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13. |
- Malcheva, G, et al.
(author)
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Radiative lifetimes and transition probabilities of astrophysical interest in ZrII
- 2006
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In: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 1365-2966 .- 0035-8711. ; 367:2, s. 754-762
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Journal article (peer-reviewed)abstract
- Radiative lifetimes of 16 odd levels belonging to the 4d(2)5p configuration of Zr II have been measured using a time-resolved laser-induced fluorescence technique with a single-step excitation process either from the ground state or from metastable levels belonging to the 4d(2)5s and 4d(3) configurations. For 12 levels, there were no previous results available. The new experimental results and the lifetime values available in the literature have allowed to test a theoretical relativistic Hartree-Fock (HFR) model including core-polarization effects and to deduce transition probabilities for 242 transitions of astrophysical interest in the range 187.8-535.0 nm.
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14. |
- Mayo, R., et al.
(author)
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Radiative lifetimes of Zr III excited levels
- 2006
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In: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 40:2, s. 169-173
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Journal article (peer-reviewed)abstract
- We report on radiative lifetimes of 4d5p excited states of Zr III produced in a laser produced plasma. The ions were populated either in the ground state or in metastable states, and the number of ions is strongly dependent on the application of an external magnetic field, which is shown to be very important when using the time-resolved laser-induced fluorescence technique for lifetime measurements in highly charged ions. The experimental lifetime results fall in the region 1-2 ns with statistical uncertainties less than 7%. The experimental values were compared with multi-configuration Hartree-Fock calculations showing an agreement within 12-20%. The experimental values are systematically higher than the theoretical ones.
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15. |
- Pecoits-Filho, R, et al.
(author)
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Overview of peritoneal dialysis in Latin America
- 2007
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In: Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis. - 0896-8608. ; 27:3, s. 316-321
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Journal article (peer-reviewed)
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16. |
- Tomasi, C., et al.
(author)
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Aerosols in polar regions : A historical overview based on optical depth and in situ observations
- 2007
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In: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 112:D16, s. D16205-
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Research review (peer-reviewed)abstract
- Large sets of filtered actinometer, filtered pyrheliometer and Sun photometer measurements have been carried out over the past 30 years by various groups at different Arctic and Antarctic sites and for different time periods. They were examined to estimate ensemble average, long-term trends of the summer background aerosol optical depth AOD(500 nm) in the polar regions ( omitting the data influenced by Arctic haze and volcanic eruptions). The trend for the Arctic was estimated to be between -1.6% and -2.0% per year over 30 years, depending on location. No significant trend was observed for Antarctica. The time patterns of AOD( 500 nm) and angstrom ngstrom's parameters a and beta measured with Sun photometers during the last 20 years at various Arctic and Antarctic sites are also presented. They give a measure of the large variations of these parameters due to El Chichon, Pinatubo, and Cerro Hudson volcanic particles, Arctic haze episodes most frequent in winter and spring, and the transport of Asian dust and boreal smokes to the Arctic region. Evidence is also shown of marked differences between the aerosol optical parameters measured at coastal and high-altitude sites in Antarctica. In situ optical and chemical composition parameters of aerosol particles measured at Arctic and Antarctic sites are also examined to achieve more complete information on the multimodal size distribution shape parameters and their radiative properties. A characterization of aerosol radiative parameters is also defined by plotting the daily mean values of a as a function of AOD( 500 nm), separately for the two polar regions, allowing the identification of different clusters related to fifteen aerosol classes, for which the spectral values of complex refractive index and single scattering albedo were evaluated.
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