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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 6211-6211 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Epitaxial films of Cr were grown at 200 °C on Fe(100). The magnetic order of the Cr overlayers was studied by spin polarized electron energy loss spectroscopy (SPEELS). The exchange scattering asymmetry is large (negative) for the bare Fe surface and rapidly drops with increasing Cr coverage in the submonolayer range changing sign at around one monolayer Cr. This shows directly the antiferromagnetic coupling of the first Cr layer to the Fe substrate. With further increase in the Cr thickness the exchange asymmetry oscillates with a period of about 2 layers, thus proving directly the layer-by-layer antiferromagnetic order in the Cr films. The oscillation amplitude shows variations with thickness resembling features found in the magnetic coupling in Fe/Cr/Fe sandwiches. The SPEELS spectra show a maximum in the spin flip channels around 1.9 eV. This structure broadens with increasing Cr thickness. This large spin flip energy suggests a surface enhanced exchange splitting and an enhanced Cr surface moment.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Surface magnetic properties of epitaxial Gd(0001) films grown on W(110) were studied with spin-polarized resonant 4f photoemission. Films grown at room temperature and subsequently annealed to 550 °C show 66% polarization at 150 K, whereas films grown at 400 °C show only 46% polarization. Both types of films exhibit surface enhanced magnetic order, with the highest observed surface critical temperature exceeding the bulk value by as much as 60 K. For the first time, a rich variety of novel surface magnetic phenomena, i.e., sizeable perpendicular polarization component and unusual temperature hysteresis in the spin polarization, are observed, demonstrating that surface magnetic reconstruction is present in Gd(0001) films.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 47 (1925), S. 2792-2796 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 87 (1987), S. 660-663 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The diffusion coefficient of Ba (6s5d 3DJ) in noble gases was measured with a modulation/lock-in technique. This technique relies on a cylindrically symmetric source for the metastable state, and is independent of cell geometry. It is readily generalizable to other systems where the creation rate of a long-lived state can be modulated.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 4949-4957 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In this paper we present near-infrared absorption, thermal emission, and laser-induced fluorescence spectra obtained in high density sodium–potassium mixtures. These spectra are compared to spectra calculated from recently published NaK potentials and dipole moments and the agreement is seen to be quite good. We have also observed significant laser-induced fluorescence to the red of the 2 1∑+ → 1 1∑+ NaK band (A band). From laser power and density dependences of this long-wavelength fluorescence, as well as from comparison to calculated spectra, we have tentatively identified this emission as the lowest NaK triplet band 1 3∏ → 1 3∑+ which has not previously been reported. We have also observed a shoulder or satellite feature in potassium vapor under similar conditions. It is possible that this is a potassium trimer emission band.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 1358-1363 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: This is a study of the deexcitation mechanisms of the metastable 5 2D3/2 state of Ba+ in about 1 atm He buffer gas in the temperature range of 500–650 °C. The ions were produced by three-photon ionization with light tuned to a resonance between two excited states of Ba, enabling the electron density to be varied independently of the temperature and pressure. The deexcitation is dominated by superelastic scattering of electrons with a cross section of σse =45±20 A(ring)2 (corresponding to an electron-impact excitation cross section of 11 A(ring)2) and quenching by Ba atoms with a cross section of σBa =130±25 A(ring)2. No dependence of the deexcitation rate on He density was detected, and we infer an upper limit on the cross section of σHe ≤9×10−22 cm2.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 2 (1990), S. 390-399 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The flow field behind attached ring-type turbulence promoters of various sizes in a smooth pipe has been investigated by measuring the mean velocity and turbulence intensity profiles for downstream distances up to 100 promoter heights at a Reynolds number of 20 500 (based on pipe diameter and average velocity). Measurements have been limited to distances downstream of the flow reattachment region. The results indicate that for the smallest tested promoter with nondimensional height h+=12.5, the disturbance introduced does not have much influence in the core region and the flow behind the promoter reorganizes and recovers very quickly (within a streamwise distance equivalent to 20–30 promoter heights). On the other hand, for the largest promoter tested (h+=100), the flow in the core is significantly perturbed and the return of the flow to a self-preserving state has not been achieved, even at a downstream distance of 100 promoter heights. Furthermore,the mean velocity profile in the core region of the pipe with the largest promoter is much more uniform than the corresponding smooth pipe profile, indicating enhanced mixing. The longitudinal turbulence energy spectra in the sublayer, buffer layer, and logarithmic layer suggest that the sublayer structures are maintained and/or enhanced by large wallward motions originated in the core. These results are fairly consistent with the vortex model of Kobashi and Ichijo [Exp. Fluids 4, 49 (1986)].
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 27 (1955), S. 1129-1130 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 1356-1358 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We describe a method for frequency narrowing commercial high power diode lasers from 2 to 0.1 nm bandwidth with modest loss of power (〈2 dB). The resulting laser light is well suited for spin-exchange optical pumping, and we demonstrate that the polarization produced by a 2.5 W narrowband laser exceeds that of a 15 W array by 40% in our optical pumping system. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Plant pathology 49 (2000), S. 0 
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Global severity of potato late blight was estimated by linking two disease forecast models, Blitecast and Simcast, to a climate data base in a geographic information system (GIS). The disease forecast models indirectly estimate late blight severity by determining how many sprays are needed during a growing season as a function of the weather. Global zonation of estimated late blight severity was similar for both forecast models, but Blitecast generally predicted a lower number of sprays. With both forecast models, there were strong differences between potato production zones. Zones of high late blight severity include the tropical highlands, western Europe, the east coast of Canada and northern USA, south-eastern Brazil and central-southern China. Major production zones with a low late blight severity include the western plains in India, where irrigated potato is produced in the cool dry season, north-central China, and the north-western USA. Using a global GIS data base of potato production, the average number of sprays was calculated by country. These averages were compared with estimates of current fungicide use. The results using Blitecast and Simcast were correlated but only Blitecast estimates correlated with observed data for developed countries. The estimated number of sprays, whether from Blitecast or Simcast, did not correlate with the observed number of sprays in developing countries, and in a number of developing countries the predicted optimal number of sprays was much higher than the actual number observed. In these countries, increased access to host resistance and fungicides could have a strong economic impact.
    Type of Medium: Electronic Resource
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