WorldWideScience

Sample records for strong fuv emissions

  1. A PILOT DEEP SURVEY FOR X-RAY EMISSION FROM fuvAGB STARS

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, R. [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States); Sanz-Forcada, J.; Sánchez Contreras, C. [Astrobiology Center (CSIC-INTA), ESAC campus, E-28691 Villanueva de la Canada, Madrid (Spain); Stute, M. [Institute for Astronomy and Astrophysics, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 10, D-72076, Tübingen (Germany)

    2015-09-01

    We report the results of a pilot survey for X-ray emission from a newly discovered class of AGB stars with far-ultraviolet excesses (fuvAGB stars) using XMM-Newton and Chandra. We detected X-ray emission in three of six fuvAGB stars observed—the X-ray fluxes are found to vary in a stochastic or quasi-periodic manner on roughly hour-long timescales, and simultaneous UV observations using the Optical Monitor on XMM for these sources show similar variations in the UV flux. These data, together with previous studies, show that X-ray emission is found only in fuvAGB stars. From modeling the spectra, we find that the observed X-ray luminosities are ∼(0.002–0.2) L{sub ⊙} and the X-ray-emitting plasma temperatures are ∼(35–160) × 10{sup 6} K. The high X-ray temperatures argue against the emission arising in stellar coronae, or directly in an accretion shock, unless it occurs on a WD companion. However, none of the detected objects is a known WD-symbiotic star, suggesting that if WD companions are present, they are relatively cool (<20,000 K). In addition, the high X-ray luminosities specifically argue against emission originating in the coronae of main-sequence companions. We discuss several models for the X-ray emission and its variability and find that the most likely scenario for the origin of the X-ray (and FUV) emission involves accretion activity around a companion star, with confinement by strong magnetic fields associated with the companion and/or an accretion disk around it.

  2. Relations Between FUV Excess and Coronal Soft X-Ray Emission Among Dwarf Stars

    Science.gov (United States)

    Smith, Graeme H.; Hargrave, Mason; Eckholm, Elliot

    2017-11-01

    The far-ultraviolet magnitudes of late-F, G and early-K dwarfs with (B - V) ⩾ 0.50 as measured by the GALEX satellite are shown to correlate with soft X-ray luminosity. This result indicates that line and continuum emission from stellar active regions make significant contributions to the flux in the GALEX FUV band for late-F, G and K dwarfs. By contrast, detection of a correlation between FUV brightness and soft X-ray luminosity among early-F dwarfs requires subtraction of the photospheric component from the FUV flux. The range in (B - V) among F and G dwarfs over which a correlation between uncorrected FUV magnitude and X-ray luminosity is detected coincides with the range in colour over which coronal and chromospheric emission correlates with stellar rotation.

  3. CCM in the FUV

    Science.gov (United States)

    Cartledge, S. I. B.; Clayton, G. C.; Gordon, K. D.

    2005-12-01

    Over 90% of Milky Way extinction curves sampled from IR through UV wavelengths (UV coverage by IUE) conform to the CCM family of curves based on R(V), a single parameter linked to grain size. The far-ultraviolet (FUV) portion of this formulation, however, was based only on a few sight lines observed by Copernicus, and it has recently been shown that in certain cases CCM does not predict extinction in the FUV as accurately as it does at longer wavelengths. In this poster paper, we present preliminary results from our examination of the agreement between all publicly-available FUSE FUV spectra of reddened O and B stars and their corresponding extinction curves inferred from longer wavelength fluxes. The eventual goal of our project is to reformulate CCM, particularly in the FUV where we have compiled more than 90 sight lines observed by FUSE. We are also exploring correlations between bulk sight line properties and the form of the reconstituted CCM curves.

  4. The Amazing COS FUV (1320 - 1460 A) Spectrum of (lambda) Vel (K4Ib-II)

    Science.gov (United States)

    Carpenter, Kenneth

    2010-01-01

    The FUV spectrum (1320-1460 A) of the K4 lb-11 supergiant (lambda) Vel was observed with the Cosmic Origins Spectrograph (COS) on HST, as part of the Ayres and Redfield Cycle 17 SNAP program "SNAPing Coronal Iron". This spectrum covers a region not previously recorded in (lambda) Vel at high resolution and, in a mere 20 minutes of exposure, reveals a treasure trove of information. It shows a wide variety of strong emission lines, superposed on a bright continuum, with contributions from both atomic and molecular species. Multiple absorptions, including numerous Ni II and Fe II lines, are visible over this continuum, which is likely generated in the chromosphere of the star. Evidence of the stellar wind is seen in the P Cygni profiles of the CII lines near 1335 A and the results of fluorescence processes are visible throughout the region. The spectrum has remarkable similarities to that of (alpha) Boo (K1.5 III), but significant differences as well, including substantial FUV continuum emission, reminiscent of the M2 Iab supergiant (alpha) Ori, but minus the CO fundamental absorption bands seen in the spectrum of the latter star. However, fluoresced CO emission is present, as in the K-giant stars (alpha) Boo and (alpha) Tau (K5 III). The presence of hot plasma in the atmosphere of the star, indicated by previous GHRS observations of Si III] and C III] lines near 1900 A and FUSE observations of O VI 1032 A, is further confirmed by the detection in this COS spectrum of the Si IV UV 1 lines near 1400 A, though both lines are contaminated by overlying fluorescent H2 emission. We present the details of this spectrum, in comparison with stars of similar temperature or luminosity and discuss the implications for the structure of, and the radiative processes active in, the outer atmospheres of these stars.

  5. A SNAPshot of the FUV (1320 - 1460 A) Spectrum of Lambda Vel (K4Ib-II)

    Science.gov (United States)

    Carpenter, Kenneth G.

    2010-01-01

    The FUV spectrum (l330-1460A) of the K4Ib-II supergiant Lambda Vel was observed with the Cosmic Origins Spectrograph (COS) on HST, as part of the Ayres and Redfield Cycle 17 SNAP program "SNAPing Coronal Iron". This spectrum covers a region not previously seen in Lambda Vel at high resolution and reveals a rich emission-line spectrum superposed on a bright continuum, with contributions from a variety of atomic and molecular sources. Evidence of the stellar wind is seen in the P Cygni profiles of selected lines and the results of fluorescence processes are visible throughout the region. The spectrum has remarkable similarities to that of Alpha Boo (K1.5 III), but significant differences as well, including substantial FUV continuum emission, reminiscent of the M2 lab supergiant Alpha Ori, but minus the CO fundamental absorption bands seen in the latter star. However, fluoresced CO emission is present and strong, as in the K-giant stars Alpha Boo and Alpha Tau (K5 III). We present the details of this spectrum, in comparison to stars of similar temperature or luminosity and discuss the implications for the structure of and the radiative processes active in, the outer atmospheres of these stars.

  6. Strong blue emission from zinc hydroxide carbonate nanosheets

    International Nuclear Information System (INIS)

    Mao, Jing; Chen, Xuemin; Ling, Tao; Du, Xiwen

    2016-01-01

    Zinc hydroxide carbonate (ZHC) is a typical layered salt composed of zinc hydroxide layers separated with carbonate ions and water molecules. Studies of morphology control and the constitution of functional ZHC material with intercalated ions has been widely developed. Also, ZnO can be easily obtained by anneal treatment of ZHC, and the porous structure as synthesized had great potential in gas sensors, photocatalysts and dye-sensitized solar cells. However, the optical of ZHC have rarely been investigated. In our research, a strong blue emission of ZHC is reported. The effect of growth time, annealing treatment and modification of surfactants on blue emission have been systematically studied. Combined with information of interior effect of OH groups, crystal structure and electronegativity of surfactants, a possible emission mechanism of ZHC has been proposed.

  7. Anomalous radon emission as precursor of medium to strong earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Zoran, Maria [National Institute of R& D for Optoelectronics, MG5 Bucharest -Magurele, 077125 Romania (Romania)

    2016-03-25

    Anomalous radon (Rn{sup 222}) emissions enhanced by forthcoming earthquakes is considered to be a precursory phenomenon related to an increased geotectonic activity in seismic areas. Rock microfracturing in the Earth’s crust preceding a seismic rupture may cause local surface deformation fields, rock dislocations, charged particle generation and motion, electrical conductivity changes, radon and other gases emission, fluid diffusion, electrokinetic, piezomagnetic and piezoelectric effects as well as climate fluctuations. Space-time anomalies of radon gas emitted in underground water, soil and near the ground air weeks to days in the epicentral areas can be associated with the strain stress changes that occurred before the occurrence of medium and strong earthquakes. This paper aims to investigate temporal variations of radon concentration levels in air near or in the ground by the use of solid state nuclear track detectors (SSNTD) CR-39 and LR-115 in relation with some important seismic events recorded in Vrancea region, Romania.

  8. Highly concentrated zinc oxide nanocrystals sol with strong blue emission

    International Nuclear Information System (INIS)

    Vafaee, M.; Sasani Ghamsari, M.; Radiman, S.

    2011-01-01

    Highly concentrated ZnO sol was synthesized by an improved sol-gel method. Water was used as a modifier to control the sol-gel reaction and provide a way to increase the sol concentration. Concentration of ZnO in the prepared sol is higher than from other methods. Optical absorption and photoluminescence were used to investigate optical properties of the prepared sol. FTIR test was performed to study the influence of water on the compounds of as-prepared sol. The size and morphology of ZnO nanoparticles have been studied by HRTEM. The prepared colloidal ZnO nanocrystals have narrow size distribution (5-8 nm) and showed strong blue emission. The prepared sol has enough potential for optoelectronic applications. - Research highlights: → Novel sol-gel route has been employed to prepare highly concentrated ZnO colloidal nanocrystals. → Water has been used to control the sources of emission in synthesized material. → A strong blue luminescent material has been obtained.

  9. A Novel Method for Age Estimation in Solar-Type Stars Through GALEX FUV Magnitudes

    Science.gov (United States)

    Ho, Kelly; Subramonian, Arjun; Smith, Graeme; Shouru Shieh

    2018-01-01

    Utilizing an inverse association known to exist between Galaxy Evolution Explorer (GALEX) far ultraviolet (FUV) magnitudes and the chromospheric activity of F, G, and K dwarfs, we explored a method of age estimation in solar-type stars through GALEX FUV magnitudes. Sample solar-type star data were collected from refereed publications and filtered by B-V and absolute visual magnitude to ensure similarities in temperature and luminosity to the Sun. We determined FUV-B and calculated a residual index Q for all the stars, using the temperature-induced upper bound on FUV-B as the fiducial. Plotting current age estimates for the stars against Q, we discovered a strong and significant association between the variables. By applying a log-linear transformation to the data to produce a strong correlation between Q and loge Age, we confirmed the association between Q and age to be exponential. Thus, least-squares regression was used to generate an exponential model relating Q to age in solar-type stars, which can be used by astronomers. The Q-method of stellar age estimation is simple and more efficient than existing spectroscopic methods and has applications to galactic archaeology and stellar chemical composition analysis.

  10. GAS MOTION STUDY OF Lyα EMITTERS AT z ∼ 2 USING FUV AND OPTICAL SPECTRAL LINES ,

    International Nuclear Information System (INIS)

    Hashimoto, Takuya; Shimasaku, Kazuhiro; Nakajima, Kimihiko; Ouchi, Masami; Ono, Yoshiaki; Rauch, Michael; Janice Lee; Okamura, Sadanori

    2013-01-01

    We present the results of Magellan/MMIRS and Keck/NIRSPEC spectroscopy for five Lyα emitters (LAEs) at z ≅ 2.2 for which high-resolution FUV spectra from Magellan/MagE are available. We detect nebular emission lines including Hα on the individual basis and low-ionization interstellar (LIS) absorption lines in a stacked FUV spectrum, and measure average offset velocities of the Lyα line, Δv Lyα , and LIS absorption lines, Δv abs , with respect to the systemic velocity defined by the nebular lines. For a sample of eight z ∼ 2-3 LAEs without active galactic nucleus from our study and the literature, we obtain Δv Lyα = 175 ± 35 km s –1 , which is significantly smaller than that of Lyman-break Galaxies (LBGs), Δv Lyα ≅ 400 km s –1 . The stacked FUV spectrum gives Δv abs = –179 ± 73 km s –1 , comparable to that of LBGs. These positive Δv Lyα and negative Δv abs suggest that LAEs also have outflows. In contrast to LBGs, however, the LAEs' Δv Lyα is as small as |Δv abs |, suggesting low neutral hydrogen column densities. Such a low column density with a small number of resonant scattering may cause the observed strong Lyα emission of LAEs. We find an anti-correlation between Lyα equivalent width (EW) and Δv Lyα in a compilation of LAE and LBG samples. Although its physical origin is not clear, this anti-correlation result appears to challenge the hypothesis that a strong outflow, by means of a reduced number of resonant scattering, produces a large EW. If LAEs at z > 6 have similarly small Δv Lyα values, constraints on the reionization history derived from the Lyα transmissivity may need to be revised.

  11. GAS MOTION STUDY OF Ly{alpha} EMITTERS AT z {approx} 2 USING FUV AND OPTICAL SPECTRAL LINES {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Takuya; Shimasaku, Kazuhiro; Nakajima, Kimihiko [Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Ouchi, Masami; Ono, Yoshiaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Rauch, Michael; Janice Lee [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Okamura, Sadanori, E-mail: thashimoto@astron.s.u-tokyo.ac.jp [Department of Advanced Sciences, Faculty of Science and Engineering, Hosei University, 3-7-2 Kajino-cho, Koganei-shi, Tokyo 184-8584 (Japan)

    2013-03-01

    We present the results of Magellan/MMIRS and Keck/NIRSPEC spectroscopy for five Ly{alpha} emitters (LAEs) at z {approx_equal} 2.2 for which high-resolution FUV spectra from Magellan/MagE are available. We detect nebular emission lines including H{alpha} on the individual basis and low-ionization interstellar (LIS) absorption lines in a stacked FUV spectrum, and measure average offset velocities of the Ly{alpha} line, {Delta}v {sub Ly{alpha}}, and LIS absorption lines, {Delta}v {sub abs}, with respect to the systemic velocity defined by the nebular lines. For a sample of eight z {approx} 2-3 LAEs without active galactic nucleus from our study and the literature, we obtain {Delta}v {sub Ly{alpha}} = 175 {+-} 35 km s{sup -1}, which is significantly smaller than that of Lyman-break Galaxies (LBGs), {Delta}v {sub Ly{alpha}} {approx_equal} 400 km s{sup -1}. The stacked FUV spectrum gives {Delta}v {sub abs} = -179 {+-} 73 km s{sup -1}, comparable to that of LBGs. These positive {Delta}v {sub Ly{alpha}} and negative {Delta}v {sub abs} suggest that LAEs also have outflows. In contrast to LBGs, however, the LAEs' {Delta}v {sub Ly{alpha}} is as small as |{Delta}v {sub abs}|, suggesting low neutral hydrogen column densities. Such a low column density with a small number of resonant scattering may cause the observed strong Ly{alpha} emission of LAEs. We find an anti-correlation between Ly{alpha} equivalent width (EW) and {Delta}v {sub Ly{alpha}} in a compilation of LAE and LBG samples. Although its physical origin is not clear, this anti-correlation result appears to challenge the hypothesis that a strong outflow, by means of a reduced number of resonant scattering, produces a large EW. If LAEs at z > 6 have similarly small {Delta}v {sub Ly{alpha}} values, constraints on the reionization history derived from the Ly{alpha} transmissivity may need to be revised.

  12. New Geometric-distortion Solution for STIS FUV-MAMA

    Science.gov (United States)

    Sohn, S. Tony

    2018-04-01

    We derived a new geometric distortion solution for the STIS FUV-MAMA detector. To do this, positions of stars in 89 FUV-MAMA observations of NGC 6681 were compared to an astrometric standard catalog created using WFC3/UVIS imaging data to derive a fourth-order polynomial solution that transforms raw (x, y) positions to geometrically- corrected (x, y) positions. When compared to astrometric catalog positions, the FUV- MAMA position measurements based on the IDCTAB showed residuals with an RMS of ∼ 30 mas in each coordinate. Using the new IDCTAB, the RMS is reduced to ∼ 4 mas, or 0.16 FUV-MAMA pixels, in each coordinate. The updated IDCTAB is now being used in the HST STIS pipeline to process all STIS FUV-MAMA images.

  13. Global auroral conductance distribution due to electron and proton precipitation from IMAGE-FUV observations

    Directory of Open Access Journals (Sweden)

    V. Coumans

    2004-04-01

    Full Text Available The Far Ultraviolet (FUV imaging system on board the IMAGE satellite provides a global view of the north auroral region in three spectral channels, including the SI12 camera sensitive to Doppler shifted Lyman-α emission. FUV images are used to produce instantaneous maps of electron mean energy and energy fluxes for precipitated protons and electrons. We describe a method to calculate ionospheric Hall and Pedersen conductivities induced by auroral proton and electron ionization based on a model of interaction of auroral particles with the atmosphere. Different assumptions on the energy spectral distribution for electrons and protons are compared. Global maps of ionospheric conductances due to instantaneous observation of precipitating protons are calculated. The contribution of auroral protons in the total conductance induced by both types of auroral particles is also evaluated and the importance of proton precipitation is evaluated. This method is well adapted to analyze the time evolution of ionospheric conductances due to precipitating particles over the auroral region or in particular sectors. Results are illustrated with conductance maps of the north polar region obtained during four periods with different activity levels. It is found that the proton contribution to conductance is relatively higher during quiet periods than during substorms. The proton contribution is higher in the period before the onset and strongly decreases during the expansion phase of substorms. During a substorm which occurred on 28 April 2001, a region of strong proton precipitation is observed with SI12 around 14:00MLT at ~75° MLAT. Calculation of conductances in this sector shows that neglecting the protons contribution would produce a large error. We discuss possible effects of the proton precipitation on electron precipitation in auroral arcs. The increase in the ionospheric conductivity, induced by a former proton precipitation can reduce the potential drop

  14. Global auroral conductance distribution due to electron and proton precipitation from IMAGE-FUV observations

    Directory of Open Access Journals (Sweden)

    V. Coumans

    2004-04-01

    Full Text Available The Far Ultraviolet (FUV imaging system on board the IMAGE satellite provides a global view of the north auroral region in three spectral channels, including the SI12 camera sensitive to Doppler shifted Lyman-α emission. FUV images are used to produce instantaneous maps of electron mean energy and energy fluxes for precipitated protons and electrons. We describe a method to calculate ionospheric Hall and Pedersen conductivities induced by auroral proton and electron ionization based on a model of interaction of auroral particles with the atmosphere. Different assumptions on the energy spectral distribution for electrons and protons are compared. Global maps of ionospheric conductances due to instantaneous observation of precipitating protons are calculated. The contribution of auroral protons in the total conductance induced by both types of auroral particles is also evaluated and the importance of proton precipitation is evaluated. This method is well adapted to analyze the time evolution of ionospheric conductances due to precipitating particles over the auroral region or in particular sectors. Results are illustrated with conductance maps of the north polar region obtained during four periods with different activity levels. It is found that the proton contribution to conductance is relatively higher during quiet periods than during substorms. The proton contribution is higher in the period before the onset and strongly decreases during the expansion phase of substorms. During a substorm which occurred on 28 April 2001, a region of strong proton precipitation is observed with SI12 around 14:00MLT at ~75° MLAT. Calculation of conductances in this sector shows that neglecting the protons contribution would produce a large error. We discuss possible effects of the proton precipitation on electron precipitation in auroral arcs. The increase in the ionospheric conductivity, induced by a former proton precipitation can reduce the potential drop

  15. The FUV to Near-IR Morphologies of Luminous Infrared Galaxies in the Goals Sample

    Science.gov (United States)

    Petty, S. M.; Armus, L.; Charmandaris, V.; Evans, A. S.; Le Floc'h, E.; Bridge, C.; Díaz-Santos, T.; Howell, J. H.; Inami, H.; Psychogyios, A.; Stierwalt, S.; Surace, J. A.

    2014-12-01

    We compare the morphologies of a sample of 20 luminous infrared galaxies (LIRGs) from the Great Observatories All-sky LIRG Survey (GOALS) in the FUV, B, I, and H bands, using the Gini (G) and M20 parameters to quantitatively estimate the distribution and concentration of flux as a function of wavelength. Hubble Space Telescope (HST) images provide an average spatial resolution of ˜ 80 pc. While our LIRGs can be reliably classified as mergers across the entire range of wavelengths studied here, there is a clear shift toward more negative M20 (more bulge-dominated) and a less significant decrease in G values at longer wavelengths. We find no correlation between the derived FUV G-M20 parameters and the global measures of the IR to FUV flux ratio (IRX). Given the fine resolution in our HST data, this suggests either that the UV morphology and IRX are correlated on very small scales, or that the regions emitting the bulk of the IR emission emit almost no FUV light. We use our multi-wavelength data to simulate how merging LIRGs would appear from z˜ 0.5-3 in deep optical and near-infrared images such as the Hubble Ultra-Deep Field, and use these simulations to measure the G-M20 at these redshifts. Our simulations indicate a noticeable decrease in G, which flattens at z≥slant 2 by as much as 40%, resulting in mis-classifying our LIRGs as disk-like, even in the rest-frame FUV. The higher redshift values of M20 for the GOALS sources do not appear to change more than about 10% from the values at z˜ 0. The change in G-M20 is caused by the surface brightness dimming of extended tidal features and asymmetries, and also the decreased spatial resolution which reduced the number of individual clumps identified. This effect, seen as early as z˜ 0.5, could easily lead to an underestimate of the number of merging galaxies at high-redshift in the rest-frame FUV.

  16. Geometry and dynamics of particle emission from strongly deformed nuclei

    International Nuclear Information System (INIS)

    Aleshin, V.P.

    1995-01-01

    By using our semiclassical approach to particle evaporation from deformed nuclei, we analyze the heuristic models of particle emission from deformed nuclei which are used in the codes GANES, ALICE, and EVAP. The calculations revealed that the heuristic models are reasonable for particle energy spectra but fail, at large deformations, to describe the angular distributions

  17. Measurement of population inversion for FUV transitions in Kr-like Y IV in a high-current reflex discharge

    International Nuclear Information System (INIS)

    Fournier, K.B.; Shlyaptsev, V.N.; Goldstein, W.H.; Stutman, D.; Soukhanovskii, V.; Finkenthal, M.; May, M.J.; Vero, R.

    2000-01-01

    Kr-like ions are good candidates for FUV lasing since they can be produced in plasmas quite easily. We present results from a spectroscopic investigation of Y IV emission from a high current density, cold cathode reflex discharge. The Y II to Y V emission is recorded in the 200-3000 A range using photometrically calibrated spectrometers, while the emission of trace aluminum ions serves for plasma diagnostics. The intensities of the Y IV 4d-5p and 5s7-5p transitions strongly increase relative to lines from Y II and Y III with increasing plasma current. The spectra studied here are obtained at a current density of 1.75 A/cm 2 . Experimental Y IV intensity ratios spanning several excited configurations are compared with collisional radiative predictions of the HULLAC atomic physics package. Good agreement is found for the measured and predicted ratios of 4p 5 5p to 4p 5 5s level populations per statistical weight. Finally, the response of the Kr-like system to a fast, transient excitation pulse is examined using the RADEX code. Large transient gains are predicted for several 5s-5p transitions in Kr-like Y IV. (orig.)

  18. A Sample of Quasars with Strong Nitrogen Emission Lines from the Sloan Digital Sky Survey

    DEFF Research Database (Denmark)

    Jiang, Linhua; Fan, Xiaohui; Vestergaard, Marianne

    2008-01-01

    We report on 293 quasars with strong NIV] lambda 1486 or NIII] lambda 1750 emission lines (rest-frame equivalent width > 3 \\AA) at 1.7......We report on 293 quasars with strong NIV] lambda 1486 or NIII] lambda 1750 emission lines (rest-frame equivalent width > 3 \\AA) at 1.7...

  19. Spontaneous electromagnetic emission from a strongly localized plasma flow.

    Science.gov (United States)

    Tejero, E M; Amatucci, W E; Ganguli, G; Cothran, C D; Crabtree, C; Thomas, E

    2011-05-06

    Laboratory observations of electromagnetic ion-cyclotron waves generated by a localized transverse dc electric field are reported. Experiments indicate that these waves result from a strong E×B flow inhomogeneity in a mildly collisional plasma with subcritical magnetic field-aligned current. The wave amplitude scales with the magnitude of the applied radial dc electric field. The electromagnetic signatures become stronger with increasing plasma β, and the radial extent of the power is larger than that of the electrostatic counterpart. Near-Earth space weather implications of the results are discussed.

  20. The CO/NOx emissions of swirled, strongly pulsed jet diffusion flames

    KAUST Repository

    Liao, Ying-Hao; Hermanson, James C.

    2014-01-01

    recirculation within the swirl-induced recirculation zone. Scaling relations, when taking into account the impact of air dilution over an injection cycle on the flame length, reveal a strong correlation between the CO emissions and the global residence time

  1. The climatology of low-latitude ionospheric densities and zonal drifts from IMAGE-FUV.

    Science.gov (United States)

    Immel, T. J.; Sagawa, E.; Frey, H. U.; Mende, S. B.; Patel, J.

    2004-12-01

    The IMAGE satellite was the first dedicated to magnetospheric imaging, but has also provided numerous images of the nightside ionosphere with its Far-Ultraviolet (FUV) spectrographic imager. Nightside emissions of O I at 135.6-nm originating away from the aurora are due to recombination of ionospheric O+, and vary in intensity with (O+)2. IMAGE-FUV, operating in a highly elliptical orbit with apogee at middle latitudes and >7 Re altitude, measures this emission globally with 100-km resolution. During each 14.5 hour orbit, IMAGE-FUV is able to monitor nightside ionospheric densities for up to 6-7 hours. Hundreds of low-latitude ionospheric bubbles, their development and drift speed, and a variety of other dynamical variations in brightness and morphology of the equatorial anomalies have been observed during this mission. Furthermore, the average global distribution of low-latitude ionospheric plasma densities can be determined in 3 days. Imaging data collected from February through June of 2002 are used to compile a dataset containing a variety of parameters (e.g., latitude and brightness of peak plasma density, zonal bubble drift speed) which can be drawn from for climatological studies. Recent results indicate that the average ground speed of low-latitude zonal plasma drifts vary with longitude by up to 50%, and that a periodic variation in ionospheric densities with longitude suggests the influence of a lower-thermospheric non-migrating tide with wave number = 4 on ionospheric densities. An excellent correlation between zonal drift speed and the magnetic storm index Dst is also found.

  2. Cycle 24 COS FUV Internal/External Wavelength Scale Monitor

    Science.gov (United States)

    Fischer, William J.

    2018-02-01

    We report on the monitoring of the COS FUV wavelength scale zero-points during Cycle 24 in program 14855. Select cenwaves were monitored for all FUV gratings at Lifetime Position 3. The target and cenwaves have remained the same since Cycle 21, with a change only to the target acquisition sequence. All measured offsets are within the error goals, although the G140L cenwaves show offsets at the short-wavelength end of segment A that are approaching the tolerance. This behavior will be closely monitored in subsequent iterations of the program.

  3. The CO/NOx emissions of swirled, strongly pulsed jet diffusion flames

    KAUST Repository

    Liao, Ying-Hao

    2014-05-28

    The CO and NOx exhaust emissions of swirled, strongly pulsed, turbulent jet diffusion flames were studied experimentally in a coflow swirl combustor. Measurements of emissions were performed on the combustor centerline using standard emission analyzers combined with an aspirated sampling probe located downstream of the visible flame tip. The highest levels of CO emissions are generally found for compact, isolated flame puffs, which is consistent with the quenching due to rapid dilution with excess air. The imposition of swirl generally results in a decrease in CO levels by up to a factor of 2.5, suggesting more rapid and compete fuel/air mixing by imposing swirl in the coflow stream. The levels of NO emissions for most cases are generally below the steady-flame value. The NO levels become comparable to the steady-flame value for sufficiently short jet-off times. The swirled coflow air can, in some cases, increase the NO emissions due to a longer combustion residence time due to the flow recirculation within the swirl-induced recirculation zone. Scaling relations, when taking into account the impact of air dilution over an injection cycle on the flame length, reveal a strong correlation between the CO emissions and the global residence time. However, the NO emissions do not successfully correlate with the global residence time. For some specific cases, a compact flame with a simultaneous decrease in both CO and NO emissions compared to the steady flames was observed. © Copyright © Taylor & Francis Group, LLC.

  4. Second COS FUV Lifetime Position: Verification of FUV Bright Object Aperture (BOA) Operations (FCAL4)

    Science.gov (United States)

    Debes, John H.

    2013-05-01

    As part of the calibration of the second lifetime position on the Cosmic Origins Spectrograph (COS) far-ultraviolet (FUV) detectors, observations of the external target, G191-B2B, were obtained with the G130M, G160M, and G140L gratings in combi- nation with the Bright Object Aperture. The observations were designed to verify the performance of these spectroscopic modes by reproducing similar observations taken during the SM4 Servicing Mission Observatory Verification (SMOV) of COS. These observations allowed for a detailed determination of the spatial location and profile of the spectra from the three gratings, as well as a determination of the spectral resolution of the G130M grating prior to and after the lifetime move. In general, the negligi- ble differences which exist between the two lifetime positions can be attributed to slight differences in the optical path. In particular, the spectral resolution appears to be slightly improved. The stability of the absolute and relative flux calibration was investigated for G130M as well using STIS echelle data of G191-B2B. We determine that the COS ab- solute flux calibration with the BOA is accurate to 10%, and flux calibrated data are reproducible at the 1-2% level since SMOV.

  5. Strongly emissive plasma-facing material under space-charge limited regime: Application to emissive probes

    Czech Academy of Sciences Publication Activity Database

    Cavalier, Jordan; Lemoine, N.; Bousselin, G.; Plihon, N.; Ledig, J.

    2017-01-01

    Roč. 24, č. 1 (2017), č. článku 013506. ISSN 1070-664X Institutional support: RVO:61389021 Keywords : plasma * tokamak * emissive probes Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.115, year: 2016 http://dx.doi.org/10.1063/1.4973557

  6. Molecular diagnostics of FUV and accretion-related heating in protoplanetary disks

    Science.gov (United States)

    Adamkovics, Mate; Najita, Joan R.

    2017-10-01

    Emission lines from the terrestrial planet forming regions of disks are diagnostic of both the physical processes that heat the gas and the chemistry that determines the inventory of nebular material available during the epoch of planet formation. Interpreting emission spectra is informed by models of radiative, thermal, physical, and chemical processes, such as: (i) the radiation transfer of X-rays and FUV --- both continuum and Ly-alpha, (ii) direct and indirect heating processes such as the photoelectric effect and photochemical heating, (iii) heating related to turbulent processes and viscous dissipation, and (iv) gas phase chemical reaction kinetics. Many of these processes depend on a the spatial distribution of dust grains and their properties, which temporally evolve during the lifetime of the disk and the formation of planets. Studies of disks atmospheres often predict a layered structure of hot (a few thousand K) atomic gas overlying warm (a few hundred K) molecular gas, which is generally consistent with the isothermal slab emission models that are used to interpret emission spectra. However, detailed comparison between observed spectra and models (e.g., comparing the total columns and the radial extent of warm emitting species) is rare.We present results including the implementation of Ly-alpha scattering, which is an important part of the photochemical heating and FUV heating radiation budget. By including these processes we find a new component of the disk atmosphere; hot molecular gas at ~2000K within radial distances of ~0.5AU, which is consistent with observations of UV-fluorescent H2 emission (Ádámkovics, Najita & Glassgold, 2016). Constraining the most optimistic contribution of radiative heating mechanisms via X-rays and FUV together with a favorable comparison to observations, allows us to explore and evaluate additional heating mechanisms. We find that the total columns of warm (90-400K) emitting molecules such as CO, arising directly below

  7. Existence of a virtual cathode close to a strongly electron emissive wall in low density plasmas

    International Nuclear Information System (INIS)

    Tierno, S. P.; Donoso, J. M.; Domenech-Garret, J. L.; Conde, L.

    2016-01-01

    The interaction between an electron emissive wall, electrically biased in a plasma, is revisited through a simple fluid model. We search for realistic conditions of the existence of a non-monotonic plasma potential profile with a virtual cathode as it is observed in several experiments. We mainly focus our attention on thermionic emission related to the operation of emissive probes for plasma diagnostics, although most conclusions also apply to other electron emission processes. An extended Bohm criterion is derived involving the ratio between the two different electron densities at the potential minimum and at the background plasma. The model allows a phase-diagram analysis, which confirms the existence of the non-monotonic potential profiles with a virtual cathode. This analysis shows that the formation of the potential well critically depends on the emitted electron current and on the velocity at the sheath edge of cold ions flowing from the bulk plasma. As a consequence, a threshold value of the governing parameter is required, in accordance to the physical nature of the electron emission process. The latter is a threshold wall temperature in the case of thermionic electrons. Experimental evidence supports our numerical calculations of this threshold temperature. Besides this, the potential well becomes deeper with increasing electron emission, retaining a fraction of the released current which limits the extent of the bulk plasma perturbation. This noninvasive property would explain the reliable measurements of plasma potential by using the floating potential method of emissive probes operating in the so-called strong emission regime

  8. Existence of a virtual cathode close to a strongly electron emissive wall in low density plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Tierno, S. P., E-mail: sp.tierno@upm.es; Donoso, J. M.; Domenech-Garret, J. L.; Conde, L. [Department of Applied Physics, E.T.S.I. Aeronáutica y del Espacio. Universidad Politécnica de Madrid, 28040 Madrid (Spain)

    2016-01-15

    The interaction between an electron emissive wall, electrically biased in a plasma, is revisited through a simple fluid model. We search for realistic conditions of the existence of a non-monotonic plasma potential profile with a virtual cathode as it is observed in several experiments. We mainly focus our attention on thermionic emission related to the operation of emissive probes for plasma diagnostics, although most conclusions also apply to other electron emission processes. An extended Bohm criterion is derived involving the ratio between the two different electron densities at the potential minimum and at the background plasma. The model allows a phase-diagram analysis, which confirms the existence of the non-monotonic potential profiles with a virtual cathode. This analysis shows that the formation of the potential well critically depends on the emitted electron current and on the velocity at the sheath edge of cold ions flowing from the bulk plasma. As a consequence, a threshold value of the governing parameter is required, in accordance to the physical nature of the electron emission process. The latter is a threshold wall temperature in the case of thermionic electrons. Experimental evidence supports our numerical calculations of this threshold temperature. Besides this, the potential well becomes deeper with increasing electron emission, retaining a fraction of the released current which limits the extent of the bulk plasma perturbation. This noninvasive property would explain the reliable measurements of plasma potential by using the floating potential method of emissive probes operating in the so-called strong emission regime.

  9. Existence of a virtual cathode close to a strongly electron emissive wall in low density plasmas

    Science.gov (United States)

    Tierno, S. P.; Donoso, J. M.; Domenech-Garret, J. L.; Conde, L.

    2016-01-01

    The interaction between an electron emissive wall, electrically biased in a plasma, is revisited through a simple fluid model. We search for realistic conditions of the existence of a non-monotonic plasma potential profile with a virtual cathode as it is observed in several experiments. We mainly focus our attention on thermionic emission related to the operation of emissive probes for plasma diagnostics, although most conclusions also apply to other electron emission processes. An extended Bohm criterion is derived involving the ratio between the two different electron densities at the potential minimum and at the background plasma. The model allows a phase-diagram analysis, which confirms the existence of the non-monotonic potential profiles with a virtual cathode. This analysis shows that the formation of the potential well critically depends on the emitted electron current and on the velocity at the sheath edge of cold ions flowing from the bulk plasma. As a consequence, a threshold value of the governing parameter is required, in accordance to the physical nature of the electron emission process. The latter is a threshold wall temperature in the case of thermionic electrons. Experimental evidence supports our numerical calculations of this threshold temperature. Besides this, the potential well becomes deeper with increasing electron emission, retaining a fraction of the released current which limits the extent of the bulk plasma perturbation. This noninvasive property would explain the reliable measurements of plasma potential by using the floating potential method of emissive probes operating in the so-called strong emission regime.

  10. Enhanced Fluoride Over-Coated Al Mirrors for FUV Astronomy

    Science.gov (United States)

    Quijada, Manuel A.; DelHoyo, Javier; Rice, Steve; Threat, Felix

    2014-01-01

    Astronomical observations in the Far Ultraviolet (FUV) spectral region are some of the more challenging due to the very distant and faint objects that are typically searched for in cosmic origin studies such as origin of large scale structure, the formation, evolution, and age of galaxies and the origin of stellar and planetary systems. These challenges are driving the need to improve the performance of optical coatings over a wide spectral range that would increase reflectance in mirrors and reduced absorption in dielectric filters used in optical telescope for FUV observations. This paper will present recent advances in reflectance performance for Al+MgF2 mirrors optimized for Lyman-alpha wavelength by performing the deposition of the MgF2 overcoat at elevated substrate temperatures. We will also present optical characterization of little studied rare-earth fluorides such as GdF3 and LuF3 that exhibit low-absorption over a wide wavelength range and could therefore be used as high refractive index alternatives for dielectric coatings at FUV wavelengths.

  11. Strong blue emission from ZnO nanocrystals synthesized in acetone-based solvent

    International Nuclear Information System (INIS)

    Efafi, B.; Majles Ara, M.H.; Mousavi, S.S.

    2016-01-01

    In this research, ZnO nanocrystals were synthesized by an improved sol–gel method. UV–vis, FTIR and photoluminescence spectra of the ZnO solution synthesized by this route indicated different properties compared to the other preparation methods. It was observed from FTIR that the sol (prepared using acetone) with the low concentration contains a noticeable amount of the Zn–O bond. The PL spectrum with a strong blue emission confirmed that these nanocrystals are good candidate for use in applications where a monochromatic emission is required. To the best of our knowledge, monochromatic emission ZnO devices have been fabricated through high technology instruments but this paper introduces a simple method for preparation of ZnO with the high intensity blue peak. The size and morphology of ZnO nanocrystals have been studied using FESEM. The nanocrystal size was estimated about 70 nm which was in good agreement with XRD data. - Highlights: • Preparation of ZnO nanocrystals through a novel method by the use of acetone as the solvent. • Observation of the strong blue emission peak from the ZnO prepared solution. • Reduction of green emission in the synthesized sample compared to the other methods of preparation.

  12. Strong blue emission from ZnO nanocrystals synthesized in acetone-based solvent

    Energy Technology Data Exchange (ETDEWEB)

    Efafi, B. [NanoPhotonics Lab., Physics Department, Kharazmi University, Tehran (Iran, Islamic Republic of); Departments of Physics, Iran University of Science & Technology, Tehran (Iran, Islamic Republic of); Majles Ara, M.H., E-mail: majlesara@gmail.com [NanoPhotonics Lab., Physics Department, Kharazmi University, Tehran (Iran, Islamic Republic of); Mousavi, S.S. [NanoPhotonics Lab., Physics Department, Kharazmi University, Tehran (Iran, Islamic Republic of)

    2016-10-15

    In this research, ZnO nanocrystals were synthesized by an improved sol–gel method. UV–vis, FTIR and photoluminescence spectra of the ZnO solution synthesized by this route indicated different properties compared to the other preparation methods. It was observed from FTIR that the sol (prepared using acetone) with the low concentration contains a noticeable amount of the Zn–O bond. The PL spectrum with a strong blue emission confirmed that these nanocrystals are good candidate for use in applications where a monochromatic emission is required. To the best of our knowledge, monochromatic emission ZnO devices have been fabricated through high technology instruments but this paper introduces a simple method for preparation of ZnO with the high intensity blue peak. The size and morphology of ZnO nanocrystals have been studied using FESEM. The nanocrystal size was estimated about 70 nm which was in good agreement with XRD data. - Highlights: • Preparation of ZnO nanocrystals through a novel method by the use of acetone as the solvent. • Observation of the strong blue emission peak from the ZnO prepared solution. • Reduction of green emission in the synthesized sample compared to the other methods of preparation.

  13. Turbulent structure and emissions of strongly-pulsed jet diffusion flames

    Science.gov (United States)

    Fregeau, Mathieu

    This current research project studied the turbulent flame structure, the fuel/air mixing, the combustion characteristics of a nonpremixed pulsed (unsteady) and unpulsed (steady) flame configuration for both normal- and microgravity conditions, as well as the flame emissions in normal gravity. The unsteady flames were fully-modulated, with the fuel flow completely shut off between injection pulses using an externally controlled valve, resulting in the generation of compact puff-like flame structures. Conducting experiments in normal and microgravity environments enabled separate control over the relevant Richardson and Reynolds numbers to clarify the influence of buoyancy on the flame behavior, mixing, and structure. Experiments were performed in normal gravity in the laboratory at the University of Washington and in microgravity using the NASA GRC 2.2-second Drop Tower facility. High-speed imaging, as well as temperature and emissions probes were used to determine the large-scale structure dynamics, the details of the flame structure and oxidizer entrainment, the combustion temperatures, and the exhaust emissions of the pulsed and steady flames. Of particular interest was the impact of changes in flame structure due to pulsing on the combustion characteristics of this system. The turbulent flame puff celerity (i.e., the bulk velocity of the puffs) was strongly impacted by the jet-off time, increasing markedly as the time between pulses was decreased, which caused the degree of puff interaction to increase and the strongly-pulsed flame to more closely resemble a steady flame. This increase occurred for all values of injection time as well as for constant fuelling rate and in both the presence and absence of buoyancy. The removal of positive buoyancy in microgravity resulted in a decrease in the flame puff celerity in all cases, amounting to as much as 40%, for both constant jet injection velocity and constant fuelling rate. The mean flame length of the strongly

  14. Polarized X-Ray Emission from Magnetized Neutron Stars: Signature of Strong-Field Vacuum Polarization

    Science.gov (United States)

    Lai, Dong; Ho, Wynn C.

    2003-08-01

    In the atmospheric plasma of a strongly magnetized neutron star, vacuum polarization can induce a Mikheyev-Smirnov-Wolfenstein type resonance across which an x-ray photon may (depending on its energy) convert from one mode into the other, with significant changes in opacities and polarizations. We show that this vacuum resonance effect gives rise to a unique energy-dependent polarization signature in the surface emission from neutron stars. The detection of polarized x rays from neutron stars can provide a direct probe of strong-field quantum electrodynamics and constrain the neutron star magnetic field and geometry.

  15. Polarized x-ray emission from magnetized neutron stars: signature of strong-field vacuum polarization.

    Science.gov (United States)

    Lai, Dong; Ho, Wynn C G

    2003-08-15

    In the atmospheric plasma of a strongly magnetized neutron star, vacuum polarization can induce a Mikheyev-Smirnov-Wolfenstein type resonance across which an x-ray photon may (depending on its energy) convert from one mode into the other, with significant changes in opacities and polarizations. We show that this vacuum resonance effect gives rise to a unique energy-dependent polarization signature in the surface emission from neutron stars. The detection of polarized x rays from neutron stars can provide a direct probe of strong-field quantum electrodynamics and constrain the neutron star magnetic field and geometry.

  16. The strong 3.3 micron emission line in Wolf-Rayet stars

    International Nuclear Information System (INIS)

    Williams, P.M.

    1982-01-01

    A number of Wolf-Rayet stars have been found to show in their spectra a strong emission feature at 3.28 μm, the wavelength of the 'unidentified' feature observed in some nebular spectra. From comparison of the strength of this line from stars of different spectral type and excitation, it is identified with the CIV (11-10) transition group and shown not to be connected with the circumstellar dust associated with some Wolf-Rayet stars. (author)

  17. Strong water absorption in the dayside emission spectrum of the planet HD 189733b.

    Science.gov (United States)

    Grillmair, Carl J; Burrows, Adam; Charbonneau, David; Armus, Lee; Stauffer, John; Meadows, Victoria; van Cleve, Jeffrey; von Braun, Kaspar; Levine, Deborah

    2008-12-11

    Recent observations of the extrasolar planet HD 189733b did not reveal the presence of water in the emission spectrum of the planet. Yet models of such 'hot-Jupiter' planets predict an abundance of atmospheric water vapour. Validating and constraining these models is crucial to understanding the physics and chemistry of planetary atmospheres in extreme environments. Indications of the presence of water in the atmosphere of HD 189733b have recently been found in transmission spectra, where the planet's atmosphere selectively absorbs the light of the parent star, and in broadband photometry. Here we report the detection of strong water absorption in a high-signal-to-noise, mid-infrared emission spectrum of the planet itself. We find both a strong downturn in the flux ratio below 10 microm and discrete spectral features that are characteristic of strong absorption by water vapour. The differences between these and previous observations are significant and admit the possibility that predicted planetary-scale dynamical weather structures may alter the emission spectrum over time. Models that match the observed spectrum and the broadband photometry suggest that heat redistribution from the dayside to the nightside is weak. Reconciling this with the high nightside temperature will require a better understanding of atmospheric circulation or possible additional energy sources.

  18. Strong geologic methane emissions from discontinuous terrestrial permafrost in the Mackenzie Delta, Canada.

    Science.gov (United States)

    Kohnert, Katrin; Serafimovich, Andrei; Metzger, Stefan; Hartmann, Jörg; Sachs, Torsten

    2017-07-19

    Arctic permafrost caps vast amounts of old, geologic methane (CH 4 ) in subsurface reservoirs. Thawing permafrost opens pathways for this CH 4 to migrate to the surface. However, the occurrence of geologic emissions and their contribution to the CH 4 budget in addition to recent, biogenic CH 4 is uncertain. Here we present a high-resolution (100 m × 100 m) regional (10,000 km²) CH 4 flux map of the Mackenzie Delta, Canada, based on airborne CH 4 flux data from July 2012 and 2013. We identify strong, likely geologic emissions solely where the permafrost is discontinuous. These peaks are 13 times larger than typical biogenic emissions. Whereas microbial CH 4 production largely depends on recent air and soil temperature, geologic CH 4 was produced over millions of years and can be released year-round provided open pathways exist. Therefore, even though they only occur on about 1% of the area, geologic hotspots contribute 17% to the annual CH 4 emission estimate of our study area. We suggest that this share may increase if ongoing permafrost thaw opens new pathways. We conclude that, due to permafrost thaw, hydrocarbon-rich areas, prevalent in the Arctic, may see increased emission of geologic CH 4 in the future, in addition to enhanced microbial CH 4 production.

  19. Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions

    Science.gov (United States)

    Isaksen, Ivar S.A.; Gauss, Michael; Myhre, Gunnar; Walter Anthony, Katey M.; Ruppel, Carolyn

    2011-01-01

    The magnitude and feedbacks of future methane release from the Arctic region are unknown. Despite limited documentation of potential future releases associated with thawing permafrost and degassing methane hydrates, the large potential for future methane releases calls for improved understanding of the interaction of a changing climate with processes in the Arctic and chemical feedbacks in the atmosphere. Here we apply a “state of the art” atmospheric chemistry transport model to show that large emissions of CH4 would likely have an unexpectedly large impact on the chemical composition of the atmosphere and on radiative forcing (RF). The indirect contribution to RF of additional methane emission is particularly important. It is shown that if global methane emissions were to increase by factors of 2.5 and 5.2 above current emissions, the indirect contributions to RF would be about 250% and 400%, respectively, of the RF that can be attributed to directly emitted methane alone. Assuming several hypothetical scenarios of CH4 release associated with permafrost thaw, shallow marine hydrate degassing, and submarine landslides, we find a strong positive feedback on RF through atmospheric chemistry. In particular, the impact of CH4 is enhanced through increase of its lifetime, and of atmospheric abundances of ozone, stratospheric water vapor, and CO2 as a result of atmospheric chemical processes. Despite uncertainties in emission scenarios, our results provide a better understanding of the feedbacks in the atmospheric chemistry that would amplify climate warming.

  20. A sol-gel method for preparing ZnO quantum dots with strong blue emission

    International Nuclear Information System (INIS)

    Chen Zhong; Li Xiaoxia; Du Guoping; Chen Nan; Suen, Andy Y.M.

    2011-01-01

    ZnO quantum dots (QDs) with strong blue emission have been successfully synthesized by sol-gel method, and their crystal structures, sizes, and photoluminescence properties were characterized by X-ray diffractometer, scanning electron microscope, and ultraviolet-visible spectroscopy. It has been found that ZnO QDs had a hexagonal wurtzite crystal structure, and their average diameter was about 16.0-32.2 nm. Both the reaction time and temperature were found to have a strong influence on the average size and photoluminescence properties of ZnO QDs. Longer reaction time and higher reaction temperature resulted in larger average size for ZnO QDs. It has been shown that at reaction temperature 60 deg. C the emission intensity for ZnO QDs increased first with reaction time before 7 h and then decreased after 7 h. For the same reaction time 7 h, ZnO QDs synthesized at 60 deg. C showed the strongest emission intensity. It was found that annealing in nitrogen, vacuum, and air all resulted in an increase of the size of ZnO QDs and a reduction in their photoluminescence. The dependence of the size and properties of ZnO QDs on the reaction parameters as well as the annealing conditions has been discussed. - Highlights: → ZnO quantum dots (QDs) with strong blue emission were prepared by sol-gel method. → ZnO QDs had a pure spectral blue with the chromaticity coordinates (0.166, 0.215). → Optimal reaction time and temperature were 7 h and 60 deg. C, respectively.

  1. Directed emission of CdSe nanoplatelets originating from strongly anisotropic 2D electronic structure

    Science.gov (United States)

    Scott, Riccardo; Heckmann, Jan; Prudnikau, Anatol V.; Antanovich, Artsiom; Mikhailov, Aleksandr; Owschimikow, Nina; Artemyev, Mikhail; Climente, Juan I.; Woggon, Ulrike; Grosse, Nicolai B.; Achtstein, Alexander W.

    2017-12-01

    Intrinsically directional light emitters are potentially important for applications in photonics including lasing and energy-efficient display technology. Here, we propose a new route to overcome intrinsic efficiency limitations in light-emitting devices by studying a CdSe nanoplatelets monolayer that exhibits strongly anisotropic, directed photoluminescence. Analysis of the two-dimensional k-space distribution reveals the underlying internal transition dipole distribution. The observed directed emission is related to the anisotropy of the electronic Bloch states governing the exciton transition dipole moment and forming a bright plane. The strongly directed emission perpendicular to the platelet is further enhanced by the optical local density of states and local fields. In contrast to the emission directionality, the off-resonant absorption into the energetically higher 2D-continuum of states is isotropic. These contrasting optical properties make the oriented CdSe nanoplatelets, or superstructures of parallel-oriented platelets, an interesting and potentially useful class of semiconductor-based emitters.

  2. Strong white light emission from a processed porous silicon and its photoluminescence mechanism

    International Nuclear Information System (INIS)

    Karacali, T.; Cicek, K.

    2011-01-01

    We have prepared various porous silicon (PS) structures with different surface conditions (any combination of oxidation, carbonization as well as thermal annealing) to increase the intensity of photoluminescence (PL) spectrum in the visible range. Strong white light (similar to day-light) emission was achieved by carrying out thermal annealing at 1100 deg. C after surface modification with 1-decene of anodic oxidized PS structures. Temperature-dependent PL measurements were first performed by gradually increasing the sample temperature from 10 to 300 K inside a cryostat. Then, we analyzed the measured spectrum of all prepared samples. After the analysis, we note that throughout entire measured spectrum, only two main peaks corresponding to blue and green-orange emission lines (which can be interpreted by quantum size effect and/or configuration coordinate model) were seem to be predominant for all temperature range. To further reveal and analysis these peaks, finally, measured data were inputted into the formula of activation energy of thermal excitation. We found that activation energies of blue and green-orange lines were approximately 49.3 and 44.6 meV, respectively. - Highlights: →Light emitting devices based on silicon technology are of great interest in illumination and display applications. → We have achieved strong white light (similar to day-light) emission from porous silicon. → The most important impact of carbonization on porous silicon and post annealing is the enhancement of room temperature luminescence.

  3. Laser based imaging of time depending microscopic scenes with strong light emission

    Science.gov (United States)

    Hahlweg, Cornelius; Wilhelm, Eugen; Rothe, Hendrik

    2011-10-01

    Investigating volume scatterometry methods based on short range LIDAR devices for non-static objects we achieved interesting results aside the intended micro-LIDAR: the high speed camera recording of the illuminated scene of an exploding wire -intended for Doppler LIDAR tests - delivered a very effective method of observing details of objects with extremely strong light emission. As a side effect a schlieren movie is gathered without any special effort. The fact that microscopic features of short time processes with high emission and material flow might be imaged without endangering valuable equipment makes this technique at least as interesting as the intended one. So we decided to present our results - including latest video and photo material - instead of a more theoretical paper on our progress concerning the primary goal.

  4. Relativistic quantum dynamics in strong fields: Photon emission from heavy, few-electron ions

    International Nuclear Information System (INIS)

    Fritzsche, S.; Stoehlker, T.

    2005-03-01

    Recent progress in the study of the photon emission from highly-charged heavy ions is reviewed. These investigations show that high-Z ions provide a unique tool for improving the understanding of the electron-electron and electron-photon interaction in the presence of strong fields. Apart from the bound-state transitions, which are accurately described in the framework of quantum electrodynamics, much information has been obtained also from the radiative capture of (quasi-) free electrons by high-Z ions. Many features in the observed spectra hereby confirm the inherently relativistic behavior of even the simplest compound quantum systems in nature. (orig.)

  5. The first detection of neutral hydrogen in emission in a strong spiral lens

    Science.gov (United States)

    Lipnicky, Andrew; Chakrabarti, Sukanya; Wright, Melvyn C. H.; Blitz, Leo; Heiles, Carl; Cotton, William; Frayer, David; Blandford, Roger; Shu, Yiping; Bolton, Adam S.

    2018-05-01

    We report H I observations of eight spiral galaxies that are strongly lensing background sources. Our targets were selected from the Sloan WFC (Wide Field Camera) Edge-on Late-type Lens Survey (SWELLS) using the Arecibo, Karl G. Jansky Very Large Array, and Green Bank telescopes. We securely detect J1703+2451 at z = 0.063 with a signal-to-noise ratio of 6.7 and W50 = 79 ± 13 km s-1, obtaining the first detection of H I emission in a strong spiral lens. We measure a mass of M_{H I} = (1.77± 0.06^{+0.35}_{-0.75})× 10^9 M_{⊙} for this source. We find that this lens is a normal spiral, with observable properties that are fairly typical of spiral galaxies. For three other sources, we did not secure a detection; however, we are able to place strong constraints on the H I masses of those galaxies. The observations for four of our sources were rendered unusable due to strong radio frequency interference.

  6. STRONG FIELD EFFECTS ON EMISSION LINE PROFILES: KERR BLACK HOLES AND WARPED ACCRETION DISKS

    International Nuclear Information System (INIS)

    Wang Yan; Li Xiangdong

    2012-01-01

    If an accretion disk around a black hole is illuminated by hard X-rays from non-thermal coronae, fluorescent iron lines will be emitted from the inner region of the accretion disk. The emission line profiles will show a variety of strong field effects, which may be used as a probe of the spin parameter of the black hole and the structure of the accretion disk. In this paper, we generalize the previous relativistic line profile models by including both the black hole spinning effects and the non-axisymmetries of warped accretion disks. Our results show different features from the conventional calculations for either a flat disk around a Kerr black hole or a warped disk around a Schwarzschild black hole by presenting, at the same time, multiple peaks, rather long red tails, and time variations of line profiles with the precession of the disk. We show disk images as seen by a distant observer, which are distorted by the strong gravity. Although we are primarily concerned with the iron K-shell lines in this paper, the calculation is general and is valid for any emission lines produced from a warped accretion disk around a black hole.

  7. Surface emission of InxGa1-xN epilayers under strong optical excitation

    International Nuclear Information System (INIS)

    Jiang, H.X.; Lin, J.Y.; Khan, M.A.; Chen, Q.; Yang, J.W.

    1997-01-01

    Effects of strong optical excitation on the properties of surface emission from an InGaN/GaN heterostructure grown by metal-organic chemical-vapor deposition have been investigated. An intriguing feature observed was that as the excitation intensity increased the surface emission spectrum evolved abruptly from a single dominating band to two dominating bands at a critical intensity. This phenomenon has a sharp phase transition or a switching character and can be accounted for by (i) the formation of an electron endash hole plasma state in the InGaN vertical cavity under strong optical excitation, (ii) the photoreflectance effect (variation of index of refraction with excitation intensity), and (c) the Fabry endash Pacute erot interference effect in the InGaN vertical cavity. These findings are expected to have impact on the design of the laser structures, in particular on the design of the vertical-cavity surface-emitting laser diodes based on III-nitride wide-band-gap semiconductors. copyright 1997 American Institute of Physics

  8. Engineering light emission of two-dimensional materials in both the weak and strong coupling regimes

    Science.gov (United States)

    Brotons-Gisbert, Mauro; Martínez-Pastor, Juan P.; Ballesteros, Guillem C.; Gerardot, Brian D.; Sánchez-Royo, Juan F.

    2018-01-01

    Two-dimensional (2D) materials have promising applications in optoelectronics, photonics, and quantum technologies. However, their intrinsically low light absorption limits their performance, and potential devices must be accurately engineered for optimal operation. Here, we apply a transfer matrix-based source-term method to optimize light absorption and emission in 2D materials and related devices in weak and strong coupling regimes. The implemented analytical model accurately accounts for experimental results reported for representative 2D materials such as graphene and MoS2. The model has been extended to propose structures to optimize light emission by exciton recombination in MoS2 single layers, light extraction from arbitrarily oriented dipole monolayers, and single-photon emission in 2D materials. Also, it has been successfully applied to retrieve exciton-cavity interaction parameters from MoS2 microcavity experiments. The present model appears as a powerful and versatile tool for the design of new optoelectronic devices based on 2D semiconductors such as quantum light sources and polariton lasers.

  9. Strongly lensed neutral hydrogen emission: detection predictions with current and future radio interferometers

    Science.gov (United States)

    Deane, R. P.; Obreschkow, D.; Heywood, I.

    2015-09-01

    Strong gravitational lensing provides some of the deepest views of the Universe, enabling studies of high-redshift galaxies only possible with next-generation facilities without the lensing phenomenon. To date, 21-cm radio emission from neutral hydrogen has only been detected directly out to z ˜ 0.2, limited by the sensitivity and instantaneous bandwidth of current radio telescopes. We discuss how current and future radio interferometers such as the Square Kilometre Array (SKA) will detect lensed H I emission in individual galaxies at high redshift. Our calculations rely on a semi-analytic galaxy simulation with realistic H I discs (by size, density profile and rotation), in a cosmological context, combined with general relativistic ray tracing. Wide-field, blind H I surveys with the SKA are predicted to be efficient at discovering lensed H I systems, increasingly so at z ≳ 2. This will be enabled by the combination of the magnification boosts, the steepness of the H I luminosity function at the high-mass end, and the fact that the H I spectral line is relatively isolated in frequency. These surveys will simultaneously provide a new technique for foreground lens selection and yield the highest redshift H I emission detections. More near term (and existing) cm-wave facilities will push the high-redshift H I envelope through targeted surveys of known lenses.

