed

    Bauer, Marion; Winkel, Katrin; Toebbens, Daniel M; Mayer, Erwin; Loerting, Thomas

    2009-12-14

    We report compression and decompression experiments of hexagonal ice in a piston cylinder setup in the temperature range of 170-220 K up to pressures of 1.6 GPa. The main focus is on establishing the effect that an increase in compression rate up to 4000 MPa/min has on the phase changes incurred at high pressures. While at low compression rates, a phase change to stable ice II takes place (in agreement with earlier comprehensive studies), we find that at higher compression rates, increasing fractions and even pure ice III forms from hexagonal ice. We show that the critical compression rate, above which mainly the metastable ice III polymorph is produced, decreases by a factor of 30 when decreasing the temperature from 220 to 170 K. At the highest rate capable with our equipment, we even find formation of an ice V fraction in the mixture, which is metastable with respect to ice II and also metastable with respect to ice III. This indicates that at increasing compression rates, progressively more metastable phases of ice grow from hexagonal ice. Since ices II, III, and V differ very much in, e.g., strength and rheological properties, we have prepared solids of very different mechanical properties just by variation in compression rate. In addition, these metastable phases have stability regions in the phase diagrams only at much higher pressures and temperatures. Therefore, we anticipate that the method of isothermal compression at low temperatures and high compression rates is a tool for the academic and industrial polymorph search with great potential. PMID:20001064

  12. Doubly Distributed Transactions

    2014-08-25

    Doubly Distributed Transactions (D2T) offers a technique for managing operations from a set of parallel clients with a collection of distributed services. It detects and manages faults. Example code with a test harness is also provided

  13. Doubly fed induction machine

    DOEpatents

    Skeist, S. Merrill; Baker, Richard H.

    2005-10-11

    An electro-mechanical energy conversion system coupled between an energy source and an energy load including an energy converter device having a doubly fed induction machine coupled between the energy source and the energy load to convert the energy from the energy source and to transfer the converted energy to the energy load and an energy transfer multiplexer coupled to the energy converter device to control the flow of power or energy through the doubly fed induction machine.

  14. The [NeIV] Lines in High Excitation Gaseous Nebulae.

    PubMed

    Aller, L H

    1970-04-01

    The "forbidden" lines of three times ionized neon are among the most precious indicators of electron temperature and excitation. They are also predicted to be among the strongest lines observed in the far ultraviolet spectra of high excitation nebulae. PMID:16591822

  15. Chemical composition of high-excitation planetaries.

    PubMed

    Aller, L H; Czyzak, S J

    1981-09-01

    Nebular spectral line intensities measured mostly in the optical region, but also in the IR and satellite UV (where possible), are used to derive plasma diagnostics and ionic concentrations n (X(i))/n(H(+)). Then, we use theoretical nebular models to represent as closely as possible certain excitation-sensitive line ratios of HeII/HeI, [OIII]/[OII], and [NeIII]/[NeV]. Also, we try to reproduce the line intensities themselves. These models are used as devices to allow for unobserved ionization stages. Although He, C, and N show significant variations among different nebulae, heavier elements such as O, and probably Ne, S, Cl, and Ar are more nearly constant, suggesting that progenitor stars underwent nuclear transformations in their interiors that affected C and N but not heavier elements. PMID:16593076

  16. Collisional quenching dynamics and reactivity of highly vibrationally excited molecules

    NASA Astrophysics Data System (ADS)

    Liu, Qingnan

    Highly excited molecules are of great importance in many areas of chemistry including photochemistry. The dynamics of highly excited molecules are affected by the intermolecular and intramolecular energy flow between many different kinds of motions. This thesis reports investigations of the collisional quenching and reactivity of highly excited molecules aimed at understanding the dynamics of highly excited molecules. There are several important questions that are addressed. How do molecules behave in collisions with a bath gas? How do the energy distributions evolve in time? How is the energy partitioned for both the donor and bath molecules after collisions? How do molecule structure, molecule state density and intermolecular potential play the role during collisional energy transfer? To answer these questions, collisional quenching dynamics and reactivity of highly vibrationally excited azabenzene molecules have been studied using high resolution transient IR absorption spectroscopy. The first study shows that the alkylated pyridine molecules that have been excited with Evib˜38,800 cm-1 impart less rotational and translational energy to CO2 than pyridine does. Comparison between the alkylated donors shows that the strong collisions are reduced for donors with longer alkyl chains by lowering the average energy per mode but longer alkyl chain have increased flexibility and higher state densities that enhance energy loss via strong collisions. In the second study, the role of hydrogen bonding interactions is explored in collision of vibrationally excited pyridines with H2O. Substantial difference in the rotational energy of H 2O is correlated with the structure of the global energy minimum. A torque-inducing mechanism is proposed that involves directed movement of H 2O between sigma and pi-hydrogen bonding interactions with the pyridine donors. In the third study the dynamics of strong and weak collisions for highly vibrationally excited methylated pyridine

  17. Highly excited and exotic meson spectrum from dynamical lattice QCD

    SciTech Connect

    Jozef Dudek, Robert Edwards, David Richards, Christopher Thomas

    2009-12-01

    Using a new quark-field construction algorithm and a large variational basis of operators, we extract a highly excited isovector meson spectrum on dynamical anisotropic lattices. We show how carefully constructed operators can be used to identify the continuum spin of extracted states. This method allows us to extract, with confidence, excited states, states of high spin and states with exotic quantum numbers, including, for the first time, spin-four states.

  18. The Most Exciting High School in America.

    ERIC Educational Resources Information Center

    Gunby, Phil

    1980-01-01

    Describes the program of the Houston (Texas) High School for Health Professions, which combines traditional high school subjects with health-oriented subjects and with laboratory sessions in patient care and clinical and research areas at Baylor College of Medicine. (Author/IRT)

  19. Evidence for a doubly magic 24O

    NASA Astrophysics Data System (ADS)

    Hoffman, C. R.; Baumann, T.; Bazin, D.; Brown, J.; Christian, G.; Denby, D. H.; DeYoung, P. A.; Finck, J. E.; Frank, N.; Hinnefeld, J.; Mosby, S.; Peters, W. A.; Rogers, W. F.; Schiller, A.; Spyrou, A.; Scott, M. J.; Tabor, S. L.; Thoennessen, M.; Voss, P.

    2009-02-01

    The decay energy spectrum for neutron unbound states in 24O ( Z=8, N=16) has been observed for the first time. The resonance energy of the lowest lying state, interpreted as the 2 level, has been observed at a decay energy above 600 keV. The resulting excitation energy of the 2 level above 4.7 MeV, supplies strong evidence that 24O is a doubly magic nucleus. The data is also consistent with the presence of a second excited state around 5.33 MeV which can be interpreted as the 1 level.

  20. Production of doubly heavy-flavored hadrons at e+e- colliders

    NASA Astrophysics Data System (ADS)

    Zheng, Xu-Chang; Chang, Chao-Hsi; Pan, Zan

    2016-02-01

    Production of the doubly heavy-flavored hadrons (Bc meson, doubly heavy baryons Ξc c , Ξb c , Ξb b , their excited states, and antiparticles of them as well) at e+e- colliders is investigated under two different approaches: LO (leading-order QCD complete calculation) and LL (leading-logarithm fragmentation calculation). The results for the production obtained by the LO and LL approaches, including the angle distributions of the produced hadrons with unpolarized and polarized incoming beams, the behaviors on the energy fraction of the produced doubly heavy-flavored hadron, and comparisons of results between the two approaches, are presented in tables and figures. Thus, characteristics of the production and uncertainties of the approaches are shown precisely, and it is concluded that only if the colliders run at the energies around the Z pole (which may be called the Z factories) and the luminosity of the colliders is as high as possible is the study of the doubly heavy-flavored hadrons completely accessible.

  1. Eucken correction in high-temperature gases with electronic excitation

    SciTech Connect

    Istomin, V. A.; Kustova, E. V. Mekhonoshina, M. A.

    2014-05-14

    In the present paper, thermal conductivity coefficient of high-temperature molecular and atomic gases with excited electronic states is studied using both the kinetic theory algorithm developed by authors earlier and the well known simple expression for the thermal conductivity coefficient proposed by Eucken and generalized by Hirschfelder. The influence of large collision diameters of excited states on the thermal conductivity is discussed. The limit of validity of the Eucken correction is evaluated on the basis of the kinetic theory calculations; an improved model suitable for air species under high-temperature conditions is proposed.

  2. Doubly robust survival trees.

    PubMed

    Steingrimsson, Jon Arni; Diao, Liqun; Molinaro, Annette M; Strawderman, Robert L

    2016-09-10

    Estimating a patient's mortality risk is important in making treatment decisions. Survival trees are a useful tool and employ recursive partitioning to separate patients into different risk groups. Existing 'loss based' recursive partitioning procedures that would be used in the absence of censoring have previously been extended to the setting of right censored outcomes using inverse probability censoring weighted estimators of loss functions. In this paper, we propose new 'doubly robust' extensions of these loss estimators motivated by semiparametric efficiency theory for missing data that better utilize available data. Simulations and a data analysis demonstrate strong performance of the doubly robust survival trees compared with previously used methods. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27037609

  3. Self-excited vibrational viscometer for high-viscosity sensing

    NASA Astrophysics Data System (ADS)

    Yabuno, Hiroshi; Higashino, Keiichi; Kuroda, Masaharu; Yamamoto, Yasuyuki

    2014-09-01

    A method for vibrational viscometers capable of high-viscosity measurements using self-excited oscillations is proposed and assessed both theoretically and experimentally. Such viscometers are well-known for their rapid response and miniaturization. Unlike conventional methods based on Q-value estimations obtained experimentally from the frequency response or resonance curve, we describe the use of self-excited oscillations in viscosity measurements using positive velocity feedback control without relying on the frequency response curve. Such measurements become possible even for high viscosities where the peak of the frequency response curve is ambiguous or does not exist, i.e., the Q-value cannot be estimated from such curves. Furthermore, the validity of the proposed method is experimentally tested using a prototype self-excited viscometer. Downsized oscillators such as micro- or nanoscale cantilevers can be self-excited following a straightforward application of the method. They are expected to enable not only localized monitoring of changes in high viscosity with time but also spatial high-viscosity measurements by the distributed arrangement of the devices.

  4. High frequency excitation of Earth rotation parameters (ERP) from atmosphere.

    NASA Astrophysics Data System (ADS)

    Xie, Boquan; Zheng, Dawei

    1996-06-01

    The data sets of Earth rotation parameters measured by space geodetic techniques and atmospheric angular momentum reduced by the global meteorological data from 1983 through 1992 are used to analyze and study the high frequency excitations of Earth rotation parameters for the length of day and polar motion up to the monthly time scale from the atmosphere. The main results are given.

  5. Complex fragment emission at low and high excitation energy

    SciTech Connect

    Moretto, L.G.

    1986-08-01

    Complex fragment emission has been certified as a compound nucleus process at low energies. An extension of the measurements to heavy ion reactions up to 50 MeV/u shows that most complex fragments are emitted by highly excited compound nuclei formed in incomplete fusion reactions. 12 refs., 26 figs.

  6. Ultrafast electronic processes in highly excited solids: subpicosecond optical studies

    NASA Astrophysics Data System (ADS)

    Petite, Guillaume

    1998-09-01

    Modern short pulse lasers are efficient tools for production of high levels of electronic excitation in solids under irradiation, a state which mimics that of the same materials after the passage of any particle which deposits its energy under the form of electronic excitation. Because they can also be used in a number of optical experiments of charge carriers and defect detection, they offer the unique opportunity of unraveling the ultrafast kinetic aspects of atomic processes induced by the electronic excitation, whose final state is the only aspect accessible in the case of other irradiations. After mentioning a few orders of magnitudes concerning the energy deposition, we will show some examples of recent experiments concerning the mechanisms of irradiation defect creation in insulators. The perspectives opened by recent developments of light sources in a wide range of wavelengths will be finally presented.

  7. High-energy excited states in 98Cd

    NASA Astrophysics Data System (ADS)

    Blazhev, A.; Braun, N.; Grawe, H.; Boutachkov, P.; Nara Singh, B. S.; Brock, T.; Liu, Zh; Wadsworth, R.; Górska, M.; Jolie, J.; Nowacki, F.; Pietri, S.; Domingo-Pardo, C.; Kojouharov, I.; Caceres, L.; Engert, T.; Farinon, F.; Gerl, J.; Goel, N.; Grȩbosz, J.; Hoischen, R.; Kurz, N.; Nociforo, C.; Prochazka, A.; Schaffner, H.; Steer, S.; Weick, H.; Wollersheim, H.-J.; Ataç, A.; Bettermann, L.; Eppinger, K.; Faestermann, T.; Finke, F.; Geibel, K.; Hinke, C.; Gottardo, A.; Ilie, G.; Iwasaki, H.; Krücken, R.; Merchan, E.; Nyberg, J.; Pfützner, M.; Podolyák, Zs; Regan, P.; Reiter, P.; Rinta-Antila, S.; Rudolph, D.; Scholl, C.; Söderström, P.-A.; Warr, N.; Woods, P.

    2010-01-01

    In 98Cd a new high-energy isomeric γ-ray transition was identified, which confirms previous spin-parity assignments and enables for the first time the measurement of the E2 and E4 strength for the two decay branches of the isomer. Preliminary results on the 98Cd high-excitation level scheme are presented. A comparison to shell-model calculations as well as implications for the nuclear structure around 100Sn are discussed.

  8. Elemental abundances in high-excitation planetary nebulae

    NASA Technical Reports Server (NTRS)

    Marionni, P. A.; Harrington, J. P.

    1981-01-01

    The IUE satellite was used to obtain low dispersion spectra of the high excitation planetary nebulae IC 351, IC 2003, NGC 2022, IC 2165, NGC 2440, Hu 1-2, and IC 5217. Numerical modeling was undertaken to determine the chemical composition of these objects with particular emphasis on obtaining elemental carbon and nitrogen abundances. Large variations in the C/N ratio from object to object are suggested.

  9. Highly excited and exotic meson spectroscopy from lattice QCD

    SciTech Connect

    Christopher Thomas

    2011-05-01

    I will discuss recent progress in extracting highly excited and exotic meson spectra using lattice QCD. New results in the light meson sector will be presented, where a combination of techniques have enabled us to confidently identify the spin of extracted states. Highlights include many states with exotic quantum numbers and, for the first time in a lattice QCD calculation, spin-four states. I will conclude with comments on future prospects.

  10. Observation of interference effects via four-photon excitation of highly excited Rydberg states in thermal cesium vapor

    NASA Astrophysics Data System (ADS)

    Kondo, Jorge M.; Šibalić, Nikola; Guttridge, Alexander; Wade, Christopher G.; De Melo, Natalia R.; Adams, Charles S.; Weatherill, Kevin J.

    2015-12-01

    We report on the observation of electromagnetically induced transparency (EIT) and absorption (EIA) of highly excited Rydberg states in thermal Cs vapor using a four-step excitation scheme. The advantage of this four-step scheme is that the final transition to the Rydberg state has a large dipole moment and one can achieve similar Rabi frequencies to two- or three-step excitation schemes using two orders of magnitude less laser power. This scheme enables new applications such as dephasing free Rydberg excitation. The observed lineshapes are in good agreement with simulations based on multilevel optical Bloch equations.

  11. Heavy-ion fission probability calculations at high excitation energy

    SciTech Connect

    D'Arrigo, A.; Giardina, G.; Taccone, A. Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Messina, Messina Istituto di Tecniche Spettroscopiche del Consiglio Nazionale delle Ricerche, Messina )

    1991-12-01

    In the framework of the statistical theory of nuclear reactions we calculated the fission probability {ital P}{sub {ital f}} of the {sup 153}Tb, {sup 158}Er, {sup 159}Dy, {sup 175}Hf, {sup 179}Ta, {sup 186}Os, and {sup 188}Os nuclei with a mass number {ital A}=150--200 produced by heavy-ion reactions. Starting from the spectra of the single-particle levels as determined by Nix and Moeller, and utilizing a formalism we developed, we determined the excitation energy dependence of the effective level density parameters for the fission and the neutron emission channels. The agreement between the fission probability calculations and the experimental data was reached when a nonadiabatic estimate of the collective effects was used to calculate the nuclear level density. In the fission process at high excitation energies induced by ions heavier than the {alpha} particle, an energy dependence of the effective fission barrier has to be used.

  12. High-Frequency Stimulation of Excitable Cells and Networks

    PubMed Central

    Weinberg, Seth H.

    2013-01-01

    High-frequency (HF) stimulation has been shown to block conduction in excitable cells including neurons and cardiac myocytes. However, the precise mechanisms underlying conduction block are unclear. Using a multi-scale method, the influence of HF stimulation is investigated in the simplified FitzhHugh-Nagumo and biophysically-detailed Hodgkin-Huxley models. In both models, HF stimulation alters the amplitude and frequency of repetitive firing in response to a constant applied current and increases the threshold to evoke a single action potential in response to a brief applied current pulse. Further, the excitable cells cannot evoke a single action potential or fire repetitively above critical values for the HF stimulation amplitude. Analytical expressions for the critical values and thresholds are determined in the FitzHugh-Nagumo model. In the Hodgkin-Huxley model, it is shown that HF stimulation alters the dynamics of ionic current gating, shifting the steady-state activation, inactivation, and time constant curves, suggesting several possible mechanisms for conduction block. Finally, we demonstrate that HF stimulation of a network of neurons reduces the electrical activity firing rate, increases network synchronization, and for a sufficiently large HF stimulation, leads to complete electrical quiescence. In this study, we demonstrate a novel approach to investigate HF stimulation in biophysically-detailed ionic models of excitable cells, demonstrate possible mechanisms for HF stimulation conduction block in neurons, and provide insight into the influence of HF stimulation on neural networks. PMID:24278435

  13. High frame rate photoacoustic computed tomography using coded excitation

    NASA Astrophysics Data System (ADS)

    Azuma, Masataka; Zhang, Haichong K.; Kondo, Kengo; Namita, Takeshi; Yamakawa, Makoto; Shiina, Tsuyoshi

    2015-03-01

    Photoacoustic Computed Tomography (PACT) records signals from a wide range of angles to achieve uniform, highresolution images. A high-power laser is generally used for PACT, but the long acquisition time with a single probe is a problem due to the low pulse-repetition frequency (PRF). For PACT, this degrades image resolution and contrast because it is hard to scan with a small step interval. Moreover, in vivo measurement requires a fast image acquisition system to avoid motion artifacts. The problem can be resolved by using a high PRF laser, which provides only weak energy. Averaging measured signals many times can mitigate the low signal-to-noise issue, but the PRF is restricted by the acoustic time of flight, so this is a new source of measurement time increase. Here, we present the coded-excitation approach, which we previously proposed for linear scanning, to increase the PACT frame rate. Coded excitation irradiates temporally encoded pulses and enhances the signal amplitude through decoding. The PRF is thus not restricted to acoustic time of flight. Consequently, acquisition time can be shortened by increasing PRF, and the SNR increases for the same measurement time. To validate the proposed idea, we conducted experiments using a high PRF laser with a revolving motor and compared the performance of coded excitation to that of averaging. Results demonstrated that the contamination of a signal acquired from different angles was negligible, and that the scanning pitch was remarkably improved because the start point of decoding can be set in any code in the periodic sequence.

  14. The remarkably high excitation planetary nebula GC 6537.

    PubMed

    Aller, L H; Hung, S; Feibelman, W A

    1999-05-11

    NGC 6537 is an unusually high excitation point symmetric planetary nebula with a rich spectrum. Its kinematical structures are of special interest. We are here primarily concerned with the high resolution spectrum as revealed by the Hamilton echelle Spectrograph at Lick Observatory (resolution approximately 0.2 A) and supplemented by UV and near-UV data. These extensive data permit a determination of interstellar extinction, plasma diagnostics, and ionic concentrations. The photoionization models that have been used successfully for many planetary nebulae are not entirely satisfactory here. The plasma electron temperature of a photoionization model cannot much exceed 20,000 K, but plasma diagnostics show that regions emitting radiation of highly ionized atoms such as [NeIV] and [NeV] are much hotter, showing that shock excitation must be important, as suggested by the remarkable kinematics of this object. Hence, instead of employing a strict photoionization model, we are guided by the nebular diagnostics, which reveal how electron temperature varies with ionization potential and accommodates density effects. The predictions of the photoionization model may be useful in estimating ionization correction factor. In effect, we have estimated the chemical composition by using both photoionization and shock considerations. PMID:10318889

  15. The remarkably high excitation planetary nebula GC 6537

    PubMed Central

    Aller, Lawrence H.; Hung, Siek; Feibelman, Walter A.

    1999-01-01

    NGC 6537 is an unusually high excitation point symmetric planetary nebula with a rich spectrum. Its kinematical structures are of special interest. We are here primarily concerned with the high resolution spectrum as revealed by the Hamilton echelle Spectrograph at Lick Observatory (resolution ≈ 0.2 Å) and supplemented by UV and near-UV data. These extensive data permit a determination of interstellar extinction, plasma diagnostics, and ionic concentrations. The photoionization models that have been used successfully for many planetary nebulae are not entirely satisfactory here. The plasma electron temperature of a photoionization model cannot much exceed 20,000 K, but plasma diagnostics show that regions emitting radiation of highly ionized atoms such as [Neiv] and [Nev] are much hotter, showing that shock excitation must be important, as suggested by the remarkable kinematics of this object. Hence, instead of employing a strict photoionization model, we are guided by the nebular diagnostics, which reveal how electron temperature varies with ionization potential and accommodates density effects. The predictions of the photoionization model may be useful in estimating ionization correction factor. In effect, we have estimated the chemical composition by using both photoionization and shock considerations. PMID:10318889

  16. Unexpected doubly-magic nucleus.

    SciTech Connect

    Janssens, R. V. F.; Physics

    2009-01-01

    Nuclei with a 'magic' number of both protons and neutrons, dubbed doubly magic, are particularly stable. The oxygen isotope {sup 24}O has been found to be one such nucleus - yet it lies just at the limit of stability.

  17. Excitation and Ionisation dynamics in high-frequency plasmas

    NASA Astrophysics Data System (ADS)

    O'Connell, D.

    2008-07-01

    Non-thermal low temperature plasmas are widely used for technological applications. Increased demands on plasma technology have resulted in the development of various discharge concepts based on different power coupling mechanisms. Despite this, power dissipation mechanisms in these discharges are not yet fully understood. Of particular interest are low pressure radio-frequency (rf) discharges. The limited understanding of these discharges is predominantly due to the complexity of the underlying mechanisms and difficult diagnostic access to important parameters. Optical measurements are a powerful diagnostic tool offering high spatial and temporal resolution. Optical emission spectroscopy (OES) provides non-intrusive access, to the physics of the plasma, with comparatively simple experimental requirements. Improved advances in technology and modern diagnostics now allow deeper insight into fundamental mechanisms. In low pressure rf discharges insight into the electron dynamics within the rf cycle can yield vital information. This requires high temporal resolution on a nano-second time scale. The optical emission from rf discharges exhibits temporal variations within the rf cycle. These variations are particularly strong, in for example capacitively coupled plasmas (CCPs), but also easily observable in inductively coupled plasmas (ICPs), and can be exploited for insight into power dissipation. Interesting kinetic and non-linear coupling effects are revealed in capacitive systems. The electron dynamics exhibits a complex spatio-temporal structure. Excitation and ionisation, and, therefore, plasma sustainment is dominated through directed energetic electrons created through the dynamics of the plasma boundary sheath. In the relatively simple case of an asymmetric capacitively coupled rf plasma the complexity of the power dissipation is exposed and various mode transitions can be clearly observed and investigated. At higher pressure secondary electrons dominate the

  18. High levels of isotope elimination improve precision and allow individual-based measurements of metabolic rates in animals using the doubly labeled water method

    PubMed Central

    Shirai, Masaki; Niizuma, Yasuaki; Yamamoto, Maki; Oda, Emiko; Ebine, Naoyuki; Oka, Nariko; Yoda, Ken

    2015-01-01

    Doubly labeled water (DLW) can be used to measure energy expenditure in free-ranging animals, but questions have been raised about its accuracy in different species or contexts. We investigated whether differences in the extent of isotope elimination affects the precision and accuracy of the DLW method, which can vary according to the experimental design or metabolic rate of the species. Estimated total energy expenditure by the DLW method (TEEdlw) was compared with actual total energy expenditure simultaneously measured via respirometry (TEEresp) in streaked shearwaters Calonectris leucomelas, a pelagic seabird. Subjects were divided into three groups with different experimental conditions: at rest on the ground for 24 h (Group A) or for 48 h (Group B), and at rest on the water for 24 h (Group C). TEEdlw in Group A matched TEEresp, whereas there was an overestimation of TEEdlw in both Groups B and C compared with TEEresp. However, compared with Group A, TEEdlw in Groups B and C had reduced the isotopic analytical variability and thus higher precision. The best regression model (TEEdlw = 1.37 TEEresp − 14.12) showed a high correlation (R2 = 0.82) between TEEdlw and TEEresp and allows a correction factor for field metabolic rates in streaked shearwaters. Our results demonstrate that the commonly made assumption that the DLW method is not appropriate for individual-based estimates may be incorrect in certain circumstances. Although a correction factor may be necessary when using the DLW method to estimate metabolic rate, greater levels of isotope eliminations provides DLW estimates with high precision, which can adequately represent relative individual estimates. Nevertheless, the DLW method, should be used with caution when characterizing interspecies difference of energy expenditures. PMID:26611463

  19. High levels of isotope elimination improve precision and allow individual-based measurements of metabolic rates in animals using the doubly labeled water method.

    PubMed

    Shirai, Masaki; Niizuma, Yasuaki; Yamamoto, Maki; Oda, Emiko; Ebine, Naoyuki; Oka, Nariko; Yoda, Ken

    2015-11-01

    Doubly labeled water (DLW) can be used to measure energy expenditure in free-ranging animals, but questions have been raised about its accuracy in different species or contexts. We investigated whether differences in the extent of isotope elimination affects the precision and accuracy of the DLW method, which can vary according to the experimental design or metabolic rate of the species. Estimated total energy expenditure by the DLW method (TEEdlw) was compared with actual total energy expenditure simultaneously measured via respirometry (TEEresp) in streaked shearwaters Calonectris leucomelas, a pelagic seabird. Subjects were divided into three groups with different experimental conditions: at rest on the ground for 24 h (Group A) or for 48 h (Group B), and at rest on the water for 24 h (Group C). TEEdlw in Group A matched TEEresp, whereas there was an overestimation of TEEdlw in both Groups B and C compared with TEEresp. However, compared with Group A, TEEdlw in Groups B and C had reduced the isotopic analytical variability and thus higher precision. The best regression model (TEEdlw = 1.37 TEEresp - 14.12) showed a high correlation (R(2) = 0.82) between TEEdlw and TEEresp and allows a correction factor for field metabolic rates in streaked shearwaters. Our results demonstrate that the commonly made assumption that the DLW method is not appropriate for individual-based estimates may be incorrect in certain circumstances. Although a correction factor may be necessary when using the DLW method to estimate metabolic rate, greater levels of isotope eliminations provides DLW estimates with high precision, which can adequately represent relative individual estimates. Nevertheless, the DLW method, should be used with caution when characterizing interspecies difference of energy expenditures.

  20. Colloidal quantum dots as probes of excitation field enhancement in photonic antennas.

    PubMed

    Aouani, Heykel; Itzhakov, Stella; Gachet, David; Devaux, Eloïse; Ebbesen, Thomas W; Rigneault, Hervé; Oron, Dan; Wenger, Jérôme

    2010-08-24

    Optical antennas are essential devices to interface light to nanoscale volumes and locally enhance the electromagnetic intensity. Various experimental methods can be used to quantify the antenna amplification on the emission process, yet characterizing the antenna amplification at the excitation frequency solely is a challenging task. Such experimental characterization is highly needed to fully understand and optimize the antenna response. Here, we describe a novel experimental tool to directly measure the antenna amplification on the excitation field independently of the emission process. We monitor the transient emission dynamics of colloidal quantum dots and show that the ratio of doubly to singly excited state photoluminescence decay amplitudes is an accurate tool to quantify the local excitation intensity amplification. This effect is demonstrated on optical antennas made of polystyrene microspheres and gold nanoapertures, and supported by numerical computations. The increased doubly excited state formation on nanoantennas realizes a new demonstration of enhanced light-matter interaction at the nanoscale.

  1. Radiance limits of ceramic phosphors under high excitation fluxes

    NASA Astrophysics Data System (ADS)

    Lenef, Alan; Kelso, John; Zheng, Yi; Tchoul, Maxim

    2013-09-01

    Ceramic phosphors, excited by high radiance pump sources, offer considerable potential for high radiance conversion. Interestingly, thermodynamic arguments suggest that the radiance of the luminescent spot can even exceed that of the incoming light source. In practice, however, thermal quenching and (non-thermal) optical saturation limit the maximum attainable radiance of the luminescent source. We present experimental data for Ce:YAG and Ce:GdYAG ceramics in which these limits have been investigated. High excitation fluxes are achieved using laser pumping. Optical pumping intensities exceeding 100W/mm2 have been shown to produce only modest efficiency depreciation at low overall pump powers because of the short Ce3+ lifetime, although additional limitations exist. When pump powers are higher, heat-transfer bottlenecks within the ceramic and heat-sink interfaces limit maximum pump intensities. We find that surface temperatures of these laser-pumped ceramics can reach well over 150°C, causing thermal-quenching losses. We also find that in some cases, the loss of quantum efficiency with increasing temperature can cause a thermal run-away effect, resulting in a rapid loss in converted light, possibly over-heating the sample or surrounding structures. While one can still obtain radiances on the order of many W/mm2/sr, temperature quenching effects ultimately limit converted light radiance. Finally, we use the diffusion-approximation radiation transport models and rate equation models to simulate some of these nonlinear optical pumping and heating effects in high-scattering ceramics.

  2. Photoelectron Spectroscopy of the Doubly-Charged Anions [MIVO(mnt)2]2- (M=Mo, W; mnt=S2C2(CN)22-): Access to the Ground and Excited States of the [MvO(mnt)2]-Anion

    SciTech Connect

    Waters, Tom; Wang, Xue B.; Yang, Xin; Zhang, L Y.; O'Hair, Richard A.; Wang, Lai S.; Wedd, Anthony G.

    2004-04-21

    Photodetachment photoelectron spectroscopy was used to investigate the electronic structure of the doubly charged complexes [MIVO(mnt)2]2- (M=Mo, W;mnt=1,2 dicyanoethenedithiolato). These dianions are stable in the gas phase and are minimal models for the active sites of the dimethyl sulfoxide reductase family of molybdenum enzymes and of related tungsten enzymes. Adiabatic and vertical electron binding energies for both species were measured, providing detailed information about molecular orbital energy levels of the parent dianions as well as the ground and excited states of the product anions [MvO(mnt)2]. Density functional theory calculations were used to assist assignment of the detachment features.

  3. Observation of the highly excited states of Lanthanum

    SciTech Connect

    Xue, P.; Xu, X. Y.; Huang, W.; Xu, C. B.; Zhao, R. C.; Xie, X. P.

    1997-01-15

    The highly excited states of Lanthanum are studied by means of laser resonance ionization time-of-flight spectrometer. Based on the two-step laser resonance excitation with intermediate state 5d{sup 2}({sup 3}F)6p {sup 2}D{sub 5/2}{sup 0}, three new Rydberg state (RS) series (5d{sup 2}(a{sup 3}F{sub 2})ns, 5d{sup 2}(a{sup 3}F{sub 3})nd and 5d{sup 2}(a{sup 1}D{sub 2})ns) and a number of autoionizing states (AIS) are obtained. Theoretical calculation leads the quantum defects of ns and nd series to the value {delta}s=4.35 and {delta}{sub d}=2.80 respectively, which are very close to the experimental results. The Rydberg state series 5d{sup 2}(a{sup 3}F{sub 2})ns gives the first ionization limit to be 44979.8{+-}0.3 cm{sup -1}, which is an order more accurate than ever.

  4. A Study of Power Systems Stability Enhancement Effects by Excitation Control of Superconducting Generator with High Response Excitation based on Detailed Excitation Circuit Model

    NASA Astrophysics Data System (ADS)

    Wu, Guohong; Shirato, Hideyuki

    SCG (Superconducting Generator) has a superconducting field winding, which leads to many advantages such as small size, high generation efficiency, low impedance, and so on, and be considered as one of the candidates to meet the needs of high stability and high efficiency in the future power system networks. SCG with high response excitation is especially expected to be able to enhance the transient stability of power system by its SMES (Superconducting Magnetic Energy System) effect. The SMES effect of SCG is recognized that its behaviors are dominated by the structures and controls of its excitation system. For this reason, in order to verify exactly how the SMES effect of SCG influences on the power system stability, the electrical circuits of SCG high response excitation are modeled in detail for conducting digital simulation, and its influence on excitation voltage and active power output of SCG are discussed as well. The simulation results with a typical one machine - infinite bus power system model shows that the SMES effect can be certainly obtained when its exciting power is supplied from SCG terminal bus and may considerably lead to an improvement of power system transient stability.

  5. Collisional energy transfer from highly vibrationally excited triatomic molecules

    NASA Astrophysics Data System (ADS)

    Hynes, Robert G.; Sceats, Mark G.

    1989-12-01

    The atom-atom encounter model developed in the accompanying paper [M. G. Sceats, J. Chem. Phys. 91, 0000 (1989)] is applied to the collisional deactivation of highly vibrationally excited triatomic molecules CS2 and SO2 by the monatomic colliders He, Ne, Ar, Kr, and Xe at 300 K. The molecular inputs are a crude normal mode analysis, vibrational frequencies and effective anharmonicities, while the collisional inputs are parameters of the atom-atom potentials. The results for CS2 are compared with the simulations of Bruehl and Schatz and the experiments of Dove, Hippler, and Troe, while those for SO2 are compared with the simulations of Schranz and Troe and the experimental results of Heymann, Hippler, and Troe. Excellent agreement is found with experiment, and the superlinear energy dependence of the average energy transfer is attributed to anharmonicity of the triatomic molecule.

  6. Artificial airglow excited by high-power radio waves.

    PubMed

    Bernhardt, P A; Duncan, L M; Tepley, C A

    1988-11-18

    High-power electromagnetic waves beamed into the ionosphere from ground-based transmitters illuminate the night sky with enhanced airglow. The recent development of a new intensified, charge coupled-device imager made it possible to record optical emissions during ionospheric heating. Clouds of enhanced airglow are associated with large-scale plasma density cavities that are generated by the heater beam. Trapping and focusing of electromagnetic waves in these cavities produces accelerated electrons that collisionally excite oxygen atoms, which emit light at visible wavelengths. Convection of plasma across magnetic field lines is the primary source for horizontal motion of the cavities and the airglow enhancements. During ionospheric heating experiments, quasi-cyclic formation, convection, dissipation and reappearance of the cavites comprise a major source of long-term variability in plasma densities during ionospheric heating experiments.

  7. High temperature electronic excitation and ionization rates in gases

    NASA Technical Reports Server (NTRS)

    Hansen, Frederick

    1991-01-01

    The relaxation times for electronic excitation due to electron bombardment of atoms was found to be quite short, so that electron kinetic temperature (T sub e) and the electron excitation temperature (T asterisk) should equilibrate quickly whenever electrons are present. However, once equilibrium has been achieved, further energy to the excited electronic states and to the kinetic energy of free electrons must be fed in by collisions with heavy particles that cause vibrational and electronic state transitions. The rate coefficients for excitation of electronic states produced by heavy particle collision have not been well known. However, a relatively simple semi-classical theory has been developed here which is analytic up to the final integration over a Boltzmann distribution of collision energies; this integral can then be evaluated numerically by quadrature. Once the rate coefficients have been determined, the relaxation of electronic excitation energy can be evaluated and compared with the relaxation rates of vibrational excitation. Then the relative importance of these two factors, electronic excitation and vibrational excitation by heavy particle collision, on the transfer of energy to free electron motion, can be assessed.

  8. Ionization of highly excited helium atoms in an electric field

    SciTech Connect

    van de Water, W.; Mariani, D.R.; Koch, P.M.

    1984-11-01

    We present detailed measurements of ionization of highly excited triplet helium atoms in a static electric field. The atoms were prepared in states with energy E close to the saddle-point threshold E = -2(F(a.u.))/sup 1/2/. The electric field F was sufficiently strong for the states to be characterized by total spin S and absolute value of the magnetic quantum number M/sub L/. For M/sub L/ = 0 states the experiments measured ionization properties of adiabatic states. In another case, Vertical BarM/sub L/Vertical Bar = 2, they predominantly measured those of diabatic states. In both cases the ionization rate was found to be a highly nonmonotonic function of the field strength. The observations are analyzed in terms of a theory of the helium density of states in an electric field. A companion paper (D. A. Harmin, Phys. Rev. A 30, 2413 (1984)) develops in detail the general theory, which uses quantum defects to parametrize the effect of the core interaction. The agreement between measured and calculated ionization curves is good, indicating that the field ionization of a nonhydrogenic atom can now be understood in a detailed, quantitative, and predictive sense.

  9. Properties of Shell-Model Wavefunctions at High Excitation Energies

    NASA Astrophysics Data System (ADS)

    Frazier, Njema Jioni

    Within the framework of the nuclear shell model with a realistic residual hamiltonian one can obtain the exact solution of the many-body problem. This makes it possible to study the interrelation between regular and chaotic features of dynamics in a generic many-body system with strong interaction. As an important application, we analyse the fragmentation of simple configurations as a function of excitation energy and interaction strength and examine the transition strengths induced by simple operators as a function of excitation energy. The analysis is performed for two systems; that of 12 valence particles in the sd-shell, or 28Si, and that of 8 valence particles in the sd-shell, or 24Mg. For the system of 12 valence particles in the sd-shell, we examine the fragmentation of shell-model basis states. For the system of 8 valence nucleons in the sd-shell, we examine the fragmentation associated with single-nucleon transfer and Gamow-Teller transitions. For the fragmentation of basis states, we use our statistics to establish the generic shape of the strength function distribution in the region of strong mixing. For the realistic interaction, the strength function distribution is close to Gaussian in the central part of the energy spectra. The width of the distribution is larger than predicted by Fermi's golden rule (4). We then take this one step further and examine the strength distributions associated with the one-nucleon transfer operator, aλ†, and the Gamow-Teller (GT) operator, Σλλ'(σμ τ±) λλ'aλ†a λ'. The spectroscopic factor, which is proportional to the square of the matrix element for the aλ† operator, is the simplest quantity used in predicting experimental observables. In our discussion of Gamow-Teller transitions, we examine both the GT strength function distribution and the values of total strength B(GT). For all the cases we examine, we take advantage of the reliability of our model for low-lying levels and our statistics to explore

  10. Brushless exciters using a high temperature superconducting field winding

    SciTech Connect

    Garces, Luis Jose; Delmerico, Robert William; Jansen, Patrick Lee; Parslow, John Harold; Sanderson, Harold Copeland; Sinha, Gautam

    2008-03-18

    A brushless exciter for a synchronous generator or motor generally includes a stator and a rotor rotatably disposed within the stator. The rotor has a field winding and a voltage rectifying bridge circuit connected in parallel to the field winding. A plurality of firing circuits are connected the voltage rectifying bridge circuit. The firing circuit is configured to fire a signal at an angle of less than 90.degree. or at an angle greater than 90.degree.. The voltage rectifying bridge circuit rectifies the AC voltage to excite or de-excite the field winding.

  11. Subwavelength acoustic focusing by surface-wave-resonance enhanced transmission in doubly negative acoustic metamaterials

    SciTech Connect

    Zhou, Xiaoming; Badreddine Assouar, M. Oudich, Mourad

    2014-11-21

    We present analytical and numerical analyses of a yet unseen lensing paradigm that is based on a solid metamaterial slab in which the wave excitation source is attached. We propose and demonstrate sub-diffraction-limited acoustic focusing induced by surface resonant states in doubly negative metamaterials. The enhancement of evanescent waves across the metamaterial slab produced by their resonant coupling to surface waves is evidenced and quantitatively determined. The effect of metamaterial parameters on surface states, transmission, and wavenumber bandwidth is clearly identified. Based on this concept consisting of a wave source attached on the metamaterial, a high resolution of λ/28.4 is obtained with the optimum effective physical parameters, opening then an exciting way to design acoustic metamaterials for ultrasonic focused imaging.

  12. Collisional excitation of the highly excited hydrogen atoms in the dipole form of the semiclassical impact parameter and Born approximations

    NASA Technical Reports Server (NTRS)

    Omidvar, K.

    1971-01-01

    Expressions for the excitation cross section of the highly excited states of the hydrogenlike atoms by fast charged particles have been derived in the dipole approximation of the semiclassical impact parameter and the Born approximations, making use of a formula for the asymptotic expansion of the oscillator strength of the hydrogenlike atoms given by Menzel. When only the leading term in the asymptotic expansion is retained, the expression for the cross section becomes identical to the expression obtained by the method of the classical collision and correspondence principle given by Percival and Richards. Comparisons are made between the Bethe coefficients obtained here and the Bethe coefficients of the Born approximation for transitions where the Born calculation is available. Satisfactory agreement is obtained only for n yields n + 1 transitions, with n the principal quantum number of the excited state.

  13. Collective, stochastic and nonequilibrium behavior of highly excited hadronic matter

    SciTech Connect

    Carruthers, P.

    1983-01-01

    We discuss selected problems concerning the dynamic and stochasticc behavior of highly excited matter, particularly the QCD plasma. For the latter we consider the equation of state, kinetics, quasiparticles, flow properties and possible chaos and turbulence. The promise of phase space distribution functions for covariant transport and kinetic theory is stressed. The possibility and implications of a stochastic bag are spelled out. A simplified space-time model of hadronic collisions is pursued, with applications to A-A collisions and other matters. The domain wall between hadronic and plasma phase is of potential importance: its thickness and relation to surface tension are noticed. Finally we reviewed the recently developed stochastic cell model of multiparticle distributions and KNO scaling. This topic leads to the notion that fractal dimensions are involved in a rather general dynamical context. We speculate that various scaling phenomena are independent of the full dynamical structure, depending only on a general stochastic framework having to do with simple maps and strange attractors. 42 references.

  14. High-Frequency Excitation of a Plane Wake

    NASA Technical Reports Server (NTRS)

    Cain, Alan B.; Rogers, Michael M.

    2000-01-01

    In the early 1990's, Glezer and his co-workers at Georgia Tech made a startling discovery. They found that forcing at frequencies too high to directly affect the production scales led to a dramatic alteration in the development of a turbulent shear layer. An experimental study of this phenomenon is presented in Wiltse and Glezer. They used piezoelectric actuators located near the jet exit plane to force the shear layers of a square low-speed jet. The actuators were driven at a high frequency in the Kolmogorov inertial subrange, much higher than the frequencies associated with the large-scale motion (where the turbulent energy is produced and located) but much lower than those associated with the Kolmogorov scale (where the turbulent energy is dissipated). Measurements of the shear-layer turbulence showed that direct excitation of small-scale motion by high-frequency forcing led to an increase in the turbulent dissipation of more than an order of magnitude in the initial region of the shear layer! The turbulent dissipation gradually decreased with downstream distance but remained above the corresponding level for the unforced flow at all locations examined. The high-frequency forcing increased the turbulent kinetic energy in the initial region near the actuators, but the kinetic energy decreased quite rapidly with downstream distance, dropping to levels that were a small fraction of the level for the unforced case. Perhaps most importantly from the present standpoint, the high-frequency forcing significantly decreased the energy in the large-scale motion, increasingly so with downstream distance. Wiltse and Glezer interpreted this behavior as an enhanced transfer of energy from the large scales to the small scales. The initial work by Wiltse and Glezer has expanded into other applications. To explore the potential of high-frequency forcing for active acoustic suppression, in 1998 the first author proposed a set of experiments involving an edge tone shear layer and

  15. Electron impact excitation of highly charged sodium-like ions

    NASA Technical Reports Server (NTRS)

    Blaha, M.; Davis, J.

    1978-01-01

    Optical transition probabilities and electron collision strengths for Ca X, Fe XVI, Zn XX, Kr XXVI and Mo XXXII are calculated for transitions between n equal to 3 and n equal to 4 levels. The calculations neglect relativistic effects on the radial functions. A semi-empirical approach provides wave functions of the excited states; a distorted wave function without exchange is employed to obtain the excitation cross sections. The density dependence of the relative intensities of certain emission lines in the sodium isoelectronic sequence is also discussed.

  16. Shape changes and isospin purity in highly excited light mass nuclei

    SciTech Connect

    Kicinska-Habior, M. |; Snover, K.A.; Behr, J.A.; Gossett, C.A.; Gundlach, J.H.; Drebi, Z.M.; Kaplan, M.S.; Wells, D.P.

    1993-11-01

    The statistical decay of the Giant Dipole Resonance built on a highly excited states of light-mass nuclei was studied in inclusive experiments. Results of the search for a shape change of hot, fast-rotating {sup 45}Sc and the test of the isospin purity at high excitation in {sup 28}Si and {sup 26}Al are reported.

  17. Aspects of data on the breakup of highly excited nuclei

    SciTech Connect

    Warwick, A.I.; Wieman, H.H.; Gutbrod, H.H.; Ritter, H.G.; Stelzer, H.; Weik, F.; Kaufman, S.B.; Steinberg, E.P.; Wilkins, B.D.

    1983-05-01

    There is an awakening of theoretical interest in the mechanisms by which nuclear fragments (4 less than or equal to A less than or equal to 150) are produced in violent collisions of heavy ions. With this in mind we review some aspects of the available experimental data and point out some challenging features against which to test the models. The concept of evaporation is tremendously powerful when applied to pieces of nuclei of low excitation (1 or 2 MeV/u). Current interest focuses on higher excitations, at the point where the binding energy of the system vanishes. This is the transition from liquid nuclei to a gas of nucleons, and it may be that the critical phenomena that certainly exist in infinite nuclear matter will be manifest in finite nuclei under these conditions.

  18. Superconductivity and charge transfer excitations in high T c superconductors

    NASA Astrophysics Data System (ADS)

    Balseiro, C. A.; Alascio, B.; Gagliano, E.; Rojo, A.

    We present some numerical results to show that in a simple model which includes Cu3d and O 2p orbitals together with inter and intra atomic correlations pairing between holes can occur due to charge transfer excitations. We present also a simple approximation to derive an effective Hamiltonian containing an interaction between particles which is attractive for some values of the different microscopic parameters. Nous présentons des résultats numériques qui montrent que dans un modèle simple, incluant les orbitales 3d du cuivre et 2p de l'oxygène, avec une interaction coulombienne interatomique et intra-atomique, les trous peuvent s'apparier à cause des excitations de transfert de charge. Nous présentons aussi une approximation simple pour obtenir un Hamiltonien effectif contenant une interaction entre particules qui peut être attractive pour certaines valeurs des paramètres microscopiques.

  19. High resolution photoionisation spectroscopy of vibrationally excited Ar · NO

    NASA Astrophysics Data System (ADS)

    Monti, O. L. A.; Cruse, H. A.; Softley, T. P.; Mackenzie, S. R.

    2001-01-01

    Mass-analysed threshold ionisation (MATI) spectra of the Ar · NO complex have been obtained for the first time. These spectra have been used to determine unambiguously the nature of three bands detected by resonance-enhanced multiphoton ionisation (REMPI) spectroscopy via the à state of Ar · NO. The features are shown to originate from vibrationally excited states of Ar · NO in its electronic ground state. The assignment is in agreement with recent theoretical calculations.

  20. Plasmon excitations in layered high-Tc cuprates

    NASA Astrophysics Data System (ADS)

    Greco, Andrés; Yamase, Hiroyuki; Bejas, Matías

    2016-08-01

    Motivated by the recent resonant inelastic x-ray scattering (RIXS) experiment for the electron-doped cuprates Nd2 -xCexCuO4 with x ≈0.15 , we compute the density-density correlation function in the t -J model on a square lattice by including interlayer hopping and the long-range Coulomb interaction. We find that collective charge excitations are realized not inside the particle-hole continuum, but above the continuum as plasmons. The plasmon mode has a rather flat dispersion near the in-plane momentum q∥=(0 ,0 ) with a typical excitation energy of the order of the intralayer hopping t when the out-of-plane momentum qz is zero. However, when qz becomes finite, the plasmon dispersion changes drastically near q∥=(0 ,0 ) , leading to a strong dispersive feature with an excitation gap scaled by the interlayer hopping tz. We discuss the mode recently observed by RIXS near q∥=(0 ,0 ) in terms of the plasmon mode with a finite qz.

  1. Parametric excitation of high-mode oscillations for a non-linear telegraph equation

    SciTech Connect

    Kolesov, Andrei Yu; Rozov, Nikolai Kh

    2000-08-31

    The problem of parametric excitation of high-mode oscillations is solved for a non-linear telegraph equation with a parametric external excitation and small diffusion. The equation is considered on a finite (spatial) interval with Neumann boundary conditions. It is shown that under a proper choice of parameters of the external excitation this boundary-value problem can have arbitrarily many exponentially stable solutions that are periodic in time and rapidly oscillate with respect to the spatial variable.

  2. Hidden Fermionic Excitation Boosting High-Temperature Superconductivity in Cuprates.

    PubMed

    Sakai, Shiro; Civelli, Marcello; Imada, Masatoshi

    2016-02-01

    The dynamics of a microscopic cuprate model, namely, the two-dimensional Hubbard model, is studied with a cluster extension of the dynamical mean-field theory. We find a nontrivial structure of the frequency-dependent self-energies, which describes an unprecedented interplay between the pseudogap and superconductivity. We show that these properties are well described by quasiparticles hybridizing with (hidden) fermionic excitations, emergent from the strong electronic correlations. The hidden fermion enhances superconductivity via a mechanism distinct from a conventional boson-mediated pairing, and originates the normal-state pseudogap. Though the hidden fermion is elusive in experiments, it can solve many experimental puzzles.

  3. Hidden Fermionic Excitation Boosting High-Temperature Superconductivity in Cuprates.

    PubMed

    Sakai, Shiro; Civelli, Marcello; Imada, Masatoshi

    2016-02-01

    The dynamics of a microscopic cuprate model, namely, the two-dimensional Hubbard model, is studied with a cluster extension of the dynamical mean-field theory. We find a nontrivial structure of the frequency-dependent self-energies, which describes an unprecedented interplay between the pseudogap and superconductivity. We show that these properties are well described by quasiparticles hybridizing with (hidden) fermionic excitations, emergent from the strong electronic correlations. The hidden fermion enhances superconductivity via a mechanism distinct from a conventional boson-mediated pairing, and originates the normal-state pseudogap. Though the hidden fermion is elusive in experiments, it can solve many experimental puzzles. PMID:26894730

  4. Activators of photoluminescence in calcite: evidence from high-resolution, laser-excited luminescence spectroscopy

    USGS Publications Warehouse

    Pedone, V.A.; Cercone, K.R.; Burruss, R.C.

    1990-01-01

    Laser-excited luminescence spectroscopy of a red-algal, biogenic calcite and a synthetic Mn-calcite can make the distinction between organic and trace-element activators of photoluminescence. Organic-activated photoluminescence in biogenic calcite is characterized by significant peak shifts and increasing intensity with shorter-wavelength excitation and by significant decreases in intensity after heating to ??? 400??C. In contrast, Mn-activated photoluminescence shows no peak shift, greatest intensity under green excitation and limited changes after heating. Examination of samples with a high-sensitivity spectrometer using several wavelengths of exciting light is necessary for identification of photoluminescence activators. ?? 1990.

  5. Designing and modeling doubly porous polymeric materials

    NASA Astrophysics Data System (ADS)

    Ly, H.-B.; Le Droumaguet, B.; Monchiet, V.; Grande, D.

    2015-07-01

    Doubly porous organic materials based on poly(2-hydroxyethyl methacrylate) are synthetized through the use of two distinct types of porogen templates, namely a macroporogen and a nanoporogen. Two complementary strategies are implemented by using either sodium chloride particles or fused poly(methyl methacrylate) beads as macroporogens, in conjunction with ethanol as a porogenic solvent. The porogen removal respectively allows for the generation of either non-interconnected or interconnected macropores with an average diameter of about 100-200 μm and nanopores with sizes lying within the 100 nm order of magnitude, as evidenced by mercury intrusion porosimetry and scanning electron microscopy. Nitrogen sorption measurements evidence the formation of materials with rather high specific surface areas, i.e. higher than 140 m2.g-1. This paper also addresses the development of numerical tools for computing the permeability of such doubly porous materials. Due to the coexistence of well separated scales between nanopores and macropores, a consecutive double homogenization approach is proposed. A nanoscopic scale and a mesoscopic scale are introduced, and the flow is evaluated by means of the Finite Element Method to determine the macroscopic permeability. At the nanoscopic scale, the flow is described by the Stokes equations with an adherence condition at the solid surface. At the mesoscopic scale, the flow obeys the Stokes equations in the macropores and the Darcy equation in the permeable polymer in order to account for the presence of the nanopores.

  6. The Effects of Various Design Parameters on the Free Vibration of Doubly Curved Composite Sandwich Panels

    NASA Astrophysics Data System (ADS)

    CUNNINGHAM, P. R.; WHITE, R. G.; AGLIETTI, G. S.

    2000-02-01

    Sandwich panels have a very high stiffness to weight ratio, which makes them particularly useful in the aerospace industry where carbon fibre reinforced plastics and lightweight honeycomb cores are being used in the construction of floor panels, fairings and intake barrel panels. In the latter case, the geometry of the panels can be considered doubly curved. This paper presents an introduction to an ongoing study investigating the dynamic response prediction of acoustically excited composite sandwich panels which have double curvature. The final objective is to assess and hopefully produce an up to date set of acoustic fatigue design guidelines for this type of structure. The free vibration of doubly curved composite honeycomb sandwich panels is investigated here, both experimentally and theoretically, the latter using a commerically available finite element package. The design and manufacture of three test panels is covered before presenting experimental results for the natural frequencies of vibration with freely supported boundary conditions. Once validated against the experimental results, the theoretical investigation is extended to study the effects of changing radii of curvature, orthotropic properties of the core, and ply orientation on the natural frequencies of vibration of rectangular panels with various boundary conditions. The results from the parameter studies show curve veering, particularly when studying the effect of changing radii and ply orientation, however, it is not clear whether this phenomenon is due to the approximation method used or occurs in the physical system.

  7. Delayed fluorescence during the deactivation of highly excited triplet states

    SciTech Connect

    Skvortsov, V.I.; Alfimov, M.V.

    1987-06-01

    It has been suggested that the T state may be not only an electron donor but an acceptor, i.e., it may give a charge transfer state in a photoreduction reaction: A(T) + M ..-->.. /sup 3/(A/sup .-/M/sup +./). In this connection, it may be assumed that the quenching may also be connected with the nonradiative deactivation of excitation energy in charge transfer states (A/sup .-/M/sup +./). Aromatic molecules are characterized by an extremely low quantum yield for intramolecular intersystem crossing. However, in charge-transfer states the efficiency of intersystem crossing may be enhanced. The authors have investigated the laws governing DF in conditions where the deactivation of T states occurs. The systems studied were frozen (77 K) solutions of the aromatic additives naphthalene, diphenyl, and chrysene in toluene, MCH, and ethanol.

  8. Intersystem crossing from highly excited states. rhodamine 6G

    SciTech Connect

    Ryl'kov, V.V.; Cheshev, E.A.

    1985-09-01

    The authors carried out an investigation of ethanolic solutions of Rhodamine 6G (R6G) at 20 C by laser flash photolysis. The excitation of dilute (3 /SUP ./ 10/sup -5/ M) solutions of R6G with an initial optical density of 1.5 up to an intensity of 100 MW/cm/sup 2/ resulted in only weak triplet-triplet absorption. The introduction of additions of lithium chloride or lithium bromide in 0.1 M concentrations into a solution of R6G (3.10/sup -5/ M) resulted in the appearance of induced absorption and the introduction of an addition of lithium nitrate in the same concentration into the solution did not result in enhancement of triplet-triplet absorption.

  9. Quenching of highly rotationally excited HCl in collisions with He

    SciTech Connect

    Yang, Benhui; Stancil, P. C. E-mail: stancil@physast.uga.edu

    2014-03-10

    We report rotational quenching cross sections and rate coefficients of HCl due to collisions with He. The close-coupling method and the coupled-states approximation are applied in quantum-mechanical scattering calculations of state-to-state cross sections for HCl with initial rotational levels up to j = 20 for kinetic energies from 10{sup –5} to 15,000 cm{sup –1}. State-to-state rate coefficients for temperatures between 0.1 and 3000 K are also presented. Comparison of the present rate coefficients with previous results reported in the literature for lowly excited rotational levels shows reasonable agreement. Small differences are attributed to the differences in the interaction potential energy surfaces. The uncertainty in the computed cross sections and rate coefficients is estimated by varying the potential well depth. Applications of current results to astrophysical systems are also briefly discussed.

  10. Core solutions of rigidly rotating spiral waves in highly excitable media.

    PubMed

    Cai, Mei-Chun; Pan, Jun-Ting; Zhang, Hong

    2014-02-01

    Analytical spiral wave solutions for reaction-diffusion equations play an important role in studying spiral wave dynamics. In this paper, we focus on such analytical solutions in the case of highly excitable media. We present numerical evidence that, for rigidly rotating spiral waves in highly excitable media, the species values in the spiral core region do harmonic oscillations but not relaxation ones, and their amplitudes grow linearly with the distance from the rotation center. An analytical solution is proposed to describe such spiral wave dynamics, and the quantitative comparisons between the numerical results and the analytical solutions show that the proposed spiral core solution works well in highly excitable media. PMID:25353558

  11. Doubly heavy baryon spectra guided by lattice QCD

    NASA Astrophysics Data System (ADS)

    Garcilazo, H.; Valcarce, A.; Vijande, J.

    2016-10-01

    This paper provides results for the ground state and excited spectra of three-flavored doubly heavy baryons, b c n and b c s . We take advantage of the spin-independent interaction recently obtained to reconcile the lattice SU(3) QCD static potential and the results of nonperturbative lattice QCD for the triply heavy baryon spectra. We show that the spin-dependent potential might be constrained on the basis of nonperturbative lattice QCD results for the spin splittings of three-flavored doubly heavy baryons. Our results may also represent a challenge for future lattice QCD work, because a smaller lattice error could help in distinguishing between different prescriptions for the spin-dependent part of the interaction. Thus, by comparing with the reported baryon spectra obtained with parameters estimated from lattice QCD, one can challenge the precision of lattice calculations. The present work supports a coherent description of singly, doubly and triply heavy baryons with the same Cornell-like interacting potential. The possible experimental measurement of these states at LHCb is an incentive for this study.

  12. Doubly-Tagged D

    NASA Astrophysics Data System (ADS)

    Prabhakar, Ernest Navaroop

    1995-01-01

    The D_{s} is a pseudoscalar meson composed of two second generation quarks, the heavy charm and the light strange. The bulk of our knowledge of the D_{s} comes from secondary production via B decays. These experiments have high statistics but are poorly suited to absolute branching fraction or production cross-section measurements. The best way to perform those is to use double-tagging of threshold pair production. Unfortunately, there is no strong resonance near D_{s } threshold, making it difficult to obtain sufficient statistics. This thesis makes use of the {cal L} = 22.8 +/- 0.6 {rm pb}^ {-1} integrated luminosity collected by the Beijing Spectrometer from the Beijing Electron-Positron Collider at 4.03 GeV. This energy was chosen because the coupled-channel model of Eichten et al. predicts an enhancement there of the D_sp{s}{+}D _sp{s}{-} cross section to somewhat below 1 nb. We attempt to fully reconstruct hadronic and semileptonic D_{s} pairs from six-prong events not containing any photons. We combine the chi^2 from kinematic fitting and particle identification to form a single value, the joint confidence level, for each event. Using this in the analysis yields five hadronic events, with multiple combinations per event. Since the D_{s} principally decays to resonant moves, we preferentially select those combinations which lead to resonant two-body masses. This gives us a signal containing 7 resonant decays and 3 non-resonant K^+K^-pi^+ decays. We use Monte Carlo efficiencies and knowledge of the ratio B(D_sp{s}{+} to | K^{*0}K^+)/B(D _sp{s}{+} to K^+K ^-pi^+) to estimate the production rates represented by these tags. We perform a likelihood analysis using those numbers, together with the absolute branching fractions, to obtain a value of sigma(e^+e^- to D_sp{s}{+}D_sp{s }{-}) at 4.03 GeV = 0.53 _sp{-0.20}{+0.28}_sp{ -0.09}{+0.07}nb, one sigma below the coupled channel model. Using only relative branching fractions, we fit to a value for the ratio B(D _sp

  13. Revised and extended level scheme of the doubly-odd nucleus {sup 188}Ir

    SciTech Connect

    Jungclaus, A.; Modamio, V.; Egido, J. L.; Fernandez, M. A.; Schwengner, R.; Algora, A.; Bazzacco, D.; Lenzi, S.; Marginean, N.; Ur, C. A.; Escrig, D.; Fraile, L. M.; Martinez, T.; Napoli, D. R.

    2008-02-15

    High-spin states in the doubly odd Z=77 nucleus {sup 188}Ir were studied using the reaction {sup 186}W({sup 7}Li, 5n) at 59 MeV and the GASP spectrometer for {gamma}-ray detection. The level structures recently suggested to be built on the known 4.1(3) ms isomeric state of this nucleus have been considerably revised and extended and an isomer with a lifetime of 17.7(2) ns has been identified within the main decay sequence. In addition two rotational bands built on low spin states below the ms isomer have been observed for the first time. The basic features of the excitation scheme of {sup 188}Ir are discussed within the Hartree-Fock-Bogoliubov theory within the Lipkin-Nogami approach with the finite-range density-dependent Gogny force.

  14. Sympathetic cooling of laser-produced doubly charged ions in a few-ion crystal

    SciTech Connect

    Kwapien, T.; Eichmann, U.; Sandner, W.

    2007-06-15

    We present experimental results in which single Ca{sup +} ions in a chain of laser cooled Ca{sup +} ions are further ionized by means of an intense short pulse laser. The ions are trapped in a linear Paul trap, which is instantaneously loaded by ions from a laser-produced ablation plasma. Due to sympathetic cooling the doubly charged ions are held in place. We study and characterize linear few-ion crystals with mixed charges by applying a radio frequency field, which excites the center of mass (c.m.) and breathing modes of different configurations. From the position shift of laser cooled ions initiated through the higher charge state we can deduce the charge of the nonfluorescing ion. This information might be used as an intensity probe for high intensity lasers.

  15. Note: Excited State Studies of Ozone using State-Specific Multireference Coupled Cluster Methods

    SciTech Connect

    Bhaskaran-Nair, Kiran; Kowalski, Karol

    2012-12-07

    Vertical excitation energies obtained with state-specific multi-reference coupled cluster (MRCC) methods are reported for the ozone molecule. Using state-specific MRCC non-iterative methods with singles, doubles, and non-iterative triples (MRCCSD(T)) we obtain 4.40 eV for the challenging doubly excited 21A1 state when using a reliable model space. This estimate is in good agreement with experiment (4.5 eV). We also compare our MRCC results with the excitation energies obtained with high-order equation-of-motion coupled cluster methods

  16. Proceedings of the 1984 workshop on high-energy excitations in condensed matter. Volume II

    SciTech Connect

    Silver, R.N.

    1984-12-01

    This volume covers electronic excitations, momentum distributions, high energy photons, and a wrap-up session. Abstracts of individual items from the conference were prepared separately for the data base. (GHT)

  17. The Doubly Exceptional Child: A Principal's Dilemma.

    ERIC Educational Resources Information Center

    Kesner, Rebecca J., Ed.

    2002-01-01

    This document contains two articles concerned with doubly exceptional children and gifted education. In "The Doubly Exceptional Child: A Principal's Dilemma," (Carol J. Mills and Linda E. Brody), such children do not fit into the usual categories for sorting children because their gifts and disabilities often mask each other. Suggestions are…

  18. Nonlinear response of a clamped beam and plate to high levels of excitation

    NASA Astrophysics Data System (ADS)

    Wolfe, Howard F.; White, Robert G.

    Acoustic fatigue failure in aerospace structures has been a concern for many years. New prediction techniques are needed for the new materials and structural concepts of interest and higher sound pressure levels encountered for the hypersonic flight regime. The objective of this program of work is to improve the fundamental understanding of the nonlinear behavior of beams and plates excited from low to high levels of excitation. Experiments have been conducted utilizing a clamped-clamped (C-C) beam statically tested and shaker driven at increasing levels of excitation. Similarly, a C-C-C-C plate was acoustically excited in a progressive wave tube. The total strains and the components, bending and axial, were measured for increasing levels of excitation. The bending strain response modes induced exhibited a peak broadening and frequency increase with an increase in excitation levels. The bending strain amplitudes were slightly less than the total strains measured. While the axial strains increased with increasing excitation levels, they did not increase as rapidly as expected. The static test resulted in a linear relationship between the strain and the loads over the level of interest. The dynamic tests resulted in a nonlinear relationship between the response strains and the excitation levels.

  19. Core-level excitation and fragmentation of chlorine dioxide

    NASA Astrophysics Data System (ADS)

    Flesch, R.; Plenge, J.; Rühl, E.

    2006-03-01

    Inner-shell excitation and fragmentation of chlorine dioxide (OClO) in the Cl 2p- and O 1s-excitation regime is reported. The electronic structure of the element-selectively excited radical is studied by X-ray absorption and total cation yields. A comparison of both approaches allows us to estimate the absolute photoionization cross-section and the ionization yield near the Cl 2p- and O 1s-absorption edges. The latter quantity is characteristically enhanced in core-ionization continua. We observe below both core-absorption edges intense core-to-valence-transitions. These are assigned in comparison with related work on core-excited sulfur dioxide. These results give clear evidence that the highest molecular orbital of OClO is half-filled. High-resolution spectra recorded in the Cl 2p-regime show evidence for Rydberg transitions. The extrapolation of the term values of the low-lying Rydberg states allows us to derive the Cl 2p-ionization energy of OClO. Fragmentation of core-excited OClO is reported. Photoelectron-photoion-coincidence (PEPICO) spectra are recorded, indicating that singly and doubly charged fragments are formed. Fission of the doubly and multiply charged OClO leads to singly charged fragments. These are measured by photoion-photoion-coincidence (PIPICO) spectra, where characteristic changes in intensity of the fission channels in the Cl 2p- and O 1s-continuum are observed.

  20. Doping dependence of spin excitations and its correlations with high-temperature superconductivity in iron pnictides.

    PubMed

    Wang, Meng; Zhang, Chenglin; Lu, Xingye; Tan, Guotai; Luo, Huiqian; Song, Yu; Wang, Miaoyin; Zhang, Xiaotian; Goremychkin, E A; Perring, T G; Maier, T A; Yin, Zhiping; Haule, Kristjan; Kotliar, Gabriel; Dai, Pengcheng

    2013-01-01

    High-temperature superconductivity in iron pnictides occurs when electrons and holes are doped into their antiferromagnetic parent compounds. Since spin excitations may be responsible for electron pairing and superconductivity, it is important to determine their electron/hole-doping evolution and connection with superconductivity. Here we use inelastic neutron scattering to show that while electron doping to the antiferromagnetic BaFe₂As₂ parent compound modifies the low-energy spin excitations and their correlation with superconductivity (<50 meV) without affecting the high-energy spin excitations (>100 meV), hole-doping suppresses the high-energy spin excitations and shifts the magnetic spectral weight to low-energies. In addition, our absolute spin susceptibility measurements for the optimally hole-doped iron pnictide reveal that the change in magnetic exchange energy below and above T(c) can account for the superconducting condensation energy. These results suggest that high-T(c) superconductivity in iron pnictides is associated with both the presence of high-energy spin excitations and a coupling between low-energy spin excitations and itinerant electrons.

  1. Brushless generation with cascaded doubly fed machines

    NASA Astrophysics Data System (ADS)

    Ortmeyer, T. H.; Borger, W. U.

    The solid state converter used by the system operates at a fraction of the system power and frequency. What is more, the system operates without hydraulics. The fundamental characteristics of operation are discussed. Attention is given to the choice of optimum speeds and pole numbers for a given speed range. It is shown that two discrete operating modes exist for this type of system, namely subsynchronous and supersynchronous. System analysis is treated, and particular power, var, and frequency requirements for a 1.5:1 speed range system are presented. Cascaded doubly fed machines are seen as forming a viable basis for a generator system that holds considerable promise for operation that is high in reliability and low in cost.

  2. State-resolved collisional relaxation of highly vibrationally excited CsH by CO2.

    PubMed

    Mu, Baoxia; Cui, Xiuhua; Shen, Yifan; Dai, Kang

    2015-09-01

    Quenching of highly vibrationally excited CsH(X(1)Σ(+), v=15-23) by collisions with CO2 was investigated. A significant fraction of the initial population of highly vibrationally excited CsH(v=22) was relaxed to a low vibrational level (Δv=-5). The near-resonant 5-1 vibration-to-vibration (V-V) energy was efficiently exchanged. The rate constants for the rotational levels of CO2(00(0)0) [J=36-60] and CO2(00(0)1) [J=5-31] from the collisions with excited CsH were determined. The experiments revealed that the collisions resulting in CO2(00(0)0) were accompanied by substantial excitation in rotation and translation. The vibrationally excited CO2(00(0)1) state exhibited rotational and translational energy distributions near those of the initial state. The total quenching rates relative to the probed state of excited CsH were determined for both CO2 states. The corresponding data indicated that the gains in the rotational and translational energies in CO2 were sensitive to the collisional depletion of excited CsH.

