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  • 1
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Perturbative experiments on the Tokamak Fusion Test Reactor [Phys. Plasmas 4, 1736 (1997)] (TFTR) have investigated transport in reverse shear plasmas. On TFTR, reverse magnetic shear plasmas bifurcate into two states with different transport properties: reverse shear (RS) and enhanced reverse shear (ERS) with improved core confinement. Measurements of the 14 MeV t(d,n)α neutrons and charge-exchange recombination radiation spectra are used to infer the trace tritium and helium profiles, respectively. The profile evolution indicate the formation of core particle transport barriers in ERS plasmas. The transport barrier is manifested by an order-of-magnitude reduction in the particle diffusivity (DT,DHe) and a smaller reduction in the pinch within the reverse shear region. The low diffusivities are consistent with neoclassical predictions. Furthermore, DT and DHe(approximate)χeff, the effective thermal diffusivity. Although the measured coefficients imply no helium ash accumulation, the situation is uncertain in a reactor due to unknown χeff scaling.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 5 (1998), S. 1062-1067 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Fueling of the plasma core by recycling in the Tokamak Fusion Test Reactor [Phys. Plasmas 2, 2176 (1995)] has been studied. In plasmas fueled by deuterium recycled from the limiter and tritium-only neutral beam injection, the DT neutron rate provides a measure of the deuterium influx into the core plasma. A reduced influx with plasmas using lithium pellet conditioning and with plasmas of reduced major (and minor) radius is found. Modeling with the DEGAS [D. P. Stotler et al., Phys. Plasmas 3, 4084 (1996)] neutrals code shows that the dependence on radius can be related to the penetration of neutrals through the scrape-off layer. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 3125-3128 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoluminescence (PL) and Raman scattering measurements have been carried out to investigate the hydrogenation and annealing effects in p-type ZnSe epilayers grown on n-type GaAs (100) substrates by molecular beam epitaxy. After hydrogenation, the PL spectra showed that the deep acceptor-bound exciton peak disappeared and that the peak position of the donor–acceptor pair peak shifted to a higher energy. When the hydrogenated ZnSe/GaAs heterostructure was annealed at 300 °, a bound exciton due to neutral acceptors appeared. The Raman intensity of the plasma longitudinal optical-phonon-coupling mode increased after hydrogenation. These results indicate that the crystallinity of the p-type ZnSe epilayers grown on n-type GaAs substrates is improved by hydrogenation and that hydrogenated and annealed ZnSe films grown on GaAs substrates hold promise for potential application as buffer layers for the growth of Zn1−xMgxSySe1−y active layers. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 2014-2018 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Sn-doped In0.5Ga0.5P epilayers, grown on semi-insulating (100) GaAs substrates by the liquid phase epitaxy technique, have been investigated using photoluminescence and Hall effect measurements from 15 to 300 K. The Sn dopant in InGaP shows amphoteric behavior with a compensation ratio of ∼0.4–0.6. Transitions involving shallow Sn acceptors have been identified through photoluminescence measurements for the first time and the ionization energy of Sn was determined to be 57 meV, which is in good agreement with the hydrogenic acceptor value. It was also found that the Sn shallow donor has an ionization energy 17–12 meV with increasing carrier concentrations through Hall measurements. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 1527-1530 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature dependent Hall mobility and carrier concentration of In0.5Ga0.5P epilayers grown on (100) semi-insulating GaAs substrates by the liquid phase epitaxy technique have been investigated in the range of 77–300 K. The electron mobility and carrier concentration were of the order of 806 cm2 V−1 s−1, and 6.5×1016 cm−3, respectively at 300 K. The model (taking into account ionized impurity, alloy and space-charge scattering mechanisms) is considered in order to properly portray the observed features of the electron mobility results. The theoretical prediction is in good agreement with the observed results. The electron mobility was limited by ionized scattering up to 120 K and was also limited by alloy, space-charge scattering up to 300 K. It was found that the space-charge scattering has a stronger temperature dependence, T−1, than the usual T−0.5 and the In0.5Ga0.5P epilayer was heavily compensated for having an acceptor concentration of NA=8.5×1016 cm−3 with a compensation ratio of 0.5. © 1998 American Institute of Physics.