  10. Flame Structure and Emissions of Strongly-Pulsed Turbulent Diffusion Flames with Swirl

    Science.gov (United States)

    Liao, Ying-Hao

    This work studies the turbulent flame structure, the reaction-zone structure and the exhaust emissions of strongly-pulsed, non-premixed flames with co-flow swirl. The fuel injection is controlled by strongly-pulsing the fuel flow by a fast-response solenoid valve such that the fuel flow is completely shut off between pulses. This control strategy allows the fuel injection to be controlled over a wide range of operating conditions, allowing the flame structure to range from isolated fully-modulated puffs to interacting puffs to steady flames. The swirl level is controlled by varying the ratio of the volumetric flow rate of the tangential air to that of the axial air. For strongly-pulsed flames, both with and without swirl, the flame geometry is strongly impacted by the injection time. Flames appear to exhibit compact, puff-like structures for short injection times, while elongated flames, similar in behaviors to steady flames, occur for long injection times. The flames with swirl are found to be shorter for the same fuel injection conditions. The separation/interaction level between flame puffs in these flames is essentially governed by the jet-off time. The separation between flame puffs decreases as swirl is imposed, consistent with the decrease in flame puff celerity due to swirl. The decreased flame length and flame puff celerity are consistent with an increased rate of air entrainment due to swirl. The highest levels of CO emissions are generally found for compact, isolated flame puffs, consistent with the rapid quenching due to rapid dilution with excess air. The imposition of swirl generally results in a decrease in CO levels, suggesting more rapid and complete fuel/air mixing by imposing swirl in the co-flow stream. The levels of NO emissions for most cases are generally below the steady-flame value. The NO levels become comparable to the steady-flame value for sufficiently short jet-off time. The swirled co-flow air can, in some cases, increase the NO

  11. Highly stable colloidal TiO2 nanocrystals with strong violet-blue emission

    International Nuclear Information System (INIS)

    Ghamsari, Morteza Sasani; Gaeeni, Mohammad Reza; Han, Wooje; Park, Hyung-Ho

    2016-01-01

    Improved sol–gel method has been applied to prepare highly stable colloidal TiO 2 nanocrystals. The synthesized titania nanocrystals exhibit strong emission in the violet-blue wavelength region. Very long evolution time was obtained by preventing the sol to gel conversion with reflux process. FTIR, XRD, UV–vis absorption, photoluminescence and high resolution transmission electron microscope (HRTEM) were used to study the optical properties, crystalline phase, morphology, shape and size of prepared TiO 2 colloidal nanocrystals. HRTEM showed that the diameter of TiO 2 colloidal nanocrystals is about 5 nm. Although the PL spectra show similar spectral features upon excitation wavelengths at 280, 300 and 350 nm, but their emission intensities are significantly different from each other. Photoluminescence quantum yield for TiO 2 colloidal nanocrystals is estimated to be 49% with 280 nm excitation wavelength which is in agreement and better than reported before. Obtained results confirm that the prepared colloidal TiO 2 sample has enough potential for optoelectronics applications.

  12. Highly stable colloidal TiO{sub 2} nanocrystals with strong violet-blue emission

    Energy Technology Data Exchange (ETDEWEB)

    Ghamsari, Morteza Sasani, E-mail: msghamsari@yahoo.com [Laser & Optics Research School, NSTRI, 11155-3486 Tehran (Iran, Islamic Republic of); Gaeeni, Mohammad Reza [Laser & Optics Research School, NSTRI, 11155-3486 Tehran (Iran, Islamic Republic of); Han, Wooje; Park, Hyung-Ho [Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

    2016-10-15

    Improved sol–gel method has been applied to prepare highly stable colloidal TiO{sub 2} nanocrystals. The synthesized titania nanocrystals exhibit strong emission in the violet-blue wavelength region. Very long evolution time was obtained by preventing the sol to gel conversion with reflux process. FTIR, XRD, UV–vis absorption, photoluminescence and high resolution transmission electron microscope (HRTEM) were used to study the optical properties, crystalline phase, morphology, shape and size of prepared TiO{sub 2} colloidal nanocrystals. HRTEM showed that the diameter of TiO{sub 2} colloidal nanocrystals is about 5 nm. Although the PL spectra show similar spectral features upon excitation wavelengths at 280, 300 and 350 nm, but their emission intensities are significantly different from each other. Photoluminescence quantum yield for TiO{sub 2} colloidal nanocrystals is estimated to be 49% with 280 nm excitation wavelength which is in agreement and better than reported before. Obtained results confirm that the prepared colloidal TiO{sub 2} sample has enough potential for optoelectronics applications.

  13. Spontaneous emission spectra and quantum light-matter interactions from a strongly coupled quantum dot metal-nanoparticle system

    DEFF Research Database (Denmark)

    Van Vlack, C.; Kristensen, Philip Trøst; Hughes, S.

    2012-01-01

    the dot to the detector, we demonstrate that the strong-coupling regime should be observable in the far-field spontaneous emission spectrum, even at room temperature. The vacuum-induced emission spectra show that the usual vacuum Rabi doublet becomes a rich spectral triplet or quartet with two of the four...

  14. Problems related to stimulated electromagnetic emissions, strong turbulence and ionospheric modification

    International Nuclear Information System (INIS)

    Goodman, S.

    1993-05-01

    Optical pumping of the ionospheric plasma by high-frequency radio waves produces a state of turbulence. Several consequences of the pumping are considered in this thesis. At reflection altitude the plasma is thought to be dominated by parametric instabilities and strong turbulence; these are both encapsulated in the so called Zakharov equations. The Zakharov equations are derived and generalised from kinetic theory. Limits of validity, corrections to the ion sound speed,effective ponderomotive force, nonlinear damping and other generalisation are included. As an example of the difference a kinetic approach makes, the threshold for parametric instabilities is seen to be lowered in a kinetic plasma. Mostly relevant to the upper hybrid layer is the recent discovery in the pumping experiments of stimulated electromagnetic emissions (SEE). In particular one feature of SEE which occurs around the cyclotron harmonics and depends on density striations is investigated. The observed frequency of emission, dependency on striations, time evolution and cutoff frequency below which the feature does not occur, are explained. Two theoretical approaches are taken. The first is a parametric three wave decay instability followed by a nonlinear mixing to produce SEE. Thresholds for the instability are well within experimental capacity. The second, less orthodox, approach, is a finite amplitude model. The finite amplitude model goes beyond the traditional parametric approach by being able to predict radiated power output. Miscellaneous aspects of a turbulent ionosphere are also examined. The dependency of the scattering cross section of a turbulent plasma upon higher order perturbations is considered. In a turbulent plasma, density gradients steeper than characteristic plasma scales may develop. The case of calculating the dielectric permittivity for a linear gradient of arbitrary steepness is considered

  15. SORCE SOLSTICE FUV Level 3 Solar Spectral Irradiance Daily Means V012

    Data.gov (United States)

    National Aeronautics and Space Administration — The SORCE SOLSTICE Far-UV Solar Spectral Irradiance (SSI) data product SOR3SOLFUVD is constructed using measurements from the SOLSTICE FUV instrument, which are...

  16. Very Strong TeV Emission as $\\gamma$-Ray Burst Afterglows

    CERN Document Server

    Totani, T

    1998-01-01

    Gamma-ray bursts (GRBs) and following afterglows are considered to be produced by dissipation of kinetic energy of a relativistic fireball and radiation process is widely believed as synchrotron radiation or inverse Compton scattering of electrons. We argue that the transfer of kinetic energy of ejecta into electrons may be inefficient process and hence the total energy released by a GRB event is much larger than that emitted in soft gamma-rays, by a factor of \\sim (m_p/m_e). We show that, in this case, very strong emission of TeV gamma-rays is possible due to synchrotron radiation of protons accelerated up to \\sim 10^{21} eV, which are trapped in the magnetic field of afterglow shock and radiate their energy on an observational time scale of \\sim day. This suggests a possibility that GRBs are most energetic in TeV range and such TeV gamma-rays may be detectable from GRBs even at cosmological distances, i.e., z gives a quantitative explanation for the famous long-duration GeV photons detected from GRB940217. ...

  17. Strong Photonic-Band-Gap Effect on the Spontaneous Emission in 3D Lead Halide Perovskite Photonic Crystals.

    Science.gov (United States)

    Zhou, Xue; Li, Mingzhu; Wang, Kang; Li, Huizeng; Li, Yanan; Li, Chang; Yan, Yongli; Zhao, Yongsheng; Song, Yanlin

    2018-03-25

    Stimulated emission in perovskite-embedded polymer opal structures is investigated. A polymer opal structure is filled with a perovskite, and perovskite photonic crystals are prepared. The spontaneous emission of the perovskite embedded in the polymer opal structures exhibits clear signatures of amplified spontaneous emission (ASE) via gain modulation. The difference in refractive-index contrast between the perovskite and the polymer opal is large enough for retaining photonic-crystals properties. The photonic band gap has a strong effect on the fluorescence emission intensity and lifetime. The stimulated emission spectrum exhibits a narrow ASE rather than a wide fluorescence peak in the thin film. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Quantification of Greenhouse Gas Emission Rates from strong Point Sources by Airborne IPDA-Lidar Measurements: Methodology and Experimental Results

    Science.gov (United States)

    Ehret, G.; Amediek, A.; Wirth, M.; Fix, A.; Kiemle, C.; Quatrevalet, M.

    2016-12-01

    We report on a new method and on the first demonstration to quantify emission rates from strong greenhouse gas (GHG) point sources using airborne Integrated Path Differential Absorption (IPDA) Lidar measurements. In order to build trust in the self-reported emission rates by countries, verification against independent monitoring systems is a prerequisite to check the reported budget. A significant fraction of the total anthropogenic emission of CO2 and CH4 originates from localized strong point sources of large energy production sites or landfills. Both are not monitored with sufficiently accuracy by the current observation system. There is a debate whether airborne remote sensing could fill in the gap to infer those emission rates from budgeting or from Gaussian plume inversion approaches, whereby measurements of the GHG column abundance beneath the aircraft can be used to constrain inverse models. In contrast to passive sensors, the use of an active instrument like CHARM-F for such emission verification measurements is new. CHARM-F is a new airborne IPDA-Lidar devised for the German research aircraft HALO for the simultaneous measurement of the column-integrated dry-air mixing ratio of CO2 and CH4 commonly denoted as XCO2 und XCH4, respectively. It has successfully been tested in a serious of flights over Central Europe to assess its performance under various reflectivity conditions and in a strongly varying topography like the Alps. The analysis of a methane plume measured in crosswind direction of a coal mine ventilation shaft revealed an instantaneous emission rate of 9.9 ± 1.7 kt CH4 yr-1. We discuss the methodology of our point source estimation approach and give an outlook on the CoMet field experiment scheduled in 2017 for the measurement of anthropogenic and natural GHG emissions by a combination of active and passive remote sensing instruments on research aircraft.

  19. COS2025: Extending the Lifetime of the FUV channel of the Cosmic Origins Spectrograph to 2025

    Science.gov (United States)

    Rafelski, Marc; De Rosa, Gisella; Fischer, William J.; Fix, Mees; Fox, Andrew; Indriolo, Nick; James, Bethan; Magness, Camellia; Oliveira, Cristina M.; Penton, Steven V.; Plesha, Rachel; Roman-Duval, Julia; Sahnow, David J.; Sankrit, Ravi; Snyder, Elaine M.; Taylor, Joanna M.; White, James

    2018-01-01

    The Hubble Space Telescope's Cosmic Origins Spectrograph (COS) Far-Ultraviolet (FUV) microchannel plate detector's efficiency at converting incoming photons into detectable events decreases with usage. This depletion of the detector's gain (i.e. gain sag) results in unusable regions of the COS/FUV detector. In order to mitigate this gain sag, a number of strategies have been employed over the past 8 years of operations, ranging from moving to different lifetime positions, to managing the high voltage to extract a smaller amount of charge, to re-distributing the cenwave usage so that Ly-alpha does not produce a gain-sag hole in a given location. We are now at a point where none of the strategies above will, without any other changes, allow us to continue operating the COS/FUV detector to 2025. To address this a new COS2025 policy was developed, with the goal of retaining full science capability of COS/FUV to 2025. We present an overview of the COS2025 policy, which places restrictions on the G130M cenwaves allowed at Lifetime Position 4 (LP4). We also present a tool which allows users to visualize the COS/FUV wavelength ranges to help users prepare their proposals in the light of the restrictions on the G130M cenwaves.

  20. Strong diameter-dependence of nanowire emission coupled to waveguide modes

    Energy Technology Data Exchange (ETDEWEB)

    Dam, Dick van, E-mail: a.d.v.dam@tue.nl; Haverkort, Jos E. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Abujetas, Diego R.; Sánchez-Gil, José A. [Instituto de Estructura de la Materia (IEM-CSIC), Consejo Superior de Investigaciones Científicas Serrano, 121, 28006 Madrid (Spain); Bakkers, Erik P. A. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Gómez Rivas, Jaime, E-mail: j.gomezrivas@differ.nl [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Dutch Institute for Fundamental Energy Research DIFFER, P.O. Box 6336, 5600 HH Eindhoven (Netherlands)

    2016-03-21

    The emission from nanowires can couple to waveguide modes supported by the nanowire geometry, thus governing the far-field angular pattern. To investigate the geometry-induced coupling of the emission to waveguide modes, we acquire Fourier microscopy images of the photoluminescence of nanowires with diameters ranging from 143 to 208 nm. From the investigated diameter range, we conclude that a few nanometers difference in diameter can abruptly change the coupling of the emission to a specific mode. Moreover, we observe a diameter-dependent width of the Gaussian-shaped angular pattern in the far-field emission. This dependence is understood in terms of interference of the guided modes, which emit at the end facets of the nanowire. Our results are important for the design of quantum emitters, solid state lighting, and photovoltaic devices based on nanowires.

  1. Measurement of fluorescence emission spectrum of few strongly driven atoms using an optical nanofiber.

    Science.gov (United States)

    Das, Manoj; Shirasaki, A; Nayak, K P; Morinaga, M; Le Kien, Fam; Hakuta, K

    2010-08-02

    We show that the fluorescence emission spectrum of few atoms can be measured by using an optical nanofiber combined with the optical heterodyne and photon correlation spectroscopy. The observed fluorescence spectrum of the atoms near the nanofiber shows negligible effects of the atom-surface interaction and agrees well with the Mollow triplet spectrum of free-space atoms at high excitation intensity.

  2. A Strong Limit on the Very-high-energy Emission from GRB 150323A

    Science.gov (United States)

    Abeysekara, A. U.; Archer, A.; Benbow, W.; Bird, R.; Brose, R.; Buchovecky, M.; Bugaev, V.; Connolly, M. P.; Cui, W.; Errando, M.; Falcone, A.; Feng, Q.; Finley, J. P.; Flinders, A.; Fortson, L.; Furniss, A.; Gillanders, G. H.; Hütten, M.; Hanna, D.; Hervet, O.; Holder, J.; Hughes, G.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kar, P.; Kelley-Hoskins, N.; Kertzman, M.; Kieda, D.; Krause, M.; Krennrich, F.; Lang, M. J.; Lin, T. T. Y.; Maier, G.; McArthur, S.; Moriarty, P.; Mukherjee, R.; O’Brien, S.; Ong, R. A.; Park, N.; Perkins, J. S.; Petrashyk, A.; Pohl, M.; Popkow, A.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Rulten, C.; Sadeh, I.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Tyler, J.; Wakely, S. P.; Weiner, O. M.; Weinstein, A.; Wells, R. M.; Wilcox, P.; Wilhelm, A.; Williams, D. A.; Zitzer, B.; VERITAS Collaboration; Vurm, Indrek; Beloborodov, Andrei

    2018-04-01

    On 2015 March 23, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) responded to a Swift-Burst Alert Telescope (BAT) detection of a gamma-ray burst, with observations beginning 270 s after the onset of BAT emission, and only 135 s after the main BAT emission peak. No statistically significant signal is detected above 140 GeV. The VERITAS upper limit on the fluence in a 40-minute integration corresponds to about 1% of the prompt fluence. Our limit is particularly significant because the very-high-energy (VHE) observation started only ∼2 minutes after the prompt emission peaked, and Fermi-Large Area Telescope observations of numerous other bursts have revealed that the high-energy emission is typically delayed relative to the prompt radiation and lasts significantly longer. Also, the proximity of GRB 150323A (z = 0.593) limits the attenuation by the extragalactic background light to ∼50% at 100–200 GeV. We conclude that GRB 150323A had an intrinsically very weak high-energy afterglow, or that the GeV spectrum had a turnover below ∼100 GeV. If the GRB exploded into the stellar wind of a massive progenitor, the VHE non-detection constrains the wind density parameter to be A ≳ 3 × 1011 g cm‑1, consistent with a standard Wolf–Rayet progenitor. Alternatively, the VHE emission from the blast wave would be weak in a very tenuous medium such as the interstellar medium, which therefore cannot be ruled out as the environment of GRB 150323A.

  3. Silver Nanoshell Plasmonically Controlled Emission of Semiconductor Quantum Dots in the Strong Coupling Regime.

    Science.gov (United States)

    Zhou, Ning; Yuan, Meng; Gao, Yuhan; Li, Dongsheng; Yang, Deren

    2016-04-26

    Strong coupling between semiconductor excitons and localized surface plasmons (LSPs) giving rise to hybridized plexciton states in which energy is coherently and reversibly exchanged between the components is vital, especially in the area of quantum information processing from fundamental and practical points of view. Here, in photoluminescence spectra, rather than from common extinction or reflection measurements, we report on the direct observation of Rabi splitting of approximately 160 meV as an indication of strong coupling between excited states of CdSe/ZnS quantum dots (QDs) and LSP modes of silver nanoshells under nonresonant nanosecond pulsed laser excitation at room temperature. The strong coupling manifests itself as an anticrossing-like behavior of the two newly formed polaritons when tuning the silver nanoshell plasmon energies across the exciton line of the QDs. Further analysis substantiates the essentiality of high pump energy and collective strong coupling of many QDs with the radiative dipole mode of the metallic nanoparticles for the realization of strong coupling. Our finding opens up interesting directions for the investigation of strong coupling between LSPs and excitons from the perspective of radiative recombination under easily accessible experimental conditions.

  4. Field emission properties and strong localization effect in conduction mechanism of nanostructured perovskite LaNiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Kamble, Ramesh B., E-mail: rbk.physics@coep.ac.in [Department of Physics, Indian Institute of Science, Bangalore 560012, Karnataka (India); Department of Physics, College of Engineering, Pune 411005, Maharashtra (India); Tanty, Narendra; Patra, Ananya; Prasad, V. [Department of Physics, Indian Institute of Science, Bangalore 560012, Karnataka (India)

    2016-08-22

    We report the potential field emission of highly conducting metallic perovskite lanthanum nickelate (LaNiO{sub 3}) from the nanostructured pyramidal and whisker shaped tips as electron emitters. Nano particles of lanthanum nickelate (LNO) were prepared by sol-gel route. Structural and morphological studies have been carried out. Field emission of LNO exhibited high emission current density, J = 3.37 mA/cm{sup 2} at a low threshold electric field, E{sub th} = 16.91 V/μm, obeying Fowler–Nordheim tunneling. The DC electrical resistivity exhibited upturn at 11.6 K indicating localization of electron at low temperature. Magnetoresistance measurement at different temperatures confirmed strong localization in nanostructured LNO obeying Anderson localization effect at low temperature.

  5. The early-type strong emission-line supergiants of the Magellanic Clouds - A spectroscopic zoology

    Science.gov (United States)

    Shore, S. N.; Sanduleak, N.

    1984-01-01

    The results of a spectroscopic survey of 21 early-type extreme emission line supergiants of the Large and Small Magellanic Clouds using IUE and optical spectra are presented. The combined observations are discussed and the literature on each star in the sample is summarized. The classification procedures and the methods by which effective temperatures, bolometric magnitudes, and reddenings were assigned are discussed. The derived reddening values are given along with some results concerning anomalous reddening among the sample stars. The derived mass, luminosity, and radius for each star are presented, and the ultraviolet emission lines are described. Mass-loss rates are derived and discussed, and the implications of these observations for the evolution of the most massive stars in the Local Group are addressed.

  6. Permafrost thaw strongly reduces allowable CO2 emissions for 1.5°C and 2°C

    Science.gov (United States)

    Kechiar, M.; Gasser, T.; Kleinen, T.; Ciais, P.; Huang, Y.; Burke, E.; Obersteiner, M.

    2017-12-01

    We quantify how the inclusion of carbon emission from permafrost thaw impacts the budgets of allowable anthropogenic CO2 emissions. We use the compact Earth system model OSCAR v2.2 which we expand with a permafrost module calibrated to emulate the behavior of the complex models JSBACH, ORCHIDEE and JULES. When using the "exceedance" method and with permafrost thaw turned off, we find budgets very close to the CMIP5 models' estimates reported by IPCC. With permafrost thaw turned on, the total budgets are reduced by 3-4%. This corresponds to a 33-45% reduction of the remaining budget for 1.5°C, and a 9-13% reduction for 2°C. When using the "avoidance" method, however, permafrost thaw reduces the total budget by 3-7%, which corresponds to reductions by 33-56% and 56-79% of the remaining budget for 1.5°C and 2°C, respectively. The avoidance method relies on many scenarios that actually peak below the target whereas the exceedance method overlooks the carbon emitted by thawed permafrost after the temperature target is reached, which explains the difference. If we use only the subset of scenarios in which there is no net negative emissions, the permafrost-induced reduction in total budgets rises to 6-15%. Permafrost thaw therefore makes the emission budgets strongly path-dependent. We also estimate budgets of needed carbon capture in scenarios overshooting the temperature targets. Permafrost thaw strongly increases these capture budgets: in the case of a 1.5°C target overshot by 0.5°C, which is in line with the Paris agreement, about 30% more carbon must be captured. Our conclusions are threefold. First, inclusion of permafrost thaw systematically reduces the emission budgets, and very strongly so if the temperature target is overshot. Second, the exceedance method, that is the only one that complex models can follow, only partially accounts for the effect of slow non-linear processes such as permafrost thaw, leading to overestimated budgets. Third, the newfound

  7. Can we bet on negative emissions to achieve the 2°C target even under strong carbon cycle feedbacks?

    Science.gov (United States)

    Tanaka, K.; Yamagata, Y.; Yokohata, T.; Emori, S.; Hanaoka, T.

    2015-12-01

    Negative emission technologies such as Bioenergy with Carbon dioxide Capture and Storage (BioCCS) play an ever more crucial role in meeting the 2°C stabilization target. However, such technologies are currently at their infancy and their future penetrations may fall short of the scale required to stabilize the warming. Furthermore, the overshoot in the mid-century prior to a full realization of negative emissions would give rise to a risk because such a temporal but excessive warming above 2°C might amplify itself by strengthening climate-carbon cycle feedbacks. It has not been extensively assessed yet how carbon cycle feedbacks might play out during the overshoot in the context of negative emissions. This study explores how 2°C stabilization pathways, in particular those which undergo overshoot, can be influenced by carbon cycle feedbacks and asks their climatic and economic consequences. We compute 2°C stabilization emissions scenarios under a cost-effectiveness principle, in which the total abatement costs are minimized such that the global warming is capped at 2°C. We employ a reduced-complexity model, the Aggregated Carbon Cycle, Atmospheric Chemistry, and Climate model (ACC2), which comprises a box model of the global carbon cycle, simple parameterizations of the atmospheric chemistry, and a land-ocean energy balance model. The total abatement costs are estimated from the marginal abatement cost functions for CO2, CH4, N2O, and BC.Our preliminary results show that, if carbon cycle feedbacks turn out to be stronger than what is known today, it would incur substantial abatement costs to keep up with the 2°C stabilization goal. Our results also suggest that it would be less expensive in the long run to plan for a 2°C stabilization pathway by considering strong carbon cycle feedbacks because it would cost more if we correct the emission pathway in the mid-century to adjust for unexpectedly large carbon cycle feedbacks during overshoot. Furthermore, our

  8. Electrical control of spontaneous emission and strong coupling for a single quantum dot

    DEFF Research Database (Denmark)

    Laucht, A.; Hofbauer, F.; Hauke, N.

    2009-01-01

    We report the design, fabrication and optical investigation of electrically tunable single quantum dots—photonic crystal defect nanocavities operating in both the weak and strong coupling regimes of the light–matter interaction. Unlike previous studies where the dot–cavity spectral detuning...... switchable optical nonlinearity at the single photon level, paving the way towards on-chip dot-based nano-photonic devices that can be integrated with passive optical components....

  9. Neutrino emission, equation of state and the role of strong gravity

    Energy Technology Data Exchange (ETDEWEB)

    Caballero, O. L., E-mail: ocaballe@uoguelph.ca [Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada)

    2016-07-07

    Neutron-star mergers are interesting for several reasons: they are proposed as the progenitors of short gamma-ray bursts, they have been speculated to be a site for the synthesis of heavy elements, and they emit gravitational waves possibly detectable at terrestrial facilities. The understanding of the merger process, from the pre-merger stage to the final compact object-accreting system involves detailed knowledge of numerical relativity and nuclear physics. In particular, key ingredients for the evolution of the merger are neutrino physics and the matter equation of state. We present some aspects of neutrino emission from binary neutron star mergers showing the impact that the equation of state has on neutrinos and discuss some spectral quantities relevant to their detection such as energies and luminosities far from the source.

  10. All-optical signatures of strong-field QED in the vacuum emission picture

    Science.gov (United States)

    Gies, Holger; Karbstein, Felix; Kohlfürst, Christian

    2018-02-01

    We study all-optical signatures of the effective nonlinear couplings among electromagnetic fields in the quantum vacuum, using the collision of two focused high-intensity laser pulses as an example. The experimental signatures of quantum vacuum nonlinearities are encoded in signal photons, whose kinematic and polarization properties differ from the photons constituting the macroscopic laser fields. We implement an efficient numerical algorithm allowing for the theoretical investigation of such signatures in realistic field configurations accessible in experiment. This algorithm is based on a vacuum emission scheme and can readily be adapted to the collision of more laser beams or further involved field configurations. We solve the case of two colliding pulses in full 3 +1 -dimensional spacetime and identify experimental geometries and parameter regimes with improved signal-to-noise ratios.

  11. US biofuels subsidies and CO2 emissions: An empirical test for a weak and a strong green paradox

    International Nuclear Information System (INIS)

    Grafton, R. Quentin; Kompas, Tom; Long, Ngo Van; To, Hang

    2014-01-01

    Using energy data over the period 1981–2011 we find that US biofuels subsidies and production have provided a perverse incentive for US fossil fuel producers to increase their rate of extraction that has generated a weak green paradox. Further, in the short-run if the reduction in the CO 2 emissions from a one-to-one substitution between biofuels and fossil fuels is less than 26 percent, or less than 57 percent if long run effect is taken into account, then US biofuels production is likely to have resulted in a strong green paradox. These results indicate that subsidies for first generation biofuels, which yield a low level of per unit CO 2 emission reduction compared to fossil fuels, might have contributed to additional net CO 2 emissions over the study period. - Highlights: • US biofuels subsidies increased fossil fuel extraction from 1981 to 2011. • US biofuels subsidies likely increased carbon emissions from 1981 to 2011. • Governments must consider effects of biofuel subsidies on fossil fuel extraction

  12. Strongly emissive perovskite nanocrystal inks for high-voltage solar cells

    Science.gov (United States)

    Akkerman, Quinten A.; Gandini, Marina; di Stasio, Francesco; Rastogi, Prachi; Palazon, Francisco; Bertoni, Giovanni; Ball, James M.; Prato, Mirko; Petrozza, Annamaria; Manna, Liberato

    2016-12-01

    Lead halide perovskite semiconductors have recently gained wide interest following their successful embodiment in solid-state photovoltaic devices with impressive power-conversion efficiencies, while offering a relatively simple and low-cost processability. Although the primary optoelectronic properties of these materials have already met the requirement for high-efficiency optoelectronic technologies, industrial scale-up requires more robust processing methods, as well as solvents that are less toxic than the ones that have been commonly used so successfully on the lab-scale. Here we report a fast, room-temperature synthesis of inks based on CsPbBr3 perovskite nanocrystals using short, low-boiling-point ligands and environmentally friendly solvents. Requiring no lengthy post-synthesis treatments, the inks are directly used to fabricate films of high optoelectronic quality, exhibiting photoluminescence quantum yields higher than 30% and an amplified spontaneous emission threshold as low as 1.5 μJ cm-2. Finally, we demonstrate the fabrication of perovskite nanocrystal-based solar cells, with open-circuit voltages as high as 1.5 V.

  13. Controlled fabrication of the strong emission YVO4:Eu3+ nanoparticles and nanowires by microwave assisted chemical synthesis

    International Nuclear Information System (INIS)

    Huong, Tran Thu; Vinh, Le Thi; Phuong, Ha Thi; Khuyen, Hoang Thi; Anh, Tran Kim; Tu, Vu Duc; Minh, Le Quoc

    2016-01-01

    In this report, we are presenting the controlled fabrication results of the strong emission YVO 4 : Eu 3+ nanoparticles and nanowires by microwave which is assisted chemical synthesis. The effects of incorporated synthesis conditions such as microwave irradiated powers, pH values and concentration of chemical composition on properties of nanomaterials are also investigated to obtain the controllable size and homogenous morphology. Morphological and optical properties of YVO 4 : Eu 3+ prepared products which have been characterized by X-ray diffraction (XRD), field emission micrcroscopy (FESEM) and photoluminescence spectroscopy. As based from result of synthesized samples, we found that the changing of pH values, microwave irradiated powers and chemical composition rise to change reform the size and shape of materials from nanoparticles (diameter about 20 nm) to wires shape (with about 500÷800 nm length and 10÷20 nm width). The photoluminescence (PL) spectroscopy measurements of YVO 4 : Eu 3+ nanostructure materials under UV excitation showed that: the strong luminescence in red region with narrow lines corresponding to the intra-4f transitions of 5 D 0 – 7 F j (j=1, 2, 3, and 4) of Eu 3+ ions with the highest luminescence intensity of 5 D 0 → 7 F 2 transition. - Highlights: • The strong emission YVO 4 :Eu 3+ nanostructure materials were successfully synthesized by microwave assisted chemical synthesis. • The size, morphology and luminescence of the YVO 4 :Eu 3+ nanostructure materials can be controlled by the solution pH, microwave irradiated powers and chemical composition. • These YVO 4 :Eu 3+ nanostructure materials above can potentially applied in various fields of application, especially in luminescent labeling and visualization in biomedical application.

  14. Effect of density distribution of cathode emission on the flux character in a strong-current electron gun

    International Nuclear Information System (INIS)

    Matora, I.M.; Merkulov, L.A.

    1975-01-01

    The effect is considered of two kinds of a dependence of the emission density from the electric field voltage on the emitter surface of a strong-current electron gun (the Schottky law and the ''3/2'' law) upon the choice of a form for the meridional cross section of this emitter at the condition of electron flux laminarity. A calculation example is given for electron gun with close to laminar flow assuming the validity of the Schottky law. The results of calculation of varying the laminar flux character are given which appears when varying parameters of the gun at the voltage 500 kV and current 250 A

  15. Two-step excitation structure changes of luminescence centers and strong tunable blue emission on surface of silica nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lei, E-mail: nanoyang@qq.com; Jiang, Zhongcheng; Dong, Jiazhang; Zhang, Liuqian [Hunan University, College of Materials Science and Engineering (China); Pan, Anlian, E-mail: anlian.pan@gmail.com; Zhuang, Xiujuan [Hunan University, Key Laboratory for Micro-Nano Physics and Technology of Hunan Province (China)

    2015-10-15

    We report a scheme for investigating two-step stimulated structure change of luminescence centers. Amorphous silica nanospheres with uniform diameter of 9–15 nm have been synthesized by Stöber method. Strong hydroxyl-related infrared-absorption band is observed in infrared spectrum. The surface hydroxyl groups exert great influence on the luminescent behavior of silica. They provide stable and intermediate energy states to accommodate excitation electrons. The existence of these surface states reduces the energy barrier of photochemical reactions, creating conditions for two-step excitation process. By carefully examining excitation and emission process, the nearest excitation band is absent in both optical absorption spectrum and excitation spectrum. This later generated state confirms the generation of new luminescence centers as well as the existence of photochemical reactions. Stimulated by different energies, two-step excitation process impels different photochemical reactions, prompting generation of different lattice defects on surface area of silica. Thereby, tunable luminescence is achieved. After thermal treatment, strong gap excitation band appears with the disappearance of strong surface excitation band. Strong blue luminescence also disappears. The research is significance to precise introducing structural defects and controlling position of luminescence peaks.

  16. Temporal Variations of Water Vapor in the Coma of 67P/Churyumov-Gerasimenko as Observed by Rosetta’s Alice FUV Spectrograph

    Science.gov (United States)

    Steffl, Andrew J.; Feaga, Lori M.; A'Hearn, Michael; Bertaux, Jean-Loup; Feldman, Paul D.; Keeney, Brian A.; Knight, Matthew M.; Medina, Richard; Noonan, John; Parker, Joel Wm.; Pineau, Jon; Schindhelm, Eric; Stern, S. Alan; Versteeg, Maarten H.; Vervack, Ronald J.; Weaver, Harold A.

    2017-10-01

    During the Rosetta mission, the Alice far-ultraviolet (FUV) imaging spectrograph obtained spatially-resolved spectra of the coma and nucleus of comet 67P/Churyumov-Gerasimenko over the wavelength range of 700-2050Å. Typically, Alice detected emissions from the neutral atomic daughter and granddaughter products (H, O, C, and S) of the primary molecular species in the coma: H2O, CO2, CO, and O2. However, during a six-month period centered near perihelion, Alice directly detected water vapor in absorption of sunlight reflected from the nucleus. We present here analyses of the water vapor column density as measured by the Alice FUV spectrograph. Alice is sensitive to water vapor at column densities greater than ~1016 cm-2 along the sum of the Sun-nucleus and nucleus-spacecraft lines of sight. Due to the excellent temporal coverage provided by the Alice instrument (exposures were typically obtained every 5-10 minutes), we are able to show variations of water vapor in the coma caused by the changing heliocentric distance of the comet, the comet’s ~12-hour rotation period, and short-term outbursts. We compare our water vapor column densities to those derived from other instruments aboard the Rosetta spacecraft and use models to estimate the water production rate.Rosetta is an ESA mission with contributions from its member states and NASA. The Alice team acknowledges continuing support from NASA’s Jet Propulsion Laboratory through contract 1336850 to the Southwest Research Institute.

  17. Strong blue and white photoluminescence emission of BaZrO{sub 3} undoped and lanthanide doped phosphor for light emitting diodes application

    Energy Technology Data Exchange (ETDEWEB)

    Romero, V.H. [Centro de Investigaciones en Optica, A. P. 1-948, Leon Gto., 37160 (Mexico); De la Rosa, E., E-mail: elder@cio.mx [Centro de Investigaciones en Optica, A. P. 1-948, Leon Gto., 37160 (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro, Qro. 76000 (Mexico); Velazquez-Salazar, J.J. [Department of Physics and Astronomy, The University of Texas at San Antonio One UTSA Circle, San Antonio TX 78249 (United States)

    2012-12-15

    In this paper, we report the obtained strong broadband blue photoluminescence (PL) emission centered at 427 nm for undoped BaZrO{sub 3} observed after 266 nm excitation of submicron crystals prepared by hydrothermal/calcinations method. This emission is enhanced with the introduction of Tm{sup 3+} ions and is stronger than the characteristic PL blue emission of such lanthanide. The proposed mechanism of relaxation for host lattice emission is based on the presence of oxygen vacancies produced during the synthesis process and the charge compensation due to the difference in the electron valence between dopant and substituted ion in the host. Brilliant white light emission with a color coordinate of (x=0.29, y=0.32) was observed by combining the blue PL emission from the host with the green and red PL emission from Tb{sup 3+} and Eu{sup 3+} ions, respectively. The color coordinate can be tuned by changing the ratio between blue, green and red band by changing the concentration of lanthanides. - Graphical abstract: Strong blue emission from undoped BaZrO{sub 3} phosphor and white light emission by doping with Tb{sup 3+} (green) and Eu{sup 3+} (red) after 266 nm excitation. Highlights: Black-Right-Pointing-Pointer Blue emission from BaZrO{sub 3} phosphor. Black-Right-Pointing-Pointer Blue emission enhanced with Tm{sup 3+}. Black-Right-Pointing-Pointer White light from BaZrO{sup 3+} phosphor.

  18. Measurement of Coherent Emission and Linear Polarization of Photons by Electrons in the Strong Fields of Aligned Crystals

    CERN Document Server

    Apyan, A.; Badelek, B.; Ballestrero, S.; Biino, C.; Birol, I.; Cenci, P.; Connell, S.H.; Eichblatt, S.; Fonseca, T.; Freund, A.; Gorini, B.; Groess, R.; Ispirian, K.; Ketel, T.J.; Kononets, Yu.V.; Lopez, A.; Mangiarotti, A.; van Rens, B.; Sellschop, J.P.F.; Shieh, M.; Sona, P.; Strakhovenko, V.; Uggerhoj, E.; Uggerhj, Ulrik Ingerslev; Unel, G.; Velasco, M.; Vilakazi, Z.Z.; Wessely, O.; Kononets, Yu.V.

    2004-01-01

    We present new results regarding the features of high energy photon emission by an electron beam of 178 GeV penetrating a 1.5 cm thick single Si crystal aligned at the Strings-Of-Strings (SOS) orientation. This concerns a special case of coherent bremsstrahlung where the electron interacts with the strong fields of successive atomic strings in a plane and for which the largest enhancement of the highest energy photons is expected. The polarization of the resulting photon beam was measured by the asymmetry of electron-positron pair production in an aligned diamond crystal analyzer. By the selection of a single pair the energy and the polarization of individual photons could be measured in an the environment of multiple photons produced in the radiator crystal. Photons in the high energy region show less than 20% linear polarization at the 90% confidence level.

  19. What is the physical origin of strong Lyα emission? I. Demographics of Lyα emitter structures

    International Nuclear Information System (INIS)

    Shibuya, Takatoshi; Ouchi, Masami; Yuma, Suraphong; Nakajima, Kimihiko; Hashimoto, Takuya; Shimasaku, Kazuhiro; Mori, Masao; Umemura, Masayuki

    2014-01-01

    We present the results of structure analyses for a large sample of 426 Lyα emitters (LAEs) at z ∼ 2.2 that are observed with the Hubble Space Telescope/Advanced Camera for Surveys and WFC3-IR during deep extra-galactic legacy surveys. We confirm that the merger fraction and the average ellipticity of LAE's stellar component are 10%-30% and 0.4-0.6, respectively, that are comparable with previous study results. We successfully identify that some LAEs have a spatial offset between Lyα and stellar-continuum emission peaks, δ Lyα , by ∼2.5-4 kpc beyond our statistical errors. To uncover the physical origin of strong Lyα emission found in LAEs, we investigate the Lyα equivalent width (EW) dependences of three structural parameters: merger fraction, δ Lyα , and ellipticity of stellar distribution in the range of EW(Lyα) = 20-250 Å. Contrary to expectations, we find that the merger fraction does not significantly increase with Lyα EW. We reveal an anti-correlation between δ Lyα and EW(Lyα) using a Kolmogorov-Smirnov (K-S) test. There is a trend that the LAEs with a large Lyα EW have a small ellipticity. This is consistent with the recent theoretical claims that Lyα photons can more easily escape from face-on disks having a small ellipticity, due to less inter-stellar gas along the line of sight, although our K-S test indicates that this trend is not statistically significant. Our results of Lyα-EW dependence generally support the idea that an H I column density is a key quantity determining Lyα emissivity.

  20. Strongly transverse-electric-polarized emission from deep ultraviolet AlGaN quantum well light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Reich, Christoph, E-mail: Christoph.Reich@tu-berlin.de; Guttmann, Martin; Wernicke, Tim; Mehnke, Frank; Kuhn, Christian [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, Berlin 10623 (Germany); Feneberg, Martin; Goldhahn, Rüdiger [Institut für Experimentelle Physik, Otto-von-Guericke-Universität, Universitätsplatz 2, Magdeburg 39106 (Germany); Rass, Jens; Kneissl, Michael [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, Berlin 10623 (Germany); Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, Berlin 12489 (Germany); Lapeyrade, Mickael; Einfeldt, Sven; Knauer, Arne; Kueller, Viola; Weyers, Markus [Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, Berlin 12489 (Germany)

    2015-10-05

    The optical polarization of emission from ultraviolet (UV) light emitting diodes (LEDs) based on (0001)-oriented Al{sub x}Ga{sub 1−x}N multiple quantum wells (MQWs) has been studied by simulations and electroluminescence measurements. With increasing aluminum mole fraction in the quantum well x, the in-plane intensity of transverse-electric (TE) polarized light decreases relative to that of the transverse-magnetic polarized light, attributed to a reordering of the valence bands in Al{sub x}Ga{sub 1−x}N. Using k ⋅ p theoretical model calculations, the AlGaN MQW active region design has been optimized, yielding increased TE polarization and thus higher extraction efficiency for bottom-emitting LEDs in the deep UV spectral range. Using (i) narrow quantum wells, (ii) barriers with high aluminum mole fractions, and (iii) compressive growth on patterned aluminum nitride sapphire templates, strongly TE-polarized emission was observed at wavelengths as short as 239 nm.

  1. Strong visible-light emission of ZnS nanocrystals embedded in sol-gel silica xerogel

    International Nuclear Information System (INIS)

    Yang Ping; Lue, M.-K.; Song, C.-F.; Zhou, G.-J.; Ai, Z.-P.; Xu Dong; Yuan, D.-R.; Cheng, X.-F.

    2003-01-01

    ZnS nanoparticles embedded in novel porous phosphor silica xerogel have been synthesized by sol-gel processing. Their fluorescence properties have been evaluated and compared with those of the Na + -doped and un-doped silica xerogels. Stable and strong visible-light emission of the doped samples has been observed. The relative fluorescence intensities of the samples doped with ZnS nanoparticles (S 2- ions have been obtained by the water solution of NaS) are the highest among all of the doped samples. Its relative fluorescence intensity is about 7.5 times of that of the un-doped silica xerogel and about 300 times of that of pure ZnS nanoparticles. The emission wavelength of the ZnS-doped and Na + -doped samples is the same as that of the un-doped silica xerogel and ZnS nanoparticles (λ em =440-450 nm). This high efficiency luminescence of the doped silica xerogels has been assigned to the luminescence centers of ZnS nanoparticles and Na + in the porous phosphorescence silica xerogel

  2. Rh-Catalyzed annulations of N-methoxybenzamides with ketenimines: synthesis of 3-aminoisoindolinones and 3-diarylmethyleneisoindolinones with strong aggregation induced emission properties.

    Science.gov (United States)

    Zhou, Xiaorong; Peng, Zhixing; Zhao, Hongyang; Zhang, Zhiyin; Lu, Ping; Wang, Yanguang

    2016-08-23

    Rhodium-catalyzed C-H activation/annulation reactions of ketenimines with N-methoxybenzamides furnished 3-aminoisoindolin-1-ones and 3-(diarylmethylene)isoindolin-1-ones. The synthesized 3-(diarylmethylene)isoindolin-1-ones exhibited aggregation induced emissions in aqueous tetrahydrofuran solution and strong green-yellow emissions in solids.

  3. Quantification of strong emissions of methane in the Arctic using spectral measurements from TANSO-FTS and IASI

    Science.gov (United States)

    Bourakkadi, Zakia; Payan, Sébastien; Bureau, Jérôme

    2015-04-01

    Methane is the second most important greenhouse gas after the carbon dioxide but it is 25 times more effective in contributing to the radiative forcing than the carbon dioxide(1). Since the pre-industrial times global methane concentration have more than doubled in the atmosphere. This increase is generally caused by anthropogenic activities like the massif use and extraction of fossil fuel, rice paddy agriculture, emissions from landfills... In recent years, several studies show that climate warming and thawing of permafrost act on the mobilization of old stored carbon in Arctic causing a sustained release of methane to the atmosphere(2),(3),(4). The methane emissions from thawing permafrost and methane hydrates in the northern circumpolar region will become potentially important in the end of the 21st centry because they could increase dramatically due to the rapid climate warming of the Artic and the large carbon pools stored there. The objective of this study is to evaluate and quantify methane strong emissions in this region of the globe using spectral measurements from the Thermal And Near Infrared Sensor for carbon Observations-Fourier Transform Spectrometer (TANSO-FTS) and the Infrared Atmospheric Sounding Interferometer (IASI). We use also the LMDZ-PYVAR model to simulate methane fluxes and to estimate how they could be observed by Infrared Sounders from space. To select spectra with high values of methane we developed a statistical approach based on the singular value decomposition. Using this approach we can identify spectra over the important emission sources of methane and we can by this way reduce the number of spectra to retrieve by an line-by-line radiative transfer model in order to focus on those which contain high amount of methane. In order to estimate the capacity of TANSO-FTS and IASI to detect peaks of methane emission with short duration at quasi-real time, we used data from MACC (Monitoring Atmospheric Composition and Climate) simulations

  4. The comparative effect of FUV, EUV and X-ray disc photoevaporation on gas giant separations

    Science.gov (United States)

    Jennings, Jeff; Ercolano, Barbara; Rosotti, Giovanni P.

    2018-04-01

    Gas giants' early (≲ 5 Myr) orbital evolution occurs in a disc losing mass in part to photoevaporation driven by high energy irradiance from the host star. This process may ultimately overcome viscous accretion to disperse the disc and halt migrating giants by starving their orbits of gas, imprinting on giant planet separations in evolved systems. Inversion of this distribution could then give insight into whether stellar FUV, EUV or X-ray flux dominates photoevaporation, constraining planet formation and disc evolution models. We use a 1D hydrodynamic code in population syntheses for gas giants undergoing Type II migration in a viscously evolving disc subject to either a primarily FUV, EUV or X-ray flux from a pre-solar T Tauri star. The photoevaporative mass loss profile's unique peak location and width in each energetic regime produces characteristic features in the distribution of giant separations: a severe dearth of ≲ 2 MJ planets interior to 5 AU in the FUV scenario, a sharp concentration of ≲ 3 MJ planets between ≈1.5 - 2 AU in the EUV case, and a relative abundance of ≈2 - 3.5 MJ giants interior to 0.5 AU in the X-ray model. These features do not resemble the observational sample of gas giants with mass constraints, though our results do show some weaker qualitative similarities. We thus assess how the differing photoevaporative profiles interact with migrating giants and address the effects of large model uncertainties as a step to better connect disc models with trends in the exoplanet population.

  5. A qubit strongly coupled to a resonant cavity: asymmetry of the spontaneous emission spectrum beyond the rotating wave approximation

    Energy Technology Data Exchange (ETDEWEB)

    Cao, X [Department of Physics and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, 361005 (China); You, J Q; Nori, F [Advanced Science Institute, RIKEN, Wako-shi 351-0198 (Japan); Zheng, H, E-mail: xfcao@xmu.edu.cn [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2011-07-15

    We investigate the spontaneous emission (SE) spectrum of a qubit in a lossy resonant cavity. We use neither the rotating-wave approximation nor the Markov approximation. For the weak-coupling case, the SE spectrum of the qubit is a single peak, with its location depending on the spectral density of the qubit environment. Then, the asymmetry (of the location and heights of the two peaks) of the two SE peaks (which are related to the vacuum Rabi splitting) changes as the qubit-cavity coupling increases. Explicitly, for a qubit in a low-frequency intrinsic bath, the height asymmetry of the splitting peaks is enhanced as the qubit-cavity coupling strength increases. However, for a qubit in an Ohmic bath, the height asymmetry of the spectral peaks is inverted compared to the low-frequency bath case. With further increasing the qubit-cavity coupling to the ultra-strong regime, the height asymmetry of the left and right peaks is slightly inverted, which is consistent with the corresponding case of a low-frequency bath. This inversion of the asymmetry arises from the competition between the Ohmic bath and the cavity bath. Therefore, after considering the anti-rotating terms, our results explicitly show how the height asymmetry in the SE spectrum peaks depends on the qubit-cavity coupling and the type of intrinsic noise experienced by the qubit.

  6. Observations of Local ISM Emission with the Berkeley EUV/FUV Shuttle Telescope

    Science.gov (United States)

    Martin, C.; Bowyer, S.

    1984-01-01

    The Berkeley extreme ultraviolet/far ultraviolet shuttle telescope (BEST) will be launched on the Space Shuttle as part of the NASA UVX project. The Berkeley spectrometer will make observations of the cosmic diffuse background in the 600 to 1900 A band, with a spectral resolution of 10 A. The sensitivity and spectral resolution of the instrument make it ideal for the study of components of the interstellar medium in the 10 to the 4th power to 10 to the 6th power K range.

  7. A Deep Chandra ACIS Study of NGC 4151. II. The Innermost Emission Line Region and Strong Evidence for Radio Jet-NLR Cloud Collision

    Science.gov (United States)

    Wang, Junfeng; Fabbiano, Giuseppina; Elvis, Martin; Risaliti, Guido; Mundell, Carole G.; Karovska, Margarita; Zezas, Andreas

    2011-07-01

    We have studied the X-ray emission within the inner ~150 pc radius of NGC 4151 by constructing high spatial resolution emission line images of blended O VII, O VIII, and Ne IX. These maps show extended structures that are spatially correlated with the radio outflow and optical [O III] emission. We find strong evidence for jet-gas cloud interaction, including morphological correspondences with regions of X-ray enhancement, peaks of near-infrared [Fe II] emission, and optical clouds. In these regions, moreover, we find evidence of elevated Ne IX/O VII ratios; the X-ray emission of these regions also exceeds that expected from nuclear photoionization. Spectral fitting reveals the presence of a collisionally ionized component. The thermal energy of the hot gas suggests that >~ 0.1% of the estimated jet power is deposited into the host interstellar medium through interaction between the radio jet and the dense medium of the circumnuclear region. We find possible pressure equilibrium between the collisionally ionized hot gas and the photoionized line-emitting cool clouds. We also obtain constraints on the extended iron and silicon fluorescent emission. Both lines are spatially unresolved. The upper limit on the contribution of an extended emission region to the Fe Kα emission is <~ 5% of the total, in disagreement with a previous claim that 65% of the Fe Kα emission originates in the extended narrow line region.

  8. A DEEP CHANDRA ACIS STUDY OF NGC 4151. II. THE INNERMOST EMISSION LINE REGION AND STRONG EVIDENCE FOR RADIO JET-NLR CLOUD COLLISION

    International Nuclear Information System (INIS)

    Wang Junfeng; Fabbiano, Giuseppina; Elvis, Martin; Risaliti, Guido; Karovska, Margarita; Zezas, Andreas; Mundell, Carole G.

    2011-01-01

    We have studied the X-ray emission within the inner ∼150 pc radius of NGC 4151 by constructing high spatial resolution emission line images of blended O VII, O VIII, and Ne IX. These maps show extended structures that are spatially correlated with the radio outflow and optical [O III] emission. We find strong evidence for jet-gas cloud interaction, including morphological correspondences with regions of X-ray enhancement, peaks of near-infrared [Fe II] emission, and optical clouds. In these regions, moreover, we find evidence of elevated Ne IX/O VII ratios; the X-ray emission of these regions also exceeds that expected from nuclear photoionization. Spectral fitting reveals the presence of a collisionally ionized component. The thermal energy of the hot gas suggests that ∼> 0.1% of the estimated jet power is deposited into the host interstellar medium through interaction between the radio jet and the dense medium of the circumnuclear region. We find possible pressure equilibrium between the collisionally ionized hot gas and the photoionized line-emitting cool clouds. We also obtain constraints on the extended iron and silicon fluorescent emission. Both lines are spatially unresolved. The upper limit on the contribution of an extended emission region to the Fe Kα emission is ∼< 5% of the total, in disagreement with a previous claim that 65% of the Fe Kα emission originates in the extended narrow line region.

  9. Comparison of Nitrogen Incorporation in Tholins Produced by FUV Irradiation and Spark Discharge

    Science.gov (United States)

    Horst, S. M.; DeWitt, H. L.; Trainer, M. G.; Tolbert, M. A.

    2012-01-01

    The discovery of very heavy ions (Coates et al., 2007) in Titan's thermosphere has dramatically altered our understanding of the processes involved in the formation of the complex organic aerosols that comprise Titan's characteristic haze. Before Cassini's arrival, it was believed that aerosol production began in the stratosphere where the chemical processes were predominantly initiated by FUV radiation. This understanding guided the design of Titan atmosphere simulation experiments. However, the energy environment of the thermosphere is significantly different than the stratosphere; in particular there is a greater flux of EUV photons and energetic particles available to initiate chemical reactions, including the destruction of N2. in the upper atmosphere. Using a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS), we have obtained in situ composition measurements of aerosol particles (so'called "tholins") produced in CH4/N2 gas mixtures subjected to either FUV radiation (deuterium lamp, 115-400 nm) (Trainer et al., 2012) or a spark discharge. A comparison of the composition of tholins produced using the two different energy sources will be presented, in particular with regard to the variation in nitrogen content of the two types of tholin. Titan's aerosols are known to contain significant amounts of nitrogen (Israel et al., 2005) and therefore understanding the role of nitrogen in the aerosol chemistry is important to further our knowledge of the formation and evolution of aerosols in Titan's atmosphere.

  10. Updated Status and Performance at the Fourth HST COS FUV Lifetime Position

    Science.gov (United States)

    Taylor, Joanna M.; De Rosa, Gisella; Fix, Mees B.; Fox, Andrew; Indriolo, Nick; James, Bethan; Jedrzejewski, Robert I.; Oliveira, Cristina M.; Penton, Steven V.; Plesha, Rachel; Proffitt, Charles R.; Rafelski, Marc; Roman-Duval, Julia; Sahnow, David J.; Snyder, Elaine M.; Sonnentrucker, Paule; White, James

    2017-06-01

    To mitigate the adverse effects of gain sag on the spectral quality and accuracy of Hubble Space Telescope’s Cosmic Origins Spectrograph FUV observations, COS FUV spectra will be moved from Lifetime Position 3 (LP3) to a new pristine location on the detectors at LP4 in July 2017. To achieve maximal spectral resolution while preserving detector area, the spectra will be shifted in the cross-dispersion (XD) direction by -2.5" (about -31 pixels) from LP3 or -5” (about 62 pixels) from the original LP1. At LP4, the wavelength calibration lamp spectrum can overlap with the previously gain-sagged LP2 PSA spectrum location. If lamp lines fall in the gain sag holes from LP2, it can cause line ratios to change and the wavelength calibration to fail. As a result, we have updated the Wavecal Parameters Reference Table and CalCOS to address this issue. Additionally, it was necessary to extend the current geometric correction in order to encompass the entire LP4 location. Here we present 2-D template profiles and 1-D spectral trace centroids derived at LP4 as well as LP4-related updates to the wavelength calibration, and geometric correction.

  11. High Br- Content CsPb(Cl yBr1- y)3 Perovskite Nanocrystals with Strong Mn2+ Emission through Diverse Cation/Anion Exchange Engineering.

    Science.gov (United States)

    Li, Fei; Xia, Zhiguo; Pan, Caofeng; Gong, Yue; Gu, Lin; Liu, Quanlin; Zhang, Jin Z

    2018-04-11

    The unification of tunable band edge (BE) emission and strong Mn 2+ doping luminescence in all-inorganic cesium lead halide perovskite nanocrystals (NCs) CsPbX 3 (X = Cl and Br) is of fundamental importance in fine tuning their optical properties. Herein, we demonstrate that benefiting from the differentiation of the cation/anion exchange rate, ZnBr 2 and preformed CsPb 1- x Cl 3 : xMn 2+ NCs can be used to obtain high Br - content Cs(Pb 1- x- z Zn z )(Cl y Br 1- y ) 3 : xMn 2+ perovskite NCs with strong Mn 2+ emission, and the Mn 2+ substitution ratio can reach about 22%. More specifically, the fast anion exchange could be realized by the soluble halide precursors, leading to anion exchange within a few seconds as observed from the strong BE emission evolution, whereas the cation exchange instead generally required at least a few hours; moreover, their exchange mechanism and dynamics process have been evaluated. The Mn 2+ emission intensity could be further varied by controlling the replacement of Mn 2+ by Zn 2+ with prolonged ion exchange reaction time. White light emission of the doped perovskite NCs via this cation/anion synergistic exchange strategy has been realized, which was also successfully demonstrated in a prototype white light-emitting diode (LED) device based on a commercially available 365 nm LED chip.

  12. Detailed observations of NGC 4151 with IUE-III. Variability of the strong emission lines from 1978 February to 1980 May

    International Nuclear Information System (INIS)

    Ulrich, M.H.; Boksenberg, A.; Bromage, G.E.

    1983-11-01

    Observations of the variability of the three strong ultraviolet emission lines in the Seyfert galaxy NGC 4151 (CIV, CIII, and MgII) are used to study the structure of the broad line region and the nuclear energy source of this active galaxy. (author)

  13. OPTICAL LINE EMISSION IN BRIGHTEST CLUSTER GALAXIES AT 0 < z < 0.6: EVIDENCE FOR A LACK OF STRONG COOL CORES 3.5 Gyr AGO?

    International Nuclear Information System (INIS)

    McDonald, Michael

    2011-01-01

    In recent years the number of known galaxy clusters beyond z ∼> 0.2 has increased drastically with the release of multiple catalogs containing >30,000 optically detected galaxy clusters over the range 0 0.3, hinting at an earlier epoch of strong cooling. We compare the evolution of emission-line nebulae to the X-ray-derived cool core (CC) fraction from the literature over the same redshift range and find overall agreement, with the exception that an upturn in the strong CC fraction is not observed at z > 0.3. The overall agreement between the evolution of CCs and optical line emission at low redshift suggests that emission-line surveys of galaxy clusters may provide an efficient method of indirectly probing the evolution of CCs and thus provide insights into the balance of heating and cooling processes at early cosmic times.

  14. Spatial variability of nitrous oxide and methane emissions from an MBT landfill in operation: Strong N2O hotspots at the working face

    International Nuclear Information System (INIS)

    Harborth, Peter; Fuß, Roland; Münnich, Kai; Flessa, Heinz; Fricke, Klaus

    2013-01-01

    Highlights: ► First measurements of N 2 O and CH 4 emissions from an MBT landfill. ► High N 2 O emissions from recently deposited material. ► N 2 O emissions associated with aeration and the occurrence of nitrite and nitrate. ► Strong negative correlation between CH 4 and N 2 O production activity. - Abstract: Mechanical biological treatment (MBT) is an effective technique, which removes organic carbon from municipal solid waste (MSW) prior to deposition. Thereby, methane (CH 4 ) production in the landfill is strongly mitigated. However, direct measurements of greenhouse gas emissions from full-scale MBT landfills have not been conducted so far. Thus, CH 4 and nitrous oxide (N 2 O) emissions from a German MBT landfill in operation as well as their concentrations in the landfill gas (LFG) were measured. High N 2 O emissions of 20–200 g CO 2 eq. m −2 h −1 magnitude (up to 428 mg N m −2 h −1 ) were observed within 20 m of the working face. CH 4 emissions were highest at the landfill zone located at a distance of 30–40 m from the working face, where they reached about 10 g CO 2 eq. m −2 h −1 . The MBT material in this area has been deposited several weeks earlier. Maximum LFG concentration for N 2 O was 24.000 ppmv in material below the emission hotspot. At a depth of 50 cm from the landfill surface a strong negative correlation between N 2 O and CH 4 concentrations was observed. From this and from the distribution pattern of extractable ammonium, nitrite, and nitrate it has been concluded that strong N 2 O production is associated with nitrification activity and the occurrence of nitrite and nitrate, which is initiated by oxygen input during waste deposition. Therefore, CH 4 mitigation measures, which often employ aeration, could result in a net increase of GHG emissions due to increased N 2 O emissions, especially at MBT landfills

  15. Spatial variability of nitrous oxide and methane emissions from an MBT landfill in operation: Strong N{sub 2}O hotspots at the working face

    Energy Technology Data Exchange (ETDEWEB)

    Harborth, Peter, E-mail: p.harborth@tu-bs.de [Department of Waste and Resource Management, Leichtweiß-Institute for Hydraulic Engineering and Water Resources, Technische Universität Braunschweig, Braunschweig (Germany); Fuß, Roland [Institute of Climate-Smart Agriculture, Johann Heinrich von Thünen Institute, Braunschweig (Germany); Münnich, Kai [Department of Waste and Resource Management, Leichtweiß-Institute for Hydraulic Engineering and Water Resources, Technische Universität Braunschweig, Braunschweig (Germany); Flessa, Heinz [Institute of Climate-Smart Agriculture, Johann Heinrich von Thünen Institute, Braunschweig (Germany); Fricke, Klaus [Department of Waste and Resource Management, Leichtweiß-Institute for Hydraulic Engineering and Water Resources, Technische Universität Braunschweig, Braunschweig (Germany)

    2013-10-15

    Highlights: ► First measurements of N{sub 2}O and CH{sub 4} emissions from an MBT landfill. ► High N{sub 2}O emissions from recently deposited material. ► N{sub 2}O emissions associated with aeration and the occurrence of nitrite and nitrate. ► Strong negative correlation between CH{sub 4} and N{sub 2}O production activity. - Abstract: Mechanical biological treatment (MBT) is an effective technique, which removes organic carbon from municipal solid waste (MSW) prior to deposition. Thereby, methane (CH{sub 4}) production in the landfill is strongly mitigated. However, direct measurements of greenhouse gas emissions from full-scale MBT landfills have not been conducted so far. Thus, CH{sub 4} and nitrous oxide (N{sub 2}O) emissions from a German MBT landfill in operation as well as their concentrations in the landfill gas (LFG) were measured. High N{sub 2}O emissions of 20–200 g CO{sub 2} eq. m{sup −2} h{sup −1} magnitude (up to 428 mg N m{sup −2} h{sup −1}) were observed within 20 m of the working face. CH{sub 4} emissions were highest at the landfill zone located at a distance of 30–40 m from the working face, where they reached about 10 g CO{sub 2} eq. m{sup −2} h{sup −1}. The MBT material in this area has been deposited several weeks earlier. Maximum LFG concentration for N{sub 2}O was 24.000 ppmv in material below the emission hotspot. At a depth of 50 cm from the landfill surface a strong negative correlation between N{sub 2}O and CH{sub 4} concentrations was observed. From this and from the distribution pattern of extractable ammonium, nitrite, and nitrate it has been concluded that strong N{sub 2}O production is associated with nitrification activity and the occurrence of nitrite and nitrate, which is initiated by oxygen input during waste deposition. Therefore, CH{sub 4} mitigation measures, which often employ aeration, could result in a net increase of GHG emissions due to increased N{sub 2}O emissions, especially at MBT landfills.