  3. Doubly charged CO2 clusters formed by ionization of doped helium nanodroplets☆

    PubMed Central

    Daxner, Matthias; Denifl, Stephan; Scheier, Paul; Echt, Olof

    2014-01-01

    Helium nanodroplets are doped with carbon dioxide and ionized by electrons. Doubly charged cluster ions are, for the first time, identified based on their characteristic patterns of isotopologues. Thanks to the high mass resolution, large dynamic range, and a novel method to eliminate contributions from singly charged ions from the mass spectra, we are able to observe doubly charged cluster ions that are smaller than the ones reported in the past. The likely mechanism by which doubly charged ions are formed in doped helium droplets is discussed. PMID:25844051

  4. Interface recombination feature in metal-semiconductor junction at high photo-excitation

    NASA Astrophysics Data System (ADS)

    Konin, A.

    2014-09-01

    A theory of the photo-induced electromotive force in a p-type semiconductor accounting for the energy band bending and interface recombination dependence on excitation level is developed. It is shown that at high photo-excitation the effective interface recombination velocity in the metal-semiconductor junction is negligible compared with the volume one, when the surface potential is less than its critical value. The photo-induced electromotive force value is maximal at this condition.

  5. Advances in high-resolution RIXS for the study of excitation spectra under high pressure

    NASA Astrophysics Data System (ADS)

    Kim, Jungho

    2016-07-01

    Hard X-ray resonant inelastic X-ray scattering (RIXS) is a promising X-ray spectroscopic tool for measuring low-energy excitation spectra from complex materials under high pressure. In the past, these measurements have been stymied by technical difficulties inherent in measuring a tiny sample, held at high pressure, inside a diamond anvil cell. Now, due to substantial advances in X-ray instrumentation, high-resolution (? meV) RIXS spectrometers at third-generation synchrotron radiation sources have started to successfully address these samples in their extreme environment. However, compared to elastic X-ray scattering and X-ray emission spectroscopy, RIXS is a very photon hungry technique and high-resolution RIXS for samples under high pressure is in its infancy. In this review, the fundamentals of the high-resolution RIXS and associated instrumentation are presented, as well as technical details of diamond anvil cells, sample preparation, and the measurement geometry. Experimental data from measurements of 3d- and 5d-transition metal oxides are shown and future improvements of the RIXS technique in the context of high pressure are discussed.

  6. A highly optimized code for calculating atomic data at neutron star magnetic field strengths using a doubly self-consistent Hartree-Fock-Roothaan method

    NASA Astrophysics Data System (ADS)

    Schimeczek, C.; Engel, D.; Wunner, G.

    2012-07-01

    Our previously published code for calculating energies and bound-bound transitions of medium-Z elements at neutron star magnetic field strengths [D. Engel, M. Klews, G. Wunner, Comput. Phys. Comm. 180 (2009) 302-311] was based on the adiabatic approximation. It assumes a complete decoupling of the (fast) gyration of the electrons under the action of the magnetic field and the (slow) bound motion along the field under the action of the Coulomb forces. For the single-particle orbitals this implied that each is a product of a Landau state and an (unknown) longitudinal wave function whose B-spline coefficients were determined self-consistently by solving the Hartree-Fock equations for the many-electron problem on a finite-element grid. In the present code we go beyond the adiabatic approximation, by allowing the transverse part of each orbital to be a superposition of Landau states, while assuming that the longitudinal part can be approximated by the same wave function in each Landau level. Inserting this ansatz into the energy variational principle leads to a system of coupled equations in which the B-spline coefficients depend on the weights of the individual Landau states, and vice versa, and which therefore has to be solved in a doubly self-consistent manner. The extended ansatz takes into account the back-reaction of the Coulomb motion of the electrons along the field direction on their motion in the plane perpendicular to the field, an effect which cannot be captured by the adiabatic approximation. The new code allows for the inclusion of up to 8 Landau levels. This reduces the relative error of energy values as compared to the adiabatic approximation results by typically a factor of three (1/3 of the original error), and yields accurate results also in regions of lower neutron star magnetic field strengths where the adiabatic approximation fails. Further improvements in the code are a more sophisticated choice of the initial wave functions, which takes into

  7. A highly optimized code for calculating atomic data at neutron star magnetic field strengths using a doubly self-consistent Hartree-Fock-Roothaan method

    NASA Astrophysics Data System (ADS)

    Schimeczek, C.; Engel, D.; Wunner, G.

    2014-05-01

    Our previously published code for calculating energies and bound-bound transitions of medium-Z elements at neutron star magnetic field strengths [D. Engel, M. Klews, G. Wunner, Comp. Phys. Comm. 180, 3-2-311 (2009)] was based on the adiabatic approximation. It assumes a complete decoupling of the (fast) gyration of the electrons under the action of the magnetic field and the (slow) bound motion along the field under the action of the Coulomb forces. For the single-particle orbitals this implied that each is a product of a Landau state and an (unknown) longitudinal wave function whose B-spline coefficients were determined self-consistently by solving the Hartree-Fock equations for the many-electron problem on a finite-element grid. In the present code we go beyond the adiabatic approximation, by allowing the transverse part of each orbital to be a superposition of Landau states, while assuming that the longitudinal part can be approximated by the same wave function in each Landau level. Inserting this ansatz into the energy variational principle leads to a system of coupled equations in which the B-spline coefficients depend on the weights of the individual Landau states, and vice versa, and which therefore has to be solved in a doubly self-consistent manner. The extended ansatz takes into account the back-reaction of the Coulomb motion of the electrons along the field direction on their motion in the plane perpendicular to the field, an effect which cannot be captured by the adiabatic approximation. The new code allows for the inclusion of up to 8 Landau levels. This reduces the relative error of energy values as compared to the adiabatic approximation results by typically a factor of three (1/3 of the original error) and yields accurate results also in regions of lower neutron star magnetic field strengths where the adiabatic approximation fails. Further improvements in the code are a more sophisticated choice of the initial wave functions, which takes into

  8. Study of ultra-high gradient wakefield excitation by intense ultrashort laser pulses in plasma

    NASA Astrophysics Data System (ADS)

    Kotaki, Hideyuki; Kando, Masaki; Oketa, Takatsugu; Masuda, Shinichi; Koga, James K.; Kondo, Shuji; Kanazawa, Shuhei; Yokoyama, Takashi; Matoba, Toru; Nakajima, Kazuhisa

    2002-10-01

    We investigate a laser wakefield excited by intense laser pulses, and the possibility of generating an intense bright electron source by an intense laser pulse. The coherent wakefield excited by 2 TW, 50 fs laser pulses in a gas-jet plasma around 1018 cm-3 is measured with a time-resolved frequency domain interferometer (FDI). The results show an accelerating wakefield excitation of 20 GeV/m with good coherency. This is the first time-resolved measurement of laser wakefield excitation in a gas-jet plasma. The experimental results agree with the simulation results and linear theory. The pump-probe interferometer system of FDI will be modified to the optical injection system as a relativistic electron beam injector. In 1D particle in cell simulation we obtain results of high quality intense electron beam generation.

  9. A statistical approach to describe highly excited heavy and superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Chen, Peng-Hui; Feng, Zhao-Qing; Li, Jun-Qing; Zhang, Hong-Fei

    2016-09-01

    A statistical approach based on the Weisskopf evaporation theory has been developed to describe the de-excitation process of highly excited heavy and superheavy nuclei, in particular for the proton-rich nuclei. The excited nucleus is cooled by evaporating γ-rays, light particles (neutrons, protons, α etc) in competition with binary fission, in which the structure effects (shell correction, fission barrier, particle separation energy) contribute to the processes. The formation of residual nuclei is evaluated via sequential emission of possible particles above the separation energies. The available data of fusion-evaporation excitation functions in the 28Si+198Pt reaction can be reproduced nicely within the approach. Supported by Major State Basic Research Development Program in China (2015CB856903), National Natural Science Foundation of China Projects (11175218, U1332207, 11475050, 11175074), and Youth Innovation Promotion Association of Chinese Academy of Sciences

  10. Spectroscopy of doubly charmed baryons from lattice QCD

    SciTech Connect

    Padmanath, M.; Edwards, Robert G.; Mathur, Nilmani; Peardon, Michael

    2015-05-06

    This study presents the ground and excited state spectra of doubly charmed baryons from lattice QCD with dynamical quark fields. Calculations are performed on anisotropic lattices of size 16³ × 128, with inverse spacing in temporal direction at⁻¹=5.67(4) GeV and with a pion mass of about 390 MeV. A large set of baryonic operators that respect the symmetries of the lattice yet which retain a memory of their continuum analogues are used. These operators transform as irreducible representations of SU(3)F symmetry for flavor, SU(4) symmetry for Dirac spins of quarks and O(3) for spatial symmetry. The distillation method is utilized to generate baryon correlation functions which are analyzed using the variational fitting method to extract excited states. The lattice spectra obtained have baryonic states with well-defined total spins up to 7/2 and the pattern of low-lying states does not support the diquark picture for doubly charmed baryons. On the contrary the calculated spectra are remarkably similar to the expectations from models with an SU(6)×O(3) symmetry. Various spin-dependent energy splittings between the extracted states are also evaluated.

  11. Low excitatory innervation balances high intrinsic excitability of immature dentate neurons

    DOE PAGESBeta

    Dieni, Cristina V.; Panichi, Roberto; Aimone, James B.; Kuo, Chay T.; Wadiche, Jacques I.; Overstreet-Wadiche, Linda

    2016-04-20

    Persistent neurogenesis in the dentate gyrus produces immature neurons with high intrinsic excitability and low levels of inhibition that are predicted to be more broadly responsive to afferent activity than mature neurons. Mounting evidence suggests that these immature neurons are necessary for generating distinct neural representations of similar contexts, but it is unclear how broadly responsive neurons help distinguish between similar patterns of afferent activity. Here we show that stimulation of the entorhinal cortex in mouse brain slices paradoxically generates spiking of mature neurons in the absence of immature neuron spiking. Immature neurons with high intrinsic excitability fail to spikemore » due to insufficient excitatory drive that results from low innervation rather than silent synapses or low release probability. Here, our results suggest that low synaptic connectivity prevents immature neurons from responding broadly to cortical activity, potentially enabling excitable immature neurons to contribute to sparse and orthogonal dentate representations.« less

  12. Low excitatory innervation balances high intrinsic excitability of immature dentate neurons

    PubMed Central

    Dieni, Cristina V.; Panichi, Roberto; Aimone, James B.; Kuo, Chay T.; Wadiche, Jacques I.; Overstreet-Wadiche, Linda

    2016-01-01

    Persistent neurogenesis in the dentate gyrus produces immature neurons with high intrinsic excitability and low levels of inhibition that are predicted to be more broadly responsive to afferent activity than mature neurons. Mounting evidence suggests that these immature neurons are necessary for generating distinct neural representations of similar contexts, but it is unclear how broadly responsive neurons help distinguish between similar patterns of afferent activity. Here we show that stimulation of the entorhinal cortex in mouse brain slices paradoxically generates spiking of mature neurons in the absence of immature neuron spiking. Immature neurons with high intrinsic excitability fail to spike due to insufficient excitatory drive that results from low innervation rather than silent synapses or low release probability. Our results suggest that low synaptic connectivity prevents immature neurons from responding broadly to cortical activity, potentially enabling excitable immature neurons to contribute to sparse and orthogonal dentate representations. PMID:27095423

  13. International Ultraviolet Explorer satellite observations of seven high-excitation planetary nebulae.

    PubMed

    Aller, L H; Keyes, C D

    1980-03-01

    Observations of seven high-excitation planetary nebulae secured with the International Ultraviolet Explorer (IUE) satellite were combined with extensive ground-based data to obtain electron densities, gas kinetic temperatures, and ionic concentrations. We then employed a network of theoretical model nebulae to estimate the factors by which observed ionic concentrations must be multiplied to obtain elemental abundances. Comparison with a large sample of nebulae for which extensive ground-based observations have been obtained shows nitrogen to be markedly enhanced in some of these objects. Possibly most, if not all, high-excitation nebulae evolve from stars that have higher masses than progenitors of nebulae of low-to-moderate excitation. PMID:16592781

  14. Excited states of the high-frequency vibrational modes and kinetics of ultrafast photoinduced electron transfer

    NASA Astrophysics Data System (ADS)

    Barykov, V. Yu.; Ivanov, A. I.

    2016-02-01

    The effect of the carrier frequency of the exciting laser pulse on the kinetics of intramolecular photoinduced charge transfer in the multi-channel stochastic model is studied. It is shown that the population of different states of high-frequency intramolecular modes upon varying the frequency of the excitation pulse can considerably alter the rate constant of ultrafast charge transfer. It is found that a negative vibrational spectral effect is expected in the vicinity of a barrier-free area (the rate constant of photoinduced charge transfer decreases along with the carrier frequency of the excitation pulse), while a positive effect is predicted in areas of high and low exergonicity (an inverse dependence). It is concluded that the value of the spectral effect falls along with the time of vibrational relaxation. For ultrafast photo-induced charge transfer, however, it remains considerable up to relaxation times of 100 fs.

  15. Low excitatory innervation balances high intrinsic excitability of immature dentate neurons.

    PubMed

    Dieni, Cristina V; Panichi, Roberto; Aimone, James B; Kuo, Chay T; Wadiche, Jacques I; Overstreet-Wadiche, Linda

    2016-04-20

    Persistent neurogenesis in the dentate gyrus produces immature neurons with high intrinsic excitability and low levels of inhibition that are predicted to be more broadly responsive to afferent activity than mature neurons. Mounting evidence suggests that these immature neurons are necessary for generating distinct neural representations of similar contexts, but it is unclear how broadly responsive neurons help distinguish between similar patterns of afferent activity. Here we show that stimulation of the entorhinal cortex in mouse brain slices paradoxically generates spiking of mature neurons in the absence of immature neuron spiking. Immature neurons with high intrinsic excitability fail to spike due to insufficient excitatory drive that results from low innervation rather than silent synapses or low release probability. Our results suggest that low synaptic connectivity prevents immature neurons from responding broadly to cortical activity, potentially enabling excitable immature neurons to contribute to sparse and orthogonal dentate representations.

  16. Low excitatory innervation balances high intrinsic excitability of immature dentate neurons.

    PubMed

    Dieni, Cristina V; Panichi, Roberto; Aimone, James B; Kuo, Chay T; Wadiche, Jacques I; Overstreet-Wadiche, Linda

    2016-01-01

    Persistent neurogenesis in the dentate gyrus produces immature neurons with high intrinsic excitability and low levels of inhibition that are predicted to be more broadly responsive to afferent activity than mature neurons. Mounting evidence suggests that these immature neurons are necessary for generating distinct neural representations of similar contexts, but it is unclear how broadly responsive neurons help distinguish between similar patterns of afferent activity. Here we show that stimulation of the entorhinal cortex in mouse brain slices paradoxically generates spiking of mature neurons in the absence of immature neuron spiking. Immature neurons with high intrinsic excitability fail to spike due to insufficient excitatory drive that results from low innervation rather than silent synapses or low release probability. Our results suggest that low synaptic connectivity prevents immature neurons from responding broadly to cortical activity, potentially enabling excitable immature neurons to contribute to sparse and orthogonal dentate representations. PMID:27095423

  17. Mapping Ultrafast Dynamics of Highly Excited H2by Attosecond VUV-Radiation

    NASA Astrophysics Data System (ADS)

    Weber, Thorsten; Sturm, Felix; Wright, Travis; Ray, Dipanwita; Shivaram, Niranjan; Slaughter, Daniel; Bocharova, Irina; Ranitovic, Predrag; Belkacem, Ali

    2016-05-01

    We show how attosecond vacuum ultraviolet (VUV) and femtosecond infrared (IR) radiation can be used to excite and map dynamics of a highly excited neutral hydrogen molecule. By using time-delayed, strong laser pulses and ion imaging, we map the dynamics of highly-excited, bound states of hydrogen molecules. Due to the large stretching amplitude of the B electronic state, excited by the 9th harmonic of the fundamental laser frequency, the effective ionization potential of the hydrogen molecular ion changes substantially as the nuclear wave packet (NWP) vibrates in the bound, B potential energy curve. Therefore, the probability of ionizing the neutrally-excited hydrogen molecule by the IR probe pulse changes as the NWP evolves in the B potential. We probe this dynamics by ionizing the vibrating molecule by means of time-delayed IR radiation, and identify the dissociation channels with 3D-momentum ion imaging. Supported by DOE under Contract No. DE-AC02-05CH11231.

  18. High excitation power photoluminescence studies of ultra-low density GaAs quantum dots

    SciTech Connect

    Sonnenberg, D.; Graf, A.; Paulava, V.; Heyn, Ch.; Hansen, W.

    2013-12-04

    We fabricate GaAs epitaxial quantum dots (QDs) by filling of self-organized nanoholes in AlGaAs. The QDs are fabricated under optimized process conditions and have ultra-low density in the 10{sup 6} cm{sup −2} regime. At low excitation power the optical emission of single QDs exhibit sharp excitonic lines, which are attributed to the recombination of excitonic and biexcitonic states. High excitation power measurements reveal surprisingly broad emission lines from at least six QD shell states.

  19. Validity of Eucken formula and Stokes’ viscosity relation in high-temperature electronically excited gases

    SciTech Connect

    Istomin, V. A.; Kustova, E. V.; Mekhonoshina, M. A.

    2014-12-09

    In the present work we evaluate the accuracy of the Eucken formula and Stokes’ viscosity relation in high temperature non-equilibrium air species with electronic excitation. The thermal conductivity coefficient calculated using the exact kinetic theory methods is compared with that obtained applying approximate formulas in the temperature range 200–20000 K. A modification of the Eucken formula providing a good agreement with exact calculations is proposed. It is shown that the Stokes viscosity relation is not valid in electronically excited monoatomic gases at temperatures higher than 2000 K.

  20. Ultraviolet high-excitation Fe II fluorescence lines excited by O VI, C IV, and H I resonance emission as seen in IUE spectra

    NASA Technical Reports Server (NTRS)

    Feibelman, Walter A.; Bruhweiler, Frederick C.; Johansson, Sveneric

    1991-01-01

    Archival high-dispersion spectra from the IUE are used in a search for Bowen emission lines of Fe II excited by the stronger transition of the O VI resonance doublet. The possibility of using these Fe II emission lines as a diagnostic of the strength of the far-ultraviolet emission of O VI at 1032 A is explored. It is found that the Fe II emission lines are quite common and strong in symbiotic stars, particularly those of the type known as 'symbiotic novae', as well as in normal novae. The lines are observed in central stars of some planetary nebulae of the O VI sequence besides a few central stars of type WR. High density, high excitation, and high temperature are suggested to be requirements for the excitation of the Fe II fluorescence lines. It is pointed out that while these lines were observed in PG 1159-035 and K1-16, they were not observed in AGNs.

  1. Collision dynamics of methyl radicals and highly vibrationally excited molecules using crossed molecular beams

    SciTech Connect

    Chu, P.M.Y.

    1991-10-01

    The vibrational to translational (V{yields}T) energy transfer in collisions between large highly vibrationally excited polyatomics and rare gases was investigated by time-of-flight techniques. Two different methods, UV excitation followed by intemal conversion and infrared multiphoton excitation (IRMPE), were used to form vibrationally excited molecular beams of hexafluorobenzene and sulfur hexafluoride, respectively. The product translational energy was found to be independent of the vibrational excitation. These results indicate that the probability distribution function for V{yields}T energy transfer is peaked at zero. The collisional relaxation of large polyatomic molecules with rare gases most likely occurs through a rotationally mediated process. Photodissociation of nitrobenzene in a molecular beam was studied at 266 nm. Two primary dissociation channels were identified including simple bond rupture to produce nitrogen dioxide and phenyl radical and isomerization to form nitric oxide and phenoxy radical. The time-of-flight spectra indicate that simple bond rupture and isomerization occurs via two different mechanisms. Secondary dissociation of the phenoxy radicals to carbon monoxide and cyclopentadienyl radicals was observed as well as secondary photodissociation of phenyl radical to give H atom and benzyne. A supersonic methyl radical beam source is developed. The beam source configuration and conditions were optimized for CH{sub 3} production from the thermal decomposition of azomethane. Elastic scattering of methyl radical and neon was used to differentiate between the methyl radicals and the residual azomethane in the molecular beam.

  2. Low energy nuclear spin excitations in Ho metal investigated by high resolution neutron spectroscopy.

    PubMed

    Chatterji, Tapan; Jalarvo, Niina

    2013-04-17

    We have investigated the low energy excitations in metallic Ho by high resolution neutron spectroscopy. We found at T = 3 K clear inelastic peaks in the energy loss and energy gain sides, along with the central elastic peak. The energy of this low energy excitation, which is 26.59 ± 0.02 μeV at T = 3 K, decreased continuously and became zero at TN ≈ 130 K. By fitting the data in the temperature range 100-127.5 K with a power law we obtained the power-law exponent β = 0.37 ± 0.02, which agrees with the expected value β = 0.367 for a three-dimensional Heisenberg model. Thus the energy of the low energy excitations can be associated with the order parameter.

  3. Interaction of highly vibrationally excited molecules with clean metal surfaces. Final technical report

    SciTech Connect

    Wodtke, A.M.; Auerbach, D.J.

    1998-11-01

    The authors present results from a grant funded under the Department of Energy Office of Basic Energy Sciences. A collaboration between Prof. Alec Wodtke of the Department of Chemistry at UCSB and Daniel J. Auerbach of IBM Almaden Research Labs has allowed new experiments on the dynamics of surface chemical reactivity to be successfully executed. High quality data has been generated which provides an excellent test of theoretical models of surface reactivity, a topic of importance to catalysis. The authors have obtained the first experimental measurements on the influence of reactant velocity on the steric effect in a chemical reaction: the dissociative adsorption of hydrogen on copper. They have also designed and built a molecular beam scattering apparatus for the study of highly vibrationally excited molecules and their interactions with clean and oxidized metal surfaces. With this apparatus they have observed the vibrational energy exchange of highly vibrationally excited NO with an oxidized copper surface. Multi-quantum vibrational relaxation was found ({Delta}v = 1-5). Such remarkably strong and efficient vibrational energy transfer represents a qualitatively new phenomenon and is representative of the exciting new behavior that they had hoped might be observable in this project. Evidence of chemical reactivity of vibrationally excited NO on a clean copper surface was also found.

  4. Application of Excitation from Multiple Locations on a Simplified High-Lift System

    NASA Technical Reports Server (NTRS)

    Melton, LaTunia Pack; Yao, Chung-Sheng; Seifert, Avi

    2004-01-01

    A series of active flow control experiments were recently conducted on a simplified high-lift system. The purpose of the experiments was to explore the prospects of eliminating all but simply hinged leading and trailing edge flaps, while controlling separation on the supercritical airfoil using multiple periodic excitation slots. Excitation was provided by three. independently controlled, self-contained, piezoelectric actuators. Low frequency excitation was generated through amplitude modulation of the high frequency carrier wave, the actuators' resonant frequencies. It was demonstrated, for the first time, that pulsed modulated signal from two neighboring slots interact favorably to increase lift. Phase sensitivity at the low frequency was measured, even though the excitation was synthesized from the high-frequency carrier wave. The measurements were performed at low Reynolds numbers and included mean and unsteady surface pressures, surface hot-films, wake pressures and particle image velocimetry. A modest (6%) increase in maximum lift (compared to the optimal baseline) was obtained due t o the activation of two of the three actuators.

  5. Electronically Excited States in Poly(p-phenylenevinylene): Vertical Excitations and Torsional Potentials from High-Level Ab Initio Calculations

    PubMed Central

    2013-01-01

    Ab initio second-order algebraic diagrammatic construction (ADC(2)) calculations using the resolution of the identity (RI) method have been performed on poly-(p-phenylenevinylene) (PPV) oligomers with chain lengths up to eight phenyl rings. Vertical excitation energies for the four lowest π–π* excitations and geometry relaxation effects for the lowest excited state (S1) are reported. Extrapolation to infinite chain length shows good agreement with analogous data derived from experiment. Analysis of the bond length alternation (BLA) based on the optimized S1 geometry provides conclusive evidence for the localization of the defect in the center of the oligomer chain. Torsional potentials have been computed for the four excited states investigated and the transition densities divided into fragment contributions have been used to identify excitonic interactions. The present investigation provides benchmark results, which can be used (i) as reference for lower level methods and (ii) give the possibility to parametrize an effective Frenkel exciton Hamiltonian for quantum dynamical simulations of ultrafast exciton transfer dynamics in PPV type systems. PMID:23427902

  6. A Spectral Finite Element Approach to Modeling Soft Solids Excited with High-Frequency Harmonic Loads

    PubMed Central

    Brigham, John C.; Aquino, Wilkins; Aguilo, Miguel A.; Diamessis, Peter J.

    2010-01-01

    An approach for efficient and accurate finite element analysis of harmonically excited soft solids using high-order spectral finite elements is presented and evaluated. The Helmholtz-type equations used to model such systems suffer from additional numerical error known as pollution when excitation frequency becomes high relative to stiffness (i.e. high wave number), which is the case, for example, for soft tissues subject to ultrasound excitations. The use of high-order polynomial elements allows for a reduction in this pollution error, but requires additional consideration to counteract Runge's phenomenon and/or poor linear system conditioning, which has led to the use of spectral element approaches. This work examines in detail the computational benefits and practical applicability of high-order spectral elements for such problems. The spectral elements examined are tensor product elements (i.e. quad or brick elements) of high-order Lagrangian polynomials with non-uniformly distributed Gauss-Lobatto-Legendre nodal points. A shear plane wave example is presented to show the dependence of the accuracy and computational expense of high-order elements on wave number. Then, a convergence study for a viscoelastic acoustic-structure interaction finite element model of an actual ultrasound driven vibroacoustic experiment is shown. The number of degrees of freedom required for a given accuracy level was found to consistently decrease with increasing element order. However, the computationally optimal element order was found to strongly depend on the wave number. PMID:21461402

  7. Highly Selective Dissociation of a Peptide Bond Following Excitation of Core Electrons.

    PubMed

    Lin, Yi-Shiue; Tsai, Cheng-Cheng; Lin, Huei-Ru; Hsieh, Tsung-Lin; Chen, Jien-Lian; Hu, Wei-Ping; Ni, Chi-Kung; Liu, Chen-Lin

    2015-06-18

    The controlled breaking of a specific chemical bond with photons in complex molecules remains a major challenge in chemistry. In principle, using the K-edge absorption of a particular atomic element, one might excite selectively a specific atomic entity in a molecule. We report here highly selective dissociation of the peptide bonds in N-methylformamide and N-methylacetamide on tuning the X-ray wavelength to the K-edge absorption of the atoms connected to (or near) the peptide bond. The high selectivity (56-71%) of this cleavage arises from the large energy shift of X-ray absorption, a large overlap of the 1s orbital and the valence π* orbital that is highly localized on a peptide bond with antibonding character, and the relatively low bond energy of the peptide bonds. These characteristics indicate that the high selectivity on bond dissociation following core excitation could be a general feature for molecules containing peptide bonds.

  8. Nonlinear vibrations of functionally graded doubly curved shallow shells

    NASA Astrophysics Data System (ADS)

    Alijani, F.; Amabili, M.; Karagiozis, K.; Bakhtiari-Nejad, F.

    2011-03-01

    Nonlinear forced vibrations of FGM doubly curved shallow shells with a rectangular base are investigated. Donnell's nonlinear shallow-shell theory is used and the shell is assumed to be simply supported with movable edges. The equations of motion are reduced using the Galerkin method to a system of infinite nonlinear ordinary differential equations with quadratic and cubic nonlinearities. Using the multiple scales method, primary and subharmonic resonance responses of FGM shells are fully discussed and the effect of volume fraction exponent on the internal resonance conditions, softening/hardening behavior and bifurcations of the shallow shell when the excitation frequency is (i) near the fundamental frequency and (ii) near two times the fundamental frequency is shown. Moreover, using a code based on arclength continuation method, a bifurcation analysis is carried out for a special case with two-to-one internal resonance between the first and second doubly symmetric modes with respect to the panel's center ( ω13≈2 ω11). Bifurcation diagrams and Poincaré maps are obtained through direct time integration of the equations of motion and chaotic regions are shown by calculating Lyapunov exponents and Lyapunov dimension.

  9. Current status of free radicals and electronically excited metastable species as high energy propellants

    NASA Technical Reports Server (NTRS)

    Rosen, G.

    1973-01-01

    A survey is presented of free radicals and electronically excited metastable species as high energy propellants for rocket engines. Nascent or atomic forms of diatomic gases are considered free radicals as well as the highly reactive diatomic triatomic molecules that posess unpaired electrons. Manufacturing and storage problems are described, and a review of current experimental work related to the manufacture of atomic hydrogen propellants is presented.

  10. Isospin Splittings of Doubly Heavy Baryons

    SciTech Connect

    Brodsky, Stanley J.; Guo, Feng-Kun; Hanhart, Christoph; Meissner, Ulf-G.; /Julich, Forschungszentrum /JCHP, Julich /IAS, Julich /Bonn U., HISKP /Bonn U.

    2011-08-18

    The SELEX Collaboration has reported a very large isospin splitting of doubly charmed baryons. We show that this effect would imply that the doubly charmed baryons are very compact. One intriguing possibility is that such baryons have a linear geometry Q-q-Q where the light quark q oscillates between the two heavy quarks Q, analogous to a linear molecule such as carbon dioxide. However, using conventional arguments, the size of a heavy-light hadron is expected to be around 0.5 fm, much larger than the size needed to explain the observed large isospin splitting. Assuming the distance between two heavy quarks is much smaller than that between the light quark and a heavy one, the doubly heavy baryons are related to the heavy mesons via heavy quark-diquark symmetry. Based on this symmetry, we predict the isospin splittings for doubly heavy baryons including {Xi}{sub cc}, {Xi}{sub bb} and {Xi}{sub bc}. The prediction for the {Xi}{sub cc} is much smaller than the SELEX value. On the other hand, the {Xi}{sub bb} baryons are predicted to have an isospin splitting as large as (6.3 {+-} 1.7) MeV. An experimental study of doubly bottomed baryons is therefore very important to better understand the structure of baryons with heavy quarks.

  11. Boosting brain excitability by transcranial high frequency stimulation in the ripple range

    PubMed Central

    Moliadze, Vera; Antal, Andrea; Paulus, Walter

    2010-01-01

    Alleviating the symptoms of neurological diseases by increasing cortical excitability through transcranial stimulation is an ongoing scientific challenge. Here, we tackle this issue by interfering with high frequency oscillations (80–250 Hz) via external application of transcranial alternating current stimulation (tACS) over the human motor cortex (M1). Twenty-one subjects participated in three different experimental studies and they received on separate days tACS at three frequencies (80 Hz, 140 Hz and 250 Hz) and sham stimulation in a randomized order. tACS with 140 Hz frequency increased M1 excitability as measured by transcranial magnetic stimulation-generated motor evoked potentials (MEPs) during and for up to 1 h after stimulation. Control experiments with sham and 80 Hz stimulation were without any effect, and 250 Hz stimulation was less efficient with a delayed excitability induction and reduced duration. After-effects elicited by 140 Hz stimulation were robust against inversion of test MEP amplitudes seen normally under activation. Stimulation at 140 Hz reduced short interval intracortical inhibition, but left intracortical facilitation, long interval cortical inhibition and cortical silent period unchanged. Implicit motor learning was not facilitated by 140 Hz stimulation. High frequency stimulation in the ripple range is a new promising non-invasive brain stimulation protocol to increase human cortical excitability during and after the end of stimulation. PMID:20962008

  12. A proposal for fs-electron microscopy experiments on high-energy excitations in solids.

    PubMed

    Piazza, L; Musumeci, P; Luiten, O J; Carbone, Fabrizio

    2014-08-01

    Recent advances in ultrafast technology enable both the study and the control of materials properties thanks to the ability to record high temporal resolution movies of their transformations, or the ability to generate new states of matter by selecting ad hoc an excitation to drive the system out of equilibrium. The holy grail of this type of experiments is to combine a high tuneability of the excitation with a wide observation window. For example, this is achieved in multidimensional optical spectroscopy where the response to several excitation energies is monitored in a broad energy range by a large bandwidth optical pulse. In this article, the possibility to combine the chemical sensitivity of intense tuneable X-rays pulses from a free electron laser, with the wide range of observables available in an ultrafast transmission electron microscope is discussed. The requirements for such experiments are quantified via estimates based on state of the art experiments and simulations, and it is proposed that ultrafast electron imaging, diffraction and spectroscopy experiments can be performed in combination with a chemically selective X-ray excitation of materials. PMID:24631423

  13. Boosting brain excitability by transcranial high frequency stimulation in the ripple range.

    PubMed

    Moliadze, Vera; Antal, Andrea; Paulus, Walter

    2010-12-15

    Alleviating the symptoms of neurological diseases by increasing cortical excitability through transcranial stimulation is an ongoing scientific challenge. Here, we tackle this issue by interfering with high frequency oscillations (80–250 Hz) via external application of transcranial alternating current stimulation (tACS) over the human motor cortex (M1). Twenty-one subjects participated in three different experimental studies and they received on separate days tACS at three frequencies (80 Hz, 140 Hz and 250 Hz) and sham stimulation in a randomized order. tACS with 140 Hz frequency increased M1 excitability as measured by transcranial magnetic stimulation-generated motor evoked potentials (MEPs) during and for up to 1 h after stimulation. Control experiments with sham and 80 Hz stimulation were without any effect, and 250 Hz stimulation was less efficient with a delayed excitability induction and reduced duration. After-effects elicited by 140 Hz stimulation were robust against inversion of test MEP amplitudes seen normally under activation. Stimulation at 140 Hz reduced short interval intracortical inhibition, but left intracortical facilitation, long interval cortical inhibition and cortical silent period unchanged. Implicit motor learning was not facilitated by 140 Hz stimulation. High frequency stimulation in the ripple range is a new promising non-invasive brain stimulation protocol to increase human cortical excitability during and after the end of stimulation.

  14. Communication: excitation band modulation with high-order photonic band gap in PMMA:Eu(TTA)3(TPPO)2 opals.

    PubMed

    Xu, Wen; Bai, Xue; Zhu, Yongsheng; Liu, Tong; Xu, Sai; Dong, Biao; Song, Hongwei

    2013-05-14

    Changes in the excitation spectra of luminescent species inserted in photorefractive crystals as a function of changes in the high-order photonic band gap (PBG) have not been previously observed. In this communication, we present our results monitoring the excitation band of Eu(TTA)3(TPPO)2 inserted in the PMMA opal photonic crystals as a function of the changes in the high-order PBG of the crystals. We find shifts in the complex excitation band and changes in the integrated emission intensity that correlates with shifts in the high-order PBG through coupling to the excitation transition. PMID:23676019

  15. Communication: Excitation band modulation with high-order photonic band gap in PMMA:Eu(TTA)3(TPPO)2 opals

    NASA Astrophysics Data System (ADS)

    Xu, Wen; Bai, Xue; Zhu, Yongsheng; Liu, Tong; Xu, Sai; Dong, Biao; Song, Hongwei

    2013-05-01

    Changes in the excitation spectra of luminescent species inserted in photorefractive crystals as a function of changes in the high-order photonic band gap (PBG) have not been previously observed. In this communication, we present our results monitoring the excitation band of Eu(TTA)3(TPPO)2 inserted in the PMMA opal photonic crystals as a function of the changes in the high-order PBG of the crystals. We find shifts in the complex excitation band and changes in the integrated emission intensity that correlates with shifts in the high-order PBG through coupling to the excitation transition.

  16. Communication: excitation band modulation with high-order photonic band gap in PMMA:Eu(TTA)3(TPPO)2 opals.

    PubMed

    Xu, Wen; Bai, Xue; Zhu, Yongsheng; Liu, Tong; Xu, Sai; Dong, Biao; Song, Hongwei

    2013-05-14

    Changes in the excitation spectra of luminescent species inserted in photorefractive crystals as a function of changes in the high-order photonic band gap (PBG) have not been previously observed. In this communication, we present our results monitoring the excitation band of Eu(TTA)3(TPPO)2 inserted in the PMMA opal photonic crystals as a function of the changes in the high-order PBG of the crystals. We find shifts in the complex excitation band and changes in the integrated emission intensity that correlates with shifts in the high-order PBG through coupling to the excitation transition.

  17. Highly efficient terahertz wave modulators by photo-excitation of organics/silicon bilayers

    SciTech Connect

    Yoo, Hyung Keun; Kang, Chul; Hwang, In-Wook; Yoon, Youngwoon; Lee, Kiejin; Kee, Chul-Sik; Lee, Joong Wook

    2014-07-07

    Using hybrid bilayer systems comprising a molecular organic semiconductor and silicon, we achieve optically controllable active terahertz (THz) modulators that exhibit extremely high modulation efficiencies. A modulation efficiency of 98% is achieved from thermally annealed C{sub 60}/silicon bilayers, due to the rapid photo-induced electron transfer from the excited states of the silicon onto the C{sub 60} layer. Furthermore, we demonstrate the broadband modulation of THz waves. The cut-off condition of the system that is determined by the formation of efficient charge separation by the photo-excitation is highly variable, changing the system from insulating to metallic. The phenomenon enables an extremely high modulation bandwidth and rates of electromagnetic waves of interest. The realization of near-perfect modulation efficiency in THz frequencies opens up the possibilities of utilizing active modulators for THz spectroscopy and communications.

  18. High-frequency excitation of earth rotation parameters by the atmosphere

    NASA Astrophysics Data System (ADS)

    Xie, Bo-Quan; Zheng, Da-Wei

    1996-02-01

    Using the ERP series from space geodetic measurement in the period 1983-1992 and the AAM series from global meteorological data we analyzed the high-frequency (timescales below one month) excitation of LOD and polar drift by the atmosphere. We found: 1) The atmosphere has an effect on the estimated value of the high-frequency tides of the LOD component, whereas the variation of the tidal distortion parameter k/c is caused by non-atmospheric factors. 2) The atmosphere can account for most part of the non-tidal variation of LOD below 30 d. 3) The high-frequency variations below 30 d of the polar drift are mainly excited by the atmosphere. The atmosphere can contribute as much as 70% to the 27 d-variation in the x-component.

  19. Double resonance spectroscopy of several highly excited rovibronic states of H2

    NASA Astrophysics Data System (ADS)

    Ekey, R. C., Jr.; McCormack, E. F.

    2005-04-01

    The energies of several highly excited levels of the B1Σ+u, B'1Σ+u and C 1Πu states of molecular hydrogen, located several hundred wave numbers below the second dissociation limit, have been measured using two-colour, resonantly enhanced multi-photon ionization. The states were probed by excitation from the double-well E, F 1Σ+u state, populated by two-photon excitation from the ground state. Ion production was detected as a function of wavelength using a time-of-flight mass spectrometer. Non-adiabatic couplings extensively mix the configurations of the B 1Σ+u, B'1Σ+u and C 1Πu states leading to perturbations that are predicted to vary considerably as a function of rotational and vibrational excitation. Term energies are compared to previous measurements and to ab initio theoretical calculations which include non-adiabatic effects. Several observed discrepancies with the calculations and previously reported energies are discussed. Term energies for two rovibronic levels are reported for the first time.

  20. Highly correlated systems. Excitation energies of first row transition metals Sc-Cu

    NASA Astrophysics Data System (ADS)

    Raghavachari, Krishnan; Trucks, Gary W.

    1989-07-01

    The low-lying dns2→dn+1s1 excitation energies of the first row transition metal atoms Sc-Cu are calculated using fourth-order M≂ller-Plesset perturbation theory (MP4) as well as quadratic configuration interaction (QCI) techniques with large spd and spdf basis sets. The MP4 method performs well for Sc-Mn but fails dramatically for Fe-Cu. In contrast, the QCI technique performs uniformly for all excitation energies with a mean deviation from experiment of only 0.14 eV after including relativistic corrections. f functions contribute 0.1-0.4 eV to the excitation energies for these systems. The highly correlated d10 state of the Ni atom is also considered in detail. The QCI technique obtains the d9s1→d10 splitting of the Ni atom with an error of only 0.13 eV. The results show that single-configuration Hartree-Fock based methods can be successful in calculating excitation energies of transition metal atoms.

  1. Nonthermal Optical Emission Spectrometry: Direct Atomization and Excitation of Cadmium for Highly Sensitive Determination.

    PubMed

    Cai, Yi; Zhang, Ya-Jie; Wu, De-Fu; Yu, Yong-Liang; Wang, Jian-Hua

    2016-04-19

    The low atomization and excitation capability of nonthermal microplasma, e.g., dielectric barrier discharge (DBD), has greatly hampered its potential applications for the determination of metals in solution. In the present work, an inspiring development is reported for direct atomization and excitation of cadmium in aqueous solution by DBD and facilitates highly sensitive determination. A DBD microplasma is generated on the nozzle of a pneumatic micronebulizer to focus the DBD energy on a confined space and atomize/excite metals in the spray. Meanwhile, an appropriate sample matrix and nebulization in helium further improves the atomization and excitation capability of DBD. With cadmium as a model, its emission is recorded by a CCD spectrometer at 228.8 nm. By using an 80 μL sample solution nebulized at 3 μL s(-1), a linear range of 5-1000 μg L(-1) along with a detection limit of 1.5 μg L(-1) is achieved, which is comparable to those obtained by commercial bulky inductively coupled plasma (ICP)-based instrumentations. PMID:27030025

  2. Doubly fed machine review: agenda. Conference report, Washington, DC

    SciTech Connect

    Not Available

    1982-09-01

    The visual aids presented at the doubly fed machine review are presented. The doubly fed machine is a generating system either for wind turbines or hydro systems. Conceptual design and trade-offs are included, as well as testing. (LEW)

  3. Properties of Doubly Heavy Baryons in the Relativistic Quark Model

    SciTech Connect

    Ebert, D.; Faustov, R.N.; Galkin, V.O.; Martynenko, A.P.

    2005-05-01

    Mass spectra and semileptonic decay rates of baryons consisting of two heavy (b or c) and one light quark are calculated in the framework of the relativistic quark model. The doubly heavy baryons are treated in the quark-diquark approximation. The ground and excited states of both the diquark and quark-diquark bound systems are considered. The quark-diquark potential is constructed. The light quark is treated completely relativistically, while the expansion in the inverse heavy-quark mass is used. The weak transition amplitudes of heavy diquarks bb and bc going, respectively, to bc and cc are explicitly expressed through the overlap integrals of the diquark wave functions in the whole accessible kinematic range. The relativistic baryon wave functions of the quark-diquark bound system are used for the calculation of the decay matrix elements, the Isgur-Wise function, and decay rates in the heavy-quark limit.

  4. Stand-Alone Front-End System for High-Frequency, High-Frame-Rate Coded Excitation Ultrasonic Imaging

    PubMed Central

    Park, Jinhyoung; Hu, Changhong; Shung, K. Kirk

    2012-01-01

    A stand-alone front-end system for high-frequency coded excitation imaging was implemented to achieve a wider dynamic range. The system included an arbitrary waveform amplifier, an arbitrary waveform generator, an analog receiver, a motor position interpreter, a motor controller and power supplies. The digitized arbitrary waveforms at a sampling rate of 150 MHz could be programmed and converted to an analog signal. The pulse was subsequently amplified to excite an ultrasound transducer, and the maximum output voltage level achieved was 120 Vpp. The bandwidth of the arbitrary waveform amplifier was from 1 to 70 MHz. The noise figure of the preamplifier was less than 7.7 dB and the bandwidth was 95 MHz. Phantoms and biological tissues were imaged at a frame rate as high as 68 frames per second (fps) to evaluate the performance of the system. During the measurement, 40-MHz lithium niobate (LiNbO3) single-element lightweight (<0.28 g) transducers were utilized. The wire target measurement showed that the −6-dB axial resolution of a chirp-coded excitation was 50 µm and lateral resolution was 120 µm. The echo signal-to-noise ratios were found to be 54 and 65 dB for the short burst and coded excitation, respectively. The contrast resolution in a sphere phantom study was estimated to be 24 dB for the chirp-coded excitation and 15 dB for the short burst modes. In an in vivo study, zebrafish and mouse hearts were imaged. Boundaries of the zebrafish heart in the image could be differentiated because of the low-noise operation of the implemented system. In mouse heart images, valves and chambers could be readily visualized with the coded excitation. PMID:23443698

  5. High gain x-ray lasers pumped by transient collisional excitation

    SciTech Connect

    Dunn, J., LLNL

    1998-06-16

    We present recent results of x-ray laser amplification of spontaneous emission in Ne-like and Ni-like transient collisional excitation schemes. The plasma formation, ionization and collisional excitation can be optimized using two laser pulses of 1 ns and 1 ps duration at table-top energies of 5 J in each beam. High gain of 35 cm{sup -1} has been measured on the 147 {Angstrom} 4d{r_arrow}4p J=0{r_arrow}1 transition of Ni-like Pd and is a direct consequence of the nonstationary population inversion produced by the high intensity picosecond pulse. We report the dependence of the x-ray laser line intensity on the laser plasma conditions and compare the experimental measurements with hydrodynamic and atomic kinetics simulations for Ne-like and Ni-like lasing.

  6. Study of M1 and E1 excitations by high-resolution proton inelastic scattering measurement at forward angles

    SciTech Connect

    Tamii, A.; Adachi, T.; Hatanaka, K.; Hashimoto, H.; Kaneda, T.; Matsubara, H.; Okamura, H.; Sakemi, Y.; Shimizu, Y.; Tameshige, Y.; Yosoi, M.; Carter, J.; Dozono, M.; Fujita, H.; Fujita, Y.; Itoh, M.; Kawabata, T.; Nakanishi, K.; Sasamoto, Y.; Neumann-Cosel, P. von

    2007-06-13

    Experimental technique for measuring proton inelastic scattering with high-resolution at 295 MeV and at forward angles including zero degrees is described. The method is useful for extracting spin part of the M1 strength via nuclear excitation as well as E1 strength via Coulomb excitation. An excitation energy resolution of 20 keV, good scattering angle resolution, and low background condition have been achieved. The experimental technique was applied for several sd and pf shell nuclei.

  7. Long-term spectroscopy of η Carinae. I. The high and low excitation phases

    NASA Astrophysics Data System (ADS)

    Damineli, A.; Stahl, O.; Kaufer, A.; Wolf, B.; Quast, G.; Lopes, D. F.

    1998-12-01

    Quantitative measurements of line parameters in the spectrum of η Carinae are presented for both the broad and narrow line components. A total of 655 spectral features were measured in the spectral range 3850 Angstroms to 11000 Angstroms, giving a comprehensive view of the behavior of atomic transitions ranging from a few to tens of electron volts. The spectrum on the phase of maximum intensity in the high excitation lines (1995) is compared with that on minimum intensity (June 1992), showing that at this phase the high excitation lines disappear but the broad components of low excitation lines strengthens. We reject a number of previous line identifications and propose several new ones, including Fe II, [Fe II], [Fe III], [N II], and the near-infrared Ca II triplet. Some lines commonly used to diagnose density, temperature, chemical composition, and reddening were found to be blended, urging a revision of the results based on previous data. The existence of double-peaked lines, suggested in previous papers, is ruled out. In the case of hydrogen lines, the apparent double-peaks are shown to be real absorption components. The velocity field in the inner 2 arcsec around the central star shows additional components previously unknown. The phases of high and low excitation in η Carinae are discussed in light of a recently proposed binary system. We suggest a temperature T ~ 16000 K for the primary star, what indicates that it is close to the beginning of the core helium-burning evolutionary stage. Based on data collected at European Southern Observatory and Laboratorio Nacional de Astrofisica. Table 1 is only 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/Abstract.html

  8. Energy shift of collective electron excitations in highly corrugated graphitic nanostructures: Experimental and theoretical investigation

    SciTech Connect

    Sedelnikova, O. V. Bulusheva, L. G.; Okotrub, A. V.; Asanov, I. P.; Yushina, I. V.

    2014-04-21

    Effect of corrugation of hexagonal carbon network on the collective electron excitations has been studied using optical absorption and X-ray photoelectron spectroscopy in conjunction with density functional theory calculations. Onion-like carbon (OLC) was taken as a material, where graphitic mantle enveloping agglomerates of multi-shell fullerenes is strongly curved. Experiments showed that positions of π and π + σ plasmon modes as well as π → π* absorption peak are substantially redshifted for OLC as compared with those of highly ordered pyrolytic graphite and thermally exfoliated graphite consisted of planar sheets. This effect was reproduced in behavior of dielectric functions of rippled graphite models calculated within the random phase approximation. We conclude that the energy of electron excitations in graphitic materials could be precisely tuned by a simple bending of hexagonal network without change of topology. Moreover, our investigation suggests that in such materials optical exciton can transfer energy to plasmon non-radiatively.

  9. Resonance Excitation of Longitudinal High Order Modes in Project X Linac

    SciTech Connect

    Khabiboulline, T.N.; Sukhanov, A.AUTHOR = Awida, M.; Gonin, I.; Lunin, A.AUTHOR = Solyak, N.; Yakovlev, V.; /Fermilab

    2012-05-01

    Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.

  10. Excited doublet and quartet states of SiP: a high level theoretical investigation

    NASA Astrophysics Data System (ADS)

    dos Santos, Levi G.; Ornellas, Fernando R.

    2003-12-01

    Doublet and quartet states of the SiP molecule dissociating into the four lowest dissociation channels are characterized theoretically at a high-level of correlation treatment (multireference single and double excitation configuration interaction). Potential energy curves give a global view of the manifold of possible electronic states. For selected states, dipole and transition moment functions, and transition probabilities and radiative lifetimes are also reported as well as an extensive set of spectroscopic constants. A new 2Π state offers another likely route for exploring transitions to excited vibrational states of both X 2Π and A 2Σ+ states. A detailed set of data for the quartet states is expected to provide valuable information for the experimental identification of these states.

  11. The dynamics of highly excited electronic systems: Applications of the electron force field

    NASA Astrophysics Data System (ADS)

    Su, Julius T.; Goddard, William A.

    2009-12-01

    Highly excited heterogeneous complex materials are essential elements of important processes, ranging from inertial confinement fusion to semiconductor device fabrication. Understanding the dynamics of these systems has been challenging because of the difficulty in extracting mechanistic information from either experiment or theory. We describe here the electron force field (eFF) approximation to quantum mechanics which provides a practical approach to simulating the dynamics of such systems. eFF includes all the normal electrostatic interactions between electrons and nuclei and the normal quantum mechanical description of kinetic energy for the electrons, but contains two severe approximations: first, the individual electrons are represented as floating Gaussian wave packets whose position and size respond instantaneously to various forces during the dynamics; and second, these wave packets are combined into a many-body wave function as a Hartree product without explicit antisymmetrization. The Pauli principle is accounted for by adding an extra spin-dependent term to the Hamiltonian. These approximations are a logical extension of existing approaches to simulate the dynamics of fermions, which we review. In this paper, we discuss the details of the equations of motion and potentials that form eFF, and evaluate the ability of eFF to describe ground-state systems containing covalent, ionic, multicenter, and/or metallic bonds. We also summarize two eFF calculations previously reported on electronically excited systems: (1) the thermodynamics of hydrogen compressed up to ten times liquid density and heated up to 200 000 K; and (2) the dynamics of Auger fragmentation in a diamond nanoparticle, where hundreds of electron volts of excitation energy are dissipated over tens of femtoseconds. These cases represent the first steps toward using eFF to model highly excited electronic processes in complex materials.

  12. An impact excitation system for repeatable, high-bandwidth modal testing of miniature structures

    NASA Astrophysics Data System (ADS)

    Bediz, Bekir; Korkmaz, Emrullah; Burak Ozdoganlar, O.

    2014-06-01

    Miniature components and devices are increasingly seen in a myriad of applications. In general, the dynamic behavior of miniature devices is critical to their functionality and performance. However, modal testing of miniature structures poses many challenges. This paper presents a design and evaluation of an impact excitation system (IES) for repeatable, high-bandwidth, controlled-force modal testing of miniature structures. Furthermore, a dynamic model of the system is derived and experimentally validated to enable the identification of the system parameters that yield single-hit impacts with desired bandwidth and force magnitude. The system includes a small instrumented impact tip attached to a custom designed flexure-based body, an automated electromagnetic release mechanism, and various precision positioners. The excitation bandwidth and the impact force magnitude can be controlled by selecting the system parameters. The dynamic model of the system includes the structural dynamics of the flexure-based body, the electromagnetic force and the associated eddy-current damping, and the impact event. A validation study showed an excellent match between the model simulations and experiments in terms of impact force and bandwidth. The model is then used to create process maps that relate the system parameters to the number of hits (single vs. multiple), the impact force magnitudes and the excitation bandwidths. These process maps can be used to select system parameters or predict system response for a given set of parameters. A set of experiments is conducted to compare the performances of the IES and a (manual) miniature impact hammer. It is concluded that the IES significantly improves repeatability in terms of the impact bandwidth, location, and force magnitude, while providing a high excitation-bandwidth and excellent coherence values. The application of the IES is demonstrated through modal testing of a miniature contact-probe system.

  13. Discordance of the unified scheme with observed properties of quasars and high-excitation galaxies in the 3CRR sample

    SciTech Connect

    Singal, Ashok K.

    2014-07-01

    We examine the consistency of the unified scheme of Fanaroff-Riley type II radio galaxies and quasars with their observed number and size distributions in the 3CRR sample. We separate the low-excitation galaxies from the high-excitation ones, as the former might not harbor a quasar within and thus may not be partaking in the unified scheme models. In the updated 3CRR sample, at low redshifts (z < 0.5), the relative number and luminosity distributions of high-excitation galaxies and quasars roughly match the expectations from the orientation-based unified scheme model. However, a foreshortening in the observed sizes of quasars, which is a must in the orientation-based model, is not seen with respect to radio galaxies even when the low-excitation galaxies are excluded. This dashes the hope that the unified scheme might still work if one includes only the high-excitation galaxies.

  14. Probing highly obscured, self-absorbed galaxy nuclei with vibrationally excited HCN

    NASA Astrophysics Data System (ADS)

    Aalto, S.; Martín, S.; Costagliola, F.; González-Alfonso, E.; Muller, S.; Sakamoto, K.; Fuller, G. A.; García-Burillo, S.; van der Werf, P.; Neri, R.; Spaans, M.; Combes, F.; Viti, S.; Mühle, S.; Armus, L.; Evans, A.; Sturm, E.; Cernicharo, J.; Henkel, C.; Greve, T. R.

    2015-12-01

    We present high resolution (0.̋4) IRAM PdBI and ALMA mm and submm observations of the (ultra) luminous infrared galaxies ((U)LIRGs) IRAS 17208-0014, Arp220, IC 860 and Zw049.057 that reveal intense line emission from vibrationally excited (ν2 = 1) J = 3-2 and 4-3 HCN. The emission is emerging from buried, compact (r< 17-70 pc) nuclei that have very high implied mid-infrared surface brightness > 5 × 1013 L⊙ kpc-2. These nuclei are likely powered by accreting supermassive black holes (SMBHs) and/or hot (>200 K) extreme starbursts. Vibrational, ν2 = 1, lines of HCN are excited by intense 14 μm mid-infrared emission and are excellent probes of the dynamics, masses, and physical conditions of (U)LIRG nuclei when H2 column densities exceed 1024 cm-2. It is clear that these lines open up a new interesting avenue to gain access to the most obscured AGNs and starbursts. Vibrationally excited HCN acts as a proxy for the absorbed mid-infrared emission from the embedded nuclei, which allows for reconstruction of the intrinsic, hotter dust SED. In contrast, we show strong evidence that the ground vibrational state (ν = 0), J = 3-2and 4-3 rotational lines of HCN and HCO+ fail to probe the highly enshrouded, compact nuclear regions owing to strong self- and continuum absorption. The HCN and HCO+ line profiles are double-peaked because of the absorption and show evidence of non-circular motions - possibly in the form of in- or outflows. Detections of vibrationally excited HCN in external galaxies are so far limited to ULIRGs and early-type spiral LIRGs, and we discuss possible causes for this. We tentatively suggest that the peak of vibrationally excited HCN emission is connected to a rapid stage of nuclear growth, before the phase of strong feedback. Based on observations carried out with the IRAM Plateau de Bure and ALMA Interferometers. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). ALMA is a partnership of ESO (representing its member states

  15. High-resolution Valence and Core Excitation Spectra via First-Principles Calculations and Experiment

    NASA Astrophysics Data System (ADS)

    Shirley, Eric; Fossard, F.; Gilmore, K.; Hug, G.; Kas, J. J.; Rehr, J. J.; Vila, F.

    We calculate the optical and C K-edge near edge spectra of crystalline and molecular C60 measured with high-resolution electron energy-loss spectroscopy. The calculations are carried out using at least three different methods: Bethe-Salpeter calculations using the NIST Bethe-Salpeter Equation solver (NBSE) in the valence and OCEAN (Obtaining Core Excitation with Ab initio methods and NBSE) suite [Gilmore et al., Comp. Phys. Comm., (2015)]; excited-core-hole calculations using XCH [D. Prendergast and G. Galli, Phys. Rev. Lett. 96, 215502 (2006)]; and constrained occupancy using StoBe (Stockholm-Berlin core-excitation code) [StoBe-deMon version 3.0, K. Hermann et al. (2009)]. They include self-energy effects, lifetime-damping, and Debye-Waller effects. A comparison of spectral features to those observed illustrates the sensitivity of certain features to computation details (e.g., self-energy corrections and core-hole screening). This may point to limitations of various approximations, e.g. in conventional BSE paradigm and/or the incomplete treatment of vibrational effects. Supported in part by DOE BES Grant DE-FG03-97ER45623 (JJR, JJK, FV).

  16. Center mode of a doubly resonant optical periodic structure

    NASA Astrophysics Data System (ADS)

    Alagappan, G.; Png, C. E.

    2016-07-01

    An optical periodic structure with a single spatial resonance exhibits a stopband. When a second spatial resonance very close to the first one is added, the resulting doubly resonant structure exhibits a Gaussian enveloped, high quality factor transmission state right at the center of the original stopband. Using a slowly varying envelope approximation, we describe the optical characteristics of this transmission state analytically. The transmission state exists despite an optical structure of low refractive index contrast, and has potential applications in nano-optics, and photonics.

  17. Visible-light-excited and europium-emissive nanoparticles for highly-luminescent bioimaging in vivo.

    PubMed

    Wu, Yongquan; Shi, Mei; Zhao, Lingzhi; Feng, Wei; Li, Fuyou; Huang, Chunhui

    2014-07-01

    Europium(III)-based material showing special milliseconds photoluminescence lifetime has been considered as an ideal time-gated luminescence probe for bioimaging, but is still limited in application in luminescent small-animal bioimaging in vivo. Here, a water-soluble, stable, highly-luminescent nanosystem, Ir-Eu-MSN (MSN = mesoporous silica nanoparticles, Ir-Eu = [Ir(dfppy)2(pic-OH)]3Eu·2H2O, dfppy = 2-(2,4-difluorophenyl)pyridine, pic-OH = 3-hydroxy-2-carboxypyridine), was developed by an in situ coordination reaction to form an insoluble dinuclear iridium(III) complex-sensitized-europium(III) emissive complex within mesoporous silica nanoparticles (MSNs) which had high loading efficiency. Compared with the usual approach of physical adsorption, this in-situ reaction strategy provided 20-fold the loading efficiency (43.2%) of the insoluble Ir-Eu complex in MSNs. These nanoparticles in solid state showed bright red luminescence with high quantum yield of 55.2%, and the excitation window extended up to 470 nm. These Ir-Eu-MSN nanoparticles were used for luminescence imaging in living cells under excitation at 458 nm with confocal microscopy, which was confirmed by flow cytometry. Furthermore, the Ir-Eu-MSN nanoparticles were successfully applied into high-contrast luminescent lymphatic imaging in vivo under low power density excitation of 5 mW cm(-2). This synthetic method provides a universal strategy of combining hydrophobic complexes with hydrophilic MSNs for in vivo bioimaging.

  18. Effects of a Single Session of High Intensity Interval Treadmill Training on Corticomotor Excitability following Stroke: Implications for Therapy

    PubMed Central

    Stinear, James W.; Kanekar, Neeta

    2016-01-01

    Objective. High intensity interval treadmill training (HIITT) has been gaining popularity for gait rehabilitation after stroke. In this study, we examined the changes in excitability of the lower limb motor cortical representation (M1) in chronic stroke survivors following a single session of HIITT. We also determined whether exercise-induced changes in excitability could be modulated by transcranial direct current stimulation (tDCS) enhanced with a paretic ankle skill acquisition task. Methods. Eleven individuals with chronic stroke participated in two 40-minute treadmill-training sessions: HIITT alone and HITT preceded by anodal tDCS enhanced with a skill acquisition task (e-tDCS+HIITT). Transcranial magnetic stimulation (TMS) was used to assess corticomotor excitability of paretic and nonparetic tibialis anterior (TA) muscles. Results. HIIT alone reduced paretic TA M1 excitability in 7 of 11 participants by ≥ 10%. e-tDCS+HIITT increased paretic TA M1 excitability and decreased nonparetic TA M1 excitability. Conclusions. HIITT suppresses corticomotor excitability in some people with chronic stroke. When HIITT is preceded by tDCS in combination with a skill acquisition task, the asymmetry of between-hemisphere corticomotor excitability is reduced. Significance. This study provides preliminary data indicating that the cardiovascular benefits of HIITT may be achieved without suppressing motor excitability in some stroke survivors. PMID:27738524

  19. Excitation of azimuthal surface modes by relativistic flows of electrons in the high-frequency range

    SciTech Connect

    Girka, V. O.; Girka, I. O.; Pavlenko, I. V.

    2011-05-15

    Excitation of extraordinarily polarized azimuthal surface eigenwaves is shown to be possible in the frequency range above the upper hybrid resonance in waveguides with metal walls which are partially filled by cold magnetoactive plasma. Interaction of these waves with flows of electrons which rotate around the plasma column in the narrow gap separating the plasma from the wall of the waveguide is studied. Conditions of resonant interaction of the beam with the mentioned high-frequency azimuthal surface waves are shown by numerical methods to be reachable ones in the case of enough strong external magnetic fields without passing to the field of ultra-relativistic velocities of the beam.

  20. Ablation of GaAs by Intense, Ultrafast Electronic Excitation from Highly Charged Ions

    NASA Astrophysics Data System (ADS)

    Schenkel, T.; Hamza, A. V.; Barnes, A. V.; Schneider, D. H.; Banks, J. C.; Doyle, B. L.

    1998-09-01

    We have measured total ablation rates and secondary ion yields from undoped GaAs(100) interacting with slow \\(v = 6.6×105 m/s\\), very highly charged ions. Ablation rates increase strongly as a function of projectile charge. Some 1400 target atoms are removed when a single Th70+ ion deposits a potential energy of 152.6 keV within a few femtoseconds into a nanometer-sized target volume. We discuss models for ablation of semiconductors by intense, ultrafast electronic excitation.

  1. Ablation of GaAs by Intense, Ultrafast Electronic Excitation from Highly Charged Ions

    SciTech Connect

    Schenkel, T.; Hamza, A.V.; Barnes, A.V.; Schneider, D.H.; Banks, J.C.; Doyle, B.L.

    1998-09-01

    We have measured total ablation rates and secondary ion yields from undoped GaAs(100) interacting with slow (v=6.6{times}10{sup 5} m /s) , very highly charged ions. Ablation rates increase strongly as a function of projectile charge. Some 1400thinspthinsptarget atoms are removed when a single Th{sup 70+} ion deposits a potential energy of 152.6thinspthinspkeV within a few femtoseconds into a nanometer-sized target volume. We discuss models for ablation of semiconductors by intense, ultrafast electronic excitation. {copyright} {ital 1998} {ital The American Physical Society}

  2. Autoionization and ultrafast relaxation dynamics of highly excited states in N2

    NASA Astrophysics Data System (ADS)

    Lucchini, M.; Kim, K.; Calegari, F.; Kelkensberg, F.; Siu, W.; Sansone, G.; Vrakking, M. J. J.; Hochlaf, M.; Nisoli, M.

    2012-10-01

    We have used the velocity-map imaging (VMI) technique to measure autoionization dynamics in molecular nitrogen initiated by a train of attosecond pulses. The pump-probe measurements show clear evidence of a crossing between potential energy curves of the highly excited N2+ ion and of the N22+ ion. It is found that the autoionization becomes energetically allowed when the two nuclei are still very close (˜3 Å), in contrast with observations in other diatomic molecules, and that it can be coherently manipulated by a strong femtosecond infrared pulse.

  3. High electronic excitations and ion beam mixing effects in high energy ion irradiated Fe/Si multilayers

    SciTech Connect

    Bauer, P.; Dufour, C.; Jaouen, C.; Marchal, G.; Pacaud, J.; Grilhe, J.; Jousset, J.C.

    1997-01-01

    M{umlt o}ssbauer spectroscopy ({sup 57}Fe) shows evidence for mixing effects induced by electronic energy deposition in nanoscale Fe/Si multilayers irradiated with swift heavy ions. A decrease in the mixing efficiency with electronic stopping power is reported; a threshold is found, under which iron environment modifications no longer occur. The kinetics of Fe{endash}Si phase formation after irradiation suggests the existence of three regimes: (i) for high excitation levels, a magnetic amorphous phase is formed directly in the wake of the incoming ion and an almost complete mixing is reached at low fluence (10{sup 13} U/cm{sup 2}); (ii) for low excitation levels, a paramagnetic Si-rich amorphous phase is favored at the interface while crystalline iron subsists at high fluences; (iii) for intermediate excitation levels, saturation effects are observed and the formation rate of both magnetic and paramagnetic phases points to direct mixing in the ion wake but with a reduced track length in comparison to U irradiation. The measured interfacial mixing cross section induced by electronic energy deposition suggests that a thermal diffusion process is mainly involved in addition to damage creation. {copyright} {ital 1997 American Institute of Physics.}

  4. Radiative cascade of highly excited hydrogen atoms in strong magnetic fields

    SciTech Connect

    Topcu, Tuerker; Robicheaux, Francis

    2006-04-15

    We have studied the radiative decay of atomic hydrogen in strong magnetic fields of up to 4 T. We have followed the radiative cascade from completely l,m mixed distributions of highly excited states as well as from distributions that involve highly excited states with |m|{approx}n. We have found that the time it takes to populate the ground state is not affected by the magnetic field for the initial states with n < or approx. 20. For higher n manifolds, the electrons in the most negative m states are substantially slowed down by the magnetic field resulting in a much longer lifetime. We show that less than 10% of the antihydrogen atoms with n{approx}35 generated in antihydrogen experiments at 4 K will decay to their ground states before they hit the wall of the vacuum container unless they are trapped. We have also found that the decay time is mainly determined by the fraction of atoms that were initially in highest negative m states due to the fact that only {delta}m+{delta}{pi}=1 transitions are allowed in the magnetic field. We give a semiclassical method for calculating the decay rates for circular states and show that when the initial states have high-m, semiclassical rates agree with the full quantum mechanical rates within a couple of percent for states with effective n > or approx. 20.

  5. High power visible light emitting diodes as pulsed excitation sources for biomedical photoacoustics.

    PubMed

    Allen, Thomas J; Beard, Paul C

    2016-04-01

    The use of visible light emitting diodes (LEDs) as an alternative to Q-switched lasers conventionally used as photoacoustic excitation sources has been explored. In common with laser diodes, LEDs offer the advantages of compact size, low cost and high efficiency. However, laser diodes suitable for pulsed photoacoustic generation are typically available only at wavelengths greater than 750nm. By contrast, LEDs are readily available at visible wavelengths below 650nm where haemoglobin absorption is significantly higher, offering the prospect of increased SNR for superficial vascular imaging applications. To demonstrate feasibility, a range of low cost commercially available LEDs operating in the 420-620nm spectral range were used to generate photoacoustic signals in physiologically realistic vascular phantoms. Overdriving with 200ns pulses and operating at a low duty cycle enabled pulse energies up to 10µJ to be obtained with a 620nm LED. By operating at a high pulse repetition frequency (PRF) in order to rapidly signal average over many acquisitions, this pulse energy was sufficient to generate detectable signals in a blood filled tube immersed in an Intralipid suspension (µs' = 1mm(-1)) at a depth of 15mm using widefield illumination. In addition, a compact four-wavelength LED (460nm, 530nm, 590nm, 620nm) in conjunction with a coded excitation scheme was used to illustrate rapid multiwavelength signal acquisition for spectroscopic applications. This study demonstrates that LEDs could find application as inexpensive and compact multiwavelength photoacoustic excitation sources for imaging superficial vascular anatomy. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. PMID:27446652

  6. High power visible light emitting diodes as pulsed excitation sources for biomedical photoacoustics

    PubMed Central

    Allen, Thomas J.; Beard, Paul C.