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of communication 48 (1998), S. 0 
    ISSN: 1460-2466
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Media Resources and Communication Sciences, Journalism
    Notes: Postwar trends in international communication research reveal that the three main paradigms-modernization, dependency, and postdependency-have theoretical and methodological limitations for analyzing the complexities of cultural practices in the contemporary era. The limitations arise from the narrow theoretical concern centered on the polarity between development and dependency, and the overemphasis of economic forces at the expense of cultural forces. In this essay I urge a focus on cultural dynamics to reflect rapidly changing conditions of integration and disintegration among diverse cultural forces in a global society. The concepts and methods in postmodern cultural studies can facilitate this theoretical shift. The Gramscian concept of hegemony allows us to explore the economic aspect of cultural production by media industries and the cultural ideological aspect of audience readings within a single research framework.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effects of La content and rapid thermal annealing (RTA) on the capacitance (C–V) and leakage current (J–E) properties of the PLT films were investigated. The films were deposited on Pt/Ti/SiO2/Si substrates at 480 °C by electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR PECVD). The La doped films showed slim P–E hysteresis curves and almost no frequency dependency of permittivity. As the La content increased beyond 11%, Pb was excessively incorporated into the PLT film, resulting in non-stoichiometric compositions with (Pb+La)/Ti〉1, degraded crystallinity and decreased capacitance. After RTA at 700 °C, C–V curves became symmetric and leakage current characteristics were improved, but the crystallinity and the ferroelectricity of the films were not so much improved although the film became stoichiometric. The leakage current of the films was controlled by Schottky conduction except for the low electric field region where the trap current of mobile charges or hopping conduction appeared to be dominant. In order to explain the RTA dependence of the C–V shift and the polarity dependence of the J–E characteristics of the PLT films, a physical model was suggested, based on the surface states and Pb vacancies, which affects the width of the space charge region and the height of the Schottky barrier. © 1998 Kluwer Academic Publishers
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    International orthopaedics 22 (1998), S. 321-324 
    ISSN: 1432-5195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé. Les dommages osseux importants dans les fractures ouvertes du Tibia sont généralement traités par une greffe osseuse conventionelle: on utilise soit une greffe de péroné vascularisée, soit la technique du fixateur (type llizarov). Une greffe de péroné vascularisée peut être meilleure qu’une greffe osseuse conventionnelle, mais c’est une greffe qui est techniquement, difficile et parfois impossible à réaliser. Dans ce cas, le transfert du péroné avec l’utilisation du fixateur externe (type Ilizarov) est une méthode alternative. Cette opération peut être accomplie en transférant la partie ostéotomisée du péroné sur le Tibia au moyen de cables «olives». Récemment, un jeune homme de 20 ans a présenté une fracture ouverte du Tibia de type Gustilo IIIb. Les dommages causés aux tissues étaient sévères. Seule l’artère tibiale postérieure était perméable et l’artère péronéale était partiellement endommagée. Un recouvrement par lambeau de grand dorsal fût réalisé afin de couvrir les tissues endommagés. Le seule artère tibiale postérieure étant déjà utilisé pour le recouvrement, il était difficile de réaliser une greffe de péroné vascularisée. De plus il était techniquement difficile d’accomplir un déplacement graduel en utilisant la fixateur externe (type Ilizarov) car la partie distale du Tiba était perdue. Ainsi, un transfert de péroné fût immédiatement réalisé avoir appliqué le fixateur externe. Une bonne fusion osseuse, ainsi qu’une hypertrophie du péronée ont été obtenues, bien que ces 2 opérations aient été effectuées simultanément.
    Notes: Abstract. Massive segmental bony defects in open tibial fractures are generally treated with conventional bone grafting, a free vascularised fibular graft or the ring fixator technique. A vascularised fibular graft may be superior to a conventional bone graft, but it is technically difficult and occasionally impossible. In such circumstances, fibular transfer in conjunction with a ring fixator is an alternative method. This procedure can be accomplished by transferring the osteotomised part of the fibula to the tibia by means of olive wires. The authors have treated a 20-year-old male who presented with a Gustilo type IIIB open tibial fracture. The soft tissue defect was severe, only the tibialis posterior artery was patent and the peroneal artery was partially damaged. A latissimus dorsi flap was performed to cover the soft tissue defect. Since the patent tibialis posterior artery had already been used for the flap, it was difficult to perform a vascularised fibular graft. Moreover, it was technically difficult to accomplish a gradual transport using a ring fixator because the distal tibia was lost. For this reason, the fibular transfer was performed immediately after the ring fixator was applied. Good bony union and fibular hypertrophy were obtained even though these two procedures were undertaken simultaneously.
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  • 9
    ISSN: 1432-0649
    Keywords: PACS: 32.80.Rm; 34.50.Fa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 17 (1998), S. 2083-2085 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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