  16. Cloud-Resolving Model Simulations of Aerosol-Cloud Interactions Triggered by Strong Aerosol Emissions in the Arctic

    Science.gov (United States)

    Wang, H.; Kravitz, B.; Rasch, P. J.; Morrison, H.; Solomon, A.

    2014-12-01

    Previous process-oriented modeling studies have highlighted the dependence of effectiveness of cloud brightening by aerosols on cloud regimes in warm marine boundary layer. Cloud microphysical processes in clouds that contain ice, and hence the mechanisms that drive aerosol-cloud interactions, are more complicated than in warm clouds. Interactions between ice particles and liquid drops add additional levels of complexity to aerosol effects. A cloud-resolving model is used to study aerosol-cloud interactions in the Arctic triggered by strong aerosol emissions, through either geoengineering injection or concentrated sources such as shipping and fires. An updated cloud microphysical scheme with prognostic aerosol and cloud particle numbers is employed. Model simulations are performed in pure super-cooled liquid and mixed-phase clouds, separately, with or without an injection of aerosols into either a clean or a more polluted Arctic boundary layer. Vertical mixing and cloud scavenging of particles injected from the surface is still quite efficient in the less turbulent cold environment. Overall, the injection of aerosols into the Arctic boundary layer can delay the collapse of the boundary layer and increase low-cloud albedo. The pure liquid clouds are more susceptible to the increase in aerosol number concentration than the mixed-phase clouds. Rain production processes are more effectively suppressed by aerosol injection, whereas ice precipitation (snow) is affected less; thus the effectiveness of brightening mixed-phase clouds is lower than for liquid-only clouds. Aerosol injection into a clean boundary layer results in a greater cloud albedo increase than injection into a polluted one, consistent with current knowledge about aerosol-cloud interactions. Unlike previous studies investigating warm clouds, the impact of dynamical feedback due to precipitation changes is small. According to these results, which are dependent upon the representation of ice nucleation

  17. Dissolved organic carbon and nitrogen mineralization strongly affect co2 emissions following lime application to acidic soil

    International Nuclear Information System (INIS)

    Shaaban, M.; Peng, Q.; Lin, S.; Wu, Y.

    2014-01-01

    Emission of greenhouse gases from agricultural soils has main contribution to the climatic change and global warming. Dynamics of dissolved organic carbon (DOC) and nitrogen mineralization can affect CO/sub 2/ emission from soils. Influence of DOC and nitrogen mineralization on CO/sub 2/ emissions following lime application to acidic soil was investigated in current study. Laboratory experiment was conducted under aerobic conditions with 25% moisture contents (66% water-filled pore space) at 25 degree C in the dark conditions. Different treatments of lime were applied to acidic soil as follows: CK (control), L (low rate of lime: 0.2g lime / 100 g soil) and H (high rate of lime: 0.5g lime /100g soil). CO/sub 2/ emissions were measured by gas chromatography and dissolved organic carbon, NH4 +-N, NO/sub 3/ --N and soil pH were measured during incubation study. Addition of lime to acidic soil significantly increased the concentration of DOC and N mineralization rate. Higher concentrations of DOC and N mineralization, consequently, increased the CO/sub 2/ emissions from lime treated soils. Cumulative CO/sub 2/ emission was 75% and 71% higher from L and H treatments as compared to CK. The results of current study suggest that DOC and N mineralization are critical in controlling gaseous emissions of CO/sub 2/ from acidic soils following lime application. (author)

  18. Delayed electron emission in strong-field driven tunnelling from a metallic nanotip in the multi-electron regime

    Science.gov (United States)

    Yanagisawa, Hirofumi; Schnepp, Sascha; Hafner, Christian; Hengsberger, Matthias; Kim, Dong Eon; Kling, Matthias F.; Landsman, Alexandra; Gallmann, Lukas; Osterwalder, Jürg

    2016-01-01

    Illuminating a nano-sized metallic tip with ultrashort laser pulses leads to the emission of electrons due to multiphoton excitations. As optical fields become stronger, tunnelling emission directly from the Fermi level becomes prevalent. This can generate coherent electron waves in vacuum leading to a variety of attosecond phenomena. Working at high emission currents where multi-electron effects are significant, we were able to characterize the transition from one regime to the other. Specifically, we found that the onset of laser-driven tunnelling emission is heralded by the appearance of a peculiar delayed emission channel. In this channel, the electrons emitted via laser-driven tunnelling emission are driven back into the metal, and some of the electrons reappear in the vacuum with some delay time after undergoing inelastic scattering and cascading processes inside the metal. Our understanding of these processes gives insights on attosecond tunnelling emission from solids and should prove useful in designing new types of pulsed electron sources. PMID:27786287

  19. Spatial variability of nitrous oxide and methane emissions from an MBT landfill in operation: strong N2O hotspots at the working face.

    Science.gov (United States)

    Harborth, Peter; Fuss, Roland; Münnich, Kai; Flessa, Heinz; Fricke, Klaus

    2013-10-01

    Mechanical biological treatment (MBT) is an effective technique, which removes organic carbon from municipal solid waste (MSW) prior to deposition. Thereby, methane (CH4) production in the landfill is strongly mitigated. However, direct measurements of greenhouse gas emissions from full-scale MBT landfills have not been conducted so far. Thus, CH4 and nitrous oxide (N2O) emissions from a German MBT landfill in operation as well as their concentrations in the landfill gas (LFG) were measured. High N2O emissions of 20-200gCO2eq.m(-2)h(-1) magnitude (up to 428mgNm(-2)h(-1)) were observed within 20m of the working face. CH4 emissions were highest at the landfill zone located at a distance of 30-40m from the working face, where they reached about 10gCO2eq.m(-2)h(-1). The MBT material in this area has been deposited several weeks earlier. Maximum LFG concentration for N2O was 24.000ppmv in material below the emission hotspot. At a depth of 50cm from the landfill surface a strong negative correlation between N2O and CH4 concentrations was observed. From this and from the distribution pattern of extractable ammonium, nitrite, and nitrate it has been concluded that strong N2O production is associated with nitrification activity and the occurrence of nitrite and nitrate, which is initiated by oxygen input during waste deposition. Therefore, CH4 mitigation measures, which often employ aeration, could result in a net increase of GHG emissions due to increased N2O emissions, especially at MBT landfills. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. The Chandra M10l Megasecond: Diffuse Emission

    Science.gov (United States)

    Kuntz, K. D.; Snowden, S. L.

    2009-01-01

    Because MIOl is nearly face-on, it provides an excellent laboratory in which to study the distribution of X-ray emitting gas in a typical late-type spiral galaxy. We obtained a Chandra observation with a cumulative exposure of roughly 1 Ms to study the diffuse X-ray emission in MlOl. The bulk of the X-ray emission is correlated with the star formation traced by the FUV emission. The global FUV/Xray correlation is non-linear (the X-ray surface brightness is roughly proportional to the square root of the FUV surface brightness) and the small-scale correlation is poor, probably due to the delay between the FUV emission and the X-ray production ill star-forming regions. The X-ray emission contains only minor contributions from unresolved stars (approximates less than 3%), unresolved X-ray point sources (approximates less than 4%), and individual supernova remnants (approximates 3%). The global spectrum of the diffuse emission can be reasonably well fitted with a three component thermal model, but the fitted temperatures are not unique; many distributions of emission measure can produce the same temperatures when observed with the current CCD energy resolution. The spectrum of the diffuse emission depends on the environment; regions with higher X-ray surface brightnesses have relatively stronger hard components, but there is no significant evidence that the temperatures of the emitting components increase with surface brightness.

  1. (F)UV Spectroscopy of K648: Abundance Determination of Trace Elements

    Science.gov (United States)

    Mohamad-Yob, S. J.; Ziegler, M.; Rauch, T.; Werner, K.

    2010-11-01

    We present preliminary results of an ongoing spectral analysis of K 648, the central star of the planetary nebula Ps 1, based on high resolution FUV spectra. K 648, in M 15 is one of only four known PNe in globular clusters. The formation of this post-AGB object in a globular cluster is still unclear. Our aim is to determine Teff, log g, and the abundances of trace elements, in order to improve our understanding of post-AGB evolution of extremely metal-poor stars, especially PN formation in globular clusters. We analyzed FUSE, HST/STIS, and HST/FOS observations. A grid of stellar model atmospheres was calculated using the Tübingen NLTE Model Atmosphere Package (TMAP).

  2. EXTREMELY STRONG CARBON-MONOXIDE EMISSION FROM THE CLOVERLEAF QUASAR AT A REDSHIFT OF 2.5

    NARCIS (Netherlands)

    BARVAINIS, R; TACCONI, L; ANTONUCCI, R; ALLOIN, D; COLEMAN, P

    1994-01-01

    GALAXIES at high redshift are very faint and difficult to study at optical and near-infrared wavelengths, but detection of far-infrared emission(1) and molecular gas(2,3) in a galaxy at redshift z approximate to 2.3 has suggested that their early evolution may be investigated by these means instead.

  3. Towards space based verification of CO2 emissions from strong localized sources: fossil fuel power plant emissions as seen by a CarbonSat constellation

    Directory of Open Access Journals (Sweden)

    T. Krings

    2011-12-01

    Full Text Available Carbon dioxide (CO2 is the most important man-made greenhouse gas (GHG that cause global warming. With electricity generation through fossil-fuel power plants now being the economic sector with the largest source of CO2, power plant emissions monitoring has become more important than ever in the fight against global warming. In a previous study done by Bovensmann et al. (2010, random and systematic errors of power plant CO2 emissions have been quantified using a single overpass from a proposed CarbonSat instrument. In this study, we quantify errors of power plant annual emission estimates from a hypothetical CarbonSat and constellations of several CarbonSats while taking into account that power plant CO2 emissions are time-dependent. Our focus is on estimating systematic errors arising from the sparse temporal sampling as well as random errors that are primarily dependent on wind speeds. We used hourly emissions data from the US Environmental Protection Agency (EPA combined with assimilated and re-analyzed meteorological fields from the National Centers of Environmental Prediction (NCEP. CarbonSat orbits were simulated as a sun-synchronous low-earth orbiting satellite (LEO with an 828-km orbit height, local time ascending node (LTAN of 13:30 (01:30 p.m. LT and achieves global coverage after 5 days. We show, that despite the variability of the power plant emissions and the limited satellite overpasses, one CarbonSat has the potential to verify reported US annual CO2 emissions from large power plants (≥5 Mt CO2 yr−1 with a systematic error of less than ~4.9% and a random error of less than ~6.7% for 50% of all the power plants. For 90% of all the power plants, the systematic error was less than ~12.4% and the random error was less than ~13%. We additionally investigated two different satellite configurations using a combination of 5 CarbonSats. One achieves global coverage everyday but only samples the targets at fixed local times. The other

  4. Spatially Resolved Patchy Ly α Emission within the Central Kiloparsec of a Strongly Lensed Quasar Host Galaxy at z = 2.8

    Energy Technology Data Exchange (ETDEWEB)

    Bayliss, Matthew B.; Bordoloi, Rongmon [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Sharon, Keren; Runnoe, Jessie; Johnson, Traci; Paterno-Mahler, Rachel [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Acharyya, Ayan; Bian, Fuyan; Kewley, Lisa [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Gladders, Michael D. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Rigby, Jane R. [Astrophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Dahle, Hakon [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); Florian, Michael, E-mail: mbayliss@mit.edu [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

    2017-08-20

    We report the detection of extended Ly α emission from the host galaxy of SDSS J2222+2745, a strongly lensed quasar at z = 2.8. Spectroscopic follow-up clearly reveals extended Ly α in emission between two images of the central active galactic nucleus (AGN). We reconstruct the lensed quasar host galaxy in the source plane by applying a strong lens model to HST imaging and resolve spatial scales as small as ∼200 pc. In the source plane, we recover the host galaxy morphology to within a few hundred parsecs of the central AGN and map the extended Ly α emission to its physical origin on one side of the host galaxy at radii ∼0.5–2 kpc from the central AGN. There are clear morphological differences between the Ly α and rest-frame ultraviolet stellar continuum emission from the quasar host galaxy. Furthermore, the relative velocity profiles of quasar Ly α , host galaxy Ly α , and metal lines in outflowing gas reveal differences in the absorbing material affecting the AGN and host galaxy. These data indicate the presence of patchy local intervening gas in front of the central quasar and its host galaxy. This interpretation is consistent with the central luminous quasar being obscured across a substantial fraction of its surrounding solid angle, resulting in strong anisotropy in the exposure of the host galaxy to ionizing radiation from the AGN. This work demonstrates the power of strong-lensing-assisted studies to probe spatial scales that are currently inaccessible by other means.

  5. Spatially Resolved Patchy Ly α Emission within the Central Kiloparsec of a Strongly Lensed Quasar Host Galaxy at z = 2.8

    International Nuclear Information System (INIS)

    Bayliss, Matthew B.; Bordoloi, Rongmon; Sharon, Keren; Runnoe, Jessie; Johnson, Traci; Paterno-Mahler, Rachel; Acharyya, Ayan; Bian, Fuyan; Kewley, Lisa; Gladders, Michael D.; Rigby, Jane R.; Dahle, Hakon; Florian, Michael

    2017-01-01

    We report the detection of extended Ly α emission from the host galaxy of SDSS J2222+2745, a strongly lensed quasar at z = 2.8. Spectroscopic follow-up clearly reveals extended Ly α in emission between two images of the central active galactic nucleus (AGN). We reconstruct the lensed quasar host galaxy in the source plane by applying a strong lens model to HST imaging and resolve spatial scales as small as ∼200 pc. In the source plane, we recover the host galaxy morphology to within a few hundred parsecs of the central AGN and map the extended Ly α emission to its physical origin on one side of the host galaxy at radii ∼0.5–2 kpc from the central AGN. There are clear morphological differences between the Ly α and rest-frame ultraviolet stellar continuum emission from the quasar host galaxy. Furthermore, the relative velocity profiles of quasar Ly α , host galaxy Ly α , and metal lines in outflowing gas reveal differences in the absorbing material affecting the AGN and host galaxy. These data indicate the presence of patchy local intervening gas in front of the central quasar and its host galaxy. This interpretation is consistent with the central luminous quasar being obscured across a substantial fraction of its surrounding solid angle, resulting in strong anisotropy in the exposure of the host galaxy to ionizing radiation from the AGN. This work demonstrates the power of strong-lensing-assisted studies to probe spatial scales that are currently inaccessible by other means.

  6. Mechanically induced strong red emission in samarium ions doped piezoelectric semiconductor CaZnOS for dynamic pressure sensing and imaging

    Science.gov (United States)

    Wang, Wei; Peng, Dengfeng; Zhang, Hanlu; Yang, Xiaohong; Pan, Caofeng

    2017-07-01

    Piezoelectric semiconductor with optical, electrical and mechanical multifunctions has great potential applications in future optoelectronic devices. The rich properties and applications mainly encompass the intrinsic structures and their coupling effects. Here, we report that lanthanide ions doped piezoelectric semiconductor CaZnOS:Sm3+ showing strong red emission induced by dynamic mechanical stress. Under moderate mechanical load, the doped piezoelectric semiconductor exhibits strong visible red emission to the naked eyes even under the day light. A flexible dynamic pressure sensor device is fabricated based on the prepared CaZnOS:Sm3+ powders. The mechanical-induced emission properties of the device are investigated by the optical fiber spectrometer. The linear characteristic emissions are attributed to the 4G5/2→6H5/2 (566 nm), 4G5/2→6H7/2 (580-632 nm), 4G5/2→6H9/2 (653-673 nm) and 4G5/2→6H11/2 (712-735 nm) f-f transitions of Sm3+ ions. The integral emission intensity is proportional to the value of applied pressure. By using the linear relationship between integrated emission intensity and the dynamic pressure, the real-time pressure distribution is visualized and recorded. Our results highlight that the incorporation of lanthanide luminescent ions into piezoelectric semiconductors as smart materials could be applied into the flexible mechanical-optical sensor device without additional auxiliary power, which has great potential for promising applications such as mapping of personalized handwriting, smart display, and human machine interface.

  7. Discovery of γ-ray Emission from the Strongly Lobe-dominated Quasar 3C 275.1

    Science.gov (United States)

    Liao, Neng-Hui; Xin, Yu-Liang; Li, Shang; Jiang, Wei; Liang, Yun-Feng; Li, Xiang; Zhang, Peng-Fei; Chen, Liang; Bai, Jin-Ming; Fan, Yi-Zhong

    2015-07-01

    We systematically analyze the 6 year Fermi/Large Area Telescope (LAT) data on lobe-dominated quasars (LDQs) in the complete LDQ sample from the Revised third Cambridge Catalogue of Radio Sources (3CRR) survey and report the discovery of high-energy γ-ray emission from 3C 275.1. The γ-ray emission of 3C 207 is confirmed and significant variability of the light curve is identified. We do not find statistically significant γ-ray emission from other LDQs. 3C 275.1 is the known γ-ray quasar with the lowest core dominance parameter (i.e., R = 0.11). We also show that both the northern radio hotspot and parsec jet models can reasonably reproduce the γ-ray data. The parsec jet model, however, is favored by the potential γ-ray variability on a timescale of months. We suggest that some dimmer γ-ray LDQs will be detected in the future and LDQs could contribute non-ignorably to the extragalactic γ-ray background.

  8. Radio emission from the X-ray pulsar Her X-1: a jet launched by a strong magnetic field neutron star?

    Science.gov (United States)

    van den Eijnden, J.; Degenaar, N.; Russell, T. D.; Miller-Jones, J. C. A.; Wijnands, R.; Miller, J. M.; King, A. L.; Rupen, M. P.

    2018-01-01

    Her X-1 is an accreting neutron star (NS) in an intermediate-mass X-ray binary. Like low-mass X-ray binaries (LMXBs), it accretes via Roche lobe overflow, but similar to many high-mass X-ray binaries containing a NS; Her X-1 has a strong magnetic field and slow spin. Here, we present the discovery of radio emission from Her X-1 with the Very Large Array. During the radio observation, the central X-ray source was partially obscured by a warped disc. We measure a radio flux density of 38.7 ± 4.8 μJy at 9 GHz but cannot constrain the spectral shape. We discuss possible origins of the radio emission, and conclude that coherent emission, a stellar wind, shocks and a propeller outflow are all unlikely explanations. A jet, as seen in LMXBs, is consistent with the observed radio properties. We consider the implications of the presence of a jet in Her X-1 on jet formation mechanisms and on the launching of jets by NSs with strong magnetic fields.

  9. Electronic structure, dielectric response, and surface charge distribution of RGD (1FUV) peptide.

    Science.gov (United States)

    Adhikari, Puja; Wen, Amy M; French, Roger H; Parsegian, V Adrian; Steinmetz, Nicole F; Podgornik, Rudolf; Ching, Wai-Yim

    2014-07-08

    Long and short range molecular interactions govern molecular recognition and self-assembly of biological macromolecules. Microscopic parameters in the theories of these molecular interactions are either phenomenological or need to be calculated within a microscopic theory. We report a unified methodology for the ab initio quantum mechanical (QM) calculation that yields all the microscopic parameters, namely the partial charges as well as the frequency-dependent dielectric response function, that can then be taken as input for macroscopic theories of electrostatic, polar, and van der Waals-London dispersion intermolecular forces. We apply this methodology to obtain the electronic structure of the cyclic tripeptide RGD-4C (1FUV). This ab initio unified methodology yields the relevant parameters entering the long range interactions of biological macromolecules, providing accurate data for the partial charge distribution and the frequency-dependent dielectric response function of this peptide. These microscopic parameters determine the range and strength of the intricate intermolecular interactions between potential docking sites of the RGD-4C ligand and its integrin receptor.

  10. Controlled fabrication of the strong emission YVO{sub 4}:Eu{sup 3+} nanoparticles and nanowires by microwave assisted chemical synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Huong, Tran Thu, E-mail: tthuongims@gmail.com [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Vinh, Le Thi [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Department of Chemistry, Hanoi University of Mining and Geology (Viet Nam); Phuong, Ha Thi [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Department of Chemistry, Hanoi University of Medicine (Viet Nam); Khuyen, Hoang Thi [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Anh, Tran Kim [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Duy Tan University, 14/25 Quang Trung, Da Nang (Viet Nam); Tu, Vu Duc [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Physics, National Chung Cheng University, 168 University Road, Min-Hsiung, Chia-Yi 62102, Taiwan (China); Minh, Le Quoc [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Duy Tan University, 14/25 Quang Trung, Da Nang (Viet Nam)

    2016-05-15

    In this report, we are presenting the controlled fabrication results of the strong emission YVO{sub 4}: Eu{sup 3+} nanoparticles and nanowires by microwave which is assisted chemical synthesis. The effects of incorporated synthesis conditions such as microwave irradiated powers, pH values and concentration of chemical composition on properties of nanomaterials are also investigated to obtain the controllable size and homogenous morphology. Morphological and optical properties of YVO{sub 4}: Eu{sup 3+} prepared products which have been characterized by X-ray diffraction (XRD), field emission micrcroscopy (FESEM) and photoluminescence spectroscopy. As based from result of synthesized samples, we found that the changing of pH values, microwave irradiated powers and chemical composition rise to change reform the size and shape of materials from nanoparticles (diameter about 20 nm) to wires shape (with about 500÷800 nm length and 10÷20 nm width). The photoluminescence (PL) spectroscopy measurements of YVO{sub 4}: Eu{sup 3+} nanostructure materials under UV excitation showed that: the strong luminescence in red region with narrow lines corresponding to the intra-4f transitions of {sup 5}D{sub 0}–{sup 7}F{sub j} (j=1, 2, 3, and 4) of Eu{sup 3+} ions with the highest luminescence intensity of {sup 5}D{sub 0}→{sup 7}F{sub 2} transition. - Highlights: • The strong emission YVO{sub 4}:Eu{sup 3+} nanostructure materials were successfully synthesized by microwave assisted chemical synthesis. • The size, morphology and luminescence of the YVO{sub 4}:Eu{sup 3+} nanostructure materials can be controlled by the solution pH, microwave irradiated powers and chemical composition. • These YVO{sub 4}:Eu{sup 3+} nanostructure materials above can potentially applied in various fields of application, especially in luminescent labeling and visualization in biomedical application.

  11. VERY STRONG EMISSION-LINE GALAXIES IN THE WFC3 INFRARED SPECTROSCOPIC PARALLEL SURVEY AND IMPLICATIONS FOR HIGH-REDSHIFT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Atek, H.; Colbert, J.; Shim, H. [Spitzer Science Center, Caltech, Pasadena, CA 91125 (United States); Siana, B.; Bridge, C. [Department of Astronomy, Caltech, Pasadena, CA 91125 (United States); Scarlata, C. [Department of Astronomy, University of Minnesota-Twin Cities, Minneapolis, MN 55455 (United States); Malkan, M.; Ross, N. R. [Department of Physics and Astronomy, University of California, Los Angeles, CA (United States); McCarthy, P.; Dressler, A.; Hathi, N. P. [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Teplitz, H. [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States); Henry, A.; Martin, C. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Bunker, A. J. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Fosbury, R. A. E. [Space Telescope-European Coordinating Facility, Garching bei Muenchen (Germany)

    2011-12-20

    The WFC3 Infrared Spectroscopic Parallel Survey uses the Hubble Space Telescope (HST) infrared grism capabilities to obtain slitless spectra of thousands of galaxies over a wide redshift range including the peak of star formation history of the universe. We select a population of very strong emission-line galaxies with rest-frame equivalent widths (EWs) higher than 200 A. A total of 176 objects are found over the redshift range 0.35 < z < 2.3 in the 180 arcmin{sup 2} area that we have analyzed so far. This population consists of young and low-mass starbursts with high specific star formation rates (sSFR). After spectroscopic follow-up of one of these galaxies with Keck/Low Resolution Imaging Spectrometer, we report the detection at z = 0.7 of an extremely metal-poor galaxy with 12 + log(O/H) =7.47 {+-} 0.11. After estimating the active galactic nucleus fraction in the sample, we show that the high-EW galaxies have higher sSFR than normal star-forming galaxies at any redshift. We find that the nebular emission lines can substantially affect the total broadband flux density with a median brightening of 0.3 mag, with some examples of line contamination producing brightening of up to 1 mag. We show that the presence of strong emission lines in low-z galaxies can mimic the color-selection criteria used in the z {approx} 8 dropout surveys. In order to effectively remove low-redshift interlopers, deep optical imaging is needed, at least 1 mag deeper than the bands in which the objects are detected. Without deep optical data, most of the interlopers cannot be ruled out in the wide shallow HST imaging surveys. Finally, we empirically demonstrate that strong nebular lines can lead to an overestimation of the mass and the age of galaxies derived from fitting of their spectral energy distribution (SED). Without removing emission lines, the age and the stellar mass estimates are overestimated by a factor of 2 on average and up to a factor of 10 for the high-EW galaxies

  12. THE EFFECTS OF EPISODIC STAR FORMATION ON THE FUV-NUV COLORS OF STAR FORMING REGIONS IN OUTER DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Kate L.; Van Zee, Liese [Department of Astronomy, Indiana University, Bloomington, IN 47405 (United States); Dowell, Jayce D., E-mail: barneskl@astro.indiana.edu, E-mail: vanzee@astro.indiana.edu, E-mail: jdowell@unm.edu [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States)

    2013-09-20

    We run stellar population synthesis models to examine the effects of a recently episodic star formation history (SFH) on UV and Hα colors of star forming regions. Specifically, the SFHs we use are an episodic sampling of an exponentially declining star formation rate (SFR; τ model) and are intended to simulate the SFHs in the outer disks of spiral galaxies. To enable comparison between our models and observational studies of star forming regions in outer disks, we include in our models sensitivity limits that are based on recent deep UV and Hα observations in the literature. We find significant dispersion in the FUV-NUV colors of simulated star forming regions with frequencies of star formation episodes of 1 × 10{sup –8} to 4 × 10{sup –9} yr{sup –1}. The dispersion in UV colors is similar to that found in the outer disk of nearby spiral galaxies. As expected, we also find large variations in L{sub H{sub α}}/L{sub FUV}. We interpret our models within the context of inside-out disk growth, and find that a radially increasing τ and decreasing metallicity with an increasing radius will only produce modest FUV-NUV color gradients, which are significantly smaller than what is found for some nearby spiral galaxies. However, including moderate extinction gradients with our models can better match the observations with steeper UV color gradients. We estimate that the SFR at which the number of stars emitting FUV light becomes stochastic is ∼2 × 10{sup –6} M{sub ☉} yr{sup –1}, which is substantially lower than the SFR of many star forming regions in outer disks. Therefore, we conclude that stochasticity in the upper end of the initial mass function is not likely to be the dominant cause of dispersion in the FUV-NUV colors of star forming regions in outer disks. Finally, we note that if outer disks have had an episodic SFH similar to that used in this study, this should be taken into account when estimating gas depletion timescales and modeling chemical

  13. Charge exchange emission from solar wind helium ions

    NARCIS (Netherlands)

    Bodewits, D; Hoekstra, R; Seredyuk, B; McCullough, RW; Jones, GH; Tielens, AGGM

    2006-01-01

    Charge exchange X-ray and far-ultraviolet (FUV) aurorae can provide detailed insight into the interaction between solar system plasmas. Using the two complementary experimental techniques of photon emission spectroscopy and translation energy spectroscopy, we have studied state-selective charge

  14. Strongly Coupled Tin-Halide Perovskites to Modulate Light Emission: Tunable 550-640 nm Light Emission (FWHM 36-80 nm) with a Quantum Yield of up to 6.4.

    Science.gov (United States)

    Chen, Min-Yi; Lin, Jin-Tai; Hsu, Chia-Shuo; Chang, Chung-Kai; Chiu, Ching-Wen; Chen, Hao Ming; Chou, Pi-Tai

    2018-05-01

    Colloidal perovskite quantum dots represent one of the most promising materials for applications in solar cells and photoluminescences. These devices require a low density of crystal defects and a high yield of photogenerated carriers, which are difficult to realize in tin-halide perovskite because of the intrinsic instability of tin during nucleation. Here, an enhancement in the luminescent property of tin-halide perovskite nanoplates (TPNPs) that are composed of strongly coupled layered structures with the chemical formula of PEA 2 SnX 4 (PEA = C 6 H 5 (CH 2 ) 2 NH 3 , X = Br, I) is reported. TPNPs (X = I) show an emission at a wavelength of 640 nm, with high quantum yield of 6.40 ± 0.14% and full width at half maximum (FWHM) as small as 36 nm. The presence of aliphatic carboxylic acid is found to play a key role in reducing the tin perovskite defect density, which significantly improves the emission intensity and stability of TPNPs. Upon mixing iodo- and bromo- precursors, the emission wavelength is successfully tuned from 640 nm (PEA 2 SnI 4 ) to 550 nm (PEA 2 SnBr 4 ), with a corresponding emission quantum yield and FWHM of 0.16-6.40% and 36-80 nm, respectively. The results demonstrate a major advance for the emission yield and tunability of tin-halide perovskites. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Effects of neutrino emissivity on the cooling of neutron stars in the presence of a strong magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Eduardo Lenho, E-mail: eduardo.coelho@uva.br [Universidade Veiga de Almeida, 108 Ibituruna St., 20271-020, Rio de Janeiro (Brazil); Chiapparini, Marcelo [Instituto de Física, Universidade do Estado do Rio de Janeiro, 524 São Francisco Xavier St., 20271-020, Rio de Janeiro (Brazil); Negreiros, Rodrigo Picanço [Instituto de Física, Universidade Federal Fluminense, Gal. Milton Tavares de Souza Ave., 24210-346, Rio de Janeiro (Brazil)

    2015-12-17

    One of the most interesting kind of neutron stars are the pulsars, which are highly magnetized neutron stars with fields up to 10{sup 14} G at the surface. The strength of magnetic field in the center of a neutron star remains unknown. According to the scalar virial theorem, magnetic field in the core could be as large as 10{sup 18} G. In this work we study the influence of strong magnetic fields on the cooling of neutron stars coming from direct Urca process. Direct Urca process is an extremely efficient mechanism for cooling a neutron star after its formation. The matter is described using a relativistic mean-field model at zero temperature with eight baryons (baryon octet), electrons and muons. We obtain the relative population of each species of particles as function of baryon density for different magnetic fields. We calculate numerically the cooling of neutron stars for a parametrized magnetic field and compare the results for the case without a magnetic field.

  16. SUZAKU OBSERVATION OF STRONG FLUORESCENT IRON LINE EMISSION FROM THE YOUNG STELLAR OBJECT V1647 ORI DURING ITS NEW X-RAY OUTBURST

    International Nuclear Information System (INIS)

    Hamaguchi, Kenji; Grosso, Nicolas; Kastner, Joel H.; Richmond, Michael; Weintraub, David A.

    2010-01-01

    The Suzaku X-ray satellite observed the young stellar object (YSO) V1647 Ori on 2008 October 8 during the new mass accretion outburst reported in 2008 August. During the 87 ks observation with a net exposure of 40 ks, V1647 Ori showed a high level of X-ray emission with a gradual decrease in flux by a factor of 5 and then displayed an abrupt flux increase by an order of magnitude. Such enhanced X-ray variability was also seen in XMM-Newton observations in 2004 and 2005 during the 2003-2005 outburst, but has rarely been observed for other YSOs. The spectrum clearly displays emission from Helium-like iron, which is a signature of hot plasma (kT ∼ 5 keV). It also shows a fluorescent iron Kα line with a remarkably large equivalent width (EW) of ∼600 eV. Such a large EW suggests that a part of the incident X-ray emission that irradiates the circumstellar material and/or the stellar surface is hidden from our line of sight. XMM-Newton spectra during the 2003-2005 outburst did not show a strong fluorescent iron Kα line, so that the structure of the circumstellar gas very close to the stellar core that absorbs and re-emits X-ray emission from the central object may have changed in between 2005 and 2008. This phenomenon may be related to changes in the infrared morphology of McNeil's nebula between 2004 and 2008.

  17. DISCOVERY OF C IV EMISSION FILAMENTS IN M87

    International Nuclear Information System (INIS)

    Sparks, W. B.; Pringle, J. E.; Cracraft, M.; Donahue, M.; Voit, M.; Carswell, R.; Martin, R. G.

    2009-01-01

    Gas at intermediate temperatures between the hot X-ray-emitting coronal gas in galaxies at the centers of galaxy clusters and the much cooler optical line emitting filaments yields information on transport processes and plausible scenarios for the relationship between X-ray cool cores and other galactic phenomena such as mergers or the onset of an active galactic nucleus. Hitherto, detection of intermediate temperature gas has proven elusive. Here, we present FUV imaging of the 'low excitation' emission filaments of M87 and show strong evidence for the presence of C IV 1549 A emission which arises in gas at temperature ∼10 5 K co-located with Hα+[N II] emission from cooler ∼10 4 K gas. We infer that the hot and cool phases are in thermal communication, and show that quantitatively the emission strength is consistent with thermal conduction, which in turn may account for many of the observed characteristics of cool-core galaxy clusters.

  18. THE REST-FRAME OPTICAL SPECTROSCOPIC PROPERTIES OF LY α -EMITTERS AT z  ∼ 2.5: THE PHYSICAL ORIGINS OF STRONG LY α EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Trainor, Ryan F. [Department of Astronomy, University of California, Berkeley, 501 Campbell Hall, Berkeley, CA 94720 (United States); Strom, Allison L.; Steidel, Charles C. [Cahill Center for Astrophysics, MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125 (United States); Rudie, Gwen C., E-mail: trainor@berkeley.edu [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

    2016-12-01

    We present the rest-frame optical spectroscopic properties of 60 faint ( R {sub AB} ∼ 27; L ∼ 0.1 L {sub *}) Ly α -selected galaxies (LAEs) at z  ≈ 2.56. These LAEs also have rest-UV spectra of their Ly α emission line morphologies, which trace the effects of interstellar and circumgalactic gas on the escape of Ly α photons. We find that the LAEs have diverse rest-optical spectra, but their average spectroscopic properties are broadly consistent with the extreme low-metallicity end of the populations of continuum-selected galaxies selected at z  ≈ 2–3. In particular, the LAEs have extremely high [O iii] λ 5008/H β ratios (log([O iii]/H β ) ∼ 0.8) and low [N ii] λ 6585/H α ratios (log([N ii]/H α ) < 1.15). Coupled with a detection of the [O iii] λ 4364 auroral line, these measurements indicate that the star-forming regions in faint LAEs are characterized by high electron temperatures (T{sub e} ≈ 1.8 × 10{sup 4} K), low oxygen abundances (12 + log(O/H) ≈ 8.04, Z{sub neb} ≈ 0.22 Z {sub ⊙}), and high excitations with respect to their more luminous continuum-selected analogs. Several of our faintest LAEs have line ratios consistent with even lower metallicities, including six with 12 + log(O/H) ≈ 6.9–7.4 (Z {sub neb} ≈ 0.02–0.05 Z{sub ⊙}). We interpret these observations in light of new models of stellar evolution (including binary interactions) that have been shown to produce long-lived populations of hot, massive stars at low metallicities. We find that strong, hard ionizing continua are required to reproduce our observed line ratios, suggesting that faint galaxies are efficient producers of ionizing photons and important analogs of reionization-era galaxies. Furthermore, we investigate the physical trends accompanying Ly α emission across the largest current sample of combined Ly α and rest-optical galaxy spectroscopy, including both the 60 KBSS-Ly α LAEs and 368 more luminous galaxies at similar redshifts. We

  19. Time-resolved pulse-counting lock-in detection of laser induced fluorescence in the presence of a strong background emission

    International Nuclear Information System (INIS)

    Pelissier, B.; Sadeghi, N.

    1996-01-01

    We describe a time-resolved pulse-counting system well adapted for the detection of continuous laser induced fluorescence (LIF) signals in repetitive phenomena, when a strong background emission is present. It consists of 256 channels coupled to a first in first out memory and interfaced to a 486 DX 33 PC, for data storage. It accepts time-averaged count rates up to 450 kcount/s. Time between channels can be set from 12.5 ns to several μs and the dead time between two consecutive cycles of the physical phenomena is less than 20 ns. In phase with a chopper, which modulates the laser beam, it adds the observed photon signal to the channel memories when the beam is on and substracts it when the beam is stopped, acting like a lock-in amplifier which detect only the modulated part of the signal. The minimum detectivity on the LIF signal is only limited by the shot noise of the plasma induced emission signal. As an application, we studied the time variation of the Ar + *( 2 G 9/2 ) metastable ions, detected by LIF, in two types of plasmas. Their radiative lifetime and collisional quenching frequencies were deduced from their decay rate in the afterglow of a pulsed Helicon reactor. We also observed the evolution of their density in a 455 kHz capacitively coupled argon discharge. copyright 1996 American Institute of Physics

  20. Time-resolved pulse-counting lock-in detection of laser induced fluorescence in the presence of a strong background emission

    Science.gov (United States)

    Pelissier, B.; Sadeghi, N.

    1996-10-01

    We describe a time-resolved pulse-counting system well adapted for the detection of continuous laser induced fluorescence (LIF) signals in repetitive phenomena, when a strong background emission is present. It consists of 256 channels coupled to a first in first out memory and interfaced to a 486 DX 33 PC, for data storage. It accepts time-averaged count rates up to 450 kcount/s. Time between channels can be set from 12.5 ns to several μs and the dead time between two consecutive cycles of the physical phenomena is less than 20 ns. In phase with a chopper, which modulates the laser beam, it adds the observed photon signal to the channel memories when the beam is on and substracts it when the beam is stopped, acting like a lock-in amplifier which detect only the modulated part of the signal. The minimum detectivity on the LIF signal is only limited by the shot noise of the plasma induced emission signal. As an application, we studied the time variation of the Ar+*(2G9/2) metastable ions, detected by LIF, in two types of plasmas. Their radiative lifetime and collisional quenching frequencies were deduced from their decay rate in the afterglow of a pulsed Helicon reactor. We also observed the evolution of their density in a 455 kHz capacitively coupled argon discharge.

  1. Estimates of magnetotail reconnection rate based on IMAGE FUV and EISCAT measurements

    Directory of Open Access Journals (Sweden)

    N. Østgaard

    2005-01-01

    Full Text Available Dayside merging between the interplanetary and terrestrial magnetic fields couples the solar wind electric field to the Earth's magnetosphere, increases the magnetospheric convection and results in efficient transport of solar wind energy into the magnetosphere. Subsequent reconnection of the lobe magnetic field in the magnetotail transports energy into the closed magnetic field region. Combining global imaging and ground-based radar measurements, we estimate the reconnection rate in the magnetotail during two days of an EISCAT campaign in November-December 2000. Global images from the IMAGE FUV system guide us to identify ionospheric signatures of the open-closed field line boundary observed by the two EISCAT radars in Tromsø (VHF and on Svalbard (ESR. Continuous radar and optical monitoring of the open-closed field line boundary is used to determine the location, orientation and velocity of the open-closed boundary and the ion flow velocity perpendicular to this boundary. The magnetotail reconnection electric field is found to be a bursty process that oscillates between 0mV/m and 1mV/m with ~10-15min periods. These ULF oscillations are mainly due to the motion of the open-closed boundary. In situ measurements earthward of the reconnection site in the magnetotail by Geotail show similar oscillations in the duskward electric field. We also find that bursts of increased magnetotail reconnection do not necessarily have any associated auroral signatures. Finally, we find that the reconnection rate correlates poorly with the solar wind electric field. This indicates that the magnetotail reconnection is not directly driven, but is an internal magnetospheric process. Estimates of a coupling efficiency between the solar wind electric field and magnetotail reconnection only seem to be relevant as averages over long time intervals. The oscillation mode at 1mHz corresponds to the internal cavity mode with additional lower frequencies, 0.5 and 0.8m

  2. [C II] and {sup 12}CO(1-0) emission maps in HLSJ091828.6+514223: A strongly lensed interacting system at z = 5.24

    Energy Technology Data Exchange (ETDEWEB)

    Rawle, T. D.; Altieri, B. [ESAC, ESA, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid (Spain); Egami, E.; Rex, M.; Clement, B. [Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States); Bussmann, R. S.; Gurwell, M.; Fazio, G. G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ivison, R. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Boone, F. [Université de Toulouse, UPS-OMP, CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); Combes, F. [Observatoire de Paris, LERMA, CNRS, 61 Av. de l' Observatoire, F-75014 Paris (France); Danielson, A. L. R.; Smail, I.; Swinbank, A. M.; Edge, A. C. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Richard, J. [CRAL, Université Lyon-1, 9 Av. Charles Andr, F-69561 St Genis Laval (France); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Dessauges-Zavadsky, M. [Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290, Sauverny (Switzerland); Jones, T. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Kneib, J.-P., E-mail: tim.rawle@sciops.esa.int [Laboratoire d' Astrophysique EPFL, Observatoire de Sauverny, Versoix 1290 (Switzerland); and others

    2014-03-01

    We present Submillimeter Array [C II] 158 μm and Karl G. Jansky Very Large Array {sup 12}CO(1-0) line emission maps for the bright, lensed, submillimeter source at z = 5.2430 behind A 773: HLSJ091828.6+514223 (HLS0918). We combine these measurements with previously reported line profiles, including multiple {sup 12}CO rotational transitions, [C I], water, and [N II], providing some of the best constraints on the properties of the interstellar medium in a galaxy at z > 5. HLS0918 has a total far-infrared (FIR) luminosity L {sub FIR(8–1000} {sub μm)} = (1.6 ± 0.1) × 10{sup 14} L {sub ☉} μ{sup –1}, where the total magnification μ{sub total} = 8.9 ± 1.9, via a new lens model from the [C II] and continuum maps. Despite a HyLIRG luminosity, the FIR continuum shape resembles that of a local LIRG. We simultaneously fit all of the observed spectral line profiles, finding four components that correspond cleanly to discrete spatial structures identified in the maps. The two most redshifted spectral components occupy the nucleus of a massive galaxy, with a source-plane separation <1 kpc. The reddest dominates the continuum map (demagnified L {sub FIR,} {sub component} = (1.1 ± 0.2) × 10{sup 13} L {sub ☉}) and excites strong water emission in both nuclear components via a powerful FIR radiation field from the intense star formation. A third star-forming component is most likely a region of a merging companion (ΔV ∼ 500 km s{sup –1}) exhibiting generally similar gas properties. The bluest component originates from a spatially distinct region and photodissociation region analysis suggests that it is lower density, cooler, and forming stars less vigorously than the other components. Strikingly, it has very strong [N II] emission, which may suggest an ionized, molecular outflow. This comprehensive view of gas properties and morphology in HLS0918 previews the science possible for a large sample of high-redshift galaxies once ALMA attains full sensitivity.

  3. (F)UV Spectral Analysis of 15 Hot, Hydrogen-Rich Central Stars of PNe

    Science.gov (United States)

    Ziegler, Marc

    2013-07-01

    The aim of this thesis was the precise determination of basic stellar parameters and metal abundances for a sample of 15 ionizing stars of gaseous nebulae. Strategic lines of metals for the expected parameter range are located in the ultraviolet (UV) and far-ultraviolet (FUV) range. Thus high-resolution, high-S/N UV and FUV observations obtained with the Hubble Space Telescope (HST) and the Far Ultraviolet Spectroscopic Explorer (FUSE) were used for the analysis. For the calculation of the necessary spectral energy distributions the Tübingen NLTE Model-Atmosphere Package (TMAP) was used. The model atmospheres included most elements from H - Ni in order to account for line-blanketing effects. For each object a small grid of model atmospheres was calculated. As the interstellar medium (ISM) imprints its influence in the Space Telescope Imaging Spectrograph (STIS) and especially the FUSE range, the program OWENS was employed to calculate the interstellar absorption features. Both, the photospheric model spectral energy distribution (SED) as well as the ISM models were combined to enable the identification of most of the observed absorption lines. The analyzed sample covers a range of 70 kK < Teff < 136 kK, and surface gravities from log (g/cm/sec^2) = 5.4 - 7.4, thus representing different stages of stellar evolution. For a large number of elements, abundances were determined for the first time in these objects. Lines of C, N, O, F, Ne, Si, P, S, and Ar allowed to determine the corresponding abundances. For none of the objects lines of Ca, Sc, Ti, and V could be found. Only a few objects were rich in Cr, Mn, Fe, Co, and Ni lines. Most of the analyzed stars exhibited only lines of Fe (ionization stages V - VIII) from the iron-group elements. No signs for gravitational settling (the gravitational force exceeds the radiation pressure and elements begin to sink from the atmosphere into deeper layers) were found. This is expected as the values of the surface gravities of

  4. On the use of IMAGE FUV for estimating the latitude of the open/closed magnetic field line boundary in the ionosphere

    Directory of Open Access Journals (Sweden)

    P. D. Boakes

    2008-09-01

    Full Text Available A statistical comparison of the latitude of the open/closed magnetic field line boundary (OCB as estimated from the three far ultraviolet (FUV detectors onboard the IMAGE spacecraft (the Wideband Imaging camera, WIC, and the Spectrographic Imagers, SI-12 and SI-13 has been carried out over all magnetic local times. A total of over 400 000 OCB estimations were compared from December 2000 and January and December of 2001–2002. The modal latitude difference between the FUV OCB proxies from the three detectors is small, <1°, except in the predawn and evening sectors, where the SI-12 OCB proxy is found to be displaced from both the SI-13 and WIC OCB proxies by up to 2° poleward in the predawn sector and by up to 2° equatorward in the evening sector. Comparing the IMAGE FUV OCB proxies with that determined from particle precipitation measurements by the Defense Meteorological Satellites Program (DMSP also shows systematic differences. The SI-12 OCB proxy is found to be at higher latitude in the predawn sector, in better agreement with the DMSP OCB proxy. The WIC and SI-13 OCB proxies are found to be in better agreement with the DMSP OCB proxy at most other magnetic local times. These systematic offsets may be used to correct FUV OCB proxies to give a more accurate estimate of the OCB latitude.

  5. Complex organic molecules in strongly UV-irradiated gas

    Science.gov (United States)

    Cuadrado, S.; Goicoechea, J. R.; Cernicharo, J.; Fuente, A.; Pety, J.; Tercero, B.

    2017-07-01

    We investigate the presence of complex organic molecules (COMs) in strongly UV-irradiated interstellar molecular gas. We have carried out a complete millimetre (mm) line survey using the IRAM 30 m telescope towards the edge of the Orion Bar photodissociation region (PDR), close to the H2 dissociation front, a position irradiated by a very intense far-UV (FUV) radiation field. These observations have been complemented with 8.5'' resolution maps of the H2CO JKa,Kc = 51,5 → 41,4 and C18O J = 3 → 2 emission at 0.9 mm. Despite being a harsh environment, we detect more than 250 lines from COMs and related precursors: H2CO, CH3OH, HCO, H2CCO, CH3CHO, H2CS, HCOOH, CH3CN, CH2NH, HNCO, H213CO, and HC3N (in decreasing order of abundance). For each species, the large number of detected lines allowed us to accurately constrain their rotational temperatures (Trot) and column densities (N). Owing to subthermal excitation and intricate spectroscopy of some COMs (symmetric- and asymmetric-top molecules such as CH3CN and H2CO, respectively), a correct determination of N and Trot requires building rotational population diagrams of their rotational ladders separately. The inferred column densities are in the 1011-1013 cm-2 range. We also provide accurate upper limit abundances for chemically related molecules that might have been expected, but are not conclusively detected at the edge of the PDR (HDCO, CH3O, CH3NC, CH3CCH, CH3OCH3, HCOOCH3, CH3CH2OH, CH3CH2CN, and CH2CHCN). A non-thermodynamic equilibrium excitation analysis for molecules with known collisional rate coefficients suggests that some COMs arise from different PDR layers but we cannot resolve them spatially. In particular, H2CO and CH3CN survive in the extended gas directly exposed to the strong FUV flux (Tk = 150-250 K and Td≳ 60 K), whereas CH3OH only arises from denser and cooler gas clumps in the more shielded PDR interior (Tk = 40-50 K). The non-detection of HDCO towards the PDR edge is consistent with the

  6. Strong red-emission of Eu{sup 3+}:Li{sub 4}Ti{sub 5}O{sub 12} powders for phosphor applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yan [Kazuo Inamori School of Engineering, New York State College of Ceramics, Alfred University, Alfred, NY 14802 (United States); Jiménez, José A. [Department of Chemistry, University of North Florida, Jacksonville, FL 32224 (United States); Wu, Yiquan, E-mail: wuy@alfred.edu [Kazuo Inamori School of Engineering, New York State College of Ceramics, Alfred University, Alfred, NY 14802 (United States)

    2016-08-15

    The synthesis and photoluminescence properties of trivalent europium doped lithium titanate (Eu{sup 3+}:Li{sub 4}Ti{sub 5}O{sub 12}) with different Eu{sup 3+} concentrations (0.1 mol%, 0.3 mol%, 1.0 mol%, 3.0 mol%) are reported and analyzed as a phosphor. Europium (III) nitrate (Eu(NO{sub 3}){sub 3}) was employed as Eu{sup 3+} source, while lithium acetate dihydrate (CH{sub 3}COOLi·2H{sub 2}O) and titanium n-butoxide (Ti(OC{sub 4}H{sub 9}){sub 4}) were adopted as raw materials to synthesize the host lithium titanate with a Li:Ti stoichiometry of 4.5:1. Phase identification was performed using X-ray diffraction (XRD), and morphology was examined using scanning electron microscopy (SEM). Eu{sup 3+}:Li{sub 4}Ti{sub 5}O{sub 12} powders showed strong red emission at 612 nm, corresponding to the {sup 5}D{sub 0}–{sup 7}F{sub 2} transition, with the strongest excitation peak observed in the blue light region at 464 nm. Decay time analyses revealed relatively short lifetimes accompanying typical exponential decay rates. The effect of Eu{sup 3+} concentration (0.1 mol%, 0.3 mol%, 1.0 mol%, 3.0 mol%) on photoluminescence intensity and decay time was explored, and is reported here. It was determined that the CIE color coordinates (0.66, 0.34) of the doped Li{sub 4}Ti{sub 5}O{sub 12} powders were independent of Eu{sup 3+} concentration, and that the coordinates are very similar to the ideal red chromaticity (0.67, 0.33) designated by the National Television Standard Committee (NTSC) system.

  7. Absorption and Emission of EUV Radiation by the Local ISM

    Science.gov (United States)

    Paresce, F.

    1984-01-01

    The Berkeley extreme ultraviolet radiation (EUV) telescope flown on the Apollo Soyuz mission in July, 1975 established the existence of a measurable flux of EUV (100 lambda or = or = 1000 A) originating from sources outside the solar system. White dwarfs, flare stars and cataclysmic variables were dicovered to be relatively intense compact sources of EUV photons. Moreover, this and other subsequent experiments have strongly suggested the presence of a truly diffuse component of the FUV radiation field possibly due to thermal emission from hot interstellar gas located in the general vicinity of the Sun. Closer to the H1, 912 A edge, the effect of a few hot O and B stars has been shown to be very important in establishing the interstellar flux density. All these results imply that the local interstellar medium (ISM) is immersed in a non-negligible EUV radiation field which, because of the strong coupling between EUV photons and matter, will play a crucial role in determining its physical structure. The available information on the local ISM derived from the limited EUV observations carried out so far is assembled and analyzed. These include measurements of the spectra of bright EUV sources that reveal clear evidence of H photo absorption at lambda 400 A and of the He ionization edge at 228 A.

  8. THE BURSTY STAR FORMATION HISTORIES OF LOW-MASS GALAXIES AT 0.4 < z < 1 REVEALED BY STAR FORMATION RATES MEASURED FROM H β AND FUV

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yicheng; Faber, S. M.; Koo, David C.; Krumholz, Mark R.; Barro, Guillermo; Yesuf, Hassen [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States); Rafelski, Marc; Gardner, Jonathan P.; Pacifici, Camilla [Goddard Space Flight Center, Code 665, Greenbelt, MD (United States); Trump, Jonathan R. [Department of Astronomy and Astrophysics and Institute for Gravitation and the Cosmos, Pennsylvania State University, University Park, PA (United States); Willner, S. P. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Amorín, Ricardo [INAF-Osservatorio Astronomico di Roma, Monte Porzio Catone (Italy); Bell, Eric F. [Department of Astronomy, University of Michigan, Ann Arbor, MI (United States); Gawiser, Eric [Department of Physics and Astronomy, Rutgers University, New Brunswick, NJ (United States); Hathi, Nimish P. [Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, Marseille (France); Koekemoer, Anton M.; Ravindranath, Swara [Space Telescope Science Institute, Baltimore, MD (United States); Pérez-González, Pablo G. [Departamento de Astrofísica, Facultad de CC. Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Reddy, Naveen [Department of Physics and Astronomy, University of California, Riverside, CA (United States); Teplitz, Harry I., E-mail: ycguo@ucolick.org [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States)

    2016-12-10

    We investigate the burstiness of star formation histories (SFHs) of galaxies at 0.4 <  z  < 1 by using the ratio of star formation rates (SFRs) measured from H β and FUV (1500 Å) (H β -to-FUV ratio). Our sample contains 164 galaxies down to stellar mass ( M {sub *}) of 10{sup 8.5} M {sub ⊙} in the CANDELS GOODS-N region, where Team Keck Redshift Survey Keck/DEIMOS spectroscopy and Hubble Space Telescope /WFC3 F275W images from CANDELS and Hubble Deep UV Legacy Survey are available. When the ratio of H β - and FUV-derived SFRs is measured, dust extinction correction is negligible (except for very dusty galaxies) with the Calzetti attenuation curve. The H β -to-FUV ratio of our sample increases with M {sub *} and SFR. The median ratio is ∼0.7 at M {sub *} ∼ 10{sup 8.5} M {sub ⊙} (or SFR ∼ 0.5 M {sub ⊙} yr{sup −1}) and increases to ∼1 at M {sub *} ∼ 10{sup 10} M {sub ⊙} (or SFR ∼ 10 M {sub ⊙} yr{sup −1}). At M {sub *} < 10{sup 9.5} M {sub ⊙}, our median H β -to-FUV ratio is lower than that of local galaxies at the same M {sub *}, implying a redshift evolution. Bursty SFH on a timescale of a few tens of megayears on galactic scales provides a plausible explanation for our results, and the importance of the burstiness increases as M {sub *} decreases. Due to sample selection effects, our H β -to-FUV ratio may be an upper limit of the true value of a complete sample, which strengthens our conclusions. Other models, e.g., non-universal initial mass function or stochastic star formation on star cluster scales, are unable to plausibly explain our results.

  9. IMF control of cusp proton emission intensity and dayside convection: implications for component and anti-parallel reconnection

    Directory of Open Access Journals (Sweden)

    M. Lockwood

    2003-04-01

    Full Text Available We study a brightening of the Lyman-a emission in the cusp which occurred in response to a short-lived south-ward turning of the interplanetary magnetic field (IMF during a period of strongly enhanced solar wind plasma concentration. The cusp proton emission is detected using the SI-12 channel of the FUV imager on the IMAGE spacecraft. Analysis of the IMF observations recorded by the ACE and Wind spacecraft reveals that the assumption of a constant propagation lag from the upstream spacecraft to the Earth is not adequate for these high time-resolution studies. The variations of the southward IMF component observed by ACE and Wind allow for the calculation of the ACE-to-Earth lag as a function of time. Application of the derived propagation delays reveals that the intensity of the cusp emission varied systematically with the IMF clock angle, the relationship being particularly striking when the intensity is normalised to allow for the variation in the upstream solar wind proton concentration. The latitude of the cusp migrated equatorward while the lagged IMF pointed southward, confirming the lag calculation and indicating ongoing magnetopause reconnection. Dayside convection, as monitored by the SuperDARN network of radars, responded rapidly to the IMF changes but lagged behind the cusp proton emission response: this is shown to be as predicted by the model of flow excitation by Cowley and Lockwood (1992. We use the numerical cusp ion precipitation model of Lockwood and Davis (1996, along with modelled Lyman-a emission efficiency and the SI-12 instrument response, to investigate the effect of the sheath field clock angle on the acceleration of ions on crossing the dayside magnetopause. This modelling reveals that the emission commences on each reconnected field line 2–2.5 min after it is opened and peaks 3–5 min after it is opened. We discuss how comparison of the Lyman-a intensities with oxygen emissions observed simultaneously by the SI-13

  10. IMF control of cusp proton emission intensity and dayside convection: implications for component and anti-parallel reconnection

    Directory of Open Access Journals (Sweden)

    M. Lockwood

    Full Text Available We study a brightening of the Lyman-a emission in the cusp which occurred in response to a short-lived south-ward turning of the interplanetary magnetic field (IMF during a period of strongly enhanced solar wind plasma concentration. The cusp proton emission is detected using the SI-12 channel of the FUV imager on the IMAGE spacecraft. Analysis of the IMF observations recorded by the ACE and Wind spacecraft reveals that the assumption of a constant propagation lag from the upstream spacecraft to the Earth is not adequate for these high time-resolution studies. The variations of the southward IMF component observed by ACE and Wind allow for the calculation of the ACE-to-Earth lag as a function of time. Application of the derived propagation delays reveals that the intensity of the cusp emission varied systematically with the IMF clock angle, the relationship being particularly striking when the intensity is normalised to allow for the variation in the upstream solar wind proton concentration. The latitude of the cusp migrated equatorward while the lagged IMF pointed southward, confirming the lag calculation and indicating ongoing magnetopause reconnection. Dayside convection, as monitored by the SuperDARN network of radars, responded rapidly to the IMF changes but lagged behind the cusp proton emission response: this is shown to be as predicted by the model of flow excitation by Cowley and Lockwood (1992. We use the numerical cusp ion precipitation model of Lockwood and Davis (1996, along with modelled Lyman-a emission efficiency and the SI-12 instrument response, to investigate the effect of the sheath field clock angle on the acceleration of ions on crossing the dayside magnetopause. This modelling reveals that the emission commences on each reconnected field line 2–2.5 min after it is opened and peaks 3–5 min after it is opened. We discuss how comparison of the Lyman-

  11. A Far-ultraviolet Fluorescent Molecular Hydrogen Emission Map of the Milky Way Galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Young-Soo; Min, Kyoung-Wook [Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Seon, Kwang-Il; Han, Wonyong [Korea Astronomy and Space Science Institute (KASI), 776 Daedeokdae-ro, Yuseong-gu, Daejeon, 305-348 (Korea, Republic of); Edelstein, Jerry, E-mail: stspeak@gmail.com [Space Sciences Laboratory, University of California, Berkeley, CA, 94720 (United States)

    2017-08-01

    We present the far-ultraviolet (FUV) fluorescent molecular hydrogen (H{sub 2}) emission map of the Milky Way Galaxy obtained with FIMS/SPEAR covering ∼76% of the sky. The extinction-corrected intensity of the fluorescent H{sub 2} emission has a strong linear correlation with the well-known tracers of the cold interstellar medium (ISM), including color excess E(B–V) , neutral hydrogen column density N (H i), and H α emission. The all-sky H{sub 2} column density map was also obtained using a simple photodissociation region model and interstellar radiation fields derived from UV star catalogs. We estimated the fraction of H{sub 2} ( f {sub H2}) and the gas-to-dust ratio (GDR) of the diffuse ISM. The f {sub H2} gradually increases from <1% at optically thin regions where E(B–V) < 0.1 to ∼50% for E(B–V)  = 3. The estimated GDR is ∼5.1 × 10{sup 21} atoms cm{sup −2} mag{sup −1}, in agreement with the standard value of 5.8 × 10{sup 21} atoms cm{sup −2} mag{sup −1}.