    2016-01-01

    The use of visible light emitting diodes (LEDs) as an alternative to Q-switched lasers conventionally used as photoacoustic excitation sources has been explored. In common with laser diodes, LEDs offer the advantages of compact size, low cost and high efficiency. However, laser diodes suitable for pulsed photoacoustic generation are typically available only at wavelengths greater than 750nm. By contrast, LEDs are readily available at visible wavelengths below 650nm where haemoglobin absorption is significantly higher, offering the prospect of increased SNR for superficial vascular imaging applications. To demonstrate feasibility, a range of low cost commercially available LEDs operating in the 420-620nm spectral range were used to generate photoacoustic signals in physiologically realistic vascular phantoms. Overdriving with 200ns pulses and operating at a low duty cycle enabled pulse energies up to 10µJ to be obtained with a 620nm LED. By operating at a high pulse repetition frequency (PRF) in order to rapidly signal average over many acquisitions, this pulse energy was sufficient to generate detectable signals in a blood filled tube immersed in an Intralipid suspension (µs’ = 1mm−1) at a depth of 15mm using widefield illumination. In addition, a compact four-wavelength LED (460nm, 530nm, 590nm, 620nm) in conjunction with a coded excitation scheme was used to illustrate rapid multiwavelength signal acquisition for spectroscopic applications. This study demonstrates that LEDs could find application as inexpensive and compact multiwavelength photoacoustic excitation sources for imaging superficial vascular anatomy. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. PMID:27446652

  7. High power visible light emitting diodes as pulsed excitation sources for biomedical photoacoustics.

    PubMed

    Allen, Thomas J; Beard, Paul C

    2016-04-01

    The use of visible light emitting diodes (LEDs) as an alternative to Q-switched lasers conventionally used as photoacoustic excitation sources has been explored. In common with laser diodes, LEDs offer the advantages of compact size, low cost and high efficiency. However, laser diodes suitable for pulsed photoacoustic generation are typically available only at wavelengths greater than 750nm. By contrast, LEDs are readily available at visible wavelengths below 650nm where haemoglobin absorption is significantly higher, offering the prospect of increased SNR for superficial vascular imaging applications. To demonstrate feasibility, a range of low cost commercially available LEDs operating in the 420-620nm spectral range were used to generate photoacoustic signals in physiologically realistic vascular phantoms. Overdriving with 200ns pulses and operating at a low duty cycle enabled pulse energies up to 10µJ to be obtained with a 620nm LED. By operating at a high pulse repetition frequency (PRF) in order to rapidly signal average over many acquisitions, this pulse energy was sufficient to generate detectable signals in a blood filled tube immersed in an Intralipid suspension (µs' = 1mm(-1)) at a depth of 15mm using widefield illumination. In addition, a compact four-wavelength LED (460nm, 530nm, 590nm, 620nm) in conjunction with a coded excitation scheme was used to illustrate rapid multiwavelength signal acquisition for spectroscopic applications. This study demonstrates that LEDs could find application as inexpensive and compact multiwavelength photoacoustic excitation sources for imaging superficial vascular anatomy. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

  8. Millimeter- and submillimeter-wave spectrum of highly excited states of water. [in interstellar medium and late stars

    NASA Technical Reports Server (NTRS)

    Pearson, J. C.; De Lucia, Frank C.; Anderson, Todd; Herbst, Eric; Helminger, Paul

    1991-01-01

    To facilitate studies of water in the interstellar medium and late-type stars, the frequencies of 30 new millimeter- and submillimeter-wave transitions of H2O-16 have been measured, which lie between 100 GHz and 600 GHz. This represents almost a doubling of the number of water lines that have been observed in the laboratory in this spectral region at high resolution. All of the newly observed lines are highly excited, lying between 2400 and 4200/cm above the ground level. Some of these have large excitation energies because of their high rotational states and others because they lie in excited vibrational states. These lines are potentially of substantial astrophysical significance because they are related to the study of interstellar masers and because their high excitation eliminates the atmospheric self-absorption associated with the more well-known water lines.

  9. Structural health monitoring by high-frequency vibration measurement with non-contact laser excitation

    NASA Astrophysics Data System (ADS)

    Kajiwara, I.; Miyamoto, D.; Hosoya, N.; Nishidome, C.

    2011-04-01

    This paper proposes a vibration testing and health monitoring system based on an impulse response excited by a laser ablation. High power YAG pulse laser is used for producing an ideal impulse force on structural surface. It is possible to measure high frequency vibration responses in this system. A health monitoring system is constructed by this vibration testing system and a damage detecting algorithm. A microscopic damage of structures can be extracted by detecting fluctuations of high frequency vibration response with the present health monitoring system. In this study, loosening of bolt tightening torques is defined as the damage of the system. The damage is detected and identified by statistical evaluations with Recognition-Taguchi method.

  10. Effect of collective response on electron capture and excitation in collisions of highly charged ions with fullerenes.

    PubMed

    Kadhane, U; Misra, D; Singh, Y P; Tribedi, Lokesh C

    2003-03-01

    Projectile deexcitation Lyman x-ray emission following electron capture and K excitation has been studied in collisions of bare and Li-like sulphur ions (of energy 110 MeV) with fullerenes (C(60)/C(70)) and different gaseous targets. The intensity ratios of different Lyman x-ray lines in collisions with fullerenes are found to be substantially lower than those for the gas targets, both for capture and excitation. This has been explained in terms of a model based on "solidlike" effect, namely, wakefield induced stark mixing of the excited states populated via electron capture or K excitation: a collective phenomenon of plasmon excitation in the fullerenes under the influence of heavy, highly charged ions.

  11. Effect of collective response on electron capture and excitation in collisions of highly charged ions with fullerenes.

    PubMed

    Kadhane, U; Misra, D; Singh, Y P; Tribedi, Lokesh C

    2003-03-01

    Projectile deexcitation Lyman x-ray emission following electron capture and K excitation has been studied in collisions of bare and Li-like sulphur ions (of energy 110 MeV) with fullerenes (C(60)/C(70)) and different gaseous targets. The intensity ratios of different Lyman x-ray lines in collisions with fullerenes are found to be substantially lower than those for the gas targets, both for capture and excitation. This has been explained in terms of a model based on "solidlike" effect, namely, wakefield induced stark mixing of the excited states populated via electron capture or K excitation: a collective phenomenon of plasmon excitation in the fullerenes under the influence of heavy, highly charged ions. PMID:12689221

  12. Green laser excited surface plasmon resonance biosensor utilizing highly sensitive phase interrogation detection

    NASA Astrophysics Data System (ADS)

    Chen, How-Foo; Hsu, Wei-Chen; Wang, Ya-Jung; Yen, Ta-Jen

    2010-04-01

    Surface plasmon resonance (SPR) biosensors have been widely used for dynamical analysis of molecular affinity, bacterium screening, and drug discovery due to its advantages of label-free detection, dynamic interaction analysis, small sample volume, and ultra sensitivity (feasibility of single molecular detection). Recently, SPR biosensing for cell imaging known as SPR microscopy (SPRM) has attracted great attention due to the characteristics of SPR biosensors. However, it is well known that the trends of sensitivity and spatial resolution are opposite to each other: Surface plasmon waves (SPWs) with shorter wavelength which provides higher spatial resolution has less sensitivity. It is known that the spatial resolution of SPRM is limited by the propagation length of surface plasmon wave (SPW) along the metaldielectric interface. SPW excited by 632.8 nm light has the propagation length of 3 um. This length becomes longer when a longer wavelength is selected. While most of SPR biosensors are built with 632.8 nm or longer wavelength for high sensitivity, using 532nm light to excite SPWs is desired for submicron resolution since the propagation length is around 150 nm. Different from current phase interrogation methods, the proposed phase interrogation method is highly sensitive and suitable for CCD imaging. Although it is generally believed that SPWs with wavelength 532nm has poor sensitivity, the experimental result showed that the setup can reach the sensitivity lower than 2×10-6 RIU when sucrose is used as the test sample.

  13. Trajectory study of supercollision relaxation in highly vibrationally excited pyrazine and CO2.

    PubMed

    Li, Ziman; Sansom, Rebecca; Bonella, Sara; Coker, David F; Mullin, Amy S

    2005-09-01

    Classical trajectory calculations were performed to simulate state-resolved energy transfer experiments of highly vibrationally excited pyrazine (E(vib) = 37,900 cm(-1)) and CO(2), which were conducted using a high-resolution transient infrared absorption spectrometer. The goal here is to use classical trajectories to simulate the supercollision energy transfer pathway wherein large amounts of energy are transferred in single collisions in order to compare with experimental results. In the trajectory calculations, Newton's laws of motion are used for the molecular motion, isolated molecules are treated as collections of harmonic oscillators, and intermolecular potentials are formed by pairwise Lennard-Jones potentials. The calculations qualitatively reproduce the observed energy partitioning in the scattered CO(2) molecules and show that the relative partitioning between bath rotation and translation is dependent on the moment of inertia of the bath molecule. The simulations show that the low-frequency modes of the vibrationally excited pyrazine contribute most to the strong collisions. The majority of collisions lead to small DeltaE values and primarily involve single encounters between the energy donor and acceptor. The large DeltaE exchanges result from both single impulsive encounters and chattering collisions that involve multiple encounters.

  14. A system for optical high resolution screening of electrical excitable cells.

    PubMed

    Müller, Oliver; Tian, Qinghai; Zantl, Roman; Kahl, Valentin; Lipp, Peter; Kaestner, Lars

    2010-03-01

    The application of primary excitable cells for high content screening (HCS) requires a multitude of novel developments including cell culture and multi-well plates. Here we introduce a novel system combining optimised culture conditions of primary adult cardiomyocytes with the particular needs of excitable cells for arbitrary field stimulation of individual wells. The major advancements of our design were tested in calcium imaging experiments and comprise (i) each well of the plate can be subjected to individual pulse protocols, (ii) the software driving electrical stimulation can run as a stand-alone application but also as a plug-in in HCS software packages, (iii) the optical properties of the plastic substrate (foil) resemble those of glass coverslips fostering high resolution immersion-based microscopy, (iv) the bottom of the foil is coated with an oleophobic layer that prevents immersion oil from sticking, (v) the top of the foil is coated with an elastic film. The latter enables cardiomyocytes to display loaded contractions by mimicking the physiologically occurring local elastic network (e.g. extracellular matrix) and results in significantly increased contractions (with identical calcium transients) when compared to non-elastic substrates. Thus, our novel design and culture conditions represent an essential further step towards the application of primary cultured adult cardiomyocytes for HCS applications. PMID:20036001

  15. Theoretical studies of collisional relaxation of highly excited SO{sub 2} in an Ar bath

    SciTech Connect

    Lendvay, G.; Schatz, G.C.; Harding, L.B.

    1995-12-31

    This paper describes molecular dynamics studies of collisional relaxation of highly excited SO{sub 2} in an Ar bath. Most of the calculations use a newly developed global ab initio potential surface for SO{sub 2} that correctly describes the superoxide (SOO) and ring isomers of SO{sub 2} that occur as secondary minima on the ground state potential surface at high energies (about 75% of the dissociation energy) above the C{sub 2v} minimum. Rate constants for the S + O{sub 2} and O + SO reactions are calculated to test this surface, and to examine the importance of electronically excited states in the O + SO recombination. The Ar + SO{sub 2} collisions are described by summing the ab initio potential with empirical intermolecular potentials. The resulting average vibrational energy transfer <{Delta}E> per collision is in good agreement with direct measurements (done at energies where the secondary minima are not populated) at 1000K, but the agreement is poorer at 300K. The agreement is significantly better than was obtained in a previous theoretical study, and our results indicate that the use of improved intramolecular and intermolecular potentials is crucial to obtaining the better results. The energy dependence of <{Delta}E> is found to be much stronger at energies where the secondary minima on the potential surface are accessible, however much of this effect is reproduced using a potential that has the same dissociation energy but not the secondary minima.

  16. High visual demand following theta burst stimulation modulates the effect on visual cortex excitability

    PubMed Central

    Brückner, Sabrina; Kammer, Thomas

    2015-01-01

    Modulatory effects of repetitive transcranial magnetic stimulation (TMS) depend on the activity of the stimulated cortical area before, during, and even after application. In the present study, we investigated the effects of theta burst stimulation (TBS) on visual cortex excitability using phosphene threshold (PTs). In a between-group design either continuous or intermittent TBS was applied with 100% of individual PT intensity. We varied visual demand following stimulation in form of high demand (acuity task) or low demand (looking at the wall). No change of PTs was observed directly after TBS. We found increased PTs only if subjects had high visual demand following continuous TBS. With low visual demand following stimulation no change of PT was observed. Intermittent TBS had no effect on visual cortex excitability at all. Since other studies showed increased PTs following continuous TBS using subthreshold intensities, our results highlight the importance of stimulation intensity applying TBS to the visual cortex. Furthermore, the state of the neurons in the stimulated cortex area not only before but also following TBS has an important influence on the effects of stimulation, making it necessary to scrupulously control for activity during the whole experimental session in a study. PMID:26578935

  17. High spectral specificity of local chemical components characterization with multichannel shift-excitation Raman spectroscopy

    PubMed Central

    Chen, Kun; Wu, Tao; Wei, Haoyun; Wu, Xuejian; Li, Yan

    2015-01-01

    Raman spectroscopy has emerged as a promising tool for its noninvasive and nondestructive characterization of local chemical structures. However, spectrally overlapping components prevent the specific identification of hyperfine molecular information of different substances, because of limitations in the spectral resolving power. The challenge is to find a way of preserving scattered photons and retrieving hidden/buried Raman signatures to take full advantage of its chemical specificity. Here, we demonstrate a multichannel acquisition framework based on shift-excitation and slit-modulation, followed by mathematical post-processing, which enables a significant improvement in the spectral specificity of Raman characterization. The present technique, termed shift-excitation blind super-resolution Raman spectroscopy (SEBSR), uses multiple degraded spectra to beat the dispersion-loss trade-off and facilitate high-resolution applications. It overcomes a fundamental problem that has previously plagued high-resolution Raman spectroscopy: fine spectral resolution requires large dispersion, which is accompanied by extreme optical loss. Applicability is demonstrated by the perfect recovery of fine structure of the C-Cl bending mode as well as the clear discrimination of different polymorphs of mannitol. Due to its enhanced discrimination capability, this method offers a feasible route at encouraging a broader range of applications in analytical chemistry, materials and biomedicine. PMID:26350355

  18. A model for energy transfer in collisions of atoms with highly excited molecules.

    PubMed

    Houston, Paul L; Conte, Riccardo; Bowman, Joel M

    2015-05-21

    A model for energy transfer in the collision between an atom and a highly excited target molecule has been developed on the basis of classical mechanics and turning point analysis. The predictions of the model have been tested against the results of trajectory calculations for collisions of five different target molecules with argon or helium under a variety of temperatures, collision energies, and initial rotational levels. The model predicts selected moments of the joint probability distribution, P(Jf,ΔE) with an R(2) ≈ 0.90. The calculation is efficient, in most cases taking less than one CPU-hour. The model provides several insights into the energy transfer process. The joint probability distribution is strongly dependent on rotational energy transfer and conservation laws and less dependent on vibrational energy transfer. There are two mechanisms for rotational excitation, one due to motion normal to the intermolecular potential and one due to motion tangential to it and perpendicular to the line of centers. Energy transfer is found to depend strongly on the intermolecular potential and only weakly on the intramolecular potential. Highly efficient collisions are a natural consequence of the energy transfer and arise due to collisions at "sweet spots" in the space of impact parameter and molecular orientation. PMID:25907301

  19. Unraveling the excitation mechanisms of highly oblique lower band chorus waves

    NASA Astrophysics Data System (ADS)

    Li, W.; Mourenas, D.; Artemyev, A. V.; Bortnik, J.; Thorne, R. M.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Reeves, G. D.; Funsten, H. O.; Spence, H. E.

    2016-09-01

    Excitation mechanisms of highly oblique, quasi-electrostatic lower band chorus waves are investigated using Van Allen Probes observations near the equator of the Earth's magnetosphere. Linear growth rates are evaluated based on in situ, measured electron velocity distributions and plasma conditions and compared with simultaneously observed wave frequency spectra and wave normal angles. Accordingly, two distinct excitation mechanisms of highly oblique lower band chorus have been clearly identified for the first time. The first mechanism relies on cyclotron resonance with electrons possessing both a realistic temperature anisotropy at keV energies and a plateau at 100-500 eV in the parallel velocity distribution. The second mechanism corresponds to Landau resonance with a 100-500 eV beam. In both cases, a small low-energy beam-like component is necessary for suppressing an otherwise dominating Landau damping. Our new findings suggest that small variations in the electron distribution could have important impacts on energetic electron dynamics.

  20. A system for optical high resolution screening of electrical excitable cells.

    PubMed

    Müller, Oliver; Tian, Qinghai; Zantl, Roman; Kahl, Valentin; Lipp, Peter; Kaestner, Lars

    2010-03-01

    The application of primary excitable cells for high content screening (HCS) requires a multitude of novel developments including cell culture and multi-well plates. Here we introduce a novel system combining optimised culture conditions of primary adult cardiomyocytes with the particular needs of excitable cells for arbitrary field stimulation of individual wells. The major advancements of our design were tested in calcium imaging experiments and comprise (i) each well of the plate can be subjected to individual pulse protocols, (ii) the software driving electrical stimulation can run as a stand-alone application but also as a plug-in in HCS software packages, (iii) the optical properties of the plastic substrate (foil) resemble those of glass coverslips fostering high resolution immersion-based microscopy, (iv) the bottom of the foil is coated with an oleophobic layer that prevents immersion oil from sticking, (v) the top of the foil is coated with an elastic film. The latter enables cardiomyocytes to display loaded contractions by mimicking the physiologically occurring local elastic network (e.g. extracellular matrix) and results in significantly increased contractions (with identical calcium transients) when compared to non-elastic substrates. Thus, our novel design and culture conditions represent an essential further step towards the application of primary cultured adult cardiomyocytes for HCS applications.

  1. 20 {mu}s isomeric state in doubly odd {sub 61}{sup 134}Pm

    SciTech Connect

    Cullen, D. M.; Mason, P. J. R; Rigby, S. V.; Kishada, A. M.; Varley, B. J.; Scholey, C.; Eeckhaudt, S.; Grahn, T.; Greenlees, P. T.; Jakobsson, U.; Jones, P. M.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Leppaenen, A.-P.; Maentyniemi, K.; Nieminen, P.; Nyman, M.; Pakarinen, J.

    2009-08-15

    Recoil-isomer tagging at the Accelerator Laboratory of the University of Jyvaeskylae has been used to establish the isomeric nature of a known (7{sup -}) excited state in the doubly odd nucleus {sup 134}Pm. The isomeric state was determined to have a half-life of 20(1) {mu}s and was populated from the decay of a {pi}h{sub 11/2} x {nu}h{sub 11/2} band using the {sup 92}Mo({sup 54}Fe,2{alpha}3pn) reaction at 305 and 315 MeV. The isomer decays by a 71-keV transition that provides an intermediate step in linking the established {sup 134}Pm high-spin level scheme to the lower-spin states observed from the {beta} decay of {sup 134}Sm. Electron-conversion analysis for the 71-keV {gamma}-ray transition reveals that it is of E1 character and its small reduced-transition probability suggests that {sup 134}Pm may have a nuclear shape more rigid than that of the neighboring nuclei.

  2. Predicting the effect of angular momentum on the dissociation dynamics of highly rotationally excited radical intermediates

    SciTech Connect

    Brynteson, Matthew D.; Butler, Laurie J.

    2015-02-07

    We present a model which accurately predicts the net speed distributions of products resulting from the unimolecular decomposition of rotationally excited radicals. The radicals are produced photolytically from a halogenated precursor under collision-free conditions so they are not in a thermal distribution of rotational states. The accuracy relies on the radical dissociating with negligible energetic barrier beyond the endoergicity. We test the model predictions using previous velocity map imaging and crossed laser-molecular beam scattering experiments that photolytically generated rotationally excited CD{sub 2}CD{sub 2}OH and C{sub 3}H{sub 6}OH radicals from brominated precursors; some of those radicals then undergo further dissociation to CD{sub 2}CD{sub 2} + OH and C{sub 3}H{sub 6} + OH, respectively. We model the rotational trajectories of these radicals, with high vibrational and rotational energy, first near their equilibrium geometry, and then by projecting each point during the rotation to the transition state (continuing the rotational dynamics at that geometry). This allows us to accurately predict the recoil velocity imparted in the subsequent dissociation of the radical by calculating the tangential velocities of the CD{sub 2}CD{sub 2}/C{sub 3}H{sub 6} and OH fragments at the transition state. The model also gives a prediction for the distribution of angles between the dissociation fragments’ velocity vectors and the initial radical’s velocity vector. These results are used to generate fits to the previously measured time-of-flight distributions of the dissociation fragments; the fits are excellent. The results demonstrate the importance of considering the precession of the angular velocity vector for a rotating radical. We also show that if the initial angular momentum of the rotating radical lies nearly parallel to a principal axis, the very narrow range of tangential velocities predicted by this model must be convoluted with a J = 0 recoil

  3. Scaling of collision strengths for highly-excited states of ions of the H- and He-like sequences

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    Emission lines from highly-excited states (n ≥ 5) of H- and He-like ions have been detected in astrophysical sources and fusion plasmas. For such excited states, R-matrix or distorted wave calculations for electron-impact excitation are very limited, due to the large size of the atomic basis set needed to describe them. Calculations for n ≥ 6 are also not generally available. We study the behaviour of the electron-impact excitation collision strengths and effective collision strengths for the most important transitions used to model electron collision dominated astrophysical plasmas, solar, for example. We investigate the dependence on the relevant parameters: the principal quantum number n or the nuclear charge Z. We also estimate the importance of coupling to highly-excited states and the continuum by comparing the results of different sized calculations. We provide analytic formulae to calculate the electron-impact excitation collision strengths and effective collision strengths to highly-excited states (n ≥ 8) of H- and He-like ions. These extrapolated effective collision strengths can be used to interpret astrophysical and fusion plasma via collisional-radiative modelling. Tables of atomic data for Si xiii and S xv are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A135

  4. Pressure-induced emergence of unusually high-frequency transverse excitations in a liquid alkali metal: Evidence of two types of collective excitations contributing to the transverse dynamics at high pressures

    SciTech Connect

    Bryk, Taras; Ruocco, G.; Scopigno, T.

    2015-09-14

    Unlike phonons in crystals, the collective excitations in liquids cannot be treated as propagation of harmonic displacements of atoms around stable local energy minima. The viscoelasticity of liquids, reflected in transition from the adiabatic to elastic high-frequency speed of sound and in absence of the long-wavelength transverse excitations, results in dispersions of longitudinal (L) and transverse (T) collective excitations essentially different from the typical phonon ones. Practically, nothing is known about the effect of high pressure on the dispersion of collective excitations in liquids, which causes strong changes in liquid structure. Here dispersions of L and T collective excitations in liquid Li in the range of pressures up to 186 GPa were studied by ab initio simulations. Two methodologies for dispersion calculations were used: direct estimation from the peak positions of the L/T current spectral functions and simulation-based calculations of wavenumber-dependent collective eigenmodes. It is found that at ambient pressure, the longitudinal and transverse dynamics are well separated, while at high pressures, the transverse current spectral functions, density of vibrational states, and dispersions of collective excitations yield evidence of two types of propagating modes that contribute strongly to transverse dynamics. Emergence of the unusually high-frequency transverse modes gives evidence of the breakdown of a regular viscoelastic theory of transverse dynamics, which is based on coupling of a single transverse propagating mode with shear relaxation. The explanation of the observed high-frequency shift above the viscoelastic value is given by the presence of another branch of collective excitations. With the pressure increasing, coupling between the two types of collective excitations is rationalized within a proposed extended viscoelastic model of transverse dynamics.

  5. Excited baryon form-factors at high momentum transfer at CEBAF at higher energies

    SciTech Connect

    Stoler, P.

    1994-04-01

    The possibilities of measuring the properties of excited nucleons at high Q{sup 2} by means of exclusive single meson production at CEBAF with an electron energy of 8 GeV is considered. The motivation is to access short range phenomena in baryon structure, and to investigate the transition from the low Q{sup 2} non-perturbative QCD regime, where constituent quark models are valid, to higher Q{sup 2} where it is believed perturbative QCD plays an increasingly important role. It is found that high quality baryon decay angular distributions can be obtained for the most prominent states up to Q{sup 2} {approximately} 12 GeV{sup 2}/c{sup 2} using a set of moderate resolution, large solid angle magnetic spectrometers.

  6. Revealing the high-energy electronic excitations underlying the onset of high-temperature superconductivity in cuprates

    PubMed Central

    Giannetti, Claudio; Cilento, Federico; Conte, Stefano Dal; Coslovich, Giacomo; Ferrini, Gabriele; Molegraaf, Hajo; Raichle, Markus; Liang, Ruixing; Eisaki, Hiroshi; Greven, Martin; Damascelli, Andrea; van der Marel, Dirk; Parmigiani, Fulvio

    2011-01-01

    In strongly correlated systems the electronic properties at the Fermi energy (EF) are intertwined with those at high-energy scales. One of the pivotal challenges in the field of high-temperature superconductivity (HTSC) is to understand whether and how the high-energy scale physics associated with Mott-like excitations (|E−EF|>1 eV) is involved in the condensate formation. Here, we report the interplay between the many-body high-energy CuO2 excitations at 1.5 and 2 eV, and the onset of HTSC. This is revealed by a novel optical pump-supercontinuum-probe technique that provides access to the dynamics of the dielectric function in Bi2Sr2Ca0.92Y0.08Cu2O8+δ over an extended energy range, after the photoinduced suppression of the superconducting pairing. These results unveil an unconventional mechanism at the base of HTSC both below and above the optimal hole concentration required to attain the maximum critical temperature (Tc). PMID:21673674

  7. ATOMIC AND MOLECULAR PHYSICS: Experimental study of highly excited even-parity bound states of the Sm atom

    NASA Astrophysics Data System (ADS)

    Qin, Wen-Jie; Dai, Chang-Jian; Xiao, Ying; Zhao, Hong-Ying

    2009-08-01

    In this work, a three-step autoionization detection method and direct photoionization detection method are employed to measure the highly excited even-parity states of the Sm atom in the energy region between 36360 cm-1 and 40800 cm-1. Comparisons between the results from the two detection techniques enable us to discriminate the Rydberg states from the valence states in the same energy region with the information of level energies, possible J values and their relative intensities. Furthermore, in the experiment two different excitation schemes are designed to obtain the spectra of highly excited even-parity states of the Sm atom. With a detailed analysis of the experimental data, this work not only confirms the results about many spectral data from the literature with different excitation schemes, but also reports new spectral data on 29 Rydberg states and 23 valence states.

  8. Nonadiabtic electron dynamics in densely quasidegenerate states in highly excited boron cluster.

    PubMed

    Yonehara, Takehiro; Takatsuka, Kazuo

    2016-04-28

    Following the previous study on nonadiabatic reaction dynamics including boron clusters [T. Yonehara and K. Takatsuka, J. Chem. Phys. 137, 22A520 (2012)], we explore deep into highly excited electronic states of the singlet boron cluster (B12) to find the characteristic features of the densely quasi-degenerate electronic state manifold, which undergo very frequent nonadiabatic transitions and thereby intensive electronic state mixing among very many of the relevant states. So much so, isolating the individual adiabatic states and tracking the expected potential energy surfaces both lose the physical sense. This domain of molecular situation is far beyond the realm of the Born-Oppenheimer approximation. To survey such a violent electronic state-mixing, we apply a method of nonadiabatic electron wavepacket dynamics, the semiclassical Ehrenfest method. We have tracked those electron wavepackets and found the electronic state mixing looks like an ultrafast diffusion in the Hilbert space, which results in huge fluctuation. Furthermore, due to such a violent mixing, the quantum phases associated with the electronic states are swiftly randomized, and consequently the coherence among the electronic states are lost quickly. Besides, these highly excited states are mostly of highly poly-radical nature, even in the spin singlet manifold and the number of radicals amounts up to 10 electrons in the sense of unpaired electrons. Thus the electronic states are summarized to be poly-radical and decoherent with huge fluctuation in shorter time scales of vibrational motions. The present numerical study sets a theoretical foundation for unknown molecular properties and chemical reactivity of such densely quasi-degenerate chemical species. PMID:27131547

  9. Nonadiabtic electron dynamics in densely quasidegenerate states in highly excited boron cluster

    NASA Astrophysics Data System (ADS)

    Yonehara, Takehiro; Takatsuka, Kazuo

    2016-04-01

    Following the previous study on nonadiabatic reaction dynamics including boron clusters [T. Yonehara and K. Takatsuka, J. Chem. Phys. 137, 22A520 (2012)], we explore deep into highly excited electronic states of the singlet boron cluster (B12) to find the characteristic features of the densely quasi-degenerate electronic state manifold, which undergo very frequent nonadiabatic transitions and thereby intensive electronic state mixing among very many of the relevant states. So much so, isolating the individual adiabatic states and tracking the expected potential energy surfaces both lose the physical sense. This domain of molecular situation is far beyond the realm of the Born-Oppenheimer approximation. To survey such a violent electronic state-mixing, we apply a method of nonadiabatic electron wavepacket dynamics, the semiclassical Ehrenfest method. We have tracked those electron wavepackets and found the electronic state mixing looks like an ultrafast diffusion in the Hilbert space, which results in huge fluctuation. Furthermore, due to such a violent mixing, the quantum phases associated with the electronic states are swiftly randomized, and consequently the coherence among the electronic states are lost quickly. Besides, these highly excited states are mostly of highly poly-radical nature, even in the spin singlet manifold and the number of radicals amounts up to 10 electrons in the sense of unpaired electrons. Thus the electronic states are summarized to be poly-radical and decoherent with huge fluctuation in shorter time scales of vibrational motions. The present numerical study sets a theoretical foundation for unknown molecular properties and chemical reactivity of such densely quasi-degenerate chemical species.

  10. Herschel/HIFI observation of highly excited rotational lines of HNC toward IRC +10 216

    NASA Astrophysics Data System (ADS)

    Daniel, F.; Agúndez, M.; Cernicharo, J.; De Beck, E.; Lombaert, R.; Decin, L.; Kahane, C.; Guélin, M.; Müller, H. S. P.

    2012-06-01

    We report the detection in emission of various highly excited rotational transitions of HNC (J = 6-5 through J = 12-11) toward the carbon-star envelope IRC +10 216 using the HIFI instrument on-board the Herschel Space Observatory. Observations of the J = 1-0 and J = 3-2 lines of HNC with the IRAM 30-m telescope are also presented. The lines observed with HIFI have upper level energies corresponding to temperatures between 90 and 340 degrees Kelvin, and trace a warm and smaller circumstellar region than that seen in the interferometric maps of the J = 1-0 transition, whose emission extends up to a radius of 20''. After a detailed chemical and radiative transfer modeling, we find that the presence of HNC in the circumstellar envelope of IRC +10 216 is consistent with formation from the precursor ion HCNH+, which in turn is produced through several proton transfer reactions which are triggered by cosmic-ray ionization. We also find that the radiative pumping through λ 21 μm photons to the first excited state of the bending mode ν2 plays a crucial role to populate the high-J HNC levels involved in the transitions observed with HIFI. Emission in these high-J rotational transitions of HNC is expected to be strong in regions which are warm and dense and/or have an intense infrared flux at wavelengths around 21 μm. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Based on observations carried out with the IRAM 30-m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).

  11. High-sensitivity DNA detection with a laser-excited confocal fluorescence gel scanner.

    PubMed

    Quesada, M A; Rye, H S; Gingrich, J C; Glazer, A N; Mathies, R A

    1991-05-01

    A high-sensitivity, laser-excited confocal fluorescence gel scanner has been developed and applied to the detection of fluorescently labeled DNA. An argon ion laser (1-10 mW at 488 nm) is focused in the gel with a high-numerical aperture microscope objective. The laser-excited fluorescence is gathered by the objective and focused on a confocal spatial filter, followed by a spectral filter and photodetector. The gel is placed on a computer-controlled scan stage, and the scanned image of the gel fluorescence is stored and analyzed in a computer. This scanner has been used to detect DNA separated on sequencing gels, agarose mapping gels and pulsed field gels. Sanger sequencing gels were run on M13mp18 DNA using a fluoresceinated primer. The 400-microns-thick gels, loaded with 30 fmol of DNA fragments in 3-mm lanes, were scanned at 78-microns resolution. The high resolution of our scanner coupled with image processing allows us to read up to approximately 300 bases in four adjacent sequencing lanes. The minimum band size that could be detected and read was approximately 200 microns. This instrument has a limiting detection sensitivity of approximately 10 amol of fluorescein-labeled DNA in a 1 x 3-mm band. In applications to agarose mapping gels, we have exploited the fact that DNA can be prestained with ethidium homodimer, followed by electrophoresis and fluorescence detection to achieve picogram sensitivity. We have also developed methods using both ethidium homodimer and thiazole orange staining which permit two-color detection of DNA in one lane.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Resonant secondary light emission from plasmonic Au nanostructures at high electron temperatures created by pulsed-laser excitation

    PubMed Central

    Huang, Jingyu; Wang, Wei; Murphy, Catherine J.; Cahill, David G.

    2014-01-01

    Plasmonic nanostructures are of great current interest as chemical sensors, in vivo imaging agents, and for photothermal therapeutics. We study continuous-wave (cw) and pulsed-laser excitation of aqueous suspensions of Au nanorods as a model system for secondary light emission from plasmonic nanostructures. Resonant secondary emission contributes significantly to the background commonly observed in surface-enhanced Raman scattering and to the light emission generated by pulsed-laser excitation of metallic nanostructures that is often attributed to two-photon luminescence. Spectra collected using cw laser excitation at 488 nm show an enhancement of the broad spectrum of emission at the electromagnetic plasmon resonance of the nanorods. The intensity of anti-Stokes emission collected using cw laser excitation at 785 nm is described by a 300 K thermal distribution of excitations. Excitation by subpicosecond laser pulses at 785 nm broadens and increases the intensity of the anti-Stokes emission in a manner that is consistent with electronic Raman scattering by a high-temperature distribution of electronic excitations predicted by a two-temperature model. Broadening of the pulse duration using an etalon reduces the intensity of anti-Stokes emission in quantitative agreement with the model. Experiments using a pair of subpicosecond optical pulses separated by a variable delay show that the timescale of resonant secondary emission is comparable to the timescale for equilibration of electrons and phonons. PMID:24395798

  13. Piezoelectric Shunt Vibration Damping of F-15 Panel under High Acoustic Excitation

    NASA Technical Reports Server (NTRS)

    Wu, Shu-Yau; Turner, Travis L.; Rizzi, Stephen A.

    2000-01-01

    At last year's SPIE symposium, we reported results of an experiment on structural vibration damping of an F-15 underbelly panel using piezoelectric shunting with five bonded PZT transducers. The panel vibration was induced with an acoustic speaker at an overall sound pressure level (OASPL) of about 90 dB. Amplitude reductions of 13.45 and 10.72 dB were achieved for the first and second modes, respectively, using single- and multiple-mode shunting. It is the purpose of this investigation to extend the passive piezoelectric shunt-damping technique to control structural vibration induced at higher acoustic excitation levels, and to examine the controllability and survivability of the bonded PZT transducers at these high levels. The shunting experiment was performed with the Thermal Acoustic Fatigue Apparatus (TAFA) at the NASA Langley Research Center using the same F-15 underbelly panel. The TAFA is a progressive wave tube facility. The panel was mounted in one wall of the TAFA test section using a specially designed mounting fixture such that the panel was subjected to grazing-incidence acoustic excitation. Five PZT transducers were used with two shunt circuits designed to control the first and second modes of the structure between 200 and 400 Hz. We first determined the values of the shunt inductance and resistance at an OASPL of 130 dB. These values were maintained while we gradually increased the OASPL from 130 to 154 dB in 6-dB steps. During each increment, the frequency response function between accelerometers on the panel and the acoustic excitation measured by microphones, before and after shunting, were recorded. Good response reduction was observed up to the 148dB level. The experiment was stopped at 154 dB due to wire breakage from vibration at a transducer wire joint. The PZT transducers, however, were still bonded well on the panel and survived at this high dB level. We also observed shifting of the frequency peaks toward lower frequency when the OASPL

  14. Compound-Nucleus Formation Following Direct Interactions to Highly-Excited Final States

    SciTech Connect

    Dietrich, F S

    2008-02-05

    When direct reactions populate highly excited, unbound configurations in the residual nucleus, the nucleus may further evolve into a compound nucleus. Alternatively, the residual system may decay by emitting particles into the continuum. Understanding the relative weights of these two processes as a function of the angular momentum and parity deposited in the nucleus is important for the surrogate-reaction technique. A particularly interesting case is compound-nucleus formation via the (d, p) reaction, which may be a useful tool for forming compound nuclei off the valley of stability in inverse-kinematics experiments. We present here a study of the compound formation probability for a closely-related direct reaction, direct-semidirect radiative neutron capture.

  15. Selective excitation of high-Q resonant modes in a bottle/quasi-cylindrical microresonator

    NASA Astrophysics Data System (ADS)

    Dong, Yongchao; Jin, Xueying; Wang, Keyi

    2016-08-01

    We fabricate a bottle/quasi-cylindrical microresonator by using a fusion splicer. This method does not require a real-time control of the translation stages and can easily fabricate a resonator with expected size and shape. Selective excitation of whispering gallery modes (WGMs) in the resonator is realized with a fiber taper coupled at various positions of the resonator along the bottle axis. Most importantly, we obtain a clean and regular spectrum with very high quality factor (Q) modes up to 3.1×107 in the quasi-cylindrical region of the resonator. Moreover, we package the coupling system into a whole device that can be moved freely. The vibration performance tests of the packaged device show that the coupling system with the taper coupled at the quasi-cylindrical region has a remarkable anti-vibration ability. The portability and robustness of the device make it attractive in practical applications.

  16. Cooling by spontaneous decay of highly excited antihydrogen atoms in magnetic traps.

    PubMed

    Pohl, T; Sadeghpour, H R; Nagata, Y; Yamazaki, Y

    2006-11-24

    An efficient cooling mechanism of magnetically trapped, highly excited antihydrogen (H) atoms is presented. This cooling, in addition to the expected evaporative cooling, results in trapping of a large number of H atoms in the ground state. It is found that the final fraction of trapped atoms is insensitive to the initial distribution of H magnetic quantum numbers. Expressions are derived for the cooling efficiency, demonstrating that magnetic quadrupole (cusp) traps provide stronger cooling than higher order magnetic multipoles. The final temperature of H confined in a cusp trap is shown to depend as approximately 2.2T(n0)n(0)(-2/3) on the initial Rydberg level n0 and temperature T(n0).

  17. Cooling by Spontaneous Decay of Highly Excited Antihydrogen Atoms in Magnetic Traps

    SciTech Connect

    Pohl, T.; Sadeghpour, H. R.; Nagata, Y.; Yamazaki, Y.

    2006-11-24

    An efficient cooling mechanism of magnetically trapped, highly excited antihydrogen (H) atoms is presented. This cooling, in addition to the expected evaporative cooling, results in trapping of a large number of H atoms in the ground state. It is found that the final fraction of trapped atoms is insensitive to the initial distribution of H magnetic quantum numbers. Expressions are derived for the cooling efficiency, demonstrating that magnetic quadrupole (cusp) traps provide stronger cooling than higher order magnetic multipoles. The final temperature of H confined in a cusp trap is shown to depend as {approx}2.2T{sub n{sub 0}}n{sub 0}{sup -2/3} on the initial Rydberg level n{sub 0} and temperature T{sub n{sub 0}}.

  18. Deformation increase of high-spin core-excited isomers in the astatine nuclei

    SciTech Connect

    Scheveneels, G.; Hardeman, F.; Neyens, G.; Coussement, R. )

    1991-06-01

    Quadrupole moments of six high-spin isomers in the At isotopes have been measured with the level-mixing-spectroscopy method: {sup 208}At(16{sup {minus}}), {sup 209}At(29/2{sup +}), {sup 210}At(19{sup +},15{sup {minus}}), {sup 211}At(39/2{sup {minus}},29/2{sup +}). The results show that level mixing spectroscopy is a promising technique to determine quadrupole moments of isomers that are difficult to measure by other in-beam hyperfine interaction methods. A large increase of the quadrupole moment is observed if neutrons are excited across or removed from the {ital N}=126 shell closure. This behavior is explained in terms of an enhanced core softness for fewer core neutrons; the aligned valence particles, moving in equatorial orbits, then easily polarize the core towards oblate deformation.

  19. Theory and computation of the attosecond dynamics of pairs of electrons excited by high-frequency short light pulses

    SciTech Connect

    Mercouris, Th.; Komninos, Y.; Nicolaides, C.A.

    2004-03-01

    By defining and solving from first principles, using the state-specific expansion approach, a time-dependent pump-probe problem with real atomic states, we show computationally that, if time resolution reaches the attosecond regime, strongly correlated electronic ''motion'' can be probed and can manifest itself in terms of time-dependent mixing of symmetry-adapted configurations. For the system that was chosen in this study, these configurations, the He 2s2p,2p3d, and 3s3p P{sup o1}, whose radials are computed by solving multiconfigurational Hartree-Fock equations, label doubly excited states (DES) of He inside the 1s{epsilon}p P{sup o1} scattering continuum and act as nonstationary states that mix, and simultaneously decay exponentially to 1s{epsilon}p P{sup o1} via the atomic Hamiltonian, H{sub A}. The herein presented theory and analysis permitted the computation of attosecond snapshots of pairs of electrons in terms of time-dependent probability distributions of the angle between the position vectors of the two electrons. The physical processes were determined by solving ab initio the time-dependent Schroedinger equation, using as initial states either the He 1s{sup 2} or the 1s2s S{sup 1} discrete states and two femtosecond Gaussian pulses of 86 fs full width at half-maximum, having frequencies in resonance with the energies of the correlated states represented by the 2s2p and 2p3d configurations. We calculated the probability of photoabsorption and of two-photon resonance ionization and of the simultaneous oscillatory mixing of the configurations 2s2p,2p3d,3s3p, and 1s{epsilon}p P{sup o1}, within the attosecond scale, via the interactions present in H{sub A}. Among the possible channels for observing the attosecond oscillations of the occupation probabilities of the DES, is the de-excitation path of the transition to the He 1s3d D{sup 1} discrete state, which emits at 6680 A.

  20. Time-resolved doubly bent crystal x-ray spectrometer

    SciTech Connect

    Hockaday, M.P.; Wilke, M.D.; Blake, R.L.; Vaninetti, J.; Gray, N.T.; Nedrow, P.T.

    1988-08-01

    X-ray spectroscopy is an essential tool in high-temperature plasma research. We describe a time-resolved x-ray spectrometer suitable for measuring spectra in harsh environments common to many very high-energy density laboratory plasma sources. The spectrometer consisted of a doubly curved Si(111) crystal diffraction element, a WL-1201 (ZnO:Ga) phosphor, a coherent fiber-optic array, and two visible streak cameras. The spectrometer design described here has a minimum time resolution of 1.3 ns with 2.8-eV spectral resolution over a 200-eV-wide bandpass in the 6--7-keV region of the spectrum. Complete system spectral throughput calibrations were done at the Cornell High Energy Synchrotron (CHESS). Details of the design and calibration results are presented.

  1. Time-resolved doubly bent crystal x-ray spectrometer

    SciTech Connect

    Hockaday, M.P.; Wilke, M.D.; Blake, R.L.; Vaninetti, J.; Gray, N.T.; Nedrow, P.T.

    1988-01-01

    X-ray spectroscopy is an essential tool in high temperature plasma research. We describe a time-resolved x-ray spectrometer suitable for measuring spectra in harsh environments common to many very high energy density laboratory plasma sources. The spectrometer consisted of a doubly curved Si(111) crystal diffraction element, a WL-1201 (ZnO:Ga) phosphor, a coherent fiber optic array, and two visible streak cameras. The spectrometer design described here has a minimum time resolution of 1.3 ns with 2.8 eV spectral resolution over a 200 eV wide bandpass in the 6-7 keV region of the spectrum. Complete system spectral throughput calibrations were done at the Cornell High Energy Synchrotron (CHESS). Details of the design and calibration results are presented. 5 refs., 5 figs.

  2. [Spatial distribution of electrons with high energy in atmospheric pressure glow discharge excited by DC voltage].

    PubMed

    Liu, Zhi-qiang; Jia, Peng-ying; Liu, Tie

    2013-09-01

    Atmospheric pressure glow discharge excited by a DC voltage was realized in a 6 mm air gap by using a needle-water electrode discharge device. The atompheric pressure glow discharge has characteristic regions such as a cathode fall, a negative glow, a Faraday dark space, a positive column and an anode glow. The discharge is a normal glow through analyzing its voltage-current curve. The emission intensity of 337.1 nm spectral line from the second positive system of N2 was investigated because it can indicate the electron density with high energy. Results show that the maxima of high energy electrons appears in the vicinity of the needle tip, and it almost remains constant at other locations. The density of high energy electrons decreases with increasing the voltage. Similarly, it decreases with increasing the value of the ballast resistor. Oxygen atom is important for the sterilization and disinfection. The distribution of oxygen atom was also investigated by optical emission spectroscopy. It was found that the oxygen distribution is similar with the distribution of high energy electrons. These results are important for the application of atmospheric pressure glow discharge in environmental protection and biological treatment. PMID:24369623

  3. Ag-SiO2-Er2O3 Nanocomposites: Highly Effective Upconversion Luminescence at High Power Excitation and High Temperature

    NASA Astrophysics Data System (ADS)

    Xu, Wen; Min, Xiaolei; Chen, Xu; Zhu, Yongsheng; Zhou, Pingwei; Cui, Shaobo; Xu, Sai; Tao, Li; Song, Hongwei

    2014-05-01

    Rare Earth (RE) activated upconversion phosphors (UCPs), have demonstrated significant application potentials in some front fields, including solar energy conversion and bio-application. However, some bottleneck problems should be overcame, such as the lower upconversion efficiency, narrower excitation band, concentration-quenching and temperature-quenching. To solve these problems, the Ag-SiO2-Er2O3 nanocomposites were fabricated, in which the upconversion luminescence (UCL) of Er2O3 was white broadband. Through the interaction of Er2O3 with surface plasmon (SP) of silver nanoparticles (SNPs), the threshold power for generating broadbands was suppressed largely in contrast to the Er2O3 nanoparticles (NPs), while the UCL brightness was enhanced remarkably, ranging from several to 104 times, which strongly depended on the power density of excitation light. At excitation power density of 1.50 W/mm2 of 980 nm light, the UCL intensity of Ag-SiO2-Er2O3 is 40-folds than the well-known NaYF4:Yb3+,Er3+ commercial powders. And more, it is also interesting to observe that the composites demonstrate two excitation bands extending of 780-980 nm, highly improved UCL with elevated temperature and excitation power density. The UCL mechanism related to UCL enhancement was carefully studied.

  4. Substituent and Solvent Effects on Excited State Charge Transfer Behavior of Highly Fluorescent Dyes Containing Thiophenylimidazole-Based Aldehydes

    NASA Technical Reports Server (NTRS)

    Santos, Javier; Bu, Xiu R.; Mintz, Eric A.

    2001-01-01

    The excited state charge transfer for a series of highly fluorescent dyes containing thiophenylimidazole moiety was investigated. These systems follow the Twisted Intramolecular Charge Transfer (TICT) model. Dual fluorescence was observed for each substituted dye. X-ray structures analysis reveals a twisted ground state geometry for the donor substituted aryl on the 4 and 5 position at the imidazole ring. The excited state charge transfer was modeled by a linear solvation energy relationship using Taft's pi and Dimroth's E(sub T)(30) as solvent parameters. There is linear relation between the energy of the fluorescence transition and solvent polarity. The degree of stabilization of the excited state charge transfer was found to be consistent with the intramolecular molecular charge transfer. Excited dipole moment was studied by utilizing the solvatochromic shift method.

  5. Highly Excited H2 in Herbig-Haro 7: Formation Pumping in Shocked Molecular Gas?

    NASA Astrophysics Data System (ADS)

    Pike, R. E.; Geballe, T. R.; Burton, M. G.; Chrysostomou, A.

    2016-05-01

    We have obtained K-band spectra at R ˜ 5000 and an angular resolution of 0.″3 of a section of the Herbig-Haro 7 (HH7) bow shock, using the Near-Infrared Integral Field Spectrograph at Gemini North. Present in the portion of the data cube corresponding to the brightest part of the bow shock are emission lines of H2 with upper state energies ranging from ˜6000 K to the dissociation energy of H2, ˜50,000 K. Because of low signal-to-noise ratios, the highest excitation lines cannot be easily seen elsewhere in the observed region. However, excitation temperatures, measured throughout much of the observed region using lines from levels as high as 25,000 K, are a strong function of upper level energy, indicating that the very highest levels are populated throughout. The level populations in the brightest region are well fit by a two-temperature model, with 98.5% of the emitting gas at T = 1800 K and 1.5% at T = 5200 K. The bulk of the H2 line emission in HH7, from the 1800 K gas, has previously been well-modeled by a continuous shock, but the 5200 K cozmponent is inconsistent with standalone standard continuous shock models. We discuss various possible origins for the hot component and suggest that this component is H2 newly reformed on dust grains and then ejected from them, presumably following dissociation of some of the H2 by the shock.

  6. Obtaining Highly Excited Eigenstates of Many-Body Localized Hamiltonians by the Density Matrix Renormalization Group Approach.

    PubMed

    Khemani, Vedika; Pollmann, Frank; Sondhi, S L

    2016-06-17

    The eigenstates of many-body localized (MBL) Hamiltonians exhibit low entanglement. We adapt the highly successful density-matrix renormalization group method, which is usually used to find modestly entangled ground states of local Hamiltonians, to find individual highly excited eigenstates of MBL Hamiltonians. The adaptation builds on the distinctive spatial structure of such eigenstates. We benchmark our method against the well-studied random field Heisenberg model in one dimension. At moderate to large disorder, the method successfully obtains excited eigenstates with high accuracy, thereby enabling a study of MBL systems at much larger system sizes than those accessible to exact-diagonalization methods. PMID:27367405

  7. Lifetime measurements using the CLARA-PRISMA setup around the {sup 48}Ca doubly-magic nucleus

    SciTech Connect

    Valiente-Dobon, J. J.; Gadea, A.; Stefanini, A. M.; Corradi, L.; De Angelis, G.; Fioretto, E.; Grodner, E.; Mason, P.; Napoli, D. R.; Recchia, F.; Sahin, E.; Mengoni, D.; Farnea, E.; Bazzacco, D.; Montagnoli, G.; Ur, C. A.; Lenzi, S. M.; Lunardi, S.; Scarlassara, F.; Dewald, A.

    2008-11-11

    The lifetimes of the first excited states of nuclei around the doubly-magic nucleus {sup 48}Ca have been determined using a novel method that combines the Recoil Distance Doppler Shift (RDDS) method with the CLARA-PRISMA spectrometers. This is the first time such a method is applied to measure lifetimes of neutron-rich nuclei populated via a multinucleon transfer reaction. This novel method and some preliminary results on lifetimes are presented.

  8. Doubly hybrid density functional for accurate descriptions of nonbond interactions, thermochemistry, and thermochemical kinetics

    PubMed Central

    Zhang, Ying; Xu, Xin; Goddard, William A.

    2009-01-01

    We develop and validate a density functional, XYG3, based on the adiabatic connection formalism and the Görling–Levy coupling-constant perturbation expansion to the second order (PT2). XYG3 is a doubly hybrid functional, containing 3 mixing parameters. It has a nonlocal orbital-dependent component in the exchange term (exact exchange) plus information about the unoccupied Kohn–Sham orbitals in the correlation part (PT2 double excitation). XYG3 is remarkably accurate for thermochemistry, reaction barrier heights, and nonbond interactions of main group molecules. In addition, the accuracy remains nearly constant with system size. PMID:19276116

  9. Time-dependent Hartree-Fock Study of Octupole Vibrations in doubly magic nuclei

    NASA Astrophysics Data System (ADS)

    Simenel, C.; Buete, J.; Vo-Phuoc, K.

    2016-09-01

    Octupole vibrations are studied in some doubly magic nuclei using the time-dependent Hartree-Fock (TDHF) theory with a Skyrme energy density functional. Through the use of the linear response theory, the energies and transition amplitudes of the low-lying vibrational modes for each of the nuclei were determined. Energies were found to be close to experimental results. However, transition amplitudes, quantified by the deformation parameter β3, are underestimated by TDHF. A comparison with single-particle excitations on the Hartree-Fock ground-state shows that the collective octupole vibrations have their energy lowered due to attractive RPA residual interaction.

  10. RESONANT CAVITY EXCITATION SYSTEM

    DOEpatents

    Baker, W.R.; Kerns, Q.A.; Riedel, J.

    1959-01-13

    An apparatus is presented for exciting a cavity resonator with a minimum of difficulty and, more specifically describes a sub-exciter and an amplifier type pre-exciter for the high-frequency cxcitation of large cavities. Instead of applying full voltage to the main oscillator, a sub-excitation voltage is initially used to establish a base level of oscillation in the cavity. A portion of the cavity encrgy is coupled to the input of the pre-exciter where it is amplified and fed back into the cavity when the pre-exciter is energized. After the voltage in the cavity resonator has reached maximum value under excitation by the pre-exciter, full voltage is applied to the oscillator and the pre-exciter is tunned off. The cavity is then excited to the maximum high voltage value of radio frequency by the oscillator.

  11. Photoelectrolysis of water at high current density - Use of ultraviolet laser excitation

    NASA Technical Reports Server (NTRS)

    Bocarsly, A. B.; Bolts, J. M.; Cummins, P. G.; Wrighton, M. S.

    1977-01-01

    The behavior of TiO2 and SrTiO3 photoanodes in cells for the photoelectrolysis of H2O has been investigated for high-intensity 351-,364-nm excitation from an Ar ion laser. Intensities up to 380 W/sq cm have been used. For TiO2 a small amount of surface decomposition is found after irradiation at high intensity, whereas SrTiO3 undergoes no detectable changes. Current-voltage properties for both electrodes are essentially independent of light intensity up to the level of 380 W/sq cm, and there is little if any change in quantum efficiency for electron flow. Photocurrent densities have been shown to exceed 5 A/sq cm for O2 evolution. Data show that the energy storage rate associated with the SrTiO3 photoelectrolysis can exceed 30 W/sq cm; this represents the highest demonstrated rate of sustained optical-to-chemical energy conversion.

  12. Characterization of the multifragment decay channel in highly excited nuclei. [Indiana Univ. , Bloomington, Indiana

    SciTech Connect

    de Souza, R.T.

    1992-10-01

    Characteristics of multifragment decay in heavy-ion induced reactions at intermediate energies are explored. Evolution of the timescale for emission of intermediate mass fragments (IMF: 3[le]Z[le]20) is investigated. Fragments associated with central collisions in the reactions [sup 36]Ar + [sup 197]Au at E/A = 50, 80, and 110 MeV are emitted on an extremely fast timescale, [tau] [le] 75 fm/c, comparable to the transit time of the projectile past the target nucleus. With increasing incident energy, mean fragment emission times decrease, consistent with statistical decay from highly excited systems or fast dynamical processes. To examine the importance of expansion effects in multifragmentation, the transverse kinetic energy of fragments was investigated. Evidence for expansion effects in the system [sup 36]Ar + [sup 197]Au at E/A = 50, 80, and 110 MeV was indicated by the charge dependence of the mean isotropic kinetic energy. At the highest incident energy the data suggest the onset of volume emission. Construction and performance of low-threshold high-resolution detector telescopes is discussed. Three-body Coulomb trajectory calculations are being used to probe kinematical correlations associated with neck emission of IMFs during fission. Initial design and testing of position sensitive parallel plate avalanche counters for upcoming ternary fission experiments is discussed.

  13. Development of High-Throughput Liquid Treatment System using Slot Antenna Excited Microwave Plasma

    NASA Astrophysics Data System (ADS)

    Takitou, Sho; Ito, Michiko; Takashima, Seigou; Nomura, Norio; Kitagawa, Tominori; Toyoda, Hirotaka

    2015-09-01

    Recently, much attention has been given to plasma production under liquid and its industrial applications as well as investigation of chemical reactions as a result of plasma-liquid interactions. In various kinds of plasma production techniques, we have proposed pulsed microwave excited plasma using slot antenna, where damage to the slot electrode can be minimized and plasma volume can be increased. Furthermore, we have proposed an in-line microwave plasma system where plasma is efficiently produced under reduced pressures using Venturi effect, and have demonstrated enhancement of organic decomposition efficiency. For practical use of the plasma liquid treatment, however, cost-effective and more efficient treatment system with high treatment capability is required. In this study, we propose further enhancement of the treatment speed by designing four-parallel-type liquid treatment device where four discharges for the treatment are performed using one microwave power source. Decomposition speed of newly-developed plasma system is investigated. Not only high decomposition rate but also enhanced energy efficiency is realized.

  14. Temperatures, barriers, and level densities of highly excited nuclei with A ~ 160

    NASA Astrophysics Data System (ADS)

    Nebbia, G.; Hagel, K.; Fabris, D.; Majka, Z.; Natowitz, J. B.; Schmitt, R. P.; Sterling, B.; Mouchaty, G.; Berkowitz, G.; Strozewski, K.; Viesti, G.; Gonthier, P. L.; Wilkins, B.; Namboodiri, M. N.; Ho, H.

    1986-08-01

    From coincidence measurements between heavy residues, light particles, and γ-rays, the excitation excitation energy dependence of the temperatures, barriers, and nuclear level density parameters for nuclei with A ~ 160 has been determined. The temperature increases with excitation energy in the range of 100 to 400 MeV consistently with a nuclear level density parameter a increasing from essentially a=A/8 to a=A/13. The emission barrier is lower than predicted by either spin dependent or temperature dependent theoretical calculations. Present address: Ober St. Leonhard-Strasse 8, D-7770 Überlingen, Fed. Rep. Germany.

  15. Electronic noise in high electron-mobility transistors under photo-excitation conditions

    SciTech Connect

    Marinchio, H.; Sabatini, G.; Varani, L.; Palermo, C.; Shiktorov, P.; Starikov, E.; Gruzinskis, V.; Ziade, P.; Kallassy, Z.

    2009-04-23

    The hydrodynamic approach based on the carrier concentration and velocity conservation equations is used to investigate the influence of photo-excitation of plasma waves at the beating frequency of two lasers on the intrinsic extra noise in InGaAs HEMTs caused by thermally-induced plasma oscillations. It is found that, by increasing the amplitude of the photo-excitation, a significant supression of the intrinsic excess noise is observed at the beating frequency as well as at all the frequencies where plasma waves can be excited.

  16. Near yrast states in doubly odd [sup 214]Fr

    SciTech Connect

    Debray, M.E.; Kreiner, A.J.; Kesque, J.M.; Ozafran, M.; Romo, A.; Somacal, H.; Vazquez, M.E. ); Davidson, J.; Davidson, M. ); Ahn, K.; Fossan, D.B.; Liang, Y.; Ma, R.; Paul, E.S.; Piel, W.F. Jr.; Xu, N. )

    1993-11-01

    High spin states of doubly odd [sup 214]Fr[sub 127] have been investigated using in-beam [gamma]-ray and conversion electron spectroscopy techniques through the [sup 206]Pb([sup 11]B, 3[ital n]) and [sup 208]Pb([sup 11]B, 5[ital n]) fusion-evaporation reactions. Completely new spectrocopic information has been obtained. The yrast level structure is established up to spin (19[sup +]) and some information on [gamma] transitions from higher-lying levels is also obtained. Two new isomers [ital T][sub 1/2]=174(20) ns and [ital T][sub 1/2]=11(2) ns were found. Configuration assignments for the low-lying levels are discussed. Information on residual proton-neutron interactions is extracted.

  17. Excitation, propagation and damping of helicon waves in a high density, low temperature plasma

    NASA Astrophysics Data System (ADS)

    Caneses, J. F.; Blackwell, B. D.

    2015-11-01

    The MAGnetized Plasma Interaction Experiment (MAGPIE) is a helicon linear plasma device built to study fusion relevant plasma-surface interactions. In this work, we investigate helicon wave propagation in high density (1018-1019 m-3) low temperature (2-4 eV) magnetized (50-200 G) hydrogen plasma produced by a half-helical antenna operated at 7 MHz and 20 kW. Using the cold dielectric tensor with collisional terms (electron-neutral and Coulomb), helicon wave damping is calculated along the length of MAGPIE using a WKB approximation. Comparison with experiment indicates that wave damping, under these conditions, is entirely collisional. Numerical results from a fully electromagnetic wave code and 2D wavefield measurements indicate that helicon waves are excited at the plasma edge by the antenna's transverse current straps while the helical straps play a secondary role. These waves propagate towards the center of the discharge along the whistler wave ray direction (19 degrees to the background magnetic field), interfere on-axis and form the axial interference pattern commonly observed in helicon devices.

  18. De-Excitation of High-Rydberg Antihydrogen in a Strongly Magnetized Pure Positron Plasma

    NASA Astrophysics Data System (ADS)

    Bass, E. M.

    2005-10-01

    The rate at which highly excited atoms relax to deeper binding is found with classical theories and simulations. This rate relates to antihydrogen formation experiments where such atoms are formed in pure-positron, Penning trap plasmas.ootnotetextG.Gabrielse, N.S. Bowden, P. Oxley, et al., Phys. Rev. Lett. 89, 213401 (2002); M. Amoretti, C. Amsler, G. Bonomi, et al., Nature (London) 419, 456 (2002). The analysis concerns atoms that have passed the kinetic bottleneck at binding energy ɛ 4kT.ootnotetextM.E. Glinsky and T.M. O'Neil, Phys. Fluids B 3, 1279 (1991). Energy loss caused by collisions between atoms and plasma positrons is calculated in two ways: For close collisions, a molecular dynamics simulation gives the energy loss; for large-impact parameter collisions, theoretical expressions based on Fokker-Planck theory are employed.ootnotetextEric M. Bass and Daniel H.E. Dubin, Phys. Plasmas 11, 1240 (2004). For a finite magnetic field, the energy loss rate scales as 1/ɛ, just as for infinite field,^2 but with a larger coefficient. A statistical description of energy loss by radiation and Stark mixing will also be discussed.

  19. KOI-54: THE KEPLER DISCOVERY OF TIDALLY EXCITED PULSATIONS AND BRIGHTENINGS IN A HIGHLY ECCENTRIC BINARY

    SciTech Connect

    Welsh, William F.; Orosz, Jerome A.; Aerts, Conny; Zima, Wolfgang; Brown, Timothy M.; Brugamyer, Erik; Cochran, William D.; Gilliland, Ronald L.; Guzik, Joyce Ann; Kurtz, D. W.; Latham, David W.; Quinn, Samuel N.; Marcy, Geoffrey W.; Allen, Christopher; Bryson, Steve; Caldwell, Douglas A.; Howell, Steve B.; Gautier, Thomas N.

    2011-11-01

    Kepler observations of the star HD 187091 (KIC 8112039, hereafter KOI-54) revealed a remarkable light curve exhibiting sharp periodic brightening events every 41.8 days with a superimposed set of oscillations forming a beating pattern in phase with the brightenings. Spectroscopic observations revealed that this is a binary star with a highly eccentric orbit, e = 0.83. We are able to match the Kepler light curve and radial velocities with a nearly face-on (i = 5.{sup 0}5) binary star model in which the brightening events are caused by tidal distortion and irradiation of nearly identical A stars during their close periastron passage. The two dominant oscillations in the light curve, responsible for the beating pattern, have frequencies that are the 91st and 90th harmonic of the orbital frequency. The power spectrum of the light curve, after removing the binary star brightening component, reveals a large number of pulsations, 30 of which have a signal-to-noise ratio {approx}>7. Nearly all of these pulsations have frequencies that are either integer multiples of the orbital frequency or are tidally split multiples of the orbital frequency. This pattern of frequencies unambiguously establishes the pulsations as resonances between the dynamic tides at periastron and the free oscillation modes of one or both of the stars. KOI-54 is only the fourth star to show such a phenomenon and is by far the richest in terms of excited modes.

  20. Excitation of atoms and molecules in collisions with highly charged ions

    SciTech Connect

    Watson, R.L.

    1992-03-01

    This report discusses research of multicharged nitrogen, oxygen and carbon monoxide molecular ions produced with collision with multicharged argon ions. Properties like ionization, dissociation, and excitation are investigated. (LSP)

  1. High-spin isomers in 212Rn in the region of triple neutron core-excitations

    NASA Astrophysics Data System (ADS)

    Dracoulis, G. D.; Lane, G. J.; Byrne, A. P.; Davidson, P. M.; Kibédi, T.; Nieminen, P.; Watanabe, H.; Wilson, A. N.

    2008-04-01

    The level scheme of 212Rn has been extended to spins of ∼ 38 ℏ and excitation energies of about 13 MeV using the 204Hg(13C, 5n)212Rn reaction and γ-ray spectroscopy. Time correlated techniques have been used to obtain sensitivity to weak transitions and channel selectivity. The excitation energy of the 22+ core-excited isomer has been established at 6174 keV. Two isomers with τ = 25 (2) ns and τ = 12 (2) ns are identified at 12211 and 12548 keV, respectively. These are the highest-spin nuclear isomers now known, and are attributed to configurations involving triple neutron core-excitations coupled to the aligned valence protons. Semi-empirical shell-model calculations can account for most states observed, but with significant energy discrepancies for some configurations.

  2. Electronic excitation and isentropic coefficients of high temperature planetary atmosphere plasmas

    SciTech Connect

    Colonna, Gianpiero; Capitelli, Mario

    2012-07-15

    In this paper, we have discussed the effects of electronically excited states of atomic species in affecting the isentropic coefficients of plasmas, focusing on mixtures representing the atmospheres of Jupiter, Mars, and Earth. General behaviors have been rationalized on the basis of simplified approaches. The contribution of the electronically excited states has been evidenced by comparing results obtained considering only the ground state and those obtained using either Fermi or Griem cutoff criteria.

  3. Nuclear photonics at ultra-high counting rates and higher multipole excitations

    NASA Astrophysics Data System (ADS)

    Thirolf, P. G.; Habs, D.; Filipescu, D.; Gernhäuser, R.; Günther, M. M.; Jentschel, M.; Marginean, N.; Pietralla, N.

    2012-07-01

    Next-generation γ beams from laser Compton-backscattering facilities like ELI-NP (Bucharest)] or MEGa-Ray (Livermore) will drastically exceed the photon flux presently available at existing facilities, reaching or even exceeding 1013 γ/sec. The beam structure as presently foreseen for MEGa-Ray and ELI-NP builds upon a structure of macro-pulses (˜120 Hz) for the electron beam, accelerated with X-band technology at 11.5 GHz, resulting in a micro structure of 87 ps distance between the electron pulses acting as mirrors for a counterpropagating intense laser. In total each 8.3 ms a γ pulse series with a duration of about 100 ns will impinge on the target, resulting in an instantaneous photon flux of about 1018 γ/s, thus introducing major challenges in view of pile-up. Novel γ optics will be applied to monochromatize the γ beam to ultimately ΔE/E˜10-6. Thus level-selective spectroscopy of higher multipole excitations will become accessible with good contrast for the first time. Fast responding γ detectors, e.g. based on advanced scintillator technology (e.g. LaBr3(Ce)) allow for measurements with count rates as high as 106-107 γ/s without significant drop of performance. Data handling adapted to the beam conditions could be performed by fast digitizing electronics, able to sample data traces during the micro-pulse duration, while the subsequent macro-pulse gap of ca. 8 ms leaves ample time for data readout. A ball of LaBr3 detectors with digital readout appears to best suited for this novel type of nuclear photonics at ultra-high counting rates.

  4. Nuclear photonics at ultra-high counting rates and higher multipole excitations

    SciTech Connect

    Thirolf, P. G.; Habs, D.; Filipescu, D.; Gernhaeuser, R.; Guenther, M. M.; Jentschel, M.; Marginean, N.; Pietralla, N.

    2012-07-09

    Next-generation {gamma} beams from laser Compton-backscattering facilities like ELI-NP (Bucharest)] or MEGa-Ray (Livermore) will drastically exceed the photon flux presently available at existing facilities, reaching or even exceeding 10{sup 13}{gamma}/sec. The beam structure as presently foreseen for MEGa-Ray and ELI-NP builds upon a structure of macro-pulses ({approx}120 Hz) for the electron beam, accelerated with X-band technology at 11.5 GHz, resulting in a micro structure of 87 ps distance between the electron pulses acting as mirrors for a counterpropagating intense laser. In total each 8.3 ms a {gamma} pulse series with a duration of about 100 ns will impinge on the target, resulting in an instantaneous photon flux of about 10{sup 18}{gamma}/s, thus introducing major challenges in view of pile-up. Novel {gamma} optics will be applied to monochromatize the {gamma} beam to ultimately {Delta}E/E{approx}10{sup -6}. Thus level-selective spectroscopy of higher multipole excitations will become accessible with good contrast for the first time. Fast responding {gamma} detectors, e.g. based on advanced scintillator technology (e.g. LaBr{sub 3}(Ce)) allow for measurements with count rates as high as 10{sup 6}-10{sup 7}{gamma}/s without significant drop of performance. Data handling adapted to the beam conditions could be performed by fast digitizing electronics, able to sample data traces during the micro-pulse duration, while the subsequent macro-pulse gap of ca. 8 ms leaves ample time for data readout. A ball of LaBr{sub 3} detectors with digital readout appears to best suited for this novel type of nuclear photonics at ultra-high counting rates.

