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  • Springer  (67)
  • American Geophysical Union  (2)
  • American Institute of Physics (AIP)  (2)
  • American Physical Society (APS)  (2)
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 5072-5078 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Room-temperature photoluminescence decay time measurements in heavily doped GaAs:C-layers designed as base layers for heterojunction bipolar transistors are reported. These measurements provide access to nonequilibrium minority carrier lifetimes that determine the current gains of those devices. By systematically studying transient luminescence spectra over a wide range of excitation densities between 1013 and 1018 cm−3, we demonstrate the importance of carrier trapping processes at low excitation densities. Optimized excitation conditions that achieve trap saturation but also avoid stimulated emission are found for densities of (1–3)×1017 cm−3/pulse. Detection is limited to a spectral window well above the energy gap (beyond 1.5 eV). Values for both Auger and radiative recombination coefficients are given. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 846-848 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The short-period (GaAs)n1(AlAs)n2 superlattices with parameters (n1,n2)=(21,25), (6,42), (14,16), and (23,8) have been grown by molecular beam epitaxy on GaAs substrates along the [012] direction and characterized by x-ray and Raman scattering spectroscopy. The appearance of distinct satellite peaks around the Bragg reflections demonstrates the formation of high quality superlattices. The observed TO and LO confined modes have frequencies which map closely those of the optical phonons of bulk GaAs and AlAs in the Γ-W-X direction.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 174 (1963), S. 314-325 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The physical consequences emerging from a theory stated byKraichnan are considered with regard to isotropic hydromagnetic turbulence. This theory involves the direct-interaction approximation retaining the phase correlation within each triad of Fourier amplitudes. These interactions are suggested to be very important in hydromagnetic turbulence. Hydrodynamic as well as magnetic impulse-response function and time-correlation are unequivocally the same. This result suggests the existence of a universal equilibrium range. Within the inertial range the total energy spectrumE g (k)=E(k)+E m (k) obeys the same law as in hydrodynamic turbulenceE(k). The valueE m (k)≈E(k) corresponds roughly to maximum energy flux through this range. The magnetic energy flux decreases rapidly for eddies with larger wave-numbers within the range of ohmic ≫ viscous dissipation.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 159 (1960), S. 194-211 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Force-free magnetic fields are defined by the equation rot $$\mathfrak{H} = \alpha \mathfrak{H}$$ . Making use of a moving Frenet coordinate system $$(\mathfrak{t} = tangential, \mathfrak{n} = normal, \mathfrak{b} = binormal unit vector)$$ we find the following general features of these fields: 1. grad $$\left| \mathfrak{H} \right|$$ is always parallel to the osculating plane of the $$\mathfrak{H}$$ -lines. 2. If the lines of force are rectilinear within a finite region of space, the component of grad $$\left| \mathfrak{H} \right|$$ along $$\left| \mathfrak{H} \right|$$ must be zero for a force-free field with rot . 3. The factor of proportionality $$\alpha = \alpha (\mathfrak{r})$$ and $$\mathfrak{H}$$ can be calculated by means of two equations involving only the direction of $$\left| \mathfrak{H} \right|$$ . For several models of force-free fields the effect of symmetry assumptions on $$\alpha = \alpha (\mathfrak{r})$$ is discussed using special coordinate systems. In the appendix it is pointed out that a particle drift arises in magnetic fields with .
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 54 (1929), S. 811-818 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Zusammenfassung Die Fluoreszenz des Quecksilberdampfes bei polarisierter stufenweiser Anregung mit den Linien 2537 und 4047 unter Stickstoffzusatz wird untersucht und die dabei auftretenden Polarisationseffekte und Intensitätsversehiebungen der Fluoreszenzlinien 5461, 4358 und 4047 werden beschrieben und erklärt. Einige wichtige Folgerungen und weitere Untersuchungsmöglichkeiten werden diskutiert.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 81 (1933), S. 539-542 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Zusammenfassung Die Methode von Frl. Kohn, mit Hilfe der Spektrallinienuinkehr die Temperatur eines Gasvolumens zu bestimmen, wird auf den Lichtbogen angewandt und es wird mit ihr die Temperatur des Wechselstromlichtbogens im Spannungs-Nulldurchgang gemessen.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of environmental contamination and toxicology 29 (1982), S. 416-421 
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    De economist 31 (1882), S. 49-56 
    ISSN: 1572-9982
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 1 (1964), S. 163-169 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' journal of analytical chemistry 360 (1998), S. 679-682 
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract N-Nitroso-triazine herbicide species were synthesized as reference standards and their reaction products were separated by TLC. The method was established for analytical as well as for preparative amounts to achieve a sufficient separation between the educts, the byproducts and the N-nitrosated moieties. Separation of the reaction mixture was performed by two-dimensional TLC, using different mobile phases for each dimension. In the second dimension two developments were executed using the same solvent mixture. To examine the quality of performance, the separation zones were scrapped off, extracted and analyzed in the HPLC-diode array detection (DAD) mode in comparison with standards of the educts and the products of their N-nitrosation. This method minimizes the contact with the resulting N-nitroso compounds. At present nothing is known about the toxicological relevance or risk assessment on human health of N-nitrosocyanazine or N-nitrosoterbuthylazine species. Therefore the practical handling of these putative mutagenic and carcinogenic substances should be seen under the aspect of precaution and prevention of contamination.
    Type of Medium: Electronic Resource
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