  12. Influence of local emissions on concentration and isotopic composition of trace gases (CO2 and CH4) under strong anthropopression: A case study from Krakow, southern Poland

    International Nuclear Information System (INIS)

    Florkowski, T.; Korus, A.; Kuc, T.; Lasa, J.; Necki, J.M.; Zimnoch, M.

    2002-01-01

    Full text: Measurements of the isotopic composition of carbon dioxide and methane together with their concentrations in the atmosphere, yield useful information on the contribution of anthropogenic sources to regional budgets of these gases and their seasonal changes. Observed correlation between isotopic composition and inverse concentration of these gases is used for estimation of mean isotopic composition of the local source. Monitoring of atmospheric CO 2 has been initiated in Krakow in 1982. The sampling point is located in a polluted urban area with strong contribution of anthropogenic gases originating both from local sources (coal burning, car traffic, leakages from city gas network, landfills) and large distant emitters - industrial district located ca. 80 km to the west from Krakow (Silesia district). Quasi-continuous measurements of CO 2 , and CH 4 concentrations in the low atmosphere are performed using gas chromatographic method. For isotope measurements, the atmospheric CO 2 is continuously sampled by sorption on molecular sieve in be-weekly intervals and radiocarbon concentration is measured by liquid scintillation spectrometer, while δ 13 C is determined by isotope ratio mass spectrometer. Measurement error (1σ for single measurement) is in the order of 0.1 ppm for CO 2 concentration, ±8 per mille for δ 14 C, and ± 0.1 per mille for δ 13 C. In 1994, a new station for regular observations of greenhouse gases in lower atmosphere was set up in the High Tatra mountains, at Kasprowy Wierch (49 deg. N, 20 deg. E, 1980 m a.s.l., 300 m above the tree line). Kasprowy Wierch, with only small influences from local sources of trace gases can be considered as a reference station for this region of Poland. The record of CO 2 and CH 4 concentration and their isotope composition obtained at Kasprowy Wierch is considered as a background level for Krakow observations. The presented study was aimed at better characterisation and quantification of the local

  13. Strong γ-ray emission from neutron unbound states populated in β-decay: Impact on (n,γ) cross-section estimates

    International Nuclear Information System (INIS)

    Tain, J. L.; Guadilla, V.; Valencia, E.; Algora, A.

    2017-01-01

    Total absorption gamma-ray spectroscopy is used to measure accurately the intensity of γ emission from neutron-unbound states populated in the β-decay of delayed-neutron emitters. From the comparison of this intensity with the intensity of neutron emission one can deduce information on the (n,γ) cross section for unstable neutron-rich nuclei of interest in r process abundance calculations. A surprisingly large γ branching was observed for a number of isotopes. Here, the results are compared with Hauser-Feshbach calculations and discussed.

  14. FTIR and Vis-FUV real time spectroscopic ellipsometry studies of polymer surface modifications during ion beam bombardment

    Science.gov (United States)

    Laskarakis, A.; Gravalidis, C.; Logothetidis, S.

    2004-02-01

    The continuously increasing application of polymeric materials in many scientific and technological fields has motivated an extensive use of polymer surface treatments, which modify the physical and chemical properties of polymer surfaces leading to surface activation and promotion of the surface adhesion. Fourier transform IR spectroscopic ellipsometry (FTIRSE) and phase modulated ellipsometry (PME) in the IR and Vis-FUV spectral regions respectively have been employed for in situ and real time monitoring of the structural changes on the polymer surface obtained by Ar + ion bombardment. The polymers were industrially supplied polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) membranes. The Ar + ion bombardment has found to change the chemical bonding of the films and especially the amount of the CO, C-C and CC groups. The detailed study of the FTIRSE spectra reveals important information about the effect of the Ar + ion bombardment on each of the above bonding groups. Also, the modification of the characteristic features, attributed to electronic transitions in specific bonds of PET and PEN macromolecules, has been studied using PME.

  15. FTIR and Vis-FUV real time spectroscopic ellipsometry studies of polymer surface modifications during ion beam bombardment

    International Nuclear Information System (INIS)

    Laskarakis, A.; Gravalidis, C.; Logothetidis, S.

    2004-01-01

    The continuously increasing application of polymeric materials in many scientific and technological fields has motivated an extensive use of polymer surface treatments, which modify the physical and chemical properties of polymer surfaces leading to surface activation and promotion of the surface adhesion. Fourier transform IR spectroscopic ellipsometry (FTIRSE) and phase modulated ellipsometry (PME) in the IR and Vis-FUV spectral regions respectively have been employed for in situ and real time monitoring of the structural changes on the polymer surface obtained by Ar + ion bombardment. The polymers were industrially supplied polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) membranes. The Ar + ion bombardment has found to change the chemical bonding of the films and especially the amount of the C-O, C-C and C-C groups. The detailed study of the FTIRSE spectra reveals important information about the effect of the Ar + ion bombardment on each of the above bonding groups. Also, the modification of the characteristic features, attributed to electronic transitions in specific bonds of PET and PEN macromolecules, has been studied using PME

  16. Those Crafty Cepheids: Surprises From Ground-Based Photometry and HST-COS FUV Spectra

    Science.gov (United States)

    Engle, Scott G.; Guinan, E. F.; Neilson, H.; Wasatonic, R. P.; Harper, G.

    2013-06-01

    Several years ago the Secret Lives of Cepheids (SLiC) program was initiated to look for unexpected or exotic behaviors from Cepheids. Regular photometric monitoring of Cepheids already possessing robust historical datasets was started to better understand long-term pulsation period changes, but to look for possible amplitude changes as well. At the time, only two “unusual” Cepheids were known to have undergone amplitude changes - Polaris and V473 Lyr. To date, however, the SLiC program has found evidence for amplitude changes in seven other Cepheids, raising the possibility that a "Blazhko effect" could be at work in certain Cepheids, as exists in a subset of RR Lyr stars. As the program expanded, we found that previous International Ultraviolet Exporer (IUE) studies showed certain Cepheids to have UV emissions from warm-to-hot stellar atmospheres. On top of that, the emissions were variable and well-phased to the stellar pulsation period, indicating that the mechanism heating the Cepheid atmosphere was influenced by these pulsations, if not linked to them. With the installation of the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope (HST), a modern, high-quality UV spectrograph was now operating that could efficiently obtain high-resolution spectra of the Cepheids. We have been fortunate to observe four Cepheids to date with COS, and the results are well beyond anything IUE had led us to expect. Here we will present the current optical and UV results of the SLiC program, the implications of the results, and the future direction and expansion of the program. We gratefully acknowledge support for this program from HST grants HST-GO-11726.01-A, HST-GO-12302.01-A and HST-GO-13019.01-A, as well as NSF/RUI grant AST-1009903.

  17. A simulation study of a method to reduce positron annihilation spread distributions using a strong magnetic field in positron emission tomography

    International Nuclear Information System (INIS)

    Iida, H.; Kanno, I.; Miura, S.; Murakami, M.; Takahashi, V.; Kemura, K.

    1986-01-01

    The positron trajectories have been three-dimensionally simulated using a Monte-Carlo method under various strength of the magnetic field. More than 5 tesla of the field confined the positrons effectively, resulting in increase of the probability of the annihilation within a limited small region, hence the higher spatial resolution in positron emission tomography

  18. Quantification of Greenhouse Gas Emission Rates from strong Point Sources by Space-borne IPDA Lidar Measurements: Results from a Sensitivity Analysis Study

    Science.gov (United States)

    Ehret, G.; Kiemle, C.; Rapp, M.

    2017-12-01

    The practical implementation of the Paris Agreement (COP21) vastly profit from an independent, reliable and global measurement system of greenhouse gas emissions, in particular of CO2, in order to complement and cross-check national efforts. Most fossil-fuel CO2 emitters emanate from large sources such as cities and power plants. These emissions increase the local CO2 abundance in the atmosphere by 1-10 parts per million (ppm) which is a signal that is significantly larger than the variability from natural sources and sinks over the local source domain. Despite these large signals, they are only sparsely sampled by the ground-based network which calls for satellite measurements. However, none of the existing and forthcoming passive satellite instruments, operating in the NIR spectral domain, can measure CO2 emissions at night time or in low sunlight conditions and in high latitude regions in winter times. The resulting sparse coverage of passive spectrometers is a serious limitation, particularly for the Northern Hemisphere, since these regions exhibit substantial emissions during the winter as well as other times of the year. In contrast, CO2 measurements by an Integrated Path Differential Absorption (IPDA) Lidar are largely immune to these limitations and initial results from airborne application look promising. In this study, we discuss the implication for a space-borne IPDA Lidar system. A Gaussian plume model will be used to simulate the CO2-distribution of large power plants downstream to the source. The space-borne measurements are simulated by applying a simple forward model based on Gaussian error distribution. Besides the sampling frequency, the sampling geometry (e.g. measurement distance to the emitting source) and the error of the measurement itself vastly impact on the flux inversion performance. We will discuss the results by incorporating Gaussian plume and mass budget approaches to quantify the emission rates.

  19. (F)UV Spectral Analysis of Hot, Hydrogen-Rich Central Stars of Planetary Nebulae

    Science.gov (United States)

    Ziegler, M.; Rauch, T.; Werner, K.; Kruk, J. W.

    2010-11-01

    Metal abundances of CSPNe are not well known although they provide important constraints on AGB nucleosynthesis. We aim to determine metal abundances of two hot, hydrogen-rich CSPNe (namely of A35 and NGC3587, the latter also known as M97 or the Owl Nebula) and to derive Teff and log g precisely from high-resolution, high-S/N (far-) ultraviolet observations obtained with FUSE and HST/STIS. For this purpose, we utilize NLTE model atmospheres calculated with TMAP, the Tübingen Model Atmosphere Package. Due to strong line absorption of the ISM, simultaneous modeling of interstellar features has become a standard tool in our analyses. We present preliminary results, demonstrating the importance of combining stellar and interstellar models, in order to clearly identify and measure the strengths of strategic photospheric lines.

  20. Livestock induces strong spatial heterogeneity of soil CO2, N2O and CH4 emissions within a semi-arid sylvo-pastoral landscape in West Africa

    Institute of Scientific and Technical Information of China (English)

    Mohamed H ASSOUMA; Dominique SER(C)A; Frédéric GU(E)RIN; Vincent BLANFORT; Philippe LECOMTE; Ibra TOUR(E); Alexandre ICKOWICZ

    2017-01-01

    Greenhouse gas (GHG) emissions from the surface soils and surface water receiving animal excreta may be important components of the GHG balance of terrestrial ecosystems,but the associated processes are poorly documented in tropical environments,especially in tropical arid and semi-arid areas.A typical sylvo-pastoral landscape in the semi-arid zone of Senegal,West Africa,was investigated in this study.The study area (706 km2 of managed pastoral land) was a circular zone with a radius of 15 km centered on a borehole used to water livestock.The landscape supports a stocking rate ranging from 0.11 to 0.39 tropical livestock units per hectare depending on the seasonal movements of the livestock.Six landscape units were investigated (land in the vicinity of the borehole,natural ponds,natural rangelands,forest plantations,settlements,and enclosed plots).Carbon dioxide (CO2),nitrous oxide (N2O) and methane (CH4) fluxes were measured with static chambers set up at 13 sites covering the six landscape units,and the 13 sites are assumed to be representative of the spatial heterogeneity of the emissions.A total of 216 fluxes were measured during the one-year study period (May 2014 to April 2015).At the landscape level,soits and surface water emitted an average 19.8 t C-CO2 eq/(hm2·a) (CO2:82%,N2O:15%,and CH4:3%),but detailed results revealed notable spatial heterogeneity of GHG emissions.CO2 fluxes ranged from 1148.2 (±91.6) mg/(m2·d) in rangelands to 97,980.2 (±14,861.7) mg/(m2·d) in surface water in the vicinity of the borehole.N2O fluxes ranged from 0.6 (±0.1) mg/(m2·d) in forest plantations to 22.6 (±10.8) mg/(m2·d) in the vicinity of the borehole.CH4 fluxes ranged from-3.2 (±0.3) mg/(m2·d) in forest plantations to 8788.5 (±2295.9) mg/(m2·d) from surface water in the vicinity of the borehole.This study identified GHG emission "hot spots" in the landscape.Emissions from the surface soilts were significantly higher in the landscape units most frequently

  1. <strong>Mini-project>

    DEFF Research Database (Denmark)

    Katajainen, Jyrki

    2008-01-01

    In this project the goal is to develop the safe * family of containers for the CPH STL. The containers to be developed should be safer and more reliable than any of the existing implementations. A special focus should be put on strong exception safety since none of the existing prototypes available...

  2. Measurement of Anomalously Strong Emission from the 1s-9p Transition in the Spectrum of H-like Phosphorus Following Charge Exchange with Molecular Hydrogen

    Science.gov (United States)

    Leutenegger, M. A.; Beiersdorfer, P.; Brown, G. V.; Kelley, R. L.; Porter, F. S.

    2010-01-01

    We have measured K-shell x-ray spectra of highly ionized argon and phosphorus following charge exchange with molecular hydrogen at low collision energy in an electron beam ion trap using an x-ray calorimeter array with approx.6 eV resolution. We find that the emission at the high-end of the Lyman series is greater by a factor of two for phosphorus than for argon, even though the measurement was performed concurrently and the atomic numbers are similar. This does not agree with current theoretical models and deviates from the trend observed in previous measurements.

  3. Strong interactions

    International Nuclear Information System (INIS)

    Froissart, Marcel

    1976-01-01

    Strong interactions are introduced by their more obvious aspect: nuclear forces. In hadron family, the nucleon octet, OMEGA - decuplet, and quark triply are successively considered. Pion wave having been put at the origin of nuclear forces, low energy phenomena are described, the force being explained as an exchange of structure corresponding to a Regge trajectory in a variable rotating state instead of the exchange of a well defined particle. At high energies the concepts of pomeron, parton and stratons are introduced, pionization and fragmentation are briefly differentiated [fr

  4. RE-EVALUATING WASP-12b: STRONG EMISSION AT 2.315 μm, DEEPER OCCULTATIONS, AND AN ISOTHERMAL ATMOSPHERE

    International Nuclear Information System (INIS)

    Crossfield, Ian J. M.; Barman, Travis; Hansen, Brad M. S.; Tanaka, Ichi; Kodama, Tadayuki

    2012-01-01

    We revisit the atmospheric properties of the extremely hot Jupiter WASP-12b in light of several new developments. First, we present new narrowband (2.315 μm) secondary eclipse photometry, which exhibits a planet/star flux ratio of 0.45% ± 0.06%, corresponding to a brightness temperature of 3640 ± 230 K; second, recent Spitzer/Infrared Array Camera and Hubble Space Telescope/Wide Field Camera 3 observations; and third, a recently observed star only 1'' from WASP-12, which has diluted previous observations and which we further characterize here. We correct past WASP-12b eclipse measurements for the presence of this object, and we revisit the interpretation of WASP-12b's dilution-corrected emission spectrum. The resulting planetary emission spectrum is well approximated by a blackbody, and consequently our primary conclusion is that the planet's infrared photosphere is nearly isothermal. Thus, secondary eclipse spectroscopy is relatively ill suited to constrain WASP-12b's atmospheric abundances, and transmission spectroscopy may be necessary to achieve this goal.

  5. Multidimensional Models of Type Ia Supernova Nebular Spectra: Strong Emission Lines from Stripped Companion Gas Rule Out Classic Single-degenerate Systems

    Science.gov (United States)

    Botyánszki, János; Kasen, Daniel; Plewa, Tomasz

    2018-01-01

    The classic single-degenerate model for the progenitors of Type Ia supernova (SN Ia) predicts that the supernova ejecta should be enriched with solar-like abundance material stripped from the companion star. Spectroscopic observations of normal SNe Ia at late times, however, have not resulted in definite detection of hydrogen. In this Letter, we study line formation in SNe Ia at nebular times using non-LTE spectral modeling. We present, for the first time, multidimensional radiative transfer calculations of SNe Ia with stripped material mixed in the ejecta core, based on hydrodynamical simulations of ejecta–companion interaction. We find that interaction models with main-sequence companions produce significant Hα emission at late times, ruling out these types of binaries being viable progenitors of SNe Ia. We also predict significant He I line emission at optical and near-infrared wavelengths for both hydrogen-rich or helium-rich material, providing an additional observational probe of stripped ejecta. We produce models with reduced stripped masses and find a more stringent mass limit of M st ≲ 1 × 10‑4 M ⊙ of stripped companion material for SN 2011fe.

  6. Strong violet-blue light photoluminescence emission at room temperature in SrZrO3: Joint experimental and theoretical study

    International Nuclear Information System (INIS)

    Longo, V.M.; Cavalcante, L.S.; Erlo, R.; Mastelaro, V.R.; Figueiredo, A.T. de; Sambrano, J.R.; Lazaro, S. de; Freitas, A.Z.; Gomes, L.; Vieira, N.D.; Varela, J.A.; Longo, Elson

    2008-01-01

    Ultrafine ordered and disordered SrZrO 3 powders were prepared by the polymeric precursor method. The structural evolution from structural disorder to order was monitored by X-ray diffraction and X-ray absorption near-edge spectroscopy. Complex cluster vacancies [ZrO 5 .V O Z ]and[SrO 11 .V O Z ] (where V O Z =V O X , V O · andV O ·· ) were proposed for disordered powders. The intense violet-blue light photoluminescence emission measured at room temperature in the disordered powders was attributed to complex cluster vacancies. High-level quantum mechanical calculations within the density functional theory framework were used to interpret the experimental results

  7. THE BOSS EMISSION-LINE LENS SURVEY. II. INVESTIGATING MASS-DENSITY PROFILE EVOLUTION IN THE SLACS+BELLS STRONG GRAVITATIONAL LENS SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, Adam S.; Brownstein, Joel R.; Shu Yiping; Arneson, Ryan A. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT 84112 (United States); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Schlegel, David J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Eisenstein, Daniel J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Wake, David A. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Connolly, Natalia [Department of Physics, Hamilton College, Clinton, NY 13323 (United States); Maraston, Claudia [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Weaver, Benjamin A., E-mail: bolton@astro.utah.edu [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)

    2012-09-20

    We present an analysis of the evolution of the central mass-density profile of massive elliptical galaxies from the SLACS and BELLS strong gravitational lens samples over the redshift interval z Almost-Equal-To 0.1-0.6, based on the combination of strong-lensing aperture mass and stellar velocity-dispersion constraints. We find a significant trend toward steeper mass profiles (parameterized by the power-law density model with {rho}{proportional_to}r {sup -{gamma}}) at later cosmic times, with magnitude d < {gamma} > /dz = -0.60 {+-} 0.15. We show that the combined lens-galaxy sample is consistent with a non-evolving distribution of stellar velocity dispersions. Considering possible additional dependence of <{gamma} > on lens-galaxy stellar mass, effective radius, and Sersic index, we find marginal evidence for shallower mass profiles at higher masses and larger sizes, but with a significance that is subdominant to the redshift dependence. Using the results of published Monte Carlo simulations of spectroscopic lens surveys, we verify that our mass-profile evolution result cannot be explained by lensing selection biases as a function of redshift. Interpreted as a true evolutionary signal, our result suggests that major dry mergers involving off-axis trajectories play a significant role in the evolution of the average mass-density structure of massive early-type galaxies over the past 6 Gyr. We also consider an alternative non-evolutionary hypothesis based on variations in the strong-lensing measurement aperture with redshift, which would imply the detection of an 'inflection zone' marking the transition between the baryon-dominated and dark-matter halo-dominated regions of the lens galaxies. Further observations of the combined SLACS+BELLS sample can constrain this picture more precisely, and enable a more detailed investigation of the multivariate dependences of galaxy mass structure across cosmic time.

  8. The GALEX Ultraviolet Virgo Cluster Survey (GUViCS). VII. Brightest cluster galaxy UV upturn and the FUV-NUV color up to redshift 0.35

    Science.gov (United States)

    Boissier, S.; Cucciati, O.; Boselli, A.; Mei, S.; Ferrarese, L.

    2018-03-01

    Context. At low redshift, early-type galaxies often exhibit a rising flux with decreasing wavelength in the 1000-2500 Å range, called "UV upturn". The origin of this phenomenon is debated, and its evolution with redshift is poorly constrained. The observed GALEX FUV-NUV color can be used to probe the UV upturn approximately to redshift 0.5. Aim. We provide constraints on the existence of the UV upturn up to redshift 0.4 in the brightest cluster galaxies (BCG) located behind the Virgo cluster, using data from the GUViCS survey. Methods: We estimate the GALEX far-UV (FUV) and near-UV (NUV) observed magnitudes for BCGs from the maxBCG catalog in the GUViCS fields. We increase the number of nonlocal galaxies identified as BCGs with GALEX photometry from a few tens of galaxies to 166 (64 when restricting this sample to relatively small error bars). We also estimate a central color within a 20 arcsec aperture. By using the r-band luminosity from the maxBCG catalog, we can separate blue FUV-NUV due to recent star formation and candidate upturn cases. We use Lick indices to verify their similarity to redshift 0 upturn cases. Results: We clearly detect a population of blue FUV-NUV BCGs in the redshift range 0.10-0.35, vastly improving the existing constraints at these epochs by increasing the number of galaxies studied, and by exploring a redshift range with no previous data (beyond 0.2), spanning one more Gyr in the past. These galaxies bring new constraints that can help distinguish between assumptions concerning the stellar populations causing the UV upturn phenomenon. The existence of a large number of UV upturns around redshift 0.25 favors the existence of a binary channel among the sources proposed in the literature. Tables 2-5 are 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/611/A42

  9. A Zero-Dimensional Organic Seesaw-Shaped Tin Bromide with Highly Efficient Strongly Stokes-Shifted Deep-Red Emission

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Chenkun [College of Engineering, Tallahassee, FL (United States). Dept. of Chemical and Biomedical Engineering; Lin, Haoran [College of Engineering, Tallahassee, FL (United States). Dept. of Chemical and Biomedical Engineering; Shi, Hongliang [Beihang Univ., Beijing (China). Dept. of Physics; Tian, Yu [Materials Science and Engineering Program, Florida State University, Tallahassee FL 32306 USA; Pak, Chongin [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry; Shatruk, Michael [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry; Zhou, Yan [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry; Djurovich, Peter [Univ. of Southern California, Los Angeles, CA (United States). Dept. of Chemistry; Du, Mao-Hua [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division, Center for Radiation Detection Materials and Systems; Ma, Biwu [College of Engineering, Tallahassee, FL (United States). Dept. of Chemical and Biomedical Engineering; Beihang Univ., Beijing (China). Dept. of Physics; Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry

    2017-12-21

    The synthesis and characterization is reported of (C9NH20)2SnBr4, a novel organic metal halide hybrid with a zero-dimensional (0D) structure, in which individual seesaw-shaped tin (II) bromide anions (SnBr42-) are co-crystallized with 1-butyl-1-methylpyrrolidinium cations (C9NH20+). Upon photoexcitation, the bulk crystals exhibit a highly efficient broadband deep-red emission peaked at 695 nm, with a large Stokes shift of 332 nm and a high quantum efficiency of around 46 %. Furthermore, the unique photophysical properties of this hybrid material are attributed to two major factors: 1) the 0D structure allowing the bulk crystals to exhibit the intrinsic properties of individual SnBr42- species, and 2) the seesaw structure then enables a pronounced excited state structural deformation as confirmed by density functional theory (DFT) calculations.

  10. What is the physical origin of strong Lyα emission? II. Gas kinematics and distribution of Lyα emitters

    Energy Technology Data Exchange (ETDEWEB)

    Shibuya, Takatoshi; Ouchi, Masami; Ono, Yoshiaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Nakajima, Kimihiko; Hashimoto, Takuya; Shimasaku, Kazuhiro; Goto, Ryosuke [Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Rauch, Michael [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Gauthier, Jean-Rene [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Mori, Masao; Umemura, Masayuki, E-mail: shibyatk@icrr.u-tokyo.ac.jp [Center for Computational Sciences, The University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan)

    2014-06-10

    We present a statistical study of velocities of Lyα, interstellar (IS) absorption, and nebular lines and gas covering fraction for Lyα emitters (LAEs) at z ≅ 2. We make a sample of 22 LAEs with a large Lyα equivalent width (EW) of ≳ 50 Å based on our deep Keck/Low Resolution Imaging Spectrometer (LRIS) observations, in conjunction with spectroscopic data from the Subaru/Fiber Multi Object Spectrograph program and the literature. We estimate the average velocity offset of Lyα from a systemic redshift determined with nebular lines to be Δv {sub Lyα} = 234 ± 9 km s{sup –1}. Using a Kolmogorov-Smirnov test, we confirm the previous claim of Hashimoto et al. that the average Δv {sub Lyα} of LAEs is smaller than that of Lyman break galaxies (LBGs). Our LRIS data successfully identify blueshifted multiple IS absorption lines in the UV continua of four LAEs on an individual basis. The average velocity offset of IS absorption lines from a systemic redshift is Δv {sub IS} = 204 ± 27 km s{sup –1}, indicating LAEs' gas outflow with a velocity comparable to typical LBGs. Thus, the ratio R{sub IS}{sup Lyα}≡Δv{sub Lyα}/Δv{sub IS} of LAEs is around unity, suggestive of low impacts on Lyα transmission by resonant scattering of neutral hydrogen in the IS medium. We find an anti-correlation between Lyα EW and the covering fraction, f{sub c} , estimated from the depth of absorption lines, where f{sub c} is an indicator of average neutral hydrogen column density, N {sub H} {sub I}. The results of our study support the idea that N {sub H} {sub I} is a key quantity determining Lyα emissivity.

  11. The 1600 Å Emission Bump in Protoplanetary Disks: A Spectral Signature of H{sub 2}O Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    France, Kevin [Laboratory for Atmospheric and Space Physics, University of Colorado, 600 UCB, Boulder, CO 80309 (United States); Roueff, Evelyne; Abgrall, Hervé, E-mail: kevin.france@colorado.edu [LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-92190, Meudon (France)

    2017-08-01

    The FUV continuum spectrum of many accreting pre-main sequence stars, Classical T Tauri Stars (CTTSs), does not continue smoothly from the well-studied Balmer continuum emission in the NUV, suggesting that additional processes contribute to the short-wavelength emission in these objects. The most notable spectral feature in the FUV continuum of some CTTSs is a broad emission approximately centered at 1600 Å, which has been referred to as the “1600 Å Bump.” The origin of this feature remains unclear. In an effort to better understand the molecular properties of planet-forming disks and the UV spectral properties of accreting protostars, we have assembled archival FUV spectra of 37 disk-hosting systems observed by the Hubble Space Telescope -Cosmic Origins Spectrograph. Clear 1600 Å Bump emission is observed above the smooth, underlying 1100–1800 Å continuum spectrum in 19/37 Classical T Tauri disks in the HST -COS sample, with the detection rate in transition disks (8/8) being much higher than that in primordial or non-transition sources (11/29). We describe a spectral deconvolution analysis to separate the Bump (spanning 1490–1690 Å) from the underlying FUV continuum, finding an average Bump luminosity L (Bump) ≈ 7 × 10{sup 29} erg s{sup −1}. Parameterizing the Bump with a combination of Gaussian and polynomial components, we find that the 1600 Å Bump is characterized by a peak wavelength λ {sub o} = 1598.6 ± 3.3 Å, with FWHM = 35.8 ± 19.1 Å. Contrary to previous studies, we find that this feature is inconsistent with models of H{sub 2} excited by electron -impact. We show that this Bump makes up between 5%–50% of the total FUV continuum emission in the 1490–1690 Å band and emits roughly 10%–80% of the total fluorescent H{sub 2} luminosity for stars with well-defined Bump features. Energetically, this suggests that the carrier of the 1600 Å Bump emission is powered by Ly α photons. We argue that the most likely mechanism

  12. FUV Spectral Signatures of Molecules and the Evolution of the Gaseous Coma of Comet 67P/Churyumov–Gerasimenko

    Science.gov (United States)

    Feldman, Paul D.; A’Hearn, Michael F.; Bertaux, Jean-Loup; Feaga, Lori M.; Keeney, Brian A.; Knight, Matthew M.; Noonan, John; Parker, Joel Wm.; Schindhelm, Eric; Steffl, Andrew J.; Stern, S. Alan; Vervack, Ronald J.; Weaver, Harold A.

    2018-01-01

    The Alice far-ultraviolet imaging spectrograph onboard Rosetta observed emissions from atomic and molecular species from within the coma of comet 67P/Churyumov–Gerasimenko during the entire escort phase of the mission from 2014 August to 2016 September. The initial observations showed that emissions of atomic hydrogen and oxygen close to the surface were produced by energetic electron impact dissociation of H2O. Following delivery of the lander, Philae, on 2014 November 12, the trajectory of Rosetta shifted to near-terminator orbits that allowed for these emissions to be observed against the shadowed nucleus that, together with the compositional heterogeneity, enabled us to identify unique spectral signatures of dissociative electron impact excitation of H2O, CO2, and O2. CO emissions were found to be due to both electron and photoexcitation processes. Thus, we are able, from far-ultraviolet spectroscopy, to qualitatively study the evolution of the primary molecular constituents of the gaseous coma from start to finish of the escort phase. Our results show asymmetric outgassing of H2O and CO2 about perihelion, H2O dominant before and CO2 dominant after, consistent with the results from both the in situ and other remote sensing instruments on Rosetta.

  13. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  14. Strong Mechanoluminescence from Oxynitridosilicate Phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lin; Xu Chaonan; Yamada, Hiroshi, E-mail: cn-xu@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 807-1 Shuku, Tosu, Saga 841-0052 (Japan)

    2011-10-29

    We successfully developed a novel Mechanoluminescence (ML) material with water resistance, oxynitridosilicate; BaSi{sub 2}O{sub 2}N{sub 2}: Eu{sup 2+}. The crystal structure, photoluminescence (PL) and ML properties were characterized. The ML of BaSi{sub 2}O{sub 2}N{sub 2}: Eu{sup 2+} is so strong that the blue-green emission can be observed by the naked eyes clearly. In addition, it shows superior water resistance property. No changes were found in the ML intensities during the total water treatment test.

  15. The 1600 Å Emission Bump in Protoplanetary Disks: A Spectral Signature of H2O Dissociation

    Science.gov (United States)

    France, Kevin; Roueff, Evelyne; Abgrall, Hervé

    2017-08-01

    The FUV continuum spectrum of many accreting pre-main sequence stars, Classical T Tauri Stars (CTTSs), does not continue smoothly from the well-studied Balmer continuum emission in the NUV, suggesting that additional processes contribute to the short-wavelength emission in these objects. The most notable spectral feature in the FUV continuum of some CTTSs is a broad emission approximately centered at 1600 Å, which has been referred to as the “1600 Å Bump.” The origin of this feature remains unclear. In an effort to better understand the molecular properties of planet-forming disks and the UV spectral properties of accreting protostars, we have assembled archival FUV spectra of 37 disk-hosting systems observed by the Hubble Space Telescope-Cosmic Origins Spectrograph. Clear 1600 Å Bump emission is observed above the smooth, underlying 1100-1800 Å continuum spectrum in 19/37 Classical T Tauri disks in the HST-COS sample, with the detection rate in transition disks (8/8) being much higher than that in primordial or non-transition sources (11/29). We describe a spectral deconvolution analysis to separate the Bump (spanning 1490-1690 Å) from the underlying FUV continuum, finding an average Bump luminosity L(Bump) ≈ 7 × 1029 erg s-1. Parameterizing the Bump with a combination of Gaussian and polynomial components, we find that the 1600 Å Bump is characterized by a peak wavelength λ o = 1598.6 ± 3.3 Å, with FWHM = 35.8 ± 19.1 Å. Contrary to previous studies, we find that this feature is inconsistent with models of H2 excited by electron -impact. We show that this Bump makes up between 5%-50% of the total FUV continuum emission in the 1490-1690 Å band and emits roughly 10%-80% of the total fluorescent H2 luminosity for stars with well-defined Bump features. Energetically, this suggests that the carrier of the 1600 Å Bump emission is powered by Lyα photons. We argue that the most likely mechanism is Lyα-driven dissociation of H2O in the inner disk, r

  16. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally...

  17. Strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Goldman, M.V.

    1984-01-01

    After a brief discussion of beam-excited Langmuir turbulence in the solar wind, we explain the criteria for wave-particle, three-wave and strong turbulence interactions. We then present the results of a numerical integration of the Zakharov equations, which describe the strong turbulence saturation of a weak (low-density) high energy, bump-on-tail beam instability. (author)

  18. Spatial distribution of FIR rotationally excited CH+ and OH emission lines in the Orion Bar PDR⋆

    Science.gov (United States)

    Parikka, A.; Habart, E.; Bernard-Salas, J.; Goicoechea, J. R.; Abergel, A.; Pilleri, P.; Dartois, E.; Joblin, C.; Gerin, M.; Godard, B.

    2016-01-01

    Context The methylidyne cation (CH+) and hydroxyl (OH) are key molecules in the warm interstellar chemistry, but their formation and excitation mechanisms are not well understood. Their abundance and excitation are predicted to be enhanced by the presence of vibrationally excited H2 or hot gas (~500–1000 K) in photodissociation regions with high incident FUV radiation field. The excitation may also originate in dense gas (> 105 cm−3) followed by nonreactive collisions with H2, H, and electrons. Previous observations of the Orion Bar suggest that the rotationally excited CH+ and OH correlate with the excited CO, a tracer of dense and warm gas, and formation pumping contributes to CH+ excitation. Aims Our goal is to examine the spatial distribution of the rotationally excited CH+ and OH emission lines in the Orion Bar in order to establish their physical origin and main formation and excitation mechanisms. Methods We present spatially sampled maps of the CH+ J=3-2 transition at 119.8 µm and the OH Λ-doublet at 84 µm in the Orion Bar over an area of 110″×110″ with Herschel (PACS). We compare the spatial distribution of these molecules with those of their chemical precursors, C+, O and H2, and tracers of warm and dense gas (high-J CO). We assess the spatial variation of CH+ J=2-1 velocity-resolved line profile at 1669 GHz with Herschel HIFI spectrometer observations. Results The OH and especially CH+ lines correlate well with the high-J CO emission and delineate the warm and dense molecular region at the edge of the Bar. While notably similar, the differences in the CH+ and OH morphologies indicate that CH+ formation and excitation are strongly related to the observed vibrationally excited H2. This, together with the observed broad CH+ line widths, indicates that formation pumping contributes to the excitation of this reactive molecular ion. Interestingly, the peak of the rotationally excited OH 84 µm emission coincides with a bright young object, proplyd

  19. Spatial distribution of FIR rotationally excited CH+ and OH emission lines in the Orion Bar PDR.

    Science.gov (United States)

    Parikka, A; Habart, E; Bernard-Salas, J; Goicoechea, J R; Abergel, A; Pilleri, P; Dartois, E; Joblin, C; Gerin, M; Godard, B

    2017-03-01

    The methylidyne cation (CH + ) and hydroxyl (OH) are key molecules in the warm interstellar chemistry, but their formation and excitation mechanisms are not well understood. Their abundance and excitation are predicted to be enhanced by the presence of vibrationally excited H 2 or hot gas (~500-1000 K) in photodissociation regions with high incident FUV radiation field. The excitation may also originate in dense gas (> 10 5 cm -3 ) followed by nonreactive collisions with H 2 , H, and electrons. Previous observations of the Orion Bar suggest that the rotationally excited CH + and OH correlate with the excited CO, a tracer of dense and warm gas, and formation pumping contributes to CH + excitation. Our goal is to examine the spatial distribution of the rotationally excited CH + and OH emission lines in the Orion Bar in order to establish their physical origin and main formation and excitation mechanisms. We present spatially sampled maps of the CH + J=3-2 transition at 119.8 µm and the OH Λ-doublet at 84 µm in the Orion Bar over an area of 110″×110″ with Herschel (PACS). We compare the spatial distribution of these molecules with those of their chemical precursors, C + , O and H 2 , and tracers of warm and dense gas (high-J CO). We assess the spatial variation of CH + J=2-1 velocity-resolved line profile at 1669 GHz with Herschel HIFI spectrometer observations. The OH and especially CH + lines correlate well with the high-J CO emission and delineate the warm and dense molecular region at the edge of the Bar. While notably similar, the differences in the CH + and OH morphologies indicate that CH + formation and excitation are strongly related to the observed vibrationally excited H 2 . This, together with the observed broad CH + line widths, indicates that formation pumping contributes to the excitation of this reactive molecular ion. Interestingly, the peak of the rotationally excited OH 84 µm emission coincides with a bright young object, proplyd 244

  20. Strong intrinsic motivation

    OpenAIRE

    Dessi, Roberta; Rustichini, Aldo

    2015-01-01

    A large literature in psychology, and more recently in economics, has argued that monetary rewards can reduce intrinsic motivation. We investigate whether the negative impact persists when intrinsic motivation is strong, and test this hypothesis experimentally focusing on the motivation to undertake interesting and challenging tasks, informative about individual ability. We find that this type of task can generate strong intrinsic motivation, that is impervious to the effect of monetary incen...

  1. Bitcoin Meets Strong Consistency

    OpenAIRE

    Decker, Christian; Seidel, Jochen; Wattenhofer, Roger

    2014-01-01

    The Bitcoin system only provides eventual consistency. For everyday life, the time to confirm a Bitcoin transaction is prohibitively slow. In this paper we propose a new system, built on the Bitcoin blockchain, which enables strong consistency. Our system, PeerCensus, acts as a certification authority, manages peer identities in a peer-to-peer network, and ultimately enhances Bitcoin and similar systems with strong consistency. Our extensive analysis shows that PeerCensus is in a secure state...

  2. Strong gravity and supersymmetry

    International Nuclear Information System (INIS)

    Chamseddine, Ali H.; Salam, A.; Strathdee, J.

    1977-11-01

    A supersymmetric theory is constructed for a strong f plus a weak g graviton, together with their accompanying massive gravitinos, by gaugin the gradel 0Sp(2,2,1)x 0Sp(2,2,1) structure. The mixing term between f and g fields, which makes the strong graviton massive, can be introduced through a spontaneous symmetry-breaking mechanism implemented in this note by constructing a non-linear realization of the symmetry group

  3. SPITZER IRAC COLOR DIAGNOSTICS FOR EXTENDED EMISSION IN STAR-FORMING REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    Ybarra, Jason E.; Tapia, Mauricio; Román-Zúñiga, Carlos G. [Instituto de Astronomía, Universidad Nacional Autónoma de Mexíco, Unidad Académica en Ensenada, Km 103 Carr. Tijuana-Ensenada, 22860 Ensenada BC (Mexico); Lada, Elizabeth A., E-mail: jybarra@astro.unam.mx [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States)

    2014-10-20

    The infrared data from the Spitzer Space Telescope are an invaluable tool for identifying physical processes in star formation. In this study, we calculate the Infrared Array Camera (IRAC) color space of UV fluorescent H{sub 2} and polycyclic aromatic hydrocarbon (PAH) emission in photodissociation regions (PDRs) using the Cloudy code with PAH opacities from Draine and Li. We create a set of color diagnostics that can be applied to study the structure of PDRs and to distinguish between FUV-excited and shock-excited H{sub 2} emission. To test this method, we apply these diagnostics to Spitzer IRAC data of NGC 2316. Our analysis of the structure of the PDR is consistent with previous studies of the region. In addition to UV excited emission, we identify shocked gas that may be part of an outflow originating from the cluster.

  4. SPITZER IRAC COLOR DIAGNOSTICS FOR EXTENDED EMISSION IN STAR-FORMING REGIONS

    International Nuclear Information System (INIS)

    Ybarra, Jason E.; Tapia, Mauricio; Román-Zúñiga, Carlos G.; Lada, Elizabeth A.

    2014-01-01

    The infrared data from the Spitzer Space Telescope are an invaluable tool for identifying physical processes in star formation. In this study, we calculate the Infrared Array Camera (IRAC) color space of UV fluorescent H 2 and polycyclic aromatic hydrocarbon (PAH) emission in photodissociation regions (PDRs) using the Cloudy code with PAH opacities from Draine and Li. We create a set of color diagnostics that can be applied to study the structure of PDRs and to distinguish between FUV-excited and shock-excited H 2 emission. To test this method, we apply these diagnostics to Spitzer IRAC data of NGC 2316. Our analysis of the structure of the PDR is consistent with previous studies of the region. In addition to UV excited emission, we identify shocked gas that may be part of an outflow originating from the cluster

  5. Electromagnetic processes in strong crystalline fields

    CERN Multimedia

    2007-01-01

    We propose a number of new investigations on aspects of radiation from high energy electron and positron beams (10-300 GeV) in single crystals and amorphous targets. The common heading is radiation emission by electrons and positrons in strong electromagnetic fields, but as the setup is quite versatile, other related phenomena in radiation emission can be studied as well. The intent is to clarify the role of a number of important aspects of radiation in strong fields as e.g. observed in crystals. We propose to measure trident 'Klein-like' production in strong crystalline fields, 'crystalline undulator' radiation, 'sandwich' target phenomena, LPM suppression of pair production as well as axial and planar effects in contributions of spin to the radiation.

  6. Strongly interacting Fermi gases

    Directory of Open Access Journals (Sweden)

    Bakr W.

    2013-08-01

    Full Text Available Strongly interacting gases of ultracold fermions have become an amazingly rich test-bed for many-body theories of fermionic matter. Here we present our recent experiments on these systems. Firstly, we discuss high-precision measurements on the thermodynamics of a strongly interacting Fermi gas across the superfluid transition. The onset of superfluidity is directly observed in the compressibility, the chemical potential, the entropy, and the heat capacity. Our measurements provide benchmarks for current many-body theories on strongly interacting fermions. Secondly, we have studied the evolution of fermion pairing from three to two dimensions in these gases, relating to the physics of layered superconductors. In the presence of p-wave interactions, Fermi gases are predicted to display toplogical superfluidity carrying Majorana edge states. Two possible avenues in this direction are discussed, our creation and direct observation of spin-orbit coupling in Fermi gases and the creation of fermionic molecules of 23Na 40K that will feature strong dipolar interactions in their absolute ground state.

  7. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  8. Strong enhancement of the upconversion emission in ZrO{sub 2}: Yb{sup 3+}, Er{sup 3+}, Gd{sup 3+} nanocubes synthesized with Na{sub 2}S

    Energy Technology Data Exchange (ETDEWEB)

    Urbina-Frías, Alejandra; López-Luke, Tzarara; Oliva, Jorge [Centro de Investigaciones en Óptica, A.P. 1-948, León, Guanajuato 37150 (Mexico); Salas, Pedro [Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, A.P. 1-1010, Querétaro 76000 (Mexico); Torres-Castro, Alejandro [Universidad Autónoma de Nuevo León, A.P. 126-F, Monterrey, NeNuevo Leon 66450 (Mexico); De la Rosa, Elder, E-mail: elder@cio.mx [Centro de Investigaciones en Óptica, A.P. 1-948, León, Guanajuato 37150 (Mexico)

    2016-04-15

    In this work, the structural, morphological and luminescent characterization of ZrO{sub 2}:Yb{sup 3+},Er{sup 3+}, Gd{sup 3+} nanocrystals prepared with Na{sub 2}S by precipitation method is reported. The XRD spectra showed a mixture of tetragonal (88%) and monoclinic phases (12%) in samples fabricated with and without Na{sub 2}S. The tetragonal phase (100%) was stabilized by the introduction of the Gd{sup 3+}. According to TEM images, samples showed a cubic morphology with an average size of 150 nm, when both, Na{sub 2}S and Gd{sup 3+} were added. Red (678 nm), green (545 nm) and ultraviolet (275, 285 nm) emissions were obtained as a result of the upconversion process due to the energy transfer between Yb{sup 3+}–Er{sup 3+}–Gd{sup 3+} ions, under 970 nm of excitation. The integrated red band showed an increment of 40% and 125%, for samples prepared with Na{sub 2}S and combined with Gd{sup 3+}, respectively, compared to the ZrO{sub 2}:Yb{sup 3+}–Er{sup 3+} sample. Such increments are explained in terms of the surface pasivation by using Na{sub 2}S during the synthesis process and the role of Gd{sup 3+} as a reservoir of energy from Er{sup 3+}. - Highlights: • ZrO{sub 2}:Yb,Er nanoparticles were synthesized by a precipitation method. • ZrO{sub 2}:Yb,Er nanoparticles were prepared with Na{sub 2}S and sensitized with Gd{sup 3+}. • An increment of 40% in luminescence occurred in samples prepared with Na{sub 2}S. • An increment of 125% were obtained by the synergistic effect between Na{sub 2}S and Gd3{sup +}.

  9. Ion cyclotron emission by spontaneous emission

    Energy Technology Data Exchange (ETDEWEB)

    Da Costa, O [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Gresillon, D [Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises

    1994-07-01

    The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs.

  10. Ion cyclotron emission by spontaneous emission

    International Nuclear Information System (INIS)

    Da Costa, O.; Gresillon, D.

    1994-01-01

    The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs

  11. Atoms in strong laser fields

    International Nuclear Information System (INIS)

    L'Huillier, A.

    2002-01-01

    When a high-power laser focuses into a gas of atoms, the electromagnetic field becomes of the same magnitude as the Coulomb field which binds a 1s electron in a hydrogen atom. 3 highly non-linear phenomena can happen: 1) ATI (above threshold ionization): electrons initially in the ground state absorb a large number of photons, many more than the minimum number required for ionization; 2) multiple ionization: many electrons can be emitted one at a time, in a sequential process, or simultaneously in a mechanism called direct or non-sequential; and 3) high order harmonic generation (HHG): efficient photon emission in the extreme ultraviolet range, in the form of high-order harmonics of the fundamental laser field can occur. The theoretical problem consists in solving the time dependent Schroedinger equation (TDSE) that describes the interaction of a many-electron atom with a laser field. A number of methods have been proposed to solve this problem in the case of a hydrogen atom or a single-active electron atom in a strong laser field. A large effort is presently being devoted to go beyond the single-active approximation. The understanding of the physics of the interaction between atoms and strong laser fields has been provided by a very simple model called ''simple man's theory''. A unified view of HHG, ATI, and non-sequential ionization, originating from the simple man's model and the strong field approximation, expressed in terms of electrons trajectories or quantum paths is slowly emerging. (A.C.)

  12. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  13. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  14. Strongly intensive quantities

    International Nuclear Information System (INIS)

    Gorenstein, M. I.; Gazdzicki, M.

    2011-01-01

    Analysis of fluctuations of hadron production properties in collisions of relativistic particles profits from use of measurable intensive quantities which are independent of system size variations. The first family of such quantities was proposed in 1992; another is introduced in this paper. Furthermore we present a proof of independence of volume fluctuations for quantities from both families within the framework of the grand canonical ensemble. These quantities are referred to as strongly intensive ones. Influence of conservation laws and resonance decays is also discussed.

  15. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  16. Strongly disordered superconductors

    International Nuclear Information System (INIS)

    Muttalib, K.A.

    1982-01-01

    We examine some universal effects of strong non-magnetic disorder on the electron-phonon and electron-electron interactions in a superconductor. In particular we explicitly take into account the effect of slow diffusion of electrons in a disordered medium by working in an exact impurity eigenstate representation. We find that the normal diffusion of electrons characterized by a constant diffusion coefficient does not lead to any significant correction to the electron-phonon or the effective electron-electron interactions in a superconductor. We then consider sufficiently strong disorder where Anderson localization of electrons becomes important and determine the effect of localization on the electron-electron interactions. We find that due to localization, the diffusion of electrons becomes anomalous in the sense that the diffusion coefficient becomes scale dependent. This results in an increase in the effective electron-electron interaction with increasing disorder. We propose that this provides a natural explanation for the unusual sensitivity of the transition temperature T/sub c/ of the high T/sub c/ superconductors (T/sub c/ > 10 0 K) to damage effects

  17. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  18. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  19. Strongly interacting Higgs bosons

    International Nuclear Information System (INIS)

    Appelquist, T.; Bernard, C.

    1980-01-01

    The sensitivity of present-energy weak interactions to a strongly interacting heavy-Higgs-boson sector is discussed. The gauged nonlinear sigma model, which is the limit of the linear model as the Higgs-boson mass goes to infinity, is used to organize and catalogue all possible heavy-Higgs-boson effects. As long as the SU(2)/sub L/ x SU(2)/sub R/ symmetry of the Higgs sector is preserved, these effects are found to be small, of the order of the square of the gauge coupling times logarithms (but not powers) of the Higgs-boson mass divided by the W mass. We work in the context of a simplified model with gauge group SU(2)/sub L/; the extension to SU(2)/sub L/ x U(1) is briefly discussed

  20. Cooling Curve of Strange Star in Strong Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Qin; LUO Zhi-Quan

    2008-01-01

    In this paper, firstly, we investigate the neutrino emissivity from quark Urca process in strong magnetic field. Then, we discuss the heat capacity of strange stars in strong magnetic field. Finally, we give the cooling curve in strong magnetic field. In order to make a comparison, we also give the corresponding cooling curve in the case of null magnetic field. It turns out that strange stars cool faster in strong magnetic field than that without magnetic field.

  1. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  2. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  3. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  4. BP's emissions trading system

    International Nuclear Information System (INIS)

    Victor, David G.; House, Joshua C.

    2006-01-01

    Between 1998 and 2001, BP reduced its emissions of greenhouse gases by more than 10%. BP's success in cutting emissions is often equated with its use of an apparently market-based emissions trading program. However no independent study has ever examined the rules and operation of BP's system and the incentives acting on managers to reduce emissions. We use interviews with key managers and with traders in several critical business units to explore the bound of BP's success with emissions trading. No money actually changed hands when permits were traded, and the main effect of the program was to create awareness of money-saving emission controls rather than strong price incentives. We show that the trading system did not operate like a 'textbook' cap and trade scheme. Rather, the BP system operated much like a 'safety valve' trading system, where managers let the market function until the cost of doing so surpassed what the company was willing to tolerate

  5. Strong Coupling between Plasmons and Organic Semiconductors

    Directory of Open Access Journals (Sweden)

    Joel Bellessa

    2014-05-01

    Full Text Available In this paper we describe the properties of organic material in strong coupling with plasmon, mainly based on our work in this field of research. The strong coupling modifies the optical transitions of the structure, and occurs when the interaction between molecules and plasmon prevails on the damping of the system. We describe the dispersion relation of different plasmonic systems, delocalized and localized plasmon, coupled to aggregated dyes and the typical properties of these systems in strong coupling. The modification of the dye emission is also studied. In the second part, the effect of the microscopic structure of the organics, which can be seen as a disordered film, is described. As the different molecules couple to the same plasmon mode, an extended coherent state on several microns is observed.

  6. Acoustic emission

    International Nuclear Information System (INIS)

    Nichols, R.W.

    1976-01-01

    The volume contains six papers which together provide an overall review of the inspection technique known as acoustic emission or stress wave emission. The titles are: a welder's introduction to acoustic emission technology; use of acoustic emission for detection of defects as they arise during fabrication; examples of laboratory application and assessment of acoustic emission in the United Kingdom; (Part I: acoustic emission behaviour of low alloy steels; Part II: fatigue crack assessment from proof testing and continuous monitoring); inspection of selected areas of engineering structures by acoustic emission; Japanese experience in laboratory and practical applications of acoustic emission to welded structures; and ASME acoustic emission code status. (U.K.)

  7. Strong white photoluminescence from annealed zeolites

    International Nuclear Information System (INIS)

    Bai, Zhenhua; Fujii, Minoru; Imakita, Kenji; Hayashi, Shinji

    2014-01-01

    The optical properties of zeolites annealed at various temperatures are investigated for the first time. The annealed zeolites exhibit strong white photoluminescence (PL) under ultraviolet light excitation. With increasing annealing temperature, the emission intensity of annealed zeolites first increases and then decreases. At the same time, the PL peak red-shifts from 495 nm to 530 nm, and then returns to 500 nm. The strongest emission appears when the annealing temperature is 500 °C. The quantum yield of the sample is measured to be ∼10%. The PL lifetime monotonously increases from 223 μs to 251 μs with increasing annealing temperature. The origin of white PL is ascribed to oxygen vacancies formed during the annealing process. -- Highlights: • The optical properties of zeolites annealed at various temperatures are investigated. • The annealed zeolites exhibit strong white photoluminescence. • The maximum PL enhancement reaches as large as 62 times. • The lifetime shows little dependence on annealing temperature. • The origin of white emission is ascribed to the oxygen vacancies

  8. Grassy Silica Nanoribbons and Strong Blue Luminescence

    Science.gov (United States)

    Wang, Shengping; Xie, Shuang; Huang, Guowei; Guo, Hongxuan; Cho, Yujin; Chen, Jun; Fujita, Daisuke; Xu, Mingsheng

    2016-09-01

    Silicon dioxide (SiO2) is one of the key materials in many modern technological applications such as in metal oxide semiconductor transistors, photovoltaic solar cells, pollution removal, and biomedicine. We report the accidental discovery of free-standing grassy silica nanoribbons directly grown on SiO2/Si platform which is commonly used for field-effect transistors fabrication without other precursor. We investigate the formation mechanism of this novel silica nanostructure that has not been previously documented. The silica nanoribbons are flexible and can be manipulated by electron-beam. The silica nanoribbons exhibit strong blue emission at about 467 nm, together with UV and red emissions as investigated by cathodoluminescence technique. The origins of the luminescence are attributed to various defects in the silica nanoribbons; and the intensity change of the blue emission and green emission at about 550 nm is discussed in the frame of the defect density. Our study may lead to rational design of the new silica-based materials for a wide range of applications.

  9. High-Resolution Electron-Impact Study of the Far-Ultraviolet Emission Spectrum of Molecular Hydrogen

    Science.gov (United States)

    Liu, Xian-Ming; Ahmed, Syed M.; Multari, Rosalie A.; James, Geoffrey K.; Ajello, Joseph M.

    1995-01-01

    The emission spectrum of molecular hydrogen produced by electron-impact excitation at 100 eV has been measured in the wavelength range 1140-1690 A. High-resolution, optically thin spectra (delta(lambda) = 0.136 A) of the far-ultraviolet (FUV) Lyman and Werner band systems have been obtained with a newly constructed 3 m spectrometer. Synthetic spectral intensities based on the transition probabilities calculated by Abgrall et al. are in very good agreement with experimentally observed intensities. Previous modeling that utilized Allison & Daigarno band transition probabilities with Hoenl-London factors breaks down when the transition moment has significant J dependence or when ro-vibrational coupling is significant. Ro-vibrational perturbation between upsilon = 14 of the B(sup 1)Sigma(sup +, sub u) state and upsilon = 3 of the C(sup 1)Pi(sub u) state and the rotational dependence of the transition moment in the bands of the Lyman system are examined. Complete high-resolution experimental reference FUV spectra, together with the model synthetic spectra based on the Abgrall transition probabilities, are presented. An improved calibration standard is obtained, and an accurate calibration of the 3 m spectrometer has been achieved.

  10. Quantum electrodynamics in strong external fields

    International Nuclear Information System (INIS)

    Mueller, B.; Rafelski, J.; Kirsch, J.

    1981-05-01

    We review the theoretical description of quantum electrodynamics in the presence of strong and supercritical fields. In particular, the process of the spontaneous vacuum decay accompanied by the observable positron emission in heavy ion collisions is described. Emphasis is put on the proper formulation of many-body aspects in the framework of quantum field theory. The extension of the theory to the description of Bose fields and many-body effects is presented, and the Klein paradox is resolved. Some implications of the theoretical methods developed here are presented concerning non-abelian gauge theories and the quark confinement puzzle. (orig.)

  11. RE-VISIT OF HST FUV OBSERVATIONS OF THE HOT-JUPITER SYSTEM HD 209458: NO Si iii DETECTION AND THE NEED FOR COS TRANSIT OBSERVATIONS

    International Nuclear Information System (INIS)

    Ballester, G. E.; Ben-Jaffel, L.

    2015-01-01

    The discovery of O i atoms and C ii ions in the upper atmosphere of HD 209458b, made with the Hubble Space Telescope Imaging Spectrograph (STIS) using the G140L grating, showed that these heavy species fill an area comparable to the planet’s Roche lobe. The derived ∼10% transit absorption depths require super-thermal processes and/or supersolar abundances. From subsequent Cosmic Origins Spectrograph (COS) observations, C ii absorption was reported with tentative velocity signatures, and absorption by Si iii ions was also claimed in disagreement with a negative STIS G140L detection. Here, we revisit the COS data set showing a severe limitation in the published results from having contrasted the in-transit spectrum against a stellar spectrum averaged from separate observations, at planetary phases 0.27, 0.72, and 0.49. We find variable stellar Si iii and C ii emissions that were significantly depressed not only during transit but also at phase 0.27 compared to phases 0.72 and 0.49. Their respective off-transit 7.5% and 3.1% flux variations are large compared to their reported 8.2 ± 1.4% and 7.8 ± 1.3% transit absorptions. Significant variations also appear in the stellar line shapes, questioning reported velocity signatures. We furthermore present archive STIS G140M transit data consistent with no Si iii absorption, with a negative result of 1.7 ± 18.7 including ∼15% variability. Silicon may still be present at lower ionization states, in parallel with the recent detection of extended magnesium, as Mg i atoms. In this frame, the firm detection of O i and C ii implying solar or supersolar abundances contradicts the recent inference of potential 20–125× subsolar metallicity for HD 209458b

  12. RE-VISIT OF HST FUV OBSERVATIONS OF THE HOT-JUPITER SYSTEM HD 209458: NO Si iii DETECTION AND THE NEED FOR COS TRANSIT OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Ballester, G. E. [University of Arizona, Dept. of Planetary Sciences, Lunar and Planetary Laboratory, 1541 E University Blvd., Tucson, AZ 85721-0063 (United States); Ben-Jaffel, L., E-mail: gilda@lpl.arizona.edu, E-mail: bjaffel@iap.fr [UPMC Univ. Paris 06, UMR7095, Institut d’Astrophysique de Paris, F-75014 Paris (France)

    2015-05-10

    The discovery of O i atoms and C ii ions in the upper atmosphere of HD 209458b, made with the Hubble Space Telescope Imaging Spectrograph (STIS) using the G140L grating, showed that these heavy species fill an area comparable to the planet’s Roche lobe. The derived ∼10% transit absorption depths require super-thermal processes and/or supersolar abundances. From subsequent Cosmic Origins Spectrograph (COS) observations, C ii absorption was reported with tentative velocity signatures, and absorption by Si iii ions was also claimed in disagreement with a negative STIS G140L detection. Here, we revisit the COS data set showing a severe limitation in the published results from having contrasted the in-transit spectrum against a stellar spectrum averaged from separate observations, at planetary phases 0.27, 0.72, and 0.49. We find variable stellar Si iii and C ii emissions that were significantly depressed not only during transit but also at phase 0.27 compared to phases 0.72 and 0.49. Their respective off-transit 7.5% and 3.1% flux variations are large compared to their reported 8.2 ± 1.4% and 7.8 ± 1.3% transit absorptions. Significant variations also appear in the stellar line shapes, questioning reported velocity signatures. We furthermore present archive STIS G140M transit data consistent with no Si iii absorption, with a negative result of 1.7 ± 18.7 including ∼15% variability. Silicon may still be present at lower ionization states, in parallel with the recent detection of extended magnesium, as Mg i atoms. In this frame, the firm detection of O i and C ii implying solar or supersolar abundances contradicts the recent inference of potential 20–125× subsolar metallicity for HD 209458b.