  5. The Effects of Natural Hybridization on the Regulation of Doubly Uniparental Mtdna Inheritance in Blue Mussels (Mytilus Spp.)

    PubMed Central

    Rawson, P. D.; Secor, C. L.; Hilbish, T. J.

    1996-01-01

    Blue mussels in the Mytilus edulis species complex have a doubly uniparental mode of mtDNA inheritance with separate maternal and paternal mtDNA lineages. Female mussels inherit their mtDNA solely from their mother, while males inherit mtDNA from both parents. In the male gonad the paternal mtDNA is preferentially replicated so that only paternal mtDNA is transmitted from fathers to sons. Hybridization is common among differentiated blue mussel taxa; whenever it involves M. trossulus, doubly uniparental mtDNA inheritance is disrupted. We have found high frequencies of males without and females with paternal mtDNA among hybrid mussels produced by interspecific matings between M. galloprovincialis and M. trossulus. In contrast, hybridization between M. galloprovincialis and M. edulis does not affect doubly uniparental inheritance, indicating a difference in the divergence of the mechanisms regulating mtDNA inheritance among the three blue mussel taxa. Our data indicate a high frequency of disrupted mtDNA transmission in F(1) hybrids and suggest that two separate mechanisms, one regulating the transmission of paternal mtDNA to males and another inhibiting the establishment of paternal mtDNA in females, act to regulate doubly uniparental inheritance. We propose a model for the regulation of doubly uniparental inheritance that is consistent with these observations. PMID:8878689

  6. A Preliminary Transcranial Magnetic Stimulation Study of Cortical Inhibition and Excitability in High-Functioning Autism and Asperger Disorder

    ERIC Educational Resources Information Center

    Enticott, Peter G.; Rinehart, Nicole J.; Tonge, Bruce J.; Bradshaw, John L.; Fitzgerald, Paul B.

    2010-01-01

    Aim: Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS). Method: Participants were diagnosed by…

  7. High-spin states in the semimagic nucleus 89Y and neutron-core excitations in the N =50 isotones

    NASA Astrophysics Data System (ADS)

    Li, Z. Q.; Wang, S. Y.; Niu, C. Y.; Qi, B.; Wang, S.; Sun, D. P.; Liu, C.; Xu, C. J.; Liu, L.; Zhang, P.; Wu, X. G.; Li, G. S.; He, C. Y.; Zheng, Y.; Li, C. B.; Yu, B. B.; Hu, S. P.; Yao, S. H.; Cao, X. P.; Wang, J. L.

    2016-07-01

    The semimagic nucleus 89Y 89 has been investigated using the 82Se(11>B,4 n ) reaction at beam energies of 48 and 52 MeV. More than 24 new transitions have been identified, leading to a considerable extension of the level structures of 89Y. The experimental results are compared with the large-basis shell model calculations. They show that cross-shell neutron excitations play a pivotal role in high-spin level structures of 89Y. The systematic features of neutron-core excitations in the N =50 isotones are also discussed.

  8. Magnetic excitations and lattice distortions in highly-doped (Sr1-xLax)3 Ir2O7

    NASA Astrophysics Data System (ADS)

    Hogan, Tom; Upton, Mary; Wang, Xiaoping; Wilson, Stephen

    (Sr1-xLa,SUBx)3Ir2O7 has been shown to undergo a first-order phase transition from a localized antiferromagnetic insulating state to a correlated metal. We discuss the further characterization of these correlations by examining the excitation spectra of a highly-doped sample. These reveal evidence of a dispersive feature associated with an over-damped magnon mode, similar to the behavior of the undoped parent compound, as well as a higher energy excitation. The nature of the lattice distortion brought on by La-doping will also be discussed.

  9. Widefield Two-Photon Excitation without Scanning: Live Cell Microscopy with High Time Resolution and Low Photo-Bleaching

    PubMed Central

    Amor, Rumelo; McDonald, Alison; Trägårdh, Johanna; Robb, Gillian; Wilson, Louise; Abdul Rahman, Nor Zaihana; Dempster, John; Amos, William Bradshaw; Bushell, Trevor J.; McConnell, Gail

    2016-01-01

    We demonstrate fluorescence imaging by two-photon excitation without scanning in biological specimens as previously described by Hwang and co-workers, but with an increased field size and with framing rates of up to 100 Hz. During recordings of synaptically-driven Ca2+ events in primary rat hippocampal neurone cultures loaded with the fluorescent Ca2+ indicator Fluo-4 AM, we have observed greatly reduced photo-bleaching in comparison with single-photon excitation. This method, which requires no costly additions to the microscope, promises to be useful for work where high time-resolution is required. PMID:26824845

  10. Widefield Two-Photon Excitation without Scanning: Live Cell Microscopy with High Time Resolution and Low Photo-Bleaching.

    PubMed

    Amor, Rumelo; McDonald, Alison; Trägårdh, Johanna; Robb, Gillian; Wilson, Louise; Abdul Rahman, Nor Zaihana; Dempster, John; Amos, William Bradshaw; Bushell, Trevor J; McConnell, Gail

    2016-01-01

    We demonstrate fluorescence imaging by two-photon excitation without scanning in biological specimens as previously described by Hwang and co-workers, but with an increased field size and with framing rates of up to 100 Hz. During recordings of synaptically-driven Ca(2+) events in primary rat hippocampal neurone cultures loaded with the fluorescent Ca(2+) indicator Fluo-4 AM, we have observed greatly reduced photo-bleaching in comparison with single-photon excitation. This method, which requires no costly additions to the microscope, promises to be useful for work where high time-resolution is required.

  11. Enhanced high-order-harmonic generation and wave mixing via two-color multiphoton excitation of atoms and molecules

    NASA Astrophysics Data System (ADS)

    Avetissian, H. K.; Avchyan, B. R.; Mkrtchian, G. F.

    2016-07-01

    We consider harmonics generation and wave mixing by two-color multiphoton resonant excitation of three-level atoms and molecules in strong laser fields. The coherent part of the spectra corresponding to multicolor harmonics generation is investigated. The obtained analytical results on the basis of a generalized rotating wave approximation are in a good agreement with numerical calculations. The results applied to the hydrogen atoms and homonuclear diatomic molecular ions show that one can achieve efficient generation of moderately high multicolor harmonics via multiphoton resonant excitation by appropriate laser pulses.

  12. Absolute doubly differential bremsstrahlung cross sections from rare gas atoms

    NASA Astrophysics Data System (ADS)

    Portillo, Salvador

    The absolute doubly differential bremsstrahlung cross section has been measured for 28 and 50 keV electrons incident on the rare gases Xe, Kr, Ar and Ne. The cross sections are differential with respect to energy and photon emission. A SiLi solid state detector measured data at 90° with respect to the beam line. A thorough analysis of the experimental systematic error yielded a high degree of confidence in the experimental data. The absolute bremsstrahlung doubly differential cross sections provided for a rigorous test of the normal bremsstrahlung theory, tabulated by Kissel, Quarles and Pratt1 (KQP) and of the SA theory2 that includes the contribution from polarization bremsstrahlung. To test the theories a comparison of the overall magnitude of the cross section as well as comparison of the photon energy dependence was carried out. The KQP theoretical values underestimated the magnitude of the cross section for all targets and for both energies. The SA values were in excellent agreement with the 28 keV data. For the 50keV data the fit was also very good. However, there were energy regions where there was a small discrepancy between the theory and the data. This suggests that the Polarization Bremsstrahlung (PB) mechanism does contribute to the overall spectrum and is detectable in this parameter space. 1Kissel, L., Quarles, C. A., Pratt, R. H., Atom. Data Nucl. Data Tables 28, 381 (1983). 2Avdonina N. B., Pratt, R. H., J. Phys. B: At. Mol. Opt. Phys. 32 4261 (1999).

  13. Search for the doubly charmed baryon

    NASA Astrophysics Data System (ADS)

    Aaij, R.; Adeva, B.; Adinolfi, M.; Adrover, C.; Affolder, A.; Ajaltouni, Z.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; Anderlini, L.; Anderson, J.; Andreassen, R.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Balagura, V.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Bauer, Th.; Bay, A.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Belogurov, S.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bettler, M.-O.; van Beuzekom, M.; Bien, A.; Bifani, S.; Bird, T.; Bizzeti, A.; Bjørnstad, P. M.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borgia, A.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Brambach, T.; van den Brand, J.; Bressieux, J.; Brett, D.; Britsch, M.; Britton, T.; Brook, N. H.; Brown, H.; Bursche, A.; Busetto, G.; Buytaert, J.; Cadeddu, S.; Callot, O.; Calvi, M.; Calvo Gomez, M.; Camboni, A.; Campana, P.; Campora Perez, D.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carranza-Mejia, H.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cenci, R.; Charles, M.; Charpentier, Ph.; Cheung, S.-F.; Chiapolini, N.; Chrzaszcz, M.; Ciba, K.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coca, C.; Coco, V.; Cogan, J.; Cogneras, E.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; David, P.; David, P. N. Y.; Davis, A.; De Bonis, I.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Silva, W.; De Simone, P.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Derkach, D.; Deschamps, O.; Dettori, F.; Di Canto, A.; Dijkstra, H.; Dogaru, M.; Donleavy, S.; Dordei, F.; Dosil Suárez, A.; Dossett, D.; Dovbnya, A.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; van Eijk, D.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Falabella, A.; Färber, C.; Farinelli, C.; Farry, S.; Ferguson, D.; Fernandez Albor, V.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fitzpatrick, C.; Fontana, M.; Fontanelli, F.; Forty, R.; Francisco, O.; Frank, M.; Frei, C.; Frosini, M.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gandelman, M.; Gandini, P.; Gao, Y.; Garofoli, J.; Garosi, P.; Garra Tico, J.; Garrido, L.; Gaspar, C.; Gauld, R.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gibson, V.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gorbounov, P.; Gordon, H.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Hampson, T.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; Hartmann, T.; He, J.; Head, T.; Heijne, V.; Hennessy, K.; Henrard, P.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hicks, E.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Hunt, P.; Huse, T.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Iakovenko, V.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jans, E.; Jaton, P.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Kaballo, M.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Kenyon, I. R.; Ketel, T.; Khanji, B.; Kochebina, O.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Korolev, M.; Kozlinskiy, A.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Kruse, F.; Kucharczyk, M.; Kudryavtsev, V.; Kurek, K.; Kvaratskheliya, T.; La Thi, V. N.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lambert, R. W.; Lanciotti, E.; Lanfranchi, G.; Langenbruch, C.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Leo, S.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Li Gioi, L.; Liles, M.; Lindner, R.; Linn, C.; Liu, B.; Liu, G.; Lohn, S.; Longstaff, I.; Lopes, J. H.; Lopez-March, N.; Lu, H.; Lucchesi, D.; Luisier, J.; Luo, H.; Lupton, O.; Machefert, F.; Machikhiliyan, I. V.; Maciuc, F.; Maev, O.; Malde, S.; Manca, G.; Mancinelli, G.; Maratas, J.; Marconi, U.; Marino, P.; Märki, R.; Marks, J.; Martellotti, G.; Martens, A.; Martín Sánchez, A.; Martinelli, M.; Martinez Santos, D.; Martins Tostes, D.; Martynov, A.; Massafferri, A.; Matev, R.; Mathe, Z.; Matteuzzi, C.; Maurice, E.; Mazurov, A.; McCarthy, J.; McNab, A.; McNulty, R.; McSkelly, B.; Meadows, B.; Meier, F.; Meissner, M.; Merk, M.; Milanes, D. A.; Minard, M.-N.; Molina Rodriguez, J.; Monteil, S.; Moran, D.; Morawski, P.; Mordà, A.; Morello, M. J.; Mountain, R.; Mous, I.; Muheim, F.; Müller, K.; Muresan, R.; Muryn, B.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nasteva, I.; Needham, M.; Neubert, S.; Neufeld, N.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Nicol, M.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Nomerotski, A.; Novoselov, A.; Oblakowska-Mucha, A.; Obraztsov, V.; Oggero, S.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Orlandea, M.; Otalora Goicochea, J. M.; Owen, P.; Oyanguren, A.; Pal, B. K.; Palano, A.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Parkes, C.; Parkinson, C. J.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrick, G. N.; Patrignani, C.; Pavel-Nicorescu, C.; Pazos Alvarez, A.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perez Trigo, E.; Pérez-Calero Yzquierdo, A.; Perret, P.; Perrin-Terrin, M.; Pescatore, L.; Pesen, E.; Pessina, G.; Petridis, K.; Petrolini, A.; Phan, A.; Picatoste Olloqui, E.; Pietrzyk, B.; Pilař, T.; Pinci, D.; Playfer, S.; Plo Casasus, M.; Polci, F.; Polok, G.; Poluektov, A.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Powell, A.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Rachwal, B.; Rademacker, J. H.; Rakotomiaramanana, B.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redford, S.; Reichert, S.; Reid, M. M.; dos Reis, A. C.; Ricciardi, S.; Richards, A.; Rinnert, K.; Rives Molina, V.; Roa Romero, D. A.; Robbe, P.; Roberts, D. A.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Perez, P.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Rotondo, M.; Rouvinet, J.; Ruf, T.; Ruffini, F.; Ruiz, H.; Ruiz Valls, P.; Sabatino, G.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salustino Guimaraes, V.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santovetti, E.; Sapunov, M.; Sarti, A.; Satriano, C.; Satta, A.; Savrie, M.; Savrina, D.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmidt, B.; Schneider, O.; Schopper, A.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Seco, M.; Semennikov, A.; Senderowska, K.; Sepp, I.; Serra, N.; Serrano, J.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, O.; Shevchenko, V.; Shires, A.; Silva Coutinho, R.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, N. A.; Smith, E.; Smith, E.; Smith, J.; Smith, M.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Sparkes, A.; Spradlin, P.; Stagni, F.; Stahl, S.; Steinkamp, O.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Straticiuc, M.; Straumann, U.; Subbiah, V. K.; Sun, L.; Sutcliffe, W.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szczypka, P.; Szilard, D.; Szumlak, T.; T'Jampens, S.; Teklishyn, M.; Teodorescu, E.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Tolk, S.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Tran, M. T.; Tresch, M.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ubeda Garcia, M.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vagnoni, V.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vilasis-Cardona, X.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; Voss, H.; Waldi, R.; Wallace, C.; Wallace, R.; Wandernoth, S.; Wang, J.; Ward, D. R.; Watson, N. K.; Webber, A. D.; Websdale, D.; Whitehead, M.; Wicht, J.; Wiechczynski, J.; Wiedner, D.; Wiggers, L.; Wilkinson, G.; Williams, M. P.; Williams, M.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wright, S.; Wu, S.; Wyllie, K.; Xie, Y.; Xing, Z.; Yang, Z.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, F.; Zhang, L.; Zhang, W. C.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.; Zvyagin, A.

    2013-12-01

    A search for the doubly charmed baryon in the decay mode is performed with a data sample, corresponding to an integrated luminosity of 0.65 fb-1, of pp collisions recorded at a centre-of-mass energy of 7 TeV. No significant signal is found in the mass range 3300-3800 MeV /c 2. Upper limits at the 95% confidence level on the ratio of the production cross-section times branching fraction to that of the , R, are given as a function of the mass and lifetime. The largest upper limits range from R < 1.5 × 10-2 for a lifetime of 100 fs to R < 3 .9 × 10-4 for a lifetime of 400 fs. [Figure not available: see fulltext.

  14. Transient removal of alkaline zones after excitation of Chara cells is associated with inactivation of high conductance in the plasmalemma.

    PubMed

    Bulychev, Alexander A; Krupenina, Natalia A

    2009-08-01

    The action potential (AP) of excitable plant cells is a multifunctional physiological signal. Its generation in characean algae suppresses the pH banding for 15-30 min and enhances the heterogeneity of spatial distribution of photosynthetic activity. This suppression is largely due to the cessation of H(+) influx (OH(-) efflux) in the alkaline cell regions. Measurements of local pH and membrane conductance in individual space-clamped alkaline zones (small cell areas bathed in an isolated pool of external medium) showed that the AP generation is followed by the transient disappearance of alkaline zone in parallel with a large decrease in membrane conductance. These changes, specific to alkaline zones, were only observed under continuous illumination following a relaxation period of at least 15 min after previous excitation. The excitation of dark-adapted cells produced no conductance changes in the post-excitation period. The results indicate that the origin of alkaline zones in characean cells is not due to operation of electroneutral H(+)/HCO(3)(-) symport or OH(-)/HCO(3)(-) antiport. It is concluded that the membrane excitation is associated with inactivation of plasmalemma high conductance in the alkaline cell regions. PMID:19820298

  15. Transient removal of alkaline zones after excitation of Chara cells is associated with inactivation of high conductance in the plasmalemma.

    PubMed

    Bulychev, Alexander A; Krupenina, Natalia A

    2009-08-01

    The action potential (AP) of excitable plant cells is a multifunctional physiological signal. Its generation in characean algae suppresses the pH banding for 15-30 min and enhances the heterogeneity of spatial distribution of photosynthetic activity. This suppression is largely due to the cessation of H(+) influx (OH(-) efflux) in the alkaline cell regions. Measurements of local pH and membrane conductance in individual space-clamped alkaline zones (small cell areas bathed in an isolated pool of external medium) showed that the AP generation is followed by the transient disappearance of alkaline zone in parallel with a large decrease in membrane conductance. These changes, specific to alkaline zones, were only observed under continuous illumination following a relaxation period of at least 15 min after previous excitation. The excitation of dark-adapted cells produced no conductance changes in the post-excitation period. The results indicate that the origin of alkaline zones in characean cells is not due to operation of electroneutral H(+)/HCO(3)(-) symport or OH(-)/HCO(3)(-) antiport. It is concluded that the membrane excitation is associated with inactivation of plasmalemma high conductance in the alkaline cell regions.

  16. One- and two-photon spectroscopy of highly excited states of alkali-metal atoms on helium nanodroplets

    SciTech Connect

    Pifrader, Alexandra; Allard, Olivier; Auboeck, Gerald; Callegari, Carlo; Ernst, Wolfgang E.; Huber, Robert; Ancilotto, Francesco

    2010-10-28

    Alkali-metal atoms captured on the surface of superfluid helium droplets are excited to high energies ({approx_equal}3 eV) by means of pulsed lasers, and their laser-induced-fluorescence spectra are recorded. We report on the one-photon excitation of the (n+1)p(leftarrow)ns transition of K, Rb, and Cs (n=4, 5, and 6, respectively) and on the two-photon one-color excitation of the 5d(leftarrow)5s transition of Rb. Gated-photon-counting measurements are consistent with the relaxation rates of the bare atoms, hence consistent with the reasonable expectation that atoms quickly desorb from the droplet and droplet-induced relaxation need not be invoked.

  17. Decay Out of the Yrast and Excited Highly Deformed Bands in the Even-Even Nucleus {sup 134}Nd

    SciTech Connect

    Petrache, C.M.; Bazzacco, D.; Lunardi, S.; Rossi Alvarez, C.; Venturelli, R.; Pavan, P.; Medina, N.H.; Rao, M.N.; Burch, R.; de Angelis, G.; Gadea, A.; Maron, G.; Napoli, D.R.; Zhu, L.; Wyss, R.

    1996-07-01

    The decay out of the yrast and excited highly deformed (HD) bands in {sup 134}Nd has been investigated via the {sup 28}Si+{sup 110}Pd reaction at 130MeV using the GASP array. Several deexcitation pathways have been established for both the yrast and excited HD bands. The resulting spins remove previous ambiguities in the assignment of the excited HD band and confirm the structure assigned to the yrast HD band. The decay out is understood in terms of mixing between the normal-deformed and HD states, which is triggered by the crossing between the {nu}{ital i}{sub 13/2} and {nu}{ital d}{sub 5/2} orbitals. {copyright} {ital 1996 The American Physical Society.}

  18. Quenching of OH(A(2)Sigma(+)) by H(2) through conical intersections: highly excited products in nonreactive channel.

    PubMed

    Zhang, Pei-Yu; Lu, Rui-Feng; Chu, Tian-Shu; Han, Ke-Li

    2010-06-24

    Nonadiabatic quantum scattering calculations have been carried out for the reactive and nonreactive quenching of OH(A(2)Sigma(+)) in collisions with molecular H(2) on two new potential energy surfaces of the 1A' and 2A' states. Integral cross sections of the reactive and nonreactive quenching channels and the quantum state distributions of the nonreactive channel have been obtained. The theory reveals a high degree of rotational excitation of the quenched OH(X(2)II) products and vibrational excitation of the H(2) products. The calculated results are in good agreement with the existing experimental data. The topography of the potential energy surfaces in the conical intersection regions is provided in order to discuss the origin of the internal excitations of nonreactive products and the branching of the reactive and nonreactive channels.

  19. Nonlinear low frequency water waves in a cylindrical shell subjected to high frequency excitations - Part I: Experimental study

    NASA Astrophysics Data System (ADS)

    Dajun, Wang; Chunyan, Zhou; Li, Junbao; Shen, Song; Li, Min; Liu, Xijun

    2013-07-01

    This paper presents an experimental investigation on nonlinear low frequency gravity water waves in a partially filled cylindrical shell subjected to high frequency horizontal excitations. The characteristics of natural frequencies and mode shapes of the water-shell coupled system are discussed. The boundaries for onset of gravity waves are measured and plotted by curves of critical excitation force magnitude with respect to excitation frequency. For nonlinear water waves, the time history signals and their spectrums of motion on both water surface and shell are recorded. The shapes of water surface are also measured using scanning laser vibrometer. In particular, the phenomenon of transitions between different gravity wave patterns is observed and expressed by the waterfall graphs. These results exhibit pronounced nonlinear properties of shell-fluid coupled system.

  20. Excitable dynamics in high-Lewis number premixed gas combustion at normal and microgravity

    NASA Technical Reports Server (NTRS)

    Pearlman, Howard

    1995-01-01

    Freely-propagating, premixed gas flames in high-Lewis (Le) number, quiescent mixtures are studied experimentally in tubes of various diameter at normal (lg) and microgravity (mu g). A premixture of lean butane and oxygen diluted with helium, argon, neon, nitrogen or a mixture of multiple diluents is examined such that the thermal diffusivity of the mixture (and to a lesser extent, the mass diffusivity of the rate-limiting component) is systematically varied. In effect, different diluents allow variation of the Le without changing the chemistry. The flames are recorded with high speed cinematography and their stability is visually assessed. Different modes of propagation were observed depending on the diameter of the tubes (different conductive heat loss), the composition of the mixture and the g-level. At 1g, four modes of propagation were observed in small and intermediate diameter tubes (large conductive heat loss): (1) steadily propagating flames, (2) radial and longitudinal pulsating flames, (3) 'wavering' flames, and (4) rotating spiral flames. As the diameter of the tube increases, the radial modes become more pronounced while the longitudinal modes systematically disappear. Also, multiple, simultaneous, spatially-separated 'pacemaker' sites are observed in intermediate and large diameter tubes. Each site starts as a small region of high luminosity and develops into a flamelet which assumes the form of one of the fore mentioned modes. These flamelets eventually interact, annihilate each other in their regions of intersection and merge at their newly created free-ends. For very large tubes, radially-propagating wave-trains (believed to be 'trigger waves') are observed. These are analogous to the radial pulsations observed in the smaller diameter tubes. At mu g, three modes of propagation have been observed: (1) steadily propagating flames, (2) radial and longitudinal pulsating flames, and (3) multi-armed, rotating flames. Since the pulsating mode exists at mu

  1. The structure of the high-energy spin excitations in YBa2Cu3O6+x

    NASA Astrophysics Data System (ADS)

    Hayden, Stephen

    2005-03-01

    The most obvious feature in the magnetic excitations of high-Tc superconductors is the so-called `resonance-mode'. This mode is strongly coupled to the superconductivity, however, it has not been found in the La2-x(Ba,Sr)xCuO4 family and is not universally present in Bi2Sr2CaCu2O8+δ. Here we use inelastic neutron scattering to characterize other excitations at higher energies which may be relevant to the superconductive pairing in YBa2Cu3O6.6. We observe a square-shaped continuum of excitations in reciprocal space [1]. These excitations have energies greater than the superconducting pairing energy, are present at Tc, and have spectral weight far exceeding that of the `resonance'. The discovery of similar excitations in La2-xBaxCuO4 [2] suggests that they are a general property of the copper oxides, and a candidate for mediating the electron pairing. Our data show that the high-energy magnetic excitations in the high-temperature superconductor YBa2Cu3O6.6 consists of a continuum of scattering bounded by a square and peaked at wavevector positions Qɛ =(1/2±ɛ,1/2±ɛ) and (1/2±ɛ,1/2ɛ). A similar structure is observed in the high-energy magnetic excitations of the magnetically ordered but weakly superconducting compound La1.85Ba0.125CuO4 [2]. This suggests there is universality, both in the low-energy and the high-energy spin dynamics between two very different classes of high-Tc superconductor. [1] S.M. Hayden, H.A. Mook, P.C. Dai, T.G. Perring, and F. Dogan, Nature 429, 531-534 (2004) [2] J.M. Tranquada, H. Woo, T.G. Perring, H. Goka, G.D. Gu , G. Xu, M. Fujita, K.Yamada K, Nature 429, 534-538 (2004).

  2. Ultrafast Dynamics of 1,3-Cyclohexadiene in Highly Excited States

    DOE PAGESBeta

    Bühler, Christine C.; Minitti, Michael P.; Deb, Sanghamitra; Bao, Jie; Weber, Peter M.

    2011-01-01

    The ultrafast dynamics of 1,3-cyclohexadiene has been investigated via structurally sensitive Rydberg electron binding energies and shown to differ upon excitation to the 1B state and the 3p Rydberg state. Excitation of the molecule with 4.63 eV photons into the ultrashort-lived 1B state yields the well-known ring opening to 1,3,5-hexatriene, while a 5.99 eV photon lifts the molecule directly into the 3p-Rydberg state. Excitation to 3p does not induce ring opening. In both experiments, time-dependent shifts of the Rydberg electron binding energy reflect the structural dynamics of the molecular core. Structural distortions associated with 3p-excitation cause a dynamical shift in the -more » and -binding energies by 10 and 26 meV/ps, respectively, whereas after excitation into 1B, more severe structural transformations along the ring-opening coordinate produce shifts at a rate of 40 to 60 meV/ps. The experiment validates photoionization-photoelectron spectroscopy via Rydberg states as a powerful technique to observe structural dynamics of polyatomic molecules.« less

  3. Doubly Magic Optical Trapping for Cs Atom Hyperfine Clock Transitions

    NASA Astrophysics Data System (ADS)

    Carr, A. W.; Saffman, M.

    2016-10-01

    We analyze doubly magic trapping of Cs hyperfine transitions including previously neglected contributions from the ground state hyperpolarizability and the interaction of the laser light and a static magnetic field. Extensive numerical searches do not reveal any doubly magic trapping conditions for any pair of hyperfine states. However, including the hyperpolarizability reveals light intensity insensitive traps for a wide range of wavelengths at specific intensities. We then investigate the use of bichromatic trapping light fields. Deploying a bichromatic scheme, we demonstrate doubly magic red and blue detuned traps for pairs of states separated by one or two single photon transitions.

  4. Spectroscopy of doubly and triply-charmed baryons from lattice QCD

    SciTech Connect

    Padmanath, M.; Edwards, Robert G.; Mathur, Nilmani; Peardon, Michael

    2013-11-01

    We present the ground and excited state spectra of doubly and triply-charmed baryons by using lattice QCD with dynamical clover fermions. A large set of baryonic operators that respect the symmetries of the lattice and are obtained after subduction from their continuum analogues are utilized. Using novel computational techniques correlation functions of these operators are generated and the variational method is exploited to extract excited states. The lattice spectra that we obtain have baryonic states with well-defined total spins up to 7/2 and the low lying states remarkably resemble the expectations of quantum numbers from SU(6) Ⓧ O(3) symmetry. Various energy splittings between the extracted states, including splittings due to hyperfine as well as spin-orbit coupling, are considered and those are also compared against similar energy splittings at other quark masses. Using those splittings for doubly-charmed baryons, and taking input of experimental Bc meson mass, we predict the mass splittings of B*c-Bc to be about 80 ± 8 MeV and mΩccb=8050±10 MeV.

  5. High-speed automated DNA sequencing utilizing from-the-side laser excitation

    NASA Astrophysics Data System (ADS)

    Westphall, Michael S.; Brumley, Robert L., Jr.; Buxton, Erin C.; Smith, Lloyd M.

    1995-04-01

    The Human Genome Initiative is an ambitious international effort to map and sequence the three billion bases of DNA encoded in the human genome. If successfully completed, the resultant sequence database will be a tool of unparalleled power for biomedical research. One of the major challenges of this project is in the area of DNA sequencing technology. At this time, virtually all DNA sequencing is based upon the separation of DNA fragments in high resolution polyacrylamide gels. This method, as generally practiced, is one to two orders of magnitude too slow and expensive for the successful completion of the Human Genome projection. One reasonable approach is improved sequencing of DNA fragments is to increase the performance of such gel-based sequencing methods. Decreased sequencing times may be obtained by increasing the magnitude of the electric field employed. This is not possible with conventional sequencing, due to the fact that the additional heat associated with the increased electric field cannot be adequately dissipated. Recent developments in the use of thin gels have addressed this problem. Performing electrophoresis in ultrathin (50 to 100 microns) gels greatly increases the heat transfer efficiency, thus allowing the benefits of larger electric fields to be obtained. An increase in separation speed of about an order of magnitude is readily achieved. Thin gels have successfully been used in capillary and slab formats. A detection system has been designed for use with a multiple fluorophore sequencing strategy in horizontal ultrathin slab gels. The system employs laser through-the-side excitation and a cooled CCD detector; this allows for the parallel detection of up to 24 sets of four fluorescently labeled DNA sequencing reactions during their electrophoretic separation in ultrathin (115 micrometers ) denaturing polyacrylamide gels. Four hundred bases of sequence information is obtained from 100 ng of M13 template DNA in an hour, corresponding to an

  6. Effect of electronic excitation on high-temperature flows behind strong shock waves

    SciTech Connect

    Istomin, V. A.; Kustova, E. V.

    2014-12-09

    In the present paper, a strongly non-equilibrium one-dimensional steady-state flow behind the plane shock wave is studied. We consider a high-temperature chemically reacting five-component ionized mixture of nitrogen species (N{sub 2}/N{sub 2}{sup 2}/N/N{sup +}/e{sup −}) taking into account electronic degrees of freedom in N and N{sup +} (170 and 625 electronic energy levels respectively), and electronic-rotational-vibrational modes in N{sub 2} and N{sub 2}{sup +} (5 and 7 electronic terms). Non-equilibrium reactions of ionization, dissociation, recombination and charge-transfer are included to the kinetic scheme. The system of governing equations is written under the assumption that translation and internal energy relaxation is fast whereas chemical reactions and ionization proceed on the macroscopic gas-dynamics time-scale. The developed model is applied to simulate the flow behind a plane shock wave under initial conditions characteristic for the spacecraft re-entry from an interplanetary flight (Hermes and Fire II experiments). Fluid-dynamic parameters behind the shock wave as well as transport coefficients and the heat flux are calculated for the (N{sub 2}/N{sub 2}{sup +}/N/N{sup +}/e{sup −}) mixture. The effect of electronic excitation on kinetics, dynamics and heat transfer is analyzed. Whereas the contribution of electronic degrees of freedom to the flow macroparameters is negligible, their influence on the heat flux is found to be important under conditions of Hermes re-entry.

  7. KOI-54: The Kepler Discovery of Tidally Excited Pulsations and Brightenings in a Highly Eccentric Binary

    NASA Astrophysics Data System (ADS)

    Welsh, William F.; Orosz, Jerome A.; Aerts, Conny; Brown, Timothy M.; Brugamyer, Erik; Cochran, William D.; Gilliland, Ronald L.; Guzik, Joyce Ann; Kurtz, D. W.; Latham, David W.; Marcy, Geoffrey W.; Quinn, Samuel N.; Zima, Wolfgang; Allen, Christopher; Batalha, Natalie M.; Bryson, Steve; Buchhave, Lars A.; Caldwell, Douglas A.; Gautier, Thomas N., III; Howell, Steve B.; Kinemuchi, K.; Ibrahim, Khadeejah A.; Isaacson, Howard; Jenkins, Jon M.; Prsa, Andrej; Still, Martin; Street, Rachel; Wohler, Bill; Koch, David G.; Borucki, William J.

    2011-11-01

    Kepler observations of the star HD 187091 (KIC 8112039, hereafter KOI-54) revealed a remarkable light curve exhibiting sharp periodic brightening events every 41.8 days with a superimposed set of oscillations forming a beating pattern in phase with the brightenings. Spectroscopic observations revealed that this is a binary star with a highly eccentric orbit, e = 0.83. We are able to match the Kepler light curve and radial velocities with a nearly face-on (i = 5fdg5) binary star model in which the brightening events are caused by tidal distortion and irradiation of nearly identical A stars during their close periastron passage. The two dominant oscillations in the light curve, responsible for the beating pattern, have frequencies that are the 91st and 90th harmonic of the orbital frequency. The power spectrum of the light curve, after removing the binary star brightening component, reveals a large number of pulsations, 30 of which have a signal-to-noise ratio gsim7. Nearly all of these pulsations have frequencies that are either integer multiples of the orbital frequency or are tidally split multiples of the orbital frequency. This pattern of frequencies unambiguously establishes the pulsations as resonances between the dynamic tides at periastron and the free oscillation modes of one or both of the stars. KOI-54 is only the fourth star to show such a phenomenon and is by far the richest in terms of excited modes. Based in part on observations obtained at the W. M. Keck Observatory, which is operated by the University of California and the California Institute of Technology.

  8. Exploring and Modeling High-excitation Emission in the Ejecta and the Wind of Eta Carinae

    NASA Astrophysics Data System (ADS)

    Mehner, Andrea

    Eta Carinae is the most massive, most luminous star in our region of the Galaxy. It is an evolved massive star and therefore provides many clues to the fate of the most massive stars. In the 1840s its unstable nature culminated in the Great Eruption when it briefly became the second brightest star in the sky and ejected more than ten solar masses, which today enshroud the surviving star as a bipolar nebula. Every 5.54 years Eta Car's photometry and spectra show dramatic changes which last for several months. Combining data from HST/STIS, Gemini-S/GMOS, and VLT/UVES from 1998 to 2010, I analyzed two spectroscopic cycles. Observations with a variety of different slit position angles made it possible to map the emission across the nebula and the complex outer ejecta of Eta Car permit to observe the star at different stellar latitudes via reflected light. The spectroscopic cycles are thought to be regulated by a hot companion star and therefore give us information to the nature and orbit of the stars hidden behind Eta Car's opaque wind. The observations, covering more than 10 years, made it also possible to observe the ongoing long-term recovery from the Great Eruption. Topics covered in this thesis include: 1) spatial and temporal behavior of the high-excitation emission lines, 2) parameters of the secondary star, 3) He II 4687 emission during the 2009 "Event," 4) changing wind structure during the 2009 "Event," 5) origin of the He I lines, and 6) major changes in the broad-line wind spectrum indicating a decrease in Eta Car's wind density.

  9. Structure of Low-Lying Excited States of Guanine in DNA and Solution: Combined Molecular Mechanics and High-Level Coupled Cluster Studies

    DOE PAGESBeta

    Kowalski, Karol; Valiev, Marat

    2007-01-01

    High-level ab-initio equation-of-motion coupled-cluster methods with singles, doubles, and noniterative triples are used, in conjunction with the combined quantum mechanical molecular mechanics approach, to investigate the structure of low-lying excited states of the guanine base in DNA and solvated environments. Our results indicate that while the excitation energy of the first excited state is barely changed compared to its gas-phase counterpart, the excitation energy of the second excited state is blue-shifted by 0.24 eV.

  10. Energy, fine structure, hyperfine structure, and radiative transition rates of the high-lying multi-excited states for B-like neon

    NASA Astrophysics Data System (ADS)

    Zhang, Chun Mei; Chen, Chao; Sun, Yan; Gou, Bing Cong; Shao, Bin

    2015-04-01

    The Rayleigh-Ritz variational method with multiconfiguration interaction wave functions is used to obtain the energies of high-lying multi-excited quartet states 1 s 22 s2 pnl and 1 s 22 p 2 nl 4Pe,o ( n ≥ 2) in B-like neon, including the mass polarization and relativistic corrections. The fine structure and hyperfine structure of the excited quartet states for this system are investigated. Configuration structures of the high-lying multi-excited series are further identified by relativistic corrections and fine structure splittings. The transition rates and wavelengths are also calculated. Calculated wavelengths include the quantum electrodynamic effects. The results are compared with other theoretical and experimental data in the literature.

  11. [Thermoelastic excitation of acoustic waves in biological models under the effect of the high peak-power pulsed electromagnetic radiation of extremely high frequency].

    PubMed

    Gapeev, A B; Rubanik, A V; Pashovkin, T N; Chemeris, N K

    2007-01-01

    The capability of high peak-power pulsed electromagnetic radiation of extremely high frequency (35,27 GHz, pulse widths of 100 and 600 ns, peak power of 20 kW) to excite acoustic waves in model water-containing objects and muscular tissue of animals has been experimentally shown for the first time. The amplitude and duration of excited acoustic pulses are within the limits of accuracy of theoretical assessments and have a complex nonlinear dependence on the energy input of electromagnetic radiation supplied. The velocity of propagation of acoustic pulses in water-containing models and isolated muscular tissue of animals was close to the reference data. The excitation of acoustic waves in biological systems under the action of high peak-power pulsed electromagnetic radiation of extremely high frequency is the important phenomenon, which essentially contributes to the understanding of the mechanisms of biological effects of these electromagnetic fields.

  12. Oxygen from the λ7774 High-Excitation Triplet in Open Cluster Dwarfs: Hyades

    NASA Astrophysics Data System (ADS)

    Schuler, Simon C.; King, Jeremy R.; Terndrup, Donald M.; Pinsonneault, Marc H.; Murray, Norman; Hobbs, L. M.

    2006-01-01

    Oxygen abundances have been derived from the near-IR, high-excitation O I λ7774 triplet in high-resolution, high signal-to-noise ratio spectra of 45 Hyades dwarfs using standard one-dimensional, plane-parallel LTE models. Effective temperatures of the stellar sample range from 4319 to 6301 K, and the derived relative O abundances as a function of Teff evince a trichotomous morphology. At Teff>6100 K, there is evidence of an increase in the O abundances with increasing Teff, consistent with non-LTE (NLTE) predictions. At intermediate Teff (5450 K<=Teff<=6100 K), the O abundances are flat, and star-to-star values are in good agreement, having a mean value of [O/H]=+0.25+/-0.02 however, systematic errors at the <~0.10 dex level might exist. The O abundances for stars with Teff<=5450 K show a striking increase with decreasing Teff, in stark contrast to expectations and canonical NLTE calculations. The cool Hyades triplet results are compared to those recently reported for dwarfs in the Pleiades cluster and the UMa moving group; qualitative differences between the trends observed in these stellar aggregates point to a possible age-related diminution of triplet abundance trends in cool open cluster dwarfs. Correlations with age-related phenomena, i.e., chromospheric activity and photospheric spots, faculae, and/or plages, are investigated. No correlation with Ca II H+K chromospheric activity indicators is observed. Multicomponent LTE ``toy'' models have been constructed in order to simulate photospheric temperature inhomogeneities that could arise from the presence of starspots, and we demonstrate that photospheric spots are a plausible source of the triplet trends among the cool dwarfs. Based on observations obtained with the Mayall 4 m telescope at Kitt Peak National Observatory, a division of the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National

  13. High-frequency collective excitations in molten and glassy Te studied by inelastic neutron scattering

    SciTech Connect

    Ruiz-Martin, M. D.; Jimenez-Ruiz, M.; Bermejo, F. J.

    2006-03-01

    The spectra of collective excitations of liquid and glassy tellurium have been studied by means of inelastic neutron scattering. Here we report on the dynamics of liquid Te as measured at two different temperatures, just above melting (T{sub m}=723 K) and at {approx}1000 K as well as the glass that is studied at room temperature. Estimates for the velocity of propagating excitations for both temperatures have been obtained from the experimental data, and a contrasting behavior is found with respect to anomalies shown by the adiabatic sound velocity measured by ultrasound methods. The origin of such differences is finally discussed.

  14. Theoretical Studies of Possible Synthetic Routes for the High Energy Density Material Td N4: Excited Electronic States

    NASA Technical Reports Server (NTRS)

    Lee, Timothy J.; Dateo, Christopher E.

    2001-01-01

    Vertical electronic excitation energies for single states have been computed for the high energy density material (HEDM) Td N4 in order to assess possible synthetic routes that originate from excited electronic states of N2 molecules. Several ab initio theoretical approaches have been used, including complete active space self-consistent field (CASSCF), state averaged CASSCF (SA-CASSCF), singles configuration interaction (CIS), CIS with second-order and third-order correlation corrections [CIS(D)) and CIS(3)], and linear response singles and doubles coupled-cluster (LRCCSD), which is the highest level of theory employed. Standard double zeta polarized (DZP) and triple zeta double polarized (TZ2P) one-particle basis sets were used. The CASSCF calculations are found to overestimate the excitation energies, while the SA-CASSCF approach rectifies this error to some extent, but not completely. The accuracy of the CIS calculations varied depending on the particular state, while the CIS(D), CIS(3), and LRCCSD results are in generally good agreement. Based on the LRCCSD calculations, the lowest six excited singlet states are 9.35(l(sup)T1), 10.01(l(sup)T2), 10.04(1(sup)A2), 10.07(1(sup)E), 10.12(2(sup)T1), and 10.42(2(sup)T2) eV above the ground state, respectively. Comparison of these excited state energies with the energies of possible excited states of N2+N2 fragments, leads us to propose that the most likely synthetic route for Td N4 involving this mechanism arises from combination of two bound quintet states of N2.

  15. A full-spectrum analysis of high-speed train interior noise under multi-physical-field coupling excitations

    NASA Astrophysics Data System (ADS)

    Zheng, Xu; Hao, Zhiyong; Wang, Xu; Mao, Jie

    2016-06-01

    High-speed-railway-train interior noise at low, medium, and high frequencies could be simulated by finite element analysis (FEA) or boundary element analysis (BEA), hybrid finite element analysis-statistical energy analysis (FEA-SEA) and statistical energy analysis (SEA), respectively. First, a new method named statistical acoustic energy flow (SAEF) is proposed, which can be applied to the full-spectrum HST interior noise simulation (including low, medium, and high frequencies) with only one model. In an SAEF model, the corresponding multi-physical-field coupling excitations are firstly fully considered and coupled to excite the interior noise. The interior noise attenuated by sound insulation panels of carriage is simulated through modeling the inflow acoustic energy from the exterior excitations into the interior acoustic cavities. Rigid multi-body dynamics, fast multi-pole BEA, and large-eddy simulation with indirect boundary element analysis are first employed to extract the multi-physical-field excitations, which include the wheel-rail interaction forces/secondary suspension forces, the wheel-rail rolling noise, and aerodynamic noise, respectively. All the peak values and their frequency bands of the simulated acoustic excitations are validated with those from the noise source identification test. Besides, the measured equipment noise inside equipment compartment is used as one of the excitation sources which contribute to the interior noise. Second, a full-trimmed FE carriage model is firstly constructed, and the simulated modal shapes and frequencies agree well with the measured ones, which has validated the global FE carriage model as well as the local FE models of the aluminum alloy-trim composite panel. Thus, the sound transmission loss model of any composite panel has indirectly been validated. Finally, the SAEF model of the carriage is constructed based on the accurate FE model and stimulated by the multi-physical-field excitations. The results show

  16. Highly excited core resonances in photoionization of Fe xvii: Implications for plasma opacities

    SciTech Connect

    Nahar, Sultana N.; Pradhan, Anil K.; Chen Guoxin; Eissner, Werner

    2011-05-15

    A comprehensive study of high-accuracy photoionization cross sections is carried out using the relativistic Breit-Pauli R-matrix (BPRM) method for (h{nu}+Fe xvii {yields} Fe xviii +e). Owing to its importance in high-temperature plasmas, the calculations cover a large energy range, particularly the myriad photoexcitation-of-core (PEC) resonances including the n=3 levels not heretofore considered. The calculations employ a close-coupling wave-function expansion of 60 levels of the core ion Fe xviii ranging over a wide energy range of nearly 900 eV between the n=2 and n=3 levels. Strong-coupling effects due to dipole transition arrays 2p{sup 5}{yields}2p{sup 4}(3s,3d) manifest themselves as large PEC resonances throughout this range and enhance the effective photoionization cross sections orders of magnitude above the background. Comparisons with the erstwhile Opacity Project (OP) and other previous calculations show that the currently available cross sections considerably underestimate the bound-free cross sections. A level-identification scheme is used for spectroscopic designation of the 454 bound fine structure levels of Fe xvii, with n{<=}10, l{<=}9, and 0{<=}J{<=}8 of even and odd parities, obtained using the ab initio BPRM method (compared to 181 LS bound states in the OP work). The calculated energies are compared with those available from the National Institute for Standards and Technology database, which lists 63 levels with very good agreement. Level-specific photoionization cross sections are computed for all levels. In addition, partial cross sections for leaving the core ion Fe xvii in the ground state are also obtained. These results should be relevant to modeling of astrophysical and laboratory plasma sources requiring (i) photoionization rates, (ii) extensive nonlocal-thermodynamic-equilibrium models, (iii) total unified electron-ion recombination rates including radiative and dielectronic recombination, and (iv) plasma opacities. We particularly

  17. Excitation of guided ELF-VLF waves through modification of the F{sub 2} ionospheric layer by high-power radio waves

    SciTech Connect

    Markov, G. A.; Belov, A. S.; Komrakov, G. P.; Parrot, M.

    2012-03-15

    The possibility of controlled excitation of ELF-VLF electromagnetic waves through modification of the F{sub 2} ionospheric layer by high-power high-frequency emission is demonstrated in a natural experiment by using the Sura midlatitude heating facility. The excited low-frequency waves can be used to explore the near-Earth space and stimulate the excitation of a magnetospheric maser.

  18. High-precision Stark shift measurements in excited states of indium using an atomic beam

    NASA Astrophysics Data System (ADS)

    Majumder, P. K.; Carter, A. L.; Augenbraun, B. L.; Rupasinghe, P. M.; Vilas, N. B.

    2016-05-01

    A recent precision measurement in our group of the indium scalar polarizability within the 410 nm 5p1 / 2 --> 6s1 / 2 transition showed excellent agreement with ab initio atomic theory. We are now completing a measurement of the polarizability within the 6s1 / 2 --> 6p1 / 2 excited-state transition. In our experiment, two external cavity semiconductor diode lasers interact transversely with a collimated indium atomic beam. We tune the 410 nm laser to the 5p1 / 2 --> 6s1 / 2 transition, keeping the laser locked to the exact Stark-shifted resonance frequency. We overlap a 1343 nm infrared laser to reach the 6p1 / 2 state. The very small infrared absorption in our atomic beam is detected using two-tone FM spectroscopy. Monitoring the two-step excitation signal in a field-free supplemental vapor cell provides frequency reference and calibration. Precisely calibrated electric fields of 5 - 15 kV/cm produce Stark shifts of order 100 MHz for this excited state. Experimental details, latest results, and comparison to theory will be discussed. In the near future, The same infrared laser will be tuned to 1291 nm to study the scalar and tensor polarizability of the 6p3 / 2 excited state providing a distinct test of atomic theory. Work supported by NSF Grant # 1404206.

  19. Single photon excimer laser photodissociation of highly vibrationally excited polyatomic molecules

    SciTech Connect

    Tiee, J.J.; Wampler, F.B.; Rice, W.W.

    1980-01-01

    The ir + uv photodissociation of SF/sub 6/ has been performed using CO/sub 2/ and ArF lasers. The two-color photolysis significantly enhances the photodissociation process over ArF irradiation alone and is found to preserve the initial isotopic specificity of the ir excitation process.

  20. A doubly averaging method for third body perturbations in planet equator coordinates

    NASA Technical Reports Server (NTRS)

    Hwok, Johnny H.

    1992-01-01

    The first order doubly averaged potential due to third-body gravity is derived in any arbitrary coordinates. The equations of motion are nonsingular at zero eccentricity. The derivation uses a recursive method which allows easy expansion to higher order terms. Instead of using analytical quadrature to obtain the doubly averaged potential, the method presented in this paper simply eliminates the mean anomaly of the perturbed and perturbing bodies by inspection of the recursive formulation. The derivatives of the orbital elements can be numerically integrated rapidly. When a planet equator coordinate system is used, they can be added directly to the derivatives due to gravity harmonics without any coordinate transformation. The method is applied to various high altitude missions. The results are compared with a high precision numerical integration method and are found to provide excellent agreement.

  1. Doubly stochastic Poisson processes in artificial neural learning.

    PubMed

    Card, H C

    1998-01-01

    This paper investigates neuron activation statistics in artificial neural networks employing stochastic arithmetic. It is shown that a doubly stochastic Poisson process is an appropriate model for the signals in these circuits.

  2. Doubly slanted layer structures in holographic gelatin emulsions: solar concentrators

    NASA Astrophysics Data System (ADS)

    Hung, Jenny; Chan, Po Shan; Sun, Caiming; Wing Ho, Choi; Tam, Wing Yim

    2010-04-01

    We have fabricated doubly slanted layer structures in holographic gelatin emulsions using a double-exposure two-beam interference from two light sources with different wavelengths. The doubly slanted layers, with different spacings and overlapping with each other, are fabricated such that they are slanted in opposite directions making a 30° angle with the holographic plate. The doubly slanted layer structures exhibit photonic stop bands corresponding to the two layered structures. More importantly, diffracted light beams from the slanted layers travel in different directions and emerge, through internal reflections, at the opposite edges of the gelatin plate. The doubly slanted layer structures could be used as solar concentrators such that sunlight is separated into different components and steered directly to photovoltaics with the corresponding wavelength sensitivities to enhance energy conversion efficiency.

  3. Signatures of doubly-charged Higgsinos at colliders

    SciTech Connect

    Demir, D. A.; Frank, M.; Turan, I.; Huitu, K.; Rai, S. K.

    2008-11-23

    Several supersymmetric models with extended gauge structures predict light doubly-charged Higgsinos. Their distinctive signature at the large hadron collider is highlighted by studying its production and decay characteristics.

  4. Mechanism for Highly Efficient Non-Radiative Deactivation of Electronic Excitation in Rutin

    NASA Astrophysics Data System (ADS)

    Bondarev, S. L.; Knyukshto, V. N.; Tikhomirov, S. A.; Buganov, O. V.

    2016-01-01

    Steady-state and pulsed spectroscopic methods are used to study the spectroscopic and photophysical properties of the biologically important plant pigment rutin at room temperature and 77 K in organic solvents and a buffer solution at pH 7.0. The large dipole moment μe = 13.3 D of the rutin molecule in a Franck-Condon excited state indicates that rutin is dipolar in this excited state. The nonstationary S1 → Sn induced absorption spectra are characterized by a short-wavelength band at λabs max = 460 nm and low-intensity absorption in the 500-750 range which clearly belongs to associates of rutin. No residual induced absorption which might be related to triplet-triplet T1→Tk transitions in rutin was observed over the entire spectral range for times >50 ns. S1 → S0 fluorescence with a quantum yield Φfl ~ 10-4 was also observed at room temperature. The fluorescence and fluorescence excitation spectra manifest a weak dependence on the excitation and detection wavelengths, which may be related to the presence of conformers in the solution owing to rotation of the phenol B ring around a single 1'-2 bond. Lowering the temperature of a glassy frozen solution of rutin in ethanol to 77 K raises Φfl by a factor of 750. A rate constant kic = 3.7·1011 s-1 for internal conversion from the S1 state at room temperature is calculated from the spectral-luminescence data. It is found that the main channel for exchange of electronic excitation energy in the rutin molecule at room temperature is S1(π,π*) ~~> S0-internal conversion induced by the charge-transfer state.

  5. Production of excited atomic hydrogen and deuterium from H2 and D2 photodissociation

    NASA Astrophysics Data System (ADS)

    Bozek, J. D.; Furst, J. E.; Gay, T. J.; Gould, H.; Kilcoyne, A. L. D.; Machacek, J. R.; Martín, F.; McLaughlin, K. W.; Sanz-Vicario, J. L.

    2006-12-01

    We have measured the production of both Lyα and Hα fluorescence from atomic H and D for the photodissociation of H2 and D2 by linearly polarized photons with energies between 24 and 60 eV. In this energy range, excited photofragments result primarily from the production of doubly excited molecular species which promptly autoionize or dissociate into two neutrals. Our data are compared with ab initio calculations of the dissociation process, in which both doubly excited state production and prompt ionization (non-resonant) channels are considered. Agreement between our experimental data and that of earlier work, and with our theoretical calculations, is qualitative at best.

  6. Relating neutrino masses to dilepton modes of doubly charged scalars

    SciTech Connect

    Chen, Chian-Shu; Geng, C. Q.

    2010-11-15

    We study a model with Majorana neutrino masses generated through doubly charged scalars at two-loop level. We give explicit relationships between the neutrino masses and the same sign dilepton decays of the doubly charged scalars. In particular, we demonstrate that in the tribimaximal limit of the neutrino mixings, the absolute neutrino masses and Majorana phases can be extracted through the measurements of the dilepton modes at colliders.

  7. High-Resolution Laser Spectroscopy of S1-S0 Transition of Naphthalene: Measurement of Vibrationally Excited States

    NASA Astrophysics Data System (ADS)

    Nakano, Takumi; Yamamoto, Ryo; Kasahara, Shunji

    2015-06-01

    Naphthalene is one of the simple polycyclic aromatic molecule, and it is interesting that the excited state dynamics take place. To understand the excited state dynamics, rotationally resolved fluorescence excitation spectra of several vibronic bands were measured. In this work, we have measured high-resolution fluorescence excitation spectra across a single mode laser and molecular beam at light angle. Vibronic bands, which lies 2866 cm -1 and 3068 cm -1 above the 0-0 band (000 + 2866 cm-1 band and 000 + 3068 cm-1 band), were measured. Absolute wavenumber was calibrated with accuracy 0.0002 cm-1 by the measurement of Doppler-free absorption spectrum of I2 molecule and transmitting light intensity of the stabilized etalon. Rotational lines of the 000 + 2866 cm-1 band were almost resolved. A part of the rotational lines were assigned, and several energy shifts were found. On the other hand, rotational lines were not completely resolved for the 000 + 3068 cm-1 band. K. Yoshida, Y. Semba, S. Kasahara, T. Yamanaka, and M. Baba, J. Chem. Phys. 130, 19304 (2009) H. Kato, M. Baba, and S. Kasahara, Bull. Chem. Soc. Jpn. 80, 456 (2007)

  8. Heat generation in an elastic binder system with embedded discrete energetic particles due to high-frequency, periodic mechanical excitation

    NASA Astrophysics Data System (ADS)

    Mares, J. O.; Miller, J. K.; Gunduz, I. E.; Rhoads, J. F.; Son, S. F.

    2014-11-01

    High-frequency mechanical excitation can induce heating within energetic materials and may lead to advances in explosives detection and defeat. In order to examine the nature of this mechanically induced heating, samples of an elastic binder (Sylgard 184) were embedded with inert and energetic particles placed in a fixed spatial pattern and were subsequently excited with an ultrasonic transducer at discrete frequencies from 100 kHz to 20 MHz. The temperature and velocity responses of the sample surfaces suggest that heating due to frictional effects occurred near the particles at excitation frequencies near the transducer resonance of 215 kHz. An analytical solution involving a heat point source was used to estimate heating rates and temperatures at the particle locations in this frequency region. Heating located near the sample surface at frequencies near and above 1 MHz was attributed to viscoelastic effects related to the surface motion of the samples. At elevated excitation parameters near the transducer resonance frequency, embedded particles of ammonium perchlorate and cyclotetramethylene-tetranitramine were driven to chemical decomposition.

  9. Highly-sensitive Eu3+ ratiometric thermometers based on excited state absorption with predictable calibration

    NASA Astrophysics Data System (ADS)

    Souza, Adelmo S.; Nunes, Luiz A. O.; Silva, Ivan G. N.; Oliveira, Fernando A. M.; da Luz, Leonis L.; Brito, Hermi F.; Felinto, Maria C. F. C.; Ferreira, Rute A. S.; Júnior, Severino A.; Carlos, Luís D.; Malta, Oscar L.

    2016-02-01

    Temperature measurements ranging from a few degrees to a few hundreds of Kelvin are of great interest in the fields of nanomedicine and nanotechnology. Here, we report a new ratiometric luminescent thermometer using thermally excited state absorption of the Eu3+ ion. The thermometer is based on the simple Eu3+ energy level structure and can operate between 180 and 323 K with a relative sensitivity ranging from 0.7 to 1.7% K-1. The thermometric parameter is defined as the ratio between the emission intensities of the 5D0 --> 7F4 transition when the 5D0 emitting level is excited through the 7F2 (physiological range) or 7F1 (down to 180 K) level. Nano and microcrystals of Y2O3:Eu3+ were chosen as a proof of concept of the operational principles in which both excitation and detection are within the first biological transparent window. A novel and of paramount importance aspect is that the calibration factor can be calculated from the Eu3+ emission spectrum avoiding the need for new calibration procedures whenever the thermometer operates in different media.Temperature measurements ranging from a few degrees to a few hundreds of Kelvin are of great interest in the fields of nanomedicine and nanotechnology. Here, we report a new ratiometric luminescent thermometer using thermally excited state absorption of the Eu3+ ion. The thermometer is based on the simple Eu3+ energy level structure and can operate between 180 and 323 K with a relative sensitivity ranging from 0.7 to 1.7% K-1. The thermometric parameter is defined as the ratio between the emission intensities of the 5D0 --> 7F4 transition when the 5D0 emitting level is excited through the 7F2 (physiological range) or 7F1 (down to 180 K) level. Nano and microcrystals of Y2O3:Eu3+ were chosen as a proof of concept of the operational principles in which both excitation and detection are within the first biological transparent window. A novel and of paramount importance aspect is that the calibration factor can be

  10. Evidence for a new excitation at the interface between a high-Tc superconductor and a topological insulator

    DOE PAGESBeta

    Zareapour, Parisa; Hayat, Alex; Zhao, Shu Yang F.; Kreshchuk, Michael; Lee, Yong Kiat; Reijnders, Anjan A.; Jain, Achint; Xu, Zhijun; Liu, T. S.; Gu, G. D.; et al

    2014-12-09

    In this research, high-temperature superconductors exhibit a wide variety of novel excitations. If contacted with a topological insulator, the lifting of spin rotation symmetry in the surface states can lead to the emergence of unconventional superconductivity and novel particles. In pursuit of this possibility, we fabricated high critical-temperature (Tc ~ 85 K) superconductor/topological insulator (Bi₂Sr₂CaCu₂O₈₊δ/Bi₂Te₂Se) junctions. Below 75 K, a zero-bias conductance peak (ZBCP) emerges in the differential conductance spectra of this junction. The magnitude of the ZBCP is suppressed at the same rate for magnetic fields applied parallel or perpendicular to the junction. Furthermore, it can still be observedmore » and does not split up to at least 8.5 T. The temperature and magnetic field dependence of the excitation we observe appears to fall outside the known paradigms for a ZBCP.« less

  11. Kinetic Energy Distribution of H(2p) Atoms from Dissociative Excitation of H2

    NASA Technical Reports Server (NTRS)

    Ajello, Joseph M.; Ahmed, Syed M.; Kanik, Isik; Multari, Rosalie

    1995-01-01

    The kinetic energy distribution of H(2p) atoms resulting from electron impact dissociation of H2 has been measured for the first time with uv spectroscopy. A high resolution uv spectrometer was used for the measurement of the H Lyman-alpha emission line profiles at 20 and 100 eV electron impact energies. Analysis of the deconvolved 100 eV line profile reveals the existence of a narrow line peak and a broad pedestal base. Slow H(2p) atoms with peak energy near 80 meV produce the peak profile, which is nearly independent of impact energy. The wings of H Lyman-alpha arise from dissociative excitation of a series of doubly excited Q(sub 1) and Q(sub 2) states, which define the core orbitals. The fast atom energy distribution peaks at 4 eV.

  12. Excitation of high orbital angular momentum Rydberg states with Laguerre-Gauss beams

    NASA Astrophysics Data System (ADS)

    Rodrigues, J. D.; Marcassa, L. G.; Mendonça, J. T.

    2016-04-01

    We consider the excitation of Rydberg states through photons carrying an intrinsic orbital angular momentum degree of freedom. Laguerre-Gauss modes, with a helical wave-front structure, correspond to such a set of laser beams, which carry {{\\ell }}0 units of orbital angular momentum in their propagation direction, with ℓ 0 the winding number. We demonstrate that, in a proper geometry setting, this orbital angular momentum can be transferred to the internal degrees of freedom of the atoms, thus violating the standard dipole selection rules. Higher orbital angular momentum states become accessible through a single photon excitation process. We investigate how the spacial structure of the Laguerre-Gauss beam affects the radial coupling strength, assuming the simplest case of hydrogen-like wavefunctions. Finally we discuss a generalization of the angular momentum coupling, in order to include the effects of the fine and hyperfine splitting, in the context of the Wigner-Eckart theorem.

  13. High spin spectroscopy near the N=Z line: Channel selection and excitation energy systematics

    SciTech Connect

    Svensson, C.E.; Cameron, J.A.; Flibotte, S.

    1996-12-31

    The total {gamma}-ray and charged-particle energies emitted in fusion-evaporation reactions leading to N=Z compound systems in the A = 50-70 mass region have been measured with the 8{pi} {gamma}-ray spectrometer and the miniball charged-particle detector array. A new method of channel selection has been developed which combines particle identification with these total energy measurements and greatly improves upon the selectivity possible with particle detection alone. In addition, the event by event measurement of total {gamma}-ray energies using the BGO ball of the 8{pi} spectrometer has allowed a determination of excitation energies following particle evaporation for a large number of channels in several different reactions. The new channel selection procedure and excitation energy systematics are illustrated with data from the reaction of {sup 24}Mg on {sup 40}Ca at E{sub lab} = 80MeV.

  14. Mechanisms of doubly-vergent vs. single-sided orogens: insights from numerical modelling

    NASA Astrophysics Data System (ADS)

    Vogt, K.; Matenco, L. C.; Gerya, T.; Cloetingh, S.

    2014-12-01

    Zones of continent collision form mountain ranges with high topographies and complex geometries. Compressional stresses during ongoing convergence result in crustal thickening and localized deformation, where crustal material is transported and redistributed within the orogen. We use numerical high-resolution thermo-mechanical models to investigate the physical processes of continent collision zones and its implications on rock exhumation. We demonstrate that compression of two continental blocks, separated by a rheologically weak suture zone can result in (i) doubly-vergent (Fig. A) or (ii) single-sided orogens (Fig. B), with distinct geometries, deformation and exhumation patterns. The transition between these different modes of collision is strongly controlled by the rheology of the continental lithosphere and therefore its temperature distribution. Doubly-vergent orogens form at relatively high thermal gradients, while single-sided orogens are typical for lower ones. Doubly-vergent orogens (Fig. A) are formed in response to the gradual accretion of crustal material to the upper plate along retro-shears. In these models continental subduction results in upper plate deformation and nested exhumation against retro-shears. Typical examples include the collision recorded by the Swiss Alps and the Pyrenees. In contrast, single-sided orogens are characterized by large-scale lower plate deformation and are accompanied by the subduction of lower crustal material (Fig. B). Modeling infers that shortening and associated exhumation will gradually propagate towards the foreland. In this situation, no significant retro-shear formation is observed, which is in agreement with recent physical modelling studies on deformation of the continental lithosphere [Willingshofer et al., 2013]. Natural examples of such single sided orogens are common in the Mediterranean (Carpathians, Dinarides, Apennines, Betics) or the SE Asia subduction zones. We conclude that deformation and

  15. Ionization steps and phase-space metamorphoses in the pulsed microwave ionization of highly excited hydrogen atoms

    SciTech Connect

    Bayfield, J.E.; Luie, S.Y.; Perotti, L.C.; Skrzypkowski, M.P.

    1996-01-01

    As the peak electric field of the microwave pulse is increased, steps in the classical microwave ionization probability of the highly excited hydrogen atom are produced by phase-space metamorphosis. They arise from new layers of Kolmogorov-Arnold-Moser (KAM) islands being exposed as KAM surfaces are destroyed. Both quantum numerical calculations and laboratory experiments exhibit the ionization steps, showing that such metamorphoses influence pulsed semiclassical systems. {copyright} {ital 1996 The American Physical Society.}

  16. Low-threshold and high efficiency lasing upon band-edge excitation in a cholesteric liquid crystal

    NASA Astrophysics Data System (ADS)

    Matsuhisa, Yuko; Huang, Yuhua; Zhou, Ying; Wu, Shin-Tson; Ozaki, Ryotaro; Takao, Yuuki; Fujii, Akihiko; Ozaki, Masanori

    2007-02-01

    A low threshold and high efficiency laser based on dye-doped cholesteric liquid crystals (CLCs) is demonstrated using an input excitation with the same handedness of circular polarization as the helical structure of the sample at the shorter wavelength band edge of the reflection band. The responsible mechanism originates from the dramatic increase of the optical density of state (DOS) at the band edges. The calculated DOS of the CLC system confirms the authors' experimental results.

  17. Recent Excitation, Charge Exchange, and Lifetime Results in Highly Charged Ions Relevant to Stellar, Interstellar, Solar and Comet Phenomena

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Hossain, S.; Mawhorter, R. J.; Smith, S. J.

    2006-01-01

    Recent JPL absolute excitation and charge exchange cross sections, and measurements of lifetimes of metastable levels in highly-charged ions (HCIs) are reported. These data provide benchmark comparisons to results of theoretical calculations. Theoretical approaches can then be used to calculate the vast array of data which cannot be measured due to experimental constraints. Applications to the X-ray emission from comets are given.

  18. Quantum electrodynamical theory of high-efficiency excitation energy transfer in laser-driven nanostructure systems

    NASA Astrophysics Data System (ADS)

    Weeraddana, Dilusha; Premaratne, Malin; Gunapala, Sarath D.; Andrews, David L.

    2016-08-01

    A fundamental theory is developed for describing laser-driven resonance energy transfer (RET) in dimensionally constrained nanostructures within the framework of quantum electrodynamics. The process of RET communicates electronic excitation between suitably disposed emitter and detector particles in close proximity, activated by the initial excitation of the emitter. Here, we demonstrate that the transfer rate can be significantly increased by propagation of an auxiliary laser beam through a pair of nanostructure particles. This is due to the higher order perturbative contribution to the Förster-type RET, in which laser field is applied to stimulate the energy transfer process. We construct a detailed picture of how excitation energy transfer is affected by an off-resonant radiation field, which includes the derivation of second and fourth order quantum amplitudes. The analysis delivers detailed results for the dependence of the transfer rates on orientational, distance, and laser intensity factor, providing a comprehensive fundamental understanding of laser-driven RET in nanostructures. The results of the derivations demonstrate that the geometry of the system exercises considerable control over the laser-assisted RET mechanism. Thus, under favorable conformational conditions and relative spacing of donor-acceptor nanostructures, the effect of the auxiliary laser beam is shown to produce up to 70% enhancement in the energy migration rate. This degree of control allows optical switching applications to be identified.

  19. Highly-sensitive Eu(3+) ratiometric thermometers based on excited state absorption with predictable calibration.

    PubMed

    Souza, Adelmo S; Nunes, Luiz A O; Silva, Ivan G N; Oliveira, Fernando A M; da Luz, Leonis L; Brito, Hermi F; Felinto, Maria C F C; Ferreira, Rute A S; Júnior, Severino A; Carlos, Luís D; Malta, Oscar L

    2016-03-01

    Temperature measurements ranging from a few degrees to a few hundreds of Kelvin are of great interest in the fields of nanomedicine and nanotechnology. Here, we report a new ratiometric luminescent thermometer using thermally excited state absorption of the Eu(3+) ion. The thermometer is based on the simple Eu(3+) energy level structure and can operate between 180 and 323 K with a relative sensitivity ranging from 0.7 to 1.7% K(-1). The thermometric parameter is defined as the ratio between the emission intensities of the (5)D0 → (7)F4 transition when the (5)D0 emitting level is excited through the (7)F2 (physiological range) or (7)F1 (down to 180 K) level. Nano and microcrystals of Y2O3:Eu(3+) were chosen as a proof of concept of the operational principles in which both excitation and detection are within the first biological transparent window. A novel and of paramount importance aspect is that the calibration factor can be calculated from the Eu(3+) emission spectrum avoiding the need for new calibration procedures whenever the thermometer operates in different media.

