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  • 1
    Electronic Resource
    Electronic Resource
    Bounds for Generalized Thrackles (2000)
    Springer
    Discrete & computational geometry 23 (2000), S. 191-206 
    Details
    ISSN: 1432-0444
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract. A thrackle (resp. generalized thrackle) is a drawing of a graph in which each pair of edges meets precisely once (resp. an odd number of times). For a graph with n vertices and m edges, we show that, for drawings in the plane, m≤ (2/3)(n-1) for thrackles, while m≤ 2n-2 for generalized thrackles. This improves theorems of Lovász, Pach, and Szegedy. The paper also examines thrackles in the more general setting of drawings on closed surfaces. The main result is: a bipartite graph G can be drawn as a generalized thrackle on a closed orientable connected surface if and only if G can be embedded in that surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009495
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Very Low Frequency Noise at Brisbane (1962)
    [s.l.] : Nature Publishing Group
    Nature 194 (1962), S. 962-962 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] This type of noise has now been recorded at Brisbane using equipment consisting of a loop of 1,440 sq. metres effective cross-section oriented for north-south directivity, a high-gain audio-amplifier and an asymmetric integrator of the type described by Ellis2. This method of recording makes use of ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/194962a0
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  • 3
    Electronic Resource
    Electronic Resource
    Prism coupler with variable coupling gap (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 4208-4212 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The construction and operation of a prism/variable-gap/sample system (or variable-gap Otto coupler) for the excitation of surface electromagnetic modes is reported. This system has been used for the observation and characterization of surface plasmon polaritons on thin film structures. The initial alignment of prism and sample is performed under gravity and the subsequent gap variation is performed by means of a single actuator operating a flexure stage on which the prism is mounted. The flexure stage ensures the maintenance of good parallelism between sample and prism as the gap dimension is varied. The coupler has also served as a prototype, in terms of design principle, for the construction of a more sophisticated, variable-gap Otto coupler that can operate in vacuum at temperatures from ambient to 85 K. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1313803
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  • 4
    Electronic Resource
    Electronic Resource
    Variable temperature, variable-gap Otto prism coupler for use in a vacuum environment (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 4213-4222 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The field of surface polariton physics really took off with the prism coupling techniques developed by Kretschmann and Raether, and by Otto. This article reports on the construction and operation of a rotatable, in vacuo, variable temperature, Otto coupler with a coupling gap that can be varied by remote control. The specific design attributes of the system offer additional advantages to those of standard Otto systems of (i) temperature variation (ambient to 85 K), and (ii) the use of a valuable, additional reference point, namely the gap-independent reflectance at the Brewster angle at any given, fixed temperature. The instrument is placed firmly in a historical context of developments in the field. The efficacy of the coupler is demonstrated by sample attenuated total reflectance results on films of platinum, niobium, and yttrium barium copper oxide and on aluminum/gallium arsenide (Al/GaAs) Schottky diode structures. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1313804
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  • 5
    Electronic Resource
    Electronic Resource
    Preliminary studies of radiation coupling between remote soft X-ray laser amplifiers (1994)
    Springer
    Applied physics 58 (1994), S. 51-56 
    Details
    ISSN: 1432-0649
    Keywords: 42.60.By ; 42.60.Kg ; 42.10.Mg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Coupling of a soft X-ray laser beam with a relaying concave mirror in a sequentially pumped amplifier geometry using the Ne-like Ge system has been studied experimentally. Preliminary observations indicate an increase in the spatial coherence of the amplified relayed beam. In addition, near-field imaging of one of the amplifier plasmas shows a double-lobed intensity pattern of the emergent beam indicating refractive guiding of the amplified beam with components both normal and tangential to the target surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01081713
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