  13. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.

    1983-01-01

    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  14. Instabilities in strongly coupled plasmas

    CERN Document Server

    Kalman, G J

    2003-01-01

    The conventional Vlasov treatment of beam-plasma instabilities is inappropriate when the plasma is strongly coupled. In the strongly coupled liquid state, the strong correlations between the dust grains fundamentally affect the conditions for instability. In the crystalline state, the inherent anisotropy couples the longitudinal and transverse polarizations, and results in unstable excitations in both polarizations. We summarize analyses of resonant and non-resonant, as well as resistive instabilities. We consider both ion-dust streaming and dust beam-plasma instabilities. Strong coupling, in general, leads to an enhancement of the growth rates. In the crystalline phase, a resonant transverse instability can be excited.

  15. Fraud risks in emissions trading

    International Nuclear Information System (INIS)

    2010-09-01

    The system of emission trading is a complex composed entity with on the one hand a strong environmental component and on the other hand a financial world that hooked on this instrument. In chapter 2 an introduction is provided to the emission trading system. The subsequent chapters elaborate Types of Fraud (Chapter 3), Powers (Chapter 4), and Instruments (Chapter 5). The report shows that various forms of fraud are occurring in emission trading, such as VAT fraud and identity theft. [nl

  16. HAZMAT. I. The evolution of far-UV and near-UV emission from early M stars

    Energy Technology Data Exchange (ETDEWEB)

    Shkolnik, Evgenya L. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Barman, Travis S., E-mail: shkolnik@lowell.edu, E-mail: barman@lpl.arizona.edu [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    2014-10-01

    The spectral energy distribution, variability, and evolution of the high-energy radiation from an M dwarf planet host is crucial in understanding the planet's atmospheric evolution and habitability and in interpreting the planet's spectrum. The star's extreme-UV (EUV), far-UV (FUV), and near-UV (NUV) emission can chemically modify, ionize, and erode the atmosphere over time. This makes determining the lifetime exposure of such planets to stellar UV radiation critical for both the evolution of a planet's atmosphere and our potential to characterize it. Using the early M star members of nearby young moving groups, which sample critical ages in planet formation and evolution, we measure the evolution of the GALEX NUV and FUV flux as a function of age. The median UV flux remains at a 'saturated' level for a few hundred million years, analogous to that observed for X-ray emission. By the age of the Hyades Cluster (650 Myr), we measure a drop in UV flux by a factor of 2-3 followed by a steep drop from old (several Gyrs) field stars. This decline in activity beyond 300 Myr follows roughly t {sup –1}. Despite this clear evolution, there remains a wide range, of 1-2 orders of magnitude, in observed emission levels at every age. These UV data supply the much-needed constraints to M dwarf upper-atmosphere models, which will provide empirically motivated EUV predictions and more accurate age-dependent UV spectra as inputs to planetary photochemical models.

  17. HAZMAT. I. The evolution of far-UV and near-UV emission from early M stars

    International Nuclear Information System (INIS)

    Shkolnik, Evgenya L.; Barman, Travis S.

    2014-01-01

    The spectral energy distribution, variability, and evolution of the high-energy radiation from an M dwarf planet host is crucial in understanding the planet's atmospheric evolution and habitability and in interpreting the planet's spectrum. The star's extreme-UV (EUV), far-UV (FUV), and near-UV (NUV) emission can chemically modify, ionize, and erode the atmosphere over time. This makes determining the lifetime exposure of such planets to stellar UV radiation critical for both the evolution of a planet's atmosphere and our potential to characterize it. Using the early M star members of nearby young moving groups, which sample critical ages in planet formation and evolution, we measure the evolution of the GALEX NUV and FUV flux as a function of age. The median UV flux remains at a 'saturated' level for a few hundred million years, analogous to that observed for X-ray emission. By the age of the Hyades Cluster (650 Myr), we measure a drop in UV flux by a factor of 2-3 followed by a steep drop from old (several Gyrs) field stars. This decline in activity beyond 300 Myr follows roughly t –1 . Despite this clear evolution, there remains a wide range, of 1-2 orders of magnitude, in observed emission levels at every age. These UV data supply the much-needed constraints to M dwarf upper-atmosphere models, which will provide empirically motivated EUV predictions and more accurate age-dependent UV spectra as inputs to planetary photochemical models.

  18. Short proofs of strong normalization

    OpenAIRE

    Wojdyga, Aleksander

    2008-01-01

    This paper presents simple, syntactic strong normalization proofs for the simply-typed lambda-calculus and the polymorphic lambda-calculus (system F) with the full set of logical connectives, and all the permutative reductions. The normalization proofs use translations of terms and types to systems, for which strong normalization property is known.

  19. Strong-back safety latch

    International Nuclear Information System (INIS)

    DeSantis, G.N.

    1995-01-01

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch

  20. Emissions Trading

    NARCIS (Netherlands)

    Woerdman, Edwin; Backhaus, Juergen

    2014-01-01

    Emissions trading is a market-based instrument to achieve environmental targets in a cost-effective way by allowing legal entities to buy and sell emission rights. The current international dissemination and intended linking of emissions trading schemes underlines the growing relevance of this

  1. Emission Facilities - Air Emission Plants

    Data.gov (United States)

    NSGIC Education | GIS Inventory — Represents the Primary Facility type Air Emission Plant (AEP) point features. Air Emissions Plant is a DEP primary facility type related to the Air Quality Program....

  2. Emission inventory; Inventaire des emissions

    Energy Technology Data Exchange (ETDEWEB)

    Fontelle, J.P. [CITEPA, Centre Interprofessionnel Technique d`Etudes de la Pollution Atmospherique, 75 - Paris (France)

    1997-12-31

    Statistics on air pollutant (sulfur dioxide, nitrogen oxides and ammonium) emissions, acid equivalent emissions and their evolution since 1990 in the various countries of Europe and the USA, are presented. Emission data from the industrial, agricultural, transportation and power sectors are given, and comparisons are carried out between countries based on Gnp and population, pollution import/export fluxes and compliance to the previous emission reduction objectives

  3. Electromagnetic radiation from strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Akimoto, K.; Rowland, H.L.; Papadopoulos, K.

    1988-01-01

    A series of computer simulations is reported showing the generation of electromagnetic radiation by strong Langmuir turbulence. The simulations were carried out with a fully electromagnetic 2 1/2 -dimensional fluid code. The radiation process takes place in two stages that reflect the evolution of the electrostatic turbulence. During the first stage while the electrostatic turbulence is evolving from an initial linear wave packet into a planar soliton, the radiation is primarily at ω/sub e/. During the second stage when transverse instabilities lead to the collapse and dissipation of the solitons, 2ω/sub e/ and ω/sub e/ radiation are comparable, and 3ω/sub e/ is also present. The radiation power at ω = 2ω/sub e/ is in good agreement with theoretical predictions for electromagnetic emissions by collapsing solitons

  4. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi

    1988-01-01

    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  5. Strong interactions at high energy

    International Nuclear Information System (INIS)

    Anselmino, M.

    1995-01-01

    Spin effects in strong interaction high energy processes are subtle phenomena which involve both short and long distance physics and test perturbative and non perturbative aspects of QCD. Moreover, depending on quantities like interferences between different amplitudes and relative phases, spin observables always test a theory at a fundamental quantum mechanical level; it is then no surprise that spin data are often difficult to accommodate within the existing models. A report is made on the main issues and contributions discussed in the parallel Session on the open-quote open-quote Strong interactions at high energy close-quote close-quote in this Conference. copyright 1995 American Institute of Physics

  6. Strong-field dissociation dynamics

    International Nuclear Information System (INIS)

    DiMauro, L.F.; Yang, Baorui.

    1993-01-01

    The strong-field dissociation behavior of diatomic molecules is examined under two distinctive physical scenarios. In the first scenario, the dissociation of the isolated hydrogen and deuterium molecular ions is discussed. The dynamics of above-threshold dissociation (ATD) are investigated over a wide range of green and infrared intensities and compared to a dressed-state model. The second situation arises when strong-field neutral dissociation is followed by ionization of the atomic fragments. The study results in a direct measure of the atomic fragment's ac-Stark shift by observing the intensity-dependent shifts in the electron or nuclear fragment kinetic energy. 8 figs., 14 refs

  7. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.

    2007-01-01

    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...... of a discrete random variable....

  8. Strong coupling electroweak symmetry breaking

    International Nuclear Information System (INIS)

    Barklow, T.L.; Burdman, G.; Chivukula, R.S.

    1997-04-01

    The authors review models of electroweak symmetry breaking due to new strong interactions at the TeV energy scale and discuss the prospects for their experimental tests. They emphasize the direct observation of the new interactions through high-energy scattering of vector bosons. They also discuss indirect probes of the new interactions and exotic particles predicted by specific theoretical models

  9. Strong coupling electroweak symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Barklow, T.L. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Burdman, G. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics; Chivukula, R.S. [Boston Univ., MA (United States). Dept. of Physics

    1997-04-01

    The authors review models of electroweak symmetry breaking due to new strong interactions at the TeV energy scale and discuss the prospects for their experimental tests. They emphasize the direct observation of the new interactions through high-energy scattering of vector bosons. They also discuss indirect probes of the new interactions and exotic particles predicted by specific theoretical models.

  10. The colours of strong interaction

    International Nuclear Information System (INIS)

    1995-01-01

    The aim of this session is to draw a consistent framework about the different ways to consider strong interaction. A large part is dedicated to theoretical work and the latest experimental results obtained at the first electron collider HERA are discussed. (A.C.)

  11. Strong cosmic censorship and the strong curvature singularities

    International Nuclear Information System (INIS)

    Krolak, A.

    1987-01-01

    Conditions are given under which any asymptotically simple and empty space-time that has a partial Cauchy surface with an asymptotically simple past is globally hyperbolic. It is shown that this result suggests that the Cauchy horizons of the type occurring in Reissner--Nordstroem and Kerr space-times are unstable. This in turn gives support for the validity of the strong cosmic censorship hypothesis

  12. Strongly Correlated Systems Theoretical Methods

    CERN Document Server

    Avella, Adolfo

    2012-01-01

    The volume presents, for the very first time, an exhaustive collection of those modern theoretical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciates consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as po...

  13. Strongly correlated systems numerical methods

    CERN Document Server

    Mancini, Ferdinando

    2013-01-01

    This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...

  14. Strongly correlated systems experimental techniques

    CERN Document Server

    Mancini, Ferdinando

    2015-01-01

    The continuous evolution and development of experimental techniques is at the basis of any fundamental achievement in modern physics. Strongly correlated systems (SCS), more than any other, need to be investigated through the greatest variety of experimental techniques in order to unveil and crosscheck the numerous and puzzling anomalous behaviors characterizing them. The study of SCS fostered the improvement of many old experimental techniques, but also the advent of many new ones just invented in order to analyze the complex behaviors of these systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. The volume presents a representative collection of the modern experimental techniques specifically tailored for the analysis of strongly correlated systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognize...

  15. Flavour Democracy in Strong Unification

    CERN Document Server

    Abel, S A; Abel, Steven; King, Steven

    1998-01-01

    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of "strong unification". Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged $SU(3)_L\\times SU(3)_R$ family symmetry which illustrates our approach.

  16. String dynamics at strong coupling

    International Nuclear Information System (INIS)

    Hull, C.M.

    1996-01-01

    The dynamics of superstring, supergravity and M-theories and their compactifications are probed by studying the various perturbation theories that emerge in the strong and weak-coupling limits for various directions in coupling constant space. The results support the picture of an underlying non-perturbative theory that, when expanded perturbatively in different coupling constants, gives different perturbation theories, which can be perturbative superstring theories or superparticle theories. The p-brane spectrum is considered in detail and a criterion found to establish which p-branes govern the strong-coupling dynamics. In many cases there are competing conjectures in the literature, and this analysis decides between them. In other cases, new results are found. The chiral 6-dimensional theory resulting from compactifying the type IIB string on K 3 is studied in detail and it is found that certain strong-coupling limits appear to give new theories, some of which hint at the possibility of a 12-dimensional origin. (orig.)

  17. An economic analysis of tradeable emission permits for sulphur dioxide emissions in Europe

    NARCIS (Netherlands)

    Kruitwagen, S.

    1996-01-01

    <strong>7.1 Introductionstrong>
    This study has examined the question of whether a system of tradeable emission permits can contribute to a cost-effective reduction of SO 2 emissions in Europe, taking into account

  18. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Saxena, Siddharth S.; Littlewood, P. B.

    2012-07-01

    This special section is dedicated to the Strongly Correlated Electron Systems Conference (SCES) 2011, which was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 is dedicated to 100 years of superconductivity and covers a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The selected papers derived from invited presentations seek to deepen our understanding of the rich physical phenomena that arise from correlation effects. The focus is on quantum phase transitions, non-Fermi liquid phenomena, quantum magnetism, unconventional superconductivity and metal-insulator transitions. Both experimental and theoretical work is presented. Based on fundamental advances in the understanding of electronic materials, much of 20th century materials physics was driven by miniaturisation and integration in the electronics industry to the current generation of nanometre scale devices. The achievements of this industry have brought unprecedented advances to society and well-being, and no doubt there is much further to go—note that this progress is founded on investments and studies in the fundamentals of condensed matter physics from more than 50 years ago. Nevertheless, the defining challenges for the 21st century will lie in the discovery in science, and deployment through engineering, of technologies that can deliver the scale needed to have an impact on the sustainability agenda. Thus the big developments in nanotechnology may lie not in the pursuit of yet smaller transistors, but in the design of new structures that can revolutionise the performance of solar cells, batteries, fuel cells, light-weight structural materials, refrigeration, water purification, etc. The science presented in the papers of this special section also highlights the underlying interest in energy-dense materials, which

  19. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  20. Strong versions of Bell's theorem

    International Nuclear Information System (INIS)

    Stapp, H.P.

    1994-01-01

    Technical aspects of a recently constructed strong version of Bell's theorem are discussed. The theorem assumes neither hidden variables nor factorization, and neither determinism nor counterfactual definiteness. It deals directly with logical connections. Hence its relationship with modal logic needs to be described. It is shown that the proof can be embedded in an orthodox modal logic, and hence its compatibility with modal logic assured, but that this embedding weakens the theorem by introducing as added assumptions the conventionalities of the particular modal logic that is adopted. This weakening is avoided in the recent proof by using directly the set-theoretic conditions entailed by the locality assumption

  1. Strongly interacting light dark matter

    International Nuclear Information System (INIS)

    Bruggisser, Sebastian; Riva, Francesco; Urbano, Alfredo

    2016-07-01

    In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.

  2. Weak consistency and strong paraconsistency

    Directory of Open Access Journals (Sweden)

    Gemma Robles

    2009-11-01

    Full Text Available In a standard sense, consistency and paraconsistency are understood as, respectively, the absence of any contradiction and as the absence of the ECQ (“E contradictione quodlibet” rule that allows us to conclude any well formed formula from any contradiction. The aim of this paper is to explain the concepts of weak consistency alternative to the standard one, the concepts of paraconsistency related to them and the concept of strong paraconsistency, all of which have been defined by the author together with José M. Méndez.

  3. On the strong CP problem

    Energy Technology Data Exchange (ETDEWEB)

    Dowrick, N.J. (Dept. of Physics, Oxford (United Kingdom)); McDougall, N.A. (National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan))

    1992-07-09

    We show that two well-known solutions to the strong CP problem, the axion and a massless quark, may be understood in terms of the mechanism recently proposed by Samuel where long-range interactions between topological charges may be responsible for the removal of CP violation. We explain how the axion and a QCD meson (identified as the {eta}' if all quarks are massless) suppress fluctuations in global topological charge by almost identical dynamical although the masses, couplings and relevant length scales are very different. Furthermore, we elucidate the precise origin of the {eta}' mass. (orig.).

  4. Scalar strong interaction hadron theory

    CERN Document Server

    Hoh, Fang Chao

    2015-01-01

    The scalar strong interaction hadron theory, SSI, is a first principles' and nonlocal theory at quantum mechanical level that provides an alternative to low energy QCD and Higgs related part of the standard model. The quark-quark interaction is scalar rather than color-vectorial. A set of equations of motion for mesons and another set for baryons have been constructed. This book provides an account of the present state of a theory supposedly still at its early stage of development. This work will facilitate researchers interested in entering into this field and serve as a basis for possible future development of this theory.

  5. Estimation of strong ground motion

    International Nuclear Information System (INIS)

    Watabe, Makoto

    1993-01-01

    Fault model has been developed to estimate a strong ground motion in consideration of characteristics of seismic source and propagation path of seismic waves. There are two different approaches in the model. The first one is a theoretical approach, while the second approach is a semi-empirical approach. Though the latter is more practical than the former to be applied to the estimation of input motions, it needs at least the small-event records, the value of the seismic moment of the small event and the fault model of the large event

  6. Effective lagrangian for strong interactions

    International Nuclear Information System (INIS)

    Jain, P.

    1988-01-01

    We attempt to construct a realistic phenomenological Lagrangian in order to describe strong interactions. This is in general a very complicated problem and we shall explore its various aspects. We first include the vector mesons by writing down the most general chiral invariant terms proportional to the Levi-Civita symbol ε μναβ . These terms involve three unknown coefficients, which are calculated by using the experimental results of strong interaction processes. We then calculate the static nucleon properties by finding the solitonic excitations of this model. The results turn out to be, as is also the case for most other vector-pseudoscalar Lagrangians, better than the Skyrme model but are still somewhat different from the experiments. Another aspect that we shall study is the incorporation of scale anomaly of QCD into the Skyrme model. We thus introduce a scalar glueball in our Lagrangian. Here we find an interesting result that the effective glue field dynamically forms a bag for the soliton. Depending on the values of the parameters, we get either a deep bag or a shallow bag. However by including the scalar meson, we find that to get realistic scalar sector we must have the shallow bag. Finally we show some intriguing connections between the chiral quark model, in which the nucleon is described as a solitonic excitation, and the ordinary potential binding quark model

  7. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Ronning, Filip; Batista, Cristian

    2011-03-01

    Strongly correlated electrons is an exciting and diverse field in condensed matter physics. This special issue aims to capture some of that excitement and recent developments in the field. Given that this issue was inspired by the 2010 International Conference on Strongly Correlated Electron Systems (SCES 2010), we briefly give some history in order to place this issue in context. The 2010 International Conference on Strongly Correlated Electron Systems was held in Santa Fe, New Mexico, a reunion of sorts from the 1989 International Conference on the Physics of Highly Correlated Electron Systems that also convened in Santa Fe. SCES 2010—co-chaired by John Sarrao and Joe Thompson—followed the tradition of earlier conferences, in this century, hosted by Buzios (2008), Houston (2007), Vienna (2005), Karlsruhe (2004), Krakow (2002) and Ann Arbor (2001). Every three years since 1997, SCES has joined the International Conference on Magnetism (ICM), held in Recife (2000), Rome (2003), Kyoto (2006) and Karlsruhe (2009). Like its predecessors, SCES 2010 topics included strongly correlated f- and d-electron systems, heavy-fermion behaviors, quantum-phase transitions, non-Fermi liquid phenomena, unconventional superconductivity, and emergent states that arise from electronic correlations. Recent developments from studies of quantum magnetism and cold atoms complemented the traditional subjects and were included in SCES 2010. 2010 celebrated the 400th anniversary of Santa Fe as well as the birth of astronomy. So what's the connection to SCES? The Dutch invention of the first practical telescope and its use by Galileo in 1610 and subsequent years overturned dogma that the sun revolved about the earth. This revolutionary, and at the time heretical, conclusion required innovative combinations of new instrumentation, observation and mathematics. These same combinations are just as important 400 years later and are the foundation of scientific discoveries that were discussed

  8. Strong Selective Adsorption of Polymers.

    Science.gov (United States)

    Ge, Ting; Rubinstein, Michael

    2015-06-09

    A scaling theory is developed for selective adsorption of polymers induced by the strong binding between specific monomers and complementary surface adsorption sites. By "selective" we mean specific attraction between a subset of all monomers, called "sticky", and a subset of surface sites, called "adsorption sites". We demonstrate that, in addition to the expected dependence on the polymer volume fraction ϕ bulk in the bulk solution, selective adsorption strongly depends on the ratio between two characteristic length scales, the root-mean-square distance l between neighboring sticky monomers along the polymer, and the average distance d between neighboring surface adsorption sites. The role of the ratio l / d arises from the fact that a polymer needs to deform to enable the spatial commensurability between its sticky monomers and the surface adsorption sites for selective adsorption. We study strong selective adsorption of both telechelic polymers with two end monomers being sticky and multisticker polymers with many sticky monomers between sticky ends. For telechelic polymers, we identify four adsorption regimes at l / d 1, we expect that the adsorption layer at exponentially low ϕ bulk consists of separated unstretched loops, while as ϕ bulk increases the layer crosses over to a brush of extended loops with a second layer of weakly overlapping tails. For multisticker chains, in the limit of exponentially low ϕ bulk , adsorbed polymers are well separated from each other. As l / d increases, the conformation of an individual polymer changes from a single-end-adsorbed "mushroom" to a random walk of loops. For high ϕ bulk , adsorbed polymers at small l / d are mushrooms that cover all the adsorption sites. At sufficiently large l / d , adsorbed multisticker polymers strongly overlap. We anticipate the formation of a self-similar carpet and with increasing l / d a two-layer structure with a brush of loops covered by a self-similar carpet. As l / d exceeds the

  9. Strong growth for Queensland mining

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-01

    The Queensland mining industry experienced strong growth during 1989-90 as shown in the latest statistics released by the Department of Resource Industries. The total value of Queensland mineral and energy production rose to a new record of $5.1 billion, an increase of 16.5% on 1988-89 production. A major contributing factor was a 20.9 percent increase in the value of coal production. While the quantity of coal produced rose only 1.1 percent, the substantial increase in the value of coal production is attributable to higher coal prices negotiated for export contracts. In Australian dollar terms coal, gold, lead, zinc and crude oil on average experienced higher international prices than in the previous year. Only copper and silver prices declined. 3 tabs.

  10. Strong moduli stabilization and phenomenology

    CERN Document Server

    Dudas, Emilian; Mambrini, Yann; Mustafayev, Azar; Olive, Keith A

    2013-01-01

    We describe the resulting phenomenology of string theory/supergravity models with strong moduli stabilization. The KL model with F-term uplifting, is one such example. Models of this type predict universal scalar masses equal to the gravitino mass. In contrast, A-terms receive highly suppressed gravity mediated contributions. Under certain conditions, the same conclusion is valid for gaugino masses, which like A-terms, are then determined by anomalies. In such models, we are forced to relatively large gravitino masses (30-1000 TeV). We compute the low energy spectrum as a function of m_{3/2}. We see that the Higgs masses naturally takes values between 125-130 GeV. The lower limit is obtained from the requirement of chargino masses greater than 104 GeV, while the upper limit is determined by the relic density of dark matter (wino-like).

  11. Strongly interacting W's and Z's

    International Nuclear Information System (INIS)

    Gaillard, M.K.

    1984-01-01

    The study focussed primarily on the dynamics of a strongly interacting W, Z(SIW) sector, with the aim of sharpening predictions for total W, Z yield and W, Z multiplicities expected from WW fusion for various scenarios. Specific issues raised in the context of the general problem of modeling SIW included the specificity of the technicolor (or, equivalently, QCD) model, whether or not a composite scalar model can be evaded, and whether the standard model necessarily implies an I = J = O state (≅ Higgs particle) that is relatively ''light'' (M ≤ hundreds of TeV). The consensus on the last issue was that existing arguments are inconclusive. While the author shall briefly address compositeness and alternatives to the technicolor model, quantitative estimates will be of necessity based on technicolor or an extrapolation of pion data

  12. Uniquely Strongly Clean Group Rings

    Institute of Scientific and Technical Information of China (English)

    WANG XIU-LAN

    2012-01-01

    A ring R is called clean if every element is the sum of an idempotent and a unit,and R is called uniquely strongly clean (USC for short) if every element is uniquely the sum of an idempotent and a unit that commute.In this article,some conditions on a ring R and a group G such that RG is clean are given.It is also shown that if G is a locally finite group,then the group ring RG is USC if and only if R is USC,and G is a 2-group.The left uniquely exchange group ring,as a middle ring of the uniquely clean ring and the USC ring,does not possess this property,and so does the uniquely exchange group ring.

  13. Electrophoresis in strong electric fields.

    Science.gov (United States)

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  14. Acoustic emission

    International Nuclear Information System (INIS)

    Straus, A.; Lopez Pumarega, M.I.; Di Gaetano, J.O.; D'Atellis, C.E.; Ruzzante, J.E.

    1990-01-01

    This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

  15. Strong Ideal Convergence in Probabilistic Metric Spaces

    Indian Academy of Sciences (India)

    In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this ...

  16. Strong Statistical Convergence in Probabilistic Metric Spaces

    OpenAIRE

    Şençimen, Celaleddin; Pehlivan, Serpil

    2008-01-01

    In this article, we introduce the concepts of strongly statistically convergent sequence and strong statistically Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong statistical limit points and the strong statistical cluster points of a sequence in this space and investigate the relations between these concepts.

  17. John Strong - 1941-2006

    CERN Multimedia

    2006-01-01

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on 31 July, a few days before his 65th birthday. John started his career and obtained his PhD in a group from Westfield College, initially working on experiments at Rutherford Appleton Laboratory (RAL). From the early 1970s onwards, however, his research was focused on experiments in CERN, with several particularly notable contributions. The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras (a type of television camera) to record the sparks in the spark chambers. This highly automated system allowed Omega to be used in a similar way to bubble chambers. He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems. In these experiments the Westfield group joined forces with Italian colleagues to measure the form factors of the pion and the kaon, and the lifetime of some of the newly discovered charm particles. Such h...

  18. Remnants of strong tidal interactions

    International Nuclear Information System (INIS)

    Mcglynn, T.A.

    1990-01-01

    This paper examines the properties of stellar systems that have recently undergone a strong tidal shock, i.e., a shock which removes a significant fraction of the particles in the system, and where the shocked system has a much smaller mass than the producer of the tidal field. N-body calculations of King models shocked in a variety of ways are performed, and the consequences of the shocks are investigated. The results confirm the prediction of Jaffe for shocked systems. Several models are also run where the tidal forces on the system are constant, simulating a circular orbit around a primary, and the development of tidal radii under these static conditions appears to be a mild process which does not dramatically affect material that is not stripped. The tidal radii are about twice as large as classical formulas would predict. Remnant density profiles are compared with a sample of elliptical galaxies, and the implications of the results for the development of stellar populations and galaxies are considered. 38 refs

  19. Strongly correlated perovskite fuel cells

    Science.gov (United States)

    Zhou, You; Guan, Xiaofei; Zhou, Hua; Ramadoss, Koushik; Adam, Suhare; Liu, Huajun; Lee, Sungsik; Shi, Jian; Tsuchiya, Masaru; Fong, Dillon D.; Ramanathan, Shriram

    2016-06-01

    Fuel cells convert chemical energy directly into electrical energy with high efficiencies and environmental benefits, as compared with traditional heat engines. Yttria-stabilized zirconia is perhaps the material with the most potential as an electrolyte in solid oxide fuel cells (SOFCs), owing to its stability and near-unity ionic transference number. Although there exist materials with superior ionic conductivity, they are often limited by their ability to suppress electronic leakage when exposed to the reducing environment at the fuel interface. Such electronic leakage reduces fuel cell power output and the associated chemo-mechanical stresses can also lead to catastrophic fracture of electrolyte membranes. Here we depart from traditional electrolyte design that relies on cation substitution to sustain ionic conduction. Instead, we use a perovskite nickelate as an electrolyte with high initial ionic and electronic conductivity. Since many such oxides are also correlated electron systems, we can suppress the electronic conduction through a filling-controlled Mott transition induced by spontaneous hydrogen incorporation. Using such a nickelate as the electrolyte in free-standing membrane geometry, we demonstrate a low-temperature micro-fabricated SOFC with high performance. The ionic conductivity of the nickelate perovskite is comparable to the best-performing solid electrolytes in the same temperature range, with a very low activation energy. The results present a design strategy for high-performance materials exhibiting emergent properties arising from strong electron correlations.

  20. Strong seismic ground motion propagation

    International Nuclear Information System (INIS)

    Seale, S.; Archuleta, R.; Pecker, A.; Bouchon, M.; Mohammadioun, G.; Murphy, A.; Mohammadioun, B.

    1988-10-01

    At the McGee Creek, California, site, 3-component strong-motion accelerometers are located at depths of 166 m, 35 m and 0 m. The surface material is glacial moraine, to a depth of 30.5 m, overlying homfels. Accelerations were recorded from two California earthquakes: Round Valley, M L 5.8, November 23, 1984, 18:08 UTC and Chalfant Valley, M L 6.4, July 21, 1986, 14:42 UTC. By separating out the SH components of acceleration, we were able to determine the orientations of the downhole instruments. By separating out the SV component of acceleration, we were able to determine the approximate angle of incidence of the signal at 166 m. A constant phase velocity Haskell-Thomson model was applied to generate synthetic SH seismograms at the surface using the accelerations recorded at 166 m. In the frequency band 0.0 - 10.0 Hz, we compared the filtered synthetic records to the filtered surface data. The onset of the SH pulse is clearly seen, as are the reflections from the interface at 30.5 m. The synthetic record closely matches the data in amplitude and phase. The fit between the synthetic accelerogram and the data shows that the seismic amplification at the surface is a result of the contrast of the impedances (shear stiffnesses) of the near surface materials

  1. The characterization of the high-frequency vibronic contributions to the 77 K emission spectra of ruthenium-am(m)ine-bipyridyl complexes, their attenuation with decreasing energy gaps, and the implications of strong electronic coupling for inverted-region electron transfer.

    Science.gov (United States)

    Xie, Puhui; Chen, Yuan-Jang; Uddin, Md Jamal; Endicott, John F

    2005-06-02

    The 77 K emission spectra of a series of [Ru(Am)6-2n(bpy)n]2+ complexes (n = 1-3) have been determined in order to evaluate the effects of appreciable excited state (e)/ground state (g) configurational mixing on the properties of simple electron-transfer systems. The principal focus is on the vibronic contributions, and the correlated distortions of the bipyridine ligand in the emitting MLCT excited state. To address the issues that are involved, the emission band shape at 77 K is interpreted as the sum of a fundamental component, corresponding to the {e,0'} --> {g,0} transition, and progressions in the ground-state vibrational modes that correlate with the excited-state distortion. Literature values of the vibrational parameters determined from the resonance-Raman (rR) for [Ru(NH3)4bpy]2+ and [Ru(bpy)3]2+ are used to model the emission spectra and to evaluate the spectral analysis. The Gaussian fundamental component with an energy Ef and bandwidth Deltanu1/2 is deconvoluted from the observed emission spectrum. The first-, second-, and third-order terms in the progressions of the vibrational modes that contribute to the band shape are evaluated as the sums of Gaussian-shaped contributions of width Deltanu1/2. The fundamental and the rR parameters give an excellent fit of the observed emission spectrum of [Ru(NH3)4bpy]2+, but not as good for the [Ru(bpy)3]2+ emission spectrum probably because the Franck-Condon excited state probed by the rR is different in symmetry from the emitting MLCT excited state. Variations in vibronic contributions for the series of complexes are evaluated in terms of reorganizational energy profiles (emreps, Lambdax) derived from the observed spectra, and modeled using the rR parameters. This modeling demonstrates that most of the intensity of the vibronic envelopes obtained from the frozen solution emission spectra arises from the overlapping of first-order vibronic contributions of significant bandwidth with additional convoluted

  2. Strongly interacting photons and atoms

    International Nuclear Information System (INIS)

    Alge, W.

    1999-05-01

    This thesis contains the main results of the research topics I have pursued during the my PhD studies at the University of Innsbruck and partly in collaboration with the Institut d' Optique in Orsay, France. It is divided into three parts. The first and largest part discusses the possibility of using strong standing waves as a tool to cool and trap neutral atoms in optical cavities. This is very important in the field of nonlinear optics where several successful experiments with cold atoms in cavities have been performed recently. A discussion of the optical parametric oscillator in a regime where the nonlinearity dominates the evolution is the topic of the second part. We investigated mainly the statistical properties of the cavity output of the three interactive cavity modes. Very recently a system has been proposed which promises fantastic properties. It should exhibit a giant Kerr nonlinearity with negligible absorption thus leading to a photonic turnstile device based on cold atoms in cavity. We have shown that this model suffers from overly simplistic assumptions and developed several more comprehensive approaches to study the behavior of this system. Apart from the division into three parts of different contents the thesis is divided into publications, supplements and invisible stuff. The intention of the supplements is to reach researchers which work in related areas and provide them with more detailed information about the concepts and the numerical tools we used. It is written especially for diploma and PhD students to give them a chance to use the third part of our work which is actually the largest one. They consist of a large number of computer programs we wrote to investigate the behavior of the systems in parameter regions where no hope exists to solve the equations analytically. (author)

  3. Topics in strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Skoric, M.M.

    1981-01-01

    This thesis discusses certain aspects of the turbulence of a fully ionised non-isothermal plasma dominated by the Langmuir mode. Some of the basic properties of strongly turbulent plasmas are reviewed. In particular, interest is focused on the state of Langmuir turbulence, that is the turbulence of a simple externally unmagnetized plasma. The problem of the existence and dynamics of Langmuir collapse is discussed, often met as a non-linear stage of the modulational instability in the framework of the Zakharov equations (i.e. simple time-averaged dynamical equations). Possible macroscopic consequences of such dynamical turbulent models are investigated. In order to study highly non-linear collapse dynamics in its advanced stage, a set of generalized Zakharov equations are derived. Going beyond the original approximation, the author includes the effects of higher electron non-linearities and a breakdown of slow-timescale quasi-neutrality. He investigates how these corrections may influence the collapse stabilisation. Recently, it has been realised that the modulational instability in a Langmuir plasma will be accompanied by the collisionless-generation of a slow-timescale magnetic field. Accordingly, a novel physical situation has emerged which is investigated in detail. The stability of monochromatic Langmuir waves in a self-magnetized Langmuir plasma, is discussed, and the existence of a novel magneto-modulational instability shown. The wave collapse dynamics is investigated and a physical interpretation of the basic results is given. A problem of the transient analysis of an interaction of time-dependent electromagnetic pulses with linear cold plasma media is investigated. (Auth.)

  4. Promoting Strong Written Communication Skills

    Science.gov (United States)

    Narayanan, M.

    2015-12-01

    The reason that an improvement in the quality of technical writing is still needed in the classroom is due to the fact that universities are facing challenging problems not only on the technological front but also on the socio-economic front. The universities are actively responding to the changes that are taking place in the global consumer marketplace. Obviously, there are numerous benefits of promoting strong written communication skills. They can be summarized into the following six categories. First, and perhaps the most important: The University achieves learner satisfaction. The learner has documented verbally, that the necessary knowledge has been successfully acquired. This results in learner loyalty that in turn will attract more qualified learners.Second, quality communication lowers the cost per pupil, consequently resulting in increased productivity backed by a stronger economic structure and forecast. Third, quality communications help to improve the cash flow and cash reserves of the university. Fourth, having high quality communication enables the university to justify the need for high costs of tuition and fees. Fifth, better quality in written communication skills result in attracting top-quality learners. This will lead to happier and satisfied learners, not to mention greater prosperity for the university as a whole. Sixth, quality written communication skills result in reduced complaints, thus meaning fewer hours spent on answering or correcting the situation. The University faculty and staff are thus able to devote more time on scholarly activities, meaningful research and productive community service. References Boyer, Ernest L. (1990). Scholarship reconsidered: Priorities of the Professorate.Princeton, NJ: Carnegie Foundation for the Advancement of Teaching. Hawkins, P., & Winter, J. (1997). Mastering change: Learning the lessons of the enterprise.London: Department for Education and Employment. Buzzel, Robert D., and Bradley T. Gale. (1987

  5. White light emission from engineered silicon carbide

    DEFF Research Database (Denmark)

    Ou, Haiyan

    Silicon carbide (SiC) is a wide indirect bandgap semiconductor. The light emission efficiency is low in nature. But this material has very unique physical properties like good thermal conductivity, high break down field etc in addition to its abundance. Therefore it is interesting to engineer its...... light emission property so that to take fully potential applications of this material. In this talk, two methods, i.e. doping SiC heavily by donor-acceptor pairs and making SiC porous are introduced to make light emission from SiC. By co-doping SiC with nitrogen and boron heavily, strong yellow emission...... is demonstrated. After optimizing the passivation conditions, strong blue-green emission from porous SiC is demonstrated as well. When combining the yellow emission from co-doped SiC and blue-green from porous SiC, a high color rendering index white light source is achieved....

  6. Sensitivity of upper atmospheric emissions calculations to solar/stellar UV flux

    Directory of Open Access Journals (Sweden)

    Barthelemy Mathieu

    2014-01-01

    Full Text Available The solar UV (UltraViolet flux, especially the EUV (Extreme UltraViolet and FUV (Far UltraViolet components, is one of the main energetic inputs for planetary upper atmospheres. It drives various processes such as ionization, or dissociation which give rise to upper atmospheric emissions, especially in the UV and visible. These emissions are one of the main ways to investigate the upper atmospheres of planets. However, the uncertainties in the flux measurement or modeling can lead to biased estimates of fundamental atmospheric parameters, such as concentrations or temperatures in the atmospheres. We explore the various problems that can be identified regarding the uncertainties in solar/stellar UV flux by considering three examples. The worst case appears when the solar reflection component is dominant in the recorded spectrum as is seen for outer solar system measurements from HST (Hubble Space Telescope. We also show that the estimation of some particular line parameters (intensity and shape, especially Lyman α, is crucial, and that both total intensity and line profile are useful. In the case of exoplanets, the problem is quite critical since the UV flux of their parent stars is often very poorly known.

  7. Intensity of emission lines of the quiescent solar corona: comparison between calculated and observed values

    Science.gov (United States)

    Krissinel, Boris

    2018-03-01

    The paper reports the results of calculations of the center-to-limb intensity of optically thin line emission in EUV and FUV wavelength ranges. The calculations employ a multicomponent model for the quiescent solar corona. The model includes a collection of loops of various sizes, spicules, and free (inter-loop) matter. Theoretical intensity values are found from probabilities of encountering parts of loops in the line of sight with respect to the probability of absence of other coronal components. The model uses 12 loops with sizes from 3200 to 210000 km with different values of rarefaction index and pressure at the loop base and apex. The temperature at loop apices is 1 400 000 K. The calculations utilize the CHIANTI database. The comparison between theoretical and observed emission intensity values for coronal and transition region lines obtained by the SUMER, CDS, and EIS telescopes shows quite satisfactory agreement between them, particularly for the solar disk center. For the data acquired above the limb, the enhanced discrepancies after the analysis refer to errors in EIS measurements.

  8. Pulsar kicks from majoron emission

    International Nuclear Information System (INIS)

    Farzan, Yasaman; Gelmini, Graciela; Kusenko, Alexander

    2005-01-01

    We show that majoron emission from a hot nascent neutron star can be anisotropic in the presence of a strong magnetic field. If majorons carry a non-negligible fraction of the supernova energy, the resulting recoil velocity of a neutron star can explain the observed velocities of pulsars

  9. Russia needs a strong counterpart

    International Nuclear Information System (INIS)

    Slovak, K.; Marcan, P.

    2008-01-01

    In this paper an interview with the head of OMV, Wolfgang Ruttenstorfer is published. There is extract from this interview: Q: There have been attempts to take over MOL for a quite long time. Do you think you can still succeed? Since the beginning we kept saying that this would not happen from one day to another. But it may take two to three years. But we are positive that it is justified. Q: Resistance from MOL and the Hungarian government is strong. We have tried to persuade the Hungarian government. We offered them a split company management. A part of the management would be in Budapest. We would locate the management of the largest division - the refinery, there. And of course only the best could be part of the management. We would not nominate people according to their nationality, it would not matter whether the person was Austrian, Hungarian or Slovak. We want a Central European company, not Hungarian, Romanian or Slovak company. Q: Would the transaction still be attractive if, because of pressure exercised by Brussels, you had to sell Slovnaft or your refinery in Szazhalobatta? We do not intend to sell any refineries. Q: Rumours are spreading that the Commission may ask you to sell a refinery? We do not want to speculate. Let us wait and see what happens. We do not want to sell refineries. Q: It is said that OMV is coordinating or at least consulting its attempts to acquire MOL with Gazprom. There are many rumours in Central Europe. But I can tell you this is not true. We are interested in this merger because we feel the increasing pressure exercised by Kazakhstan and Russia. We, of course, have a good relationship with Gazprom which we have had enjoyed for over forty years. As indeed Slovakia has. Q: A few weeks ago Austrian daily Wirtschaftsblatt published an article about Gazprom's interest in OMV shares. That is gossip that is more than ten years' old. Similarly to the rumours that Gazprom is a shareholder of MOL. There are no negotiations with Gazprom

  10. Axion production from Landau quantization in the strong magnetic field of magnetars

    Science.gov (United States)

    Maruyama, Tomoyuki; Balantekin, A. Baha; Cheoun, Myung-Ki; Kajino, Toshitaka; Mathews, Grant J.

    2018-04-01

    We utilize an exact quantum calculation to explore axion emission from electrons and protons in the presence of the strong magnetic field of magnetars. The axion is emitted via transitions between the Landau levels generated by the strong magnetic field. The luminosity of axions emitted by protons is shown to be much larger than that of electrons and becomes stronger with increasing matter density. Cooling by axion emission is shown to be much larger than neutrino cooling by the Urca processes. Consequently, axion emission in the crust may significantly contribute to the cooling of magnetars. In the high-density core, however, it may cause heating of the magnetar.

  11. Spontaneous light emission in complex nanostructures

    Science.gov (United States)

    Blanco, L. A.; García de Abajo, F. J.

    2004-05-01

    The spontaneous emission of an excited atom surrounded by different materials is studied in the framework of a semiclassical approach, where the transition dipole moment acts as the source of the emission field. The emission in the presence of semiinfinite media, metallic nanorings, spheres, gratings, and other complex geometries is investigated. Strong emission enhancement effects are obtained in some of these geometries associated to the excitation of plasmons (e.g., in nanorings or spheres). Furthermore, the emission is shown to take place only along narrow angular distributions when the atom is located inside a low-index dielectric and near its planar surface, or when metallic nanogratings are employed at certain resonant wave lengths. In particular, axially symmetric gratings made of real silver metal are considered, and both emission rate enhancement and focused far-field emission are achieved simultaneously when the grating is decorated with further nanostructures.

  12. High-latitude electromagnetic and particle energy flux during an event with sustained strongly northward IMF

    Directory of Open Access Journals (Sweden)

    H. Korth

    2005-06-01

    Full Text Available We present a case study of a prolonged interval of strongly northward orientation of the interplanetary magnetic field on 16 July 2000, 16:00-19:00 UT to characterize the energy exchange between the magnetosphere and ionosphere for conditions associated with minimum solar wind-magnetosphere coupling. With reconnection occurring tailward of the cusp under northward IMF conditions, the reconnection dynamo should be separated from the viscous dynamo, presumably driven by the Kelvin-Helmholtz (KH instability. Thus, these conditions are also ideal for evaluating the contribution of a viscous interaction to the coupling process. We derive the two-dimensional distribution of the Poynting vector radial component in the northern sunlit polar ionosphere from magnetic field observations by the constellation of Iridium satellites together with drift meter and magnetometer observations from the Defense Meteorological Satellite Program (DMSP F13 and F15 satellites. The electromagnetic energy flux is then compared with the particle energy flux obtained from auroral images taken by the far-ultraviolet (FUV instrument on the Imager for Magnetopause to Aurora Global Exploration (IMAGE spacecraft. The electromagnetic energy input to the ionosphere of 51 GW calculated from the Iridium/DMSP observations is eight times larger than the 6 GW due to particle precipitation all poleward of 78° MLAT. This result indicates that the energy transport is significant, particularly as it is concentrated in a small region near the magnetic pole, even under conditions traditionally considered to be quiet and is dominated by the electromagnetic flux. We estimate the contributions of the high and mid-latitude dynamos to both the Birkeland currents and electric potentials finding that high-latitude reconnection accounts for 0.8 MA and 45kV while we attribute <0.2MA and ~5kV to an interaction at lower latitudes having the sense of a viscous interaction. Given that these

  13. STRONG FIELD EFFECTS ON PULSAR ARRIVAL TIMES: GENERAL ORIENTATIONS

    International Nuclear Information System (INIS)

    Wang Yan; Creighton, Teviet; Price, Richard H.; Jenet, Frederick A.

    2009-01-01

    A pulsar beam passing close to a black hole can provide a probe of very strong gravitational fields even if the pulsar itself is not in a strong field region. In the case that the spin of the hole can be ignored, we have previously shown that all strong field effects on the beam can be understood in terms of two 'universal' functions: F(φ in ) and T(φ in ) of the angle of beam emission φ in ; these functions are universal in that they depend only on a single parameter, the pulsar/black hole distance from which the beam is emitted. Here we apply this formalism to general pulsar-hole-observer geometries, with arbitrary alignment of the pulsar spin axis and arbitrary pulsar beam direction and angular width. We show that the analysis of the observational problem has two distinct elements: (1) the computation of the location and trajectory of an observer-dependent 'keyhole' direction of emission in which a signal can be received by the observer; and (2) the determination of an annulus that represents the set of directions containing beam energy. Examples of each are given along with an example of a specific observational scenario.

  14. Electromagnetic processes in strong crystalline fields - NA63 Status Report

    CERN Document Server

    Ugerhoj, Ulrik

    2009-01-01

    Results obtained in the framework of the NA63 experiment cite{Ande05} at CERN are reported. Analysis of the trident production in the strong crystalline fields of single Ge crystals is completed. Yields in the random ('amorphous') orientation are in good agreement with calculations, and in the aligned case the production is enhanced by about a factor 3 compared to a Ge amorphous material. Results on the formation lengths of several microns for the production of GeV photons from ultrarelativistic electrons have been published. In 2008 we performed a measurement of resonance phenomena in structured targets and studied a possible change in restricted energy loss in thin solid state detectors, for sufficiently high values of the Lorentz factor. The plans for 2009 are to study the 'semi-bare electron' from radiation emission in thin targets and to study the spin-flip mechanisms in radiation emission, relevant for beamstrahlung phenomena in future linear colliders such as CLIC.

  15. ORIGIN OF THE DIFFUSE, FAR ULTRAVIOLET EMISSION IN THE INTERARM REGIONS OF M101

    International Nuclear Information System (INIS)

    Crocker, Alison F.; Chandar, Rupali; Calzetti, Daniela; Holwerda, Benne Willem; Leitherer, Claus; Popescu, Cristina; Tuffs, R. J.

    2015-01-01

    We present images from the Solar Blind Channel on the Hubble Space Telescope that resolve hundreds of far-ultraviolet (FUV) emitting stars in two ∼1 kpc 2 interarm regions of the grand-design spiral M101. The luminosity functions of these stars are compared with predicted distributions from simple star formation histories, and are best reproduced when the star formation rate has recently declined (past 10–50 Myr). This pattern is consistent with stars forming within spiral arms and then streaming into the interarm regions. We measure the diffuse FUV surface brightness after subtracting all of the detected stars, clusters, and background galaxies. A residual flux is found for both regions, which can be explained by a mix of stars below our detection limit and scattered FUV light. The amount of scattered light required is much larger for the region immediately adjacent to a spiral arm, a bright source of FUV photons

  16. Marshmallowing of nanopillar arrays by field emission

    International Nuclear Information System (INIS)

    Qin Hua; Kim, Hyun-Seok; Blick, Robert H.

    2010-01-01

    We fabricated nanoscale field electron emitters formed by highly-doped silicon nanopillars on a silicon membrane. Electron-beam induced deposition of carbon-based contaminants is employed as a probe of the spatial activity of electron emission from the nanopillars. In stark contrast to the general assumption that field emission only occurs at the tips of nanoscale emitters, we found strong emission from the sidewalls of the nanopillars. This is revealed by the deposition of carbon contaminants on these sidewalls, so that the nanopillars finally resemble marshmallows. We conclude that field emission from nanostructured surfaces is more intricate than previously expected.

  17. Marshmallowing of nanopillar arrays by field emission

    International Nuclear Information System (INIS)

    Park, J; Qin, H; Kim, H-S; Blick, R H

    2009-01-01

    We have fabricated mechanically flexible field electron emitters formed by highly-doped silicon nanopillars on a silicon membrane. Electron beam induced deposition of carbon-based contaminants is employed to probe the spatial activity of electron emission from the nanopillars. The experimental configuration provides a powerful tool to investigate the physics of the field electron emission (FEE). In contrast to the general assumption that field emission only occurs at the tips of nanoscale emitters, we found that the emission from the nanopillars' sidewalls is as strong as from their tips.

  18. Photon-dominated region modeling of the [C I], [C II], and CO Line Emission From A Boundary In The Taurus molecular cloud

    Energy Technology Data Exchange (ETDEWEB)

    Orr, Matthew E. [Physics and Astronomy Department, University of Southern California, Los Angeles, CA 90089 (United States); Pineda, Jorge L.; Goldsmith, Paul F. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States)

    2014-11-01

    We present [C I] and [C II] observations of a linear edge region in the Taurus molecular cloud, and model this region as a cylindrically symmetric photon-dominated region (PDR) exposed to a low-intensity UV radiation field. The sharp, long profile of the linear edge makes it an ideal case to test PDR models and determine cloud parameters. We compare observations of the [C I], {sup 3} P {sub 1} → {sup 3} P {sub 0} (492 GHz), [C I] {sup 3} P {sub 2} → {sup 3} P {sub 1} (809 GHz), and [C II] {sup 2} P {sub 3/2} → {sup 2} P {sub 1/2} (1900 GHz) transitions, as well as the lowest rotational transitions of {sup 12}CO and {sup 13}CO, with line intensities produced by the RATRAN radiative transfer code from the results of the Meudon PDR code. We constrain the density structure of the cloud by fitting a cylindrical density function to visual extinction data. We study the effects of variation of the FUV field, {sup 12}C/{sup 13}C isotopic abundance ratio, sulfur depletion, cosmic ray ionization rate, and inclination of the filament relative to the sky-plane on the chemical network of the PDR model and resulting line emission. We also consider the role of suprathermal chemistry and density inhomogeneities. We find good agreement between the model and observations, and that the integrated line intensities can be explained by a PDR model with an external FUV field of 0.05 G {sub 0}, a low ratio of {sup 12}C to {sup 13}C ∼43, a highly depleted sulfur abundance (by a factor of at least 50), a cosmic ray ionization rate (3-6) × 10{sup –17} s{sup –1}, and without significant effects from inclination, clumping or suprathermal chemistry.

  19. Microscopic modeling of photoluminescence of strongly disordered semiconductors

    International Nuclear Information System (INIS)

    Bozsoki, P.; Kira, M.; Hoyer, W.; Meier, T.; Varga, I.; Thomas, P.; Koch, S.W.

    2007-01-01

    A microscopic theory for the luminescence of ordered semiconductors is modified to describe photoluminescence of strongly disordered semiconductors. The approach includes both diagonal disorder and the many-body Coulomb interaction. As a case study, the light emission of a correlated plasma is investigated numerically for a one-dimensional two-band tight-binding model. The band structure of the underlying ordered system is assumed to correspond to either a direct or an indirect semiconductor. In particular, luminescence and absorption spectra are computed for various levels of disorder and sample temperature to determine thermodynamic relations, the Stokes shift, and the radiative lifetime distribution

  20. Flaw identification using acoustic emission

    International Nuclear Information System (INIS)

    Woodward, B.; McDonald, N.R.

    1975-01-01

    Acoustic emission 'signatures' contain information about the fine structure of metallurgical source events and their interpretation may provide a means of assessing the severity of internal flaws as well as surface flaws. The ultimate aim of this research on signature analysis is to develop a real time non-destructive testing technique having the capability of flaw recognition as well as flaw location in nuclear reactor components and structures under stress. Thus the requisite, unlike that in most acoustic emission work to date, is for a technique which affords discrimination between acoustic emission from different types of flaws propagating simultaneously. The approach described here requires detailed analysis of the emission signatures in terms of a specific statistical parameter, energy spectral density. In order to realise the full inspection potential of acoustic emission monitoring data obtained from zirconium and steel testpieces have been correlated with metallurgical condition and mechanical behaviour, since the nature of emission signatures is strongly affected by the physical characteristics and internal structure of the material. (Auth.)

  1. Strong Bisimilarity of Simple Process Algebras

    DEFF Research Database (Denmark)

    Srba, Jirí

    2003-01-01

    We study bisimilarity and regularity problems of simple process algebras. In particular, we show PSPACE-hardness of the following problems: (i) strong bisimilarity of Basic Parallel Processes (BPP), (ii) strong bisimilarity of Basic Process Algebra (BPA), (iii) strong regularity of BPP, and (iv......) strong regularity of BPA. We also demonstrate NL-hardness of strong regularity problems for the normed subclasses of BPP and BPA. Bisimilarity problems of simple process algebras are introduced in a general framework of process rewrite systems, and a uniform description of the new techniques used...

  2. Application of strong phosphoric acid to radiochemistry

    International Nuclear Information System (INIS)

    Terada, Kikuo

    1977-01-01

    Not only inorganic and organic compounds but also natural substrances, such as accumulations in soil, are completely decomposed and distilled by heating with strong phosphoric acid for 30 to 50 minutes. As applications of strong phosphoric acid to radiochemistry, determination of uranium and boron by use of solubilization effect of this substance, titration of uranyl ion by use of sulfuric iron (II) contained in this substance, application to tracer experiment, and determination of radioactive ruthenium in environmental samples are reviewed. Strong phosphoric acid is also applied to activation analysis, for example, determination of N in pyrographite with iodate potassium-strong phosphoric acid method, separation of Os and Ru with sulfuric cerium (IV) - strong phosphoric acid method or potassium dechromate-strong phosphoric acid method, analysis of Se, As and Sb rocks and accumulations with ammonium bromide, sodium chloride and sodium bromide-strong phosphoric acid method. (Kanao, N.)

  3. RADIO POLARIMETRY SIGNATURES OF STRONG MAGNETIC TURBULENCE IN SUPERNOVA REMNANTS

    International Nuclear Information System (INIS)

    Stroman, Wendy; Pohl, Martin

    2009-01-01

    We discuss the emission and transport of polarized radio-band synchrotron radiation near the forward shocks of young shell-type supernova remnants, for which X-ray data indicate a strong amplification of turbulent magnetic field. Modeling the magnetic turbulence through the superposition of waves, we calculate the degree of polarization and the magnetic polarization direction which is at 90 deg. to the conventional electric polarization direction. We find that isotropic strong turbulence will produce weakly polarized radio emission even in the absence of internal Faraday rotation. If anisotropy is imposed on the magnetic-field structure, the degree of polarization can be significantly increased, provided internal Faraday rotation is inefficient. Both for shock compression and a mixture with a homogeneous field, the increase in polarization degree goes along with a fairly precise alignment of the magnetic-polarization angle with the direction of the dominant magnetic-field component, implying tangential magnetic polarization at the rims in the case of shock compression. We compare our model with high-resolution radio polarimetry data of Tycho's remnant. Using the absence of internal Faraday rotation we find a soft limit for the amplitude of magnetic turbulence, δB ∼ 0 . An alternative viable scenario involves anisotropic turbulence with stronger amplitudes in the radial direction, as was observed in recent Magnetohydrodynamics simulations of shocks propagating through a medium with significant density fluctuations.

  4. Strong Neutron Pairing in core+4n Nuclei.

    Science.gov (United States)

    Revel, A; Marqués, F M; Sorlin, O; Aumann, T; Caesar, C; Holl, M; Panin, V; Vandebrouck, M; Wamers, F; Alvarez-Pol, H; Atar, L; Avdeichikov, V; Beceiro-Novo, S; Bemmerer, D; Benlliure, J; Bertulani, C A; Boillos, J M; Boretzky, K; Borge, M J G; Caamaño, M; Casarejos, E; Catford, W N; Cederkäll, J; Chartier, M; Chulkov, L; Cortina-Gil, D; Cravo, E; Crespo, R; Datta Pramanik, U; Díaz Fernández, P; Dillmann, I; Elekes, Z; Enders, J; Ershova, O; Estradé, A; Farinon, F; Fraile, L M; Freer, M; Galaviz, D; Geissel, H; Gernhäuser, R; Golubev, P; Göbel, K; Hagdahl, J; Heftrich, T; Heil, M; Heine, M; Heinz, A; Henriques, A; Ignatov, A; Johansson, H T; Jonson, B; Kahlbow, J; Kalantar-Nayestanaki, N; Kanungo, R; Kelic-Heil, A; Knyazev, A; Kröll, T; Kurz, N; Labiche, M; Langer, C; Le Bleis, T; Lemmon, R; Lindberg, S; Machado, J; Marganiec, J; Movsesyan, A; Nacher, E; Najafi, M; Nilsson, T; Nociforo, C; Paschalis, S; Perea, A; Petri, M; Pietri, S; Plag, R; Reifarth, R; Ribeiro, G; Rigollet, C; Röder, M; Rossi, D; Savran, D; Scheit, H; Simon, H; Syndikus, I; Taylor, J T; Tengblad, O; Thies, R; Togano, Y; Velho, P; Volkov, V; Wagner, A; Weick, H; Wheldon, C; Wilson, G; Winfield, J S; Woods, P; Yakorev, D; Zhukov, M; Zilges, A; Zuber, K

    2018-04-13

    The emission of neutron pairs from the neutron-rich N=12 isotones ^{18}C and ^{20}O has been studied by high-energy nucleon knockout from ^{19}N and ^{21}O secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment-n-n correlations shows that the decay ^{19}N(-1p)^{18}C^{*}→^{16}C+n+n is clearly dominated by direct pair emission. The two-neutron correlation strength, the largest ever observed, suggests the predominance of a ^{14}C core surrounded by four valence neutrons arranged in strongly correlated pairs. On the other hand, a significant competition of a sequential branch is found in the decay ^{21}O(-1n)^{20}O^{*}→^{18}O+n+n, attributed to its formation through the knockout of a deeply bound neutron that breaks the ^{16}O core and reduces the number of pairs.

  5. Strong Stationary Duality for Diffusion Processes

    OpenAIRE

    Fill, James Allen; Lyzinski, Vince

    2014-01-01

    We develop the theory of strong stationary duality for diffusion processes on compact intervals. We analytically derive the generator and boundary behavior of the dual process and recover a central tenet of the classical Markov chain theory in the diffusion setting by linking the separation distance in the primal diffusion to the absorption time in the dual diffusion. We also exhibit our strong stationary dual as the natural limiting process of the strong stationary dual sequence of a well ch...

  6. Strongly correlating liquids and their isomorphs

    OpenAIRE

    Pedersen, Ulf R.; Gnan, Nicoletta; Bailey, Nicholas P.; Schröder, Thomas B.; Dyre, Jeppe C.

    2010-01-01

    This paper summarizes the properties of strongly correlating liquids, i.e., liquids with strong correlations between virial and potential energy equilibrium fluctuations at constant volume. We proceed to focus on the experimental predictions for strongly correlating glass-forming liquids. These predictions include i) density scaling, ii) isochronal superposition, iii) that there is a single function from which all frequency-dependent viscoelastic response functions may be calculated, iv) that...

  7. Atom collisions in a strong electromagnetic field

    International Nuclear Information System (INIS)

    Smirnov, V.S.; Chaplik, A.V.