  20. Time reversal communication over doubly spread channels.

    PubMed

    Zeng, Wen-Jun; Jiang, Xue

    2012-11-01

    Conventional time reversal can mitigate multipath delay dispersion by temporal focusing. But it is not applicable to time-varying channels with a Doppler spread. Although recently time reversal communication has been adapted to time-variant channels, the modified technique requires frequent channel updates to track channel variations and cannot handle large Doppler spread, which means that it cannot achieve frequency focusing. In this paper, two time reversal receivers for underwater acoustic communications over doubly spread channels are proposed. The proposed approach, which can be interpreted as time-frequency channel matching, is based on the channel spreading function rather than impulse response adopted by the existing techniques; this leads to much less frequent channel updates. Unlike existing methods that only correct a single Doppler shift, the proposed approach uses a rake-like structure to compensate for multiple Doppler shifts and hence can eliminate severe Doppler spread induced by temporal channel variations. Simulation results verify the effectiveness of the proposed approach, indicating that it can simultaneously counteract delay and Doppler spreads, achieving both temporal and frequency focusing.

  1. Doubly stochastic coherence in complex neuronal networks

    NASA Astrophysics Data System (ADS)

    Gao, Yang; Wang, Jianjun

    2012-11-01

    A system composed of coupled FitzHugh-Nagumo neurons with various topological structures is investigated under the co-presence of two independently additive and multiplicative Gaussian white noises, in which particular attention is paid to the neuronal networks spiking regularity. As the additive noise intensity and the multiplicative noise intensity are simultaneously adjusted to optimal values, the temporal periodicity of the output of the system reaches the maximum, indicating the occurrence of doubly stochastic coherence. The network topology randomness exerts different influences on the temporal coherence of the spiking oscillation for dissimilar coupling strength regimes. At a small coupling strength, the spiking regularity shows nearly no difference in the regular, small-world, and completely random networks. At an intermediate coupling strength, the temporal periodicity in a small-world neuronal network can be improved slightly by adding a small fraction of long-range connections. At a large coupling strength, the dynamical behavior of the neurons completely loses the resonance property with regard to the additive noise intensity or the multiplicative noise intensity, and the spiking regularity decreases considerably with the increase of the network topology randomness. The network topology randomness plays more of a depressed role than a favorable role in improving the temporal coherence of the spiking oscillation in the neuronal network research study.

  2. Nuclear structure in the neutron-rich doubly magic sup 78 Ni region

    SciTech Connect

    Hill, J.C.; Wohn, F.K.; Winger, J.A.; Warburton, E.K.; Gill, R.L.; Schuhmann, R.B.; Brookhaven National Lab., Upton, NY; Clark Univ., Worcester, MA )

    1989-01-01

    The magic numbers Z=28 and N=50 imply that very neutron-rich {sup 78}Ni, which has not yet been observed, is doubly magic. The {sup 78}Ni region was investigated by studying the N=50 isotones and neutron-rich Zn isotopes. Results on the level structure of {sup 83}As, {sup 74}Zn, and {sup 76}Zn populated in the decays of {sup 83}Ge, {sup 74}Cu, and {sup 76}Cu are presented. The parent nuclides were produced and mass separated using the TRISTAN facility on-line to the High-Flux Beam Reactor at Brookhaven. The systematics of the N=50 isotones and even-A Zn isotopes are discussed and compared with shell-model calculations involving active nucleons outside of a {sup 78}Ni and {sup 66}Ni core, respectively. The extent to which the {sup 78}Ni region can be considered doubly magic is assessed. 43 refs., 7 figs.

  3. Ultraviolet spectrum and probable chemical composition of the high-excitation planetary nebula M1-1.

    PubMed

    Aller, L H; Keyes, C D; Feibelman, W A

    1986-05-01

    One of the highest excitation planetary nebulae known, M1-1, was studied with the image-tube scanner on the Shane 3-m telescope at Lick Observatory and with the International Ultraviolet Explorer. Large fractions of abundant elements such as C, N, O, S, and Ar exist in unobservable stages of ionization. Hence, it is difficult to establish the chemical composition of this nebula. The logarithmic abundance values of various elements compared with those of the Sun appear to be as follows: [Table: see text] Here log N(H) = 12. In contrast to NGC 6537, the composition of M1-1 does not appear to differ markedly from that of the Sun. N may be enhanced but there is no enhancement of He or C. In spite of its high excitation and its presumed origin from a relatively massive star, M1-1 shows no evidence for pronounced nuclear processing. PMID:16593688

  4. High-sensitivity label-free optical fiber optrodes based on the excitation of Bloch surface waves

    NASA Astrophysics Data System (ADS)

    Scaravilli, M.; Castaldi, G.; Cusano, A.; Galdi, V.

    2016-05-01

    In this study, the possibility to excite Bloch surface waves (BSWs) on the tip of a single-mode optical fiber is explored for the first time. In particular, we first show the possibility to achieve an on-tip excitation of BSWs, with optimized characteristic of the arising resonances, via an "all-fiber" grating-coupled configuration. Furthermore, envisioning novel high-performance fiber tip nanoprobes for label-free biosensing, we introduce an ad hoc design aimed at maximizing the refractive-index sensitivity. Numerical results indicate that the estimated sensitivities are comparable with those exhibited by current plasmonic lab-on-tip bio-probes, but are accompanied by a higher spectral selectivity. Therefore, this preliminary work paves the way to the development of new classes of miniaturized surface-wave optical fiber devices for low-detection-limit label-free chemical and biological sensing.

  5. Ultraviolet spectrum and probable chemical composition of the high-excitation planetary nebula M1-1

    PubMed Central

    Aller, Lawrence H.; Keyes, Charles D.; Feibelman, Walter A.

    1986-01-01

    One of the highest excitation planetary nebulae known, M1-1, was studied with the image-tube scanner on the Shane 3-m telescope at Lick Observatory and with the International Ultraviolet Explorer. Large fractions of abundant elements such as C, N, O, S, and Ar exist in unobservable stages of ionization. Hence, it is difficult to establish the chemical composition of this nebula. The logarithmic abundance values of various elements compared with those of the Sun appear to be as follows: [Table: see text] Here log N(H) = 12. In contrast to NGC 6537, the composition of M1-1 does not appear to differ markedly from that of the Sun. N may be enhanced but there is no enhancement of He or C. In spite of its high excitation and its presumed origin from a relatively massive star, M1-1 shows no evidence for pronounced nuclear processing. PMID:16593688

  6. Theoretical study of Raman chirped adiabatic passage by X-ray absorption spectroscopy: Highly excited electronic states and rotational effects

    SciTech Connect

    Engin, Selma; Sisourat, Nicolas Selles, Patricia; Taïeb, Richard; Carniato, Stéphane

    2014-06-21

    Raman Chirped Adiabatic Passage (RCAP) is an efficient method to climb the vibrational ladder of molecules. It was shown on the example of fixed-in-space HCl molecule that selective vibrational excitation can thus be achieved by RCAP and that population transfer can be followed by X-ray Photoelectron spectroscopy [S. Engin, N. Sisourat, P. Selles, R. Taïeb, and S. Carniato, Chem. Phys. Lett. 535, 192–195 (2012)]. Here, in a more detailed analysis of the process, we investigate the effects of highly excited electronic states and of molecular rotation on the efficiency of RCAP. Furthermore, we propose an alternative spectroscopic way to monitor the transfer by means of X-ray absorption spectra.

  7. The luminescence of BaF{sub 2} nanoparticles upon high-energy excitation

    SciTech Connect

    Vistovskyy, V. V. Zhyshkovych, A. V.; Halyatkin, O. O.; Voloshinovskii, A. S.; Mitina, N. E.; Zaichenko, A. S.; Rodnyi, P. A.; Vasil'ev, A. N.; Gektin, A. V.

    2014-08-07

    The dependence of X-ray excited luminescence intensity on BaF{sub 2} nanoparticle size was studied. A sharp decrease of self-trapped exciton luminescence intensity was observed when the nanoparticle size is less than 80 nm. The main mechanism of the luminescence quenching is caused by the escape of electrons from the nanoparticles. Escape of electrons from nanoparticles is confirmed by the considerable increase of luminescence intensity of the polystyrene scintillator with embedded BaF{sub 2} nanoparticles comparing with pure polystyrene scintillator.

  8. UV absorption study of collisional energy transfer in vibrationally highly excited SO/sub 2/ molecules

    SciTech Connect

    Heymann, M.; Hippler, H.; Nahr, D.; Plach, H.J.; Troe, J.

    1988-09-22

    Transient UV absorption spectra after UV laser excitation of SO/sub 2/ were recorded and analyzed with respect to collisional energy transfer. Byuse of previously determined calibration curves, the absorption-time signals were converted into average energy-number of collision profiles. Energy-dependent average energies transferred per collision (..delta..E) were derived for 22 different collision partners. The temperature dependence of (..delta..E) was determined over the range 300-1500 K by experiments in a CO/sub 2/ CW laser-heated reactor and in shock waves.

  9. Laser double-resonance studies of electronic spectroscopy and state-resolved collisional relaxation in highly vibrationally excited acetylene

    SciTech Connect

    Tobiason, J.D.

    1992-01-01

    Vibrational overtone excitation combined with laser-induced fluorescence detection of acetylene molecules permits rotation-selected spectroscopy of the ([tilde A][sup 1]A[sub u]) electronic state and direct, state-resolved measurements of collisional energy transfer in the highly vibrationally excited ground electronic state. The author assigns energies of 1,045 transitions to previously unobserved ungerade vibrational states 2800-4500 cm[sup [minus]1] above the [tilde A] state origin. An analysis yields frequencies of 2856.4 and 3894.3 cm[sup [minus]1] for [nu][sub v][prime] and [nu][sub 3][prime] + [nu][sub 5][prime]. The author performs the first normal coordinate analysis of [tilde A] state acetylene based only on directly observed fundamentals. The spectroscopy measurements enable double-resonance experiments on the collisional dynamics of highly vibrationally excited acetylene. The quenching rate for single rotational states is twice the Lennard-Jones gas kinetic rate and fairly independent of vibrational energy level. Collision-induced detection of vibrational overtone excitation under single collision conditions allows direct measurements of state-of-state rotational and vibrational energy transfer. A collision-induced spectrum obtained by this new technique immediately identifies transfer channels and the [Delta]J and [Delta]E dependence of the transfer rates. The author observes changes of [vert bar][Delta]J[vert bar] and [Delta]E [approx] 3kT in a single collision. Directly measured rates for one set of vibrational relaxation pathways account for [approximately]3% of the total relaxation rate. The author also observes other vibrational relaxation pathways. The available pathways suggest that vibrational relaxation accounts for the rest of the total relaxation. Changes of [vert bar]J[vert bar] = 18 and [vert bar][Delta]E[vert bar] [approximately] 500 cm[sup [minus]1] in a single collision are observed.

  10. Trajectory and Model Studies of Collisions of Highly Excited Methane with Water Using an ab Initio Potential.

    PubMed

    Conte, Riccardo; Houston, Paul L; Bowman, Joel M

    2015-12-17

    Quasi-classical trajectory studies have been performed for the collision of internally excited methane with water using an accurate methane-water potential based on a full-dimensional, permutationally invariant analytical representation of energies calculated at a high level of theory. The results suggest that most energy transfer takes place at impact parameters smaller than about 8 Bohr; collisions at higher impact parameters are mostly elastic. Overall, energy transfer is fairly facile, with values for ⟨ΔEdown⟩ and ⟨ΔEup⟩ approaching almost 2% of the total excitation energy. A classical model previously developed for the collision of internally excited molecules with atoms (Houston, P. L.; Conte, R.; Bowman, J. M. J. Phys. Chem. A 2015, 119, 4695-4710) has been extended to cover collisions of internally excited molecules with other molecules. For high initial rotational levels, the agreement with the trajectory results is quite good (R(2) ≈ 0.9), whereas for low initial rotational levels it is only fair (R(2) ≈ 0.7). Both the model and the trajectories can be characterized by a four-dimensional joint probability distribution, P(J1,f,ΔE1,J2,f,ΔE2), where J1,f and J2,f are the final rotational levels of molecules 1 and 2 and ΔE1 and ΔE2 are the respective changes in internal energy. A strong anticorrelation between ΔE1 and ΔE2 is observed in both the model and trajectory results and can be explained by the model. There is evidence in the trajectory results for a small amount of V ↔ V energy transfer from the water, which has low internal energy, to the methane, which has substantial internal energy. This observation suggests that V ↔ V energy transfer in the other direction also occurs. PMID:26299678

  11. Distinct changes in cortical and spinal excitability following high-frequency repetitive TMS to the human motor cortex.

    PubMed

    Quartarone, Angelo; Bagnato, Sergio; Rizzo, Vincenzo; Morgante, Francesca; Sant'angelo, Antonio; Battaglia, Fortunato; Messina, Corrado; Siebner, Hartwig Roman; Girlanda, Paolo

    2005-02-01

    It has been shown that high-frequency repetitive transcranial magnetic stimulation (rTMS) to the human primary motor hand area (M1-HAND) can induce a lasting increase in corticospinal excitability. Here we recorded motor evoked potentials (MEPs) from the right first dorsal interosseus muscle to investigate how sub-threshold high-frequency rTMS to the M1-HAND modulates cortical and spinal excitability. In a first experiment, we gave 1500 stimuli of 5 Hz rTMS. At an intensity of 90% of active motor threshold, rTMS produced no effect on MEP amplitude at rest. Increasing the intensity to 90% of resting motor threshold (RMT), rTMS produced an increase in MEP amplitude. This facilitatory effect gradually built up during the course of rTMS, reaching significance after the administration of 900 stimuli. In a second experiment, MEPs were elicited during tonic contraction using weak anodal electrical or magnetic test stimuli. 1500 (but not 600) conditioning stimuli at 90% of RMT induced a facilitation of MEPs in the contracting FDI muscle. In a third experiment, 600 conditioning stimuli were given at 90% of RMT to the M1-HAND. Using two well-established conditioning-test paradigms, we found a decrease in short-latency intracortical inhibition (SICI), and a facilitation of the first peak of facilitatory I-waves interaction (SICF). There was no correlation between the relative changes in SICI and SICF. These results demonstrate that subthreshold 5 Hz rTMS can induce lasting changes in specific neuronal subpopulations in the human corticospinal motor system, depending on the intensity and duration of rTMS. Short 5 Hz rTMS (600 stimuli) at 90% of RMT can selectively shape the excitability of distinct intracortical circuits, whereas prolonged 5 Hz rTMS (> or =900 stimuli) provokes an overall increase in excitability of the corticospinal output system, including spinal motoneurones.

  12. Trajectory and Model Studies of Collisions of Highly Excited Methane with Water Using an ab Initio Potential.

    PubMed

    Conte, Riccardo; Houston, Paul L; Bowman, Joel M

    2015-12-17

    Quasi-classical trajectory studies have been performed for the collision of internally excited methane with water using an accurate methane-water potential based on a full-dimensional, permutationally invariant analytical representation of energies calculated at a high level of theory. The results suggest that most energy transfer takes place at impact parameters smaller than about 8 Bohr; collisions at higher impact parameters are mostly elastic. Overall, energy transfer is fairly facile, with values for ⟨ΔEdown⟩ and ⟨ΔEup⟩ approaching almost 2% of the total excitation energy. A classical model previously developed for the collision of internally excited molecules with atoms (Houston, P. L.; Conte, R.; Bowman, J. M. J. Phys. Chem. A 2015, 119, 4695-4710) has been extended to cover collisions of internally excited molecules with other molecules. For high initial rotational levels, the agreement with the trajectory results is quite good (R(2) ≈ 0.9), whereas for low initial rotational levels it is only fair (R(2) ≈ 0.7). Both the model and the trajectories can be characterized by a four-dimensional joint probability distribution, P(J1,f,ΔE1,J2,f,ΔE2), where J1,f and J2,f are the final rotational levels of molecules 1 and 2 and ΔE1 and ΔE2 are the respective changes in internal energy. A strong anticorrelation between ΔE1 and ΔE2 is observed in both the model and trajectory results and can be explained by the model. There is evidence in the trajectory results for a small amount of V ↔ V energy transfer from the water, which has low internal energy, to the methane, which has substantial internal energy. This observation suggests that V ↔ V energy transfer in the other direction also occurs.

  13. Study of doubly strange systems using stored antiprotons

    NASA Astrophysics Data System (ADS)

    Singh, B.; Erni, W.; Krusche, B.; Steinacher, M.; Walford, N.; Liu, B.; Liu, H.; Liu, Z.; Shen, X.; Wang, C.; Zhao, J.; Albrecht, M.; Erlen, T.; Fink, M.; Heinsius, F.; Held, T.; Holtmann, T.; Jasper, S.; Keshk, I.; Koch, H.; Kopf, B.; Kuhlmann, M.; Kümmel, M.; Leiber, S.; Mikirtychyants, M.; Musiol, P.; Mustafa, A.; Pelizäus, M.; Pychy, J.; Richter, M.; Schnier, C.; Schröder, T.; Sowa, C.; Steinke, M.; Triffterer, T.; Wiedner, U.; Ball, M.; Beck, R.; Hammann, C.; Ketzer, B.; Kube, M.; Mahlberg, P.; Rossbach, M.; Schmidt, C.; Schmitz, R.; Thoma, U.; Urban, M.; Walther, D.; Wendel, C.; Wilson, A.; Bianconi, A.; Bragadireanu, M.; Caprini, M.; Pantea, D.; Patel, B.; Czyzycki, W.; Domagala, M.; Filo, G.; Jaworowski, J.; Krawczyk, M.; Lisowski, E.; Lisowski, F.; Michałek, M.; Poznański, P.; Płażek, J.; Korcyl, K.; Kozela, A.; Kulessa, P.; Lebiedowicz, P.; Pysz, K.; Schäfer, W.; Szczurek, A.; Fiutowski, T.; Idzik, M.; Mindur, B.; Przyborowski, D.; Swientek, K.; Biernat, J.; Kamys, B.; Kistryn, S.; Korcyl, G.; Krzemien, W.; Magiera, A.; Moskal, P.; Psyzniak, A.; Rudy, Z.; Salabura, P.; Smyrski, J.; Strzempek, P.; Wronska, A.; Augustin, I.; Böhm, R.; Lehmann, I.; Nicmorus Marinescu, D.; Schmitt, L.; Varentsov, V.; Al-Turany, M.; Belias, A.; Deppe, H.; Dzhygadlo, R.; Ehret, A.; Flemming, H.; Gerhardt, A.; Götzen, K.; Gromliuk, A.; Gruber, L.; Karabowicz, R.; Kliemt, R.; Krebs, M.; Kurilla, U.; Lehmann, D.; Löchner, S.; Lühning, J.; Lynen, U.; Orth, H.; Patsyuk, M.; Peters, K.; Saito, T.; Schepers, G.; Schmidt, C. J.; Schwarz, C.; Schwiening, J.; Täschner, A.; Traxler, M.; Ugur, C.; Voss, B.; Wieczorek, P.; Wilms, A.; Zühlsdorf, M.; Abazov, V. M.; Alexeev, G.; Arefiev, A.; Astakhov, V. I.; Barabanov, M. Yu.; Batyunya, B. V.; Davydov, Yu. I.; Dodokhov, V. Kh.; Efremov, A. A.; Fechtchenko, A.; Fedunov, A. G.; Galoyan, A.; Grigoryan, S.; Koshurnikov, E. K.; Lobanov, V. I.; Lobanov, Y. Yu.; Makarov, A. F.; Malinina, L. V.; Malyshev, V. L.; Olshevskiy, A.; Perevalova, E.; Piskun, A. A.; Pocheptsov, T.; Pontecorvo, G.; Rodionov, V.; Rogov, Y.; Salmin, R.; Samartsev, A.; Sapozhnikov, M. G.; Shabratova, G.; Skachkov, N. B.; Skachkova, A. N.; Strokovsky, E. A.; Suleimanov, M.; Teshev, R.; Tokmenin, V.; Uzhinsky, V.; Vodopyanov, A.; Zaporozhets, S. A.; Zhuravlev, N. I.; Zorin, A. G.; Branford, D.; Glazier, D.; Watts, D.; Böhm, M.; Britting, A.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Dobbs, S.; Seth, K.; Tomaradze, A.; Xiao, T.; Bettoni, D.; Carassiti, V.; Cotta Ramusino, A.; Dalpiaz, P.; Drago, A.; Fioravanti, E.; Garzia, I.; Savriè, M.; Akishina, V.; Kisel, I.; Kozlov, G.; Pugach, M.; Zyzak, M.; Gianotti, P.; Guaraldo, C.; Lucherini, V.; Bersani, A.; Bracco, G.; Macri, M.; Parodi, R. F.; Biguenko, K.; Brinkmann, K.; Di Pietro, V.; Diehl, S.; Dormenev, V.; Drexler, P.; Düren, M.; Etzelmüller, E.; Galuska, M.; Gutz, E.; Hahn, C.; Hayrapetyan, A.; Kesselkaul, M.; Kühn, W.; Kuske, T.; Lange, J. S.; Liang, Y.; Metag, V.; Nanova, M.; Nazarenko, S.; Novotny, R.; Quagli, T.; Reiter, S.; Rieke, J.; Rosenbaum, C.; Schmidt, M.; Schnell, R.; Stenzel, H.; Thöring, U.; Ullrich, M.; Wagner, M. N.; Wasem, T.; Wohlfarth, B.; Zaunick, H.; Ireland, D.; Rosner, G.; Seitz, B.; Deepak, P. N.; Kulkarni, A.; Apostolou, A.; Babai, M.; Kavatsyuk, M.; Lemmens, P.; Lindemulder, M.; Loehner, H.; Messchendorp, J.; Schakel, P.; Smit, H.; Tiemens, M.; van der Weele, J. C.; Veenstra, R.; Vejdani, S.; Dutta, K.; Kalita, K.; Kumar, A.; Roy, A.; Sohlbach, H.; Bai, M.; Bianchi, L.; Büscher, M.; Cao, L.; Cebulla, A.; Dosdall, R.; Gillitzer, A.; Goldenbaum, F.; Grunwald, D.; Herten, A.; Hu, Q.; Kemmerling, G.; Kleines, H.; Lehrach, A.; Nellen, R.; Ohm, H.; Orfanitski, S.; Prasuhn, D.; Prencipe, E.; Pütz, J.; Ritman, J.; Schadmand, S.; Sefzick, T.; Serdyuk, V.; Sterzenbach, G.; Stockmanns, T.; Wintz, P.; Wüstner, P.; Xu, H.; Zambanini, A.; Li, S.; Li, Z.; Sun, Z.; Xu, H.; Rigato, V.; Isaksson, L.; Achenbach, P.; Corell, O.; Denig, A.; Distler, M.; Hoek, M.; Karavdina, A.; Lauth, W.; Liu, Z.; Merkel, H.; Müller, U.; Pochodzalla, J.; Schlimme, S.; Sfienti, C.; Thiel, M.; Ahmadi, H.; Ahmed, S.; Bleser, S.; Capozza, L.; Cardinali, M.; Dbeyssi, A.; Deiseroth, M.; Feldbauer, F.; Fritsch, M.; Fröhlich, B.; Jasinski, P.; Kang, D.; Khaneft, D.; Klasen, R.; Leithoff, H. H.; Lin, D.; Maas, F.; Maldaner, S.; Martìnez Rojo, M.; Marta, M.; Michel, M.; Mora Espì, M. C.; Morales Morales, C.; Motzko, C.; Nerling, F.; Noll, O.; Pflüger, S.; Pitka, A.; Rodríguez Piñeiro, D.; Sanchez Lorente, A.; Steinen, M.; Valente, R.; Weber, T.; Zambrana, M.; Zimmermann, I.; Fedorov, A.; Korjik, M.; Missevitch, O.; Boukharov, A.; Malyshev, O.; Marishev, I.; Balanutsa, P.; Balanutsa, V.; Chernetsky, V.; Demekhin, A.; Dolgolenko, A.; Fedorets, P.; Gerasimov, A.; Goryachev, V.; Chandratre, V.; Datar, V.; Dutta, D.; Jha, V.; Kumawat, H.; Mohanty, A. K.; Parmar, A.; Roy, B.; Sonika, G.; Fritzsch, C.; Grieser, S.; Hergemöller, A. K.; Hetz, B.; Hüsken, N.; Khoukaz, A.; Wessels, J. P.; Khosonthongkee, K.; Kobdaj, C.; Limphirat, A.; Srisawad, P.; Yan, Y.; Barnyakov, M.; Barnyakov, A. Yu.; Beloborodov, K.; Blinov, A. E.; Blinov, V. E.; Bobrovnikov, V. S.; Kononov, S.; Kravchenko, E. A.; Kuyanov, I. A.; Martin, K.; Onuchin, A. P.; Serednyakov, S.; Sokolov, A.; Tikhonov, Y.; Atomssa, E.; Kunne, R.; Marchand, D.; Ramstein, B.; Van de Wiele, J.; Wang, Y.; Boca, G.; Costanza, S.; Genova, P.; Montagna, P.; Rotondi, A.; Abramov, V.; Belikov, N.; Bukreeva, S.; Davidenko, A.; Derevschikov, A.; Goncharenko, Y.; Grishin, V.; Kachanov, V.; Kormilitsin, V.; Levin, A.; Melnik, Y.; Minaev, N.; Mochalov, V.; Morozov, D.; Nogach, L.; Poslavskiy, S.; Ryazantsev, A.; Ryzhikov, S.; Semenov, P.; Shein, I.; Uzunian, A.; Vasiliev, A.; Yakutin, A.; Tomasi-Gustafsson, E.; Roy, U.; Yabsley, B.; Belostotski, S.; Gavrilov, G.; Izotov, A.; Manaenkov, S.; Miklukho, O.; Veretennikov, D.; Zhdanov, A.; Makonyi, K.; Preston, M.; Tegner, P.; Wölbing, D.; Bäck, T.; Cederwall, B.; Rai, A. K.; Godre, S.; Calvo, D.; Coli, S.; De Remigis, P.; Filippi, A.; Giraudo, G.; Lusso, S.; Mazza, G.; Mignone, M.; Rivetti, A.; Wheadon, R.; Balestra, F.; Iazzi, F.; Introzzi, R.; Lavagno, A.; Olave, J.; Amoroso, A.; Bussa, M. P.; Busso, L.; De Mori, F.; Destefanis, M.; Fava, L.; Ferrero, L.; Greco, M.; Hu, J.; Lavezzi, L.; Maggiora, M.; Maniscalco, G.; Marcello, S.; Sosio, S.; Spataro, S.; Birsa, R.; Bradamante, F.; Bressan, A.; Martin, A.; Calen, H.; Ikegami Andersson, W.; Johansson, T.; Kupsc, A.; Marciniewski, P.; Papenbrock, M.; Pettersson, J.; Schönning, K.; Wolke, M.; Galnander, B.; Diaz, J.; Pothodi Chackara, V.; Chlopik, A.; Kesik, G.; Melnychuk, D.; Slowinski, B.; Trzcinski, A.; Wojciechowski, M.; Wronka, S.; Zwieglinski, B.; Bühler, P.; Marton, J.; Steinschaden, D.; Suzuki, K.; Widmann, E.; Zmeskal, J.; Gerl, Jürgen; Kojouharov, Ivan; Kojouharova, Jasmina

    2016-10-01

    Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P ‾ ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ--atoms will be feasible and even the production of Ω--atoms will be within reach. The latter might open the door to the | S | = 3 world in strangeness nuclear physics, by the study of the hadronic Ω--nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions.

  14. Cryogenic exciter

    SciTech Connect

    Bray, James William; Garces, Luis Jose

    2012-03-13

    The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.

  15. On the slow dynamics of near-field acoustically levitated objects under High excitation frequencies

    NASA Astrophysics Data System (ADS)

    Ilssar, Dotan; Bucher, Izhak

    2015-10-01

    This paper introduces a simplified analytical model describing the governing dynamics of near-field acoustically levitated objects. The simplification converts the equation of motion coupled with the partial differential equation of a compressible fluid, into a compact, second order ordinary differential equation, where the local stiffness and damping are transparent. The simplified model allows one to more easily analyse and design near-field acoustic levitation based systems, and it also helps to devise closed-loop controller algorithms for such systems. Near-field acoustic levitation employs fast ultrasonic vibrations of a driving surface and exploits the viscosity and the compressibility of a gaseous medium to achieve average, load carrying pressure. It is demonstrated that the slow dynamics dominates the transient behaviour, while the time-scale associated with the fast, ultrasonic excitation has a small presence in the oscillations of the levitated object. Indeed, the present paper formulates the slow dynamics under an ultrasonic excitation without the need to explicitly consider the latter. The simplified model is compared with a numerical scheme based on Reynolds equation and with experiments, both showing reasonably good results.

  16. Evaluation of a doubly-swept blade tip for rotorcraft noise reduction

    NASA Technical Reports Server (NTRS)

    Wake, Brian E.; Egolf, T. Alan

    1992-01-01

    A computational study was performed for a doubly-swept rotor blade tip to determine its benefit for high-speed impulsive (HSI) and blade-vortex interaction (BVI) noise. This design consists of aft and forward sweep. For the HSI-noise computations, unsteady Euler calculations were performed for several variations to a rotor blade geometry. A doubly-swept planform was predicted to increase the delocalizing Mach number to 0.94 (representative of a 200+ kt helicopter). For the BVI-noise problem, it had been hypothesized that the doubly-swept blade tip, by producing a leading-edge vortex, would reduce the tip-vortex effect on BVI noise. A procedure was used in which the tip vortex velocity profile computed by a Navier-Stokes solver was used to compute the inflow associated with BVI. This inflow was used by a Euler solver to compute the unsteady pressures for an acoustic analysis. The results of this study were inconclusive due to the difficulty in accurately predicting the viscous tip vortex downstream of the blade. Also, for the condition studied, no leading-edge vortex formed at the tip.

  17. Evaluation of a doubly-swept blade tip for rotorcraft noise reduction

    NASA Astrophysics Data System (ADS)

    Wake, Brian E.; Egolf, T. Alan

    1992-10-01

    A computational study was performed for a doubly-swept rotor blade tip to determine its benefit for high-speed impulsive (HSI) and blade-vortex interaction (BVI) noise. This design consists of aft and forward sweep. For the HSI-noise computations, unsteady Euler calculations were performed for several variations to a rotor blade geometry. A doubly-swept planform was predicted to increase the delocalizing Mach number to 0.94 (representative of a 200+ kt helicopter). For the BVI-noise problem, it had been hypothesized that the doubly-swept blade tip, by producing a leading-edge vortex, would reduce the tip-vortex effect on BVI noise. A procedure was used in which the tip vortex velocity profile computed by a Navier-Stokes solver was used to compute the inflow associated with BVI. This inflow was used by a Euler solver to compute the unsteady pressures for an acoustic analysis. The results of this study were inconclusive due to the difficulty in accurately predicting the viscous tip vortex downstream of the blade. Also, for the condition studied, no leading-edge vortex formed at the tip.

  18. Ensemble density functional theory method correctly describes bond dissociation, excited state electron transfer, and double excitations

    SciTech Connect

    Filatov, Michael; Huix-Rotllant, Miquel; Burghardt, Irene

    2015-05-14

    State-averaged (SA) variants of the spin-restricted ensemble-referenced Kohn-Sham (REKS) method, SA-REKS and state-interaction (SI)-SA-REKS, implement ensemble density functional theory for variationally obtaining excitation energies of molecular systems. In this work, the currently existing version of the SA-REKS method, which included only one excited state into the ensemble averaging, is extended by adding more excited states to the averaged energy functional. A general strategy for extension of the REKS-type methods to larger ensembles of ground and excited states is outlined and implemented in extended versions of the SA-REKS and SI-SA-REKS methods. The newly developed methods are tested in the calculation of several excited states of ground-state multi-reference systems, such as dissociating hydrogen molecule, and excited states of donor–acceptor molecular systems. For hydrogen molecule, the new method correctly reproduces the distance dependence of the lowest excited state energies and describes an avoided crossing between the doubly excited and singly excited states. For bithiophene–perylenediimide stacked complex, the SI-SA-REKS method correctly describes crossing between the locally excited state and the charge transfer excited state and yields vertical excitation energies in good agreement with the ab initio wavefunction methods.

  19. Ensemble density functional theory method correctly describes bond dissociation, excited state electron transfer, and double excitations.

    PubMed

    Filatov, Michael; Huix-Rotllant, Miquel; Burghardt, Irene

    2015-05-14

    State-averaged (SA) variants of the spin-restricted ensemble-referenced Kohn-Sham (REKS) method, SA-REKS and state-interaction (SI)-SA-REKS, implement ensemble density functional theory for variationally obtaining excitation energies of molecular systems. In this work, the currently existing version of the SA-REKS method, which included only one excited state into the ensemble averaging, is extended by adding more excited states to the averaged energy functional. A general strategy for extension of the REKS-type methods to larger ensembles of ground and excited states is outlined and implemented in extended versions of the SA-REKS and SI-SA-REKS methods. The newly developed methods are tested in the calculation of several excited states of ground-state multi-reference systems, such as dissociating hydrogen molecule, and excited states of donor-acceptor molecular systems. For hydrogen molecule, the new method correctly reproduces the distance dependence of the lowest excited state energies and describes an avoided crossing between the doubly excited and singly excited states. For bithiophene-perylenediimide stacked complex, the SI-SA-REKS method correctly describes crossing between the locally excited state and the charge transfer excited state and yields vertical excitation energies in good agreement with the ab initio wavefunction methods.

  20. Ground and excited state properties of high performance anthocyanidin dyes-sensitized solar cells in the basic solutions

    SciTech Connect

    Prima, Eka Cahya; Yuliarto, Brian; Suyatman; Dipojono, Hermawan Kresno

    2015-09-30

    The aglycones of anthocyanidin dyes were previously reported to form carbinol pseudobase, cis-chalcone, and trans-chalcone due to the basic levels. The further investigations of ground and excited state properties of the dyes were characterized using density functional theory with PCM(UFF)/B3LYP/6-31+G(d,p) level in the basic solutions. However, to the best of our knowledge, the theoretical investigation of their potential photosensitizers has never been reported before. In this paper, the theoretical photovoltaic properties sensitized by dyes have been successfully investigated including the electron injections, the ground and excited state oxidation potentials, the estimated open circuit voltages, and the light harvesting efficiencies. The results prove that the electronic properties represented by dyes’ LUMO-HOMO levels will affect to the photovoltaic performances. Cis-chalcone dye is the best anthocyanidin aglycone dye with the electron injection spontaneity of −1.208 eV, the theoretical open circuit voltage of 1.781 V, and light harvesting efficiency of 56.55% due to the best HOMO-LUMO levels. Moreover, the ethanol solvent slightly contributes to the better cell performance than the water solvent dye because of the better oxidation potential stabilization in the ground state as well as in the excited state. These results are in good agreement with the known experimental report that the aglycones of anthocyanidin dyes in basic solvent are the high potential photosensitizers for dye-sensitized solar cell.

  1. Dipole moments of HDO in highly excited vibrational states measured by Stark induced photofragment quantum beat spectroscopy.

    PubMed

    Theulé, Patrice; Callegari, Andrea; Rizzo, Thomas R; Muenter, John S

    2005-03-22

    We report here a measurement of electric dipole moments in highly vibrationally excited HDO molecules. We use photofragment yield detected quantum beat spectroscopy to determine electric field induced splittings of the J=1 rotational levels of HDO excited with 4, 5, and 8 quanta of vibration in the OH stretching mode. The splittings allow us to deduce mua and mub, the projections of dipole moment onto the molecular rotation inertial axes. We compare the measured HDO dipole moment components with the results of quantitative calculations based on Morse oscillator wave functions and an ab initio dipole moment surface. The vibrational dependence of the dipole moment components reflect both structural and electronic changes in HDO upon vibrational excitation; principally the vibrational dependence of the O-H bond length and bond angle, and the resulting change in orientation of the principal inertial coordinate system. The dipole moment data also provide a sensitive test of theoretical dipole moment and potential energy surfaces, particularly for molecular configurations far from equilibrium.

  2. Ground and excited state properties of high performance anthocyanidin dyes-sensitized solar cells in the basic solutions

    NASA Astrophysics Data System (ADS)

    Prima, Eka Cahya; Yuliarto, Brian; Suyatman, Dipojono, Hermawan Kresno

    2015-09-01

    The aglycones of anthocyanidin dyes were previously reported to form carbinol pseudobase, cis-chalcone, and trans-chalcone due to the basic levels. The further investigations of ground and excited state properties of the dyes were characterized using density functional theory with PCM(UFF)/B3LYP/6-31+G(d,p) level in the basic solutions. However, to the best of our knowledge, the theoretical investigation of their potential photosensitizers has never been reported before. In this paper, the theoretical photovoltaic properties sensitized by dyes have been successfully investigated including the electron injections, the ground and excited state oxidation potentials, the estimated open circuit voltages, and the light harvesting efficiencies. The results prove that the electronic properties represented by dyes' LUMO-HOMO levels will affect to the photovoltaic performances. Cis-chalcone dye is the best anthocyanidin aglycone dye with the electron injection spontaneity of -1.208 eV, the theoretical open circuit voltage of 1.781 V, and light harvesting efficiency of 56.55% due to the best HOMO-LUMO levels. Moreover, the ethanol solvent slightly contributes to the better cell performance than the water solvent dye because of the better oxidation potential stabilization in the ground state as well as in the excited state. These results are in good agreement with the known experimental report that the aglycones of anthocyanidin dyes in basic solvent are the high potential photosensitizers for dye-sensitized solar cell.

  3. Comparison of atmospheric air plasmas excited by high-voltage nanosecond pulsed discharge and sinusoidal alternating current discharge

    NASA Astrophysics Data System (ADS)

    Zhang, Shuai; Wang, Wen-chun; Jiang, Peng-chao; Yang, De-zheng; Jia, Li; Wang, Sen

    2013-10-01

    In this paper, atmospheric pressure air discharge plasma in quartz tube is excited by 15 ns high-voltage nanosecond pulsed discharge (HVNPD) and sinusoidal alternating current discharge (SACD), respectively, and a comparison study of these two kinds of discharges is made through visual imaging, electrical characterization, optical detection of active species, and plasma gas temperature. The peak voltage of the power supplies is kept at 16 kV while the pulse repetition rate of nanosecond pulse power supply is 100 Hz, and the frequency of sinusoidal power supply is 10 kHz. Results show that the HVNPD is uniform while the SACD presents filamentary mode. For exciting the same cycles of discharge, the average energy consumption in HVNPD is about 1/13 of the SACD. However, the chemical active species generated by the HVNPD is about 2-9 times than that excited by the SACD. Meanwhile, the rotational and vibrational temperatures have been obtained via fitting the simulated spectrum of N2 (C3Πu → B3Πg, 0-2) with the measured one, and the results show that the plasma gas temperature in the HVNPD remains close to room temperature whereas the plasma gas temperature in the SACD is about 200 K higher than that in HVNPD in the initial phase and continually increases as discharge exposure time goes on.

  4. Exposure to a high fat diet during the perinatal period alters vagal motoneurone excitability, even in the absence of obesity

    PubMed Central

    Bhagat, Ruchi; Fortna, Samuel R; Browning, Kirsteen N

    2015-01-01

    The perinatal period is critically important to the development of autonomic neural circuits responsible for energy homeostasis. Vagal neurocircuits are vital to the regulation of upper gastrointestinal functions, including satiety. Diet-induced obesity modulates the excitability and responsiveness of both peripheral vagal afferents and central vagal efferents but less information is available regarding the effects of diet per se on vagal neurocircuit functions. The aims of this study were to investigate whether perinatal exposure to a high fat diet (HFD) dysregulated dorsal motor nucleus of the vagus (DMV) neurones, prior to the development of obesity. Whole cell patch clamp recordings were made from gastric-projecting DMV neurones in thin brainstem slices from rats that were exposed to either a control diet or HFD from pregnancy day 13. Our data demonstrate that following perinatal HFD: (i) DMV neurones had decreased excitability and input resistance with a reduced ability to fire action potentials; (ii) the proportion of DMV neurones excited by cholecystokinin (CCK) was unaltered but the proportion of neurones in which CCK increased excitatory glutamatergic synaptic inputs was reduced; (iii) the tonic activation of presynaptic group II metabotropic glutamate receptors on inhibitory nerve terminals was attenuated, allowing modulation of GABAergic synaptic transmission; and (iv) the size and dendritic arborization of gastric-projecting DMV neurones was increased. These results suggest that perinatal HFD exposure compromises the excitability and responsiveness of gastric-projecting DMV neurones, even in the absence of obesity, suggesting that attenuation of vago-vagal reflex signalling may precede the development of obesity. PMID:25556801

  5. Decay out of the yrast and excited highly-deformed bands in the even-even nucleus {sup 134}Nd

    SciTech Connect

    Petrache, C.M.; Bazzacco, D.; Lunardi, S.

    1996-12-31

    The resolving power achieved by the new generation of {gamma}-ray detector arrays allows now to observe transitions with intensities of the order of {approximately}10{sup {minus}3} of the population of the final residual nucleus, making therefore feasible the study of the very weakly populated excited bands built on the superdeformed (SD) minimum or of the decay out of the SD bands. As a matter of fact, numerous excited SD bands have been observed in the different regions of superdeformation, which led to a deeper understanding of the single-particle excitation in the second minimum. The first experimental breakthrough in the study of the decay out process has been achieved in the odd-even {sup 133,135}Nd nuclei of the A=130 mass region. There, the observation of the discrete linking transitions has been favored by the relatively higher intensity of the highly-deformed (HD) bands ({approximately}10%), as well as by the small excitation energy with respect to the yrast line in the decay-out region ({approximately}1 MeV). No discrete linking transitions have been so far observed in the A=80, 150 mass regions. The present results suggest that the decay out of the HD bands in {sup 134}Nd is triggered by the crossing with the N=4 [402]5/2{sup +} Nilsson orbital, that has a smaller deformation than the corresponding N=6 intruder configuration. The crossing favours the mixing with the ND rotational bands strongly enhancing the decay-out process and weakening the in-band transition strength. The HD band becomes fragmented and looses part of its character. The intensity of the decay-out transitions increases when the spin of the HD state decreases, indicating enhanced ND amplitude in the wavefunction when going down the band. Lifetime measurements of the HD bands are crucial to further elucidate the decay-out process.

  6. Highly specific label-free molecular imaging with spectrally tailored excitation-stimulated Raman scattering (STE-SRS) microscopy

    NASA Astrophysics Data System (ADS)

    Freudiger, Christian W.; Min, Wei; Holtom, Gary R.; Xu, Bingwei; Dantus, Marcos; Sunney Xie, X.

    2011-02-01

    Label-free microscopy that has chemical contrast and high acquisition speeds up to video rates has recently been made possible using stimulated Raman scattering (SRS) microscopy. SRS imaging offers high sensitivity, but the spectral specificity of the original narrowband implementation is limited, making it difficult to distinguish chemical species with overlapping Raman bands. Here, we present a highly specific imaging method that allows mapping of a particular chemical species in the presence of interfering species, based on tailored multiplex excitation of its vibrational spectrum. This is implemented by spectral modulation of a broadband pump beam at a high frequency (>1 MHz), allowing detection of the SRS signal of the narrowband Stokes beam with high sensitivity. Using the scheme, we demonstrate quantification of cholesterol in the presence of lipids, and real-time three-dimensional spectral imaging of protein, stearic acid and oleic acid in live Caenorhabditis elegans.

  7. Fragmentation network of doubly charged methionine: Interpretation using graph theory

    NASA Astrophysics Data System (ADS)

    Ha, D. T.; Yamazaki, K.; Wang, Y.; Alcamí, M.; Maeda, S.; Kono, H.; Martín, F.; Kukk, E.

    2016-09-01

    The fragmentation of doubly charged gas-phase methionine (HO2CCH(NH2)CH2CH2SCH3) is systematically studied using the self-consistent charge density functional tight-binding molecular dynamics (MD) simulation method. We applied graph theory to analyze the large number of the calculated MD trajectories, which appears to be a highly effective and convenient means of extracting versatile information from the large data. The present theoretical results strongly concur with the earlier studied experimental ones. Essentially, the dication dissociates into acidic group CO2H and basic group C4NSH10. The former may carry a single or no charge and stays intact in most cases, whereas the latter may hold either a single or a double charge and tends to dissociate into smaller fragments. The decay of the basic group is observed to follow the Arrhenius law. The dissociation pathways to CO2H and C4NSH10 and subsequent fragmentations are also supported by ab initio calculations.

  8. Fragmentation network of doubly charged methionine: Interpretation using graph theory.

    PubMed

    Ha, D T; Yamazaki, K; Wang, Y; Alcamí, M; Maeda, S; Kono, H; Martín, F; Kukk, E

    2016-09-01

    The fragmentation of doubly charged gas-phase methionine (HO2CCH(NH2)CH2CH2SCH3) is systematically studied using the self-consistent charge density functional tight-binding molecular dynamics (MD) simulation method. We applied graph theory to analyze the large number of the calculated MD trajectories, which appears to be a highly effective and convenient means of extracting versatile information from the large data. The present theoretical results strongly concur with the earlier studied experimental ones. Essentially, the dication dissociates into acidic group CO2H and basic group C4NSH10. The former may carry a single or no charge and stays intact in most cases, whereas the latter may hold either a single or a double charge and tends to dissociate into smaller fragments. The decay of the basic group is observed to follow the Arrhenius law. The dissociation pathways to CO2H and C4NSH10 and subsequent fragmentations are also supported by ab initio calculations. PMID:27608997

  9. 60-GHz integrated-circuit high data rate quadriphase shift keying exciter and modulator

    NASA Technical Reports Server (NTRS)

    Grote, A.; Chang, K.

    1984-01-01

    An integrated-circuit quadriphase shift keying (QPSK) exciter and modulator have demonstrated excellent performance directly modulating a carrier frequency of 60 GHz with an output phase error of less than 3 degrees and maximum amplitude error of 0.5 dB. The circuit consists of a 60-GHz Gunn VCO phase-locked to a low-frequency reference source, a 4th subharmonic mixer, and a QPSK modlator packaged into a small volume of 1.8 x 2.5 x 0.35 in. The use of microstrip has the advantages of small size, light-weight, and low-cost fabrication. The unit has the potential for multigigabit data rate applications.

  10. The FERRUM project: Experimental transition probabilities from highly excited even 5s levels in Cr ii

    NASA Astrophysics Data System (ADS)

    Engström, L.; Lundberg, H.; Nilsson, H.; Hartman, H.; Bäckström, E.

    2014-10-01

    We report lifetime measurements of the five levels in the 3d4(a5D)5s e6D term in Cr ii at an energy around 83 000 cm-1, and log(gf) values for 38 transitions from the investigated levels. The lifetimes are obtained using time-resolved, laser-induced fluorescence on ions from a laser-produced plasma. Since the levels have the same parity as the low-lying states directly populated in the plasma, we used a two-photon excitation scheme. This process is greatly facilitated by the presence of the 3d4(a5D)4p z6F levels at roughly half the energy difference. The f-values are obtained by combining the experimental lifetimes with branching fractions derived using relative intensities from a hollow cathode lamp recorded with a Fourier transform spectrometer.

  11. Carbon dioxide ion dissociations after inner shell excitation and ionization: The origin of site-specific effects

    SciTech Connect

    Eland, J. H. D.; Zagorodskikh, S.; Mucke, M.; Squibb, R. J.; Feifel, R.; Sorensen, S. L.

    2014-05-14

    Multi-coincidence experiments with detection of both electrons and ions from decay of core-excited and core-ionized states of CO{sub 2} confirm that O{sub 2}{sup +} is formed specifically in Auger decay from the C1s-π* and O1s-π* resonances. Molecular rearrangement occurs by bending in the resonant states, and O{sub 2}{sup +} is produced by both single and double Auger decay. It is suggested that electron capture by C{sup +} after partial dissociation in the doubly ionized core of excited CO{sub 2}{sup +}, formed by shake-up in spectator resonant Auger decay, accounts for high kinetic energy and high internal energy in some C + O{sub 2}{sup +} fragments.

  12. Dynamics of self-excited thermoacoustic instability in a combustion system: Pseudo-periodic and high-dimensional nature.

    PubMed

    Okuno, Yuta; Small, Michael; Gotoda, Hiroshi

    2015-04-01

    We have examined the dynamics of self-excited thermoacoustic instability in a fundamentally and practically important gas-turbine model combustion system on the basis of complex network approaches. We have incorporated sophisticated complex networks consisting of cycle networks and phase space networks, neither of which has been considered in the areas of combustion physics and science. Pseudo-periodicity and high-dimensionality exist in the dynamics of thermoacoustic instability, including the possible presence of a clear power-law distribution and small-world-like nature.

  13. Dynamics of self-excited thermoacoustic instability in a combustion system: Pseudo-periodic and high-dimensional nature.

    PubMed

    Okuno, Yuta; Small, Michael; Gotoda, Hiroshi

    2015-04-01

    We have examined the dynamics of self-excited thermoacoustic instability in a fundamentally and practically important gas-turbine model combustion system on the basis of complex network approaches. We have incorporated sophisticated complex networks consisting of cycle networks and phase space networks, neither of which has been considered in the areas of combustion physics and science. Pseudo-periodicity and high-dimensionality exist in the dynamics of thermoacoustic instability, including the possible presence of a clear power-law distribution and small-world-like nature. PMID:25933655

  14. ATOMIC AND MOLECULAR PHYSICS: High Accuracy Calculation for Excited-State Energies of H Atoms in a Magnetic Field

    NASA Astrophysics Data System (ADS)

    Zhao, Li-Bo; Du, Meng-Li

    2009-08-01

    Using the recently developed finite-basis-set method with B splines, excited states of H atoms in a magnetic field have been calculated. Energy levels are presented for the ten excited states, 2s0, 3d'0, 3p0, 3p-1, 3d-1, 4d-1, 3d-2, 4d-2, 4f-2, and 5f-2 as a function of magnetic field strengths with a range from zero up to 2.35 × 106 T. The obtained results are compared with available high accuracy theoretical data reported in the literature and found to be in excellent agreement. The comparison also shows that the current method can produce energy levels with an accuracy higher than the existing high accuracy method [Phys. Rev. A 54 (1996) 287]. Here high accuracy energy levels are for the first time reported for the 3d'0, 4d-1, 4d-2, 4f-2, and 5f-2 states.

  15. Field evaporation of doubly charged ions from a polar liquid

    NASA Astrophysics Data System (ADS)

    Balakin, A. A.; Novikova, L. I.

    2012-11-01

    The effect of charge on field evaporation of ions from polar liquids is considered. Using the electromembrane ion source, we performed mass-spectral analysis of field evaporation of ions from the solution of sodium sulfate in a water-glycerol mixture. The composition of doubly charged cluster ions in the field evaporation from glycerol is determined. The rates of the field evaporation of doubly charged ions and singly charged ions are compared. It is shown that the ion charge as well as its localization considerably influences the efficiency of field evaporation of ions from polar liquids.

  16. Measurement of Doubly Charged Ions in Ion Thruster Plumes

    NASA Technical Reports Server (NTRS)

    Williams, George J., Jr.; Domonkos, Matthew T.; Chavez, Joy M.

    2002-01-01

    The ratio of doubly to singly charged ions was measured in the plumes of a 30 cm and of a 40 cm ion thruster. The measured ratio was correlated with observed erosion rates and thruster operating conditions. The measured and calculated erosion rates paralleled variation in the j(sup ++)/j(sup +) ratio and indicated that the erosion was dominated by Xe III. Simple models of cathode potential surfaces which were developed in support of this work were in agreement with this conclusion and provided a predictive capability of the erosion given the ratio of doubly to singly charged ion currents.

  17. Search for doubly charged Higgs bosons at LEP2

    NASA Astrophysics Data System (ADS)

    Abdallah, J.; Abreu, P.; Adam, W.; Adzic, P.; Albrecht, T.; Alderweireld, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P. P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W.-D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J. E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K.-H.; Begalli, M.; Behrmann, A.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P. S. L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T. J. V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J. M.; Bugge, L.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N.; Cavallo, F.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Chung, S. U.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M. J.; Crawley, B.; Crennell, D.; Cuevas, J.; D'Hondt, J.; Dalmau, J.; da Silva, T.; da Silva, W.; Della Ricca, G.; de Angelis, A.; de Boer, W.; de Clercq, C.; de Lotto, B.; de Maria, N.; de Min, A.; de Paula, L.; di Ciaccio, L.; di Simone, A.; Doroba, K.; Drees, J.; Dris, M.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M. C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, Ph.; Gazis, E.; Geralis, T.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Hansen, J.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S.-O.; Holt, P. J.; Houlden, M. A.; Hultqvist, K.; Jackson, J. N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, E. K.; Johansson, P. D.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B. P.; Kiiskinen, A.; King, B. T.; Kjaer, N. J.; Kluit, P.; Kokkinias, P.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J. H.; Lopez, J. M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J.-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Mc Nulty, R.; Meroni, C.; Meyer, W. T.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Moenig, K.; Monge, R.; Montenegro, J.; Moraes, D.; Moreno, S.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nicolaidou, R.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J. P.; Palka, H.; Papadopoulou, Th. D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Peralta, L.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Piotto, E.; Podobnik, T.; Poireau, V.; Pol, M. E.; Polok, G.; Poropat, P.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Rames, J.; Ramler, L.; Read, A.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Rosenberg, E.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Savoy-Navarro, A.; Schwickerath, U.; Segar, A.; Sekulin, R.; Siebel, M.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A. C.; Tegenfeldt, F.; Timmermans, J.; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tomaradze, A.; Tome, B.; Tonazzo, A.; Tortosa, P.; Travnicek, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M.-L.; Tyapkin, I. A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; van Dam, P.; van Eldik, J.; van Lysebetten, A.; van Remortel, N.; van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verbeure, F.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A. J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zimin, N. I.; Zintchenko, A.; Zupan, M.; Delphi Collaboration

    2003-01-01

    A search for pair-produced doubly charged Higgs bosons has been performed using the data collected by the DELPHI detector at LEP at centre-of-mass energies between 189 and 209 GeV. No excess is observed in the data with respect to the Standard Model background. A lower limit for the mass of 97.3 GeV/c2 at the 95% confidence level has been set for doubly charged Higgs bosons in left-right symmetric models for any value of the Yukawa coupling between the Higgs bosons and the τ leptons.

  18. Search for doubly charged Higgs bosons at LEP2

    NASA Astrophysics Data System (ADS)

    DELPHI Collaboration; Abdallah, J.; Abreu, P.; Adam, W.; Adzic, P.; Albrecht, T.; Alderweireld, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P. P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W.-D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J. E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K.-H.; Begalli, M.; Behrmann, A.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P. S. L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T. J. V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J. M.; Bugge, L.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N.; Cavallo, F.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Chung, S. U.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M. J.; Crawley, B.; Crennell, D.; Cuevas, J.; D'Hondt, J.; Dalmau, J.; da Silva, T.; da Silva, W.; della Ricca, G.; de Angelis, A.; de Boer, W.; de Clercq, C.; de Lotto, B.; de Maria, N.; de Min, A.; de Paula, L.; di Ciaccio, L.; di Simone, A.; Doroba, K.; Drees, J.; Dris, M.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M. C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, Ph.; Gazis, E.; Geralis, T.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Hansen, J.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S.-O.; Holt, P. J.; Houlden, M. A.; Hultqvist, K.; Jackson, J. N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, E. K.; Johansson, P. D.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B. P.; Kiiskinen, A.; King, B. T.; Kjaer, N. J.; Kluit, P.; Kokkinias, P.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J. H.; Lopez, J. M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J.-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Mc Nulty, R.; Meroni, C.; Meyer, W. T.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Moenig, K.; Monge, R.; Montenegro, J.; Moraes, D.; Moreno, S.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nicolaidou, R.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J. P.; Palka, H.; Papadopoulou, Th. D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Peralta, L.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Piotto, E.; Podobnik, T.; Poireau, V.; Pol, M. E.; Polok, G.; Poropat, P.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Rames, J.; Ramler, L.; Read, A.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Rosenberg, E.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Savoy-Navarro, A.; Schwickerath, U.; Segar, A.; Sekulin, R.; Siebel, M.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A. C.; Tegenfeldt, F.; Timmermans, J.; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tomaradze, A.; Tome, B.; Tonazzo, A.; Tortosa, P.; Travnicek, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M.-L.; Tyapkin, I. A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; van Dam, P.; van Eldik, J.; van Lysebetten, A.; van Remortel, N.; van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verbeure, F.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A. J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zimin, N. I.; Zintchenko, A.; Zupan, M.

    2003-01-01

    A search for pair-produced doubly charged Higgs bosons has been performed using the data collected by the DELPHI detector at LEP at centre-of-mass energies between 189 and 209 GeV. No excess is observed in the data with respect to the Standard Model background. A lower limit for the mass of 97.3 GeV/c2 at the 95% confidence level has been set for doubly charged Higgs bosons in left-right symmetric models for any value of the Yukawa coupling between the Higgs bosons and the /τ leptons.

  19. A mathematical model for the doubly fed wound rotor generator

    NASA Technical Reports Server (NTRS)

    Brady, F. J.

    1983-01-01

    A mathematical analysis of a doubly-fed wound rotor machine used as a constant frequency generator is presented. The purpose of this analysis is to derive a consistent set of circuit equations which produce constant stator frequency and constant stator voltage. Starting with instantaneous circuit equations, the necessary rotor voltages and currents are derived. The model, thus obtained, is assumed to be valid, since the resulting relationships between mechanical power and active volt-amperes agrees with the results of others. In addition, the model allows for a new interpretation of the power flow in the doubly-fed generator.

  20. Oscillator strengths for high-excitation Ti II from laboratory measurements and calculations

    NASA Astrophysics Data System (ADS)

    Lundberg, H.; Hartman, H.; Engström, L.; Nilsson, H.; Persson, A.; Palmeri, P.; Quinet, P.; Fivet, V.; Malcheva, G.; Blagoev, K.

    2016-07-01

    This work reports new experimental radiative lifetimes of six 3d2(3F)5s levels in singly ionized titanium, with an energy around 63 000 cm-1 and four 3d2(3F)4p odd parity levels where we confirm previous investigations. Combining the new 5s lifetimes with branching fractions measured previously by Pickering et al., we report 57 experimental log gf values for transitions from the 5s levels. The lifetime measurements are performed using time-resolved laser-induced fluorescence on ions produced by laser ablation. One- and two-step photon excitation is employed to reach the 4p and 5s levels, respectively. Theoretical calculations of the radiative lifetimes of the measured levels as well as of oscillator strengths for 3336 transitions from these levels are reported. The calculations are carried out by a pseudo-relativistic Hartree-Fock method taking into account core-polarization effects. The theoretical results are in a good agreement with the experiments and are needed for accurate abundance determinations in astronomical objects.

  1. The radiation performance of offset reflector antennas with horn feeds excited by high order modes

    NASA Astrophysics Data System (ADS)

    Thielen, Herbert

    1988-07-01

    The physical reasons for alignment errors in the antenna tracking of asymmetric reflector systems were investigated. The radiation behavior of offset reflector antennas, employing higher-order modes was theoretically and experimentally analyzed. In the case of TE21-mode excitation, a cross-polarization component is produced in single-reflector antennas due to feed tilt which is considerably larger than with the communication mode (TE11 or HE11 mode). In the case of circular polarization, this causes a null shift amounting to 1/10 or 1/5 of the half-power beam width of the main lobe. No null shift exists for the TM01- and TE01-modes. When the TE21-mode is used, the cross-polarization component is considerably smaller for dual-offset than for single-reflector antennas. In the case of ground station antennas where beam-waveguides consisting of two reflectors are used, a similar performance is obtained as for single-reflector antennas.

  2. Observations and theoretical analysis of highly excited singlet and triplet states of cadmium

    NASA Astrophysics Data System (ADS)

    Vidolova-Angelova, E.; Baharis, C.; Roupakas, G.; Kompitsas, M.

    1996-06-01

    We have recorded the 0953-4075/29/12/010/img7 - 50) bound Rydberg spectrum of cadmium. We have fully resolved the multiplet up to n = 19 and partially up to n = 24. Furthermore, we have observed the odd singlet and triplet 5sn f Rydberg series for n = 10 - 22 and n = 4 - 21, respectively. We have applied two- and three-step laser schemes to excite Cd vapour in a heat pipe-like oven which was operated as a thermionic diode for detection. Theoretical calculations were performed for the energies of the 5sn p and 5sn f series using perturbation theory with a zero-order model approximation. There is a good agreement between theoretical and experimental results for the 5sn p series, the deviation decreasing with n and being 1 - 2 0953-4075/29/12/010/img8 for n = 50. The agreement for the 5sn f is satisfactory. From the quantum defect of the 5sn f series we approximate a value of the effective dipole polarizability of the 0953-4075/29/12/010/img9 ion of 0953-4075/29/12/010/img10 in units of the Bohr radius.

  3. Graphene-mediated microfluidic transport and nebulization via high frequency Rayleigh wave substrate excitation.

    PubMed

    Ang, Kar M; Yeo, Leslie Y; Hung, Yew M; Tan, Ming K

    2016-09-21

    The deposition of a thin graphene film atop a chip scale piezoelectric substrate on which surface acoustic waves are excited is observed to enhance its performance for fluid transport and manipulation considerably, which can be exploited to achieve further efficiency gains in these devices. Such gains can then enable complete integration and miniaturization for true portability for a variety of microfluidic applications across drug delivery, biosensing and point-of-care diagnostics, among others, where field-use, point-of-collection or point-of-care functionality is desired. In addition to a first demonstration of vibration-induced molecular transport in graphene films, we show that the coupling of the surface acoustic wave gives rise to antisymmetric Lamb waves in the film which enhance molecular diffusion and hence the flow through the interstitial layers that make up the film. Above a critical input power, the strong substrate vibration displacement can also force the molecules out of the graphene film to form a thin fluid layer, which subsequently destabilizes and breaks up to form a mist of micron dimension aerosol droplets. We provide physical insight into this coupling through a simple numerical model, verified through experiments, and show several-fold improvement in the rate of fluid transport through the film, and up to 55% enhancement in the rate of fluid atomization from the film using this simple method. PMID:27502324

  4. ATOMIC AND MOLECULAR PHYSICS: High order correlation-polarization potential for vibrational excitation scattering of diatomic molecules by low-energy electrons

    NASA Astrophysics Data System (ADS)

    Feng, Hao; Sun, Wei-Guo; Zeng, Yang-Yang

    2009-11-01

    This paper introduces a correlation-polarization potential with high order terms for vibrational excitation in electron-molecule scattering. The new polarization potential generalizes the two-term approximation so that it can better reflect the dependence of correlation and polarization effects on the position coordinate of the scattering electron. It applies the new potential on the vibrational excitation scattering from N2 in an energy range which includes the 2Πg shape resonance. The good agreement of theoretical resonant peaks with experiments shows that polarization potentials with high order terms are important and should be included in vibrational excitation scattering.

  5. Production of excited atomic hydrogen and deuterium from H2 and D2photodissociation

    SciTech Connect

    Bozek, J.D.; Furst, J.E.; Gay, T.J.; Gould, H.; Kilcoyne, A.L.D.; Machacek, J.R.; Martin, F.; McLaughlin, K.W.; Sanz-Vicario, J.L.

    2006-09-17

    We have measured the production of both Ly alpha and H alphafluorescence from atomic H and D for the photodissociation of H2 and D2by linearly polarized photons with energies between 24 and 60 eV. In thisenergy range, excited photofragments result primarily from the productionof doubly excited molecular species which promptly autoionize ordissociate into two neutrals. Our data are compared with ab initiocalculations of the dissociation process, in which both doubly excitedstate production and prompt ionization (nonresonant) channels areconsidered. Agreement between our experimental data and that of earlierwork, and with our theoretical calculations, is qualitative atbest.

  6. Variational study on the vibrational level structure and vibrational level mixing of highly vibrationally excited S₀ D₂CO.

    PubMed

    Rashev, Svetoslav; Moule, David C; Rashev, Vladimir

    2012-11-01

    We perform converged high precision variational calculations to determine the frequencies of a large number of vibrational levels in S(0) D(2)CO, extending from low to very high excess vibrational energies. For the calculations we use our specific vibrational method (recently employed for studies on H(2)CO), consisting of a combination of a search/selection algorithm and a Lanczos iteration procedure. Using the same method we perform large scale converged calculations on the vibrational level spectral structure and fragmentation at selected highly excited overtone states, up to excess vibrational energies of ∼17,000 cm(-1), in order to study the characteristics of intramolecular vibrational redistribution (IVR), vibrational level density and mode selectivity. PMID:22750345

  7. High-frequency vibration energy harvesting from impulsive excitation utilizing intentional dynamic instability caused by strong nonlinearity

    NASA Astrophysics Data System (ADS)

    Remick, Kevin; Dane Quinn, D.; Michael McFarland, D.; Bergman, Lawrence; Vakakis, Alexander

    2016-05-01

    The authors investigate a vibration-based energy harvesting system utilizing essential (nonlinearizable) nonlinearities and electromagnetic coupling elements. The system consists of a grounded, weakly damped linear oscillator (primary system) subjected to a single impulsive load. This primary system is coupled to a lightweight, damped oscillating attachment (denoted as nonlinear energy sink, NES) via a neodymium magnet and an inductance coil, and a piano wire, which generates an essential geometric cubic stiffness nonlinearity. Under impulsive input, the transient damped dynamics of this system exhibit transient resonance captures (TRCs) causing intentional large-amplitude and high-frequency instabilities in the response of the NES. These TRCs result in strong energy transfer from the directly excited primary system to the light-weight attachment. The energy is harvested by the electromagnetic elements in the coupling and, in the present case, dissipated in a resistive element in the electrical circuit. The primary goal of this work is to numerically, analytically, and experimentally demonstrate the efficacy of employing this type of intentional high-frequency dynamic instability to achieve enhanced vibration energy harvesting under impulsive excitation.

  8. Extraction of the vibrational dynamics from the spectra of highly excited molecules and periodic orbit quantization by harmonic inversion

    NASA Astrophysics Data System (ADS)

    Atilgan, Erdinc

    Part I. The effective spectroscopic Hamiltonian fitted to experiment by Troellsch and Temps {A. Troellsch, F. Temps Zeitschrift fuer Physikalische Chemie 215, 207, (2001)} and describing high vibrational excitation to bound and resonant states, is used in conjunction with methods of nonlinear classical dynamics and semiclassical mechanics to extract for all the observed highly excited resonance levels in Polyad 8, the molecular motions upon which they are quantized. Two types of interlaced dynamically distinct ladders of states are revealed. The rungs of these ladders intersperse making the spectra complex. The resonant 2:2:1 frequency ratio of the DC, CO stretches and the bend respectively is what causes the complexity and is what caused past attempts at interpretation to be at best incomplete. All states are assigned with physically meaningful quantum numbers corresponding to quasiconserved quantities. Most interestingly it is pointed out that much of the information and assignment can be done without any calculations at all, using only the qualitative ideas from nonlinear, semiclassical and quantum mechanics along with the information supplied by the experimentalist. Part II. In systems with few degrees of freedom modern quantum calculations are, in general, numerically more efficient than semiclassical methods. However, this situation can be reversed with increasing dimension of the problem. For a three-dimensional system, viz. the hyperbolic four-sphere scattering system, we demonstrate the superiority of semiclassical versus quantum calculations. Semiclassical resonances can easily be obtained even in energy regions which are unattainable with the currently available quantum techniques.

  9. A pilot study on effects of 4×1 high-definition tDCS on motor cortex excitability.

    PubMed

    Caparelli-Daquer, Egas M; Zimmermann, Trelawny J; Mooshagian, Eric; Parra, Lucas C; Rice, Justin K; Datta, Abhishek; Bikson, Marom; Wassermann, Eric M

    2012-01-01

    High-Definition transcranial Direct Current Stimulation (HD-tDCS) using specialized small electrodes has been proposed as a focal, non-invasive neuromodulatory technique. Here we provide the first evidence of a change in cortical excitability after HD-tDCS of the motor cortex, using TMS motor evoked potential (MEP) as the measure of excitability. Stimulation for 20 minutes at 1 mA with an anode centered over the hand area of the motor cortex and four surrounding return electrodes (anodal 4×1 montage) produced a significant increase in MEP amplitude and variability after stimulation, compared to sham stimulation. Stimulation was well tolerated by all subjects with adverse effects limited to transient sensation under the electrodes. A high-resolution computational model confirmed predictions of increased focality using the 4×1 HD tDCS montage compared to conventional tDCS. Simulations also indicated that variability in placement of the center electrode relative to the location of the target (central sulcus) could account for increasing variability. These results provide support for the careful use of this technique where focal tDCS is desired.

  10. Some rotations like it hot: selective energy partitioning in the state resolved dynamics of collisions between CO 2 and highly vibrationally excited pyrazine

    NASA Astrophysics Data System (ADS)

    Mullin, Amy S.; Park, Jeunghee; Chou, James Z.; Flynn, George W.; Weston, Ralph E.

