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  • Springer  (714)
  • American Physical Society (APS)  (67)
  • EDP Sciences  (21)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 49 (1990), S. 325-340 
    ISSN: 1436-4646
    Keywords: Convex quadratic programming ; interior point method ; Karmarkar's method ; logarithmic barrier function method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We present a primal interior point method for convex quadratic programming which is based upon a logarithmic barrier function approach. This approach generates a sequence of problems, each of which is approximately solved by taking a single Newton step. It is shown that the method requires $$O(\sqrt n L)$$ iterations and O(n 3.5 L) arithmetic operations. By using modified Newton steps the number of arithmetic operations required by the algorithm can be reduced to O(n 3 L).
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Iron-doped semi-insulating InP has been grown by chloride vapour-phase epitaxy (VPE) using nitrogen mixed with hydrogen as carrier. Reducing hydrogen partial pressure by the introduction of nitrogen greatly improves the transport of FeCl2. The influence of hydrogen partial pressure on the Fe transport, and therefore on the Fe incorporation, has been studied theoretically and experimentally. With a relatively slow growth rate, InP film with a high Fe concentration is easily obtained. Quantum-well laser diodes with semi-insulating InP(Fe) stripe-confinement have been fabricated successfully.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Optical and quantum electronics 32 (2000), S. 1325-1331 
    ISSN: 1572-817X
    Keywords: chromaticity ; multiple-quantum-well ; organic electroluminescence ; white-light emission
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Organic multiple quantum wells (MQWs) white light emitting devices are fabricated in which blue fluorescent dye, a trimer of N-anylbenzimidazole (TPBI) and orange fluorescent rubrene doped tris (8-hydroxyquinoline) Aluminum act as quantum-well light emitting layers between triphenyldiamine derivative (TPD) potential barrier layers, and aluminium complex (Alq) act as an electron transporter and green emitter. The injected carriers are confined in different quantum wells and Alq layer. The white light emission comes from a combination of photons generated in different light emitting layers. The Commission Internationale de l' Eclairage (CIE) coordinates of the emitted light are tuned by increasing the number of TPBI wells due to its low fluorescent efficiency compared with rubrene.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Optical and quantum electronics 29 (1997), S. 697-709 
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The multi-well energy representation technique is presented for the analysis of the valence band structures of multiple quantum well (MQW) lasers. In terms of this technique and its relative formulae, calculations are performed for InGaAs/InGaAsP strained MQW structures. It is found that the coupling exists between the wells, and causes the energy split. So, on the basis of the computed results, the coupling between the wells is analysed, and the split of both the quantized energy levels at the Γ point and the quantized energy bands at the non-Γ points is described. It is also found that the structural parameters of the MQW system strongly influence the coupling property and the energy split, and hence these effects are also discussed in relation to the periodic length, the well width, the distance between the wells, and the ratio of the well width to the periodic length.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 70 (2000), S. 673-675 
    ISSN: 1432-0630
    Keywords: PACS: 81.10; 82.30; 75
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. In this paper, we report the catalytic synthesis of carbon nanotubes filled with long continuous cobalt nanowires by a simple chemical process. The average diameter of the multi-walled nanotubes is about 40 nm. The nanowires are a few micrometers long with a diameter of 20 nm. X-ray diffraction analysis reveals that the as-prepared material, following treatment with HCl, shows the cobalt nanowires, encapsulated in the carbon nanotubes, as having an fcc and not the table hexagonal structure. The filled nanotubes can be seperated by using a permanent magnet. TEM, XPS and Raman spectroscopy were also used to analyze the products.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 54 (1992), S. 247-258 
    ISSN: 1432-0649
    Keywords: 42.65 ; 42.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The standard four wave mixing model in a sluggish photorefractive medium is used to calculate the transient response of a phase conjugate resonator. General trends are unveiled and discussed in view of the possible use of the system in image processing. Experimental results are shown to confirm qualitatively the predicted behaviour.
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  • 7
    ISSN: 1432-0649
    Keywords: 42.65.Hw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We derived the coupling equations of two-wave coupling in photorefractive crystals in 90° geometry where pump and signal beams enter two mutually orthogonal crystal faces vertically. We solved the equations numerically in the case of non-local response and illustrated the influence of the coupling coefficientΓ, the absorption coefficient α and the ratio of intensities of the two incident beams,R, on the inhomogeneity of transmitted pump and signal beams.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 5 (1988), S. 276-281 
    ISSN: 1432-0789
    Keywords: Metolachlor ; Biodegradation ; Soil perfusion ; Microbial metabolites ; Dechlorination ; Actinomyces spp.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Degradation of the herbicide metachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] was studied in a soil perfusion system. After 28 days of perfusion, the 14CO2 evolved from a Virginia soil (soil A), which had been previously treated with metolachlor (Dual) for 5 years, accounted for 18.4% of the added 14C-metolachlor, while only 3.5% of the 14C was liberated as 14CO2 from a soil of the same field which had no history of Dual treatment (soil B). No 14CO2 was liberated from γ-irradiated soil A. After incubation, metolachlor constituted almost all the extractable 14C in sterile soil A, while about 20% of the added 14C extracted from non-sterile soil A consisted of products of metolachlor; 14.8% was identified as dechlorinated metolachlor. No mineralization occurred in actinomycete-inoculated sterile soil A, but 30% of the added 14C was recovered in the form of transformation products of metolachlor. Our results demonstrate clearly that microbial activity is responsible for the mineralization of metolachlor, and that degradation is enhanced in herbicide-acclimated soils.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 20 (1971), S. 282-285 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 23 (1972), S. 289-291 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
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