    1976-01-01

    It is shown that the long-range part of interatomic interaction is considerably altered in a strong electromagnetic field. Instead of the van der Waals law the potential asymptote can best be described by a dipole-dipole R -3 law. Impact broadening and the line shift in a strong nonresonant field are calculated. The possibility of bound states of two atoms being formed in a strong light field is discussed

  8. On the Strong Direct Summand Conjecture

    Science.gov (United States)

    McCullough, Jason

    2009-01-01

    In this thesis, our aim is the study the Vanishing of Maps of Tor Conjecture of Hochster and Huneke. We mainly focus on an equivalent characterization called the Strong Direct Summand Conjecture, due to N. Ranganathan. Our results are separated into three chapters. In Chapter 3, we prove special cases of the Strong Direct Summand Conjecture in…

  9. Physics challenges in the strong interactions

    International Nuclear Information System (INIS)

    Ellis, S.D.

    1992-01-01

    The study of strong interactions is now a mature field for which scientist now know that the correct underlying theory is QCD. Here, an overview of the challenges to be faced in the area of the strong interactions during the 1990's is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders

  10. Physics challenges in the strong interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, S.D. [Univ. of Washington, Seattle (United States)

    1992-12-31

    The study of strong interactions is now a mature field for which scientist now know that the correct underlying theory is QCD. Here, an overview of the challenges to be faced in the area of the strong interactions during the 1990`s is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders.

  11. Theoretical studies of strongly correlated fermions

    Energy Technology Data Exchange (ETDEWEB)

    Logan, D [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    Strongly correlated fermions are investigated. An understanding of strongly correlated fermions underpins a diverse range of phenomena such as metal-insulator transitions, high-temperature superconductivity, magnetic impurity problems and the properties of heavy-fermion systems, in all of which local moments play an important role. (author).

  12. The strong reflecting property and Harrington's Principle

    OpenAIRE

    Cheng, Yong

    2015-01-01

    In this paper we characterize the strong reflecting property for $L$-cardinals for all $\\omega_n$, characterize Harrington's Principle $HP(L)$ and its generalization and discuss the relationship between the strong reflecting property for $L$-cardinals and Harrington's Principle $HP(L)$.

  13. Strong Nash Equilibria and the Potential Maimizer

    NARCIS (Netherlands)

    van Megen, F.J.C.; Facchini, G.; Borm, P.E.M.; Tijs, S.H.

    1996-01-01

    A class of non cooperative games characterized by a `congestion e ect' is studied, in which there exists a strong Nash equilibrium, and the set of Nash equilibria, the set of strong Nash equilibria and the set of strategy pro les maximizing the potential function coincide.The structure of the class

  14. Large N baryons, strong coupling theory, quarks

    International Nuclear Information System (INIS)

    Sakita, B.

    1984-01-01

    It is shown that in QCD the large N limit is the same as the static strong coupling limit. By using the static strong coupling techniques some of the results of large N baryons are derived. The results are consistent with the large N SU(6) static quark model. (author)

  15. The lambda sigma calculus and strong normalization

    DEFF Research Database (Denmark)

    Schack-Nielsen, Anders; Schürmann, Carsten

    Explicit substitution calculi can be classified into several dis- tinct categories depending on whether they are confluent, meta-confluent, strong normalization preserving, strongly normalizing, simulating, fully compositional, and/or local. In this paper we present a variant of the λσ-calculus, ...

  16. Optimization of strong and weak coordinates

    NARCIS (Netherlands)

    Swart, M.; Bickelhaupt, F.M.

    2006-01-01

    We present a new scheme for the geometry optimization of equilibrium and transition state structures that can be used for both strong and weak coordinates. We use a screening function that depends on atom-pair distances to differentiate strong coordinates from weak coordinates. This differentiation

  17. 78 FR 15710 - Strong Sensitizer Guidance

    Science.gov (United States)

    2013-03-12

    ... the supplemental definition of ``strong sensitizer'' found at 16 CFR 1500.3(c)(5). The Commission is proposing to revise the supplemental definition of ``strong sensitizer'' due to advancements in the science...'' definition, assist manufacturers in understanding how CPSC staff would assess whether a substance and/or...

  18. Emission Inventory for Fugitive Emissions in Denmark

    DEFF Research Database (Denmark)

    Plejdrup, Marlene Schmidt; Nielsen, Ole-Kenneth; Nielsen, Malene

    This report presents the methodology and data used in the Danish inventory of fugitive emissions from fuels for the years until 2007. The inventory of fugitive emissions includes CO2, CH4, N2O, NOx, CO, NMVOC, SO2, dioxin, PAH and particulate matter. In 2007 the total Danish emission of greenhouse...

  19. Flaw identification using acoustic emission

    International Nuclear Information System (INIS)

    Woodward, B.; McDonald, N.R.

    1975-01-01

    In order to realise the full inspection potential of acoustic emission monitoring, data obtained from zirconium and steel testpieces have been correlated with metallurgical condition and mechanical behaviour, since the nature of emission signatures is strongly affected by the physical characteristics and internal structure of the material. During experiments, signals were tape recorded and the surface of each testpiece was recorded on movie film or videotape so that acoustic and visual information could be correlated. Large numbers of tape-recorded bursts have been analysed with a real time spectrum analyser, and statistical parameters (such as mean energy density, mean frequency and variance) derived from the spectra were calculated by an IBM 360/50 computer and selectively displayed on a line plotter. In the case of zirconium, observed differences in these parameters were an indication that the emission signals were generated by three different metallurgical mechanisms. A movie film of testpiece surface deformation revealed the occurrence of twin initiation, twin broadening and slip. Fracture events either in the zirconium matrix or in second phase particles are also possible although not observed directly. A direct correlation was confirmed between twin initiations and emission signals. Work is proceeding on establishing a different correlation between emission signals and stress corrosion cracks

  20. Biogenic emissions of isoprenoids and NO in China and comparison to anthropogenic emissions

    International Nuclear Information System (INIS)

    Tie Xuexi; Li Guohui; Ying, Zhuming; Guenther, Alex; Madronich, Sasha

    2006-01-01

    In this study, a regional dynamical model (WRF) is used to drive biogenic emission models to calculate high resolution (10 x 10 km) biogenic emissions of isoprene (C 5 H 8 ), monoterpenes (C 1 H 16 ), and nitric oxide (NO) in China. This high resolution biogenic inventory will be available for the community to study the effect of biogenic emissions on photochemical oxidants in China. The biogenic emissions are compared to anthropogenic emissions to gain insight on the potential impact of the biogenic emissions on tropospheric chemistry, especially ozone production in this region. The results show that the biogenic emissions in China exhibit strongly diurnal, seasonal, and spatial variations. The isoprenoid (including both isoprene and monoterpenes) emissions are closely correlated to tree density and strongly vary with season and local time. During winter (January), the biogenic isoprenoid emissions are the lowest, resulting from lower temperature and solar radiation, and highest in summer (July) due to higher temperature and solar radiation. The biogenic NO emissions are also higher during summer and lower during winter, but the magnitude of the seasonal variation is smaller than the emissions of isoprene and monoterpenes. The biogenic emissions of NO are widely spread out in the northern, eastern, and southern China regions, where high-density agricultural soil lands are located. Both biogenic NO and isoprenoid emissions are very small in western China. The calculated total biogenic emission budget is smaller than the total anthropogenic VOC emission budget in China. The biogenic isoprenoid and anthropogenic VOC emissions are 10.9 and 15.1 Tg year -1 , respectively. The total biogenic and anthropogenic emissions of NO are 5.9 and 11.5 Tg(NO) year -1 , respectively. The study shows that in central eastern China, the estimated biogenic emissions of isoprenoids are very small, and the anthropogenic emissions of VOCs are dominant in this region. However, in

  1. Biogenic emissions of isoprenoids and NO in China and comparison to anthropogenic emissions.

    Science.gov (United States)

    Tie, Xuexi; Li, Guohui; Ying, Zhuming; Guenther, Alex; Madronich, Sasha

    2006-12-01

    In this study, a regional dynamical model (WRF) is used to drive biogenic emission models to calculate high resolution (10x10 km) biogenic emissions of isoprene (C(5)H(8)), monoterpenes (C(10)H(16)), and nitric oxide (NO) in China. This high resolution biogenic inventory will be available for the community to study the effect of biogenic emissions on photochemical oxidants in China. The biogenic emissions are compared to anthropogenic emissions to gain insight on the potential impact of the biogenic emissions on tropospheric chemistry, especially ozone production in this region. The results show that the biogenic emissions in China exhibit strongly diurnal, seasonal, and spatial variations. The isoprenoid (including both isoprene and monoterpenes) emissions are closely correlated to tree density and strongly vary with season and local time. During winter (January), the biogenic isoprenoid emissions are the lowest, resulting from lower temperature and solar radiation, and highest in summer (July) due to higher temperature and solar radiation. The biogenic NO emissions are also higher during summer and lower during winter, but the magnitude of the seasonal variation is smaller than the emissions of isoprene and monoterpenes. The biogenic emissions of NO are widely spread out in the northern, eastern, and southern China regions, where high-density agricultural soil lands are located. Both biogenic NO and isoprenoid emissions are very small in western China. The calculated total biogenic emission budget is smaller than the total anthropogenic VOC emission budget in China. The biogenic isoprenoid and anthropogenic VOC emissions are 10.9 and 15.1 Tg year(-1), respectively. The total biogenic and anthropogenic emissions of NO are 5.9 and 11.5 Tg(NO) year(-1), respectively. The study shows that in central eastern China, the estimated biogenic emissions of isoprenoids are very small, and the anthropogenic emissions of VOCs are dominant in this region. However, in

  2. Seismic switch for strong motion measurement

    Science.gov (United States)

    Harben, P.E.; Rodgers, P.W.; Ewert, D.W.

    1995-05-30

    A seismic switching device is described that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period. 11 figs.

  3. Strong air pollution from old wood stoves

    International Nuclear Information System (INIS)

    2001-01-01

    According to this article, wood-firing is the major source of suspended dust in Norway. Old stoves emit about six times as much as new stoves. Only seven percent of the wood-firing takes place in modern, clean-burning stoves. In Oslo, where replacement of old stoves has been publicly supported, this fraction is even less. The emission of carbon dioxide from burning wood does not count as climate gas emission since the amount of CO 2 released from a burning tree equals the amount that was fixed in the growing tree, and it would have been released anyhow by the decaying tree if not burned

  4. Dual field theory of strong interactions

    International Nuclear Information System (INIS)

    Akers, D.

    1987-01-01

    A dual field theory of strong interactions is derived from a Lagrangian of the Yang-Mills and Higgs fields. The existence of a magnetic monopole of mass 2397 MeV and Dirac charge g = (137/2)e is incorporated into the theory. Unification of the strong, weak, and electromagnetic forces is shown to converge at the mass of the intermediate vector boson W/sup +/-/. The coupling constants of the strong and weak interactions are derived in terms of the fine-structure constant α = 1/137

  5. Strong and superstrong pulsed magnetic fields generation

    CERN Document Server

    Shneerson, German A; Krivosheev, Sergey I

    2014-01-01

    Strong pulsed magnetic fields are important for several fields in physics and engineering, such as power generation and accelerator facilities. Basic aspects of the generation of strong and superstrong pulsed magnetic fields technique are given, including the physics and hydrodynamics of the conductors interacting with the field as well as an account of the significant progress in generation of strong magnetic fields using the magnetic accumulation technique. Results of computer simulations as well as a survey of available field technology are completing the volume.

  6. Semi-strong split domination in graphs

    Directory of Open Access Journals (Sweden)

    Anwar Alwardi

    2014-06-01

    Full Text Available Given a graph $G = (V,E$, a dominating set $D subseteq V$ is called a semi-strong split dominating set of $G$ if $|V setminus D| geq 1$ and the maximum degree of the subgraph induced by $V setminus D$ is 1. The minimum cardinality of a semi-strong split dominating set (SSSDS of G is the semi-strong split domination number of G, denoted $gamma_{sss}(G$. In this work, we introduce the concept and prove several results regarding it.

  7. Building a strong foundation for innovation

    International Development Research Centre (IDRC) Digital Library (Canada)

    The researchers traced the heavy metal's pathway from mines to homes, and discovered that air, rather than water or food, was the main route. Emissions from mine smoke- stacks were one obvious source. The researchers also found that trucks travelling on roads paved with mining waste dispersed particles of manganese ...

  8. Sharing a quota on cumulative carbon emissions

    International Nuclear Information System (INIS)

    Raupach, Michael R.; Davis, Steven J.; Peters, Glen P.; Andrew, Robbie M.; Canadell, Josep G.; Ciais, Philippe

    2014-01-01

    Any limit on future global warming is associated with a quota on cumulative global CO 2 emissions. We translate this global carbon quota to regional and national scales, on a spectrum of sharing principles that extends from continuation of the present distribution of emissions to an equal per-capita distribution of cumulative emissions. A blend of these endpoints emerges as the most viable option. For a carbon quota consistent with a 2 C warming limit (relative to pre-industrial levels), the necessary long-term mitigation rates are very challenging (typically over 5% per year), both because of strong limits on future emissions from the global carbon quota and also the likely short-term persistence in emissions growth in many regions. (authors)

  9. Strong-force theorists scoop Noble Prize

    CERN Multimedia

    Durrani, Matin

    2004-01-01

    Three US theorists have shared the 2004 Nobel Prize in Physics "for the discovery of asymptotic freedom in the theory of the strong interaction". Their theoretical work explains why quarks behave almost as free particles at high energies (½ page)

  10. Strong-coupling theory of superconductivity

    International Nuclear Information System (INIS)

    Rainer, D.; Sauls, J.A.

    1995-01-01

    The electronic properties of correlated metals with a strong electron-phonon coupling may be understood in terms of a combination of Landau''s Fermi liquid theory and the strong-coupling theory of Migdal and Eliashberg. In these lecture notes we discuss the microscopic foundations of this phenomenological Fermi-liquid model of correlated, strong-coupling metals. We formulate the basic equations of the model, which are quasiclassical transport equations that describe both equilibrium and non-equilibrium phenomena for the normal and superconducting states of a metal. Our emphasis is on superconductors close to equilibrium, for which we derive the general linear response theory. As an application we calculate the dynamical conductivity of strong-coupling superconductors. (author)

  11. Nuclear physics from strong coupling QCD

    CERN Document Server

    Fromm, Michael

    2009-01-01

    The strong coupling limit (beta_gauge = 0) of QCD offers a number of remarkable research possibilities, of course at the price of large lattice artifacts. Here, we determine the complete phase diagram as a function of temperature T and baryon chemical potential mu_B, for one flavor of staggered fermions in the chiral limit, with emphasis on the determination of a tricritical point and on the T ~ 0 transition to nuclear matter. The latter is known to happen for mu_B substantially below the baryon mass, indicating strong nuclear interactions in QCD at infinite gauge coupling. This leads us to studying the properties of nuclear matter from first principles. We determine the nucleon-nucleon potential in the strong coupling limit, as well as masses m_A of nuclei as a function of their atomic number A. Finally, we clarify the origin of nuclear interactions at strong coupling, which turns out to be a steric effect.

  12. Modeling and synthesis of strong ground motion

    Indian Academy of Sciences (India)

    There have been many developments in modeling techniques, and ... damage life and property in a city or region. How- ... quake of 26 January 2001 as a case study. 2. ...... quake derived from a dense strong-motion network; Bull. Seismol.

  13. Physics challenges in the strong interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, S.D.

    1991-01-01

    An overview of the challenges to be faced in the area of the strong interactions during the 1990`s is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders.

  14. Physics challenges in the strong interactions

    International Nuclear Information System (INIS)

    Ellis, S.D.

    1991-01-01

    An overview of the challenges to be faced in the area of the strong interactions during the 1990's is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders

  15. Strong interaction effects in hadronic atoms

    International Nuclear Information System (INIS)

    Kaufmann, W.B.

    1977-01-01

    The WKB method is applied to the calculation of strong interaction-induced level widths and shifts of hadronic atoms. The calculation, while elementary enough for undergraduate quantum mechanics students, gives a good account of kaonic and antiprotonic atom data

  16. Perturbation of an exact strong gravity solution

    International Nuclear Information System (INIS)

    Baran, S.A.

    1982-10-01

    Perturbations of an exact strong gravity solution are investigated. It is shown, by using the new multipole expansions previously presented, that this exact and static spherically symmetric solution is stable under odd parity perturbations. (author)

  17. Calculating hadronic properties in strong QCD

    International Nuclear Information System (INIS)

    Pennington, M.R.

    1996-01-01

    This talk gives a brief review of the progress that has been made in calculating the properties of hadrons in strong QCD. In keeping with this meeting I will concentrate on those properties that can be studied with electromagnetic probes. Though perturbative QCD is highly successful, it only applies in a limited kinematic regime, where hard scattering occur, and the quarks move in the interaction region as if they are free, pointlike objects. However, the bulk of strong interactions are governed by the long distance regime, where the strong interaction is strong. It is this regime of length scales of the order of a Fermi, that determines the spectrum of light hadrons and their properties. The calculation of these properties requires an understanding of non-perturbative QCD, of confinement and chiral symmetry breaking. (author)

  18. Strong Coupling Corrections in Quantum Thermodynamics

    Science.gov (United States)

    Perarnau-Llobet, M.; Wilming, H.; Riera, A.; Gallego, R.; Eisert, J.

    2018-03-01

    Quantum systems strongly coupled to many-body systems equilibrate to the reduced state of a global thermal state, deviating from the local thermal state of the system as it occurs in the weak-coupling limit. Taking this insight as a starting point, we study the thermodynamics of systems strongly coupled to thermal baths. First, we provide strong-coupling corrections to the second law applicable to general systems in three of its different readings: As a statement of maximal extractable work, on heat dissipation, and bound to the Carnot efficiency. These corrections become relevant for small quantum systems and vanish in first order in the interaction strength. We then move to the question of power of heat engines, obtaining a bound on the power enhancement due to strong coupling. Our results are exemplified on the paradigmatic non-Markovian quantum Brownian motion.

  19. The Charm and Beauty of Strong Interactions

    Science.gov (United States)

    El-Bennich, Bruno

    2018-01-01

    We briefly review common features and overlapping issues in hadron and flavor physics focussing on continuum QCD approaches to heavy bound states, their mass spectrum and weak decay constants in different strong interaction models.

  20. Interaction of strong electromagnetic fields with atoms

    International Nuclear Information System (INIS)

    Brandi, H.S.; Davidovich, L.; Zagury, N.

    1982-06-01

    Several non-linear processes involvoing the interaction of atoms with strong laser fields are discussed, with particular emphasis on the ionization problem. Non-perturbative methods which have been proposed to tackle this problem are analysed, and shown to correspond to an expansion in the intra-atomic potential. The relation between tunneling and multiphoton absorption as ionization mechanisms, and the generalization of Einstein's photoelectric equation to the strong-field case are discussed. (Author) [pt

  1. Building strong brands – does it matter?

    OpenAIRE

    Aure, Kristin Gaaseide; Nervik, Kristine Dybvik

    2014-01-01

    Brand equity has proven, through several decades of research, to be a primary source of competitive advantage and future earnings (Yoo & Donthu, 2001). Building strong brands has therefore become a priority for many organizations, with the presumption that building strong brands yields these advantages (Yasin et al., 2007). A quantitative survey was conducted at Sunnmøre in Norway in order to answer the two developed research questions. - Does the brand equity dimensions; brand...

  2. Algebra of strong and electroweak interactions

    International Nuclear Information System (INIS)

    Bolokhov, S.V.; Vladimirov, Yu.S.

    2004-01-01

    The algebraic approach to describing the electroweak and strong interactions is considered within the frames of the binary geometrophysics, based on the principles of the Fokker-Feynman direct interparticle interaction theories of the Kaluza-Klein multidimensional geometrical models and the physical structures theory. It is shown that in this approach the electroweak and strong elementary particles interaction through the intermediate vector bosons, are characterized by the subtypes of the algebraic classification of the complex 3 x 3-matrices [ru

  3. Manipulating light with strongly modulated photonic crystals

    International Nuclear Information System (INIS)

    Notomi, Masaya

    2010-01-01

    Recently, strongly modulated photonic crystals, fabricated by the state-of-the-art semiconductor nanofabrication process, have realized various novel optical properties. This paper describes the way in which they differ from other optical media, and clarifies what they can do. In particular, three important issues are considered: light confinement, frequency dispersion and spatial dispersion. First, I describe the latest status and impact of ultra-strong light confinement in a wavelength-cubic volume achieved in photonic crystals. Second, the extreme reduction in the speed of light is reported, which was achieved as a result of frequency dispersion management. Third, strange negative refraction in photonic crystals is introduced, which results from their unique spatial dispersion, and it is clarified how this leads to perfect imaging. The last two sections are devoted to applications of these novel properties. First, I report the fact that strong light confinement and huge light-matter interaction enhancement make strongly modulated photonic crystals promising for on-chip all-optical processing, and present several examples including all-optical switches/memories and optical logics. As a second application, it is shown that the strong light confinement and slow light in strongly modulated photonic crystals enable the adiabatic tuning of light, which leads to various novel ways of controlling light, such as adiabatic frequency conversion, efficient optomechanics systems, photon memories and photons pinning.

  4. Nonlinear wave collapse and strong turbulence

    International Nuclear Information System (INIS)

    Robinson, P.A.

    1997-01-01

    The theory and applications of wave self-focusing, collapse, and strongly nonlinear wave turbulence are reviewed. In the last decade, the theory of these phenomena and experimental realizations have progressed rapidly. Various nonlinear wave systems are discussed, but the simplest case of collapse and strong turbulence of Langmuir waves in an unmagnetized plasma is primarily used in explaining the theory and illustrating the main ideas. First, an overview of the basic physics of linear waves and nonlinear wave-wave interactions is given from an introductory perspective. Wave-wave processes are then considered in more detail. Next, an introductory overview of the physics of wave collapse and strong turbulence is provided, followed by a more detailed theoretical treatment. Later sections cover numerical simulations of Langmuir collapse and strong turbulence and experimental applications to space, ionospheric, and laboratory plasmas, including laser-plasma and beam-plasma interactions. Generalizations to self-focusing, collapse, and strong turbulence of waves in other systems are also discussed, including nonlinear optics, solid-state systems, magnetized auroral and astrophysical plasmas, and deep-water waves. The review ends with a summary of the main ideas of wave collapse and strong-turbulence theory, a collection of open questions in the field, and a brief discussion of possible future research directions. copyright 1997 The American Physical Society

  5. Biogenic VOC Emissions from Tropical Landscapes

    Science.gov (United States)

    Guenther, A.; Greenberg, J.; Harley, P.; Otter, L.; Vanni Gatti, L.; Baker, B.

    2003-04-01

    Biogenic VOC have an important role in determining the chemical composition of atmosphere. As a result, these compounds are important for visibility, biogeochemical cycling, climate and radiative forcing, and the health of the biosphere. Tropical landscapes are estimated to release about 80% of total global biogenic VOC emissions but have been investigated to lesser extent than temperate regions. Tropical VOC emissions are particularly important due to the strong vertical transport and the rapid landuse change that is occurring there. This presentation will provide an overview of field measurements of biogenic VOC emissions from tropical landscapes in Amazonia (Large-scale Biosphere-atmosphere experiment in Amazonia, LBA) Central (EXPRESSO) and Southern (SAFARI 2000) Africa, Asia and Central America. Flux measurement methods include leaf-scale (enclosure measurements), canopy-scale (above canopy tower measurements), landscape-scale (tethered balloon), and regional-scale (aircraft measurements) observations. Typical midday isoprene emission rates for different landscapes vary by more than a factor of 20 with the lowest emissions observed from degraded forests. Emissions of alpha-pinene vary by a similar amount with the highest emissions associated with landscapes dominated by light dependent monoterpene emitting plants. Isoprene emissions tend to be higher for neotropical forests (Amazon and Costa Rica) in comparison to Africa and Asian tropical forests but considerable differences are observed within regions. Strong seasonal variations were observed in both the Congo and the Amazon rainforests with peak emissions during the dry seasons. Substantial emissions of light dependent monoterpenes, methanol and acetone are characteristic of at least some tropical landscapes.

  6. Continental anthropogenic primary particle number emissions

    Science.gov (United States)

    Paasonen, Pauli; Kupiainen, Kaarle; Klimont, Zbigniew; Visschedijk, Antoon; Denier van der Gon, Hugo A. C.; Amann, Markus

    2016-06-01

    Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas-Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol-cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening

  7. Continental anthropogenic primary particle number emissions

    Directory of Open Access Journals (Sweden)

    P. Paasonen

    2016-06-01

    Full Text Available Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas–Air Pollution Interactions and Synergies model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa, coke production (Russia and China, and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol–cloud interactions as well as particle number related adverse health effects, e.g. in response

  8. Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms, 1933-1994

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms is a database of over 15,000 digitized and processed accelerograph records from...

  9. Plasma emission mechanisms

    International Nuclear Information System (INIS)

    Melrose, D.B.

    1985-01-01

    Only three emission processes are thought to play a role in solar radio emission: plasma emission, gyromagnetic emission and bremsstrahlung. In this chapter plasma emission is discussed and the processes involved in its production are treated, namely, the generation of Langmuir turbulence, the partial conversion into fundamental transverse radiation, production of secondary Langmuir waves and the generation of second-harmonic transverse radiation. (U.K.)

  10. The extended reciprocity: Strong belief outperforms persistence.

    Science.gov (United States)

    Kurokawa, Shun

    2017-05-21

    The existence of cooperation is a mysterious phenomenon and demands explanation, and direct reciprocity is one key potential explanation for the evolution of cooperation. Direct reciprocity allows cooperation to evolve for cooperators who switch their behavior on the basis of information about the opponent's behavior. Here, relevant to direct reciprocity is information deficiency. When the opponent's last move is unknown, how should players behave? One possibility is to choose cooperation with some default probability without using any further information. In fact, our previous paper (Kurokawa, 2016a) examined this strategy. However, there might be beneficial information other than the opponent's last move. A subsequent study of ours (Kurokawa, 2017) examined the strategy which uses the own last move when the opponent's last move is unknown, and revealed that referring to the own move and trying to imitate it when information is absent is beneficial. Is there any other beneficial information else? How about strong belief (i.e., have infinite memory and believe that the opponent's behavior is unchanged)? Here, we examine the evolution of strategies with strong belief. Analyzing the repeated prisoner's dilemma game and using evolutionarily stable strategy (ESS) analysis against an invasion by unconditional defectors, we find the strategy with strong belief is more likely to evolve than the strategy which does not use information other than the opponent player's last move and more likely to evolve than the strategy which uses not only the opponent player's last move but also the own last move. Strong belief produces the extended reciprocity and facilitates the evolution of cooperation. Additionally, we consider the two strategies game between strategies with strong belief and any strategy, and we consider the four strategies game in which unconditional cooperators, unconditional defectors, pessimistic reciprocators with strong belief, and optimistic reciprocators with

  11. Measurement of positron range in matter in strong magnetic fields

    International Nuclear Information System (INIS)

    Hammer, B.E.; Christensen, N.L.

    1995-01-01

    Positron range is one factor that places a limitation on Positron Emission Tomography (PET) resolution. The distance a positron travels through matter before it annihilates with an electron is a function of its initial energy and the electron density of the medium. A strong magnetic field limits positron range when momentum components are transverse to the field. Measurement of positron range was determined by deconvolving the effects of detector response and radioactive distribution from the measured annihilation spread function. The annihilation spread function for a 0.5 mm bead of 68 Ga was measured with 0.2 and 1.0 mm wide slit collimators. Based on the annihilation spread function FWHM (Full Width at Half Maximum) for a 1.0 mm wide slit the median positron range in tissue equivalent material is 0.87, 0.50, 0.22 mm at 0, 5.0 and 9.4 T, respectively

  12. An integral-field spectroscopic strong lens survey

    International Nuclear Information System (INIS)

    Bolton, Adam S; Burles, Scott

    2007-01-01

    We present the observational results of a survey for strong gravitational lens systems consisting of extended emission-line galaxies lensed by intervening early-type galaxies, conducted using integral field units (IFUs) of the Magellan IMACS and Gemini GMOS-N spectrographs. These data are highly valuable for corroborating the lensing interpretation of Hubble Space Telescope imaging data. We show that in many cases, ground-based IFU spectroscopy is in fact competitive with space-based imaging for the measurement of the mass model parameters of the lensing galaxy. We demonstrate a novel technique of three-dimensional gravitational lens modeling for a single lens system with a resolved lensed rotation curve. We also describe the details of our custom IFU data analysis software, which performs optimal multi-fiber extraction, relative and absolute wavelength calibration to a few hundredths of a pixel RMS and nearly Poisson-limited sky subtraction

  13. Evaluating Bay Area Methane Emission Inventory

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Marc [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jeong, Seongeun [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-03-01

    . In total, we estimate the anthropogenic emissions for BAAQMD to be 116.4 Gg (1 Gg = 109 g) CH4/yr, with a likely uncertainty of ~ 50% or more (e.g., NRC, 2010; US-EPA, 2015). Including the emissions from wetland (Jeong et al., 2013), the total CH4 emission estimate for BAAQMD is 120.1 Gg CH4/yr. Table 1 summarizes the estimated CH4 emissions for 2011 by sector. The sectors were categorized following those that are used in recent regional emission quantification studies (e.g., Jeong et al., 2013; Peischl et al., 2013; Wecht et al., 2014). However, we note that this result is marginally lower than the top-down estimate of 240 ± 60 Gg CH4/yr (at 95% confidence) reported by Fairley and Fischer (2015), suggesting some combination of systematic error in the top-down estimate, underestimation of emissions from known sources, or as yet unidentified sources may be present. With respect to the relative contributions from different source sectors, the CH4 emissions from the region are dominated by urban activities. Landfill emissions represent 53% of the District’s total emission followed by livestock (16%) and natural gas (15%). These three dominant sectors account for 84% of the total anthropogenic emission in BAAQMD. This suggests that mitigation efforts need to focus on these three sources. Figure 1 shows the gridded anthropogenic CH4 emissions on the BAAQMD’s 1-km grid. In general, the spatial pattern of emissions follows the density of population while strong point sources are also distributed in the rural areas of the District. Detailed methods and emissions for each sector and county are described in the following sections.

  14. Particularities of surface plasmon-exciton strong coupling with large Rabi splitting

    International Nuclear Information System (INIS)

    Symonds, C; Bonnand, C; Plenet, J C; Brehier, A; Parashkov, R; Lauret, J S; Deleporte, E; Bellessa, J

    2008-01-01

    This paper presents some of the particularities of the strong coupling regime occurring between surface plasmon (SP) modes and excitons. Two different active materials were deposited on a silver film: a cyanine dye J-aggregate, and a two-dimensional layered perovskite-type semiconductor. The dispersion relations, which are deduced from angular resolved reflectometry spectra, present an anticrossing characteristic of the strong coupling regime. The wavevector is a good parameter to determine the Rabi splitting. Due to the large interaction energies (several hundreds of milli-electron-volts), the calculations at constant angle can induce an overestimation of the Rabi splitting of more than a factor of two. Another property of polaritons based on SP is their nonradiative character. In order to observe the polaritonic emission, it is thus necessary to use particular extraction setups, such as gratings or prisms. Otherwise only the incoherent emission can be detected, very similar to the bare exciton emission

  15. TOWARD AN EMPIRICAL THEORY OF PULSAR EMISSION. X. ON THE PRECURSOR AND POSTCURSOR EMISSION

    International Nuclear Information System (INIS)

    Basu, Rahul; Mitra, Dipanjan; Rankin, Joanna M.

    2015-01-01

    Precursors and postcursors (PPCs) are rare emission components, which appear beyond the main pulse emission, in some cases far away from it, and are detected in a handful of pulsar. In this paper we attempt to characterize the PPC emission in relation to the pulsar main pulse geometry. In our analysis we find that PPC components have properties very different from that of outer conal emission. The separation of the PPC components from the main pulse center remains constant with frequency. In addition the beam opening angles corresponding to the separation of PPC components from the pulsar center are much larger than the largest encountered in conal emission. Pulsar radio emission is believed to originate within the magnetic polar flux tubes due to the growth of instabilities in the outflowing relativistic plasma. Observationally, there is strong evidence that the main pulse emission originates at altitudes of about 50 neutron star radii for a canonical pulsar. Currently, the most plausible radio emission model that can explain main pulse emission is the coherent curvature radiation mechanism, wherein relativistic charged solitons are formed in a non-stationary electron-positron-pair plasma. The wider beam opening angles of PPC require the emission to emanate from larger altitudes as compared to the main pulse, if both these components originate by the same emission mechanism. We explore this possibility and find that this emission mechanism is probably inapplicable at the height of the PPC emission. We propose that the PPC emission represents a new type of radiation from pulsars with a mechanism different from that of the main pulse

  16. Electromagnetic processes in strong crystalline fields

    CERN Document Server

    Uggerhoj, U I; Esberg, J; Knudsen, H; Lund, M; Møller, S P; Sørensen, A H; Thomsen, A H; Uggerhøj, U I; Geissel, H; Scheidenberger, C; Weick, H; Winfield, J; Sona, P; Connell S; Ballestrero, S; Ketel, T; Dizdar, A; Mangiarotti, A

    2009-01-01

    As an addendum to the NA63 proposal cite{Ande05}, we propose to measure 1) the Landau-Pomeranchuk-Migdal (LPM) effect in low-$Z$ targets, 2) Magnetic suppression of incoherent bremsstrahlung resulting from exposure to an external field during the emission event, and 3) the bremsstrahlung emission from relativistic ($gamma=170$), fully stripped Pb nuclei penetrating various amorphous targets. Concerning the LPM effect, both the 'traditional' Migdal approach and the modern treatment by Baier and Katkov display inaccuracies, i.e. a possible lack of applicability in low-$Z$ targets. Moreover, the LPM effect has been shown to have a significant impact on giant air showers for energies in the EeV range - evidently processes in a low-$Z$ material. A measurement of magnetic suppression is demanding in terms of necessary accuracy (an expected $lesssim$15% effect), but would prove the existence of a basic interplay between coherent and incoherent processes, also believed to be significant in beamstrahlung emission. For...

  17. CO2 emissions: a peak level in 2010

    International Nuclear Information System (INIS)

    Anon.

    2011-01-01

    After a reduction of CO 2 emissions in 2009 due to the financial crisis, these emissions have again reached a peak in 2010: 30.6 Gt, it means an increase by 5% compared to the previous peak. According to IEA (International Energy Agency): 44% of the emissions come from coal, 36% from oil and 20% from natural gas, and OECD countries are responsible of 40% of the CO 2 global emissions but only of 25% of their increase since 2009. For China and India the emissions of CO 2 have increased sharply due to their strong economic growth. (A.C.)

  18. Cooperative emission in ion implanted Yb:YAG waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, G V; Desirena, H; De la Rosa, E [Centro de Investigaciones en Optica, Loma del Bosque 115, Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Flores-Romero, E; Rickards, J; Trejo-Luna, R [Instituto de Fisica, UNAM, Apartado Postal 20364, 01000 Mexico, D. F. (Mexico); Marquez, H, E-mail: gvvazquez@cio.mx [Departamento de Optica, CICESE, Km 107 Carr. Tijuana-Ensenada, 22860 Ensenada, B. C. (Mexico)

    2011-01-01

    In this work, we report the analysis of spectroscopic properties of waveguides fabricated by ion implantation in YAG doped with Yb{sup 3+} ions. Three emission bands were detected in the blue, green and red regions under 970-nm excitation. The strong blue-green emission can be explained by a cooperative process between ytterbium ion pairs, leading to emission centered at 514 nm. The additional blue bands as well as green and red emission bands are attributed to the presence of Tm{sup 3+} and Er{sup 3+} traces. The results include absorption and emission curves as well as decay time rates.

  19. Cooperative emission in ion implanted Yb:YAG waveguides

    International Nuclear Information System (INIS)

    Vazquez, G V; Desirena, H; De la Rosa, E; Flores-Romero, E; Rickards, J; Trejo-Luna, R; Marquez, H

    2011-01-01

    In this work, we report the analysis of spectroscopic properties of waveguides fabricated by ion implantation in YAG doped with Yb 3+ ions. Three emission bands were detected in the blue, green and red regions under 970-nm excitation. The strong blue-green emission can be explained by a cooperative process between ytterbium ion pairs, leading to emission centered at 514 nm. The additional blue bands as well as green and red emission bands are attributed to the presence of Tm 3+ and Er 3+ traces. The results include absorption and emission curves as well as decay time rates.

  20. Strong Photoluminescence Enhancement of Silicon Oxycarbide through Defect Engineering

    Directory of Open Access Journals (Sweden)

    Brian Ford

    2017-04-01

    Full Text Available The following study focuses on the photoluminescence (PL enhancement of chemically synthesized silicon oxycarbide (SiCxOy thin films and nanowires through defect engineering via post-deposition passivation treatments. SiCxOy materials were deposited via thermal chemical vapor deposition (TCVD, and exhibit strong white light emission at room-temperature. Post-deposition passivation treatments were carried out using oxygen, nitrogen, and forming gas (FG, 5% H2, 95% N2 ambients, modifying the observed white light emission. The observed white luminescence was found to be inversely related to the carbonyl (C=O bond density present in the films. The peak-to-peak PL was enhanced ~18 and ~17 times for, respectively, the two SiCxOy matrices, oxygen-rich and carbon-rich SiCxOy, via post-deposition passivations. Through a combinational and systematic Fourier transform infrared spectroscopy (FTIR and PL study, it was revealed that proper tailoring of the passivations reduces the carbonyl bond density by a factor of ~2.2, corresponding to a PL enhancement of ~50 times. Furthermore, the temperature-dependent and temperature-dependent time resolved PL (TDPL and TD-TRPL behaviors of the nitrogen and forming gas passivated SiCxOy thin films were investigated to acquire further insight into the ramifications of the passivation on the carbonyl/dangling bond density and PL yield.

  1. Diffusion and Evaporation-Controlled Emission in Ventilated Rooms

    DEFF Research Database (Denmark)

    Topp, Claus

    and sources. This work provides an investigation based on fundamental fluid dynamics and mass transfer theory to obtain a general understanding of the mechanisms involved in the emission from building materials in ventilated rooms. In addition, a generally applicable model for prediction of surface emission...... is proposed. The interest has been focused on the emission of vapours and gases as no particulate emissions have been considered. The methods used are numerical calculations by computational fluid dynamics (CFD) and full-scale laboratory experiments. It was found that the emission is a strong function of air......In emission studies reported in literature little effort has been made to investigate the emission from building materials in ventilated enclosures from a fluid dynamics point of view. Furthermore, most of the existing emission models are empirical relations that are based on specific pollutants...

  2. Coherent Vortices in Strongly Coupled Liquids

    International Nuclear Information System (INIS)

    Ashwin, J.; Ganesh, R.

    2011-01-01

    Strongly coupled liquids are ubiquitous in both nature and laboratory plasma experiments. They are unique in the sense that their average potential energy per particle dominates over the average kinetic energy. Using ''first principles'' molecular dynamics (MD) simulations, we report for the first time the emergence of isolated coherent tripolar vortices from the evolution of axisymmetric flows in a prototype two-dimensional (2D) strongly coupled liquid, namely, the Yukawa liquid. Linear growth rates directly obtained from MD simulations are compared with a generalized hydrodynamic model. Our MD simulations reveal that the tripolar vortices persist over several turn over times and hence may be observed in strongly coupled liquids such as complex plasma, liquid metals and astrophysical systems such as white dwarfs and giant planetary interiors, thereby making the phenomenon universal.

  3. Coherent Vortices in Strongly Coupled Liquids

    Science.gov (United States)

    Ashwin, J.; Ganesh, R.

    2011-04-01

    Strongly coupled liquids are ubiquitous in both nature and laboratory plasma experiments. They are unique in the sense that their average potential energy per particle dominates over the average kinetic energy. Using “first principles” molecular dynamics (MD) simulations, we report for the first time the emergence of isolated coherent tripolar vortices from the evolution of axisymmetric flows in a prototype two-dimensional (2D) strongly coupled liquid, namely, the Yukawa liquid. Linear growth rates directly obtained from MD simulations are compared with a generalized hydrodynamic model. Our MD simulations reveal that the tripolar vortices persist over several turn over times and hence may be observed in strongly coupled liquids such as complex plasma, liquid metals and astrophysical systems such as white dwarfs and giant planetary interiors, thereby making the phenomenon universal.

  4. Institutionalizing Strong Sustainability: A Rawlsian Perspective

    Directory of Open Access Journals (Sweden)

    Konrad Ott

    2014-02-01

    Full Text Available The article aims to provide some ethical orientation on how sustainability might be actualized by institutions. Since institutionalization is about rules and organization, it presupposes ideas and concepts by which institutions can be substantiated. After outlining terminology, the article deals with underlying ethical and conceptual problems which are highly relevant for any suggestions concerning institutionalization. These problems are: (a the ethical scope of the sustainability perspective (natural capital, poverty, sentient animals, (b the theory of justice on which ideas about sustainability are built (capability approach, Rawlsianism, and (c the favored concept of sustainability (weak, intermediate, and strong sustainability. These problems are analyzed in turn. As a result, a Rawlsian concept of rule-based strong sustainability is proposed. The specific problems of institutionalization are addressed by applying Rawls’s concept of branches. The article concludes with arguments in favor of three transnational duties which hold for states that have adopted Rawlsian strong sustainability.

  5. A theory of the strong interactions

    International Nuclear Information System (INIS)

    Gross, D.J.

    1979-01-01

    The most promising candidate for a fundamental microscopic theory of the strong interactions is a gauge theory of colored quarks-Quantum Chromodynamics (QCD). There are many excellent reasons for believing in this theory. It embodies the broken symmetries, SU(3) and chiral SU(3)xSU(3), of the strong interactions and reflects the success of (albeit crude) quark models in explaining the spectrum of the observed hadrons. The hidden quantum number of color, necessary to account for the quantum numbers of the low lying hadrons, plays a fundamental role in this theory as the SU(3) color gauge vector 'gluons' are the mediators of the strong interactions. The absence of physical quark states can be 'explained' by the hypothesis of color confinement i.e. that hadrons are permanently bound in color singlet bound states. Finally this theory is unique in being asymptotically free, thus accounting for the almost free field theory behvior of quarks observed at short distances. (Auth.)

  6. Electronic Structure of Strongly Correlated Materials

    CERN Document Server

    Anisimov, Vladimir

    2010-01-01

    Electronic structure and physical properties of strongly correlated materials containing elements with partially filled 3d, 4d, 4f and 5f electronic shells is analyzed by Dynamical Mean-Field Theory (DMFT). DMFT is the most universal and effective tool used for the theoretical investigation of electronic states with strong correlation effects. In the present book the basics of the method are given and its application to various material classes is shown. The book is aimed at a broad readership: theoretical physicists and experimentalists studying strongly correlated systems. It also serves as a handbook for students and all those who want to be acquainted with fast developing filed of condensed matter physics.

  7. Strongly interacting matter in magnetic fields

    CERN Document Server

    Landsteiner, Karl; Schmitt, Andreas; Yee, Ho-Ung

    2013-01-01

    The physics of strongly interacting matter in an external magnetic field is presently emerging as a topic of great cross-disciplinary interest for particle, nuclear, astro- and condensed matter physicists. It is known that strong magnetic fields are created in heavy ion collisions, an insight that has made it possible to study a variety of surprising and intriguing phenomena that emerge from the interplay of quantum anomalies, the topology of non-Abelian gauge fields, and the magnetic field. In particular, the non-trivial topological configurations of the gluon field induce a non-dissipative electric current in the presence of a magnetic field. These phenomena have led to an extended formulation of relativistic hydrodynamics, called chiral magnetohydrodynamics. Hitherto unexpected applications in condensed matter physics include graphene and topological insulators. Other fields of application include astrophysics, where strong magnetic fields exist in magnetars and pulsars. Last but not least, an important ne...

  8. Aperture averaging in strong oceanic turbulence

    Science.gov (United States)

    Gökçe, Muhsin Caner; Baykal, Yahya

    2018-04-01

    Receiver aperture averaging technique is employed in underwater wireless optical communication (UWOC) systems to mitigate the effects of oceanic turbulence, thus to improve the system performance. The irradiance flux variance is a measure of the intensity fluctuations on a lens of the receiver aperture. Using the modified Rytov theory which uses the small-scale and large-scale spatial filters, and our previously presented expression that shows the atmospheric structure constant in terms of oceanic turbulence parameters, we evaluate the irradiance flux variance and the aperture averaging factor of a spherical wave in strong oceanic turbulence. Irradiance flux variance variations are examined versus the oceanic turbulence parameters and the receiver aperture diameter are examined in strong oceanic turbulence. Also, the effect of the receiver aperture diameter on the aperture averaging factor is presented in strong oceanic turbulence.

  9. Frictional Coulomb drag in strong magnetic fields

    DEFF Research Database (Denmark)

    Bønsager, Martin Christian; Flensberg, Karsten; Hu, Ben Yu-Kuang

    1997-01-01

    A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21) is eval......A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21...

  10. Analytical solution of strongly nonlinear Duffing oscillators

    OpenAIRE

    El-Naggar, A.M.; Ismail, G.M.

    2016-01-01

    In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε)α=α(ε) is defined such that the value of α is always small regardless of the magnitude of the original parameter εε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to αα. Approximate solution obtained by the present method is compared with the solution of energy balance m...

  11. Strong WW scattering at photon linear colliders

    International Nuclear Information System (INIS)

    Berger, M.S.

    1994-06-01

    We investigate the possibility of observing strong interactions of longitudinally polarized weak vector bosons in the process γγ → ZZ at a photon linear collider. We make use of polarization of the photon beams and cuts on the decay products of the Z bosons to enhance the signal relative to the background of transversely polarized ZZ pairs. We find that the background overwhelms the signal unless there are strong resonant effects, as for instance from a technicolor analogue of the hadronic f 2 (1270) meson

  12. Nonlinear Electron Waves in Strongly Magnetized Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans; Juul Rasmussen, Jens

    1980-01-01

    Weakly nonlinear dispersive electron waves in strongly magnetized plasma are considered. A modified nonlinear Schrodinger equation is derived taking into account the effect of particles resonating with the group velocity of the waves (nonlinear Landau damping). The possibility of including the ion...... dynamics in the analysis is also demonstrated. As a particular case the authors investigate nonlinear waves in a strongly magnetized plasma filled wave-guide, where the effects of finite geometry are important. The relevance of this problem to laboratory experiments is discussed....

  13. Universal behavior of strongly correlated Fermi systems

    Energy Technology Data Exchange (ETDEWEB)

    Shaginyan, Vasilii R [B.P. Konstantinov St. Petersburg Institute of Nuclear Physics, Russian Academy of Sciences, Gatchina, Leningrad region, Rusian Federation (Russian Federation); Amusia, M Ya [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation); Popov, Konstantin G [Komi Scientific Center, Ural Branch of the Russian Academy of Sciences, Syktyvkar (Russian Federation)

    2007-06-30

    This review discusses the construction of a theory and the analysis of phenomena occurring in strongly correlated Fermi systems such as high-T{sub c} superconductors, heavy-fermion metals, and quasi-two-dimensional Fermi systems. It is shown that the basic properties and the universal behavior of strongly correlated Fermi systems can be described in the framework of the Fermi-condensate quantum phase transition and the well-known Landau paradigm of quasiparticles and the order parameter. The concept of fermion condensation may be fruitful in studying neutron stars, finite Fermi systems, ultra-cold gases in traps, and quark plasma. (reviews of topical problems)

  14. Universal behavior of strongly correlated Fermi systems

    International Nuclear Information System (INIS)

    Shaginyan, Vasilii R; Amusia, M Ya; Popov, Konstantin G

    2007-01-01

    This review discusses the construction of a theory and the analysis of phenomena occurring in strongly correlated Fermi systems such as high-T c superconductors, heavy-fermion metals, and quasi-two-dimensional Fermi systems. It is shown that the basic properties and the universal behavior of strongly correlated Fermi systems can be described in the framework of the Fermi-condensate quantum phase transition and the well-known Landau paradigm of quasiparticles and the order parameter. The concept of fermion condensation may be fruitful in studying neutron stars, finite Fermi systems, ultra-cold gases in traps, and quark plasma. (reviews of topical problems)

  15. De Sitter vacua of strongly interacting QFT

    Energy Technology Data Exchange (ETDEWEB)

    Buchel, Alex [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Department of Physics and Astronomy, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Perimeter Institute for Theoretical Physics,Waterloo, Ontario N2J 2W9 (Canada); Karapetyan, Aleksandr [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada)

    2017-03-22

    We use holographic correspondence to argue that Euclidean (Bunch-Davies) vacuum is a late-time attractor of the dynamical evolution of quantum gauge theories at strong coupling. The Bunch-Davies vacuum is not an adiabatic state, if the gauge theory is non-conformal — the comoving entropy production rate is nonzero. Using the N=2{sup ∗} gauge theory holography, we explore prospects of explaining current accelerated expansion of the Universe as due to the vacuum energy of a strongly coupled QFT.

  16. Optical spectral weight anomalies and strong correlation

    International Nuclear Information System (INIS)

    Toschi, A.; Capone, M.; Ortolani, M.; Calvani, P.; Lupi, S.; Castellani, C.

    2007-01-01

    The anomalous behavior observed in the optical spectral weight (W) of the cuprates provides valuable information about the physics of these compounds. Both the doping and the temperature dependences of W are hardly explained through conventional estimates based on the f-sum rule. By computing the optical conductivity of the doped Hubbard model with the Dynamical Mean Field Theory, we point out that the strong correlation plays a key role in determining the basic features of the observed anomalies: the proximity to a Mott insulating phase accounts simultaneously for the strong temperature dependence of W and for its zero temperature value

  17. Strong cosmic censorship in de Sitter space

    Science.gov (United States)

    Dias, Oscar J. C.; Eperon, Felicity C.; Reall, Harvey S.; Santos, Jorge E.

    2018-05-01

    Recent work indicates that the strong cosmic censorship hypothesis is violated by nearly extremal Reissner-Nordström-de Sitter black holes. It was argued that perturbations of such a black hole decay sufficiently rapidly that the perturbed spacetime can be extended across the Cauchy horizon as a weak solution of the equations of motion. In this paper we consider the case of Kerr-de Sitter black holes. We find that, for any nonextremal value of the black hole parameters, there are quasinormal modes which decay sufficiently slowly to ensure that strong cosmic censorship is respected. Our analysis covers both scalar field and linearized gravitational perturbations.

  18. The value relevance of environmental emissions

    Directory of Open Access Journals (Sweden)

    Melinda Lydia Nelwan

    2016-07-01

    Full Text Available This study examines whether environmental performance has value relevance by investigating the relations between environmental emissions and stock prices for the U.S. public companies. The previous studies argued that the conjectured relations between accounting performance measures and environmental performance do not have a strong theoretical basis, and the modeling of relations between market per-formance measures and environmental performance do not adequately consider the relevance of accounting performance to market value. Therefore, this study examines whether publicly reported environmental emissions provide incremental information to accounting earnings in pricing companies stocks. It is done among the complete set of industries covered by Toxics Release Inventory (TRI reporting for the period 2007 to 2010. Using Ohlson model but modified to include different types of emis-sions, it is found that ground emissions (underground injection and land emissions are value relevant but other emission types (air and water and transferred-out emis-sions appear to not provide incremental information in the valuation model. The result in this study raise concerns that different types of emissions are assessed differently by the market, confirming that studies should not aggregate such measures.

  19. Radio Emissions from Magnetopause Reconnection Events

    Science.gov (United States)

    Fung, S. F.; Kunze, J.

    2017-12-01

    A new terrestrial radio emission has recently been identified and attributed to a source connected to the magnetopause magnetic reconnection process [Fung et al., 2013]. Known as the terrestrial myriametric radio burst (TMRB), the new emission was observed by both the IMAGE and Geotail spacecraft during a period of northward interplanetary magnetic field (IMF Bz >0) as a temporal and isolated burst of emission with perhaps well-defined or directed emission cones. Spectral and spin-modulation analyses showed that both the intensity and source direction of the emission are sensitive to the variability of the IMF. The strong control of the emission by the IMF suggests that the emission is connected to the magnetopause reconnection process. A number of potential TMRB events have now been identified by surveying all the dynamic spectrogram data obtained by the IMAGE, Geotail, Cluster, and Wind spacecraft in 5/2000-12/2005. This paper will present our analyses of how the spectral signatures and beaming characteristics of the emissions might depend on the IMF orientations, and thus their likelihood of being TMRBs. Special emphasis will be on events associated with northward and southward IMF in order to determine if TMRBs might be generally produced from magnetopause reconnection processes. Fung, S. F., K. Hashimoto, H. Kojima, S. A. Boardsen, L. N. Garcia, H. Matsumoto, J. L. Green, and B. W. Reinisch (2013), Terrestrial myriametric radio burst observed by IMAGE and Geotail satellites, J. Geophys. Res. Space Physics, 118, doi:10.1002/jgra.50149.

  20. Vehicle Emissions Risk Management

    International Nuclear Information System (INIS)

    Ibrahem, L.G.

    2004-01-01

    Vehicle emissions are considered as a main source for air pollution. Emissions regulation is now well developed in most countries to meet cleaner air quality. Reducing emissions by using cleaner fuels, which meet certain specification, is not enough to get cleaner air, yet the vehicle technology is not improved. Here we will outline the following: - development in fuel specification and emissions regulation. main facts linking vehicle emissions, fuel properties and air quality. catalytic converter technology. Emissions sources: In modem cities, vehicle traffic is potentially a major source of emissions. However sometimes other sources of emissions from industry and other stationary sources can be equally important and include emissions that are of greater toxicity than those from vehicles

  1. Understanding strong-field coherent control: Measuring single-atom versus collective dynamics

    International Nuclear Information System (INIS)

    Trallero-Herrero, Carlos; Weinacht, Thomas; Spanner, Michael

    2006-01-01

    We compare the results of two strong field coherent control experiments: one which optimizes multi-photon population transfer in atomic sodium (from the 3s to the 4s state, measured by spontaneous emission from the 3p-3s transition) with one that optimizes stimulated emission on the 3p-3s transition in an ensemble of sodium atoms. Both experiments make use of intense, shaped ultrafast laser pulses discovered by a Genetic Algorithm inside a learning control loop. Optimization leads to improvements in the spontaneous and stimulated emission yields of about 4 and 10 4 , respectively, over an unshaped pulse. We interpret these results by modeling both the single atom dynamics as well as the stimulated emission buildup through numerical integration of Schroedinger's and Maxwell's equations. Our interpretation leads to the conclusion that modest yields for controlling single quantum systems can lead to dramatic effects whenever an ensemble of such systems acts collectively following controlled impulsive excitation

  2. Aerosol emission during human speech

    Science.gov (United States)

    Asadi, Sima; Wexler, Anthony S.; Cappa, Christopher D.; Bouvier, Nicole M.; Barreda-Castanon, Santiago; Ristenpart, William D.

    2017-11-01

    We show that the rate of aerosol particle emission during healthy human speech is strongly correlated with the loudness (amplitude) of vocalization. Emission rates range from approximately 1 to 50 particles per second for quiet to loud amplitudes, regardless of language spoken (English, Spanish, Mandarin, or Arabic). Intriguingly, a small fraction of individuals behave as ``super emitters,'' consistently emitting an order of magnitude more aerosol particles than their peers. We interpret the results in terms of the eggressive flowrate during vocalization, which is known to vary significantly for different types of vocalization and for different individuals. The results suggest that individual speech patterns could affect the probability of airborne disease transmission. The results also provide a possible explanation for the existence of ``super spreaders'' who transmit pathogens much more readily than average and who play a key role in the spread of epidemics.

  3. Asymmetry of neutrino emission from neutron beta-decay in superdense matter and strong magnetic field

    International Nuclear Information System (INIS)

    Kauts, V.L.; Savochkin, A.M.; Studenikin, A.I.

    2006-01-01

    Exact solution of Dirac equation for charged particles in homogenous magnetic field for computation of probability in presence of degenerate magnetized Fermi-gas consisting of protons, neutrons, and electrons has been used. Angular distribution of antineutrino momenta is investigated. Values of main parameters of medium is realistic for physics of neutron stars. This investigation may be applied for consideration of cooling of neutron stars [ru

  4. The detectability of radio emission from exoplanets

    Science.gov (United States)

    Lynch, C. R.; Murphy, Tara; Lenc, E.; Kaplan, D. L.

    2018-05-01

    Like the magnetised planets in our Solar System, magnetised exoplanets should emit strongly at radio wavelengths. Radio emission directly traces the planetary magnetic fields and radio detections can place constraints on the physical parameters of these features. Large comparative studies of predicted radio emission characteristics for the known population of exoplanets help to identify what physical parameters could be key for producing bright, observable radio emission. Since the last comparative study, many thousands of exoplanets have been discovered. We report new estimates for the radio flux densities and maximum emission frequencies for the current population of known exoplanets orbiting pre-main sequence and main-sequence stars with spectral types F-M. The set of exoplanets predicted to produce observable radio emission are Hot Jupiters orbiting young stars. The youth of these system predicts strong stellar magnetic fields and/or dense winds, which are key for producing bright, observable radio emission. We use a new all-sky circular polarisation Murchison Widefield Array survey to place sensitive limits on 200 MHz emission from exoplanets, with 3σ values ranging from 4.0 - 45.0 mJy. Using a targeted Giant Metre Wave Radio Telescope observing campaign, we also report a 3σ upper limit of 4.5 mJy on the radio emission from V830 Tau b, the first Hot Jupiter to be discovered orbiting a pre-main sequence star. Our limit is the first to be reported for the low-frequency radio emission from this source.

  5. Strong coupling of two interacting excitons confined in a nanocavity-quantum dot system

    International Nuclear Information System (INIS)

    Cardenas, Paulo C; RodrIguez, Boris A; Quesada, Nicolas; Vinck-Posada, Herbert

    2011-01-01

    We present a study of the strong coupling between radiation and matter, considering a system of two quantum dots, which are in mutual interaction and interact with a single mode of light confined in a semiconductor nanocavity. We take into account dissipative mechanisms such as the escape of the cavity photons, decay of the quantum dot excitons by spontaneous emission, and independent exciton pumping. It is shown that the mutual interaction between the dots can be measured off-resonance only if the strong coupling condition is reached. Using the quantum regression theorem, a reasonable definition of the dynamical coupling regimes is introduced in terms of the complex Rabi frequency. Finally, the emission spectrum for relevant conditions is presented and compared with the above definition, demonstrating that the interaction between the excitons does not affect the strong coupling.

  6. Ammonia emissions in Europe

    DEFF Research Database (Denmark)

    Jacobsen, Brian H.

    2012-01-01

    The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the la......The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries...

  7. Natural strong CP conservation in flipped physics

    Energy Technology Data Exchange (ETDEWEB)

    Frampton, P.H. (Institute of Field Physics, Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC (USA)); Kephart, T.W. (Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (USA))

    1990-08-13

    A natural axion-free solution of the strong {ital CP} problem {ital at} {ital tree} {ital level} is noted within an E(6) grand unified theory. Using this as a springboard, it is shown that several flipped SU(5) theories which occur in superstring phenomenology contain within them a mechanism which enforces {bar {theta}}=0 at high accuracy.

  8. Riesz basis for strongly continuous groups.

    NARCIS (Netherlands)

    Zwart, Heiko J.

    Given a Hilbert space and the generator of a strongly continuous group on this Hilbert space. If the eigenvalues of the generator have a uniform gap, and if the span of the corresponding eigenvectors is dense, then these eigenvectors form a Riesz basis (or unconditional basis) of the Hilbert space.

  9. Earthquake source model using strong motion displacement

    Indian Academy of Sciences (India)

    The strong motion displacement records available during an earthquake can be treated as the response of the earth as the a structural system to unknown forces acting at unknown locations. Thus, if the part of the earth participating in ground motion is modelled as a known finite elastic medium, one can attempt to model the ...

  10. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown...

  11. Discrete symmetries, strong CP problem and gravity

    International Nuclear Information System (INIS)

    Senjanovic, G.

    1993-05-01

    Spontaneous breaking of parity or time reversal invariance offers a solution to the strong CP problem, the stability of which under quantum gravitational effects provides an upper limit on the scale of symmetry breaking. Even more important, these Planck scale effects may provide a simple and natural way out of the resulting domain wall problem. (author). 22 refs

  12. Phase transition from strong-coupling expansion

    International Nuclear Information System (INIS)

    Polonyi, J.; Szlachanyi, K.