    1993-09-01

    The collisional quenching of highly vibrationally excited pyrazine by CO2 molecules has been studied with high resolution diode laser spectroscopy. The vibrationally hot pyrazine molecules are formed by 248 nm excimer laser pumping, followed by rapid radiationless transitions to the ground electronic state. The nascent rotational population distributions in the 0000 and 0001 vibrational levels of CO2 produced by collisions with hot pyrazine were probed at short times following excitation of pyrazine by the excimer laser pulse. In addition, the CO2 translational recoil velocity was measured for a number of rotational levels in each vibrational state. The results of these experiments reveal that very little rotational and translational excitation accompanies the energy transfer from hot pyrazine to excited vibrational levels of CO2. In contrast, rotational excitation of the CO2 ground state due to collisions with highly excited pyrazine is significant and is accompanied by a substantial enhancement in the CO2 translational energy. These results are consistent with a picture in which vibration-vibration (V → V) energy transfer processes, leading to vibrational excitation of the bath, are dominated by long range attractive forces, and vibration-translation/rotation (V → T/R) energy transfer, which leaves the bath vibrations unexcited, is dominated by short range repulsive forces.

  11. Probing the dynamics of highly excited toluene on the fs timescale.

    PubMed

    Papadopoulou, C C; Kaziannis, S; Kosmidis, C

    2015-12-21

    Investigation of the dynamics of toluene-h8 (C6H5CH3), toluene-d8 (C6D5CD3) and toluene-α,α,α-d3 (C6H5CD3) has been performed utilizing the VUV pump-IR probe technique on the fs timescale. Using the 5th harmonic (∼160 nm) of a Ti:sapphire laser as the pump beam, two superimposed electronic states, the valence S3 and the Rydberg 4p, were excited by one-photon absorption, followed by ionization and dissociation induced by the probe beam (800 nm). Analysis of the transient signal of the parent (P(+)) and fragment ions ([P-H](+) or [P-D](+)) implies the existence of two different relaxation processes: (i) from the Rydberg and (ii) from the S3 valence state. Using a rate equation model, the decay times have been determined and comparison between the different isotopologues has been made. Conclusions on the relaxation path, the relative displacements of the potential energy surfaces and the activation energies needed have been drawn from the decay times. The signals corresponding to the fragment ions present a small in amplitude, but nonetheless, unambiguous periodical modulation, which is attributed to out-of-plane bending oscillation, involving also the methyl group. The dynamics of the H- and D-loss channels has been investigated. Especially for the case of toluene-α,α,α-d3, where both channels are in operation, it was found that the ratio of the abundance of H/D-loss dissociation reactions decreases as the pump-probe delay time increases.

  12. Generation of doubly charged vortex beam by concentrated loading of glass disks along their diameter.

    PubMed

    Skab, Ihor; Vasylkiv, Yuriy; Krupych, Oleh; Savaryn, Viktoriya; Vlokh, Rostyslav

    2012-04-10

    We show that a system of glass disks compressed along their diameters enables one to induce a doubly charged vortex beam in the emergent light when the incident light is circularly polarized. Using such a disk system, one can control the efficiency of conversion of the spin angular momentum to the orbital angular momentum by a loading force. The consideration presented here can be extended for the case of crystalline materials with high optical damage thresholds in order to induce high-power vortex beams.

  13. Effects of voltage unbalance and system harmonics on the performance of doubly fed induction wind generators

    NASA Astrophysics Data System (ADS)

    Kiani, Morgan Mozhgan

    Inherent difficulties in management of electric power in the presence of an increasing demand for more energy, non-conventional loads such as digital appliances, and non-sustainable imported fossil fuels has initiated a multi-folded effort by many countries to restructure the way electric energy is generated, dispatched, and consumed. Smart power grid is the manifestation of many technologies that would eventually transforms the existing power grid into a more flexible, fault resilient, and intelligent system. Integration of distributed renewable energy sources plays a central role in successful implementation of this transformation. Among the renewable options, wind energy harvesting offers superior engineering and economical incentives with minimal environmental impacts. Doubly fed induction generators (DFIG) have turned into a serious contender for wind energy generators due to their flexibility in control of active and reactive power with minimal silicon loss. Significant presence of voltage unbalance and system harmonics in finite inertia transmission lines can potentially undermine the reliability of these wind generators. The present dissertation has investigated the impacts of system unbalances and harmonics on the performance of the DFIG. Our investigation indicates that these effects can result in an undesirable undulation in the rotor shaft which can potentially invoke mechanical resonance, thereby causing catastrophic damages to the installations and the power grid. In order to remedy the above issue, a control solution for real time monitoring of the system unbalance and optimal excitation of the three phase rotor currents in a DFIG is offered. The optimal rotor currents will create appropriate components of the magneto-motive force in the airgap that will actively compensate the undesirable magnetic field originated by the stator windings. Due to the iterative nature of the optimization procedure, field reconstruction method has been incorporated

  14. Band structure of doubly-odd nuclei around mass 130

    SciTech Connect

    Higashiyama, Koji; Yoshinaga, Naotaka

    2011-05-06

    Nuclear structure of the doublet bands in the doubly-odd nuclei with mass A{approx}130 is studied in terms of a pair-truncated shell model. The model reproduces quite well the energy levels of the doublet bands and the electromagnetic transitions. The analysis of the electromagnetic transitions reveals new band structure of the doublet bands.

  15. Doubly Lopsided Models From SUSY SU(N)

    SciTech Connect

    Barr, S. M.

    2008-11-23

    It is shown that the doubly lopsided mass matrices, which are known to give realistic patterns of quark and lepton masses and mixings, arise naturally in the context of supersymmetric grand unified models based on SU(N) with N>5. An SU(7) model is presented as an illustration.

  16. Exciting story of the high-end television projection systems and the novel compact EIDOPHOR AE-12

    NASA Astrophysics Data System (ADS)

    Schulz-Hennig, Joerg F.

    1998-04-01

    With the new light valve technologies and availability of international broad-band communication channels high-end large screen TV projection is a highly growing contribution to the multi-media world of today. The exciting story already started 58 years ago with the invention of the EIDOPHOR diffractive oil light modulator. The long way to turn electronic cinema into a reality triggered novel applications, e.g. teleconferencing and real time surgery transmissions at universities. Several technical approaches of spatial light modulation were tried, and finally several different solutions are feasible to provide video projectors, meeting the requirements of the different display applications of today and tomorrow. The technical history is reviewed and the limitations and feasibilities of new technologies are presented in respect to existing and new applications.

  17. Femtosecond plasmon and photon wave packets excited by a high-energy electron on a metal or dielectric surface

    NASA Astrophysics Data System (ADS)

    Brenny, Benjamin J. M.; Polman, Albert; García de Abajo, F. Javier

    2016-10-01

    Swift electrons generate coherent transition radiation (TR) when crossing a material surface, as well as surface plasmon polaritons (SPPs) when the material is metallic. We present analytical and numerical calculations that describe the time- and space-dependent electric fields of TR and SPPs induced by 30-300 keV electrons on a Drude metal surface. The generated SPPs form wave packets a few-hundred femtoseconds in duration, depending on the material permittivity. High-frequency components close to the plasmon resonance are strongly damped, causing the wave packets to shift to lower frequencies as they propagate further. TR is emitted to the far field as ultrashort wave packets consisting of just a few optical cycles, with an intensity and angle dependence that is determined by the material permittivity. The excitation reaches its peak amplitude within a few femtoseconds and then drops off strongly for longer times. From a correlation between material permittivity and the calculated emission behavior, we determine qualitative predictions of the TR evolution for any given material. The results presented here provide key insights into the mechanisms enabling swift electrons to serve as nanoscale optical excitation sources.

  18. Effect of Intramolecular High-Frequency Vibrational Mode Excitation on Ultrafast Photoinduced Charge Transfer and Charge Recombination Kinetics.

    PubMed

    Nazarov, Alexey E; Barykov, Vadim Yu; Ivanov, Anatoly I

    2016-03-31

    A model of photoinduced ultrafast charge separation and ensuing charge recombination into the ground state has been developed. The model includes explicit description of the formation and evolution of nonequilibrium state of both the intramolecular vibrations and the surrounding medium. An effect of the high-frequency intramolecular vibrational mode excitation by a pumping pulse on ultrafast charge separation and charge recombination kinetics has been investigated. Simulations, in accord with experiment, have shown that the effect may be both positive (the vibrational mode excitation increases the charge-transfer rate constant) and negative (opposite trend). The effect on charge separation kinetics is predicted to be bigger than that on the charge recombination rate but nevertheless the last is large enough to be observable. The amplitude of both effects falls with decreasing vibrational relaxation time constant, but the effects are expected to be observable up to the time constants as short as 200 fs. Physical interpretation of the effects has been presented. Comparisons with the experimental data have shown that the simulations, in whole, provide results close to that obtained in the experiment. The reasons of the deviations have been discussed. PMID:26953595

  19. The FERRUM project: Experimental lifetimes and transition probabilities from highly excited even 4d levels in Fe ii

    NASA Astrophysics Data System (ADS)

    Hartman, H.; Nilsson, H.; Engström, L.; Lundberg, H.

    2015-12-01

    We report lifetime measurements of the 6 levels in the 3d6(5D)4d e6G term in Fe ii at an energy of 10.4 eV, and f-values for 14 transitions from the investigated levels. The lifetimes were measured using time-resolved laser-induced fluorescence on ions in a laser-produced plasma. The high excitation energy, and the fact that the levels have the same parity as the the low-lying states directly populated in the plasma, necessitated the use of a two-photon excitation scheme. The probability for this process is greatly enhanced by the presence of the 3d6(5D)4p z6F levels at roughly half the energy difference. The f-values are obtained by combining the experimental lifetimes with branching fractions derived using relative intensities from a hollow cathode discharge lamp recorded with a Fourier transform spectrometer. The data is important for benchmarking atomic calculations of astrophysically important quantities and useful for spectroscopy of hot stars.

  20. Effect of high-optical excitation on the ultrafast electron dynamics in stacked-monolayer graphene samples

    NASA Astrophysics Data System (ADS)

    Castañeda, Juan A.; Guimarães Rosa, Henrique; Gomes, José C. V.; Thoroh de Souza, Eunezio A.; de Brito-Cruz, Carlos H.; Fragnito, Hugo L.; Padilha, Lázaro A.

    2016-05-01

    We report on transient absorption experiments performed at high optical excitation fluences and used to study the ultrafast dynamics in graphene. We employed a degenerated scheme of pump and probe at 800 nm (1.55 eV). The time resolution of our measurements was limited by the pulse duration ~ 100 fs. The samples were prepared by chemical vapor deposition (CVD) as single-layers on silica and, then staked layer-by-layer in order to make a stack of up to 5 graphene monolayers. We observed saturable absorption (SA) and fluence-dependent relaxation times. We see that the ultrafast carrier dynamics is composed by two decay mechanisms, one with response time of about 200 fs and a slower process of about 1 ps. The fast decay, due to both carrier-carrier and carrier-optical phonon scattering, becomes slower when the density of excited carrier was increased. We implemented a theoretical model and found that both the optical phonon rate emission and the optical phonon lifetime are affect by the pump fluence.

  1. Strategic emission color tuning of highly fluorescent imidazole-based excited-state intramolecular proton transfer molecules.

    PubMed

    Park, Sanghyuk; Kwon, Ji Eon; Park, Soo Young

    2012-07-01

    Highly fluorescent molecules harnessing the excited state intramolecular proton transfer (ESIPT) process are promising for a new generation of displays and light sources because they can offer very unique and novel optoelectronic properties which are different from those of conventional fluorescent dyes. To realize innovative ESIPT devices comprising full emission colors over the whole visible region, a molecular design strategy for predictable emission color tuning should be established. Here, we have developed a general strategy for a wide-range spectral tuning of imidazole-based ESIPT materials based on three different strategies--introduction of a nodal plane model, extension of effective conjugation length, and modification of heterocyclic rings. A series of nine ESIPT molecules were designed, synthesized and comprehensively investigated for their characteristic emission properties. All these molecules commonly showed no clear and transparent visible range absorption with no absorption color, but showed different colors of intense photoluminescence over broad visible regions from 450 nm (HPI) to 630 nm (HPNO) depending on their molecular structure. With the aid of density functional theory and time-dependent DFT calculations using M06, wB97XD, and B3LYP parameters with the 6-31G(d,p) basis set, these tuned emission bands of nine emitters were assigned from the stabilized excited state conformations that were derived from modified molecular structures.

  2. Chiroptical nature of two-exciton states of light-harvesting complex: Doubly resonant three-wave-mixing spectroscopy

    NASA Astrophysics Data System (ADS)

    Lee, Hochan; Cheon, Sangheon; Cho, Minhaeng

    2010-06-01

    Photosynthetic light-harvesting complex is a coupled multichromophore system. Due to electronic couplings between neighboring chlorophylls in the complex, the one- and two-exciton states are delocalized and they can be written as linear combinations of singly and doubly excited configurations, respectively. Despite that the chiroptical properties of one-exciton states in such a multichromophore system have been investigated by using linear optical activity measurement techniques; those of two-exciton states have not been studied before due to a lack of appropriate measurement methods. Here, we present a theoretical description on chiroptical χ(2) spectroscopy and show that it can be used to investigate such properties of a photosynthetic light-harvesting system, which is the Fenna-Matthews-Olson complex, consisting of seven bacteriochlorophylls in its protein subunit. To simulate the doubly resonant sum- and difference-frequency-generation spectra of the complex, one- and two-exciton transition dipoles were calculated. Carrying out quantum chemistry calculations of electronically excited states of a model bacteriochlorophyll system and taking into account the dipole-induced dipole electronic transition processes between the ground state and two-exciton states, we could calculate the two-dimensional sum-frequency-generation spectra revealing dominant second-order chiroptical transition pathways and involved one- and two-exciton states. It is believed that the present computational scheme and the theoretically proposed doubly resonant two-dimensional three-wave-mixing spectroscopy would be of use to shed light on the chiroptical natures of two-exciton states of arbitrary coupled multichromophore systems.

  3. Fragmentation Patterns and Mechanisms of Singly and Doubly Protonated Peptoids Studied by Collision Induced Dissociation

    NASA Astrophysics Data System (ADS)

    Ren, Jianhua; Tian, Yuan; Hossain, Ekram; Connolly, Michael D.

    2016-04-01

    Peptoids are peptide-mimicking oligomers consisting of N-alkylated glycine units. The fragmentation patterns for six singly and doubly protonated model peptoids were studied via collision-induced dissociation tandem mass spectrometry. The experiments were carried out on a triple quadrupole mass spectrometer with an electrospray ionization source. Both singly and doubly protonated peptoids were found to fragment mainly at the backbone amide bonds to produce peptoid B-type N-terminal fragment ions and Y-type C-terminal fragment ions. However, the relative abundances of B- versus Y-ions were significantly different. The singly protonated peptoids fragmented by producing highly abundant Y-ions and lesser abundant B-ions. The Y-ion formation mechanism was studied through calculating the energetics of truncated peptoid fragment ions using density functional theory and by controlled experiments. The results indicated that Y-ions were likely formed by transferring a proton from the C-H bond of the N-terminal fragments to the secondary amine of the C-terminal fragments. This proton transfer is energetically favored, and is in accord with the observation of abundant Y-ions. The calculations also indicated that doubly protonated peptoids would fragment at an amide bond close to the N-terminus to yield a high abundance of low-mass B-ions and high-mass Y-ions. The results of this study provide further understanding of the mechanisms of peptoid fragmentation and, therefore, are a valuable guide for de novo sequencing of peptoid libraries synthesized via combinatorial chemistry.

  4. The Torsional Spectrum of Doubly Deuterated Methanol CHD_2OH

    NASA Astrophysics Data System (ADS)

    Ndao, M.; Coudert, L. H.; Kwabia Tchana, F.; Barros, J.; Margulès, L.; Manceron, Laurent; Roy, P.

    2014-06-01

    Although the torsional spectrum of several isotopic species of methanol with a symmetrical CH_3 or CD_3 was analyzed some time ago, it is recently, and only for the monodeuterated species CH_2DOH, that such an analysis was extended to the case of an asymmetrical methyl group. In this talk, based on a Fourier transform high-resolution spectrum recorded in the 20 to 670 wn region, the first analysis of the torsional spectrum of doubly deuterated methanol CHD_2OH will be presented. The Q branch of many torsional subbands could be observed and their assignment was initiated using a theoretical torsion-rotation spectrum computed with an approach accounting for the torsion-rotation Coriolis coupling and for the dependence of the generalized inertia tensor on the angle of internal rotation. 46 torsional subbands were thus assigned. For 28 of them, their rotational structure could be assigned and fitted using an effective Hamiltonian expressed as a J(J+1) expansion; and for 2 of them microwave transitions within the lower torsional level could also be included in the analysis. In several cases these analysis revealed that the torsional levels are strongly perturbed. In the talk, the torsional parameters retrieved in the analysis of the torsional subband centers will be discussed. The results of the analysis of the rotational structure of the torsional subbands will be presented and we will also try to understand the nature of the perturbations. At last, preliminary results about the analysis of the microwave spectrum will be presented. El Hilali, Coudert, Konov, and Klee, J. Chem. Phys. 135 (2011) 194309 Lauvergnat, Coudert, Klee, and Smirnov, J. Mol. Spectrosc. 256 (2009) 204 Quade, Liu, Mukhopadhyay, and Su, J. Mol. Spectrosc. 192 (1998) 378 Pearson, Yu, and Drouin, J. Mol. Spectrosc. 280 (2012) 119

  5. Additions to the spectrum and energy levels and critical compilation of doubly ionized boron, B III

    NASA Astrophysics Data System (ADS)

    Kramida, A. E.; Ryabtsev, A. N.; Ekberg, J. O.; Kink, I.; Mannervik, S.; Martinson, I.

    2008-08-01

    We have undertaken the study of the Li-like spectrum of doubly ionized boron, B III. The spectroscopic data have been obtained with beam-foil spectroscopy and high-resolution spark spectroscopy. The experimental work was combined with theoretical calculations using ab initio and semi-empirical techniques. About 50 new transitions have been observed, and most of the previously known lines have been measured with improved accuracy. We have also critically evaluated all previous and recent data for this spectrum. Complete data on wavelengths and energy levels based on this analysis are tabulated.

  6. Excitation of High-Frequency Internal Kink Mode by Deeply-Trapped Energetic Ions

    NASA Astrophysics Data System (ADS)

    Li, Wen; Wang, Shaojie

    2010-08-01

    Deeply trapped energetic ions can destabilize the internal kink mode with both high and low frequencies with a potato-orbit limit in the EAST-like tokamaks. The threshold beta value of the deeply trapped energetic ions, the real frequency, and the growth rate of the internal kink mode are predicted in this paper.

  7. High resolution detection and excitation of resonant magnetic perturbations in a wall-stabilized tokamak

    SciTech Connect

    Maurer, David A.; Shiraki, Daisuke; Levesque, Jeffrey P.; Bialek, James; Angelini, Sarah; Byrne, Patrick; DeBono, Bryan; Hughes, Paul; Mauel, Michael E.; Navratil, Gerald A.; Peng Qian; Rhodes, Dov; Rath, Nickolaus; Stoafer, Christopher

    2012-05-15

    We report high-resolution detection of the 3D plasma magnetic response of wall-stabilized tokamak discharges in the High Beta Tokamak-Extended Pulse [T. H. Ivers et al., Phys. Plasmas 3, 1926 (1996)] device. A new adjustable conducting wall has been installed on HBT-EP made up of 20 independent, movable, wall segments instrumented with three distinct sets of 40 modular coils that can be independently driven to generate a wide variety of magnetic perturbations. High-resolution detection of the plasma response is made with 216 poloidal and radial magnetic sensors that have been located and calibrated with high-accuracy. Static and dynamic plasma responses to resonant and non-resonant magnetic perturbations are observed through measurement of the step-response following a rapid change in the toroidal phase of the applied perturbations. Biorthogonal decomposition of the full set of magnetic sensors clearly defines the structures of naturally occurring external kinks as being composed of independent m/n = 3/1 and 6/2 modes. Resonant magnetic perturbations were applied to discharges with pre-existing, saturated m/n = 3/1 external kink mode activity. This m/n = 3/1 kink mode was observed to lock to the applied perturbation field. During this kink mode locked period, the plasma resonant response is characterized by a linear, a saturated, and a disruptive plasma regime dependent on the magnitude of the applied field and value of the edge safety factor and plasma rotation.

  8. Highly vibrationally excited CO generated in a low-temperature chemical reaction between carbon vapor and molecular oxygen

    NASA Astrophysics Data System (ADS)

    Jans, E.; Frederickson, K.; Yurkovich, M.; Musci, B.; Rich, J. W.; Adamovich, I. V.

    2016-08-01

    A chemical flow reactor is used to study the vibrational population distribution of CO produced by a reaction between carbon vapor generated in an arc discharge and molecular oxygen. The results demonstrate formation of highly vibrationally excited CO, up to vibrational level v = 14, at low temperatures, T = 400-450 K, with population inversion at v = 4-7, in a collision-dominated environment, 15-20 Torr. The average vibrational energy per CO molecule formed by the reaction is 0.6-1.2 eV/molecule, which corresponds to 10-20% of reaction enthalpy. The results show feasibility of development of a new CO chemical laser using carbon vapor and oxygen as reactants.

  9. Measurements of High-energy Excited States and γ-rays of Fission Products with a 4π Clover Detector

    SciTech Connect

    Shima, Y.; Kojima, Y.; Hayashi, H.; Taniguchi, A.; Shibata, M.

    2014-06-15

    Gamma-rays in the β-decay of {sup 147}La and {sup 145}Ba were measured using a 4π clover detector to identify high-energy excited levels and γ-rays. In order to determine γ-ray intensities, an efficiency calibration was carried out using single and multiple γ-ray emitters. Applying appropriate coincidence summing corrections, the peak efficiency was experimentally determined from 50 to 3200 keV with 3% accuracy. Through analyses of sum peaks and cascade relations of γ-rays, we newly identified 170 levels between 924 and 3568 keV, and more than 930 γ-rays in the decay of {sup 147}La, and 70 levels between 973 and 3703 keV, and 250 γ-rays in the decay of {sup 145}Ba.

  10. The Study of Dynamic Potentials of Highly Excited Vibrational States of DCP: From Case Analysis to Comparative Study with HCP.

    PubMed

    Wang, Aixing; Fang, Chao; Liu, Yibao

    2016-08-22

    The dynamic potentials of highly excited vibrational states of deuterated phosphaethyne (DCP) in the D-C and C-P stretching coordinates with anharmonicity and Fermi coupling are studied in this article and the results show that the D-C-P bending vibration mode has weak effects on D-C and C-P stretching modes under different Polyad numbers (P number). Furthermore, the dynamic potentials and the corresponding phase space trajectories of DCP are given, as an example, in the case of P = 30. In the end, a comparative study between deuterated phosphaethyne (DCP) and phosphaethyne (HCP) with dynamic potential is done, and it is elucidated that the uncoupled mode makes the original horizontal reversed symmetry breaking between the dynamic potential of HCP ( q 3 ) and DCP ( q 1 ), but has little effect on the vertical reversed symmetry, between the dynamic potential of HCP ( q 2 ) and DCP ( q 3 ).

  11. The Study of Dynamic Potentials of Highly Excited Vibrational States of DCP: From Case Analysis to Comparative Study with HCP

    PubMed Central

    Wang, Aixing; Fang, Chao; Liu, Yibao

    2016-01-01

    The dynamic potentials of highly excited vibrational states of deuterated phosphaethyne (DCP) in the D–C and C–P stretching coordinates with anharmonicity and Fermi coupling are studied in this article and the results show that the D-C-P bending vibration mode has weak effects on D–C and C–P stretching modes under different Polyad numbers (P number). Furthermore, the dynamic potentials and the corresponding phase space trajectories of DCP are given, as an example, in the case of P = 30. In the end, a comparative study between deuterated phosphaethyne (DCP) and phosphaethyne (HCP) with dynamic potential is done, and it is elucidated that the uncoupled mode makes the original horizontal reversed symmetry breaking between the dynamic potential of HCP (q3) and DCP (q1), but has little effect on the vertical reversed symmetry, between the dynamic potential of HCP (q2) and DCP (q3). PMID:27556452

  12. The Study of Dynamic Potentials of Highly Excited Vibrational States of DCP: From Case Analysis to Comparative Study with HCP.

    PubMed

    Wang, Aixing; Fang, Chao; Liu, Yibao

    2016-01-01

    The dynamic potentials of highly excited vibrational states of deuterated phosphaethyne (DCP) in the D-C and C-P stretching coordinates with anharmonicity and Fermi coupling are studied in this article and the results show that the D-C-P bending vibration mode has weak effects on D-C and C-P stretching modes under different Polyad numbers (P number). Furthermore, the dynamic potentials and the corresponding phase space trajectories of DCP are given, as an example, in the case of P = 30. In the end, a comparative study between deuterated phosphaethyne (DCP) and phosphaethyne (HCP) with dynamic potential is done, and it is elucidated that the uncoupled mode makes the original horizontal reversed symmetry breaking between the dynamic potential of HCP ( q 3 ) and DCP ( q 1 ), but has little effect on the vertical reversed symmetry, between the dynamic potential of HCP ( q 2 ) and DCP ( q 3 ). PMID:27556452

  13. Formation and annihilation of intrinsic defects induced by electronic excitation in high-purity crystalline SiO{sub 2}

    SciTech Connect

    Kajihara, Koichi; Skuja, Linards; Hosono, Hideo

    2013-04-14

    Formation and thermal annihilation of intrinsic defects in {alpha}-quartz were examined using high-purity samples, while minimizing the contributions of reactions involving metallic impurities. Electronic excitation with {sup 60}Co {gamma}-rays was employed to avoid radiation-induced amorphization. The results clearly show that formation of oxygen vacancies (Si-Si bonds) as a result of decomposition of regular Si-O-Si bonds (Frenkel process) is the dominant intrinsic defect process. Compared with amorphous SiO{sub 2}, in {alpha}-quartz, the formation yield of Si-Si bonds is an order of magnitude smaller, the 7.6 eV optical absorption band is less broadened, and their thermal annihilation is complete at a lower temperature, around the {alpha}-{beta} quartz transition. In contrast, radiation-induced interstitial oxygen atoms practically do not form interstitial oxygen molecules.

  14. Wide field intravital imaging by two-photon-excitation digital-scanned light-sheet microscopy (2p-DSLM) with a high-pulse energy laser

    PubMed Central

    Maruyama, Atsushi; Oshima, Yusuke; Kajiura-Kobayashi, Hiroko; Nonaka, Shigenori; Imamura, Takeshi; Naruse, Kiyoshi

    2014-01-01

    Digital-scanned light-sheet microscopy (DSLM) illuminates a sample in a plane and captures single-photon–excitation fluorescence images with a camera from a direction perpendicular to the light sheet. This method is potentially useful for observing biological specimens, because image acquisition is relatively fast, resulting in reduction of phototoxicity. However, DSLM cannot be effectively applied to high-scattering materials due to the image blur resulting from thickening of the light sheet by scattered photons. However, two-photon–excitation DSLM (2p-DSLM) enables collection of high-contrast image with near infrared (NIR) excitation. In conventional 2p-DSLM, the minimal excitation volume for two-photon excitation restricts the field of view. In this study, we achieved wide-field 2p-DSLM by using a high–pulse energy fiber laser, and then used this technique to perform intravital imaging of a small model fish species, medaka (Oryzias latipes). Wide fields of view (>700 μm) were achieved by using a low–numerical aperture (NA) objective lens and high–peak energy NIR excitation at 1040 nm. We also performed high-speed imaging at near-video rate and successfully captured the heartbeat movements of a living medaka fish at 20 frames/sec. PMID:25360352

  15. HST Images of the High-Excitation Herbig-Haro Object HH 32

    NASA Astrophysics Data System (ADS)

    Curiel, S.; Raga, A.; Raymond, J.; Noriega-Crespo, A.; Canto, J.

    1997-12-01

    We present high angular resolution emission-line and continuum images of the remarkable Herbig-Haro jet HH 32 obtained with the Wide Field and Planetary Camera 2 (WFPC2) aboard the Hubble Space Telescope. We have obtained narrow band [S ii] λλ6716,673l, [N ii] 6583 and Hα images, as well as an R continuum image, of this HH jet. The 0."l spatial resolution (corresponding to 30 AU at the distance of HH 32) and the high signal-to-noise ratio of these WFPC2 images allow us to study this highly collimated outflow in unprecedented detail. The images show differences between the stratification of the different emission lines. The knots are clearly resolved into complex structures that resemble working surfaces. The western side of the jet starts in a funnel-shaped structure that points toward the bright condensations HH 32D, 32B, and 32A, while on the other side of the jet the dominant structure is an arc-like feature that points almost directly away from the young star AS 353A. The HH 32A condensation exhibits a region strong in [S ii] that we identify as the Mach Disk at the tip of the jet. Finally, the HST images are used in combination with previous, high resolution ground based observations (obtained with the Canada-France-Hawaii telescope) to obtain proper motion determinations. We find that the kinematical properties deduced from these proper motions are consistent with those of a jet moving at about 300 km/s, penetrating into the maternal cloud at an angle of 70° between the outflow axis and the plane of the sky. This is also consistent with the properties deduced from previously obtained high resolution spectra of HH 32. We find that the kinematical properties deduced from these proper motions are completely consistent with previous proper motion measurements, as well as with the properties deduced from previously obtained, high resolution spectra of HH 32.

  16. Accurate calculation and assignment of highly excited vibrational levels of floppy triatomic molecules in a basis of adiabatic vibrational eigenstates

    NASA Astrophysics Data System (ADS)

    Bačić, Z.

    1991-09-01

    We show that the triatomic adiabatic vibrational eigenstates (AVES) provide a convenient basis for accurate discrete variable representation (DVR) calculation and automatic assignment of highly excited, large amplitude motion vibrational states of floppy triatomic molecules. The DVR-AVES states are eigenvectors of the diagonal (in the stretch states) blocks of the adiabatically rearranged triatomic DVR-ray eigenvector (DVR-REV) Hamiltonian [J. C. Light and Z. Bačić, J. Chem. Phys. 87, 4008 (1987)]. The transformation of the full triatomic vibrational Hamiltonian from the DVR-REV basis to the new DVR-AVES basis is simple, and does not involve calculation of any new matrix elements. No dynamical approximation is made in the energy level calculation by the DVR-AVES approach; its accuracy and efficiency are identical to those of the DVR-REV method. The DVR-AVES states, as the adiabatic approximation to the vibrational states of a triatomic molecule, are labeled by three vibrational quantum numbers. Consequently, accurate large amplitude motion vibrational levels obtained by diagonalizing the full vibrational Hamiltonian transformed to the DVR-AVES basis, can be assigned automatically by the code, with the three quantum numbers of the dominant DVR-AVES state associated with the largest (by modulus) eigenvector element in the DVR-AVES basis. The DVR-AVES approach is used to calculate accurate highly excited localized and delocalized vibrational levels of HCN/HNC and LiCN/LiNC. A significant fraction of localized states of both systems, below and above the isomerization barrier, is assigned automatically, without inspection of wave function plots or separate approximate calculations.

  17. High-pressure studies of photoluminescence and thermoluminescence of ZnS:Cu:Cl phosphors using laser selection excitation

    SciTech Connect

    Lang, J.M.; Dreger, Z.A.; Drickamer, H.G.

    1992-01-09

    The authors have measured the effect of pressure on the luminescence and thermoluminescence characteristics of three ZnS phosphors doped with Cu and Cl. The total dopant concentration varied in the ratio 1/1.5/2.5, but the Cl/Cu ratio was constant at {approximately}8/1. The excitation was via the 325-nm (3.82-eV) line of a He-Cd laser. The absorption edge of ZnS is at 3.67 eV at 1 atm and increases by 6.35 meV/kbar, so that at high pressure the excitation is to {open_quotes}deep levels{close_quotes} provided by the Cl. The emission consists of two peaks at 20,000 and 22,000 cm{sup {minus}1} assigned to emission from a Cl{sup {minus}} center to a Zn vacancy and a Cu{sup +} center, respectively. Both emission peaks increased in energy with pressure. The shifts could be explained in terms of the degree of pinning of donor and acceptor levels to the conduction and valence bands. The thermoluminescence data indicated an initial trap depth of 0.3 eV for all three samples. This trap depth increased with pressure at low pressures but leveled at 0.39, 0.46, and 0.54 eV for the high-, intermediate-, and low-concentration samples, respectively. The thermoluminescence intensity decreased by 2 orders of magnitude in 40 kbar. The behavior of the thermoluminescence could be explained largely by differences in the nature and behavior of the {open_quotes}deep levels{close_quotes} initially in the conduction band. 28 refs., 10 figs., 2 tabs.

  18. Production of a Beam of Highly Vibrationally Excited CO Using Perturbations

    NASA Astrophysics Data System (ADS)

    Bartels, N.; Schäfer, T.; Hühnert, J.; Wodtke, A. M.; Field, R. W.

    2012-06-01

    For many experimentalists (especially those, who are not spectroscopists), molecular pertubations are a curse, as they make assignments and analysis of spectral data more difficult. Nevertheless, they can also be a boon! In this talk we will show how a molecular beam of CO in high vibrational states (v=17,18) can be prepared by an optical pumping scheme that we call PUMP-PUMP-PERTURB and DUMP (P^3D). P^3D exploits the loaning, via spin-orbit perturbations, of the large oscillator strength of the 4th positive system, A ^1 π ← X ^1 Σ ^+, to the triplet manifold. This allows some nominally spin-forbidden transitions to be exploited in multistep optical pumping schemes. The ability to {state-selectively} prepare CO in high vibrational states opens up new opportunities for molecular beam scattering experiments.

  19. Ultrasensitive and High-Throughput Fluorescence Analysis of Droplet Contents with Orthogonal Line Confocal Excitation

    PubMed Central

    Jeffries, Gavin D.M.; Lorenz, Robert M.; Chiu, Daniel T.

    2010-01-01

    This paper describes a simple modification to traditional confocal fluorescence detection that greatly improves signal-to-noise (S/N) for the high-speed analysis of droplet streams. Rather than using the conventional epi geometry, illumination of the droplet was in the form of a line that is orthogonal to both the direction of flow and the light-collection objective. In contrast to the epi geometry where we observed high levels of scattering background from the droplets, we detected more than 10-fold less background (depending on the laser power used) when orthogonal-line-confocal illumination was used. We characterized this improvement using a standard microfluidic platform over a range of analyte concentrations, and observed an improvement in limits of detection of greater than 10. Using this method, we were able to analyze pico-molar concentrations of analytes contained within picoliter-volume droplets at a rate of greater than 350 droplets per second. PMID:21062029

  20. Highly efficient and two-photon excited stimulated Rayleigh-Bragg scattering in organic solutions

    SciTech Connect

    He, Guang S. Prasad, Paras N.; Kannan, Ramamurthi; Tan, Loon-Seng

    2015-07-21

    The properties of backward stimulated Rayleigh-Bragg scattering (SRBS) in three highly two-photon active AF-chromophores solutions in tetrahydrofuran (THF) have been investigated using 816-nm and 8-ns pump laser beam. The nonlinear reflectivity R, spectral structure, temporal behavior, and phase-conjugation capability of the backward SRBS output have been measured, respectively. Under the same experimental condition, the pump threshold for SRBS in three solution samples can be significantly (∼one order of magnitude) lower than that for stimulated Brillouin scattering (SBS) in the pure solvent (THF). With the optimized concentration value and at a moderate pump energy (∼1.5 mJ) level, the measured nonlinear reflectivity was R ≥ 35% for the 2 cm-long solution sample, while for the SBS from a pure solvent sample of the same length was R ≈ 4.7%. The peculiar features of very low pump threshold, no spectral shift, tolerant pump spectral linewidth requirement (≤1 cm{sup −1}), and phase-conjugation capability are favorable for those nonlinear photonics applications, such as highly efficiency phase-conjugation reflectors for high-brightness laser oscillator/amplifier systems, special imaging through turbid medium, self-adaptive remote optical sensing, as well as for optical rangefinder and lidar systems.

  1. Near-threshold electron-impact doubly differential cross sections for the ionization of argon and krypton

    SciTech Connect

    Yates, Brent R.; Khakoo, Murtadha A.

    2011-04-15

    We present normalized doubly differential cross sections (DDCS's) for the near-threshold, electron-impact single ionization of argon and krypton, similar to those taken earlier for Ne and Xe [Yates et al., J. Phys. B 42, 095206 (2009)]. The Ar measurements were taken at incident energies of 17, 18, 20, and 30 eV while the Kr measurements were taken at 15, 16, 17.5, and 20 eV. The DDCS scattering angles range from 15 deg. to 120 deg. The differential data are initially normalized to available experimental cross sections for excitation of the ground np{sup 6} to the np{sup 5}(n+1)s excited states of the noble gas and, after integration, to well-established experimental total ionization cross sections of Rapp and Englander-Golden [J. Chem. Phys. 43, 1464 (1965)].

  2. High-harmonic generation by nonlinear resonant excitation of surface plasmon modes in metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Hurst, Jérôme; Haas, Fernando; Manfredi, Giovanni; Hervieux, Paul-Antoine

    2014-04-01

    The nonlinear electron dynamics in metallic nanoparticles is studied using a hydrodynamic model that incorporates most quantum many-body features, including spill-out and nonlocal effects as well as electron exchange and correlations. We show that, by irradiating the nanoparticle with a chirped laser pulse of modest intensity (autoresonance), it is possible to drive the electron dynamics far into the nonlinear regime, leading to enhanced energy absorption and complete ionization of the nanoparticle on a time scale of the order of 100 fs. The accompanying radiated power spectrum is rich in high-order harmonics.

  3. Highly Efficient and Excitation Tunable Two-Photon Luminescence Platform For Targeted Multi-Color MDRB Imaging Using Graphene Oxide

    PubMed Central

    Pramanik, Avijit; Fan, Zhen; Chavva, Suhash Reddy; Sinha, Sudarson Sekhar; Ray, Paresh Chandra

    2014-01-01

    Multiple drug-resistance bacteria (MDRB) infection is one of the top three threats to human health according to the World Health Organization (WHO). Due to the large penetration depth and reduced photodamage, two-photon imaging is an highly promising technique for clinical MDRB diagnostics. Since most commercially available water-soluble organic dyes have low two-photon absorption cross-section and rapid photobleaching tendency, their applications in two-photon imaging is highly limited. Driven by the need, in this article we report extremely high two-photon absorption from aptamer conjugated graphene oxide (σ2PA = 50800 GM) which can be used for highly efficient two-photon fluorescent probe for MDRB imaging. Reported experimental data show that two-photon photoluminescence imaging color, as well as luminescence peak position can be tuned from deep blue to red, just by varying the excitation wavelength without changing its chemical composition and size. We have demonstrated that graphene oxide (GO) based two-photon fluorescence probe is capable of imaging of multiple antibiotics resistance MRSA in the first and second biological transparency windows using 760–1120 nm wavelength range. PMID:25125143

  4. Highly Efficient and Excitation Tunable Two-Photon Luminescence Platform For Targeted Multi-Color MDRB Imaging Using Graphene Oxide

    NASA Astrophysics Data System (ADS)

    Pramanik, Avijit; Fan, Zhen; Chavva, Suhash Reddy; Sinha, Sudarson Sekhar; Ray, Paresh Chandra

    2014-08-01

    Multiple drug-resistance bacteria (MDRB) infection is one of the top three threats to human health according to the World Health Organization (WHO). Due to the large penetration depth and reduced photodamage, two-photon imaging is an highly promising technique for clinical MDRB diagnostics. Since most commercially available water-soluble organic dyes have low two-photon absorption cross-section and rapid photobleaching tendency, their applications in two-photon imaging is highly limited. Driven by the need, in this article we report extremely high two-photon absorption from aptamer conjugated graphene oxide (σ2PA = 50800 GM) which can be used for highly efficient two-photon fluorescent probe for MDRB imaging. Reported experimental data show that two-photon photoluminescence imaging color, as well as luminescence peak position can be tuned from deep blue to red, just by varying the excitation wavelength without changing its chemical composition and size. We have demonstrated that graphene oxide (GO) based two-photon fluorescence probe is capable of imaging of multiple antibiotics resistance MRSA in the first and second biological transparency windows using 760-1120 nm wavelength range.

  5. Single particle tracking through highly scattering media with multiplexed two-photon excitation

    NASA Astrophysics Data System (ADS)

    Perillo, Evan; Liu, Yen-Liang; Liu, Cong; Yeh, Hsin-Chih; Dunn, Andrew K.

    2015-03-01

    3D single-particle tracking (SPT) has been a pivotal tool to furthering our understanding of dynamic cellular processes in complex biological systems, with a molecular localization accuracy (10-100 nm) often better than the diffraction limit of light. However, current SPT techniques utilize either CCDs or a confocal detection scheme which not only suffer from poor temporal resolution but also limit tracking to a depth less than one scattering mean free path in the sample (typically <15μm). In this report we highlight our novel design for a spatiotemporally multiplexed two-photon microscope which is able to reach sub-diffraction-limit tracking accuracy and sub-millisecond temporal resolution, but with a dramatically extended SPT range of up to 200 μm through dense cell samples. We have validated our microscope by tracking (1) fluorescent nanoparticles in a prescribed motion inside gelatin gel (with 1% intralipid) and (2) labeled single EGFR complexes inside skin cancer spheroids (at least 8 layers of cells thick) for ~10 minutes. Furthermore we discuss future capabilities of our multiplexed two-photon microscope design, specifically to the extension of (1) simultaneous multicolor tracking (i.e. spatiotemporal co-localization analysis) and (2) FRET studies (i.e. lifetime analysis). The high resolution, high depth penetration, and multicolor features of this microscope make it well poised to study a variety of molecular scale dynamics in the cell, especially related to cellular trafficking studies with in vitro tumor models and in vivo.

  6. High-excitation lines of deuterated formaldehyde (HDCO) in the Orion Molecular Cloud

    NASA Astrophysics Data System (ADS)

    Loren, R. B.; Wootten, A.

    1985-12-01

    Five HDCO lines (up to 35 cm-1) have been detected in the narrow OMC-1 kinematic component. The best estimate of the [HDCO]/[H2CO] abundance ratio in OMC-1 is 0.01-0.03, at least an order of magnitude greater than the observed [DCO+]/[HCO+] abundance ratio. The [DCO+]/[HCO+] ratio greatly exceeds the [HDCO]/[H2CO] ratio in cold clouds where the enhancement of both HDCO and DCO+ abundances originates from H2D+. H2D+ is abundant only at temperatures lower than found in OMC- 1. The combination of a low [DCO+]/[HCO+] and high [HDCO]/[H2CO] abundance ratio in OMC-1 requires a different HDCO formation route at high temperature. This alternate HDCO formation path can occur because the exothermicity of the ion exchange reaction of HD and CH3+ is greater than for the HD + H3+ reaction. The CH2D+ thus formed survives to higher temperatures than H2D+. Subsequent reactions with H2 lead to CH4D+ which by electronic recombination forms CH2D. The HDCO (H2CO) forms in the neutral-neutral reaction of CH2D (CH3) and O. These reactions are not competitive in forming a variety of deuterated molecules at low temperatures since electronic recombination rapidly removes CH2D+ and CH4D+ ions while the abundant H2D+ ion is slow to recombine, as reported by Smith and Adam in 1984.

  7. Accurate and highly efficient calculation of the highly excited pure OH stretching resonances of O(1D)HCl, using a combination of methods.

    PubMed

    Bian, Wensheng; Poirier, Bill

    2004-09-01

    Accurate calculation of the energies and widths of the resonances of HOCl--an important intermediate in the O(1D)HCl reactive system--poses a challenging benchmark for computational methods. The need for very large direct product basis sets, combined with an extremely high density of states, results in difficult convergence for iterative methods. A recent calculation of the highly excited OH stretch mode resonances using the filter diagonalization method, for example, required 462,000 basis functions, and 180,000 iterations. In contrast, using a combination of new methods, we are able to compute the same resonance states to higher accuracy with a basis less than half the size, using only a few hundred iterations-although the CPU cost per iteration is substantially greater. Similar performance enhancements are observed for calculations of the high-lying bound states, as reported in a previous paper [J. Theo. Comput. Chem. 2, 583 (2003)].

  8. Cyclodextrin complexed [60]fullerene derivatives with high levels of photodynamic activity by long wavelength excitation.

    PubMed

    Ikeda, Atsushi; Iizuka, Tatsuya; Maekubo, Naotake; Aono, Ryota; Kikuchi, Jun-Ichi; Akiyama, Motofusa; Konishi, Toshifumi; Ogawa, Takuya; Ishida-Kitagawa, Norihiro; Tatebe, Hisashi; Shiozaki, Kazuhiro

    2013-08-01

    We have evaluated the photodynamic activities of C60 derivative·γ-cyclodextrin (γ-CDx) complexes and demonstrated that they were significantly higher than those of the pristine C60 and C70·γ-CDx complexes under photoirradiation at long wavelengths (610-720 nm), which represent the optimal wavelengths for photodynamic therapy (PDT). In particular, the cationic C60 derivative·γ-CDx complex had the highest photodynamic ability because the complex possessed the ability to generate high levels of (1)O2 and provided a higher level of intracellular uptake. The photodynamic activity of this complex was greater than that of photofrin, which is the most widely used of the known clinical photosensitizers. These findings therefore provide a significant level of information toward the optimization of molecular design strategies for the synthesis of fullerene derivatives for PDT. PMID:24900742

  9. Satellite bands of the RbCs molecule in the range of highly excited states

    NASA Astrophysics Data System (ADS)

    Rakić, Mario; Beuc, Robert; Bouloufa-Maafa, Nadia; Dulieu, Olivier; Vexiau, Romain; Pichler, Goran; Skenderović, Hrvoje

    2016-05-01

    We report on the observation of three RbCs satellite bands in the blue and green ranges of the visible spectrum. Absorption measurements are performed using all-sapphire cell filled with a mixture of Rb and Cs. We compare high resolution absorption spectrum of Rb-Cs vapor mixture with pure Rb and Cs vapor spectra from the literature. After detailed analysis, the new satellite bands of RbCs molecule at 418.3 nm, 468.3, and 527.5 nm are identified. The origin of these bands is discussed by direct comparison with difference potentials derived from quantum chemistry calculations of RbCs potential energy curves. These bands originate from the lower Rydberg states of the RbCs molecule. This study thus provides further insight into photoassociation of lower Rydberg molecular states, approximately between Cs(7s) + Rb(5s) and Cs(6s) + Rb(6p) asymptotes, in ultracold gases.

  10. Near Infrared Emission of Highly Electronically Excited CO: A Sensitive Probe to Study the Interstellar Medium??

    NASA Technical Reports Server (NTRS)

    Gudipati, Murthy S.

    2002-01-01

    Among the various spectroscopic features of the second most abundant molecule in the space, CO, "the triplet - triplet transitions involving the lowest triplet state a(sup 3)II and the higher-lying a(sup 1)3 SIGMA (sup +), d(sup 3) (DELTA), e (sup 3) SIGMA (sup -) states spanning near-UV to mid-IR spectral range" have so far not been explored in astrophysical observations. The energies of these transitions are highly sensitive to the surroundings in which CO exists, i.e. gas-phase, polar or non-polar condensed phase. It is proposed here that these triplet-triplet emission/absorption bands can be used as a sensitive probe to investigate the local environments of CO, whether in the planetary atmosphere, stellar atmosphere or interstellar medium.

  11. Production of autoionizing Rydberg states by transfer excitation in high energy ion atom collisions

    SciTech Connect

    Stolterfoht, N.; Miller, P.D.; Krause, H.F.; Yamazaki, Y.; Dittner, P.F.; Pepmiller, P.L.; Sellin, I.A.; Datz, S.

    1986-01-01

    The method of zero-degree Auger spectroscopy was used to study the production of autoionizing Rydberg states in collisions of carbon and oxygen projectiles incident at several MeV on He gas and carbon foils. The autoionization electrons were measured with high resolution so that the quantum defect corresponding to the angular momenta of the Rydberg electrons could be observed. The main purpose of the present experiment is to gain information about the n and l distribution of the Rydberg electron captured in the collision. The well-known n/sup -3/ law is confirmed. For the He gas target it is found that the angular momenta p and d are predominantly produced. For the foil target the higher angular momenta are clearly enhanced. 15 refs., 6 figs.

  12. Propagation and Breaking at High Altitudes of Gravity Waves Excited by Tropospheric Forcing

    NASA Technical Reports Server (NTRS)

    Prusa, Joseph M.; Smolarkiewicz, Piotr K.; Garcia, Rolando R.

    1996-01-01

    An anelastic approximation is used with a time-variable coordinate transformation to formulate a two-dimensional numerical model that describes the evolution of gravity waves. The model is solved using a semi-Lagrangian method with monotone (nonoscillatory) interpolation of all advected fields. The time-variable transformation is used to generate disturbances at the lower boundary that approximate the effect of a traveling line of thunderstorms (a squall line) or of flow over a broad topographic obstacle. The vertical propagation and breaking of the gravity wave field (under conditions typical of summer solstice) is illustrated for each of these cases. It is shown that the wave field at high altitudes is dominated by a single horizontal wavelength; which is not always related simply to the horizontal dimension of the source. The morphology of wave breaking depends on the horizontal wavelength; for sufficiently short waves, breaking involves roughly one half of the wavelength. In common with other studies, it is found that the breaking waves undergo "self-acceleration," such that the zonal-mean intrinsic frequency remains approximately constant in spite of large changes in the background wind. It is also shown that many of the features obtained in the calculations can be understood in terms of linear wave theory. In particular, linear theory provides insights into the wavelength of the waves that break at high altitudes, the onset and evolution of breaking. the horizontal extent of the breaking region and its position relative to the forcing, and the minimum and maximum altitudes where breaking occurs. Wave breaking ceases at the altitude where the background dissipation rate (which in our model is a proxy for molecular diffusion) becomes greater than the rate of dissipation due to wave breaking, This altitude, in effect, the model turbopause, is shown to depend on a relatively small number of parameters that characterize the waves and the background state.

  13. Mass Spectrometric Observation of Doubly Charged Alkaline-Earth Argon Ions.

    PubMed

    Hattendorf, Bodo; Gusmini, Bianca; Dorta, Ladina; Houk, Robert S; Günther, Detlef

    2016-09-01

    Doubly charged diatomic ions MAr(2+) where M=Mg, Ca, Sr or Ba have been observed by mass spectrometry with an inductively coupled plasma ion source. Abundance ratios are quite high, 0.1 % for MgAr(2+) , 0.4 % for CaAr(2+) , 0.2 % for SrAr(2+) and 0.1 % for BaAr(2+) relative to the corresponding doubly charged atomic ions M(2+) . It is assumed that these molecular ions are formed through reactions of the doubly charged metal ions with neutral argon atoms within the ion source. Bond dissociation energies (D0 ) were calculated and agree well with previously published values. The abundance ratios MAr(+) /M(+) and MAr(2+) /M(2+) generally follow the predicted bond dissociation energies with the exception of MgAr(2+) . Mg(2+) should form the strongest bond with Ar [D0 (MgAr(2+) )=124 to 130 kJ mol(-1) ] but its relative abundance is similar to that of the weakest bound BaAr(2+) (D0 =34 to 42 kJ mol(-1) ). The relative abundances of the various MAr(2+) ions are higher than those expected from an argon plasma at T=6000 K, indicating that collisions during ion extraction reduce the abundance of the MAr(2+) ions relative to the composition in the source. The corresponding singly charged MAr(+) ions are also observed but occur at about three orders of magnitude lower intensity than MAr(2+) . PMID:27252087

  14. Acoustically excited heated jets. 1: Internal excitation

    NASA Technical Reports Server (NTRS)

    Lepicovsky, J.; Ahuja, K. K.; Brown, W. H.; Salikuddin, M.; Morris, P. J.

    1988-01-01

    The effects of relatively strong upstream acoustic excitation on the mixing of heated jets with the surrounding air are investigated. To determine the extent of the available information on experiments and theories dealing with acoustically excited heated jets, an extensive literature survey was carried out. The experimental program consisted of flow visualization and flowfield velocity and temperature measurements for a broad range of jet operating and flow excitation conditions. A 50.8-mm-diam nozzle was used for this purpose. Parallel to the experimental study, an existing theoretical model of excited jets was refined to include the region downstream of the jet potential core. Excellent agreement was found between theory and experiment in moderately heated jets. However, the theory has not yet been confirmed for highly heated jets. It was found that the sensitivity of heated jets to upstream acoustic excitation varies strongly with the jet operating conditions and that the threshold excitation level increases with increasing jet temperature. Furthermore, the preferential Strouhal number is found not to change significantly with a change of the jet operating conditions. Finally, the effects of the nozzle exit boundary layer thickness appear to be similar for both heated and unheated jets at low Mach numbers.

  15. Method for exciting inductive-resistive loads with high and controllable direct current

    DOEpatents

    Hill, Jr., Homer M.

    1976-01-01

    Apparatus and method for transmitting dc power to a load circuit by applying a dc voltage from a standard waveform synthesizer to duration modulate a bipolar rectangular wave generator. As the amplitude of the dc voltage increases, the widths of the rectangular wave generator output pulses increase, and as the amplitude of the dc voltage decreases, the widths of the rectangular wave generator output pulses decrease. Thus, the waveform synthesizer selectively changes the durations of the rectangular wave generator bipolar output pulses so as to produce a rectangular wave ac carrier that is duration modulated in accordance with and in direct proportion to the voltage amplitude from the synthesizer. Thereupon, by transferring the carrier to the load circuit through an amplifier and a rectifier, the load current also corresponds directly to the voltage amplitude from the synthesizer. To this end, the rectified wave at less than 100% duty factor, amounts to a doubled frequency direct voltage pulse train for applying a direct current to the load, while the current ripple is minimized by a high L/R in the load circuit. In one embodiment, a power transmitting power amplifier means having a dc power supply is matched to the load circuit through a transformer for current magnification without sacrificing load current duration capability, while negative voltage and current feedback are provided in order to insure good output fidelity.

  16. The ultraviolet spectrum of a strongly reddened, high-excitation Herbig-Haro object

    NASA Technical Reports Server (NTRS)

    Bohm, K. H.; Bohm-Vitense, E.

    1984-01-01

    Short- and long-wavelength IUE spectra of the rather strongly reddened, high radial velocity Herbig-Haro object HH 32A have been obtained. The object is well known for its large positive radial velocity and for its unusually large velocity dispersion. In consequence of the large ultraviolet extinction, the spectra are faint. The semiforbidden C III 1909 and Mg II 2800 emission lines are, however, clearly detected, and their fluxes can be measured with reasonable accuracy. C IV 1550 and Si III 1892 are very probably present. The continuum can be detected convincingly in the wavelength range 1500-1900 A. In other regions it is just barely detectable. The continuum has an energy distribution which is probably very similar to that of HH 1 and HH 2H. If an average galactic extinction curve is used, the line fluxes for semiforbidden C III 1909 and C IV 1550 indicate a shock velocity of at least 140 km/s which is higher than for HH 1 or HH 2. If a Theta Ori-type extinction curve is used instead, ultraviolet line ratios are obtained which are rather similar to those in HH 1 and HH 2.

  17. High resolution IR diode laser study of collisional energy transfer between highly vibrationally excited monofluorobenzene and CO2: the effect of donor fluorination on strong collision energy transfer.

    PubMed

    Kim, Kilyoung; Johnson, Alan M; Powell, Amber L; Mitchell, Deborah G; Sevy, Eric T

    2014-12-21

    Collisional energy transfer between vibrational ground state CO2 and highly vibrationally excited monofluorobenzene (MFB) was studied using narrow bandwidth (0.0003 cm(-1)) IR diode laser absorption spectroscopy. Highly vibrationally excited MFB with E' = ∼41,000 cm(-1) was prepared by 248 nm UV excitation followed by rapid radiationless internal conversion to the electronic ground state (S1→S0*). The amount of vibrational energy transferred from hot MFB into rotations and translations of CO2 via collisions was measured by probing the scattered CO2 using the IR diode laser. The absolute state specific energy transfer rate constants and scattering probabilities for single collisions between hot MFB and CO2 were measured and used to determine the energy transfer probability distribution function, P(E,E'), in the large ΔE region. P(E,E') was then fit to a bi-exponential function and extrapolated to the low ΔE region. P(E,E') and the biexponential fit data were used to determine the partitioning between weak and strong collisions as well as investigate molecular properties responsible for large collisional energy transfer events. Fermi's Golden rule was used to model the shape of P(E,E') and identify which donor vibrational motions are primarily responsible for energy transfer. In general, the results suggest that low-frequency MFB vibrational modes are primarily responsible for strong collisions, and govern the shape and magnitude of P(E,E'). Where deviations from this general trend occur, vibrational modes with large negative anharmonicity constants are more efficient energy gateways than modes with similar frequency, while vibrational modes with large positive anharmonicity constants are less efficient at energy transfer than modes of similar frequency.

  18. Swept confocally-aligned planar excitation (SCAPE) microscopy for high-speed volumetric imaging of behaving organisms

    NASA Astrophysics Data System (ADS)

    Bouchard, Matthew B.; Voleti, Venkatakaushik; Mendes, César S.; Lacefield, Clay; Grueber, Wesley B.; Mann, Richard S.; Bruno, Randy M.; Hillman, Elizabeth M. C.

    2015-02-01

    We report a three-dimensional microscopy technique—swept, confocally-aligned planar excitation (SCAPE) microscopy—that allows volumetric imaging of living samples at ultrahigh speeds. Although confocal and two-photon microscopy have revolutionized biomedical research, current implementations are costly, complex and limited in their ability to image three-dimensional volumes at high speeds. Light-sheet microscopy techniques using two-objective, orthogonal illumination and detection require a highly constrained sample geometry and either physical sample translation or complex synchronization of illumination and detection planes. In contrast, SCAPE microscopy acquires images using an angled, swept light sheet in a single-objective, en face geometry. Unique confocal descanning and image rotation optics map this moving plane onto a stationary high-speed camera, permitting completely translationless three-dimensional imaging of intact samples at rates exceeding 20 volumes per second. We demonstrate SCAPE microscopy by imaging spontaneous neuronal firing in the intact brain of awake behaving mice, as well as freely moving transgenic Drosophila larvae.

  19. Parallel assessment of nutrition and activity in athletes: validation against doubly labelled water, 24-h urea excretion, and indirect calorimetry.

    PubMed

    Koehler, Karsten; Braun, Hans; De Marees, Markus; Fusch, Gerhard; Fusch, Christoph; Mester, Joachim; Schaenzer, Wilhelm

    2010-11-01

    The assessment of nutrition and activity in athletes requires accurate and precise methods. The aim of this study was to validate a protocol for parallel assessment of diet and exercise against doubly labelled water, 24-h urea excretion, and respiratory gas exchange. The participants were 14 male triathletes under normal training conditions. Energy intake and doubly labelled water were weakly associated with each other (r = 0.69, standard error of estimate [SEE] = 304 kcal x day(-1)). Protein intake was strongly correlated with 24-h urea (r = 0.89) but showed considerable individual variation (SEE = 0.34 g kg(-1) x day(-1)). Total energy expenditure based on recorded activities was highly correlated with doubly labelled water (r = 0.95, SEE = 195 kcal x day(-1)) but was proportionally biased. During running and cycling, estimated exercise energy expenditure was highly correlated with gas exchange (running: r = 0.89, SEE = 1.6 kcal x min(-1); cycling: r = 0.95, SEE = 1.4 kcal x min(-1)). High exercise energy expenditure was slightly underestimated during running. For nutrition data, variations appear too large for precise measurements in individual athletes, which is a common problem of dietary assessment methods. Despite the high correlations of total energy expenditure and exercise energy expenditure with reference methods, a correction for systematic errors is necessary for the valid estimation of energetic requirements in individual athletes. PMID:20967672

  20. Simple rate equation model for hypothetical doubly stimulated emission of both photons and phonons in quantum-well lasers

    SciTech Connect

    Kroemer, H.

    1981-06-15

    The dissipation processes by which electrons and holes lose energy after being trapped in quantum wells might, in a sufficiently heavily pumped quantum well laser, lead to the buildup of such a high phonon population that phonon-assisted laser action by doubly stimulated emission of photons and phonons acquires a higher gain than unassisted laser action. The resulting mode switching exhibits a pronounced hysteresis with pump rate, which should be a characteristic identifying feature of phonon-assisted laser action.

  1. Search for long-lived doubly charged Higgs bosons in pp collisions at sqrt[s] = 1.96 TeV.

    PubMed

    Acosta, D; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Ambrose, D; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arisawa, T; Arguin, J-F; Artikov, A; Ashmanskas, W; Attal, A; Azfar, F; Azzi-Bacchetta, P; Bacchetta, N; Bachacou, H; Badgett, W; Barbaro-Galtieri, A; Barker, G J; Barnes, V E; Barnett, B A; Baroiant, S; Bauer, G; Bedeschi, F; Behari, S; Belforte, S; Bellettini, G; Bellinger, J; Belloni, A; Ben-Haim, E; Benjamin, D; Beretvas, A; Bhatti, A; Binkley, M; Bisello, D; Bishai, M; Blair, R E; Blocker, C; Bloom, K; Blumenfeld, B; Bocci, A; Bodek, A; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Bourov, S; Brau, B; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Casarsa, M; Carlsmith, D; Carosi, R; Carron, S; Cavalli-Sforza, M; Castro, A; Catastini, P; Cauz, D; Cerri, A; Cerrito, L; Chapman, J; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Chuang, S; Chung, K; Chung, W-H; Chung, Y S; Cijliak, M; Ciobanu, C I; Ciocci, M A; Clark, A G; Clark, D; Coca, M; Connolly, A; Convery, M; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Cranshaw, J; Cuevas, J; Cruz, A; Culbertson, R; Currat, C; Cyr, D; Dagenhart, D; Da Ronco, S; D'Auria, S; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; Dell'Orso, M; Demers, S; Demortier, L; Deninno, M; De Pedis, D; Derwent, P F; Dionisi, C; Dittmann, J R; DiTuro, P; Dörr, C; Dominguez, A; Donati, S; Donega, M; Donini, J; D'Onofrio, M; Dorigo, T; Ebina, K; Efron, J; Ehlers, J; Erbacher, R; Erdmann, M; Errede, D; Errede, S; Eusebi, R; Fang, H-C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R D; Flanagan, G; Flores-Castillo, L R; Foland, A; Forrester, S; Foster, G W; Franklin, M; Freeman, J C; Fujii, Y; Furic, I; Gajjar, A; Gallinaro, M; Galyardt, J; Garcia-Sciveres, M; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D W; Gerchtein, E; Giagu, S; Giannetti, P; Gibson, A; Gibson, K; Ginsburg, C; Giolo, K; Giordani, M; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, D; Goldstein, J; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Gotra, Y; Goulianos, K; Gresele, A; Griffiths, M; Grosso-Pilcher, C; Grundler, U; da Costa, J Guimaraes; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Handler, R; Happacher, F; Hara, K; Hare, M; Harr, R F; Harris, R M; Hartmann, F; Hatakeyama, K; Hauser, J; Hays, C; Hayward, H; Heinemann, B; Heinrich, J; Hennecke, M; Herndon, M; Hill, C; Hirschbuehl, D; Hocker, A; Hoffman, K D; Holloway, A; Hou, S; Houlden, M A; Huffman, B T; Huang, Y; Hughes, R E; Huston, J; Ikado, K; Incandela, J; Introzzi, G; Iori, M; Ishizawa, Y; Issever, C; Ivanov, A; Iwata, Y; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jensen, H; Jeon, E J; Jones, M; Joo, K K; Jun, S Y; Junk, T; Kamon, T; Kang, J; Unel, M Karagoz; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, M S; Kim, S B; Kim, S H; Kim, Y K; Kirby, M; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kobayashi, H; Kong, D J; Kondo, K; Konigsberg, J; Kordas, K; Korn, A; Korytov, A; Kotwal, A V; Kovalev, A; Kraus, J; Kravchenko, I; Kreymer, A; Kroll, J; Kruse, M; Krutelyov, V; Kuhlmann, S E; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R; Lannon, K; Lath, A; Latino, G; Lauhakangas, R; Lazzizzera, I; Lecci, C; Lecompte, T; Lee, J; Lee, J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Li, K; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Liss, T M; Lister, A; Litvintsev, D O; Liu, T; Liu, Y; Lockyer, N S; Loginov, A; Loreti, M; Loverre, P; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Macqueen, D; Madrak, R; Maeshima, K; Maksimovic, P; Manca, G; Marginean, R; Marino, C; Martin, A; Martin, M; Martin, V; Martínez, M; Maruyama, T; Matsunaga, H; Mattson, M; Mazzanti, P; McFarland, K S; McGivern, D; McIntyre, P M; McNamara, P; McNulty, R; Mehta, A; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, L; Miller, R; Miller, J S; Mills, C; Miquel, R; Miscetti, S; Mitselmakher, G; Miyamoto, A; Moggi, N; Mohr, B; Moore, R; Morello, M; Fernandez, P A Movilla; Muelmenstaedt, J; Mukherjee, A; Mulhearn, M; Muller, T; Mumford, R; Munar, A; Murat, P; Nachtman, J; Nahn, S; Nakano, I; Napier, A; Napora, R; Naumov, D; Necula, V; Nielsen, J; Nelson, T; Neu, C; Neubauer, M S; Nigmanov, T; Nodulman, L; Norniella, O; Ogawa, T; Oh, S H; Oh, Y D; Ohsugi, T; Okusawa, T; Oldeman, R; Orava, R; Orejudos, W; Osterberg, K; Pagliarone, C; Palencia, E; Paoletti, R; Papadimitriou, V; Paramonov, A A; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pitts, K T; Plager, C; Pondrom, L; Pope, G; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pratt, T; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Rademacker, J; Rahaman, M A; Rakitine, A; Rappoccio, S; Ratnikov, F; Ray, H; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Rimondi, F; Rinnert, K; Ristori, L; Robertson, W J; Robson, A; Rodrigo, T; Rolli, S; Roser, R; Rossin, R; Rott, C; Russ, J; Rusu, V; Ruiz, A; Ryan, D; Saarikko, H; Sabik, S; Safonov, A; St Denis, R; Sakumoto, W K; Salamanna, G; Saltzberg, D; Sanchez, C; Santi, L; Sarkar, S; Sato, K; Savard, P; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Semeria, F; Sexton-Kennedy, L; Sfiligoi, I; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sill, A; Sinervo, P; Sisakyan, A; Sjolin, J; Skiba, A; Slaughter, A J; Sliwa, K; Smirnov, D; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S V; Spalding, J; Spezziga, M; Spinella, F; Squillacioti, P; Stadie, H; Stanitzki, M; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sumorok, K; Sun, H; Suzuki, T; Taffard, A; Tafirout, R; Takano, H; Takashima, R; Takeuchi, Y; Takikawa, K; Tanaka, M; Tanaka, R; Tanimoto, N; Tecchio, M; Teng, P K; Terashi, K; Tesarek, R J; Tether, S; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tollefson, K; Tomura, T; Tonelli, D; Tönnesmann, M; Torre, S; Torretta, D; Trischuk, W; Tsuchiya, R; Tsuno, S; Tsybychev, D; Turini, N; Tuttle, J; Ukegawa, F; Unverhau, T; Uozumi, S; Usynin, D; Vacavant, L; Vaiciulis, A; Varganov, A; Vejcik, S; Velev, G; Veszpremi, V; Veramendi, G; Vickey, T; Vidal, R; Vila, I; Vilar, R; Vollrath, I; Volobouev, I; von der Mey, M; Wagner, P; Wagner, R G; Wagner, R L; Wagner, W; Wallny, R; Walter, T; Wan, Z; Wang, M J; Wang, S M; Warburton, A; Ward, B; Waschke, S; Waters, D; Watts, T; Weber, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wolter, M; Worcester, M; Worm, S; Wright, T; Wu, X; Würthwein, F; Wyatt, A; Yagil, A; Yamashita, T; Yamamoto, K; Yamaoka, J; Yang, C; Yang, U K; Yao, W; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, I; Yu, S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zetti, F; Zhou, J; Zucchelli, S

    2005-08-12

    We present a search for long-lived doubly charged Higgs bosons (H(+/- +/-)), with signatures of high ionization energy loss and muonlike penetration. We use 292 pb(-1) of data collected in pp collisions at sqrt[s] = 1.96 TeV by the CDF II detector at the Fermilab Tevatron. Observing no evidence of long-lived doubly charged particle production, we exclude H(+/- +/-)(L) and H(+/- +/-)(R) bosons with masses below 133 GeV/c(2) and 109 GeV/c(2), respectively. In the degenerate case we exclude H(+/- +/-) mass below 146 GeV/c(2). All limits are quoted at the 95% confidence level.

  2. Doubly-charged ions in the planetary ionospheres: a review.

    PubMed

    Thissen, Roland; Witasse, Olivier; Dutuit, Odile; Wedlund, Cyril Simon; Gronoff, Guillaume; Lilensten, Jean

    2011-11-01

    This paper presents a review of the current knowledge on the doubly-charged atomic and molecular positive ions in the planetary atmospheres of the Solar System. It is focused on the terrestrial planets which have a dense atmosphere of N(2) or CO(2), i.e. Venus, the Earth and Mars, but also includes Titan, the largest satellite of Saturn, which has a dense atmosphere composed mainly of N(2) and a few percent of methane. Given the composition of these neutral atmospheres, the following species are considered: C(++), N(++), O(++), CH(4)(++), CO(++), N(2)(++), NO(++), O(2)(++), Ar(++) and CO(2)(++). We first discuss the status of their detection in the atmospheres of planets. Then, we provide a comprehensive review of their complex and original photochemistry, production and loss processes. Synthesis tables are provided for those ions, while a discussion on individual species is also provided. Methods for detecting doubly-charged ions in planetary atmospheres are presented, namely with mass-spectrometry, remote sensing and fine plasma density measurements. A section covers some original applications, like the possible effect of the presence of doubly-charged ions on the escape of an atmosphere, which is a key topic of ongoing planetary exploration, related to the evolution of a planet. The results of models, displayed in a comparative way for Venus, Earth, Mars and Titan, are discussed, as they can predict the presence of doubly-charged ions and will certainly trigger new investigations. Finally we give our view concerning next steps, challenges and needs for future studies, hoping that new scientific results will be achieved in the coming years and feed the necessary interdisciplinary exchanges amongst different scientific communities. PMID:21931881

  3. Influence of curvature on the losses of doubly clad fibers.

    PubMed

    Marcuse, D

    1982-12-01

    The loss increase of the HE(11) mode of a doubly clad (depressed-index) fiber due to constant curvature is considered. The calculations presented in this paper are based on a simplified theory. We find that for typical fibers the leakage loss of the HE(11) mode begins to increase significantly when the radius of curvature of the fiber axis reaches the 1-10-cm range.

  4. Alternating parity structure in doubly odd /sup 218/Ac

    SciTech Connect

    Debray, M.E.; Davidson, M.; Kreiner, A.J.; Davidson, J.; Falcone, G.; Hojman, D.; Santos, D.

    1989-03-01

    States in doubly odd /sup 218/Ac have been studied using in-beam ..cap alpha..-, ..gamma..-, and e/sup -/-spectroscopy techniques mainly through the /sup 209/Bi(/sup 12/C,3n)= fusion-evaporation reaction. /sup 218/Ac shows a band structure, with interleaved states of alternating parities connected by enhanced B(E1) transitions, which is strikingly similar to the one in its isotone /sup 217/Ra.

  5. Doubly curved nanofiber-reinforced optically transparent composites

    PubMed Central

    Shams, Md. Iftekhar; Yano, Hiroyuki

    2015-01-01

    Doubly curved nanofiber-reinforced optically transparent composites with low thermal expansion of 15 ppm/k are prepared by hot pressing vacuum-filtered Pickering emulsions of hydrophobic acrylic resin monomer, hydrophilic chitin nanofibers and water. The coalescence of acrylic monomer droplets in the emulsion is prevented by the chitin nanofibers network. This transparent composite has 3D shape moldability, making it attractive for optical precision parts. PMID:26552990

  6. Doubly curved nanofiber-reinforced optically transparent composites

    NASA Astrophysics Data System (ADS)

    Shams, Md. Iftekhar; Yano, Hiroyuki

    2015-11-01

    Doubly curved nanofiber-reinforced optically transparent composites with low thermal expansion of 15 ppm/k are prepared by hot pressing vacuum-filtered Pickering emulsions of hydrophobic acrylic resin monomer, hydrophilic chitin nanofibers and water. The coalescence of acrylic monomer droplets in the emulsion is prevented by the chitin nanofibers network. This transparent composite has 3D shape moldability, making it attractive for optical precision parts.

  7. Excited-state dynamics of guanosine in aqueous solution revealed by time-resolved photoelectron spectroscopy: experiment and theory.

    PubMed

    Buchner, Franziska; Heggen, Berit; Ritze, Hans-Hermann; Thiel, Walter; Lübcke, Andrea

    2015-12-21

    Time-resolved photoelectron spectroscopy is performed on aqueous guanosine solution to study its excited-state relaxation dynamics. Experimental results are complemented by surface hopping dynamic simulations and evaluation of the excited-state ionization energy by Koopmans' theorem. Two alternative models for the relaxation dynamics are discussed. The experimentally observed excited-state lifetime is about 2.5 ps if the molecule is excited at 266 nm and about 1.1 ps if the molecule is excited at 238 nm. The experimental probe photon energy dependence of the photoelectron kinetic energy distribution suggests that the probe step is not vertical and involves a doubly-excited autoionizing state.

  8. Doubly sensitivity-enhanced 3D TOCSY-HSQC.

    PubMed

    Wijmenga, S S; van Mierlo, C P; Steensma, E

    1996-10-01

    Recently, strategies for double sensitivity enhancement in heteronuclear three-dimensional NMR experiments were introduced (Krishnamurthy, V.V. (1995) J. Magn. Reson., B106, 170-177; Sattler et al. (1995) J. Biomol. NMR, 6, 11-22; Sattler et al. (1995) J. Magn. Reson., B108, 235-242). Since a sensitivity enhancement of a factor 2(1/2) can be achieved for each indirect dimension, nD spectra can theoretically be enhanced up to a factor of 2(((n-1)/2)). We propose and analyze a doubly enhanced three-dimensional TOCSY-HSQC sequence. The application of the doubly enhanced three-dimensional {(15)N, (1)H} TOCSY-HSQC sequence is shown for uniformly (13)C-/(15)N- and (15)N-labeled samples of the relatively large Azotobacter vinelandii flavodoxin II (179 amino acids). The main factors that contribute to the final signal-to-noise enhancement have been systematically investigated. The sensitivity enhancement obtained for the doubly enhanced TOCSY-HSQC pulse sequence as compared to the standard (unenhanced) version is close to the theoretically expected factor of two.

  9. Characterization of the multifragment decay channel in highly excited nuclei. Progress report, March 15, 1992--September 14, 1993

    SciTech Connect

    de Souza, R.T.

    1992-10-01

    Characteristics of multifragment decay in heavy-ion induced reactions at intermediate energies are explored. Evolution of the timescale for emission of intermediate mass fragments (IMF: 3{le}Z{le}20) is investigated. Fragments associated with central collisions in the reactions {sup 36}Ar + {sup 197}Au at E/A = 50, 80, and 110 MeV are emitted on an extremely fast timescale, {tau} {le} 75 fm/c, comparable to the transit time of the projectile past the target nucleus. With increasing incident energy, mean fragment emission times decrease, consistent with statistical decay from highly excited systems or fast dynamical processes. To examine the importance of expansion effects in multifragmentation, the transverse kinetic energy of fragments was investigated. Evidence for expansion effects in the system {sup 36}Ar + {sup 197}Au at E/A = 50, 80, and 110 MeV was indicated by the charge dependence of the mean isotropic kinetic energy. At the highest incident energy the data suggest the onset of volume emission. Construction and performance of low-threshold high-resolution detector telescopes is discussed. Three-body Coulomb trajectory calculations are being used to probe kinematical correlations associated with neck emission of IMFs during fission. Initial design and testing of position sensitive parallel plate avalanche counters for upcoming ternary fission experiments is discussed.

  10. Resonant Spin Excitation in the High Temperature Superconductor Ba0.6K0.4Fe2As2

    SciTech Connect

    Christianson, Andrew D; Goremychkin, E. A.; Osborn, R.; Rosenkranz, Stephen; Lumsden, Mark D; Malliakas, C.; Todorov, L.; Claus, H.; Chung, D.Y.; Kanatzidis, M.; Bewley, Robert I.; Guidi, T.

    2008-12-18

    A new family of superconductors containing layers of iron arsenide has attracted considerable interest because of their high transition temperatures (T{sub c}), some of which are >50 K, and because of similarities with the high-{sub c} copper oxide superconductors. In both the iron arsenides and the copper oxides, superconductivity arises when an antiferromagnetically ordered phase has been suppressed by chemical doping. A universal feature of the copper oxide superconductors is the existence of a resonant magnetic excitation, localized in both energy and wavevector, within the superconducting phase. This resonance, which has also been observed in several heavy-fermion superconductors is predicted to occur when the sign of the superconducting energy gap takes opposite values on different parts of the Fermi surface, an unusual gap symmetry which implies that the electron pairing interaction is repulsive at short range. Angle-resolved photoelectron spectroscopy shows no evidence of gap anisotropy in the iron arsenides, but such measurements are insensitive to the phase of the gap on separate parts of the Fermi surface. Here we report inelastic neutron scattering observations of a magnetic resonance below T{sub c} in Ba{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2}, a phase-sensitive measurement demonstrating that the superconducting energy gap has unconventional symmetry in the iron arsenide superconductors.

  11. Measurement of Absolute Excitation Cross Sections in Highly-Charged Ions Using Electron Energy Loss and Merged Beams

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Smith, Steven J.; Lozano, J.

    2002-01-01

    There is increasing emphasis during this decade on understanding energy balance and phenomena observed in high electron temperature plasmas. The UV spectral return from FUSE, the X-ray spectral return from the HETG on Chandra and the LETGS 011 XMM-Newton are just beginning. Line emissions are almost entirely from highly-charged ions (HCIs) of C, N, 0, Ne, Mg, S, Si, Ca, and Fe. The Constellation-X mission will provide X-ray spectroscopy up to photon energies of 0.12 nm (10 keV) where primary line emitters will be HCIs. A variety of atomic parameters are required to model the stellar and solar plasma. These include cross sections for excitation, ionization, charge-exchange, X-ray emission, direct and indirect recombination, lifetimes and branching ratios, and dependences on l, m mixing by external E and B fields. In almost all cases the atomic quantities are calculated, and few comparisons to experiment have been carried out. Collision strengths and Einstein A-values are required to convert the observed spectral intensities to electron temperatures and densities in the stellar plasma. The JPL electron energy-loss and merged beam approach has been used to measure absolute collision strengths in a number of ions, with critical comparison made to the best available theories.

  12. Semiempirical Modeling of Ag Nanoclusters: New Parameters for Optical Property Studies Enable Determination of Double Excitation Contributions to Plasmonic Excitation.

    PubMed

    Gieseking, Rebecca L; Ratner, Mark A; Schatz, George C

    2016-07-01

    Quantum mechanical studies of Ag nanoclusters have shown that plasmonic behavior can be modeled in terms of excited states where collectivity among single excitations leads to strong absorption. However, new computational approaches are needed to provide understanding of plasmonic excitations beyond the single-excitation level. We show that semiempirical INDO/CI approaches with appropriately selected parameters reproduce the TD-DFT optical spectra of various closed-shell Ag clusters. The plasmon-like states with strong optical absorption comprise linear combinations of many singly excited configurations that contribute additively to the transition dipole moment, whereas all other excited states show significant cancellation among the contributions to the transition dipole moment. The computational efficiency of this approach allows us to investigate the role of double excitations at the INDO/SDCI level. The Ag cluster ground states are stabilized by slight mixing with doubly excited configurations, but the plasmonic states generally retain largely singly excited character. The consideration of double excitations in all cases improves the agreement of the INDO/CI absorption spectra with TD-DFT, suggesting that the SDCI calculation effectively captures some of the ground-state correlation implicit in DFT. These results provide the first evidence to support the commonly used assumption that single excitations are in many cases sufficient to describe the optical spectra of plasmonic excitations quantum mechanically.

  13. Suppression and nonlinear excitation of parasitic modes in second harmonic gyrotrons operating in a very high order mode

    SciTech Connect

    Nusinovich, Gregory S.; Pu, Ruifeng; Granatstein, Victor L.

    2015-07-06

    In recent years, there was an active development of high-power, sub-terahertz (sub-THz) gyrotrons for numerous applications. For example, a 0.67 THz gyrotron delivering more than 200 kW with about 20% efficiency was developed. This record high efficiency was achieved because the gyrotron operated in a high-order TE{sub 31,8}-mode with the power of ohmic losses less than 10% of the power of outgoing radiation. That gyrotron operated at the fundamental cyclotron resonance, and a high magnetic field of about 27 T was created by a pulse solenoid. For numerous applications, it is beneficial to use gyrotrons at cyclotron harmonics which can operate in available cryomagnets with fields not exceeding 15 T. However, typically, the gyrotron operation at harmonics faces severe competition from parasitic modes at the fundamental resonance. In the present paper, we consider a similar 0.67 THz gyrotron designed for operation in the same TE{sub 31,8}-mode, but at the second harmonic. We focus on two nonlinear effects typical for interaction between the fundamental and second harmonic modes, viz., the mode suppression and the nonlinear excitation of the mode at the fundamental harmonic by the second harmonic oscillations. Our study includes both the analytical theory and numerical simulations performed with the self-consistent code MAGY. The simulations show that stable second harmonic operation in the TE{sub 31,8} mode is possible with only modest sacrifice of efficiency and power.

  14. Probing the excited state properties of the highly phosphorescent Pt(dpyb)Cl compound by high-resolution optical spectroscopy.

    PubMed

    Rausch, Andreas F; Murphy, Lisa; Williams, J A Gareth; Yersin, Hartmut

    2009-12-01

    Detailed photophysical studies of the emitting triplet state of the highly phosphorescent compound Pt(dpyb)Cl based on high-resolution optical spectroscopy at cryogenic temperatures are presented {dpyb = N--C(2)--N-coordinated 1,3-di(pyridylbenzene)}. The results reveal a total zero-field splitting of the emitting triplet state T(1) of 10 cm(-1) and relatively short individual decay times for the two higher lying T(1) substates II and III, while the decay time of the lowest substate I is distinctly longer. Further evidence for the assignment of the T(1) substates is gained by emission measurements under high magnetic fields. Distinct differences are observed in the vibrational satellite structures of the emissions from the substates I and II, which are dominated by Herzberg-Teller and Franck-Condon activity, respectively. At T = 1.2 K, the individual spectra of these two substates can be separated by time-resolved spectroscopy. For the most prominent Franck-Condon active modes, Huang-Rhys parameters of S approximately 0.1 can be determined, which are characteristic of very small geometry rearrangements between the singlet ground state and the triplet state T(1). The similar geometries are ascribed to the high rigidity of the Pt(N--C--N) system which, unlike complexes incorporating bidentate phenylpyridine-type ligands and exhibiting similar metal-to-ligand charge transfer admixtures, cannot readily distort from planarity. The results provide new insight into strategies for optimizing the performance of platinum-based emitters for applications such as organic light-emitting diode (OLED) technology and imaging.

  15. Resolving shocked and UV excited components of H2 emission in planetary nebulae with high-resolution near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Kaplan, Kyle; Dinerstein, Harriet L.; Jaffe, Daniel Thomas

    2016-06-01

    Planetary nebulae (PNe) form when low and intermediate-mass stars eject their outer layers into the ISM at the end of the AGB phase. Many PNe exhibit near-infrared (NIR) emission from molecular hydrogen (H2). This NIR emission arises from radiative decay out of excited rotation-vibration (rovibrational) states. The rovibrational states can be populated by excitation to higher electronic states through absorption of a far-UV photon followed by a radiative cascade to the electronic ground state, or by collisions (e.g., in a hot gas). The two processes populate the rovibrational levels of H2 differently, so the observed emergent emission spectrum provides an effective probe of the mechanisms that excite the H2. Many PNe display line intensity ratios that are intermediate between these two processes (Otsuka et al. 2013). With the advantages of the high spectral resolution (R~40000), broad wavelength coverage (1.45-2.45 μm), and high spatial resolution of the Immersion GRating Infrared Spectrometer (IGRINS, Park et al. 2014), we are able to differentiate components in position-velocity space: we see a slowly expanding UV-excited H2 shell in the PN M 1-11 and two faster moving “bullets” of thermalized H2 that we interpret as shocked gas from a bipolar outflow. We also present observations of several other PNe that exhibit similar morphologies of thermalized and UV-excited H2 components.

  16. Coulomb Excitation of Neutron-Rich Cd Isotopes at REX-ISOLDE

    SciTech Connect

    Kroell, Th.; Behrens, T.; Kruecken, R.; Faestermann, T.; Gernhaeuser, R.; Mahgoub, M.; Maierbeck, P.; Habs, D.; Kester, O.; Lutter, R.; Morgan, T.; Pasini, M.; Rudolph, K.; Thirolf, P.; Bildstein, V.; Niedermaier, O.; Scheit, H.; Schwalm, D.; Martin, D.; Warr, N.

    2005-11-21

    We report on the 'safe' Coulomb excitation of neutron-rich Cd isotopes in the vicinity of the doubly magic nucleus 132Sn. The radioactive nuclei have been produced by ISOLDE at CERN and postaccelerated by the REX-ISOLDE facility. The {gamma}-decay of excited states has been detected by the MINIBALL array. Preliminary results for the B(E2) values of 122,124Cd are consistent with expectations from phenomenological systematics.

  17. Vibrational spectra and intramolecular vibrational redistribution in highly excited deuterobromochlorofluoromethane CDBrClF: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Beil, Andreas; Hollenstein, Hans; Monti, Oliver L. A.; Quack, Martin; Stohner, Jürgen

    2000-08-01

    The rovibrational spectra of deuterobromochlorofluoromethane (CDBrClF) were measured at intermediate (0.1 cm-1) and high resolution (0.0024 cm-1 full bandwidth, half-maximum) by interferometric Fourier transform infrared spectroscopy in the range from the far infrared at 200 cm-1 to the near infrared (12 000 cm-1) covering all the fundamentals and CD stretching overtones up to polyad N=5. The spectra are completely analyzed in terms of their vibrational assignments to fundamentals, combinations and overtones. At high excitation the analysis reveals the dominant anharmonic coupling between four high frequency vibrational modes; the CD stretching (ν1), two CD bending (ν2,ν3), and the CF stretching mode (ν4). The analysis is carried out using effective model Hamiltonians including three and four vibrational degrees of freedom. We also present vibrational variational calculations on a grid in a four-dimensional normal coordinate subspace. The potential energy and the dipole moment function are calculated ab initio on this grid using self-consistent field second order Møller-Plesset perturbation theory (MP2). Experimental and theoretical results for band positions and integrated intensities as well as effective spectroscopic parameters are found to be in good agreement. The important anharmonic coupling between the CD chromophore and the CF stretching vibration can be described by an effective cubic Fermi resonance coupling constant ksff'≈(50±10) cm-1, which leads to intramolecular vibrational redistribution between the CD and CF chromophores on the femtosecond time scale. Time dependent intramolecular vibrational redistribution processes in CDBrClF are derived in various representations, including time dependent probability densities ("wave packets") in coordinate space and finally time dependent entropy.

  18. A New Equivalence Theory Method for Treating Doubly Heterogeneous Fuel - I. Theory

    SciTech Connect

    Williams, Mark L.; Lee, Deokjung; Choi, Sooyoung

    2015-03-04

    A new methodology has been developed to treat resonance self-shielding in doubly heterogeneous very high temperature gas-cooled reactor systems in which the fuel compact region of a reactor lattice consists of small fuel grains dispersed in a graphite matrix. This new method first homogenizes the fuel grain and matrix materials using an analytically derived disadvantage factor from a two-region problem with equivalence theory and intermediate resonance method. This disadvantage factor accounts for spatial self-shielding effects inside each grain within the framework of an infinite array of grains. Then the homogenized fuel compact is self-shielded using a Bondarenko method to account for interactions between the fuel compact regions in the fuel lattice. In the final form of the equations for actual implementations, the double-heterogeneity effects are accounted for by simply using a modified definition of a background cross section, which includes geometry parameters and cross sections for both the grain and fuel compact regions. With the new method, the doubly heterogeneous resonance self-shielding effect can be treated easily even with legacy codes programmed only for a singly heterogeneous system by simple modifications in the background cross section for resonance integral interpolations. This paper presents a detailed derivation of the new method and a sensitivity study of double-heterogeneity parameters introduced during the derivation. The implementation of the method and verification results for various test cases are presented in the companion paper.

  19. A New Equivalence Theory Method for Treating Doubly Heterogeneous Fuel - I. Theory

    DOE PAGESBeta

    Williams, Mark L.; Lee, Deokjung; Choi, Sooyoung

    2015-03-04

    A new methodology has been developed to treat resonance self-shielding in doubly heterogeneous very high temperature gas-cooled reactor systems in which the fuel compact region of a reactor lattice consists of small fuel grains dispersed in a graphite matrix. This new method first homogenizes the fuel grain and matrix materials using an analytically derived disadvantage factor from a two-region problem with equivalence theory and intermediate resonance method. This disadvantage factor accounts for spatial self-shielding effects inside each grain within the framework of an infinite array of grains. Then the homogenized fuel compact is self-shielded using a Bondarenko method to accountmore » for interactions between the fuel compact regions in the fuel lattice. In the final form of the equations for actual implementations, the double-heterogeneity effects are accounted for by simply using a modified definition of a background cross section, which includes geometry parameters and cross sections for both the grain and fuel compact regions. With the new method, the doubly heterogeneous resonance self-shielding effect can be treated easily even with legacy codes programmed only for a singly heterogeneous system by simple modifications in the background cross section for resonance integral interpolations. This paper presents a detailed derivation of the new method and a sensitivity study of double-heterogeneity parameters introduced during the derivation. The implementation of the method and verification results for various test cases are presented in the companion paper.« less

  20. Ionization Efficiency of Doubly Charged Ions Formed from Polyprotic Acids in Electrospray Negative Mode

    NASA Astrophysics Data System (ADS)

    Liigand, Piia; Kaupmees, Karl; Kruve, Anneli

    2016-07-01

    The ability of polyprotic acids to give doubly charged ions in negative mode electrospray was studied and related to physicochemical properties of the acids via linear discriminant analysis (LDA). It was discovered that the compound has to be strongly acidic (low p K a1 and p K a2) and to have high hydrophobicity (log P ow) to become multiply charged. Ability to give multiply charged ions in ESI/MS cannot be directly predicted from the solution phase acidities. Therefore, for the first time, a quantitative model to predict the charge state of the analyte in ESI/MS is proposed and validated for small anions. Also, a model to predict ionization efficiencies of these analytes was developed. Results indicate that acidity of the analyte, its octanol-water partition coefficient, and charge delocalization are important factors that influence ionization efficiencies as well as charge states of the analytes. The pH of the solvent was also found to be an important factor influencing the ionization efficiency of doubly charged ions.

  1. Collisional Energy Transfer between Highly Vibrationally Excited CsH(X1Σ+, v = 15-22) and H2

    NASA Astrophysics Data System (ADS)

    Zhu, Dong-Hui; Zhang, Bin; Shen, Yi-Fan; Dai, Kang

    2011-09-01

    The Cs atoms are prepared in the 6D state by two-photon absorption. CsH(X1Σ+, v″=0) is generated from the Cs(6D)+H2 reaction. By overtone excitation with a pulsed dye laser, highly vibrational states v″ >= 15 of CsH in its ground electronic state are obtained. A diode laser is used to probe either the prepared vibrational state or the collisionally populated states. The decay signal of the time-resolved fluorescence from the A1Σ+(v') → X1Σ+(v″) transition is monitored. Based on the Stern—Volmer equation, the total rate coefficients for v″ = 15-22 are yielded. The time evolution and relative intensities of three related states, v″, v″ - 1 and v″ - 2, made by the initially prepared v″ state of CsH are measured. Rate coefficients of single- and double-quantum relaxation are obtained. These results show that single-quantum relaxation accounts for >=50% of the total relaxation out of states v″=17-20. Multiquantum relaxation (Δv>=2) makes major contribution (>=62%) to the vibrational relaxation at v″=21 and 22. A simple explanation is given.

  2. Absolute optical oscillator strengths for the electronic excitation of atoms at high resolution: Experimental methods and measurements for helium

    SciTech Connect

    Chan, W.F.; Cooper, G.; Brion, C.E. )

    1991-07-01

    An alternative method is described for the measurement of absolute optical oscillator strengths (cross sections) for electronic excitation of free atoms and molecules throughout the discrete region of the valence-shell spectrum at high energy resolution (full width at half maximum of 0.048 eV). The technique, utilizing the virtual-photon field of a fast electron inelastically scattered at negligible momentum transfer, avoids many of the difficulties associated with the various direct optical techniques that have traditionally been used for absolute optical oscillator strength measurements. The method is also free of the bandwidth (line saturation) effects that can seriously limit the accuracy of photoabsorption cross-section measurements for discrete transitions of narrow linewidth obtained using the Beer-Lambert law ({ital I}{sub 0}/{ital I}=exp({ital nl}{sigma}{sub {ital p}})). Since the line-saturation effects are not widely appreciated and are only usually considered in the context of peak heights, a detailed analysis of this problem is presented, with consideration of the integrated cross section (oscillator strength) over the profile of each discrete peak.

  3. Excitation of atoms and molecules in collisions with highly charged ions. [Cyclotron Inst. , Texas A M Univ. , College Station, Texas

    SciTech Connect

    Watson, R.L.

    1993-01-01

    A study of the double ionization of He by high-energy N[sup 7+] ions was extended up in energy to 40 MeV/amu. Coincidence time-of-flight studies of multicharged N[sub 2], O[sub 2], and CO molecular ions produced in collisions with 97-MeV Ar[sup 14+] ions were completed. Analysis of the total kinetic energy distributions and comparison with the available data for CO[sup 2+] and CO[sup 3+] from synchrotron radiation experiments led to the conclusion that ionization by Ar-ion impact populates states having considerably higher excitation energies than those accessed by photoionization. The dissociation fractions for CO[sup 1+] and CO[sup 2+] molecular ions, and the branching ratios for the most prominent charge division channels of CO[sup 2+] through CO[sup 7+] were determined from time-of-flight singles and coincidence data. An experiment designed to investigate the orientation dependence of dissociative multielectron ionization of molecules by heavy ion impact was completed. Measurements of the cross sections for K-shell ionization of intermediate-Z elements by 30-MeV/amu H, N, Ne, and Ar ions were completed. The cross sections were determined for solid targets of Z = 13, 22, 26, 29, 32, 40, 42, 46, and 50 by recording the spectra of K x rays with a Si(Li) spectrometer.

  4. Excitation of atoms and molecules in collisions with highly charged ions. Progress report, January 1, 1990--December 1, 1992

    SciTech Connect

    Watson, R.L.

    1993-01-01

    A study of the double ionization of He by high-energy N{sup 7+} ions was extended up in energy to 40 MeV/amu. Coincidence time-of-flight studies of multicharged N{sub 2}, O{sub 2}, and CO molecular ions produced in collisions with 97-MeV Ar{sup 14+} ions were completed. Analysis of the total kinetic energy distributions and comparison with the available data for CO{sup 2+} and CO{sup 3+} from synchrotron radiation experiments led to the conclusion that ionization by Ar-ion impact populates states having considerably higher excitation energies than those accessed by photoionization. The dissociation fractions for CO{sup 1+} and CO{sup 2+} molecular ions, and the branching ratios for the most prominent charge division channels of CO{sup 2+} through CO{sup 7+} were determined from time-of-flight singles and coincidence data. An experiment designed to investigate the orientation dependence of dissociative multielectron ionization of molecules by heavy ion impact was completed. Measurements of the cross sections for K-shell ionization of intermediate-Z elements by 30-MeV/amu H, N, Ne, and Ar ions were completed. The cross sections were determined for solid targets of Z = 13, 22, 26, 29, 32, 40, 42, 46, and 50 by recording the spectra of K x rays with a Si(Li) spectrometer.

  5. High-frequency stimulation-induced peptide release synchronizes arcuate kisspeptin neurons and excites GnRH neurons

    PubMed Central

    Qiu, Jian; Nestor, Casey C; Zhang, Chunguang; Padilla, Stephanie L; Palmiter, Richard D

    2016-01-01

    Kisspeptin (Kiss1) and neurokinin B (NKB) neurocircuits are essential for pubertal development and fertility. Kisspeptin neurons in the hypothalamic arcuate nucleus (Kiss1ARH) co-express Kiss1, NKB, dynorphin and glutamate and are postulated to provide an episodic, excitatory drive to gonadotropin-releasing hormone 1 (GnRH) neurons, the synaptic mechanisms of which are unknown. We characterized the cellular basis for synchronized Kiss1ARH neuronal activity using optogenetics, whole-cell electrophysiology, molecular pharmacology and single cell RT-PCR in mice. High-frequency photostimulation of Kiss1ARH neurons evoked local release of excitatory (NKB) and inhibitory (dynorphin) neuropeptides, which were found to synchronize the Kiss1ARH neuronal firing. The light-evoked synchronous activity caused robust excitation of GnRH neurons by a synaptic mechanism that also involved glutamatergic input to preoptic Kiss1 neurons from Kiss1ARH neurons. We propose that Kiss1ARH neurons play a dual role of driving episodic secretion of GnRH through the differential release of peptide and amino acid neurotransmitters to coordinate reproductive function. DOI: http://dx.doi.org/10.7554/eLife.16246.001 PMID:27549338

  6. High-frequency stimulation-induced peptide release synchronizes arcuate kisspeptin neurons and excites GnRH neurons.

    PubMed

    Qiu, Jian; Nestor, Casey C; Zhang, Chunguang; Padilla, Stephanie L; Palmiter, Richard D; Kelly, Martin J; Rønnekleiv, Oline K

    2016-01-01

    Kisspeptin (Kiss1) and neurokinin B (NKB) neurocircuits are essential for pubertal development and fertility. Kisspeptin neurons in the hypothalamic arcuate nucleus (Kiss1(ARH)) co-express Kiss1, NKB, dynorphin and glutamate and are postulated to provide an episodic, excitatory drive to gonadotropin-releasing hormone 1 (GnRH) neurons, the synaptic mechanisms of which are unknown. We characterized the cellular basis for synchronized Kiss1(ARH) neuronal activity using optogenetics, whole-cell electrophysiology, molecular pharmacology and single cell RT-PCR in mice. High-frequency photostimulation of Kiss1(ARH) neurons evoked local release of excitatory (NKB) and inhibitory (dynorphin) neuropeptides, which were found to synchronize the Kiss1(ARH) neuronal firing. The light-evoked synchronous activity caused robust excitation of GnRH neurons by a synaptic mechanism that also involved glutamatergic input to preoptic Kiss1 neurons from Kiss1(ARH) neurons. We propose that Kiss1(ARH) neurons play a dual role of driving episodic secretion of GnRH through the differential release of peptide and amino acid neurotransmitters to coordinate reproductive function. PMID:27549338

  7. Excitation of atoms and molecules in collisions with highly charged ions. Progress report, January 1, 1991--March 1, 1992

    SciTech Connect

    Watson, R.L.

    1992-03-01

    This report discusses research of multicharged nitrogen, oxygen and carbon monoxide molecular ions produced with collision with multicharged argon ions. Properties like ionization, dissociation, and excitation are investigated. (LSP)

  8. The CHESS survey of the L1157-B1 bow-shock: high and low excitation water vapor

    NASA Astrophysics Data System (ADS)

    Busquet, G.; Lefloch, B.; Benedettini, M.; Ceccarelli, C.; Codella, C.; Cabrit, S.; Nisini, B.; Viti, S.; Gómez-Ruiz, A. I.; Gusdorf, A.; di Giorgio, A. M.; Wiesenfeld, L.

    2014-01-01

    Context. Molecular outflows powered by young protostars strongly affect the kinematics and chemistry of the natal molecular cloud through strong shocks. This results in substantial modifications of the abundance of several species. In particular, water is a powerful tracer of shocked material because of its sensitivity to both physical conditions and chemical processes. Aims: As part of the Chemical HErschel Surveys of Star-forming regions (CHESS) guaranteed time key program, we aim at investigating the physical and chemical conditions of H2O in the brightest shock region B1 of the L1157 molecular outflow. Methods: We observed several ortho- and para-H2O transitions using the HIFI and PACS instruments on board Herschel toward L1157-B1, providing a detailed picture of the kinematics and spatial distribution of the gas. We performed a large velocity gradient (LVG) analysis to derive the physical conditions of H2O shocked material, and ultimately obtain its abundance. Results: We detected 13 H2O lines with both instruments probing a wide range of excitation conditions. This is the largest data set of water lines observed in a protostellar shock and it provides both the kinematics and the spatial information of the emitting gas. The PACS maps reveal that H2O traces weak and extended emission associated with the outflow identified also with HIFI in the o-H2O line at 556.9 GHz, and a compact (~10'') bright, higher excitation region. The LVG analysis of H2O lines in the bow-shock show the presence of two gas components with different excitation conditions: a warm (Tkin ≃ 200-300 K) and dense (n(H2) ≃ (1-3) × 106 cm-3) component with an assumed extent of 10'', and a compact (~2''-5'') and hot, tenuous (Tkin ≃ 900-1400 K, n(H2) ≃ 103-4 cm-3) gas component that is needed to account for the line fluxes of high Eu transitions. The fractional abundance of the warm and hot H2O gas components is estimated to be (0.7-2) × 10-6 and (1-3) × 10-4, respectively. Finally, we

  9. The mutable nature of particle-core excitations with spin in the one-valence-proton nucleus 133Sb

    NASA Astrophysics Data System (ADS)

    Bocchi, G.; Leoni, S.; Fornal, B.; Colò, G.; Bortignon, P. F.; Bottoni, S.; Bracco, A.; Michelagnoli, C.; Bazzacco, D.; Blanc, A.; de France, G.; Jentschel, M.; Köster, U.; Mutti, P.; Régis, J.-M.; Simpson, G.; Soldner, T.; Ur, C. A.; Urban, W.; Fraile, L. M.; Lozeva, R.; Belvito, B.; Benzoni, G.; Bruce, A.; Carroll, R.; Cieplicka-Oryǹczak, N.; Crespi, F. C. L.; Didierjean, F.; Jolie, J.; Korten, W.; Kröll, T.; Lalkovski, S.; Mach, H.; Mărginean, N.; Melon, B.; Mengoni, D.; Million, B.; Nannini, A.; Napoli, D.; Olaizola, B.; Paziy, V.; Podolyák, Zs.; Regan, P. H.; Saed-Samii, N.; Szpak, B.; Vedia, V.

    2016-09-01

    The γ-ray decay of excited states of the one-valence-proton nucleus 133Sb has been studied using cold-neutron induced fission of 235U and 241Pu targets, during the EXILL campaign at the ILL reactor in Grenoble. By using a highly efficient HPGe array, coincidences between γ-rays prompt with the fission event and those delayed up to several tens of microseconds were investigated, allowing to observe, for the first time, high-spin excited states above the 16.6 μs isomer. Lifetimes analysis, performed by fast-timing techniques with LaBr3(Ce) scintillators, revealed a difference of almost two orders of magnitude in B(M1) strength for transitions between positive-parity medium-spin yrast states. The data are interpreted by a newly developed microscopic model which takes into account couplings between core excitations (both collective and non-collective) of the doubly magic nucleus 132Sn and the valence proton, using the Skyrme effective interaction in a consistent way. The results point to a fast change in the nature of particle-core excitations with increasing spin.

  10. Differential prepuberal handling modifies behaviour and excitatory amino acids in the forebrain of the Naples High-Excitability rats.

    PubMed

    Ruocco, L A; Gironi Carnevale, U A; Sica, A; Arra, C; Topo, E; Di Giovanni, M; D'Aniello, A; Sadile, A G

    2009-03-01

    Naples High-Excitability (NHE) rats model the mesocortical variant of Attention-Deficit Hyperactivity Disorder (ADHD). Recently, a high level of excitatory amino acids (EAA) has been found in the forebrain of NHE rats. The aim of this study was to verify the effect of postnatal stimulation in prepuberal rats on forebrain EAA. Thus, prepuberal NHE and Naples Random Bred (NRB) control rats were daily handled (PS) or they were left undisturbed throughout (NO-PS). One hour after the last stimulation, PS and NO-PS rats were exposed to a spatial novelty in a Làt-maze and one day later to a non-reinforced Olton maze. In both tests the horizontal (HA) and vertical (frequency - VA and duration of rearing - RD) components of behaviour indexed activity and non-selective attention (NSA). Moreover, in the Olton maze the position of the number of arms visited before first repetition (FE) and to criterion (NVTC), indexed selective spatial attention (SSA). Amino acids were detected by HPLC in prefrontal cortex (PFC), striatum (STR), hippocampus (HPC) and hypothalamus (HYP). Results indicate that (i) in the Làt-maze, only for HA, NO-PS NHE rats were more active than PS, (ii) in the Olton maze NO-PS rats of both lines showed shorter rearing durations than PS, (iii) EAA level was higher in NHE than in NRB rats and (iv) NO-PS vs. PS treatment increased level of EAA across the forebrain in both rat lines. In contrast in NHE NO-PS rats L-glutamate (L-Glu) decreased in HYP and L-aspartate (L-Asp) decreased in HPC. In conclusion, postnatal stimulation in prepuberal rats significantly affects forebrain excitatory amino acids and behaviour in NHE line. Thus EAA are modulated by genetic determinants and environmental (epigenetic) factors.

  11. Effect of planar dielectric interfaces on fluorescence emission and detection. Evanescent excitation with high-aperture collection.

    PubMed Central

    Burghardt, T P; Thompson, N L

    1984-01-01

    We consider the effect of planar dielectric interfaces (e.g., solid/liquid) on the fluorescence emission of nearby probes. First, we derive an integral expression for the electric field radiated by an oscillating electric dipole when it is close to a dielectric interface. The electric field depends on the refractive indices of the interface, the orientation of the dipole, the distance from the dipole to the interface, and the position of observation. We numerically calculate the electric field intensity for a dipole on an interface, as a function of observation position. These results are applicable to fluorescent molecules excited by the evanescent field of a totally internally reflected laser beam and thus very close to a solid/liquid interface. Next, we derive an integral expression for the electric field radiated when a second dielectric interface is also close to the fluorescent molecule. We numerically calculate this intensity as observed through the second interface. These results are useful when the fluorescence is collected by a high-aperture microscope objective. Finally, we define and calculate a "dichroic factor," which describes the efficiency of collection, in the two-interface system, of polarized fluorescence. The limit when the first interface is removed is applicable for any high-aperture collection of polarized or unpolarized fluorescence. The limit when the second interface is removed has application in the collection of fluorescence with any aperture from molecules close to a dielectric interface. The results of this paper are required for the interpretation of order parameter measurements on fluorescent probes in supported phospholipid monolayers (Thompson, N.L., H. M. McConnell, and T. P. Burghardt, 1984, Biophys. J., 46:739-747). PMID:6518253

  12. Gabor-based kernel PCA with doubly nonlinear mapping for face recognition with a single face image.

    PubMed

    Xie, Xudong; Lam, Kin-Man

    2006-09-01

    In this paper, a novel Gabor-based kernel principal component analysis (PCA) with doubly nonlinear mapping is proposed for human face recognition. In our approach, the Gabor wavelets are used to extract facial features, then a doubly nonlinear mapping kernel PCA (DKPCA) is proposed to perform feature transformation and face recognition. The conventional kernel PCA nonlinearly maps an input image into a high-dimensional feature space in order to make the mapped features linearly separable. However, this method does not consider the structural characteristics of the face images, and it is difficult to determine which nonlinear mapping is more effective for face recognition. In this paper, a new method of nonlinear mapping, which is performed in the original feature space, is defined. The proposed nonlinear mapping not only considers the statistical property of the input features, but also adopts an eigenmask to emphasize those important facial feature points. Therefore, after this mapping, the transformed features have a higher discriminating power, and the relative importance of the features adapts to the spatial importance of the face images. This new nonlinear mapping is combined with the conventional kernel PCA to be called "doubly" nonlinear mapping kernel PCA. The proposed algorithm is evaluated based on the Yale database, the AR database, the ORL database and the YaleB database by using different face recognition methods such as PCA, Gabor wavelets plus PCA, and Gabor wavelets plus kernel PCA with fractional power polynomial models. Experiments show that consistent and promising results are obtained.

  13. Gas-Phase Reactions of Doubly Charged Lanthanide Cations with Alkanes and Alkenes. Trends in Metal(2+) Reactivity

    SciTech Connect

    Gibson, John K.; Marcalo, Joaquim; Santos, Marta; Pires de Matos, Antonio; Haire, Richard G.

    2008-12-08

    The gas-phase reactivity of doubly-charged lanthanide cations, Ln2+ (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), with alkanes (methane, ethane, propane, n-butane) and alkenes (ethene, propene, 1-butene) was studied by Fourier transform ion cyclotron resonance mass spectrometry. The reaction products consisted of different combinations of doubly-charged organometallic ions?adducts or species formed via metal-ion-induced hydrogen, dihydrogen, alkyl, or alkane eliminations from the hydrocarbons?and singly-charged ions that resulted from electron, hydride, or methide transfers from the hydrocarbons to the metal ions. The only lanthanide cations capable of activating the hydrocarbons to form doubly-charged organometallic ions were La2+, Ce2+, Gd2+, and Tb2+, which have ground-state or low-lying d1 electronic configurations. Lu2+, with an accessible d1 electronic configuration but a rather high electron affinity, reacted only through transfer channels. The remaining Ln2+ reacted via transfer channels or adduct formation. The different accessibilities of d1 electronic configurations and the range of electron affinities of the Ln2+ cations allowed for a detailed analysis of the trends for metal(2+) reactivity and the conditions for occurrence of bond activation, adduct formation, and electron, hydride, and methide transfers.

  14. Absolute concentrations of highly vibrationally excited OH(υ = 9 + 8) in the mesopause region derived from the TIMED/SABER instrument

    NASA Astrophysics Data System (ADS)

    Mast, Jeffrey; Mlynczak, Martin G.; Hunt, Linda A.; Marshall, B. Thomas; Mertens, Christoper J.; Russell, James M.; Thompson, R. Earl; Gordley, Larry L.