    1982-01-01

    Starting with quarkless SU(2) lattice gauge theory and using the strong-coupling expansion we calculate the action of the effective field theory which corresponds to the thermal Wilson loop. This effective action makes evident that the quark liberating phase transition traces back to the spontaneous breaking of a global Z(2) symmetry group. It furthermore describes both phases qualitatively. (orig.)

  13. The stability of the strong gravity solution

    International Nuclear Information System (INIS)

    Baran, S.A.

    1978-01-01

    The perturbation of the classical solution to a strong gravity model given by Salam and Strathdee is investigated. Using the Hamiltonian formalism it is shown that this static and spherically symmetric solution is stable under the odd parity perturbations provided some parameters in the solution are suitably restricted

  14. Chaos desynchronization in strongly coupled systems

    International Nuclear Information System (INIS)

    Wu Ye; Liu Weiqing; Xiao, Jinghua; Zhan Meng

    2007-01-01

    The dynamics of chaos desynchronization in strongly coupled oscillator systems is studied. We find a new bifurcation from synchronous chaotic state, chaotic short wave bifurcation, i.e. a chaotic desynchronization attractor is new born in the systems due to chaos desynchronization. In comparison with the usual periodic short wave bifurcation, very rich but distinct phenomena are observed

  15. Strong motion duration and earthquake magnitude relationships

    International Nuclear Information System (INIS)

    Salmon, M.W.; Short, S.A.; Kennedy, R.P.

    1992-06-01

    Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ''strong motion duration'' has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions

  16. Strong imploding shock, the representative curve

    International Nuclear Information System (INIS)

    Mishkin, E.A.; Alejaldre, C.

    1981-01-01

    The representative curve of the ideal gas behind the front of a spherically, or cylindrically, symmetric strong imploding shock is shown to pass through the point where the reduced pressure is maximum, P(xisub(m)) = Psub(m)sub(a)sub(x). (orig.)

  17. Reducing Weak to Strong Bisimilarity in CCP

    Directory of Open Access Journals (Sweden)

    Andrés Aristizábal

    2012-12-01

    Full Text Available Concurrent constraint programming (ccp is a well-established model for concurrency that singles out the fundamental aspects of asynchronous systems whose agents (or processes evolve by posting and querying (partial information in a global medium. Bisimilarity is a standard behavioural equivalence in concurrency theory. However, only recently a well-behaved notion of bisimilarity for ccp, and a ccp partition refinement algorithm for deciding the strong version of this equivalence have been proposed. Weak bisimiliarity is a central behavioural equivalence in process calculi and it is obtained from the strong case by taking into account only the actions that are observable in the system. Typically, the standard partition refinement can also be used for deciding weak bisimilarity simply by using Milner's reduction from weak to strong bisimilarity; a technique referred to as saturation. In this paper we demonstrate that, because of its involved labeled transitions, the above-mentioned saturation technique does not work for ccp. We give an alternative reduction from weak ccp bisimilarity to the strong one that allows us to use the ccp partition refinement algorithm for deciding this equivalence.

  18. Physics challenges in the strong interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, S.D.

    1991-01-01

    An overview of the challenges to be faced in the area of the strong interactions during the 1990's is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders.

  19. Strongly \\'etale difference algebras and Babbitt's decomposition

    OpenAIRE

    Tomašić, Ivan; Wibmer, Michael

    2015-01-01

    We introduce a class of strongly \\'{e}tale difference algebras, whose role in the study of difference equations is analogous to the role of \\'{e}tale algebras in the study of algebraic equations. We deduce an improved version of Babbitt's decomposition theorem and we present applications to difference algebraic groups and the compatibility problem.

  20. Strong-coupling diffusion in relativistic systems

    Indian Academy of Sciences (India)

    hanced values needed to interpret the data at higher energies point towards the importance of strong-coupling effects. ... when all secondary particles have been created. For short times in the initial phase ... It is decisive for a proper representation of the available data for relativistic heavy-ion collisions at and beyond SPS.

  1. Strongly coupled semidirect mediation of supersymmetry breaking

    International Nuclear Information System (INIS)

    Ibe, M.; Izawa, K.-I.; Nakai, Y.

    2009-01-01

    Strongly coupled semidirect gauge mediation models of supersymmetry breaking through massive mediators with standard-model charges are investigated by means of composite degrees of freedom. Sizable mediation is realized to generate the standard-model gaugino masses for a small mediator mass without breaking the standard-model symmetries.

  2. Strong Turbulence in Low-beta Plasmas

    DEFF Research Database (Denmark)

    Tchen, C. M.; Pécseli, Hans; Larsen, Søren Ejling

    1980-01-01

    An investigation of the spectral structure of turbulence in a plasma confined by a strong homogeneous magnetic field was made by means of a fluid description. The turbulent spectrum is divided into subranges. Mean gradients of velocity and density excite turbulent motions, and govern the production......-cathode reflex arc, Stellarator, Zeta discharge, ionospheric plasmas, and auroral plasma turbulence....

  3. Strong industrial base vital for economic revival

    CERN Multimedia

    2001-01-01

    At the inauguration of a 2-day conference on nuclear technology in Islamabad, the chairman of PAEC said that Pakistan needs to develop a strong industrial base and capability to export equipment to improve the economic condition of the country. He descibed how Pakistan has already had a breakthrough with the export of equipment to CERN, Geneva (1 page).

  4. Strong field control of predissociation dynamics.

    Science.gov (United States)

    Corrales, María E; Balerdi, Garikoitz; Loriot, Vincent; de Nalda, Rebeca; Bañares, Luis

    2013-01-01

    Strong field control scenarios are investigated in the CH3I predissociation dynamics at the origin of the second absorption B-band, in which state-selective electronic predissociation occurs through the crossing with a valence dissociative state. Dynamic Stark control (DSC) and pump-dump strategies are shown capable of altering both the predissociation lifetime and the product branching ratio.

  5. Bottomonia: open bottom strong decays and spectrum

    Directory of Open Access Journals (Sweden)

    Santopinto E.

    2014-05-01

    Full Text Available We present our results for the bottomonium spectrum with self energy corrections. The bare masses used in the calculation are computed within Godfrey and Isgur’s relativized quark model. We also discuss our results for the open bottom strong decay widths of higher bottomonia in the 3P0 pair-creation model.

  6. Strong and Reversible Monovalent Supramolecular Protein Immobilization

    NARCIS (Netherlands)

    Young, Jacqui F.; Nguyen, Hoang D.; Yang, Lanti; Huskens, Jurriaan; Jonkheijm, Pascal; Brunsveld, Luc

    2010-01-01

    Proteins with an iron clasp: Site-selective incorporation of a ferrocene molecule into a protein allows for easy, strong, and reversible supramolecular protein immobilization through a selective monovalent interaction of the ferrocene with a cucurbit[7]uril immobilized on a gold surface. The

  7. Steering neutral atoms in strong laser fields

    International Nuclear Information System (INIS)

    Eilzer, S; Eichmann, U

    2014-01-01

    The seminal strong-field tunnelling theory introduced by L V Keldysh plays a pivotal role. It has shaped our understanding of atomic strong-field processes, where it represents the first step in complex ionisation dynamics and provides reliable tunnelling rates. Tunnelling rates, however, cannot be necessarily equated with ionisation rates. Taking into account the electron dynamics in the Coulomb potential following the tunnelling process, the process of frustrated tunnelling ionisation has been found to lead to excited Rydberg atoms. Here, we excite He atoms in the strong-field tunnelling regime into Rydberg states. A high percentage of these Rydberg atoms survive in high intensity laser fields. We exploit this fact together with their high polarisability to kinematically manipulate the Rydberg atoms with a second elliptically polarised focused strong laser field. By varying the spatial overlap of the two laser foci, we are able to selectively control the deflection of the Rydberg atoms. The results of semi-classical calculations, which are based on the frustrated tunnelling model and on the ponderomotive acceleration, are in accord with our experimental data. (paper)

  8. Rotating compressible fluids under strong stratification

    Czech Academy of Sciences Publication Activity Database

    Feireisl, Eduard; Lu, Y.; Novotný, A.

    2014-01-01

    Roč. 19, October (2014), s. 11-18 ISSN 1468-1218 Keywords : rotating fluid * compressible Navier-Stokes * strong stratification Subject RIV: BA - General Mathematics Impact factor: 2.519, year: 2014 http://www.sciencedirect.com/science/article/pii/S1468121814000212#

  9. Spin Wave Theory of Strongly Anisotropic Magnets

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1977-01-01

    A strong anisotropy gives rise to a non-spherical precession of the spins with different amplitudes in the x and y directions. The highly anharmonic exchange interaction thereby becomes effectively anisotropic. The possibility of detecting a genuine two-ion anisotropy is discussed, and comments...

  10. Black holes and the strong cosmic censorship

    International Nuclear Information System (INIS)

    Krolak, A.

    1984-01-01

    The theory of black holes developed by Hawking in asymptotically flat space-times is generalized so that black holes in the cosmological situations are included. It is assumed that the strong version of the Penrose cosmic censorship hypothesis holds. (author)

  11. Patterns of strong coupling for LHC searches

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Da [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics,Chinese Academy of Sciences, Beijing, People’s Republic of (China); Theoretical Particle Physics Laboratory, Institute of Physics,EPFL, CH-1015 Lausanne (Switzerland); Pomarol, Alex [CERN, Theoretical Physics Department,1211 Geneva 23 (Switzerland); Dept. de Física and IFAE-BIST,Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Rattazzi, Riccardo [Theoretical Particle Physics Laboratory, Institute of Physics,EPFL, CH-1015 Lausanne (Switzerland); Riva, Francesco [CERN, Theoretical Physics Department,1211 Geneva 23 (Switzerland)

    2016-11-23

    Even though the Standard Model (SM) is weakly coupled at the Fermi scale, a new strong dynamics involving its degrees of freedom may conceivably lurk at slightly higher energies, in the multi TeV range. Approximate symmetries provide a structurally robust context where, within the low energy description, the dimensionless SM couplings are weak, while the new strong dynamics manifests itself exclusively through higher-derivative interactions. We present an exhaustive classification of such scenarios in the form of effective field theories, paying special attention to new classes of models where the strong dynamics involves, along with the Higgs boson, the SM gauge bosons and/or the fermions. The IR softness of the new dynamics suppresses its effects at LEP energies, but deviations are in principle detectable at the LHC, even at energies below the threshold for production of new states. We believe our construction provides the so far unique structurally robust context where to motivate several LHC searches in Higgs physics, diboson production, or WW scattering. Perhaps surprisingly, the interplay between weak coupling, strong coupling and derivatives, which is controlled by symmetries, can override the naive expansion in operator dimension, providing instances where dimension-8 dominates dimension-6, well within the domain of validity of the low energy effective theory. This result reveals the limitations of an analysis that is both ambitiously general and restricted to dimension-6 operators.

  12. Strong gravity effects in accreting black-hole systems

    International Nuclear Information System (INIS)

    Niedzwiecki, A.

    2006-01-01

    I briefly review current status of studying effects of strong gravity in X-ray astronomy. Matter accreting onto a black hole probes the relativistic region of space-time and the high-energy radiation it produces should contain signatures of strong gravity effects. Current X-ray observations provide the evidence that the observed emission originates, in some cases, at a distance of a few gravitational radii from a black hole. Moreover, certain observations invoke interpretations favouring rapid rotation of the black hole. Some observational properties of black hole systems are supposed to result from the lack of a material surface in these objects. I consider further effects, specific for the black hole environment, which can be studied in X-ray data. Bulk motion Comptonization, which would directly reveal converging flow of matter plunging into a black hole, is unlikely to be important in formation of X-ray spectra. Similarly, Penrose processes are unlikely to give observational effects, although this issue has not been thoroughly studied so far for all plausible radiative mechanisms. (author)

  13. Observations of strong ion-ion correlations in dense plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.; Fletcher, L.; Pak, A.; Chapman, D. A.; Falcone, R. W.; Fortmann, C.; Galtier, E.; Gericke, D. O.; Gregori, G.; Hastings, J.; Landen, O. L.; Le Pape, S.; Lee, H. J.; Nagler, B.; Neumayer, P.; Turnbull, D.; Vorberger, J.; White, T. G.; Wünsch, K.; Zastrau, U.; Glenzer, S. H.; Döppner, T.

    2014-05-01

    Using simultaneous spectrally, angularly, and temporally resolved x-ray scattering, we measure the pronounced ion-ion correlation peak in a strongly coupled plasma. Laser-driven shock-compressed aluminum at ~3× solid density is probed with high-energy photons at 17.9 keV created by molybdenum He-α emission in a laser-driven plasma source. The measured elastic scattering feature shows a well-pronounced correlation peak at a wave vector of k=4k=4Å-1. The magnitude of this correlation peak cannot be described by standard plasma theories employing a linear screened Coulomb potential. Advanced models, including a strong short-range repulsion due to the inner structure of the aluminum ions are however in good agreement with the scattering data. These studies have demonstrated a new highly accurate diagnostic technique to directly measure the state of compression and the ion-ion correlations. We have since applied this new method in single-shot wave-number resolved S(k) measurements to characterize the physical properties of dense plasmas.

  14. Stimulated secondary emission from semiconductor microcavities

    DEFF Research Database (Denmark)

    Østergaard, John Erland; Mizeikis, V.; Langbein, Wolfgang Werner

    2001-01-01

    We find strong influence of final-state stimulation on the time-resolved light emission dynamics from semiconductor microcavities after pulsed excitation allowing angle-resonant polariton-polariton scattering on the lower-polariton branch. The polariton dynamics can be controlled by injection...

  15. Eindhoven Airport : towards zero CO2 emissions

    NARCIS (Netherlands)

    Jorge Simoes Pedro, Joana

    2015-01-01

    Eindhoven airport is growing and it is strongly committed to take this opportunity to invest in innovative solutions for a sustainable development. Therefore, this document proposes a strategic plan for reaching Zero CO2 emissions at Eindhoven airport. This document proposes to reduce the CO2

  16. Strong drifts effects on neoclassical transport

    International Nuclear Information System (INIS)

    Tessarotto, M.; Gregoratto, D.; White, R.B.

    1996-01-01

    It is well known that strong drifts play an important role in plasma equilibrium, stability and confinement A significant example concerns, in particular for tokamak plasmas, the case of strong toroidal differential rotation produced by E x B drift which is currently regarded as potentially important for its influence in equilibrium, stability and transport. In fact, theoretically, it has been found that shear flow can substantially affect the stability of microinstabilities as well modify substantially transport. Recent experimental observations of enhanced confinement and transport regimes in Tokamaks, show, however, evidence of the existence of strong drifts in the plasma core. These are produced not only by the radial electric field [which gives rise to the E x B drift], but also by density [N s ], temperature [T s ] and mass flow [V = ωRe var-phi , with e var-phi the toroidal unit vector, R the distance for the symmetry axis of the torus and ω being the toroidal angular rotation velocity] profiles which are suitably steep. This implies that, in a significant part of the plasma core, the relevant scale lengths of the gradients [of N s , T s , ω], i.e., respectively L N , L T and L ω can be as large as the radial scale length characterizing the banana orbits, L b . Interestingly enough, the transport estimates obtained appear close or even lower than the predictions based on the simplest neoclassical model. However, as is well known, the latter applies, in a strict sense only in the case of weak drifts and also ignoring even the contribution of shear flow related to strong E x B drift. Thus a fundamental problem appears the extension of neoclassical transport theory to include the effect of strong drifts in Tokamak confinement systems. The goal of this investigation is to develop a general formulation of neoclassical transport embodying such important feature

  17. Super symmetry in strong and weak interactions

    International Nuclear Information System (INIS)

    Seshavatharam, U.V.S.; Lakshminarayana, S.

    2010-01-01

    For strong interaction two new fermion mass units 105.32 MeV and 11450 MeV are assumed. Existence of "Integral charge quark bosons", "Integral charge effective quark fermions", "Integral charge (effective) quark fermi-gluons" and "Integral charge quark boso-gluons" are assumed and their masses are estimated. It is noticed that, characteristic nuclear charged fermion is X s · 105.32 = 938.8 MeV and corresponding charged boson is X s (105.32/x) = 415.0 where X s = 8.914 is the inverse of the strong coupling constant and x = 2.26234 is a new number by using which "super symmetry" can be seen in "strong and weak" interactions. 11450 MeV fermion and its boson of mass = 11450/x = 5060 MeV plays a crucial role in "sub quark physics" and "weak interaction". 938.8 MeV strong fermion seems to be the proton. 415 MeV strong boson seems to be the mother of the presently believed 493,496 and 547 MeV etc, strange mesons. With 11450 MeV fermion "effective quark-fermi-gluons" and with 5060 MeV boson "quark boso-gluon masses" are estimated. "Effective quark fermi-gluons" plays a crucial role in ground state charged baryons mass generation. Light quark bosons couple with these charged baryons to form doublets and triplets. "Quark boso-gluons" plays a crucial role in ground state neutral and charged mesons mass generation. Fine and super-fine rotational levels can be given by [I or (I/2)] power(1/4) and [I or (I/2)] power(1/12) respectively. Here, I = n(n+1) and n = 1, 2, 3, … (author)

  18. 150 Years of Italian CO2 Emissions and Economic Growth

    DEFF Research Database (Denmark)

    Annicchiarico, Barbara; Bennato, Anna Rita; Chini, Emilio Zanetti

    This paper examines the relationship between economic growth and carbon dioxide emissions in Italy considering the developments in a 150-year time span. Using several statistical techniques, we find that GDP growth and carbon dioxide emissions are strongly interrelated, with a dramatic change...

  19. Strong dynamics and lattice gauge theory

    Science.gov (United States)

    Schaich, David

    In this dissertation I use lattice gauge theory to study models of electroweak symmetry breaking that involve new strong dynamics. Electroweak symmetry breaking (EWSB) is the process by which elementary particles acquire mass. First proposed in the 1960s, this process has been clearly established by experiments, and can now be considered a law of nature. However, the physics underlying EWSB is still unknown, and understanding it remains a central challenge in particle physics today. A natural possibility is that EWSB is driven by the dynamics of some new, strongly-interacting force. Strong interactions invalidate the standard analytical approach of perturbation theory, making these models difficult to study. Lattice gauge theory is the premier method for obtaining quantitatively-reliable, nonperturbative predictions from strongly-interacting theories. In this approach, we replace spacetime by a regular, finite grid of discrete sites connected by links. The fields and interactions described by the theory are likewise discretized, and defined on the lattice so that we recover the original theory in continuous spacetime on an infinitely large lattice with sites infinitesimally close together. The finite number of degrees of freedom in the discretized system lets us simulate the lattice theory using high-performance computing. Lattice gauge theory has long been applied to quantum chromodynamics, the theory of strong nuclear interactions. Using lattice gauge theory to study dynamical EWSB, as I do in this dissertation, is a new and exciting application of these methods. Of particular interest is non-perturbative lattice calculation of the electroweak S parameter. Experimentally S ≈ -0.15(10), which tightly constrains dynamical EWSB. On the lattice, I extract S from the momentum-dependence of vector and axial-vector current correlators. I created and applied computer programs to calculate these correlators and analyze them to determine S. I also calculated the masses

  20. Emissions Modeling Clearinghouse

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Emissions Modeling Clearinghouse (EMCH) supports and promotes emissions modeling activities both internal and external to the EPA. Through this site, the EPA...

  1. National Emission Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Emission Inventory contains measured, modeled, and estimated data for emissions of all known source categories in the US (stationary sources, fires,...

  2. Emissions Trading Resources

    Science.gov (United States)

    Learn about emissions trading programs, also known as cap and trade programs, which are market-based policy tools for protecting human health and the environment by controlling emissions from a group of sources.

  3. What Is Emissions Trading?

    Science.gov (United States)

    Learn the basics about how emissions trading uses a market-based policy tool used to control large amounts of pollution emissions from a group of sources in order to protect human health and the environment.

  4. World Emission RETRO ANTHRO

    Data.gov (United States)

    Washington University St Louis — Anthropogenic and vegetation fire emissions data were generated monthly covering a period of 1960 to 2000. Anthropogenic emissions in the RETRO inventory are derived...

  5. Emissions & Measurements - Black Carbon

    Science.gov (United States)

    Emissions and Measurement (EM) research activities performed within the National Risk Management Research Lab NRMRL) of EPA's Office of Research and Development (ORD) support measurement and laboratory analysis approaches to accurately characterize source emissions, and near sour...

  6. Biodiesel Emissions Analysis Program

    Science.gov (United States)

    Using existing data, the EPA's biodiesel emissions analysis program sought to quantify the air pollution emission effects of biodiesel for diesel engines that have not been specifically modified to operate on biodiesel.

  7. Dioxin emissions and sources

    International Nuclear Information System (INIS)

    1994-01-01

    The papers presented at the seminar discussed dioxin emissions and sources, dioxin pollution of soils, waste water and sewage sludge, stocktaking of emission sources, and exposure and risk analyses for dioxin and other pollutants. (EF) [de

  8. National Emission Information System

    International Nuclear Information System (INIS)

    Sajtakova, E.; Spisakova, K.

    2005-01-01

    In this presentation the Slovak National Emission Information System (NEIS) is presented. The NEIS represents hierarchical oriented modular system of acquisition, verification, saving and reporting of data about annual emissions and payments for pollution of atmosphere

  9. Fast Atom Ionization in Strong Electromagnetic Radiation

    Science.gov (United States)

    Apostol, M.

    2018-05-01

    The Goeppert-Mayer and Kramers-Henneberger transformations are examined for bound charges placed in electromagnetic radiation in the non-relativistic approximation. The consistent inclusion of the interaction with the radiation field provides the time evolution of the wavefunction with both structural interaction (which ensures the bound state) and electromagnetic interaction. It is shown that in a short time after switching on the high-intensity radiation the bound charges are set free. In these conditions, a statistical criterion is used to estimate the rate of atom ionization. The results correspond to a sudden application of the electromagnetic interaction, in contrast with the well-known ionization probability obtained by quasi-classical tunneling through classically unavailable non-stationary states, or other equivalent methods, where the interaction is introduced adiabatically. For low-intensity radiation the charges oscillate and emit higher-order harmonics, the charge configuration is re-arranged and the process is resumed. Tunneling ionization may appear in these circumstances. Extension of the approach to other applications involving radiation-induced charge emission from bound states is discussed, like ionization of molecules, atomic clusters or proton emission from atomic nuclei. Also, results for a static electric field are included.

  10. Coherent emission mechanisms in astrophysical plasmas

    Science.gov (United States)

    Melrose, D. B.

    2017-12-01

    Three known examples of coherent emission in radio astronomical sources are reviewed: plasma emission, electron cyclotron maser emission (ECME) and pulsar radio emission. Plasma emission is a multi-stage mechanism with the first stage being generation of Langmuir waves through a streaming instability, and subsequent stages involving partial conversion of the Langmuir turbulence into escaping radiation at the fundamental (F) and second harmonic (H) of the plasma frequency. The early development and subsequent refinements of the theory, motivated by application to solar radio bursts, are reviewed. The driver of the instability is faster electrons outpacing slower electrons, resulting in a positive gradient ({d}f(v_allel )/{d}v_allel >0) at the front of the beam. Despite many successes of the theory, there is no widely accepted explanation for type I bursts and various radio continua. The earliest models for ECME were purely theoretical, and the theory was later adapted and applied to Jupiter (DAM), the Earth (AKR), solar spike bursts and flare stars. ECME strongly favors the x mode, whereas plasma emission favors the o mode. Two drivers for ECME are a ring feature (implying {d}f(v)/{d}v>0) and a loss-cone feature. Loss-cone-driven ECME was initially favored for all applications. The now favored driver for AKR is the ring-feature in a horseshoe distribution, which results from acceleration by a parallel electric on converging magnetic field lines. The driver in DAM and solar and stellar applications is uncertain. The pulsar radio emission mechanism remains an enigma. Ingredients needed in discussing possible mechanisms are reviewed: general properties of pulsars, pulsar electrodynamics, the properties of pulsar plasma and wave dispersion in such plasma. Four specific emission mechanisms (curvature emission, linear acceleration emission, relativistic plasma emission and anomalous Doppler emission) are discussed and it is argued that all encounter difficulties. Coherent

  11. Blue Emission in Proteins

    OpenAIRE

    Sarkar, Sohini; Sengupta, Abhigyan; Hazra, Partha; Mandal, Pankaj

    2014-01-01

    Recent literatures reported blue-green emission from amyloid fibril as exclusive signature of fibril formation. This unusual visible luminescence is regularly used to monitor fibril growth. Blue-green emission has also been observed in crystalline protein and in solution. However, the origin of this emission is not known exactly. Our spectroscopic study of serum proteins reveals that the blue-green emission is a property of protein monomer. Evidences suggest that semiconductor-like band struc...

  12. Waves in strong centrifugal fields: dissipationless gas

    Science.gov (United States)

    Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

    2015-04-01

    Linear waves are investigated in a rotating gas under the condition of strong centrifugal acceleration of the order 106 g realized in gas centrifuges for separation of uranium isotopes. Sound waves split into three families of the waves under these conditions. Dispersion equations are obtained. The characteristics of the waves strongly differ from the conventional sound waves on polarization, velocity of propagation and distribution of energy of the waves in space for two families having frequencies above and below the frequency of the conventional sound waves. The energy of these waves is localized in rarefied region of the gas. The waves of the third family were not specified before. They propagate exactly along the rotational axis with the conventional sound velocity. These waves are polarized only along the rotational axis. Radial and azimuthal motions are not excited. Energy of the waves is concentrated near the wall of the rotor where the density of the gas is largest.

  13. Hydrogen atoms in a strong magnetic field

    International Nuclear Information System (INIS)

    Santos, R.R. dos.

    1975-07-01

    The energies and wave functions of the 14 lowest states of a Hydrogen atom in a strong magnetic field are calculated, using a variational scheme. The equivalence between the atomic problem and the problems related with excitons and impurities in semiconductors in the presence of a strong magnetic field are shown. The calculations of the energies and wave functions have been divided in two regions: the first, for the magnetic field ranging between zero and 10 9 G; in the second the magnetic field ranges between 10 9 and 10 11 G. The results have been compared with those obtained by previous authors. The computation time necessary for the calculations is small. Therefore this is a convenient scheme to obtain the energies and wave functions for the problem. Transition probabilities, wavelengths and oscillator strengths for some allowed transitions are also calculated. (Author) [pt

  14. Strongly not relatives Kähler manifolds

    Directory of Open Access Journals (Sweden)

    Zedda Michela

    2017-02-01

    Full Text Available In this paper we study Kähler manifolds that are strongly not relative to any projective Kähler manifold, i.e. those Kähler manifolds that do not share a Kähler submanifold with any projective Kähler manifold even when their metric is rescaled by the multiplication by a positive constant. We prove two results which highlight some relations between this property and the existence of a full Kähler immersion into the infinite dimensional complex projective space. As application we get that the 1-parameter families of Bergman-Hartogs and Fock-Bargmann-Hartogs domains are strongly not relative to projective Kähler manifolds.

  15. Strong ground motion prediction using virtual earthquakes.

    Science.gov (United States)

    Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C

    2014-01-24

    Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion.

  16. Analytical solution of strongly nonlinear Duffing oscillators

    Directory of Open Access Journals (Sweden)

    A.M. El-Naggar

    2016-06-01

    Full Text Available In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε is defined such that the value of α is always small regardless of the magnitude of the original parameter ε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to α. Approximate solution obtained by the present method is compared with the solution of energy balance method, homotopy perturbation method, global error minimization method and lastly numerical solution. We observe from the results that this method is very simple, easy to apply, and gives a very good accuracy not only for small parameter εbut also for large values of ε.

  17. Cosmogenic photons strongly constrain UHECR source models

    Directory of Open Access Journals (Sweden)

    van Vliet Arjen

    2017-01-01

    Full Text Available With the newest version of our Monte Carlo code for ultra-high-energy cosmic ray (UHECR propagation, CRPropa 3, the flux of neutrinos and photons due to interactions of UHECRs with extragalactic background light can be predicted. Together with the recently updated data for the isotropic diffuse gamma-ray background (IGRB by Fermi LAT, it is now possible to severely constrain UHECR source models. The evolution of the UHECR sources especially plays an important role in the determination of the expected secondary photon spectrum. Pure proton UHECR models are already strongly constrained, primarily by the highest energy bins of Fermi LAT’s IGRB, as long as their number density is not strongly peaked at recent times.

  18. New strong interactions above the electroweak scale

    International Nuclear Information System (INIS)

    White, A.R.

    1994-01-01

    Theoretical arguments for a new higher-color quark sector, based on Pomeron physics in QCD, are briefly described. The electroweak symmetry-breaking, Strong CP conservation, and electroweak scale CP violation, that is naturally produced by this sector is also outlined. A further consequence is that above the electroweak scale there will be a radical change in the strong interaction. Electroweak states, in particular multiple W's and Z's, and new, semi-stable, very massive, baryons, will be commonly produced. The possible correlation of expected phenomena with a wide range of observed Cosmic Ray effects at and above the primary spectrum knee is described. Related phenomena that might be seen in the highest energy hard scattering events at the Fermilab Tevatron, some of which could be confused with top production, are also briefly discussed

  19. Quantum strongly secure ramp secret sharing

    DEFF Research Database (Denmark)

    Zhang, Paul; Matsumoto, Rytaro Yamashita

    2015-01-01

    Quantum secret sharing is a scheme for encoding a quantum state (the secret) into multiple shares and distributing them among several participants. If a sufficient number of shares are put together, then the secret can be fully reconstructed. If an insufficient number of shares are put together...... however, no information about the secret can be revealed. In quantum ramp secret sharing, partial information about the secret is allowed to leak to a set of participants, called an unqualified set, that cannot fully reconstruct the secret. By allowing this, the size of a share can be drastically reduced....... This paper introduces a quantum analog of classical strong security in ramp secret sharing schemes. While the ramp secret sharing scheme still leaks partial information about the secret to unqualified sets of participants, the strong security condition ensures that qudits with critical information can...

  20. Quantum Transport in Strongly Correlated Systems

    DEFF Research Database (Denmark)

    Bohr, Dan

    2007-01-01

    the density matrix renormalization group (DMRG) method. We present two DMRG setups for calculating the linear conductance of strongly correlated nanostructures in the infinitesimal source-drain voltage regime. The first setup describes the leads by modified real-space tight-binding chains, whereas the second....... Thus both coherence and correlation effects are important in this model, and the methods applied should be able to handle both these effects rigorously. We present the DMRG setup for this model and benchmark against existing Greens function results for the model. Then we present initial DMRG results...... screening plays a much less significant role than in bulk systems due to the reduced size of the objects, therefore making it necessary to consider the importance of correlations between electrons. The work presented in this thesis deals with quantum transport through strongly correlated systems using...

  1. Equilibrium and stability in strongly inhomogeneous plasmas

    International Nuclear Information System (INIS)

    Mynick, H.E.

    1978-10-01

    The equilibrium of strongly inhomogeneous, collisionless, slab plasmas, is studied using a generalized version of a formalism previously developed, which permits the generation of self-consistent equilibria, for plasmas with arbitrary magnetic shear, and variation of magnetic field strength. A systematic procedure is developed for deriving the form of the guiding-center Hamiltonian K, for finite eta, in an axisymmetric geometry. In the process of obtaining K, an expression for the first adiabatic invariant (the gyroaction) is obtained, which generalizes the usual expression 1/2 mv/sub perpendicular/ 2 /Ω/sub c/ (Ω/sub c/ = eB/mc), to finite eta and magnetic shear. A formalism is developed for the study of the stability of strongly-inhomogeneous, magnetized slab plasmas; it is then applied to the ion-drift-cyclotron instability

  2. Orbits in weak and strong bars

    CERN Document Server

    Contopoulos, George

    1980-01-01

    The authors study the plane orbits in simple bar models embedded in an axisymmetric background when the bar density is about 1% (weak), 10% (intermediate) or 100% (strong bar) of the axisymmetric density. Most orbits follow the stable periodic orbits. The basic families of periodic orbits are described. In weak bars with two Inner Lindblad Resonances there is a family of stable orbits extending from the center up to the Outer Lindblad Resonance. This family contains the long period orbits near corotation. Other stable families appear between the Inner Lindblad Resonances, outside the Outer Lindblad Resonance, around corotation (short period orbits) and around the center (retrograde). Some families become unstable or disappear in strong bars. A comparison is made with cases having one or no Inner Lindblad Resonance. (12 refs).

  3. Marital Expectations in Strong African American Marriages.

    Science.gov (United States)

    Vaterlaus, J Mitchell; Skogrand, Linda; Chaney, Cassandra; Gahagan, Kassandra

    2017-12-01

    The current exploratory study utilized a family strengths framework to identify marital expectations in 39 strong African American heterosexual marriages. Couples reflected on their marital expectations over their 10 or more years of marriage. Three themes emerged through qualitative analysis and the participants' own words were used in the presentation of the themes. African Americans indicated that there was growth in marital expectations over time, with marital expectations often beginning with unrealistic expectations that grew into more realistic expectations as their marriages progressed. Participants also indicated that core expectations in strong African American marriages included open communication, congruent values, and positive treatment of spouse. Finally, participants explained there is an "I" in marriage as they discussed the importance of autonomy within their marital relationships. Results are discussed in association with existing research and theory. © 2016 Family Process Institute.

  4. Strong spin-photon coupling in silicon

    Science.gov (United States)

    Samkharadze, N.; Zheng, G.; Kalhor, N.; Brousse, D.; Sammak, A.; Mendes, U. C.; Blais, A.; Scappucci, G.; Vandersypen, L. M. K.

    2018-03-01

    Long coherence times of single spins in silicon quantum dots make these systems highly attractive for quantum computation, but how to scale up spin qubit systems remains an open question. As a first step to address this issue, we demonstrate the strong coupling of a single electron spin and a single microwave photon. The electron spin is trapped in a silicon double quantum dot, and the microwave photon is stored in an on-chip high-impedance superconducting resonator. The electric field component of the cavity photon couples directly to the charge dipole of the electron in the double dot, and indirectly to the electron spin, through a strong local magnetic field gradient from a nearby micromagnet. Our results provide a route to realizing large networks of quantum dot–based spin qubit registers.

  5. Electrons in a strong magnetic field

    International Nuclear Information System (INIS)

    Itzykson, C.

    1985-05-01

    We first describe the average one-particle spectrum in the presence of a strong magnetic field together with random impurities for a Gaussian distribution, and generalized using a supersymmetric method. We then study the effect of Coulomb interactions on an electron gas in a strong field, within the approximation of a projection on the lowest Landau level. At maximal density (or filling fraction ν equal to unity) the quantum mechanical problem is equivalent to a soluble classical model for a two-dimensional plasma. As ν decreases, more states come into play. Laughlin has guessed the structure of the ground state and its low lying excitations for certain rational values of the filling fraction. A complete proof is however missing, nor is it clear what happens as ν becomes so small that a ''crystalline'' structure becomes favoured. Our presentation shows a link with functions occurring in combinatorics and analytic number theory, which seems not to have been fully exploited

  6. Magnetic properties of strongly asymmetric nuclear matter

    International Nuclear Information System (INIS)

    Kutschera, M.; Wojcik, W.

    1988-01-01

    We investigate stability of neutron matter containing a small proton admixture with respect to spin fluctuations. We establish conditions under which strongly asymmetric nuclear matter could acquire a permanent magnetization. It is shown that if the protons are localized, the system becomes unstable to spin fluctuations for arbitrarily weak proton-neutron spin interactions. For non-localized protons there exists a threshold value of the spin interaction above which the system can develop a spontaneous polarization. 12 refs., 2 figs. (author)

  7. Strong coupling analogue of the Born series

    International Nuclear Information System (INIS)

    Dolinszky, T.

    1989-10-01

    In a given partial wave, the strength of the centrifugal term to be incorporated into the WKBA solutions in different spatial regions can be adjusted so as to make the first order wave functions everywhere smooth and, in strong coupling, exactly reproduce Quantum Mechanics throughout the space. The relevant higher order approximations supply an absolute convergent series expansion of the exact scattering state. (author) 4 refs.; 2 figs.; 2 tabs

  8. Strong disorder RG approach of random systems

    International Nuclear Information System (INIS)

    Igloi, Ferenc; Monthus, Cecile

    2005-01-01

    There is a large variety of quantum and classical systems in which the quenched disorder plays a dominant ro-circumflex le over quantum, thermal, or stochastic fluctuations: these systems display strong spatial heterogeneities, and many averaged observables are actually governed by rare regions. A unifying approach to treat the dynamical and/or static singularities of these systems has emerged recently, following the pioneering RG idea by Ma and Dasgupta and the detailed analysis by Fisher who showed that the Ma-Dasgupta RG rules yield asymptotic exact results if the broadness of the disorder grows indefinitely at large scales. Here we report these new developments by starting with an introduction of the main ingredients of the strong disorder RG method. We describe the basic properties of infinite disorder fixed points, which are realized at critical points, and of strong disorder fixed points, which control the singular behaviors in the Griffiths-phases. We then review in detail applications of the RG method to various disordered models, either (i) quantum models, such as random spin chains, ladders and higher dimensional spin systems, or (ii) classical models, such as diffusion in a random potential, equilibrium at low temperature and coarsening dynamics of classical random spin chains, trap models, delocalization transition of a random polymer from an interface, driven lattice gases and reaction diffusion models in the presence of quenched disorder. For several one-dimensional systems, the Ma-Dasgupta RG rules yields very detailed analytical results, whereas for other, mainly higher dimensional problems, the RG rules have to be implemented numerically. If available, the strong disorder RG results are compared with another, exact or numerical calculations

  9. Strong, Ductile Rotor For Cryogenic Flowmeters

    Science.gov (United States)

    Royals, W. T.

    1993-01-01

    Improved magnetic flowmeter rotor resists cracking at cryogenic temperatures, yet provides adequate signal to magnetic pickup outside flowmeter housing. Consists mostly of stainless-steel alloy 347, which is ductile and strong at low temperatures. Small bead of stainless-steel alloy 410 welded in groove around circumference of round bar of stainless-steel alloy 347; then rotor machined from bar. Tips of rotor blades contain small amounts of magnetic alloy, and passage of tips detected.

  10. Hemingway's Scar and His Strong Will

    Institute of Scientific and Technical Information of China (English)

    许颖

    2009-01-01

    Hemingway's inner world is not balanced He had a strong will,and on the other hand,he is hurt severely.Based on the analysis of Hemingway's experience and his works,the paper aims to study Hemingway's life attitude:Men,all sooner or later,go down to defeat:it is how they face the ordeal that determines their status.

  11. Strongly stable real infinitesimally symplectic mappings

    NARCIS (Netherlands)

    Cushman, R.; Kelley, A.

    We prove that a mapA εsp(σ,R), the set of infinitesimally symplectic maps, is strongly stable if and only if its centralizerC(A) insp(σ,R) contains only semisimple elements. Using the theorem that everyB insp(σ,R) close toA is conjugate by a real symplectic map to an element ofC(A), we give a new

  12. Electromotive force in strongly compressible magnetohydrodynamic turbulence

    Science.gov (United States)

    Yokoi, N.

    2017-12-01

    Variable density fluid turbulence is ubiquitous in geo-fluids, not to mention in astrophysics. Depending on the source of density variation, variable density fluid turbulence may be divided into two categories: the weak compressible (entropy mode) turbulence for slow flow and the strong compressible (acoustic mode) turbulence for fast flow. In the strong compressible turbulence, the pressure fluctuation induces a strong density fluctuation ρ ', which is represented by the density variance ( denotes the ensemble average). The turbulent effect on the large-scale magnetic-field B induction is represented by the turbulent electromotive force (EMF) (u': velocity fluctuation, b': magnetic-field fluctuation). In the usual treatment in the dynamo theory, the expression for the EMF has been obtained in the framework of incompressible or weak compressible turbulence, where only the variation of the mean density , if any, is taken into account. We see from the equation of the density fluctuation ρ', the density variance is generated by the large mean density variation ∂ coupled with the turbulent mass flux . This means that in the region where the mean density steeply changes, the density variance effect becomes relevant for the magnetic field evolution. This situation is typically the case for phenomena associated with shocks and compositional discontinuities. With the aid of the analytical theory of inhomogeneous compressible magnetohydrodynamic (MHD) turbulence, the expression for the turbulent electromotive force is investigated. It is shown that, among others, an obliqueness (misalignment) between the mean density gradient ∂ and the mean magnetic field B may contribute to the EMF as ≈χ B×∂ with the turbulent transport coefficient χ proportional to the density variance (χ ). This density variance effect is expected to strongly affect the EMF near the interface, and changes the transport properties of turbulence. In the case of an interface under the MHD slow

  13. Strong beam production for some elements

    International Nuclear Information System (INIS)

    Camplan, J.; Chaumont, J.; Meunier, R.

    1974-01-01

    Three electromagnetic isotope separators are installed in Rene Bernas Laboratory, one being especially adapted to ion implantation. The three apparatus use the same type of ion source and system of beam extraction. The special ion source is distinguishable from the others only by its smaller dimensions. These sources allow strong currents to be obtained for almost every element. The source and its extraction system are briefly described, examples of beams obtained are given [fr

  14. Emission computed tomography

    International Nuclear Information System (INIS)

    Ott, R.J.

    1986-01-01

    Emission Computed Tomography is a technique used for producing single or multiple cross-sectional images of the distribution of radionuclide labelled agents in vivo. The techniques of Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) are described with particular regard to the function of the detectors used to produce images and the computer techniques used to build up images. (UK)

  15. Simulation of turbulent flows containing strong shocks

    International Nuclear Information System (INIS)

    Fryxell, Bruce; Menon, Suresh

    2008-01-01

    Simulation of turbulent flows with strong shocks is a computationally challenging problem. The requirements for a method to produce accurate results for turbulence are orthogonal to those needed to treat shocks properly. In order to prevent an unphysical rate of decay of turbulent structures, it is necessary to use a method with very low numerical dissipation. Because of this, central difference schemes are widely used. However, computing strong shocks with a central difference scheme can produce unphysical post-shock oscillations that corrupt the entire flow unless additional dissipation is added. This dissipation can be difficult to localize to the area near the shock and can lead to inaccurate treatment of the turbulence. Modern high-resolution shock-capturing methods usually use upwind algorithms to provide the dissipation necessary to stabilize shocks. However, this upwind dissipation can also lead to an unphysical rate of decay of the turbulence. This paper discusses a hybrid method for simulating turbulent flows with strong shocks that couples a high-order central difference scheme with a high-resolution shock-capturing method. The shock-capturing method is used only in the vicinity of discontinuities in the flow, whereas the central difference scheme is used in the remainder of the computational domain. Results of this new method will be shown for a variety of test problems. Preliminary results for a realistic application involving detonation in gas-particle flows will also be presented.

  16. Transport phenomena in strongly correlated Fermi liquids

    International Nuclear Information System (INIS)

    Kontani, Hiroshi

    2013-01-01

    Comprehensive overview. Written by an expert of this topic. Provides the reader with current developments in the field. In conventional metals, various transport coefficients are scaled according to the quasiparticle relaxation time, τ, which implies that the relaxation time approximation (RTA) holds well. However, such a simple scaling does not hold in many strongly correlated electron systems, reflecting their unique electronic states. The most famous example would be cuprate high-Tc superconductors (HTSCs), where almost all the transport coefficients exhibit a significant deviation from the RTA results. To better understand the origin of this discrepancy, we develop a method for calculating various transport coefficients beyond the RTA by employing field theoretical techniques. Near the magnetic quantum critical point, the current vertex correction (CVC), which describes the electron-electron scattering beyond the relaxation time approximation, gives rise to various anomalous transport phenomena. We explain anomalous transport phenomena in cuprate HTSCs and other metals near their magnetic or orbital quantum critical point using a uniform approach. We also discuss spin related transport phenomena in strongly correlated systems. In many d- and f-electron systems, the spin current induced by the spin Hall effect is considerably greater because of the orbital degrees of freedom. This fact attracts much attention due to its potential application in spintronics. We discuss various novel charge, spin and heat transport phenomena in strongly correlated metals.

  17. Strong CP, flavor, and twisted split fermions

    International Nuclear Information System (INIS)

    Harnik, Roni; Perez, Gilad; Schwartz, Matthew D.; Shirman, Yuri

    2005-01-01

    We present a natural solution to the strong CP problem in the context of split fermions. By assuming CP is spontaneously broken in the bulk, a weak CKM phase is created in the standard model due to a twisting in flavor space of the bulk fermion wavefunctions. But the strong CP phase remains zero, being essentially protected by parity in the bulk and CP on the branes. As always in models of spontaneous CP breaking, radiative corrections to theta bar from the standard model are tiny, but even higher dimension operators are not that dangerous. The twisting phenomenon was recently shown to be generic, and not to interfere with the way that split fermions naturally weaves small numbers into the standard model. It follows that out approach to strong CP is compatible with flavor, and we sketch a comprehensive model. We also look at deconstructed version of this setup which provides a viable 4D model of spontaneous CP breaking which is not in the Nelson-Barr class. (author)

  18. Prevention of strong earthquakes: Goal or utopia?

    Science.gov (United States)

    Mukhamediev, Sh. A.

    2010-11-01

    In the present paper, we consider ideas suggesting various kinds of industrial impact on the close-to-failure block of the Earth’s crust in order to break a pending strong earthquake (PSE) into a number of smaller quakes or aseismic slips. Among the published proposals on the prevention of a forthcoming strong earthquake, methods based on water injection and vibro influence merit greater attention as they are based on field observations and the results of laboratory tests. In spite of this, the cited proofs are, for various reasons, insufficient to acknowledge the proposed techniques as highly substantiated; in addition, the physical essence of these methods has still not been fully understood. First, the key concept of the methods, namely, the release of the accumulated stresses (or excessive elastic energy) in the source region of a forthcoming strong earthquake, is open to objection. If we treat an earthquake as a phenomenon of a loss in stability, then, the heterogeneities of the physicomechanical properties and stresses along the existing fault or its future trajectory, rather than the absolute values of stresses, play the most important role. In the present paper, this statement is illustrated by the classical examples of stable and unstable fractures and by the examples of the calculated stress fields, which were realized in the source regions of the tsunamigenic earthquakes of December 26, 2004 near the Sumatra Island and of September 29, 2009 near the Samoa Island. Here, just before the earthquakes, there were no excessive stresses in the source regions. Quite the opposite, the maximum shear stresses τmax were close to their minimum value, compared to τmax in the adjacent territory. In the present paper, we provide quantitative examples that falsify the theory of the prevention of PSE in its current form. It is shown that the measures for the prevention of PSE, even when successful for an already existing fault, can trigger or accelerate a catastrophic

  19. The INGV Real Time Strong Motion Database

    Science.gov (United States)

    Massa, Marco; D'Alema, Ezio; Mascandola, Claudia; Lovati, Sara; Scafidi, Davide; Gomez, Antonio; Carannante, Simona; Franceschina, Gianlorenzo; Mirenna, Santi; Augliera, Paolo

    2017-04-01

    The INGV real time strong motion data sharing is assured by the INGV Strong Motion Database. ISMD (http://ismd.mi.ingv.it) was designed in the last months of 2011 in cooperation among different INGV departments, with the aim to organize the distribution of the INGV strong-motion data using standard procedures for data acquisition and processing. The first version of the web portal was published soon after the occurrence of the 2012 Emilia (Northern Italy), Mw 6.1, seismic sequence. At that time ISMD was the first European real time web portal devoted to the engineering seismology community. After four years of successfully operation, the thousands of accelerometric waveforms collected in the archive need necessary a technological improvement of the system in order to better organize the new data archiving and to make more efficient the answer to the user requests. ISMD 2.0 was based on PostgreSQL (www.postgresql.org), an open source object- relational database. The main purpose of the web portal is to distribute few minutes after the origin time the accelerometric waveforms and related metadata of the Italian earthquakes with ML≥3.0. Data are provided both in raw SAC (counts) and automatically corrected ASCII (gal) formats. The web portal also provide, for each event, a detailed description of the ground motion parameters (i.e. Peak Ground Acceleration, Velocity and Displacement, Arias and Housner Intensities) data converted in velocity and displacement, response spectra up to 10.0 s and general maps concerning the recent and the historical seismicity of the area together with information about its seismic hazard. The focal parameters of the events are provided by the INGV National Earthquake Center (CNT, http://cnt.rm.ingv.it). Moreover, the database provides a detailed site characterization section for each strong motion station, based on geological, geomorphological and geophysical information. At present (i.e. January 2017), ISMD includes 987 (121

  20. 77 FR 16131 - Establishing a White House Council on Strong Cities, Strong Communities

    Science.gov (United States)

    2012-03-20

    ... Order 13602 of March 15, 2012 Establishing a White House Council on Strong Cities, Strong Communities By... enable them to develop and implement economic strategies to become more competitive, sustainable, and... resources to develop and implement their economic vision and strategies. Sec. 2. White House Council on...

  1. Numerical Calculation of the Phase Space Density for the Strong-Strong Beam-Beam Interaction

    International Nuclear Information System (INIS)

    Sobol, A.; Ellison, J.A.

    2003-01-01

    We developed a parallel code to calculate the evolution of the 4D phase space density of two colliding beams, which are coupled via the collective strong-strong beam-beam interaction, in the absence of diffusion and damping, using the Perron-Frobenius (PF) operator technique

  2. Engaging Military Fathers in a Reflective Parenting Program: Lessons from Strong Families Strong Forces

    Science.gov (United States)

    DeVoe, Ellen R.; Paris, Ruth

    2015-01-01

    Through Strong Families Strong Forces, a reflective parenting program for military families with young children, we were privileged to work with contemporary military fathers who served in the post-9/11 conflicts in Afghanistan and Iraq. Due to this work, the authors gained valuable insight into the complexity of fathering during wartime, the…

  3. Study of luminous emissions associated to electron emissions in radiofrequency cavities; Etude des emissions lumineuses associees aux emissions electroniques dans les cavites hyperfrequences

    Energy Technology Data Exchange (ETDEWEB)

    Maissa, S

    1996-11-26

    This study investigates luminous emissions simultaneously to electron emissions and examines their features in order to better understand the field electron emission phenomenon. A RF cavity, operating at room temperature and in pulsed mode, joined to a sophisticated experimental apparatus has been especially developed. The electron and luminous emissions are investigated on cleaned or with metallic, graphitic and dielectric particles contaminated RF surfaces in order to study their influence on these phenomena. During the surface processing, unstable luminous spots glowing during one RF pulse are detected. Their apparition is promoted in the vicinity of the metallic particles or scratches. Two hypotheses could explain their origin: the presence of micro-plasmas associated to electronic explosive emission during processing or the thermal radiation of the melted metal during this emission. Stable luminous spots glowing during several RF pulses are also detected and appear to increase on RF surfaces contaminated with dielectric particles, leading to strong and explosive luminous emissions. Two interpretations are considered: the initiation of surface breakdowns on the dielectric particles or the heating by the RF field at temperatures sufficiently intense to provoke their thermal radiation then their explosion. Finally a superconducting cavity has been adapted to observe luminous spots, which differ from the former ones bu their star shape and could be associated to micro-plasmas, revealed by the starbursts observed on superconducting cavity walls. (author) 102 refs.

  4. Electroplex emission of the blend film of PVK and DPVBi

    Science.gov (United States)

    Li, Junming; Xu, Zheng; Zhang, Fujun; Zhao, Suling; Song, Dandan; Zhu, Haina; Song, Jinglu; Wang, Yongsheng; Xu, Xurong

    2010-04-01

    Influences of electric fields on the emission from organic light-emitting diodes (OLEDs) based on poly(N-vinylcarbazole) (PVK) and 4‧-bis(2-2diphenylvinyl)-1,1‧-biphenyl (DPVBi) as the active emission layer are studied. Electroluminescence (EL) spectra of PVK:DPVBi (1:1 w/w) films show one new emission peak locating at 640 nm compared with its photoluminescence (PL) spectra. There may be exists an electroplex emission between the PVK and DPVBi under high electric field strength. The emission intensity of peaking at 640 nm strongly depends on the driving voltage, and the ratio of electroplex emission intensity to exciton emission intensity (Ielectroplex/Iexciton) increases with the increase of driving voltage.

  5. Transmission coefficents in strongly deformed nuclei

    International Nuclear Information System (INIS)

    Aleshin, V.P.

    1996-01-01

    By using our semiclassical approach to particle evaporation from deformed nuclei developed earlier, we analyze here the heuristic methods of taking into account the effects of shape deformations on particle emission. These methods are based on the 'local' transmission coefficients in which the effective barrier depends on the angle with respect to the symmetry axis. The calculations revealed that the heuristic models are reasonable for particle energy spectra but fail, at large deformations, to describe the angular distributions. In A∼160 nuclei with axis ratio in the vicinity of 2:1 at temperatures of 2-3 MeV, the W (90 )/W(0 ) anisotropies of α particles with respect to the nuclear spin are 1.5 to 3 times larger than our approach predicts. The influence of spin alignment on particle energy spectra is discussed shortly. (orig.)

  6. International emissions trading

    DEFF Research Database (Denmark)

    Boom, Jan Tjeerd

    This thesis discusses the design and political acceptability of international emissions trading. It is shown that there are several designs options for emissions trading at the national level that have a different impact on output and thereby related factors such as employment and consumer prices....... The differences in impact of the design make that governments may prefer different designs of emissions trading in different situations. The thesis furthermore establishes that international emissions trading may lead to higher overall emissions, which may make it a less attractive instrument....

  7. Shipping emissions in ports

    OpenAIRE

    Merk, Olaf

    2014-01-01

    Shipping emissions in ports are substantial, accounting for 18 million tonnes of CO2 emissions, 0.4 million tonnes of NOx, 0.2 million of SOx and 0.03 million tonnes of PM10 in 2011. Around 85% of emissions come from containerships and tankers. Containerships have short port stays, but high emissions during these stays. Most of CO2 emissions in ports from shipping are in Asia and Europe (58%), but this share is low compared to their share of port calls (70%). European ports have much less emi...

  8. THEORETICAL EVOLUTION OF OPTICAL STRONG LINES ACROSS COSMIC TIME

    Energy Technology Data Exchange (ETDEWEB)

    Kewley, Lisa J.; Dopita, Michael A.; Sutherland, Ralph [Research School for Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611 (Australia); Leitherer, Claus [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Dave, Romeel [Department of Astronomy/Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Yuan, Tiantian [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Allen, Mark [Observatoire de Strasbourg, UMR 7550, Strasbourg 67000 (France); Groves, Brent, E-mail: kewley@mso.anu.edu.au [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)

    2013-09-10

    We use the chemical evolution predictions of cosmological hydrodynamic simulations with our latest theoretical stellar population synthesis, photoionization, and shock models to predict the strong line evolution of ensembles of galaxies from z = 3 to the present day. In this paper, we focus on the brightest optical emission-line ratios, [N II]/H{alpha} and [O III]/H{beta}. We use the optical diagnostic Baldwin-Phillips-Terlevich (BPT) diagram as a tool for investigating the spectral properties of ensembles of active galaxies. We use four redshift windows chosen to exploit new near-infrared multi-object spectrographs. We predict how the BPT diagram will appear in these four redshift windows given different sets of assumptions. We show that the position of star-forming galaxies on the BPT diagram traces the interstellar medium conditions and radiation field in galaxies at a given redshift. Galaxies containing active galactic nucleus (AGN) form a mixing sequence with purely star-forming galaxies. This mixing sequence may change dramatically with cosmic time, due to the metallicity sensitivity of the optical emission-lines. Furthermore, the position of the mixing sequence may probe metallicity gradients in galaxies as a function of redshift, depending on the size of the AGN narrow-line region. We apply our latest slow shock models for gas shocked by galactic-scale winds. We show that at high redshift, galactic wind shocks are clearly separated from AGN in line ratio space. Instead, shocks from galactic winds mimic high metallicity starburst galaxies. We discuss our models in the context of future large near-infrared spectroscopic surveys.

  9. Renormalization in theories with strong vector forces

    International Nuclear Information System (INIS)

    Kocic, A.

    1991-01-01

    There are not many field theories in four dimensions that have sensible ultraviolet and interesting (non-trivial) infrared behavior. At present, asymptotically free theories seem to have deserved their legitimacy and there is a strong prejudice that they might be the only ones to have such a distinction. This belief stems mostly from the fact that most of the knowledge of field theory in four dimensions comes from perturbation theory. However, nonperturbative studies of the lower dimensional theories reveal a host of interesting phenomena that are perturbative studies of the lower dimensional theories reveal a host of interesting phenomena that perturbatively inaccessible. The lack of asymptotic freedom implies that the coupling constant grows at short distances and perturbation theory breaks down. Thus, in such theories, ultraviolet behavior requires nonperturbative treatment. Recently, the interest in strongly coupled gauge theories has been revived. In particularly, four dimensional quantum electrodynamics has received considerable attention. This was motivated by the discovery of an ultraviolet stable fixed point at strong couplings. If this fixed point would turn out to be non-gaussian, then QED would be the first nontrivial nonasymptotically free theory in four dimensions. The importance of such a result would be twofold. First, the old question of the existence of QED could be settled. Of course, this would be the case provided that the low energy limit of the theory actually describes photons and electrons; apriori, there is no reason to assume this. Second, the discovery of a nontrivial nonasymptotically free theory would be of great paradigmatic value. The theories which quenched QED resembles the most are nonabelian gauge theories with many flavors with beta-function positive or vanishing at weak couplings. These theories are at present considered as viable candidates for technicolor unification schemes

  10. Gold emissivities for hydrocode applications

    Science.gov (United States)

    Bowen, C.; Wagon, F.; Galmiche, D.; Loiseau, P.; Dattolo, E.; Babonneau, D.

    2004-10-01

    The Radiom model [M. Busquet, Phys Fluids B 5, 4191 (1993)] is designed to provide a radiative-hydrodynamic code with non-local thermodynamic equilibrium (non-LTE) data efficiently by using LTE tables. Comparison with benchmark data [M. Klapisch and A. Bar-Shalom, J. Quant. Spectrosc. Radiat. Transf. 58, 687 (1997)] has shown Radiom to be inaccurate far from LTE and for heavy ions. In particular, the emissivity was found to be strongly underestimated. A recent algorithm, Gondor [C. Bowen and P. Kaiser, J. Quant. Spectrosc. Radiat. Transf. 81, 85 (2003)], was introduced to improve the gold non-LTE ionization and corresponding opacity. It relies on fitting the collisional ionization rate to reproduce benchmark data given by the Averroès superconfiguration code [O. Peyrusse, J. Phys. B 33, 4303 (2000)]. Gondor is extended here to gold emissivity calculations, with two simple modifications of the two-level atom line source function used by Radiom: (a) a larger collisional excitation rate and (b) the addition of a Planckian source term, fitted to spectrally integrated Averroès emissivity data. This approach improves the agreement between experiments and hydrodynamic simulations.

  11. Gold emissivities for hydrocode applications

    International Nuclear Information System (INIS)

    Bowen, C.; Wagon, F.; Galmiche, D.; Loiseau, P.; Dattolo, E.; Babonneau, D.

    2004-01-01

    The Radiom model [M. Busquet, Phys Fluids B 5, 4191 (1993)] is designed to provide a radiative-hydrodynamic code with non-local thermodynamic equilibrium (non-LTE) data efficiently by using LTE tables. Comparison with benchmark data [M. Klapisch and A. Bar-Shalom, J. Quant. Spectrosc. Radiat. Transf. 58, 687 (1997)] has shown Radiom to be inaccurate far from LTE and for heavy ions. In particular, the emissivity was found to be strongly underestimated. A recent algorithm, Gondor [C. Bowen and P. Kaiser, J. Quant. Spectrosc. Radiat. Transf. 81, 85 (2003)], was introduced to improve the gold non-LTE ionization and corresponding opacity. It relies on fitting the collisional ionization rate to reproduce benchmark data given by the Averroes superconfiguration code [O. Peyrusse, J. Phys. B 33, 4303 (2000)]. Gondor is extended here to gold emissivity calculations, with two simple modifications of the two-level atom line source function used by Radiom: (a) a larger collisional excitation rate and (b) the addition of a Planckian source term, fitted to spectrally integrated Averroes emissivity data. This approach improves the agreement between experiments and hydrodynamic simulations

  12. Many Body Structure of Strongly Interacting Systems

    CERN Document Server

    Arenhövel, Hartmuth; Drechsel, Dieter; Friedrich, Jörg; Kaiser, Karl-Heinz; Walcher, Thomas; Symposium on 20 Years of Physics at the Mainz Microtron MAMI

    2006-01-01

    This carefully edited proceedings volume provides an extensive review and analysis of the work carried out over the past 20 years at the Mainz Microtron (MAMI). This research centered around the application of Quantum Chromodynamics in the strictly nonperturbative regime at hadronic scales of about 1 fm. Due to the many degrees of freedom in hadrons at this scale the leitmotiv of this research is "Many body structure of strongly interacting systems". Further, an outlook on the research with the forthcoming upgrade of MAMI is given. This volume is an authoritative source of reference for everyone interested in the field of the electro-weak probing of the structure of hadrons.

  13. The Dark Side of Strongly Coupled Theories

    DEFF Research Database (Denmark)

    Kouvaris, Christoforos

    2008-01-01

    We investigate the constraints of dark matter search experiments on the different candidates emerging from the minimal quasi-conformal strong coupling theory with fermions in the adjoint representation. For one candidate, the current limits of CDMS exclude a tiny window of masses around 120 GeV. We...... also investigate under what circumstances the newly proposed candidate composed of a -2 negatively charged particle and a $^4He^{+2}$ can explain the discrepancy between the results of the CDMS and DAMA experiments. We found that this type of dark matter should give negative results in CDMS, while...

  14. Hawking radiation and strong gravity black holes

    International Nuclear Information System (INIS)

    Qadir, A.; Sayed, W.A.

    1979-01-01

    It is shown that the strong gravity theory of Salam et al. places severe restrictions on black hole evaporation. Two major implications are that: mini blck holes (down to masses approximately 10 -16 kg) would be stable in the present epoch; and that some suggested mini black hole mechanisms to explain astrophysical phenomena would not work. The first result implies that f-gravity appears to make black holes much safer by removing the possibility of extremely violent black hole explosions suggested by Hawking. (Auth.)

  15. Strong piezoelectricity in bioinspired peptide nanotubes.

    Science.gov (United States)

    Kholkin, Andrei; Amdursky, Nadav; Bdikin, Igor; Gazit, Ehud; Rosenman, Gil

    2010-02-23

    We show anomalously strong shear piezoelectric activity in self-assembled diphenylalanine peptide nanotubes (PNTs), indicating electric polarization directed along the tube axis. Comparison with well-known piezoelectric LiNbO(3) and lateral signal calibration yields sufficiently high effective piezoelectric coefficient values of at least 60 pm/V (shear response for tubes of approximately 200 nm in diameter). PNTs demonstrate linear deformation without irreversible degradation in a broad range of driving voltages. The results open up a wide avenue for developing new generations of "green" piezoelectric materials and piezonanodevices based on bioactive tubular nanostructures potentially compatible with human tissue.

  16. Phase diagram of strongly correlated Fermi systems

    International Nuclear Information System (INIS)

    Zverev, M.V.; Khodel', V.A.; Baldo, M.

    2000-01-01

    Phase transitions in uniform Fermi systems with repulsive forces between the particles caused by restructuring of quasiparticle filling n(p) are analyzed. It is found that in terms of variables, i.e. density ρ, nondimensional binding constant η, phase diagram of a strongly correlated Fermi system for rather a wide class of interactions reminds of a puff-pastry pie. Its upper part is filled with fermion condensate, the lower one - with normal Fermi-liquid. They are separated by a narrow interlayer - the Lifshits phase, characterized by the Fermi multibound surface [ru

  17. Strong Interaction Studies with PANDA at FAIR

    Science.gov (United States)

    Schönning, Karin

    2016-10-01

    The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme.

  18. Strong Interaction Studies with PANDA at FAIR

    International Nuclear Information System (INIS)

    Schönning, Karin

    2016-01-01

    The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme

  19. Development of a strong electromagnet wiggler

    International Nuclear Information System (INIS)

    Burns, M.J.; Deis, G.A.; Holmes, R.H.; Van Maren, R.D.; Halbach, K.

    1987-01-01

    The Strong Electromagnet (SEM) wiggler is a permanent magnet-assisted electromagnet under development at the Lawrence Livermore National Laboratory (LLNL) as part of the Induction Linac Free-Electron-Laser (IFEL) program. This concept uses permanent magnets within the wiggler to provide a reverse bias flux in the iron and thus delay the onset of magnetic saturation. The electromagnet coils determine the wiggler field and operate at low current densities by virtue of their placement away from the midplane. We describe here the design approach used and test data from a 7-period wiggler prototype that includes curved pole tips to provide wiggle-plane focusing. 7 refs

  20. Calorimetric measurement of strong γ emitting sources

    International Nuclear Information System (INIS)

    Brangier, B.; Herczeg, C.; Henry, R.

    1968-01-01

    This publication gives the principle and a description of an adiabatic calorimeter for measuring the real activity of strong gamma-emitting sources by absorbing the emitted energy in a mass of copper. Because of the difficulty of evaluating the amount self- absorption, we have built a calorimeter for measuring the self- absorption, and a description of it is given.The results of these three measurements are fairly satisfactory. The calibration and the actual measurements obtained are given with a few corrections made necessary by the design of the apparatus. The correlation of the various results is discussed. (author) [fr

  1. Unification of electromagnetic, strong and weak interaction

    International Nuclear Information System (INIS)

    Duong Van Phi; Duong Anh Duc

    1993-09-01

    The Unification of Electromagnetic, Strong and Weak Interactions is realized in the framework of the Quantum Field Theory, established in an 8-dimensional Unified Space. Two fundamental, spinor and vector field equations are considered. The first of the matter particles and the second is of the gauge particles. Interaction Lagrangians are formed from the external and internal currents and the external and internal vector field operators. Generators of the local gauge transformations are the combinations of the matrices of the first field equation. (author). 15 refs

  2. Gravitational leptogenesis, C, CP and strong equivalence

    International Nuclear Information System (INIS)

    McDonald, Jamie I.; Shore, Graham M.

    2015-01-01

    The origin of matter-antimatter asymmetry is one of the most important outstanding problems at the interface of particle physics and cosmology. Gravitational leptogenesis (baryogenesis) provides a possible mechanism through explicit couplings of spacetime curvature to appropriate lepton (or baryon) currents. In this paper, the idea that these strong equivalence principle violating interactions could be generated automatically through quantum loop effects in curved spacetime is explored, focusing on the realisation of the discrete symmetries C, CP and CPT which must be broken to induce matter-antimatter asymmetry. The related issue of quantum corrections to the dispersion relation for neutrino propagation in curved spacetime is considered within a fully covariant framework.

  3. Strongly interacting Higgs sector without technicolor

    International Nuclear Information System (INIS)

    Liu Chuan; Kuti, J.

    1994-12-01

    Simulation results are presented on Higgs mass calculations in the spontaneously broken phase of the Higgs sector in the minimal Standard Model with a higher derviative regulator. A heavy Higgs particle is found in the TeV mass range in the presence of a complex conjugate ghost pair at higher energies. The ghost pair evades easy experimental detection. As a finite and unitary theory in the continuum, this model serves as an explicit and simple example of a strong interacting Higgs sector without technicolor. (orig.)

  4. Strong signatures of right-handed compositeness

    Energy Technology Data Exchange (ETDEWEB)

    Redi, Michele [INFN, Sesto Fiorentino, Firenze (Italy); Sanz, Veronica [York Univ., Toronto, ON (Canada). Dept. of Physics and Astronomy; Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy; Vries, Maikel de; Weiler, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-05-15

    Right-handed light quarks could be significantly composite, yet compatible with experimental searches at the LHC and precision tests on Standard Model couplings. In these scenarios, that are motivated by flavor physics, one expects large cross sections for the production of new resonances coupled to light quarks. We study experimental strong signatures of right-handed compositeness at the LHC, and constrain the parameter space of these models with recent results by ATLAS and CMS. We show that the LHC sensitivity could be significantly improved if dedicated searches were performed, in particular in multi-jet signals.

  5. Bright branes for strongly coupled plasmas

    International Nuclear Information System (INIS)

    Mateos, David; Patino, Leonardo

    2007-01-01

    We use holographic techniques to study photon production in a class of finite temperature, strongly coupled, large-N c SU(N c ) quark-gluon plasmas with N f c quark flavours. Our results are valid to leading order in the electromagnetic coupling constant but non-perturbatively in the SU(N c ) interactions. The spectral function of electromagnetic currents and other related observables exhibit an interesting structure as a function of the photon frequency and the quark mass. We discuss possible implications for heavy ion collision experiments

  6. Strong coupling transmutation of Yukawa theory

    International Nuclear Information System (INIS)

    Chiang, C.C.; Chiu, C.B.; Sudarshan, E.C.G.

    1981-01-01

    In the strong coupling limit, it is shown that the Yukawa-type theory can be made to undergo a transmutation into an attractive separable potential theory, provided a single state is removed from the spectrum in the lowest nontrivial sector and the states at infinity which include a continuum in the next sector. If these states are not removed, the two theories are distinct. It is suggested that the full equivalence and the renormalization of four-fermion theories need further examination. (orig.)

  7. Categorization of States Beyond Strong and Weak

    Directory of Open Access Journals (Sweden)

    Peter Tikuisis

    2017-09-01

    Full Text Available The discourse on poor state performers has suffered from widely varying definitions on what distinguishes certain weak states from others. Indices that rank states from strong to weak conceal important distinctions that can adversely affect intervention policy. This deficiency is addressed by grouping states according to their performance on three dimensions of statehood: authority, legitimacy, and capacity. The resultant categorization identifies brittle states that are susceptible to regime change, impoverished states often considered as aid darlings, and fragile states that experience disproportionately high levels of violent internal conflict. It also provides a quantifiable means to analyze transitions from one state type to another for more insightful intervention policy.

  8. Strong Interactions Physics at BaBar

    Energy Technology Data Exchange (ETDEWEB)

    Pioppi, M.

    2005-03-14

    Recent results obtained by BABAR experiment and related to strong interactions physics are presented, with particular attention to the extraction of the first four hadronic-mass moments and the first three lepton-energy moments in semileptonic decays. From a simultaneous fit to the moments, the CKM element |V{sub cb}|, the inclusive B {yields} X{sub c}lv and other heavy quark parameters are derived. The second topic is the ambiguity-free measurement of cos(2{beta}) in B {yields} J/{Psi}K* decays. With approximately 88 million of B{bar B} pairs, negative solutions for cos(2{beta}) are excluded at 89%.

  9. Gravitational leptogenesis, C, CP and strong equivalence

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Jamie I.; Shore, Graham M. [Department of Physics, Swansea University,Swansea, SA2 8PP (United Kingdom)

    2015-02-12

    The origin of matter-antimatter asymmetry is one of the most important outstanding problems at the interface of particle physics and cosmology. Gravitational leptogenesis (baryogenesis) provides a possible mechanism through explicit couplings of spacetime curvature to appropriate lepton (or baryon) currents. In this paper, the idea that these strong equivalence principle violating interactions could be generated automatically through quantum loop effects in curved spacetime is explored, focusing on the realisation of the discrete symmetries C, CP and CPT which must be broken to induce matter-antimatter asymmetry. The related issue of quantum corrections to the dispersion relation for neutrino propagation in curved spacetime is considered within a fully covariant framework.

  10. Air Emissions Factors and Quantification

    Science.gov (United States)

    Emissions factors are used in developing air emissions inventories for air quality management decisions and in developing emissions control strategies. This area provides technical information on and support for the use of emissions factors.

  11. General-relativistic pulsar magnetospheric emission

    Science.gov (United States)

    Pétri, J.

    2018-06-01

    Most current pulsar emission models assume photon production and emission within the magnetosphere. Low-frequency radiation is preferentially produced in the vicinity of the polar caps, whereas the high-energy tail is shifted to regions closer but still inside the light cylinder. We conducted a systematic study of the merit of several popular radiation sites like the polar cap, the outer gap, and the slot gap. We computed sky maps emanating from each emission site according to a prescribed distribution function for the emitting particles made of an electron/positron mixture. Calculations are performed using a three-dimensional integration of the plasma emissivity in the vacuum electromagnetic field of a rotating and centred general-relativistic dipole. We compare Newtonian electromagnetic fields to their general-relativistic counterpart. In the latter case, light bending is also taken into account. As a typical example, light curves and sky maps are plotted for several power-law indices of the particle distribution function. The detailed pulse profiles strongly depend on the underlying assumption about the fluid motion subject to strong electromagnetic fields. This electromagnetic topology enforces the photon propagation direction directly, or indirectly, from aberration effects. We also discuss the implication of a net stellar electric charge on to sky maps. Taking into account, the electric field strongly affects the light curves originating close to the light cylinder, where the electric field strength becomes comparable to the magnetic field strength.

  12. Iterative solutions of nonlinear equations with strongly accretive or strongly pseudocontractive maps

    International Nuclear Information System (INIS)

    Chidume, C.E.

    1994-03-01

    Let E be a real q-uniformly smooth Banach space. Suppose T is a strongly pseudo-contractive map with open domain D(T) in E. Suppose further that T has a fixed point in D(T). Under various continuity assumptions on T it is proved that each of the Mann iteration process or the Ishikawa iteration method converges strongly to the unique fixed point of T. Related results deal with iterative solutions of nonlinear operator equations involving strongly accretive maps. Explicit error estimates are also provided. (author). 38 refs

  13. A strongly interacting polaritonic quantum dot

    Science.gov (United States)

    Jia, Ningyuan; Schine, Nathan; Georgakopoulos, Alexandros; Ryou, Albert; Clark, Logan W.; Sommer, Ariel; Simon, Jonathan

    2018-06-01

    Polaritons are promising constituents of both synthetic quantum matter1 and quantum information processors2, whose properties emerge from their components: from light, polaritons draw fast dynamics and ease of transport; from matter, they inherit the ability to collide with one another. Cavity polaritons are particularly promising as they may be confined and subjected to synthetic magnetic fields controlled by cavity geometry3, and furthermore they benefit from increased robustness due to the cavity enhancement in light-matter coupling. Nonetheless, until now, cavity polaritons have operated only in a weakly interacting mean-field regime4,5. Here we demonstrate strong interactions between individual cavity polaritons enabled by employing highly excited Rydberg atoms as the matter component of the polaritons. We assemble a quantum dot composed of approximately 150 strongly interacting Rydberg-dressed 87Rb atoms in a cavity, and observe blockaded transport of photons through it. We further observe coherent photon tunnelling oscillations, demonstrating that the dot is zero-dimensional. This work establishes the cavity Rydberg polariton as a candidate qubit in a photonic information processor and, by employing multiple resonator modes as the spatial degrees of freedom of a photonic particle, the primary ingredient to form photonic quantum matter6.

  14. Between strong continuity and almost continuity

    Directory of Open Access Journals (Sweden)

    J.K. Kohli

    2010-04-01

    Full Text Available As embodied in the title of the paper strong and weak variants of continuity that lie strictly between strong continuity of Levine and almost continuity due to Singal and Singal are considered. Basic properties of almost completely continuous functions (≡ R-maps and δ-continuous functions are studied. Direct and inverse transfer of topological properties under almost completely continuous functions and δ-continuous functions are investigated and their place in the hier- archy of variants of continuity that already exist in the literature is out- lined. The class of almost completely continuous functions lies strictly between the class of completely continuous functions studied by Arya and Gupta (Kyungpook Math. J. 14 (1974, 131-143 and δ-continuous functions defined by Noiri (J. Korean Math. Soc. 16, (1980, 161-166. The class of almost completely continuous functions properly contains each of the classes of (1 completely continuous functions, and (2 al- most perfectly continuous (≡ regular set connected functions defined by Dontchev, Ganster and Reilly (Indian J. Math. 41 (1999, 139-146 and further studied by Singh (Quaestiones Mathematicae 33(2(2010, 1–11 which in turn include all δ-perfectly continuous functions initi- ated by Kohli and Singh (Demonstratio Math. 42(1, (2009, 221-231 and so include all perfectly continuous functions introduced by Noiri (Indian J. Pure Appl. Math. 15(3 (1984, 241-250.

  15. Caviton dynamics in strong Langmuir turbulence

    Science.gov (United States)

    DuBois, Don; Rose, Harvey A.; Russell, David

    1990-01-01

    Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound damping the turbulent energy is dominantly in non-linear "caviton" excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation-collapse-burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful HF waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that "free" Langmuir waves are emitted in the caviton collapse process. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed.

  16. Caviton dynamics in strong Langmuir turbulence

    International Nuclear Information System (INIS)

    DuBois, D.; Rose, H.A.; Russell, D.

    1990-01-01

    Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound damping the turbulent energy is dominantly in non-linear ''caviton'' excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation-collapse-burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful HF waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that ''free'' Langmuir waves are emitted in the caviton collapse process. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed. (orig.)

  17. Fractional Transport in Strongly Turbulent Plasmas

    Science.gov (United States)

    Isliker, Heinz; Vlahos, Loukas; Constantinescu, Dana

    2017-07-01

    We analyze statistically the energization of particles in a large scale environment of strong turbulence that is fragmented into a large number of distributed current filaments. The turbulent environment is generated through strongly perturbed, 3D, resistive magnetohydrodynamics simulations, and it emerges naturally from the nonlinear evolution, without a specific reconnection geometry being set up. Based on test-particle simulations, we estimate the transport coefficients in energy space for use in the classical Fokker-Planck (FP) equation, and we show that the latter fails to reproduce the simulation results. The reason is that transport in energy space is highly anomalous (strange), the particles perform Levy flights, and the energy distributions show extended power-law tails. Newly then, we motivate the use and derive the specific form of a fractional transport equation (FTE), we determine its parameters and the order of the fractional derivatives from the simulation data, and we show that the FTE is able to reproduce the high energy part of the simulation data very well. The procedure for determining the FTE parameters also makes clear that it is the analysis of the simulation data that allows us to make the decision whether a classical FP equation or a FTE is appropriate.

  18. Caviton dynamics in strong Langmuir turbulence

    International Nuclear Information System (INIS)

    DuBois, D.; Rose, H.A.; Russell, D.

    1989-01-01

    Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound samping the turbulent energy is dominantly in nonlinear ''caviton'' excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation-collapse-burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful hf waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that ''free'' Langmuir waves are emitted in the caviton collapse process. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed. 40 refs., 19 figs

  19. Hypernuclear matter in strong magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Monika [Institute for Theoretical Physics, J.W. Goethe-University, D-60438 Frankfurt am Main (Germany); Indian Institute of Technology Rajasthan, Old Residency Road, Ratanada, Jodhpur 342011 (India); Mukhopadhyay, Banibrata [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Sedrakian, Armen, E-mail: sedrakian@th.physik.uni-frankfurt.de [Institute for Theoretical Physics, J.W. Goethe-University, D-60438 Frankfurt am Main (Germany)

    2013-01-17

    Compact stars with strong magnetic fields (magnetars) have been observationally determined to have surface magnetic fields of order of 10{sup 14}–10{sup 15} G, the implied internal field strength being several orders larger. We study the equation of state and composition of dense hypernuclear matter in strong magnetic fields in a range expected in the interiors of magnetars. Within the non-linear Boguta–Bodmer–Walecka model we find that the magnetic field has sizable influence on the properties of matter for central magnetic field B⩾10{sup 17} G, in particular the matter properties become anisotropic. Moreover, for the central fields B⩾10{sup 18} G, the magnetized hypernuclear matter shows instability, which is signalled by the negative sign of the derivative of the pressure parallel to the field with respect to the density, and leads to vanishing parallel pressure at the critical value B{sub cr}≃10{sup 19} G. This limits the range of admissible homogeneously distributed fields in magnetars to fields below the critical value B{sub cr}.

  20. Radiative properties of strongly magnetized plasmas

    International Nuclear Information System (INIS)

    Weisheit, J.C.

    1993-11-01

    The influence of strong magnetic fields on quantum phenomena continues to be a topic of much interest to physicists and astronomers investigating a wide array of problems - the formation of high energy-density plasmas in pulsed power experiments, the crustal structure and radiative properties of neutron stars, transport coefficients of matter irradiated by subpicosecond lasers, the spectroscopy of magnetic white dwarf stars, the quantum Hall effect, etc. The passage of time finds more questions being asked than being answered in this subject, where even the hydrogen atom open-quotes paradigmclose quotes remains a major challenge. This theoretical program consists of two distinct parts: (1) investigation into the structure and transport properties of many-electron atoms in fields B > 10 8 Gauss; and (2) extension of spectral lineshape methods for diagnosing fields in strongly magnetized plasmas. Research during the past year continued to be focused on the first topic, primarily because of the interest and skills of Dr. E.P. Lief, the postdoctoral research associate who was hired to work on the proposal

  1. Strong correlations in few-fermion systems

    Energy Technology Data Exchange (ETDEWEB)

    Bergschneider, Andrea

    2017-07-26

    In this thesis, I report on the deterministic preparation and the observation of strongly correlated few-fermion systems in single and double-well potentials. In a first experiment, we studied a system of one impurity interacting with a number of majority atoms which we prepared in a single potential well in the one-dimensional limit. With increasing number of majority particles, we observed a decrease in the quasi-particle residue which is in agreement with expectations from the Anderson orthogonality catastrophe. In a second experiment, we prepared two fermions in a double-well potential which represents the fundamental building block of the Fermi-Hubbard model. By increasing the repulsion between the two fermions, we observed the crossover into the antiferromagnetic Mott-insulator regime. Furthermore, I describe a new imaging technique, which allows spin-resolved single-atom detection both in in-situ and in time-of-flight. We use this technique to investigate the emergence of momentum correlations of two repulsive fermions in the ground state of the double well. With the methods developed in this thesis, we have established a framework for quantum simulation of strongly correlated many-body systems in tunable potentials.

  2. Can strong gravitational lensing constrain dark energy?

    International Nuclear Information System (INIS)

    Lee, Seokcheon; Ng, K.-W.

    2007-01-01

    We discuss the ratio of the angular diameter distances from the source to the lens, D ds , and to the observer at present, D s , for various dark energy models. It is well known that the difference of D s s between the models is apparent and this quantity is used for the analysis of Type Ia supernovae. However we investigate the difference between the ratio of the angular diameter distances for a cosmological constant, (D ds /D s ) Λ , and that for other dark energy models, (D ds /D s ) other , in this paper. It has been known that there is lens model degeneracy in using strong gravitational lensing. Thus, we investigate the model independent observable quantity, Einstein radius (θ E ), which is proportional to both D ds /D s and velocity dispersion squared, σ v 2 . D ds /D s values depend on the parameters of each dark energy model individually. However, (D ds /D s ) Λ -(D ds /D s ) other for the various dark energy models, is well within the error of σ v for most of the parameter spaces of the dark energy models. Thus, a single strong gravitational lensing by use of the Einstein radius may not be a proper method to investigate the property of dark energy. However, better understanding to the mass profile of clusters in the future or other methods related to arc statistics rather than the distances may be used for constraints on dark energy

  3. Towards TDDFT for Strongly Correlated Materials

    Directory of Open Access Journals (Sweden)

    Shree Ram Acharya

    2016-09-01

    Full Text Available We present some details of our recently-proposed Time-Dependent Density-Functional Theory (TDDFT for strongly-correlated materials in which the exchange-correlation (XC kernel is derived from the charge susceptibility obtained using Dynamical Mean-Field Theory (the TDDFT + DMFT approach. We proceed with deriving the expression for the XC kernel for the one-band Hubbard model by solving DMFT equations via two approaches, the Hirsch–Fye Quantum Monte Carlo (HF-QMC and an approximate low-cost perturbation theory approach, and demonstrate that the latter gives results that are comparable to the exact HF-QMC solution. Furthermore, through a variety of applications, we propose a simple analytical formula for the XC kernel. Additionally, we use the exact and approximate kernels to examine the nonhomogeneous ultrafast response of two systems: a one-band Hubbard model and a Mott insulator YTiO3. We show that the frequency dependence of the kernel, i.e., memory effects, is important for dynamics at the femtosecond timescale. We also conclude that strong correlations lead to the presence of beats in the time-dependent electric conductivity in YTiO3, a feature that could be tested experimentally and that could help validate the few approximations used in our formulation. We conclude by proposing an algorithm for the generalization of the theory to non-linear response.

  4. Holographic gauge mediation via strongly coupled messengers

    International Nuclear Information System (INIS)

    McGuirk, Paul; Shiu, Gary; Sumitomo, Yoske

    2010-01-01

    We consider a relative of semidirect gauge mediation where the hidden sector exists at large 't Hooft coupling. Such scenarios can be difficult to describe using perturbative field theory methods but may fall into the class of holographic gauge mediation scenarios, meaning that they are amenable to the techniques of gauge/gravity duality. We use a recently found gravity solution to examine one such case, where the hidden sector is a cascading gauge theory resulting in a confinement scale not much smaller than the messenger mass. In the original construction of holographic gauge mediation, as in other examples of semidirect gauge mediation at strong coupling, the primary contributions to visible sector soft terms come from weakly coupled messenger mesons. In contrast to these examples, we describe the dual of a gauge theory where there are significant contributions from scales in which the strongly coupled messenger quarks are the effective degrees of freedom. In this regime, the visible sector gaugino mass can be calculated entirely from holography.

  5. Finite temperature system of strongly interacting baryons

    International Nuclear Information System (INIS)

    Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.

    1976-07-01

    A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc 2 /k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10 11 0 K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light

  6. Strong eukaryotic IRESs have weak secondary structure.

    Directory of Open Access Journals (Sweden)

    Xuhua Xia

    Full Text Available BACKGROUND: The objective of this work was to investigate the hypothesis that eukaryotic Internal Ribosome Entry Sites (IRES lack secondary structure and to examine the generality of the hypothesis. METHODOLOGY/PRINCIPAL FINDINGS: IRESs of the yeast and the fruit fly are located in the 5'UTR immediately upstream of the initiation codon. The minimum folding energy (MFE of 60 nt RNA segments immediately upstream of the initiation codons was calculated as a proxy of secondary structure stability. MFE of the reverse complements of these 60 nt segments was also calculated. The relationship between MFE and empirically determined IRES activity was investigated to test the hypothesis that strong IRES activity is associated with weak secondary structure. We show that IRES activity in the yeast and the fruit fly correlates strongly with the structural stability, with highest IRES activity found in RNA segments that exhibit the weakest secondary structure. CONCLUSIONS: We found that a subset of eukaryotic IRESs exhibits very low secondary structure in the 5'-UTR sequences immediately upstream of the initiation codon. The consistency in results between the yeast and the fruit fly suggests a possible shared mechanism of cap-independent translation initiation that relies on an unstructured RNA segment.

  7. Qubit absorption refrigerator at strong coupling

    Science.gov (United States)

    Mu, Anqi; Agarwalla, Bijay Kumar; Schaller, Gernot; Segal, Dvira

    2017-12-01

    We demonstrate that a quantum absorption refrigerator (QAR) can be realized from the smallest quantum system, a qubit, by coupling it in a non-additive (strong) manner to three heat baths. This function is un-attainable for the qubit model under the weak system-bath coupling limit, when the dissipation is additive. In an optimal design, the reservoirs are engineered and characterized by a single frequency component. We then obtain closed expressions for the cooling window and refrigeration efficiency, as well as bounds for the maximal cooling efficiency and the efficiency at maximal power. Our results agree with macroscopic designs and with three-level models for QARs, which are based on the weak system-bath coupling assumption. Beyond the optimal limit, we show with analytical calculations and numerical simulations that the cooling efficiency varies in a non-universal manner with model parameters. Our work demonstrates that strongly-coupled quantum machines can exhibit function that is un-attainable under the weak system-bath coupling assumption.

  8. Finite temperature system of strongly interacting baryons

    Energy Technology Data Exchange (ETDEWEB)

    Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.

    1976-07-01

    A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc/sup 2//k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10/sup 11/ /sup 0/K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light.

  9. Strongly coupled models at the LHC

    International Nuclear Information System (INIS)

    Vries, Maikel de

    2014-10-01

    In this thesis strongly coupled models where the Higgs boson is composite are discussed. These models provide an explanation for the origin of electroweak symmetry breaking including a solution for the hierarchy problem. Strongly coupled models provide an alternative to the weakly coupled supersymmetric extensions of the Standard Model and lead to different and interesting phenomenology at the Large Hadron Collider (LHC). This thesis discusses two particular strongly coupled models, a composite Higgs model with partial compositeness and the Littlest Higgs model with T-parity - a composite model with collective symmetry breaking. The phenomenology relevant for the LHC is covered and the applicability of effective operators for these types of strongly coupled models is explored. First, a composite Higgs model with partial compositeness is discussed. In this model right-handed light quarks could be significantly composite, yet compatible with experimental searches at the LHC and precision tests on Standard Model couplings. In these scenarios, which are motivated by flavour physics, large cross sections for the production of new resonances coupling to light quarks are expected. Experimental signatures of right-handed compositeness at the LHC are studied, and constraints on the parameter space of these models are derived using recent results by ATLAS and CMS. Furthermore, dedicated searches for multi-jet signals at the LHC are proposed which could significantly improve the sensitivity to signatures of right-handed compositeness. The Littlest Higgs model with T-parity, providing an attractive solution to the fine-tuning problem, is discussed next. This solution is only natural if its intrinsic symmetry breaking scale f is relatively close to the electroweak scale. The constraints from the latest results of the 8 TeV run at the LHC are examined. The model's parameter space is being excluded based on a combination of electroweak precision observables, Higgs precision

  10. White top emitting OLED with angle independent emission characteristic

    Energy Technology Data Exchange (ETDEWEB)

    Thomschke, Michael; Freitag, Patricia; Schwartz, Gregor; Nitsche, Robert; Walzer, Karsten; Leo, Karl [Technische Universitaet Dresden, Institut fuer Angewandte Photophysik, Georg-Baehr-Strasse 1, 01062 Dresden (Germany)

    2008-07-01

    The general device structure of a top emitting organic light emitting diode (OLED) consists of several organic layers sandwiched in between two metal contacts, with the top one being semitransparent for light outcoupling reasons. Due to the high reflectivity of the electrodes, strong microcavity effects occur which lead to a preferred emission of light of a certain wavelength with main outcoupling in forward direction. This creates rather narrow emission bands, accompanied by strong spectral shifts upon viewing angle variation. By using an organic capping layer on top of the semitransparent metal contact, this unwanted effect can be reduced. This is important especially for white light emission for the use of OLEDs in future lighting applications. Our optical simulations show that the strong angular dependence of the emission color almost vanishes. To verify the simulations we study white top emitting OLEDs based on an approach which are adapted to the top emitting case.

  11. Reference Projections Energy and Emissions 2005-2020

    International Nuclear Information System (INIS)

    Van Dril, A.W.N.; Elzenga, H.E.

    2005-10-01

    The Reference Projection 2005-2020 covers the future development of Dutch energy use, greenhouse gas emissions and air pollution up to 2020. The Reference projection is based on assumptions regarding economic, structural, technological and policy developments. Two scenarios have been used. The Strong Europe (SE) scenario is characterized by moderate economic growth and strong public responsibility. The Global Economy (GE) scenario assumes high economic growth and has a strong orientation towards private responsibility. Energy consumption continues to grow in both scenarios and energy intensity is declining in the GE-scenario. Gradual rise of temperature is now included in the estimates for space heating and air conditioning. Energy prices for end users will rise, due to increased imports of natural gas and rising costs of electricity generation. The share of renewables in electricity consumption increases considerably due to subsidies for wind at sea and biomass, up to the target of 9% in 2010. Emissions of non-CO2 greenhouse gases are reduced and stabilise after 2010. The Dutch Kyoto target is probably met in both scenarios, assuming considerable emission reduction ef-forts abroad. Acidifying emissions of NOx and SO2 stabilise after reductions, but at levels that exceed their national emission ceiling (NEC). Emissions of volatile organic compounds are projected to fall with approximately 25% between 2002 and 2010 below their NEC. Emissions of ammonia are projected to meet their NEC. The emission of particulate matter (PM10) will stabilise at present levels

  12. Reference outlook for energy and emissions 2005-2020

    International Nuclear Information System (INIS)

    Van Dril, A.W.N.; Elzenga, H.E.

    2005-05-01

    The Reference Projection 2005-2020 covers the future development of Dutch energy use, greenhouse gas emissions and air pollution up to 2020. The Reference projection is based on assumptions regarding economic, structural, technological and policy developments. Two scenarios have been used. The Strong Europe (SE) scenario is characterized by moderate economic growth and strong public responsibility. The Global Economy (GE) scenario assumes high economic growth and has a strong orientation towards private responsibility. Energy consumption continues to grow in both scenarios and energy intensity is declining in the GE-scenario. Gradual rise of temperature is now included in the estimates for space heating and air conditioning. Energy prices for end users will rise, due to increased imports of natural gas and rising costs of electricity generation. The share of renewables in electricity consumption increases considerably due to subsidies for wind at sea and biomass, up to the target of 9% in 2010. Emissions of non-CO2 greenhouse gases are reduced and stabilise after 2010. The Dutch Kyoto target is probably met in both scenarios, assuming considerable emission reduction efforts abroad. Acidifying emissions of NOx and SO2 stabilise after reductions, but at levels that exceed their national emission ceiling (NEC). Emissions of volatile organic compounds are projected to fall with approximately 25% between 2002 and 2010 below their NEC. Emissions of ammonia are projected to meet their NEC. The emission of fine particles (PM10) will stabilise at present levels [nl

  13. The liability rules under international GHG emissions trading

    International Nuclear Information System (INIS)

    Zhong Xiang Zhang

    2001-01-01

    Article 17 of the Kyoto Protocol authorizes emissions trading, but the rules governing emissions trading have been deferred to subsequent conferences. In designing and implementing an international greenhouse gas (GHG) emissions trading scheme, assigning liability rules has been considered to be one of the most challenging issues. In general, a seller-beware liability works well in a strong enforcement environment. In the Kyoto Protocol, however, it may not always work. By contrast, a buyer-beware liability could be an effective deterrent to non-compliance, but the costs of imposing it are expected to be very high. To strike a middle ground, we suggest a combination of preventive measures with strong but feasible end-of-period punishments to ensure compliance with the Kyoto emissions commitments. Such measures aim to maximize efficiency gains from emissions trading and at the same time, to minimize over-selling risks. (author)

  14. Climate Impacts From a Removal of Anthropogenic Aerosol Emissions

    Science.gov (United States)

    Samset, B. H.; Sand, M.; Smith, C. J.; Bauer, S. E.; Forster, P. M.; Fuglestvedt, J. S.; Osprey, S.; Schleussner, C.-F.

    2018-01-01

    Limiting global warming to 1.5 or 2.0°C requires strong mitigation of anthropogenic greenhouse gas (GHG) emissions. Concurrently, emissions of anthropogenic aerosols will decline, due to coemission with GHG, and measures to improve air quality. However, the combined climate effect of GHG and aerosol emissions over the industrial era is poorly constrained. Here we show the climate impacts from removing present-day anthropogenic aerosol emissions and compare them to the impacts from moderate GHG-dominated global warming. Removing aerosols induces a global mean surface heating of 0.5-1.1°C, and precipitation increase of 2.0-4.6%. Extreme weather indices also increase. We find a higher sensitivity of extreme events to aerosol reductions, per degree of surface warming, in particular over the major aerosol emission regions. Under near-term warming, we find that regional climate change will depend strongly on the balance between aerosol and GHG forcing.

  15. SEMS operating as a proven system for screening real-world NOx and NH3 emissions

    NARCIS (Netherlands)

    Vermeulen, R.J.; Goethem, S. van; Baarbe, H.L.; Zuidgeest, L.W.M.; Spreen, J.S.; Vonk, W.A.

    2014-01-01

    NOx emissions of heavy-duty and light-duty diesel vehicles depend strongly on the driving conditions. The introduction of combined emission reduction technologies in Euro VI vehicles have demonstrated that NOx emissions become less predictable when the data is based on relatively short test cycles.

  16. Measurement of light emission in scintillation vials

    International Nuclear Information System (INIS)

    Duran Ramiro, M. Teresa; Garcia-Torano, Eduardo

    2005-01-01

    The efficiency and energy resolution of liquid scintillation counting (LSC) systems are strongly dependent on the optical characteristics of scintillators, vials, and reflectors. This article presents the results of measurements of the light-emission profile of scintillation vials. Two measurement techniques, autoradiographs and direct measurements with a photomultiplier tube, have been used to obtain light-emission distribution for standard vials of glass, etched glass and polyethylene. Results obtained with both techniques are in good agreement. For the first time, the effect of the meniscus in terms of light contribution has been numerically estimated. These results can help design LSC systems that are more efficient in terms of light collection

  17. Strongly Correlated Electron Systems: An Operatorial Perspective

    Science.gov (United States)

    Di Ciolo, Andrea; Avella, Adolfo

    2018-05-01

    We discuss the operatorial approach to the study of strongly correlated electron systems and show how the exact solution of target models on small clusters chosen ad-hoc (minimal models) can suggest very efficient bulk approximations. We use the Hubbard model as case study (target model) and we analyze and discuss the crucial role of spin fluctuations in its 2-site realization (minimal model). Accordingly, we devise a novel three-pole approximation for the 2D case, including in the basic field an operator describing the dressing of the electronic one by the nearest-neighbor spin-fluctuations. Such a solution is in very good agreement with the exact one in the minimal model (2-site case) and performs very well once compared to advanced (semi-)numerical methods in the 2D case, being by far less computational-resource demanding.

  18. Characterization of strong (241)Am sources.

    Science.gov (United States)

    Vesterlund, Anna; Chernikova, Dina; Cartemo, Petty; Axell, Kåre; Nordlund, Anders; Skarnemark, Gunnar; Ekberg, Christian; Ramebäck, Henrik

    2015-05-01

    Gamma ray spectra of strong (241)Am sources may reveal information about the source composition as there may be other radioactive nuclides such as progeny and radioactive impurities present. In this work the possibility to use gamma spectrometry to identify inherent signatures in (241)Am sources in order to differentiate sources from each other, is investigated. The studied signatures are age, i.e. time passed since last chemical separation, and presence of impurities. The spectra of some sources show a number of Doppler broadened peaks in the spectrum which indicate the presence of nuclear reactions on light elements within the sources. The results show that the investigated sources can be differentiated between by age and/or presence of impurities. These spectral features would be useful information in a national nuclear forensics library (NNFL) in cases when the visual information on the source, e.g. the source number, is unavailable. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Strongly coupled band in 140Gd

    International Nuclear Information System (INIS)

    Falla-Sotelo, F.; Oliveira, J.R.B.; Rao, M.N.

    2005-01-01

    Several high-K states are known to exist in the mass 130-140 region. For the N=74 even-even isotopes, Kπ = 8 - isomers, with lifetimes ranging from ns to ms, are known in 128 Xe, 130 Ba, 132 Ce, 134 Nd, 136 Sm, and 138 Gd[. In 140 Gd, we have observed for the first time a band also based on an Iπ = 8 - state. This could be the first case of a Kπ = 8 - state observed in an N=76 even-even isotope. The systematics of the Kπ = 8 - isomeric states in N=74 isotopes has been studied by A.M. Bruce et al. These states decay towards the K = 0 ground state band, and the transitions are K-forbidden. The 140 Gd case presents strong similarities but also some significant differences with relation to the N=74 isotopes. We propose the same configuration but with larger deformation in 140 Gd

  20. Diffraction scattering of strongly bound system

    International Nuclear Information System (INIS)

    Kuzmichev, V.E.

    1982-04-01

    The scattering of a hadron on a strongly bound system of two hadrons (dihadron) is considered in the high-energy limit for the relative hadron-dihadron motion. The dihadron scatterer motion and the internal interaction are included in our consideration. It is shown that only small values of the internal transfer momentum of dihadron particles bring the principal contribution to the three-particle propagator in eikonal approximation. On the basis of the exact analytical solution of the integral equation for the total Green function the scattering amplitude is derived. It is shown that the scattering amplitude contains only single, double, and triple scattering terms. The three new terms to the Glauber formula for the total cross section are obtained. These terms decrease both the true total hadron-hadron cross section and the screening correction. (orig.)

  1. Strong Interactions, (De)coherence and Quarkonia

    CERN Document Server

    Bellucci, Stefano; Tiwari, Bhupendra Nath

    2011-01-01

    Quarkonia are the central objects to explore the non-perturbative nature of non-abelian gauge theories. We describe the confinement-deconfinement phases for heavy quarkonia in a hot QCD medium and thereby the statistical nature of the inter-quark forces. In the sense of one-loop quantum effects, we propose that the "quantum" nature of quark matters follows directly from the thermodynamic consideration of Richardson potential. Thereby we gain an understanding of the formation of hot and dense states of quark gluon plasma matter in heavy ion collisions and the early universe. In the case of the non-abelian theory, the consideration of the Sudhakov form factor turns out to be an efficient tool for soft gluons. In the limit of the Block-Nordsieck resummation, the strong coupling obtained from the Sudhakov form factor yields the statistical nature of hadronic bound states, e.g. kaons and Ds particles.

  2. Circuit electromechanics with single photon strong coupling

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Zheng-Yuan, E-mail: zyxue@scnu.edu.cn; Yang, Li-Na [Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, and School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Zhou, Jian, E-mail: jianzhou8627@163.com [Department of Electronic Communication Engineering, Anhui Xinhua University, Hefei 230088 (China); Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, and School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China)

    2015-07-13

    In circuit electromechanics, the coupling strength is usually very small. Here, replacing the capacitor in circuit electromechanics by a superconducting flux qubit, we show that the coupling among the qubit and the two resonators can induce effective electromechanical coupling which can attain the strong coupling regime at the single photon level with feasible experimental parameters. We use dispersive couplings among two resonators and the qubit while the qubit is also driven by an external classical field. These couplings form a three-wave mixing configuration among the three elements where the qubit degree of freedom can be adiabatically eliminated, and thus results in the enhanced coupling between the two resonators. Therefore, our work constitutes the first step towards studying quantum nonlinear effect in circuit electromechanics.

  3. Investigation of strong motion processing procedures

    International Nuclear Information System (INIS)

    Rinaldi, D.; Goula, X.; Menu, J.M.

    1988-03-01

    The work which is described here presents preliminary results of an on-going research relating to the accurate recording and quality processing of earthquake strong ground motions. The work is the product of a tripartite co-operation between three European Centres (ENEA, PAS-ISP Laboratorio Ingengneria dei Siti, Rome/CEA, IPSN, Fontenay-aux-Roses, ICST, Department of Civil Engineering, London), which have carried out independently similar research in the recent past. Other European Institutes joined the three mentioned organizations for discussions during a Workshop (June 1985) held in Casaccia (ENEA Research Centre of Rome). The aim of the research is a thorough analysis of various factors affecting the recovery of true ground accelerations recorded with analogue instruments. The separate and cumulative effects of the type of recording accelerometer, the digitization equipment and the correction routines have been analysed. Global comparisons have been achieved to obtain a general insight into various standard processing procedures

  4. Quantization rules for strongly chaotic systems

    International Nuclear Information System (INIS)

    Aurich, R.; Bolte, J.

    1992-09-01

    We discuss the quantization of strongly chaotic systems and apply several quantization rules to a model system given by the unconstrained motion of a particle on a compact surface of constant negative Gaussian curvature. We study the periodic-orbit theory for distinct symmetry classes corresponding to a parity operation which is always present when such a surface has genus two. Recently, several quantization rules based on periodic orbit theory have been introduced. We compare quantizations using the dynamical zeta function Z(s) with the quantization condition cos(π N(E)) = 0, where a periodix-orbit expression for the spectral staircase N(E) is used. A general discussion of the efficiency of periodic-orbit quantization then allows us to compare the different methods. The system dependence of the efficiency, which is determined by the topological entropy τ and the mean level density anti d(E), is emphasized. (orig.)

  5. Transport phenomena in strongly correlated Fermi liquids

    CERN Document Server

    Kontani, Hiroshi

    2013-01-01

    In conventional metals, various transport coefficients are scaled according to the quasiparticle relaxation time, \\tau, which implies that the relaxation time approximation (RTA) holds well. However, such a simple scaling does not hold in many strongly correlated electron systems, reflecting their unique electronic states. The most famous example would be cuprate high-Tc superconductors (HTSCs), where almost all the transport coefficients exhibit a significant deviation from the RTA results. To better understand the origin of this discrepancy, we develop a method for calculating various transport coefficients beyond the RTA by employing field theoretical techniques. Near the magnetic quantum critical point, the current vertex correction (CVC), which describes the electron-electron scattering beyond the relaxation time approximation, gives rise to various anomalous transport phenomena. We explain anomalous transport phenomena in cuprate HTSCs and other metals near their magnetic or orbital quantum critical poi...

  6. Towards Integrated Marmara Strong Motion Network

    Science.gov (United States)

    Durukal, E.; Erdik, M.; Safak, E.; Ansal, A.; Ozel, O.; Alcik, H.; Mert, A.; Kafadar, N.; Korkmaz, A.; Kurtulus, A.

    2009-04-01

    Istanbul has a 65% chance of having a magnitude 7 or above earthquake within the next 30 years. As part of the preparations for the future earthquake, strong motion networks have been installed in and around Istanbul. The Marmara Strong Motion Network, operated by the Department of Earthquake Engineering of Kandilli Observatory and Earthquake Research Institute, encompasses permanent systems outlined below. It is envisaged that the networks will be run by a single entity responsible for technical management and maintanence, as well as for data management, archiving and dissemination through dedicated web-based interfaces. • Istanbul Earthquake Rapid Response and Early Warning System - IERREWS (one hundred 18-bit accelerometers for rapid response; ten 24-bit accelerometers for early warning) • IGDAŞ Gas Shutoff Network (100 accelerometers to be installed in 2010 and integrated with IERREWS) • Structural Monitoring Arrays - Fatih Sultan Mehmet Suspension Bridge (1200m-long suspension bridge across the Bosphorus, five 3-component accelerometers + GPS sensors) - Hagia Sophia Array (1500-year-old historical edifice, 9 accelerometers) - Süleymaniye Mosque Array (450-year-old historical edifice,9 accelerometers) - Fatih Mosque Array (237-year-old historical edifice, 9 accelerometers) - Kanyon Building Array (high-rise office building, 5 accelerometers) - Isbank Tower Array (high-rise office building, 5 accelerometers) - ENRON Array (power generation facility, 4 acelerometers) - Mihrimah Sultan Mosque Array (450-year-old historical edifice,9 accelerometers + tiltmeters, to be installed in 2009) - Sultanahmet Mosque Array, (390-year-old historical edifice, 9 accelerometers + tiltmeters, to be installed in 2009) • Special Arrays - Atakoy Vertical Array (four 3-component accelerometers at 25, 50, 75, and 150 m depths) - Marmara Tube Tunnel (1400 m long submerged tunnel, 128 ch. accelerometric data, 24 ch. strain data, to be installed in 2010) - Air-Force Academy

  7. Machine Learning Phases of Strongly Correlated Fermions

    Directory of Open Access Journals (Sweden)

    Kelvin Ch’ng

    2017-08-01

    Full Text Available Machine learning offers an unprecedented perspective for the problem of classifying phases in condensed matter physics. We employ neural-network machine learning techniques to distinguish finite-temperature phases of the strongly correlated fermions on cubic lattices. We show that a three-dimensional convolutional network trained on auxiliary field configurations produced by quantum Monte Carlo simulations of the Hubbard model can correctly predict the magnetic phase diagram of the model at the average density of one (half filling. We then use the network, trained at half filling, to explore the trend in the transition temperature as the system is doped away from half filling. This transfer learning approach predicts that the instability to the magnetic phase extends to at least 5% doping in this region. Our results pave the way for other machine learning applications in correlated quantum many-body systems.

  8. Neutrino oscillations in strong magnetic fields

    International Nuclear Information System (INIS)

    Likhachev, G.G.; Studenikin, A.I.

    1994-07-01

    Neutrino conversion processes between two neutrino species and the corresponding oscillations induced by strong magnetic fields are considered. The value of the critical strength of magnetic field B cr as a function of characteristics of neutrinos in vacuum (Δm 2 ν , mixing angle θ), effective particle density of matter n eff , neutrino (transition) magnetic moment μ-tilde and energy E is introduced. It is shown that the neutrino conversion and oscillations effects induced by magnetic fields B ≥ B cr are important and may result in the depletion of the initial type of ν's in the bunch. A possible increase of these effects in the case when neutrinos pass through a sudden decrease of density of matter (''cross-boundary effect'') and applications to neutrinos from neutron stars and supernova are discussed. (author). 25 refs

  9. Strong and electromagnetic interactions in hadron systems

    International Nuclear Information System (INIS)

    Aissat, N.; Amghar, A.; Cano, F.; Gonzalez, F.; Noguera, S.; Carbonell, J.; Desplanques, B.; Silvestre-Brac, B.; Karmanov, V.; Mathiot, J.F.

    1997-01-01

    The pionic strong decay amplitudes of baryon resonances are studied in a constituent quark model. Particular attention is given to the operator describing the transition. The nucleon form factors are calculated in a non-relativistic approach, with emphasis on the highest momentum transfers. The aim is to determine the ingredients that are essential in getting correct results and are likely to be required for a more realistic estimate in a fully relativistic approach. The deuteron form factors have been calculated in the light-front approach using wave functions determined in a perturbative way. The derivation of the neutron charge form factor from the deuteron structure function, A(q 2 ), is reanalyzed including further mesonic exchange contributions. (authors)

  10. Combinatorial description of space and strong interactions

    International Nuclear Information System (INIS)

    Zenczykowski, P.

    1988-01-01

    A reinterpretation is given of a successful phenomenological approach to hadron self-energy effects known as the unitarized quark model. General arguments are given that the proper description of strong interactions may require abandoning the assignment of a primary role to continuous concepts such as position and momentum in favor of discrete ones such as spin or W-spin. The reinterpretation exploits an analogy between the W-spin diagrams occurring in the calculations of hadronic loop effects and the spin network idea of Penrose. A connection between the S-matrix approach to hadron masses and the purely algebraic approach characteristic of the quark model is indicated. Several hadron mass relations generated by a resulting SU(6)/sub w/-group-theoretic expression are presented and discussed. Results of an attempt to generalize the scheme to the description of hadron vertices are reported

  11. Scaling of chaos in strongly nonlinear lattices.

    Science.gov (United States)

    Mulansky, Mario

    2014-06-01

    Although it is now understood that chaos in complex classical systems is the foundation of thermodynamic behavior, the detailed relations between the microscopic properties of the chaotic dynamics and the macroscopic thermodynamic observations still remain mostly in the dark. In this work, we numerically analyze the probability of chaos in strongly nonlinear Hamiltonian systems and find different scaling properties depending on the nonlinear structure of the model. We argue that these different scaling laws of chaos have definite consequences for the macroscopic diffusive behavior, as chaos is the microscopic mechanism of diffusion. This is compared with previous results on chaotic diffusion [M. Mulansky and A. Pikovsky, New J. Phys. 15, 053015 (2013)], and a relation between microscopic chaos and macroscopic diffusion is established.

  12. Study on characteristics of vertical strong motions

    International Nuclear Information System (INIS)

    Akao, Y.; Katukura, H.; Fukushima, S.; Mizutani, M.

    1993-01-01

    Statistic properties of vertical strong ground motions from near-field earthquakes are discussed in comparison with that of horizontal motions. It is a feature of this analysis that time history of each observed record is divided into direct P- and S-wave segments from a seismological viewpoint. Following results are obtained. Vertical motion energy excited by direct S-waves is about 0.6 times of horizontal ones at deep underground, and it approaches to 1.0 at shallow place. Horizontal motion energy excited by direct P-waves becomes 0.2 times (at deep) or more (at shallow) of vertical one. These results can be available in modeling of input motions for aseismic design. (author)

  13. Atomic physics of strongly correlated systems

    International Nuclear Information System (INIS)

    Lin, C.D.

    1986-01-01

    This abstract summarizes the progress made in the last year and the future plans of our research in the study of strongly correlated atomic systems. In atomic structure and atomic spectroscopy we are investigating the classification and supermultiplet structure of doubly excited states. We are also beginning the systematic study of triply excited states. In ion-atom collisions, we are exploring an AO-MO matching method for treating multi-electron collision systems to extract detailed information such as subshell cross sections, alignment and orientation parameters, etc. We are also beginning ab initio calculations on the angular distributions for electron transfer processes in low-energy (about 10-100eV/amu) ion-atom collisions in a full quantum mechanical treatment of the motion of heavy particles

  14. Strong crystal size effect on deformation twinning

    DEFF Research Database (Denmark)

    Yu, Qian; Shan, Zhi-Wei; Li, Ju

    2010-01-01

    plasticity. Accompanying the transition in deformation mechanism, the maximum flow stress of the submicrometre-sized pillars was observed to saturate at a value close to titanium’s ideal strength9, 10. We develop a ‘stimulated slip’ model to explain the strong size dependence of deformation twinning......Deformation twinning1, 2, 3, 4, 5, 6 in crystals is a highly coherent inelastic shearing process that controls the mechanical behaviour of many materials, but its origin and spatio-temporal features are shrouded in mystery. Using micro-compression and in situ nano-compression experiments, here we...... find that the stress required for deformation twinning increases drastically with decreasing sample size of a titanium alloy single crystal7, 8, until the sample size is reduced to one micrometre, below which the deformation twinning is entirely replaced by less correlated, ordinary dislocation...

  15. Noise Spectroscopy in Strongly Correlated Oxides

    Science.gov (United States)

    Alsaqqa, Ali M.

    Strongly correlated materials are an interesting class of materials, thanks to the novel electronic and magnetic phenomena they exhibit as a result of the interplay of various degrees of freedom. This gives rise to an array of potential applications, from Mott-FET to magnetic storage. Many experimental probes have been used to study phase transitions in strongly correlated oxides. Among these, resistance noise spectroscopy, together with conventional transport measurements, provides a unique viewpoint to understand the microscopic dynamics near the phase transitions in these oxides. In this thesis, utilizing noise spectroscopy and transport measurements, four different strongly correlated materials were studied: (1) neodymium nickel oxide (NdNiO 3) ultrathin films, (2) vanadium dioxide (VO2) microribbons, (3) copper vanadium bronze (CuxV2O 5) microribbons and (4) niobium triselenide (NbSe3) microribbons. Ultra thin films of rare-earth nickelates exhibit several temperature-driven phase transitions. In this thesis, we studied the metal-insulator and Neel transitions in a series of NdNiO3 films with different lattice mismatches. Upon colling down, the metal-insulator phase transition is accompanied by a structural (orthorohombic to monoclinic) and magnetic (paramagnetic to antiferromagnetic) transitions as well, making the problem more interesting and complex at the same time. The noise is of the 1/f type and is Gaussian in the high temperature phase, however deviations are seen in the low temperature phases. Below the metal-insulator transition, noise magnitude increases by orders of magnitude: a sign of inhomogeneous electrical conduction as result of phase separation. This is further assured by the non-Gaussian noise signature. At very low temperatures (T switches between Gaussian and non-Gaussian over several hours, possibly arising from dynamically competing ground states. VO2 is one of the most widely studied strongly correlated oxides and is important from the

  16. Strong quantum scarring by local impurities

    Science.gov (United States)

    Luukko, Perttu J. J.; Drury, Byron; Klales, Anna; Kaplan, Lev; Heller, Eric J.; Räsänen, Esa

    2016-11-01

    We discover and characterise strong quantum scars, or quantum eigenstates resembling classical periodic orbits, in two-dimensional quantum wells perturbed by local impurities. These scars are not explained by ordinary scar theory, which would require the existence of short, moderately unstable periodic orbits in the perturbed system. Instead, they are supported by classical resonances in the unperturbed system and the resulting quantum near-degeneracy. Even in the case of a large number of randomly scattered impurities, the scars prefer distinct orientations that extremise the overlap with the impurities. We demonstrate that these preferred orientations can be used for highly efficient transport of quantum wave packets across the perturbed potential landscape. Assisted by the scars, wave-packet recurrences are significantly stronger than in the unperturbed system. Together with the controllability of the preferred orientations, this property may be very useful for quantum transport applications.

  17. Functional calculus in strong plasma turbulence

    International Nuclear Information System (INIS)

    Ahmadi, G.; Hirose, A.

    1980-01-01

    The theory of electrostatic plasma turbulence is considered. The basic equations for the dynamics of the hierarchy of the moment equations are derived and the difficulty of the closure problem for strong plasma turbulence is discussed. The characteristic functional in phase space is introduced and its relations to the correlation functions are described. The Hopf functional equation for dynamics of the characteristic functional is derived, and its equivalence to the hierarchy of the moment equations is established. Similar formulations were carried out in velocity-wave vector space. The cross-spectral moments and the characteristic functional are considered and their relationships are studied. An approximate solution for Hopf's equation for the nearly normal turbulence is obtained which is shown to predict diffusion of the mean distribution function in velocity space. (author)

  18. Strong mobility in weakly disordered systems

    Energy Technology Data Exchange (ETDEWEB)

    Ben-naim, Eli [Los Alamos National Laboratory; Krapivsky, Pavel [BOSTON UNIV

    2009-01-01

    We study transport of interacting particles in weakly disordered media. Our one-dimensional system includes (i) disorder, the hopping rate governing the movement of a particle between two neighboring lattice sites is inhomogeneous, and (ii) hard core interaction, the maximum occupancy at each site is one particle. We find that over a substantial regime, the root-mean-square displacement of a particle s grows superdiffusively with time t, {sigma}{approx}({epsilon}t){sup 2/3}, where {epsilon} is the disorder strength. Without disorder the particle displacement is subdiffusive, {sigma} {approx}t{sup 1/4}, and therefore disorder strongly enhances particle mobility. We explain this effect using scaling arguments, and verify the theoretical predictions through numerical simulations. Also, the simulations show that regardless of disorder strength, disorder leads to stronger mobility over an intermediate time regime.

  19. Pentacene Excitons in Strong Electric Fields.

    Science.gov (United States)

    Kuhnke, Klaus; Turkowski, Volodymyr; Kabakchiev, Alexander; Lutz, Theresa; Rahman, Talat S; Kern, Klaus

    2018-02-05

    Electroluminescence spectroscopy of organic semiconductors in the junction of a scanning tunneling microscope (STM) provides access to the polarizability of neutral excited states in a well-characterized molecular geometry. We study the Stark shift of the self-trapped lowest singlet exciton at 1.6 eV in a pentacene nanocrystal. Combination of density functional theory (DFT) and time-dependent DFT (TDDFT) with experiment allows for assignment of the observation to a charge-transfer (CT) exciton. Its charge separation is perpendicular to the applied field, as the measured polarizability is moderate and the electric field in the STM junction is strong enough to dissociate a CT exciton polarized parallel to the applied field. The calculated electric-field-induced anisotropy of the exciton potential energy surface will also be of relevance to photovoltaic applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Designing asymmetric multiferroics with strong magnetoelectric coupling

    Science.gov (United States)

    Lu, Xuezeng; Xiang, Hongjun; Rondinelli, James; Materials Theory; Design Group Team

    2015-03-01

    Multiferroics offer exciting opportunities for electric-field control of magnetism. Single-phase multiferroics suitable for such applications at room temperature need much more study. Here, we propose the concept of an alternative type of multiferroics, namely, the ``asymmetric multiferroic.'' In asymmetric multiferroics, two locally stable ferroelectric states are not symmetrically equivalent, leading to different magnetic properties between these two states. Furthermore, we predict from first principles that a Fe-Cr-Mo superlattice with the LiNbO3-type structure is such an asymmetric multiferroic. The strong ferrimagnetism, high ferroelectric polarization, and significant dependence of the magnetic transition temperature on polarization make this asymmetric multiferroic an ideal candidate for realizing electric-field control of magnetism at room temperature. Our study suggests that the asymmetric multiferroic may provide an alternative playground for voltage control of magnetism and find its applications in spintronics and quantum computing.