    2013-02-01

    Abstract Absolute concentrations (cm-3) of <span class="hlt">highly</span> vibrationally <span class="hlt">excited</span> hydroxyl (OH) are derived from measurements of the volume emission rate of the υ = 9 + 8 states of the OH radical made by the SABER instrument on the TIMED satellite. SABER has exceptionally sensitive measurement precision that corresponds to an ability to detect changes in volume emission rate on the order of ~5 <span class="hlt">excited</span> OH molecules per cm3. Peak zonal annual mean concentrations observed by SABER exceed 1000 cm-3 at night and 225 cm-3 during the day. Measurements since 2002 show an apparent altitude-dependent variation of the night OH(υ = 9 + 8) concentrations with the 11 year solar cycle, with concentrations decreasing below ~ 95 km from 2002 to 2008. These observations provide a global database for evaluating photochemical model computations of OH abundance, reaction kinetics, and rates and mechanisms responsible for maintaining vibrationally <span class="hlt">excited</span> OH in the mesopause region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18647840','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18647840"><span id="translatedtitle">UV <span class="hlt">excitation</span> of single DNA and RNA strands produces <span class="hlt">high</span> yields of exciplex states between two stacked bases.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Takaya, Tomohisa; Su, Charlene; de La Harpe, Kimberly; Crespo-Hernández, Carlos E; Kohler, Bern</p> <p>2008-07-29</p> <p><span class="hlt">Excited</span> electronic states created by UV <span class="hlt">excitation</span> of the diribonucleoside monophosphates ApA, ApG, ApC, ApU, and CpG were studied by the femtosecond transient-absorption technique. Bleach recovery signals recorded at 252 nm show that long-lived <span class="hlt">excited</span> states are formed in all five dinucleosides. The lifetimes of these states exceed those measured in equimolar mixtures of the constituent mononucleotides by one to two orders of magnitude, indicating that electronic coupling between proximal nucleobases dramatically slows the relaxation of excess electronic energy. The decay rates of the long-lived states decrease with increasing energy of the charge-transfer state produced by transferring an electron from one base to another. The charge-transfer character of the long-lived states revealed by this analysis supports their assignment to excimer or exciplex states. Identical bleach recovery signals were seen for ApA, (A)(4), and poly(A) at delay times >10 ps after photoexcitation. This indicates that <span class="hlt">excited</span> states localized on a stack of just two bases are the common trap states independent of the number of stacked nucleotides. The fraction of initial <span class="hlt">excitations</span> that decay to long-lived exciplex states is approximately equal to the fraction of stacked bases determined by NMR measurements. This supports a model in which <span class="hlt">excitations</span> associated with two stacked bases decay to exciplex states, whereas <span class="hlt">excitations</span> in unstacked bases decay via ultrafast internal conversion. These results establish the importance of charge transfer-quenching pathways for UV-irradiated RNA and DNA in room-temperature solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18647840','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18647840"><span id="translatedtitle">UV <span class="hlt">excitation</span> of single DNA and RNA strands produces <span class="hlt">high</span> yields of exciplex states between two stacked bases.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Takaya, Tomohisa; Su, Charlene; de La Harpe, Kimberly; Crespo-Hernández, Carlos E; Kohler, Bern</p> <p>2008-07-29</p> <p><span class="hlt">Excited</span> electronic states created by UV <span class="hlt">excitation</span> of the diribonucleoside monophosphates ApA, ApG, ApC, ApU, and CpG were studied by the femtosecond transient-absorption technique. Bleach recovery signals recorded at 252 nm show that long-lived <span class="hlt">excited</span> states are formed in all five dinucleosides. The lifetimes of these states exceed those measured in equimolar mixtures of the constituent mononucleotides by one to two orders of magnitude, indicating that electronic coupling between proximal nucleobases dramatically slows the relaxation of excess electronic energy. The decay rates of the long-lived states decrease with increasing energy of the charge-transfer state produced by transferring an electron from one base to another. The charge-transfer character of the long-lived states revealed by this analysis supports their assignment to excimer or exciplex states. Identical bleach recovery signals were seen for ApA, (A)(4), and poly(A) at delay times >10 ps after photoexcitation. This indicates that <span class="hlt">excited</span> states localized on a stack of just two bases are the common trap states independent of the number of stacked nucleotides. The fraction of initial <span class="hlt">excitations</span> that decay to long-lived exciplex states is approximately equal to the fraction of stacked bases determined by NMR measurements. This supports a model in which <span class="hlt">excitations</span> associated with two stacked bases decay to exciplex states, whereas <span class="hlt">excitations</span> in unstacked bases decay via ultrafast internal conversion. These results establish the importance of charge transfer-quenching pathways for UV-irradiated RNA and DNA in room-temperature solution. PMID:18647840</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvD..94f5035T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvD..94f5035T"><span id="translatedtitle"><span class="hlt">Doubly</span> assisted Sauter-Schwinger effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Torgrimsson, Greger; Oertel, Johannes; Schützhold, Ralf</p> <p>2016-09-01</p> <p>We study electron-positron pair creation by a strong and slowly varying electric field, assisted by a weaker and more rapidly changing field (e.g., in the keV regime) plus an additional <span class="hlt">high</span>-energy (say MeV) photon. It turns out that this combination can yield a pair creation probability which is exponentially larger than in the case where one (or more) of the three ingredients is missing. Apart from a deeper understanding of these nonperturbative phenomena, this double enhancement may pave the way for an experimental verification of this fundamental prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21269103','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21269103"><span id="translatedtitle">The Cascaded Arc: <span class="hlt">High</span> Flows of Rovibrationally <span class="hlt">Excited</span> H{sub 2} and its Impact on H{sup -} Ion Formation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gabriel, O.; Harskamp, W. E. N. van; Schram, D. C.; Sanden, M. C. M. van de; Engeln, R.</p> <p>2009-03-12</p> <p>The cascaded arc is a plasma source providing <span class="hlt">high</span> fluxes of <span class="hlt">excited</span> and reactive species such as ions, radicals and rovibrationally <span class="hlt">excited</span> molecules. The plasma is produced under pressures of some kPa in a direct current arc with electrical powers up to 10 kW. The plasma leaves the arc channel through a nozzle and expands with supersonic velocity into a vacuum-chamber kept by pumps at low pressures. We investigated the case of a pure hydrogen plasma jet with and without an applied axial magnetic field that confines ions and electrons in the jet. <span class="hlt">Highly</span> <span class="hlt">excited</span> molecules and atoms were detected by means of laser-induced fluorescence and optical emission spectroscopy. In case of an applied magnetic field the atomic state distribution of hydrogen atoms shows an overpopulation between the electronic states p = 5, 4 and 3. The influence of the <span class="hlt">highly</span> <span class="hlt">excited</span> hydrogen molecules on H{sup -} ion formation and a possible mechanism involving this negative ion and producing atomic hydrogen in state p = 3 will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/866980','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/866980"><span id="translatedtitle">Method and apparatus for transport, introduction, atomization and <span class="hlt">excitation</span> of emission spectrum for quantitative analysis of <span class="hlt">high</span> temperature gas sample streams containing vapor and particulates without degradation of sample stream temperature</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Eckels, David E.; Hass, William J.</p> <p>1989-05-30</p> <p>A sample transport, sample introduction, and flame <span class="hlt">excitation</span> system for spectrometric analysis of <span class="hlt">high</span> temperature gas streams which eliminates degradation of the sample stream by condensation losses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26063012','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26063012"><span id="translatedtitle">Deviation from Normal Boltzmann Distribution of <span class="hlt">High-lying</span> Energy Levels of Iron Atom <span class="hlt">Excited</span> by Okamoto-cavity Microwave-induced Plasmas Using Pure Nitrogen and Nitrogen-Oxygen Gases.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wagatsuma, Kazuaki</p> <p>2015-01-01</p> <p>This paper describes several interesting <span class="hlt">excitation</span> phenomena occurring in a microwave-induced plasma (MIP) <span class="hlt">excited</span> with Okamoto-cavity, especially when a small amount of oxygen was mixed with nitrogen matrix in the composition of the plasma gas. An ion-to-atom ratio of iron, which was estimated from the intensity ratio of ion to atomic lines having almost the same <span class="hlt">excitation</span> energy, was reduced by adding oxygen gas to the nitrogen MIP, eventually contributing to an enhancement in the emission intensities of the atomic lines. Furthermore, Boltzmann plots for iron atomic lines were observed in a wide range of the <span class="hlt">excitation</span> energy from 3.4 to 6.9 eV, indicating that plots of the atomic lines having lower <span class="hlt">excitation</span> energies (3.4 to 4.8 eV) were well fitted on a straight line while those having more than 5.5 eV deviated upwards from the linear relationship. This overpopulation would result from any other <span class="hlt">excitation</span> process in addition to the thermal <span class="hlt">excitation</span> that principally determines the Boltzmann distribution. A Penning-type collision with <span class="hlt">excited</span> species of nitrogen molecules probably explains this additional <span class="hlt">excitation</span> mechanism, in which the resulting iron ions recombine with captured electrons, followed by cascade de-<span class="hlt">excitations</span> between closely-spaced <span class="hlt">excited</span> levels just below the ionization limit. As a result, these <span class="hlt">high-lying</span> levels might be more populated than the low-lying levels of iron atom. The ionization of iron would be caused less actively in the nitrogen-oxygen plasma than in a pure nitrogen plasma, because <span class="hlt">excited</span> species of nitrogen molecule, which can provide the ionization energy in a collision with iron atom, are consumed through collisions with oxygen molecules to cause their dissociation. It was also observed that the overpopulation occurred to a lesser extent when oxygen gas was added to the nitrogen plasma. The reason for this was also attributed to decreased number density of the <span class="hlt">excited</span> nitrogen species due to collisions with oxygen</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/433393','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/433393"><span id="translatedtitle">Numerical conformal mapping methods for exterior and <span class="hlt">doubly</span> connected regions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>DeLillo, T.K.; Pfaltzgraff, J.A.</p> <p>1996-12-31</p> <p>Methods are presented and analyzed for approximating the conformal map from the exterior of the disk to the exterior a smooth, simple closed curve and from an annulus to a bounded, <span class="hlt">doubly</span> connected region with smooth boundaries. The methods are Newton-like methods for computing the boundary correspondences and conformal moduli similar to Fornberg`s method for the interior of the disk. We show that the linear systems are discretizations of the identity plus a compact operator and, hence, that the conjugate gradient method converges superlinearly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013CNSNS..18.2775Q&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013CNSNS..18.2775Q&link_type=ABSTRACT"><span id="translatedtitle">Control of synchronization and spiking regularity by heterogenous aperiodic <span class="hlt">high</span>-frequency signal in coupled <span class="hlt">excitable</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qin, Ying-Mei; Wang, Jiang; Men, Cong; Chan, Wai-Lok; Wei, Xi-Le; Deng, Bin</p> <p>2013-10-01</p> <p>This paper investigates the synchronization and spiking regularity induced by heterogenous aperiodic (HA) signal in coupled <span class="hlt">excitable</span> FitzHugh-Nagumo systems. We found new nontrivial effects of couplings and HA signals on the firing regularity and synchronization in coupled <span class="hlt">excitable</span> systems without a periodic external driving. The phenomenon is similar to array enhanced coherence resonance (AECR), and it is shown that AECR-type behavior is not limited to systems driven by noises. It implies that the HA signal may be beneficial for the brain function, which is similar to the role of noise. Furthermore, it is also found that the mean frequencies, the amplitudes and the heterogeneity of HA stimuli can serve as control parameters in modulating spiking regularity and synchronization in coupled <span class="hlt">excitable</span> systems. These results may be significant for the control of the synchronized firing of the brain in neural diseases like epilepsy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..93x5412D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..93x5412D"><span id="translatedtitle">Magnetospectroscopy of <span class="hlt">excited</span> states in charge-tunable GaAs/AlGaAs [111] quantum dots</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Durnev, M. V.; Vidal, M.; Bouet, L.; Amand, T.; Glazov, M. M.; Ivchenko, E. L.; Zhou, P.; Wang, G.; Mano, T.; Ha, N.; Kuroda, T.; Marie, X.; Sakoda, K.; Urbaszek, B.</p> <p>2016-06-01</p> <p>We present a combined experimental and theoretical study of <span class="hlt">highly</span> charged and <span class="hlt">excited</span> electron-hole complexes in strain-free (111) GaAs/AlGaAs quantum dots grown by droplet epitaxy. We address the complexes with one of the charge carriers residing in the <span class="hlt">excited</span> state, namely, the "hot" trions X-* and X+*, and the <span class="hlt">doubly</span> negatively charged exciton X2 -. Our magnetophotoluminescence experiments performed on single quantum dots in the Faraday geometry uncover characteristic emission patterns for each <span class="hlt">excited</span> electron-hole complex, which are very different from the photoluminescence spectra observed in (001)-grown quantum dots. We present a detailed theory of the fine structure and magnetophotoluminescence spectra of X-*,X+*, and X2 - complexes, governed by the interplay between the electron-hole Coulomb exchange interaction and the heavy-hole mixing, characteristic for these quantum dots with a trigonal symmetry. Comparison between experiment and theory allows for precise charge state identification, as well as extraction of electron-hole exchange interaction constants and g factors for the charge carriers occupying <span class="hlt">excited</span> states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3088378','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3088378"><span id="translatedtitle"><span class="hlt">Excited</span> Delirium</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Takeuchi, Asia; Ahern, Terence L.; Henderson, Sean O.</p> <p>2011-01-01</p> <p><span class="hlt">Excited</span> (or agitated) delirium is characterized by agitation, aggression, acute distress and sudden death, often in the pre-hospital care setting. It is typically associated with the use of drugs that alter dopamine processing, hyperthermia, and, most notably, sometimes with death of the affected person in the custody of law enforcement. Subjects typically die from cardiopulmonary arrest, although the cause is debated. Unfortunately an adequate treatment plan has yet to be established, in part due to the fact that most patients die before hospital arrival. While there is still much to be discovered about the pathophysiology and treatment, it is hoped that this extensive review will provide both police and medical personnel with the information necessary to recognize and respond appropriately to <span class="hlt">excited</span> delirium. PMID:21691475</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6901547','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6901547"><span id="translatedtitle"><span class="hlt">Excited</span> baryons</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mukhopadhyay, N.C.</p> <p>1986-01-01</p> <p>The status of the theory of the low-energy approach to hadron structure is reviewed briefly by surveying a few relevant models. A few examples of tests needed to sort out the predictions of different models pertaining to the quark-gluon structure of hadrons are discussed, and given the resulting physics objectives, a few experimental options for <span class="hlt">excited</span> baryon research at CFBAF are suggested. (LEW)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006OptL...31..930T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006OptL...31..930T"><span id="translatedtitle">Biomolecular imaging based on far-red fluorescent protein with a <span class="hlt">high</span> two-photon <span class="hlt">excitation</span> action cross section</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsai, Tsung-Han; Lin, Cheng-Yung; Tsai, Huai-Jen; Chen, Szu-Yu; Tai, Shih-Peng; Lin, Kung-Hsuan; Sun, Chi-Kuang</p> <p>2006-04-01</p> <p>The two-photon <span class="hlt">excitation</span> action cross section of Hc-Red fluorescent proteins (Hc-RFPs) is measured and found to be of the same order as that of enhanced green fluorescent proteins. With a 618 nm emission wavelength in the far-red region and with an <span class="hlt">excitation</span> wavelength around 1200 nm, Hc-RPF-based two-photon fluorescence microscopy (2PFM) can offer deep penetration capability inside live samples and is ideal for in vivo gene expression study and biomolecular imaging in live objects. In vivo 2PFM of the developing heart deep inside a transgenic zebrafish embryo tagged by Hc-RFP is also successfully demonstrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/55148','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/55148"><span id="translatedtitle">Nuclear structure effects of the nuclei {sup 152,154,156}Dy at <span class="hlt">high</span> <span class="hlt">excitation</span> energy and large angular momentum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Martin, V.; Egido, J.L.</p> <p>1995-06-01</p> <p>Using the finite-temperature Hartree-Fock-Bogoliubov formalism we analyze the properties of the nuclei {sup 152,154,156}Dy at the quasicontinuum region from {ital I}=0{h_bar} to 70{h_bar} and <span class="hlt">excitation</span> energy up to approximately 16 MeV. We discuss energy gaps, shapes, moments of inertia, and entropy among others. The role of shape fluctuations is studied in the frame of classical statistics and we find large effects on several observables. A very rich structure is found in terms of <span class="hlt">excitation</span> energy and angular momentum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22492454','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22492454"><span id="translatedtitle">Heavy rotation – evolution of quadrupole collectivity centred at the neutron-rich <span class="hlt">doubly</span> mid-shell nucleus {sup 170}Dy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Söderström, P.-A. Doornenbal, P.; Nishimura, S.; Baba, H.; Fukuda, N.; Inabe, N.; Isobe, T.; Kubo, T.; Kubono, S.; Suzuki, H.; Takeda, H.; Regan, P. H.; Walker, P. M.; Carroll, R.; Lalkovski, S.; Lotay, G.; Patel, Z.; Podolyák, Zs.; Shand, C. M.; Watanabe, H.; and others</p> <p>2015-10-15</p> <p>In this contribution the low-<span class="hlt">excitation</span> structural properties of the <span class="hlt">doubly</span> mid-shell nucleus {sup 170}Dy are discussed, with a special empasis on the evolution of the ground state rotational band within the dysprosium isotopic chain. Recent results from an experiment with the EURICA setup at RIKEN are shown in the context of previous measurements at the PRISMA+CLARA as well as the PRISMA+AGATA setups at Laboratori Nazionali di Legnaro. A brief outlook on future planned measurements is also given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhLB..751..371B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhLB..751..371B"><span id="translatedtitle">Observation of isoscalar multipole strengths in exotic <span class="hlt">doubly</span>-magic 56Ni in inelastic α scattering in inverse kinematics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bagchi, S.; Gibelin, J.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Achouri, N. L.; Akimune, H.; Bastin, B.; Boretzky, K.; Bouzomita, H.; Caamaño, M.; Càceres, L.; Damoy, S.; Delaunay, F.; Fernández-Domínguez, B.; Fujiwara, M.; Garg, U.; Grinyer, G. F.; Kamalou, O.; Khan, E.; Krasznahorkay, A.; Lhoutellier, G.; Libin, J. F.; Lukyanov, S.; Mazurek, K.; Najafi, M. A.; Pancin, J.; Penionzhkevich, Y.; Perrot, L.; Raabe, R.; Rigollet, C.; Roger, T.; Sambi, S.; Savajols, H.; Senoville, M.; Stodel, C.; Suen, L.; Thomas, J. C.; Vandebrouck, M.; Van de Walle, J.</p> <p>2015-12-01</p> <p>The Isoscalar Giant Monopole Resonance (ISGMR) and the Isoscalar Giant Dipole Resonance (ISGDR) compression modes have been studied in the <span class="hlt">doubly</span>-magic unstable nucleus 56Ni. They were measured by inelastic α-particle scattering in inverse kinematics at 50 MeV/u with the MAYA active target at the GANIL facility. The centroid of the ISGMR has been obtained at Ex = 19.1 ± 0.5 MeV. Evidence for the low-lying part of the ISGDR has been found at Ex = 17.4 ± 0.7 MeV. The strength distribution for the dipole mode shows similarity with the prediction from the Hartree-Fock (HF) based random-phase approximation (RPA) [1]. These measurements confirm inelastic α-particle scattering as a suitable probe for <span class="hlt">exciting</span> the ISGMR and the ISGDR modes in radioactive isotopes in inverse kinematics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000APS..SES.BA002B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000APS..SES.BA002B"><span id="translatedtitle">Spherical and Superdeformed Structures Near <span class="hlt">Doubly</span>-Magic Nuclei ^40Ca, ^56Ni, and ^100Sn</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baktash, Cyrus</p> <p>2000-11-01</p> <p>For more than thirty years, shell model calculations have predicted that multiparticle-multihole <span class="hlt">excitations</span> across magic numbers 8, 20 and 28 would lead to very deformed and superdeformed states in the vicinity of <span class="hlt">doubly</span>-magic nuclei ^16O, ^40Ca, and ^16Ni. These expectations were later confirmed in various cluster and mean field calculations that predicted the existence of new islands of superdeformation centered around ^32S and ^60Zn. However, it was only recently that advances in detector technology have allowed exploration of these weakly-populated structures. In this talk, I will present results of our recent experiments that have succeeded in identifying these long-sought states and their exotic decay modes. These data have provided a unique testing ground to confront, compare, and relate state-of-the-art calculations in the framework of microscopic (large-scale shell models, Quantum Monte Carlo Diagonalization), and mean field theories. Highlights of these results, including a discussion of the importance of neutron-proton pairing correlations in these nearly N=Z nuclei will be discussed. * Managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26ES...40a2066Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26ES...40a2066Z"><span id="translatedtitle">Study of a control strategy for grid side converter in <span class="hlt">doubly</span>- fed wind power system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, D. J.; Tan, Z. L.; Yuan, F.; Wang, Q. Y.; Ding, M.</p> <p>2016-08-01</p> <p>The grid side converter is an important part of the <span class="hlt">excitation</span> system of <span class="hlt">doubly</span>-fed asynchronous generator used in wind power system. As a three-phase voltage source PWM converter, it can not only transfer slip power in the form of active power, but also adjust the reactive power of the grid. This paper proposed a control approach for improving its performance. In this control approach, the dc voltage is regulated by a sliding mode variable structure control scheme and current by a variable structure controller based on the input output linearization. The theoretical bases of the sliding mode variable structure control were introduced, and the stability proof was presented. Switching function of the system has been deduced, sliding mode voltage controller model has been established, and the output of the outer voltage loop is the instruction of the inner current loop. Affine nonlinear model of two input two output equations on d-q axis for current has been established its meeting conditions of exact linearization were proved. In order to improve the anti-jamming capability of the system, a variable structure control was added in the current controller, the control law was deduced. The dual-loop control with sliding mode control in outer voltage loop and linearization variable structure control in inner current loop was proposed. Simulation results demonstrate the effectiveness of the proposed control strategy even during the dc reference voltage and system load variation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9109E..0QD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9109E..0QD"><span id="translatedtitle">Lensless coded aperture imaging with separable <span class="hlt">doubly</span> Toeplitz masks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DeWeert, Michael J.; Farm, Brian P.</p> <p>2014-05-01</p> <p>In certain imaging applications, conventional lens technology is constrained by the lack of materials which can effectively focus the radiation within reasonable weight and volume. One solution is to use coded apertures -opaque plates perforated with multiple pinhole-like openings. If the openings are arranged in an appropriate pattern, the images can be decoded, and a clear image computed. Recently, computational imaging and the search for means of producing programmable software-defined optics have revived interest in coded apertures. The former state-of-the-art masks, MURAs (Modified Uniformly Redundant Arrays) are effective for compact objects against uniform backgrounds, but have substantial drawbacks for extended scenes: 1) MURAs present an inherently ill-posed inversion problem that is unmanageable for large images, and 2) they are susceptible to diffraction: a diffracted MURA is no longer a MURA. This paper presents a new class of coded apertures, Separable <span class="hlt">Doubly</span>-Toeplitz masks, which are efficiently decodable, even for very large images -orders of magnitude faster than MURAs, and which remain decodable when diffracted. We implemented the masks using programmable spatial-lightmodulators. Imaging experiments confirmed the effectiveness of Separable <span class="hlt">Doubly</span>-Toeplitz masks - images collected in natural light of extended outdoor scenes are rendered clearly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5017283','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5017283"><span id="translatedtitle">Validation of <span class="hlt">doubly</span> labeled water method using a ruminant</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fancy, S.G.; Blanchard, J.M.; Holleman, D.F.; Kokjer, K.J.; White, R.G.</p> <p>1986-07-01</p> <p>CO/sub 2/ production (CDP, ml CO/sub 2/ . g-1 . h-1) by captive caribou and reindeer (Rangifer tarandus) was measured using the <span class="hlt">doubly</span> labeled water method (/sup 3/H/sub 2/O and H2(18)O) and compared with CO/sub 2/ expiration rates (VCO/sub 2/), adjusted for CO/sub 2/ losses in CH4 and urine, as determined by open-circuit respirometry. CDP calculated from samples of blood or urine from a reindeer in winter was 1-3% higher than the adjusted VCO/sub 2/. Differences between values derived by the two methods of 5-20% were found in summer trials with caribou. None of these differences were statistically significant (P greater than 0.05). Differences in summer could in part be explained by the net deposition of /sup 3/H, 18O, and unlabeled CO/sub 2/ in antlers and other growing tissues. Total body water volumes calculated from /sup 3/H/sub 2/O dilution were up to 15% higher than those calculated from H/sub 2/(18)O dilution. The <span class="hlt">doubly</span> labeled water method appears to be a reasonably accurate method for measuring CDP by caribou and reindeer in winter when growth rates are low, but the method may overestimate CDP by rapidly growing and/or fattening animals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10169579','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10169579"><span id="translatedtitle"><span class="hlt">Excitation</span> of <span class="hlt">high</span> frequency pressure driven modes by non-axisymmetric equilibrium at <span class="hlt">high</span> {beta}{sub pol} in PBX-M</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sesnic, S.; Kaita, R.; Kaye, S.; Okabayashi, M.; Takahashi, H.; Bell, R.E.; Bernabei, S.; Chance, M.S.; Hatcher, R.E.; Jardin, S.C.; Kessel, C.E.; Kugel, H.W.; LeBlanc, B.; Manickam, J.; Ono, M.; Paul, S.F.; Sauthoff, N.R.; Holland, A.; Asakura, N.; Duperrex, P.A.; Fonck, R.J.; Gammel, G.M.; Greene, G.J.; Jiang, T.W.; Levinton, F.M.; Powell, E.T.; Roberts, D.W.; Qin, Y.</p> <p>1993-06-01</p> <p><span class="hlt">High</span>-frequency pressure-driven modes have been observed in <span class="hlt">high</span>-poloidal-{beta} discharges in the Princeton Beta Experiment-Modification (PBX-M). These modes are <span class="hlt">excited</span> in a non-axisymmetric equilibrium characterized by a large, low frequency m{sub 1}=1/n{sub 1}=1 island, and they are capable of expelling fast ions. The modes reside on or very close to the q=1 surface, and have mode numbers with either m{sub h}=n{sub h} or (less probably) m{sub h}/n{sub h}=m{sub h}/(m{sub h}-1), with m{sub h} varying between 3 and 10. Occasionally, these modes are, simultaneously localized in the vicinity of the m{sub 1}=2/n{sub 1}=1 island. The <span class="hlt">high</span> frequency modes near the q=1 surface also exhibit a ballooning character, being significantly stronger on the large major radius side of the plasma. When a large m{sub 1}=1/n{sub 1}=1 island is present the mode is poloidally localized in the immediate vicinity of the x-point of the island. The modes, which occur exclusively in <span class="hlt">high</span>-{beta} discharges, appear to be driven by the plasma pressure or pressure gradient. They can thus be a manifestation of either a toroidicity-induced shear Alfven eigenmode (TAE) at q=(2m{sub h}+ 1)/2n{sub h}, a kinetic ballooning mode (KBM), or some other type of pressure-driven mode. Theory predicts that the TAE mode is a gap mode, but the <span class="hlt">high</span> frequency modes in PBX-M are found exclusively on or in the immediate neighborhood of magnetic surfaces with low rational numbers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11006607','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11006607"><span id="translatedtitle">Use of an automated chromium reduction system for hydrogen isotope ratio analysis of physiological fluids applied to <span class="hlt">doubly</span> labeled water analysis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schoeller, D A; Colligan, A S; Shriver, T; Avak, H; Bartok-Olson, C</p> <p>2000-09-01</p> <p>The <span class="hlt">doubly</span> labeled water method is commonly used to measure total energy expenditure in free-living subjects. The method, however, requires accurate and precise deuterium abundance determinations, which can be laborious. The aim of this study was to evaluate a fully automated, <span class="hlt">high</span>-throughput, chromium reduction technique for the measurement of deuterium abundances in physiological fluids. The chromium technique was compared with an off-line zinc bomb reduction technique and also subjected to test-retest analysis. Analysis of international water standards demonstrated that the chromium technique was accurate and had a within-day precision of <1 per thousand. Addition of organic matter to water samples demonstrated that the technique was sensitive to interference at levels between 2 and 5 g l(-1). Physiological samples could be analyzed without this interference, plasma by 10000 Da exclusion filtration, saliva by sedimentation and urine by decolorizing with carbon black. Chromium reduction of urine specimens from <span class="hlt">doubly</span> labeled water studies indicated no bias relative to zinc reduction with a mean difference in calculated energy expenditure of -0.2 +/- 3.9%. Blinded reanalysis of urine specimens from a second <span class="hlt">doubly</span> labeled water study demonstrated a test-retest coefficient of variation of 4%. The chromium reduction method was found to be a rapid, accurate and precise method for the analysis of urine specimens from <span class="hlt">doubly</span> labeled water. PMID:11006607</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11006607','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11006607"><span id="translatedtitle">Use of an automated chromium reduction system for hydrogen isotope ratio analysis of physiological fluids applied to <span class="hlt">doubly</span> labeled water analysis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schoeller, D A; Colligan, A S; Shriver, T; Avak, H; Bartok-Olson, C</p> <p>2000-09-01</p> <p>The <span class="hlt">doubly</span> labeled water method is commonly used to measure total energy expenditure in free-living subjects. The method, however, requires accurate and precise deuterium abundance determinations, which can be laborious. The aim of this study was to evaluate a fully automated, <span class="hlt">high</span>-throughput, chromium reduction technique for the measurement of deuterium abundances in physiological fluids. The chromium technique was compared with an off-line zinc bomb reduction technique and also subjected to test-retest analysis. Analysis of international water standards demonstrated that the chromium technique was accurate and had a within-day precision of <1 per thousand. Addition of organic matter to water samples demonstrated that the technique was sensitive to interference at levels between 2 and 5 g l(-1). Physiological samples could be analyzed without this interference, plasma by 10000 Da exclusion filtration, saliva by sedimentation and urine by decolorizing with carbon black. Chromium reduction of urine specimens from <span class="hlt">doubly</span> labeled water studies indicated no bias relative to zinc reduction with a mean difference in calculated energy expenditure of -0.2 +/- 3.9%. Blinded reanalysis of urine specimens from a second <span class="hlt">doubly</span> labeled water study demonstrated a test-retest coefficient of variation of 4%. The chromium reduction method was found to be a rapid, accurate and precise method for the analysis of urine specimens from <span class="hlt">doubly</span> labeled water.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V23B2813C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V23B2813C"><span id="translatedtitle">Measuring <span class="hlt">doubly</span> 13C-substituted ethane by mass spectrometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clog, M.; Ling, C.; Eiler, J. M.</p> <p>2012-12-01</p> <p>Ethane (C2H6) is present in non-negligible amounts in most natural gas reservoirs and is used to produce ethylene for petrochemical industries. It is one of the by-products of lipid metabolism and is the arguably simplest molecule that can manifest multiple 13C substitutions. There are several plausible controls on the relative abundances of 13C2H6 in natural gases: thermodynamically controlled homogeneous isotope exchange reactions analogous to those behind carbonate clumped isotope thermometry; inheritance from larger biomolecules that under thermal degradation to produce natural gas; mixing of natural gases that differ markedly in bulk isotopic composition; or combinations of these and/or other, less expected fractionations. There is little basis for predicting which of these will dominate in natural samples. Here, we focus on an analytical techniques that will provide the avenue for exploring these phenomena. The method is based on <span class="hlt">high</span>-resolution gas source isotope ratio mass spectrometry, using the Thermo 253-Ultra (a new prototype mass spectrometer). This instrument achieves the mass resolution (M/Δ M) up to 27,000, permitting separation of the isobaric interferences of potential contaminants and isotopologues of an analtye or its fragments which share a cardinal mass. We present techniques to analyze several isotopologues of molecular and fragment ions of C2H6. The critical isobaric separations for our purposes include: discrimination of 13C2H6 from 13C12CDH5 at mass 32 and separation of the 13CH3 fragment from 12CH4 at mass 16, both requiring at least a mass resolution of 20000 to make an adequate measurement. Other obvious interferences are either cleanly separated (e.g., O2, O) or accounted for by peak-stripping (CH3OH on mass 32 and NH2 on mass 16). We focus on a set of measurements which constrain: the <span class="hlt">doubly</span>-substituted isotopologue, 13C2H6, and the 13CH3/12CH3 ratio of the methyl fragment, which constrains the bulk δ 13C. Similar methods can be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013NucFu..53g3040I&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013NucFu..53g3040I&link_type=ABSTRACT"><span id="translatedtitle">Coupling of ICRF waves and axial transport of <span class="hlt">high</span>-energy ions owing to spontaneously <span class="hlt">excited</span> waves in the GAMMA 10 tandem mirror</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ikezoe, R.; Ichimura, M.; Hirata, M.; Iwai, T.; Yokoyama, T.; Ugajin, Y.; Sato, T.; Iimura, T.; Saito, Y.; Yoshikawa, M.; Kohagura, J.; Shima, Y.; Imai, T.</p> <p>2013-07-01</p> <p>Plasmas with <span class="hlt">high</span> ion temperature of several kiloelectronvolts and a strong temperature anisotropy of greater than 10 were produced by ion cyclotron range of frequency (ICRF) heating in the GAMMA 10 tandem mirror. In such <span class="hlt">high</span>-performance plasmas with strong anisotropy, <span class="hlt">high</span>-frequency fluctuations, so-called Alfvén-ion-cyclotron (AIC) waves, are <span class="hlt">excited</span> spontaneously. These AIC waves have several discrete peaks in the frequency spectrum. Coupling of the ICRF heating waves and the <span class="hlt">excited</span> AIC waves was clearly observed in the density fluctuations measured with a newly developed reflectometer. Parametric decay from the heating ICRF waves to the AIC waves and low-frequency waves was also indicated. Alfvén waves with difference frequencies between the discrete peaks of the AIC waves were detected in a signal that measured the number of axially transported <span class="hlt">high</span>-energy ions (over 6 keV) at the machine end, indicating pitch-angle scattering caused by the low-frequency waves. Energy transport along the magnetic field line is an important consideration when ICRF power is injected in the perpendicular direction to a magnetic field line. The importance of the spontaneously <span class="hlt">excited</span> AIC waves for axial confinement of a tandem mirror through wave-wave couplings was demonstrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20439130','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20439130"><span id="translatedtitle"><span class="hlt">Excited</span> protein states of human tear lipocalin for low- and <span class="hlt">high</span>-affinity ligand binding revealed by functional AB loop motion.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gasymov, Oktay K; Abduragimov, Adil R; Glasgow, Ben J</p> <p>2010-06-01</p> <p>Human tear lipocalin (TL), a prominent member of lipocalin family, exhibits functional and structural promiscuity. The plasticity of loop regions modulates entry to the ligand pocket at the "open" end of the eight-stranded beta-barrel. Site-directed multi-distance measurements using fluorescence resonance energy transfer between functional loops register two <span class="hlt">excited</span> protein states for low- and <span class="hlt">high</span>-affinity ligand binding. At low pH, the longest loop AB adopts the conformation of the low-affinity <span class="hlt">excited</span> protein state that matches the crystal structure of holo-TL at pH 8. A "crankshaft" like movement is detected for the loop AB in a low pH transition. At pH 7.3 the holo-protein assumes a <span class="hlt">high</span>-affinity <span class="hlt">excited</span> protein state, in which the loop AB is more compact (RMS=3.1A). In the apo-holo transition, the reporter Trp 28 moves about 4.5A that reflects a decrease in distance between Glu27 and Lys108. This interaction fixes the loop AB conformation for the <span class="hlt">high</span>-affinity mode. No such movement is detected at low pH, where Glu27 is protonated. Data strongly indicate that the protonation state of Glu27 modulates the conformation of the loop AB for <span class="hlt">high</span>- and low-affinity binding. PMID:20439130</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/949223','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/949223"><span id="translatedtitle">Sexual <span class="hlt">excitement</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stoller, R J</p> <p>1976-08-01</p> <p>Sexual <span class="hlt">excitement</span> depends on a scenario the person to be aroused has been writing since childhood. The story is an adventure, an autobiography disguised as fiction, in which the hero/heroine hides crucial intrapsychic conflicts, mysteries, screen memories of actual traumatic events and the resolution of these elements into a happy ending, best celebrated by orgasm. The function of the fantasy is to take these painful experiences and convert them to pleasure-triumph. In order to sharpen <span class="hlt">excitement</span>-the vibration between the fear of original traumas repeating and the hope of a pleasurable conclusion this time-one introduces into the story elements of risk (approximations of the trauma) meant to prevent boredom and safety factors (sub-limnal signals to the storyteller that the risk are not truly dangerous). Sexual fantasy can be studied by means of a person's daydreams (including those chosen in magazines, books, plays, television, movies, and outright pornography), masturbatory behavior, object choice, foreplay, techniques of intercourse, or postcoital behavior. PMID:949223</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/949223','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/949223"><span id="translatedtitle">Sexual <span class="hlt">excitement</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stoller, R J</p> <p>1976-08-01</p> <p>Sexual <span class="hlt">excitement</span> depends on a scenario the person to be aroused has been writing since childhood. The story is an adventure, an autobiography disguised as fiction, in which the hero/heroine hides crucial intrapsychic conflicts, mysteries, screen memories of actual traumatic events and the resolution of these elements into a happy ending, best celebrated by orgasm. The function of the fantasy is to take these painful experiences and convert them to pleasure-triumph. In order to sharpen <span class="hlt">excitement</span>-the vibration between the fear of original traumas repeating and the hope of a pleasurable conclusion this time-one introduces into the story elements of risk (approximations of the trauma) meant to prevent boredom and safety factors (sub-limnal signals to the storyteller that the risk are not truly dangerous). Sexual fantasy can be studied by means of a person's daydreams (including those chosen in magazines, books, plays, television, movies, and outright pornography), masturbatory behavior, object choice, foreplay, techniques of intercourse, or postcoital behavior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995ApOpt..34.3257B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995ApOpt..34.3257B"><span id="translatedtitle">Pulsed-laser <span class="hlt">excitation</span> of acoustic modes in open <span class="hlt">high</span>-Q photoacoustic resonators for trace gas monitoring: results for C2H4</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brand, Christian; Winkler, Andreas; Hess, Peter; Miklós, András; Bozóki, Zoltán; Sneider, János</p> <p>1995-06-01</p> <p>The pulsed <span class="hlt">excitation</span> of acoustic resonances was studied with a continuously monitoring photoacoustic detector system. Acoustic waves were generated in C2H4/N 2 gas mixtures by light absorption of the pulses from a transversely <span class="hlt">excited</span> atmospheric CO2 laser. The photoacoustic part consisted of <span class="hlt">high</span>-Q cylindrical resonators (Q factor 820 for the first radial mode in N2) and two adjoining variable acoustic filter systems. The time-resolved signal was Fourier transformed to a frequency spectrum of <span class="hlt">high</span> resolution. For the first radial mode a Lorentzian profile was fitted to the measured data. The outside noise suppression and the signal-to-noise ratio were investigated in a normal laboratory environment in the flow-through mode. The acoustic and electric filter system combined with the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26186832','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26186832"><span id="translatedtitle">The effect of <span class="hlt">high</span> viscosity on the collapse-like chaotic and regular periodic oscillations of a harmonically <span class="hlt">excited</span> gas bubble.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hegedűs, Ferenc; Klapcsik, Kálmán</p> <p>2015-11-01</p> <p>In the last decade many industrial applications have emerged based on the rapidly developing ultrasonic technology such as ultrasonic pasteurization, alteration of the viscosity of food systems, and mixing immiscible liquids. The fundamental physical basis of these applications is the prevailing extreme conditions (<span class="hlt">high</span> temperature, pressure and even shock waves) during the collapse of acoustically <span class="hlt">excited</span> bubbles. By applying the sophisticated numerical techniques of modern bifurcation theory, the present study intends to reveal the regions in the <span class="hlt">excitation</span> pressure amplitude-ambient temperature parameter plane where collapse-like motion of an acoustically driven gas bubble in <span class="hlt">highly</span> viscous glycerine exists. We report evidence that below a threshold temperature the bubble model, the Keller-Miksis equation, becomes an overdamped oscillator suppressing collapse-like behaviour. In addition, we have found periodic windows interspersed with chaotic regions indicating the presence of transient chaos, which is important from application point of view if predictability is required. PMID:26186832</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1182522','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1182522"><span id="translatedtitle">Evidence for a new <span class="hlt">excitation</span> at the interface between a <span class="hlt">high</span>-<math><msub><mi>T</mi><mi>c</mi></msub></math> superconductor and a topological insulator</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zareapour, Parisa; Hayat, Alex; Zhao, Shu Yang F.; Kreshchuk, Michael; Lee, Yong Kiat; Reijnders, Anjan A.; Jain, Achint; Xu, Zhijun; Liu, T. S.; Gu, G. D.; Jia, Shuang; Cava, Robert J.; Burch, Kenneth S.</p> <p>2014-12-09</p> <p>In this research, <span class="hlt">high</span>-temperature superconductors exhibit a wide variety of novel <span class="hlt">excitations</span>. If contacted with a topological insulator, the lifting of spin rotation symmetry in the surface states can lead to the emergence of unconventional superconductivity and novel particles. In pursuit of this possibility, we fabricated <span class="hlt">high</span> critical-temperature (T<sub>c</sub> ~ 85 K) superconductor/topological insulator (Bi₂Sr₂CaCu₂O₈₊<sub>δ</sub>/Bi₂Te₂Se) junctions. Below 75 K, a zero-bias conductance peak (ZBCP) emerges in the differential conductance spectra of this junction. The magnitude of the ZBCP is suppressed at the same rate for magnetic fields applied parallel or perpendicular to the junction. Furthermore, it can still be observed and does not split up to at least 8.5 T. The temperature and magnetic field dependence of the <span class="hlt">excitation</span> we observe appears to fall outside the known paradigms for a ZBCP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26186832','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26186832"><span id="translatedtitle">The effect of <span class="hlt">high</span> viscosity on the collapse-like chaotic and regular periodic oscillations of a harmonically <span class="hlt">excited</span> gas bubble.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hegedűs, Ferenc; Klapcsik, Kálmán</p> <p>2015-11-01</p> <p>In the last decade many industrial applications have emerged based on the rapidly developing ultrasonic technology such as ultrasonic pasteurization, alteration of the viscosity of food systems, and mixing immiscible liquids. The fundamental physical basis of these applications is the prevailing extreme conditions (<span class="hlt">high</span> temperature, pressure and even shock waves) during the collapse of acoustically <span class="hlt">excited</span> bubbles. By applying the sophisticated numerical techniques of modern bifurcation theory, the present study intends to reveal the regions in the <span class="hlt">excitation</span> pressure amplitude-ambient temperature parameter plane where collapse-like motion of an acoustically driven gas bubble in <span class="hlt">highly</span> viscous glycerine exists. We report evidence that below a threshold temperature the bubble model, the Keller-Miksis equation, becomes an overdamped oscillator suppressing collapse-like behaviour. In addition, we have found periodic windows interspersed with chaotic regions indicating the presence of transient chaos, which is important from application point of view if predictability is required.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011mss..confETG08M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011mss..confETG08M"><span id="translatedtitle"><span class="hlt">Excited</span> State Dynamics of 7-AZAINDOLE Homodimer in Frozen Nitrogen Matrix</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mukherjee, Moitrayee; Bandyopadhyay, Biman; Karmakar, Shreetama; Chakraborty, Tapas</p> <p>2011-06-01</p> <p>In a fluid medium (liquid or gas), the <span class="hlt">doubly</span> hydrogen bonded dimer of 7-azaindole (7AI) undergoes tautomerization via simultaneous exchange of two H-atoms/protons between the two moieties upon UV <span class="hlt">excitation</span> to lowest <span class="hlt">excited</span> singlet state. The <span class="hlt">excited</span> dimer emits exclusively visible fluorescence from tautomeric configuration, and no UV fluorescence is detected from the locally <span class="hlt">excited</span> state. We show here for the first time that this generic <span class="hlt">excited</span> state dynamics of 7AI dimer is totally altered if the species is synthesized and confined in frozen nitrogen at 8 K. The dimer has been found to emit only from the locally <span class="hlt">excited</span> state, and the photophysical channel leading to <span class="hlt">excited</span> state tautomerization is completely blocked. The formation of the centrosymmetric dimer in nitrogen matrix is ensured by recording the FTIR spectrum of the dimer before initiating the photophysical measurements. The details of our findings and interpretation of the measured data will be presented in the talk.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21467035','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21467035"><span id="translatedtitle">Discovery of <span class="hlt">Highly</span> <span class="hlt">Excited</span> Long-Lived Isomers in Neutron-Rich Hafnium and Tantalum Isotopes through Direct Mass Measurements</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Reed, M. W.; Cullen, I. J.; Walker, P. M.; Deo, A. Y.; Kempley, R. S.; Swan, T. P. D.; Litvinov, Yu. A.; Winckler, N.; Blaum, K.; Bosch, F.; Dimopoulou, C.; Farinon, F.; Heil, M.; Knoebel, R.; Kozhuharov, C.; Kurcewicz, J.; Kuzminchuk, N.; Litvinov, S.; Nociforo, C.; Nolden, F.</p> <p>2010-10-22</p> <p>A study of cooled {sup 197}Au projectile-fragmentation products has been performed with a storage ring. This has enabled metastable nuclear <span class="hlt">excitations</span> with energies up to 3 MeV, and half-lives extending to minutes or longer, to be identified in the neutron-rich nuclides {sup 183,184,186}Hf and {sup 186,187}Ta. The results support the prediction of a strongly favored isomer region near neutron number 116.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2791225','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2791225"><span id="translatedtitle">Opposite Effects of Low and <span class="hlt">High</span> Doses of Aβ42 on Electrical Network and Neuronal <span class="hlt">Excitability</span> in the Rat Prefrontal Cortex</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Yun; Zhang, Guangping; Zhou, Hongwei; Barakat, Amey; Querfurth, Henry</p> <p>2009-01-01</p> <p>Changes in neuronal synchronization have been found in patients and animal models of Alzheimer's disease (AD). Synchronized behaviors within neuronal networks are important to such complex cognitive processes as working memory. The mechanisms behind these changes are not understood but may involve the action of soluble β-amyloid (Aβ) on electrical networks. In order to determine if Aβ can induce changes in neuronal synchronization, the activities of pyramidal neurons were recorded in rat prefrontal cortical (PFC) slices under calcium-free conditions using multi-neuron patch clamp technique. Electrical network activities and synchronization among neurons were significantly inhibited by low dose Aβ42 (1 nM) and initially by <span class="hlt">high</span> dose Aβ42 (500 nM). However, prolonged application of <span class="hlt">high</span> dose Aβ42 resulted in network activation and tonic firing. Underlying these observations, we discovered that prolonged application of low and <span class="hlt">high</span> doses of Aβ42 induced opposite changes in action potential (AP)-threshold and after-hyperpolarization (AHP) of neurons. Accordingly, low dose Aβ42 significantly increased the AP-threshold and deepened the AHP, making neurons less <span class="hlt">excitable</span>. In contrast, <span class="hlt">high</span> dose Aβ42 significantly reduced the AP-threshold and shallowed the AHP, making neurons more <span class="hlt">excitable</span>. These results support a model that low dose Aβ42 released into the interstitium has a physiologic feedback role to dampen electrical network activity by reducing neuronal <span class="hlt">excitability</span>. Higher concentrations of Aβ42 over time promote supra-synchronization between individual neurons by increasing their <span class="hlt">excitability</span>. The latter may disrupt frontal-based cognitive processing and in some cases lead to epileptiform discharges. PMID:20027222</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1185935-high-energy-magnetic-excitations-overdoped-la2-xsrxcuo4-studied-neutron-resonant-inelastic-ray-scattering','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1185935-high-energy-magnetic-excitations-overdoped-la2-xsrxcuo4-studied-neutron-resonant-inelastic-ray-scattering"><span id="translatedtitle"><span class="hlt">High</span>-energy magnetic <span class="hlt">excitations</span> in overdoped La2-xSrxCuO4 studied by neutron and resonant inelastic X-ray scattering</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Wakimoto, S.; Ishii, K.; Kimura, H.; Fujita, M.; Dellea, G.; Kummer, K.; Braicovich, L.; Ghiringhelli, G.; Debeer-Schmitt, Lisa M.; Granroth, Garrett E.</p> <p>2015-05-21</p> <p>We have performed neutron inelastic scattering and resonant inelastic x-ray scattering (RIXS) at the Cu-L3 edge to study <span class="hlt">high</span>-energy magnetic <span class="hlt">excitations</span> at energy transfers of more than 100 meV for overdoped La2₋xSrxCuO4 with x=0.25 (Tc=15 K) and x=0.30 (nonsuperconducting) using identical single-crystal samples for the two techniques. From constant-energy slices of neutron-scattering cross sections, we have identified magnetic <span class="hlt">excitations</span> up to ~250 meV for x=0.25. Although the width in the momentum direction is large, the peak positions along the (π,π) direction agree with the dispersion relation of the spin wave in the nondoped La2CuO4 (LCO), which is consistent with themore » previous RIXS results of cuprate superconductors. Using RIXS at the Cu-L3 edge, we have measured the dispersion relations of the so-called paramagnon mode along both (π,π) and (π,0) directions. Although in both directions the neutron and RIXS data connect with each other and the paramagnon along (π,0) agrees well with the LCO spin-wave dispersion, the paramagnon in the (π,π) direction probed by RIXS appears to be less dispersive and the <span class="hlt">excitation</span> energy is lower than the spin wave of LCO near (π/2,π/2). Thus, our results indicate consistency between neutron inelastic scattering and RIXS, and elucidate the entire magnetic <span class="hlt">excitation</span> in the (π,π) direction by the complementary use of two probes. The polarization dependence of the RIXS profiles indicates that appreciable charge <span class="hlt">excitations</span> exist in the same energy range of magnetic <span class="hlt">excitations</span>, reflecting the itinerant character of the overdoped sample. Lastly, we find a possible anisotropy in the charge <span class="hlt">excitation</span> intensity might explain the apparent differences in the paramagnon dispersion in the (π,π) direction as detected by the x-ray scattering.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2255756D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2255756D"><span id="translatedtitle">On the Complexity of H2 <span class="hlt">Excitation</span> Near Hot Stars: <span class="hlt">High</span> Spectral and Spatial Resolution Observations of Compact Planetary Nebulae with IGRINS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dinerstein, Harriet L.; Kaplan, Kyle F.; Jaffe, Daniel T.</p> <p>2015-08-01</p> <p>Near-infrared emission lines of vibrationally-<span class="hlt">excited</span> H2 were first detected in planetary nebulae (PNe) four decades ago. In some environments, e.g. outflows from low-mass young stellar objects, such emission is generally attributed to shock heating. The situation is more complicated for PNe, which host more than one potential agent of <span class="hlt">excitation</span>. Shocks are indeed present within PNe, due to interactions among expanding layers of different velocities. On the other hand, the UV radiation field of the central star can populate <span class="hlt">excited</span> vibrational levels of the ground electronic state via an indirect process, initiated by transitions to <span class="hlt">excited</span> electronic states upon absorption of non-H-ionizing UV photons (the H2 Lyman-Werner bands), followed by radiative decay. When not modified by other processes, this produces a <span class="hlt">highly</span> distinctive “pure fluorescent” H2 spectrum (Black & van Dishoeck 1987, ApJ, 322, 412). Such emission was first identified in a PN, Hb 12, by Dinerstein et al. 1988 (ApJ, 327, L27). Later surveys (e.g. Hora et al. 1999, ApJS, 124, 195; Likkel & Dinerstein et al. 2006, AJ, 131, 1515) found that some PNe display thermal (collisionally-dominated) spectra, a few are fluorescent, and others show intermediate line ratios. It is not always easy to distinguish whether the latter is due to a superposition of radiative and shock components (Davis et al. 2003, MNRAS, 344, 262), or to thermalization of initially radiatively <span class="hlt">excited</span> molecules due to <span class="hlt">high</span> density, a hard radiation field, and/or advective effects (e.g. Henney et al. 2007, ApJ, 671, 137). We present new observations of H2 in PNe obtained with the <span class="hlt">high</span>-spectral resolution (R = 40,000), broad spectral grasp IGRINS spectrometer (Park & Jaffe et al. 2014, Proc SPIE, 9147). This instrument reveals small-scale structures in position-velocity space that differ in <span class="hlt">excitation</span> and emergent line ratios. For example, the compact PN M 1-11 contains both a fluorescent shell of H2 and higher-velocity compact </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AAS...22020804F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AAS...22020804F"><span id="translatedtitle">Radiative Rates for Forbidden Transitions in <span class="hlt">Doubly</span>-Ionized Fe-Peak Elements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fivet, Vanessa; Quinet, P.; Bautista, M.</p> <p>2012-05-01</p> <p>Accurate and reliable atomic data for lowly-ionized Fe-peak species (Sc, Ti, V, Cr, Mn, Fe, Co, Ni and Cu) are of paramount importance for the analysis of the <span class="hlt">high</span> resolution astrophysical spectra currently available. The third spectra of several iron group elements have been observed in different galactic sources like Herbig-Haro objects in the Orion Nebula [1] and stars like Eta Carinae [2]. However, forbidden transitions between low-lying metastable levels of <span class="hlt">doubly</span>-ionized iron-peak ions have been very little investigated so far and radiative rates for those lines remain sparse or inexistent. We are carrying out a systematic study of the electronic structure of <span class="hlt">doubly</span>-ionized iron-peak elements. The magnetic dipole (M1) and electric quadrupole (E2) transition probabilities are computed using the pseudo-relativistic Hartree-Fock (HFR) code of Cowan [3] and the central Thomas-Fermi-Dirac potential approximation implemented in AUTOSTRUCTURE [4]. This multi-platform approach allows for consistency checks and intercomparison and has proven very successful in the study of the complex Fe-peak species where many different effects contribute [5]. References [1] A. Mesa-Delgado et al., MNRAS 395 (2009) 855 [2] S. Johansson et al., A&A 361 (2000) 977 [3] R.D. Cowan, The Theory of Atomic Structure and Spectra, Berkeley: Univ. California Press (1981) [4] N.R. Badnell, J. Phys. B: At. Mol. Opt. Phys. 30 (1997) 1 [5] M. Bautista et al., ApJ 718 (2010) L189</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhD...49w5501L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhD...49w5501L"><span id="translatedtitle">Spoof surface plasmon modes on <span class="hlt">doubly</span> corrugated metal surfaces at terahertz frequencies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Yong-Qiang; Kong, Ling-Bao; Du, Chao-Hai; Liu, Pu-Kun</p> <p>2016-06-01</p> <p>Spoof surface plasmons (SSPs) have many potential applications such as imaging and sensing, communications, innovative leaky wave antenna and many other passive devices in the microwave and terahertz (THz) spectrum. The extraordinary properties of SSPs (e.g. extremely strong near field, enhanced beam–wave interaction) make them especially attractive for developing novel THz electronic sources. SSP modes on <span class="hlt">doubly</span> corrugated metal surfaces are investigated and analyzed both theoretically and numerically in this paper. The analytical SSP dispersion expressions of symmetric and anti-symmetric modes are obtained with a simplified modal field expansion method; the results are also verified by the finite integration method. Additionally, the propagation losses are also considered for real copper surfaces with a limited constant conductivity in a THz regime. It is shown that the asymptotical frequency of the symmetric mode at the Brillouin boundary decreases along with the decreased gap size between these two corrugated metal surfaces while the asymptotical frequency increases for the anti-symmetric mode. The anti-symmetric mode demonstrates larger propagation losses than the symmetric mode. Further, the losses for both symmetric and anti-symmetric modes decrease when this gap size enlarges. By decreasing groove depth, the asymptotical frequency increases for both the symmetric and the anti-symmetric mode, but the variation of propagation losses is more complicated. Propagation losses increase along with the increased period. Our studies on the dispersion characteristics and propagation losses of SSP modes on this <span class="hlt">doubly</span> corrugated metallic structure with various parameters is instructive for numerous applications such as waveguides, circuitry systems with <span class="hlt">high</span> integration, filters and powerful electronic sources in the THz regime.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AIPC..811..156O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AIPC..811..156O"><span id="translatedtitle">(γ, 2γ) studies on multiply <span class="hlt">excited</span> states of H2 and N2 in the vacuum ultraviolet range</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Odagiri, Takeshi</p> <p>2006-01-01</p> <p>The <span class="hlt">doubly</span> differential cross sections for the emission of two photons from <span class="hlt">excited</span> fragments in photoexcitation of molecules have been measured as a function of incident photon energy by using a new method, (γ, 2γ) method. The cross section curves that are free from ionization have been obtained for the first time. It has been shown that the (γ, 2γ) method is a powerful tool for investigating the spectroscopy and dynamics of the multiply <span class="hlt">excited</span> molecules.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19113541','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19113541"><span id="translatedtitle">Observation of the <span class="hlt">doubly</span> strange b baryon Omegab-.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abazov, V M; Abbott, B; Abolins, M; Acharya, B S; Adams, M; Adams, T; Aguilo, E; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Ancu, L S; Andeen, T; Andrieu, B; Anzelc, M S; Aoki, M; Arnoud, Y; Arov, M; Arthaud, M; Askew, A; Asman, B; Assis Jesus, A C S; Atramentov, O; Avila, C; Badaud, F; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, P; Banerjee, S; Barberis, E; Barfuss, A-F; Bargassa, P; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Bellavance, A; Benitez, J A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Biscarat, C; Blazey, G; Blekman, F; Blessing, S; Bloom, K; Boehnlein, A; Boline, D; Bolton, T A; Boos, E E; Borissov, G; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Bu, X B; Buchanan, N J; Buchholz, D; Buehler, M; Buescher, V; Bunichev, V; Burdin, S; Burnett, T H; Buszello, C P; Butler, J M; Calfayan, P; Calvet, S; Cammin, J; Carrera, E; Carvalho, W; Casey, B C K; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chandra, A; Cheu, E; Chevallier, F; Cho, D K; Choi, S; Choudhary, B; Christofek, L; Christoudias, T; Cihangir, S; Claes, D; Clutter, J; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Crépé-Renaudin, S; Cuplov, V; Cutts, D; Cwiok, M; da Motta, H; Das, A; Davies, G; De, K; de Jong, S J; De La Cruz-Burelo, E; De Oliveira Martins, C; DeVaughan, K; Degenhardt, J D; Déliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Dominguez, A; Dong, H; Dorland, T; Dubey, A; Dudko, L V; Duflot, L; Dugad, S R; Duggan, D; Duperrin, A; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Ermolov, P; Evans, H; Evdokimov, A; Evdokimov, V N; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Garcia, C; Garcia-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Geng, W; Gerber, C E; Gershtein, Y; Gillberg, D; Ginther, G; Gollub, N; Gómez, B; Goussiou, A; Grannis, P D; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, F; Guo, J; Gutierrez, G; Gutierrez, P; Haas, A; Hadley, N J; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Harder, K; Harel, A; Hauptman, J M; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinson, A P; Heintz, U; Hensel, C; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hoeth, H; Hohlfeld, M; Hossain, S; Houben, P; Hu, Y; Hubacek, Z; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jarvis, C; Jesik, R; Johns, K; Johnson, C; Johnson, M; Johnston, D; Jonckheere, A; Jonsson, P; Juste, A; Kajfasz, E; Kalk, J M; Karmanov, D; Kasper, P A; Katsanos, I; Kau, D; Kaushik, V; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y M; Khatidze, D; Kim, T J; Kirby, M H; Kirsch, M; Klima, B; Kohli, J M; Komissarov, E V; Konrath, J-P; Kozelov, A V; Kraus, J; Kuhl, T; Kumar, A; Kupco, A; Kurca, T; Kuzmin, V A; Kvita, J; Lacroix, F; Lam, D; Lammers, S; Landsberg, G; Lebrun, P; Lee, W M; Leflat, A; Lellouch, J; Li, J; Li, L; Li, Q Z; Lietti, S M; Lim, J K; Lima, J G R; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobodenko, A; Lokajicek, M; Love, P; Lubatti, H J; Luna, R; Lyon, A L; Maciel, A K A; Mackin, D; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Maravin, Y; Martin, B; McCarthy, R; Melnitchouk, A; Mendoza, L; Mercadante, P G; Merekov, Y P; Merkin, M; Merritt, K W; Meyer, A; Meyer, J; Mitrevski, J; Mommsen, R K; Mondal, N K; Moore, R W; Moulik, T; Muanza, G S; Mulhearn, M; Mundal, O; Mundim, L; Nagy, E; Naimuddin, M; Narain, M; Naumann, N A; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Nogima, H; Novaes, S F; Nunnemann, T; O'Dell, V; O'Neil, D C; Obrant, G; Ochando, C; Onoprienko, D; Orduna, J; Oshima, N; Osman, N; Osta, J; Otec, R; Otero y Garzón, G J; Owen, M; Padley, P; Pangilinan, M; Parashar, N; Park, S-J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Penning, B; Perfilov, M; Peters, K; Peters, Y; Pétroff, P; Petteni, M; Piegaia, R; Piper, J; Pleier, M-A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M-E; Polozov, P; Pope, B G; Popov, A V; Potter, C; Prado da Silva, W L; Prosper, H B; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rakitine, A; Rangel, M S; Ranjan, K; Ratoff, P N; Renkel, P; Rich, P; Rieger, J; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Robinson, S; Rodrigues, R F; Rominsky, M; Royon, C; Rozhdestvenski, A; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Sanghi, B; Savage, G; Sawyer, L; Scanlon, T; Schaile, D; Schamberger, R D; Scheglov, Y; Schellman, H; Schliephake, T; Schlobohm, S; Schwanenberger, C; Schwartzman, A; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shivpuri, R K; Siccardi, V; Simak, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Spurlock, B; Stark, J; Steele, J; Stolin, V; Stoyanova, D A; Strandberg, J; Strandberg, S; Strang, M A; Strauss, E; Strauss, M; Ströhmer, R; Strom, D; Stutte, L; Sumowidagdo, S; Svoisky, P; Sznajder, A; Tamburello, P; Tanasijczuk, A; Taylor, W; Tiller, B; Tissandier, F; Titov, M; Tokmenin, V V; Torchiani, I; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Unalan, R; Uvarov, L; Uvarov, S; Uzunyan, S; Vachon, B; van den Berg, P J; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Verdier, P; Vertogradov, L S; Vertogradova, Y; Verzocchi, M; Vilanova, D; Villeneuve-Seguier, F; Vint, P; Vokac, P; Voutilainen, M; Wagner, R; Wahl, H D; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weber, G; Weber, M; Welty-Rieger, L; Wenger, A; Wermes, N; Wetstein, M; White, A; Wicke, D; Williams, M; Wilson, G W; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Yacoob, S; Yamada, R; Yang, W-C; Yasuda, T; Yatsunenko, Y A; Yin, H; Yip, K; Yoo, H D; Youn, S W; Yu, J; Zeitnitz, C; Zelitch, S; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zieminski, A; Zivkovic, L; Zutshi, V; Zverev, E G</p> <p>2008-12-01</p> <p>We report the observation of the <span class="hlt">doubly</span> strange b baryon Omegab- in the decay channel Omegab(-)-->J/psiOmega-, with J/psi-->mu+mu(-) and Omega(-)-->LambdaK(-)-->(ppi-)K-, in pp collisions at sqrt[s]=1.96 TeV. Using approximately 1.3 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron Collider, we observe 17.8+/-4.9(stat)+/-0.8(syst) Omegab- signal events at a mass of 6.165+/-0.010(stat)+/-0.013(syst) GeV. The significance of the observed signal is 5.4sigma, corresponding to a probability of 6.7 x 10(-8) of it arising from a background fluctuation. PMID:19113541</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ChPhB..25a3401S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ChPhB..25a3401S"><span id="translatedtitle">Triple differential cross sections of magnesium in <span class="hlt">doubly</span> symmetric geometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>S, Y. Sun; X, Y. Miao; Xiang-Fu, Jia</p> <p>2016-01-01</p> <p>A dynamically screened three-Coulomb-wave (DS3C) method is applied to study the single ionization of magnesium by electron impact. Triple differential cross sections (TDCS) are calculated in <span class="hlt">doubly</span> symmetric geometry at incident energies of 13.65, 17.65, 22.65, 27.65, 37.65, 47.65, 57.65, and 67.65 eV. Comparisons are made with experimental data and theoretical predictions from a three-Coulomb-wave function (3C) approach and distorted-wave Born approximation (DWBA). The overall agreement between the predictions of the DS3C model and the DWBA approach with the experimental data is satisfactory. Project supported by the National Natural Science Foundation of China (Grant No. 11274215).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/563341','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/563341"><span id="translatedtitle">Respiratory compensation in cardiac PET using <span class="hlt">doubly</span>-gated acquisitions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Huesman, R.H.; Klein, G.J.; Reutter, B.W.</p> <p>1997-05-01</p> <p>We present results of respiratory compensation in cardiac PET data via <span class="hlt">doubly</span>-gated acquisitions on a human subject. The extent of cardiac motion due to respiration has now been documented by numerous researchers. To correct for the blurring effects of this motion, we have modified the CTI/Siemens ECAT EXACT HR scanner to support acquisitions gated for different stages of both the cardiac and respiratory cycles. A human subject was injected with 11.0 mCi 18-FDG. After allowing time for the isotope to clear the blood pool, emission data were acquired for 30 minutes. The respiratory cycle was divided into five gates, the cardiac cycle into three gates for a total of fifteen 47-plane emission datasets. An ungated transmission dataset was acquired to correct for the effects of attenuation. Each gate was separately reconstructed using standard filtered backprojection techniques. Data resulting from the five respiratory gates obtained during diastole will be discussed in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvA..93a2347L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvA..93a2347L"><span id="translatedtitle"><span class="hlt">Doubly</span> infinite separation of quantum information and communication</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Zi-Wen; Perry, Christopher; Zhu, Yechao; Koh, Dax Enshan; Aaronson, Scott</p> <p>2016-01-01</p> <p>We prove the existence of (one-way) communication tasks with a subconstant versus superconstant asymptotic gap, which we call "<span class="hlt">doubly</span> infinite," between their quantum information and communication complexities. We do so by studying the exclusion game [C. Perry et al., Phys. Rev. Lett. 115, 030504 (2015), 10.1103/PhysRevLett.115.030504] for which there exist instances where the quantum information complexity tends to zero as the size of the input n increases. By showing that the quantum communication complexity of these games scales at least logarithmically in n , we obtain our result. We further show that the established lower bounds and gaps still hold even if we allow a small probability of error. However in this case, the n -qubit quantum message of the zero-error strategy can be compressed polynomially.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26854706','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26854706"><span id="translatedtitle">Optomechanical Enhancement of <span class="hlt">Doubly</span> Resonant 2D Optical Nonlinearity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yi, Fei; Ren, Mingliang; Reed, Jason C; Zhu, Hai; Hou, Jiechang; Naylor, Carl H; Johnson, A T Charlie; Agarwal, Ritesh; Cubukcu, Ertugrul</p> <p>2016-03-01</p> <p>Emerging two-dimensional semiconductor materials possess a giant second order nonlinear response due to excitonic effects while the monolayer thickness of such active materials limits their use in practical nonlinear devices. Here, we report 3300 times optomechanical enhancement of second harmonic generation from a MoS2 monolayer in a <span class="hlt">doubly</span> resonant on-chip optical cavity. We achieve this by engineering the nonlinear light-matter interaction in a microelectro-mechanical system enabled optical frequency doubling device based on an electrostatically tunable Fabry-Perot microresonator. Our versatile optomechanical approach will pave the way for next generation efficient on-chip tunable light sources, sensors, and systems based on molecularly thin materials. PMID:26854706</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26728330','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26728330"><span id="translatedtitle"><span class="hlt">Doubly</span> Cavitand-Capped Porphyrin Capsule by Hydrogen Bonds.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kishimoto, Kazuki; Nakamura, Munechika; Kobayashi, Kenji</p> <p>2016-02-18</p> <p>The components of a 1:2 mixture of meso-tetrakis(4-dodecyl-3,5-dihydroxyphenyl)porphyrin (1) and a bowl-shaped tetrakis(4-pyridylethynyl)cavitand (2) in CDCl3 or C6 D6 self-assemble quantitatively into the <span class="hlt">doubly</span> cavitand-capped porphyrin capsule 2⋅1⋅2 through eight ArOH⋅⋅⋅Npy hydrogen bonds. Capsule 2⋅1⋅2 possesses two cavities divided by the porphyrin ring and encapsulates two molecules of 1-acetoxy-3,5-dimethoxybenzene (G) as a guest to form G/G@(2⋅1⋅2). Remarkable solvent effect was observed, in which the apparent association constant of 2⋅1⋅2 with G in C6 D6 was much greater than that in CDCl3. PMID:26728330</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26854706','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26854706"><span id="translatedtitle">Optomechanical Enhancement of <span class="hlt">Doubly</span> Resonant 2D Optical Nonlinearity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yi, Fei; Ren, Mingliang; Reed, Jason C; Zhu, Hai; Hou, Jiechang; Naylor, Carl H; Johnson, A T Charlie; Agarwal, Ritesh; Cubukcu, Ertugrul</p> <p>2016-03-01</p> <p>Emerging two-dimensional semiconductor materials possess a giant second order nonlinear response due to excitonic effects while the monolayer thickness of such active materials limits their use in practical nonlinear devices. Here, we report 3300 times optomechanical enhancement of second harmonic generation from a MoS2 monolayer in a <span class="hlt">doubly</span> resonant on-chip optical cavity. We achieve this by engineering the nonlinear light-matter interaction in a microelectro-mechanical system enabled optical frequency doubling device based on an electrostatically tunable Fabry-Perot microresonator. Our versatile optomechanical approach will pave the way for next generation efficient on-chip tunable light sources, sensors, and systems based on molecularly thin materials.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22257206','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22257206"><span id="translatedtitle">Nonsnaking <span class="hlt">doubly</span> diffusive convectons and the twist instability</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Beaume, Cédric Knobloch, Edgar; Bergeon, Alain</p> <p>2013-11-15</p> <p><span class="hlt">Doubly</span> diffusive convection in a three-dimensional horizontally extended domain with a square cross section in the vertical is considered. The fluid motion is driven by horizontal temperature and concentration differences in the transverse direction. When the buoyancy ratio N = −1 and the Rayleigh number is increased the conduction state loses stability to a subcritical, almost two-dimensional roll structure localized in the longitudinal direction. This structure exhibits abrupt growth in length near a particular value of the Rayleigh number but does not snake. Prior to this filling transition the structure becomes unstable to a secondary twist instability generating a pair of stationary, spatially localized zigzag states. In contrast to the primary branch these states snake as they grow in extent and eventually fill the whole domain. The origin of the twist instability and the properties of the resulting localized structures are investigated for both periodic and no-slip boundary conditions in the extended direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21075676','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21075676"><span id="translatedtitle"><span class="hlt">Doubly</span> ordered superconducting state in a doped antiferromagnet</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Belyavskii, V. I. Kopaev, Yu. V.; Tuan, Nguyen Ngoc</p> <p>2007-10-15</p> <p>In a weakly doped quasi-two-dimensional antiferromagnet with a Fermi contour in the form of small pockets, the Coulomb repulsion gives rise to a <span class="hlt">doubly</span> ordered superconducting state of coexisting condensates with a large pair momentum and a zero one. The pairing with the large momentum determines the superconducting transition temperature, below which the order with zero momentum coexists as an induced order until the temperature corresponding to the initiation of the phonon pairing mechanism is reached. The superconductivity-induced orbital current density wave eliminates the pairing-repulsion-caused zero points from the two-gap quasiparticle spectrum and leads to a deviation of the relative phase of the superconducting order parameter components from {pi}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26595911','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26595911"><span id="translatedtitle"><span class="hlt">Doubly</span> Sparse Relevance Vector Machine for Continuous Facial Behavior Estimation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kaltwang, Sebastian; Todorovic, Sinisa; Pantic, Maja</p> <p>2016-09-01</p> <p>Certain inner feelings and physiological states like pain are subjective states that cannot be directly measured, but can be estimated from spontaneous facial expressions. Since they are typically characterized by subtle movements of facial parts, analysis of the facial details is required. To this end, we formulate a new regression method for continuous estimation of the intensity of facial behavior interpretation, called <span class="hlt">Doubly</span> Sparse Relevance Vector Machine (DSRVM). DSRVM enforces double sparsity by jointly selecting the most relevant training examples (a.k.a. relevance vectors) and the most important kernels associated with facial parts relevant for interpretation of observed facial expressions. This advances prior work on multi-kernel learning, where sparsity of relevant kernels is typically ignored. Empirical evaluation on challenging Shoulder Pain videos, and the benchmark DISFA and SEMAINE datasets demonstrate that DSRVM outperforms competing approaches with a multi-fold reduction of running times in training and testing. PMID:26595911</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17280272','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17280272"><span id="translatedtitle"><span class="hlt">Doubly</span> magic nucleus (108)(270)Hs162.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dvorak, J; Brüchle, W; Chelnokov, M; Dressler, R; Düllmann, Ch E; Eberhardt, K; Gorshkov, V; Jäger, E; Krücken, R; Kuznetsov, A; Nagame, Y; Nebel, F; Novackova, Z; Qin, Z; Schädel, M; Schausten, B; Schimpf, E; Semchenkov, A; Thörle, P; Türler, A; Wegrzecki, M; Wierczinski, B; Yakushev, A; Yeremin, A</p> <p>2006-12-15</p> <p>Theoretical calculations predict 270Hs (Z=108, N=162) to be a <span class="hlt">doubly</span> magic deformed nucleus, decaying mainly by alpha-particle emission. In this work, based on a rapid chemical isolation of Hs isotopes produced in the 26Mg+248Cm reaction, we observed 15 genetically linked nuclear decay chains. Four chains were attributed to the new nuclide 270Hs, which decays by alpha-particle emission with Qalpha=9.02+/-0.03 MeV to 266Sg which undergoes spontaneous fission with a half-life of 444(-148)(+444) ms. A production cross section of about 3 pb was measured for 270Hs. Thus, 270Hs is the first nucleus for which experimental nuclear decay properties have become available for comparison with theoretical predictions of the N=162 shell stability. PMID:17280272</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22028290','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22028290"><span id="translatedtitle"><span class="hlt">Excitation</span> of a magnetospheric maser through modification of the Earth's ionosphere by <span class="hlt">high</span>-power HF radio emission from a ground-based transmitter</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Markov, G. A. Belov, A. S.; Frolov, V. L.; Rapoport, V. O.; Parrot, M.</p> <p>2010-01-15</p> <p>A method for controlled <span class="hlt">excitation</span> of a magnetospheric maser through the production of artificial density ducts by <span class="hlt">high</span>-power HF radio emission from the Earth's surface has been proposed and implemented in an in-situ experiment. Artificial density ducts allow one to affect the maser resonator system and the <span class="hlt">excitation</span> and propagation of low-frequency electromagnetic waves in a disturbed magnetic flux tube. The experimental data presented here were obtained at the mid-latitude Sura heating facility. The characteristics of electromagnetic and plasma disturbances at outer-ionosphere altitudes were measured using the onboard equipment of the DEMETER satellite as it passed through the magnetic flux tube rested on the region of intense generation of artificial ionospheric turbulence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750017928','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750017928"><span id="translatedtitle">Effect of damping on <span class="hlt">excitability</span> of <span class="hlt">high</span>-order normal modes. [for a large space telescope spacecraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Merchant, D. H.; Gates, R. M.; Straayer, J. W.</p> <p>1975-01-01</p> <p>The effect of localized structural damping on the <span class="hlt">excitability</span> of higher-order large space telescope spacecraft modes is investigated. A preprocessor computer program is developed to incorporate Voigt structural joint damping models in a finite-element dynamic model. A postprocessor computer program is developed to select critical modes for low-frequency attitude control problems and for higher-frequency fine-stabilization problems. The selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensor, and on image-plane motions due to sinusoidal or random PSD force and torque inputs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1057886','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1057886"><span id="translatedtitle">Probing the fundamental limit of niobium in <span class="hlt">high</span> radiofrequency fields by dual mode <span class="hlt">excitation</span> in superconducting radiofrequency cavities</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Eremeev, Grigory; Geng, Rongli; Palczewski, Ari</p> <p>2011-07-01</p> <p>We have studied thermal breakdown in several multicell superconducting radiofrequency cavity by simultaneous <span class="hlt">excitation</span> of two TM{sub 010} passband modes. Unlike measurements done in the past, which indicated a clear thermal nature of the breakdown, our measurements present a more complex picture with interplay of both thermal and magnetic effects. JLab LG-1 that we studied was limited at 40.5 MV/m, corresponding to B{sub peak} = 173 mT, in 8{pi}/9 mode. Dual mode measurements on this quench indicate that this quench is not purely magnetic, and so we conclude that this field is not the fundamental limit in SRF cavities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20161511','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20161511"><span id="translatedtitle">Improving efficiency and robustness of the <span class="hlt">doubly</span> robust estimator for a population mean with incomplete data.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cao, Weihua; Tsiatis, Anastasios A; Davidian, Marie</p> <p>2009-09-01</p> <p>Considerable recent interest has focused on <span class="hlt">doubly</span> robust estimators for a population mean response in the presence of incomplete data, which involve models for both the propensity score and the regression of outcome on covariates. The usual <span class="hlt">doubly</span> robust estimator may yield severely biased inferences if neither of these models is correctly specified and can exhibit nonnegligible bias if the estimated propensity score is close to zero for some observations. We propose alternative <span class="hlt">doubly</span> robust estimators that achieve comparable or improved performance relative to existing methods, even with some estimated propensity scores close to zero. PMID:20161511</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23779198','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23779198"><span id="translatedtitle">Direct observation of low energy nuclear spin <span class="hlt">excitations</span> in HoCrO3 by <span class="hlt">high</span> resolution neutron spectroscopy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chatterji, T; Jalarvo, N; Kumar, C M N; Xiao, Y; Brückel, Th</p> <p>2013-07-17</p> <p>We have investigated low energy nuclear spin <span class="hlt">excitations</span> in the strongly correlated electron compound HoCrO3. We observe clear inelastic peaks at E = 22.18 ± 0.04 μeV in both energy loss and gain sides. The energy of the inelastic peaks remains constant in the temperature range 1.5-40 K at which they are observed. The intensity of the inelastic peak increases at first with increasing temperature and then decreases at higher temperatures. The temperature dependence of the energy and intensity of the inelastic peaks is very unusual compared to that observed in other Nd, Co, V and also simple Ho compounds. Huge quasielastic scattering appears at higher temperatures presumably due to the fluctuating electronic moments of the Ho ions that get increasingly disordered at higher temperatures. The strong quasielastic scattering may also originate in the first Ho crystal-field <span class="hlt">excitations</span> at about 1.5 meV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016OptMa..54...45L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016OptMa..54...45L"><span id="translatedtitle"><span class="hlt">High</span> photoluminescence stability of CaGa4O7:Eu3+ red phosphor in wide <span class="hlt">excitation</span> intensity interval</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leanenia, M. S.; Lutsenko, E. V.; Rzheutski, M. V.; Yablonskii, G. P.; Naghiyev, T. G.; Ganbarova, H. B.; Tagiev, O. B.</p> <p>2016-04-01</p> <p>The photoluminescence (PL) of CaGa4O7 compound doped with Eu3+ ions is studied. It is shown that room temperature emission spectrum of CaGa4O7 compound consists of groups of lines in the red spectral region, caused by electronic transitions 5D0 → 7Fj (j = 1, 2, 3, 4) in Eu3+ ions with the most intensive lines at 612 nm and 615 nm. It is evaluated that low local symmetry of Eu3+ ion appears in the presence of several lines for each transitions. The PL decay constants were found to be in the range of 1.1-1.3 ms. Non-exponential rise was observed in the beginning of PL kinetics and assumed with energy transfer between Eu3+ ions in different sites in host lattice. Weak thermal quenching is shown in the temperature range of 10-300 K. Extreme stability of PL spectra and efficiency in a wide <span class="hlt">excitation</span> intensity range of 104-108 W/cm2 were achieved. A slight emission efficiency reversible droop by only 25% is found to be at the <span class="hlt">excitation</span> intensities from 2 · 107 W/cm2 to 108 W/cm2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AIPC.1012..291V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AIPC.1012..291V"><span id="translatedtitle">Coulomb <span class="hlt">Excitation</span> of the N = 50 nucleus 80Zn</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van de Walle, J.; Aksouh, F.; Ames, F.; Behrens, T.; Bildstein, V.; Blazhev, A.; Cederkäll, J.; Clément, E.; Cocolios, T. E.; Davinson, T.; Delahaye, P.; Eberth, J.; Ekström, A.; Fedorov, D. V.; Fedosseev, V. N.; Fraile, L. M.; Franchoo, S.; Gernhauser, R.; Georgiev, G.; Habs, D.; Heyde, K.; Huber, G.; Huyse, M.; Ibrahim, F.; Ivanov, O.; Iwanicki, J.; Jolie, J.; Kester, O.; Köster, U.; Kröll, T.; Krücken, R.; Lauer, M.; Lisetskiy, A. F.; Lutter, R.; Marsh, B. A.; Mayet, P.; Niedermaier, O.; Nilsson, T.; Pantea, M.; Perru, O.; Raabe, R.; Reiter, P.; Sawicka, M.; Scheit, H.; Schrieder, G.; Schwalm, D.; Seliverstov, M. D.; Sieber, T.; Sletten, G.; Smirnova, N.; Stanoiu, M.; Stefanescu, I.; Thomas, J.-C.; Valiente-Dobón, J. J.; van Duppen, P.; Verney, D.; Voulot, D.; Warr, N.; Weisshaar, D.; Wenander, F.; Wolf, B. H.; Zielińska, M.</p> <p>2008-05-01</p> <p>Neutron rich Zinc isotopes, including the N = 50 nucleus 80Zn, were produced and post-accelerated at the Radioactive Ion Beam (RIB) facility REX-ISOLDE (CERN). Low-energy Coulomb <span class="hlt">excitation</span> was induced on these isotopes after post-acceleration, yielding B(E2) strengths to the first <span class="hlt">excited</span> 2+ states. For the first time, an <span class="hlt">excited</span> state in 80Zn was observed and the 21+ state in 78Zn was established. The measured B(E2,21+-->01+) values are compared to two sets of large scale shell model calculations. Both calculations reproduce the observed B(E2) systematics for the full Zinc isotopic chain. The results for N = 50 isotones indicate a good N = 50 shell closure and a strong Z = 28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the <span class="hlt">doubly</span> magic nucleus 78Ni.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013JChPh.139d4104C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013JChPh.139d4104C&link_type=ABSTRACT"><span id="translatedtitle">A novel Gaussian Binning (1GB) analysis of vibrational state distributions in <span class="hlt">highly</span> <span class="hlt">excited</span> H2O from reactive quenching of OH* by H2</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Conte, Riccardo; Fu, Bina; Kamarchik, Eugene; Bowman, Joel M.</p> <p>2013-07-01</p> <p>As shown in experiments by Lester and co-workers [J. Chem. Phys. 110, 11117 (1999)], 10.1063/1.479053, the reactive quenching of OH* by H_2 produces <span class="hlt">highly</span> <span class="hlt">excited</span> H_2O. Previous limited analysis of quasiclassical trajectory calculations using standard Histogram Binning (HB) was reported [B. Fu, E. Kamarchik, and J. M. Bowman, J. Chem. Phys. 133, 164306 (2010)], 10.1063/1.3488167. Here, we examine the quantized internal state distributions of H_2O in more detail, using two versions of Gaussian Binning (denoted 1GB). In addition to the standard version of 1GB, which relies on the harmonic energies of the states (1GB-H), we propose a new and more accurate technique based on exact quantum vibrational energies (1GB-EQ). Data from about 42 000 trajectories from previous calculations that give <span class="hlt">excited</span> water molecules are used in the two versions of 1GB as well as HB. For the vibrationally hot molecules considered in this study, the classical internal energy distribution serves as a benchmark to estimate the accuracy of the different binning methods analyzed. The 1GB discretization methods, especially the one using exact quantum energies, reconstruct the classical distribution much more accurately than HB and also the original, more elaborate Gaussian Binning method. Detailed quantum state distributions are presented for pure overtone <span class="hlt">excitations</span> as well as several antisymmetric stretch distributions. The latter are focused on because the antisymmetric stretch has the largest emission oscillator strength of the three water modes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27376560','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27376560"><span id="translatedtitle">808 nm-<span class="hlt">excited</span> upconversion nanoprobes with low heating effect for targeted magnetic resonance imaging and <span class="hlt">high</span>-efficacy photodynamic therapy in HER2-overexpressed breast cancer.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zeng, Leyong; Pan, Yuanwei; Zou, Ruifen; Zhang, Jinchao; Tian, Ying; Teng, Zhaogang; Wang, Shouju; Ren, Wenzhi; Xiao, Xueshan; Zhang, Jichao; Zhang, Lili; Li, Aiguo; Lu, Guangming; Wu, Aiguo</p> <p>2016-10-01</p> <p>To avoid the overheating effect of <span class="hlt">excitation</span> light and improve the efficacy of photodynamic therapy (PDT) of upconversion nanoplatform, a novel nanoprobe based on 808 nm-<span class="hlt">excited</span> upconversion nanocomposites (T-UCNPs@Ce6@mSiO2) with low heating effect and deep penetration has been successfully constructed for targeted upconversion luminescence, magnetic resonance imaging (MRI) and <span class="hlt">high</span>-efficacy PDT in HER2-overexpressed breast cancer. In this nanocomposite, photosensitizers (Ce6) were covalently conjugated inside of mesoporous silica to enhance the PDT efficacy by shortening the distance of fluorescence resonance energy transfer and to decrease the cytotoxicity by preventing the undesired leakage of Ce6. Compared with UCNPs@mSiO2@Ce6, UCNPs@Ce6@mSiO2 greatly promoted the singlet oxygen generation and amplified the PDT efficacy under the <span class="hlt">excitation</span> of 808 nm laser. Importantly, the designed nanoprobe can greatly improve the uptake of HER2-positive cells and tumors by modifying the site-specific peptide, and the in vivo experiments showed excellent MRI and PDT via intravenous injection by modeling MDA-MB-435 tumor-bearing nude mice. Our strategy may provide an effective solution for overcoming the heating effect and improving the PDT efficacy of upconversion nanoprobes, and has potential application in visualized theranostics of HER2-overexpressed breast cancer. PMID:27376560</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27376560','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27376560"><span id="translatedtitle">808 nm-<span class="hlt">excited</span> upconversion nanoprobes with low heating effect for targeted magnetic resonance imaging and <span class="hlt">high</span>-efficacy photodynamic therapy in HER2-overexpressed breast cancer.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zeng, Leyong; Pan, Yuanwei; Zou, Ruifen; Zhang, Jinchao; Tian, Ying; Teng, Zhaogang; Wang, Shouju; Ren, Wenzhi; Xiao, Xueshan; Zhang, Jichao; Zhang, Lili; Li, Aiguo; Lu, Guangming; Wu, Aiguo</p> <p>2016-10-01</p> <p>To avoid the overheating effect of <span class="hlt">excitation</span> light and improve the efficacy of photodynamic therapy (PDT) of upconversion nanoplatform, a novel nanoprobe based on 808 nm-<span class="hlt">excited</span> upconversion nanocomposites (T-UCNPs@Ce6@mSiO2) with low heating effect and deep penetration has been successfully constructed for targeted upconversion luminescence, magnetic resonance imaging (MRI) and <span class="hlt">high</span>-efficacy PDT in HER2-overexpressed breast cancer. In this nanocomposite, photosensitizers (Ce6) were covalently conjugated inside of mesoporous silica to enhance the PDT efficacy by shortening the distance of fluorescence resonance energy transfer and to decrease the cytotoxicity by preventing the undesired leakage of Ce6. Compared with UCNPs@mSiO2@Ce6, UCNPs@Ce6@mSiO2 greatly promoted the singlet oxygen generation and amplified the PDT efficacy under the <span class="hlt">excitation</span> of 808 nm laser. Importantly, the designed nanoprobe can greatly improve the uptake of HER2-positive cells and tumors by modifying the site-specific peptide, and the in vivo experiments showed excellent MRI and PDT via intravenous injection by modeling MDA-MB-435 tumor-bearing nude mice. Our strategy may provide an effective solution for overcoming the heating effect and improving the PDT efficacy of upconversion nanoprobes, and has potential application in visualized theranostics of HER2-overexpressed breast cancer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999JAP....85.8011W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999JAP....85.8011W"><span id="translatedtitle">Near infrared <span class="hlt">excited</span> micro-Raman spectra of 4:1 methanol-ethanol mixture and ruby fluorescence at <span class="hlt">high</span> pressure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, X. B.; Shen, Z. X.; Tang, S. H.; Kuok, M. H.</p> <p>1999-06-01</p> <p>Near infrared (NIR) lasers, as a new <span class="hlt">excitation</span> source for Raman spectroscopy, has shown its unique advantages and is being increasingly used for some special samples, such as those emitting strong fluorescence in the visible region. This article focuses on some issues related to <span class="hlt">high</span>-pressure micro-Raman spectroscopy using NIR <span class="hlt">excitation</span> source. The Raman spectra of 4:1 methanol-ethanol mixture (4:1 M-E) show a linear variation in both Raman shifts and linewidths under pressure up to 18 GPa. This result is useful in distinguishing Raman scattering of samples from that of the alcohol mixture, an extensively used pressure-transmitting medium. The R1 fluorescence in the red region induced by two-photon absorption of the NIR laser is strong enough to be used as pressure scale. The frequency and line width of the R1 lines are very sensitive to pressure change and the glass transition of the pressure medium. Our results manifest that it is reliable and convenient to use NIR induced two-photon <span class="hlt">excited</span> fluorescence of ruby for both pressure calibration and distribution of pressure in the 4:1 M-E pressure transmitting medium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/486170','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/486170"><span id="translatedtitle">Multi-band Bloch equations and gain spectra of <span class="hlt">highly</span> <span class="hlt">excited</span> II-VI semiconductor quantum wells</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Girndt, A.; Jahnke, F.; Knorr, A.; Koch, S.W.; Chow, W.W.</p> <p>1997-04-21</p> <p>Quasi-equilibrium <span class="hlt">excitation</span> dependent optical probe spectra of II-VI semiconductor quantum wells at room temperature are investigated within the framework of multi-band semiconductor Bloch equations. The calculations include correlation effects beyond the Hartree-Fock level which describe dephasing, interband Coulomb correlations and band-gap renormalization in second Born approximation. In addition to the carrier-Coulomb interaction, the influence of carrier-phonon scattering and inhomogeneous broadening is considered. The explicit calculation of single particle properties like band structure and dipole matrix elements using k {center_dot} p theory makes it possible to investigate various II-VI material combinations. Numerical results are presented for CdZnSe/ZnSe and CdZnSe/MnZnSSe semiconductor quantum-well systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...585A.121F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...585A.121F"><span id="translatedtitle">Radiative rates for forbidden M1 and E2 transitions of astrophysical interest in <span class="hlt">doubly</span> ionized iron-peak elements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fivet, V.; Quinet, P.; Bautista, M. A.</p> <p>2016-01-01</p> <p>Aims: Accurate and reliable atomic data for lowly ionized Fe-peak species (Sc, Ti, V, Cr, Mn, Fe, Co, and Ni) are of paramount importance for analyzing the <span class="hlt">high</span>-resolution astrophysical spectra currently available. The third spectra of several iron group elements have been observed in different galactic sources, such as Herbig-Haro objects in the Orion Nebula and stars like Eta Carinae. However, forbidden M1 and E2 transitions between low-lying metastable levels of <span class="hlt">doubly</span> charged iron-peak ions have been investigated very little so far, and radiative rates for those lines remain sparse or nonexistent. We attempt to fill that gap and provide transition probabilities for the most important forbidden lines of all <span class="hlt">doubly</span> ionized iron-peak elements. Methods: We carried out a systematic study of the electronic structure of <span class="hlt">doubly</span> ionized Fe-peak species. The magnetic dipole (M1) and electric quadrupole (E2) transition probabilities were computed using the pseudo-relativistic Hartree-Fock (HFR) code of Cowan and the central Thomas-Fermi-Dirac-Amaldi potential approximation implemented in AUTOSTRUCTURE. This multiplatform approach allowed for consistency checks and intercomparison and has proven very useful in many previous works for estimating the uncertainties affecting the radiative data. Results: We present transition probabilities for the M1 and E2 forbidden lines depopulating the metastable even levels belonging to the 3dk and 3dk-14s configurations in Sc III (k = 1), Ti III (k = 2), V III (k = 3), Cr III (k = 4), Mn III (k = 5), Fe III (k = 6), Co III (k = 7), and Ni III (k = 8).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22415628','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22415628"><span id="translatedtitle">Equation-of-motion coupled-cluster method for <span class="hlt">doubly</span> ionized states with spin-orbit coupling</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, Zhifan; Hu, Shu; Guo, Jingwei; Wang, Fan</p> <p>2015-04-14</p> <p>In this work, we report implementation of the equation-of-motion coupled-cluster method for <span class="hlt">doubly</span> ionized states (EOM-DIP-CC) with spin-orbit coupling (SOC) using a closed-shell reference. Double ionization potentials (DIPs) are calculated in the space spanned by 2h and 3h1p determinants with the EOM-DIP-CC approach at the CC singles and doubles level (CCSD). Time-reversal symmetry together with spatial symmetry is exploited to reduce computational effort. To circumvent the problem of unstable dianion references when diffuse basis functions are included, nuclear charges are scaled. Effect of this stabilization potential on DIPs is estimated based on results from calculations using a small basis set without diffuse basis functions. DIPs and <span class="hlt">excitation</span> energies of some low-lying states for a series of open-shell atoms and molecules containing heavy elements with two unpaired electrons have been calculated with the EOM-DIP-CCSD approach. Results show that this approach is able to afford a reliable description on SOC splitting. Furthermore, the EOM-DIP-CCSD approach is shown to provide reasonable <span class="hlt">excitation</span> energies for systems with a dianion reference when diffuse basis functions are not employed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22413280','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22413280"><span id="translatedtitle"><span class="hlt">Excitability</span> in the H{sub 2}+O{sub 2} reaction on a Rh(110) surface induced by <span class="hlt">high</span> coverages of coadsorbed potassium</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rafti, Matías; Imbihl, Ronald</p> <p>2014-12-07</p> <p>By means of photoemission electron microscopy as spatially resolving method, the effect of <span class="hlt">high</span> coverages of coadsorbed potassium (0.16 ≤ θ{sub K} ≤ 0.21) on the dynamical behavior of the H{sub 2} + O{sub 2} reaction over a Rh(110) surface was investigated. We observe that the originally bistable system is transformed into an <span class="hlt">excitable</span> system as evidenced by the formation of target patterns and spiral waves. At K coverages close to saturation (θ{sub K} ≈ 0.21) mass transport of potassium with pulses is seen.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/37195','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/37195"><span id="translatedtitle">Computing ferrite core losses at <span class="hlt">high</span> frequency by finite elements method including temperature influence</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ahmed, B.; Ahmad, J.; Guy, G.</p> <p>1994-09-01</p> <p>A finite elements method coupled with the Preisach model of hysteresis is used to compute-the ferrite losses in medium power transformers (10--60 kVA) working at relatively <span class="hlt">high</span> frequencies (20--60 kHz) and with an <span class="hlt">excitation</span> level of about 0.3 Tesla. The dynamic evolution of the permeability is taken into account. The simple and <span class="hlt">doubly</span> cubic spline functions are used to account for temperature effects respectively on electric and on magnetic parameters of the ferrite cores. The results are compared with test data obtained with 3C8 and B50 ferrites at different frequencies.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. Their policies may differ from this site.</small> </div> </center> <div id="footer-wrapper"> <div class="footer-content"> <div id="footerOSTI" class=""> <div class="row"> <div class="col-md-4 text-center col-md-push-4 footer-content-center"><small><a href="http://www.science.gov/disclaimer.html">Privacy and Security</a></small> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center col-md-pull-4 footer-content-left"> <img src="https://www.osti.gov/images/DOE_SC31.png" alt="U.S. Department of Energy" usemap="#doe" height="31" width="177"><map style="display:none;" name="doe" id="doe"><area shape="rect" coords="1,3,107,30" href="http://www.energy.gov" alt="U.S. Deparment of Energy"><area shape="rect" coords="114,3,165,30" href="http://www.science.energy.gov" alt="Office of Science"></map> <a ref="http://www.osti.gov" style="margin-left: 15px;"><img src="https://www.osti.gov/images/footerimages/ostigov53.png" alt="Office of Scientific and Technical Information" height="31" width="53"></a> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center footer-content-right"> <a href="http://www.osti.gov/nle"><img src="https://www.osti.gov/images/footerimages/NLElogo31.png" alt="National Library of Energy" height="31" width="79"></a> <a href="http://www.science.gov"><img src="https://www.osti.gov/images/footerimages/scigov77.png" alt="science.gov" height="31" width="98"></a> <a href="http://worldwidescience.org"><img src="https://www.osti.gov/images/footerimages/wws82.png" alt="WorldWideScience.org" height="31" width="90"></a> </div> </div> </div> </div> </div> <p><br></p> </div><!-- container --> </body> </html>