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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Electrical engineering 76 (1992), S. 41-47 
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents This paper presents fast algorithms for the assistance of the power system engineer in the control center finding proper control actions to correct abnormal power system operating states. To correct abnormal bus voltages and reactive power a segmentation approach is introduced, which is based on a demand-specific selection of controls. The approach utilizes the property that capacitor/reactor switching actions have a limited topological sphere of influence only. This means that only those control devices, which are in the vicinity of each location where an abnormal power system state is identified, need to be considered for remedial actions. Branch switching actions used to alleviate overloaded system components result in strong structural changes of the network configuration so that these controls must be separated from other controls that can be represented by linearized mathematical models. A fast method is introduced, which is based on the analysis of changes of the bus impedance matrix caused by branch switching actions.
    Notes: Übersicht Ziel dieses Beitrags ist die Bereitstellung schneller Berechnungsmethoden zur Unterstützung des Schaltingenieurs in der zentralen Netzleitstelle bei der Suche nach Abhilfemaßnahmen zur Beseitigung unzulässiger Betriebszustände. Zur Korrektur unzulässiger Spannungs-Blindleistungszustände ist ein ereignisorientiertes Netzsegmentierungskonzept entwickelt worden, das auf einer anforderungsspezifischen Steuergrößenselektion basiert. Bei diesem Verfahren wird die Eigenschaft ausgenutzt, daß wegen des begrenzten topologischen Einflußbereichs des Schaltens von Kompensationseinrichtungen sowie Stufens von Transformatoren nur in der näheren topologischen Umgebung von Unzulässigkeitsstellen installierte Eingriffsmittel zur Zustandskorrektur geeignet sind. Zweigschaltmaßnahmen zur Entlastung überlasteter Betriebsmittel verlangen wegen der stark nichtlinearen Eigenschaften eine von den übrigen Eingriffsmöglichkeiten getrennte mathematische Behandlung. So wird ein Näherungsverfahren zur Abschätzung der entlastenden Wirkung von Topologieänderungen vorgestellt, das auf einer Analyse der durch Zweigschaltungen verursachten Impedanzmatrizenänderungen beruht.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 199 (1963), S. 465-467 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] ZYMOSAN, an insoluble lipoprotein-polysaccharide derived from the cell wall of yeast cells, inactivates the third component of complement1,, produces hyper -plasia and hyperfunction of the reticuloendothelial system3-7. Furthermore, it increases the resistance of mice towards bacterial infections8 ...
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Nuclear Physics, Section A 130 (1969), S. 545-562 
    ISSN: 0375-9474
    Keywords: Radioactivity
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Nuclear Physics, Section A 115 (1968), S. 421-434 
    ISSN: 0375-9474
    Keywords: Radioactivity
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Chemical Physics Letters 14 (1972), S. 528-532 
    ISSN: 0009-2614
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 37 (1989), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: DEKORP 2-S is the first profile carried out in the German continental reflection seismic programme. Besides numerous reflections in the lower crust, the seismic section is characterized by strongly curved events that are interpreted as diffractions. These diffractions occur as clusters, mainly in two areas of the profile: the Dinkelsbühl and the Spessart area. This paper deals with the Dinkelsbühl diffractions where three-dimensional control is available. The control is provided by two additional profiles P-1 and Q-40 which run parallel and perpendicular to the main line, DEKORP 2-S. The type and the location of the diffractors are determined by traveltime-modelling using crustal velocity functions derived from in-line wide-angle observations. A model with inclined line diffractors provides the best fit to the data for all three profiles. Projections of these line diffractors to the surface show that they are aligned parallel to the strike direction of the Variscides. This suggests that the diffractions are associated with the suture zone between the Saxothuringian and Moldanubian geological provinces.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 33 (1985), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: Four methods for the determination of Q in marine sediments are compared: two traditional methods, i.e. the risetime and the spectral ratio method, and two newly established ones, the spectrum modeling and the wavelet modeling method. In the latter one Q and the reflection time T are determined simultaneously, which gives a much better accuracy for T than reading it from the seismogram. The risetime and the spectral ratio methods are used for obtaining Q directly from the data. The principle of the modeling methods is to calculate the effect of absorption and dispersion on a reference wavelet or its spectrum for various values of Q, and the best fit between the observed and the calculated data leads to the optimum result. Numerical tests on synthetic data show that a precision of more than 25% for data containing noise or superposed arrivals can hardly be achieved; in any case, wavelet modeling is the superior method. Application to data from a vertical reflection profile in the Baltic Sea yields Q in the range of 15–100 for different layers, which is to be expected in the sedimentary environment of this area.The computations were performed in the Computer Center of Kiel University. The authors thank R. Meissner for his comments on the manuscript.
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 569-573 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have developed and brought into operation a new type of scanning soft x-ray microscope basing on a grazing incidence mirror. A ring shaped ellipsoidal mirror serves as a nonimaging but concentrating optical element to produce a microfocus. The specimen is mechanically scanned, and the image is recorded a pixel at a time. Transmission, total photoelectron yield, photoelectron spectroscopy, fluorescence, and stimulated desorption of ions and neutrals can provide information in the range of photon energies between 20 and 1300 eV. While the smallest spatially resolved structure, limited by the mirror imperfections, has a size of 0.4 μm, the minimum diameter of selected areas necessary for photoelectron microspectroscopy presently is about 4 μm.
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 3513-3519 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The first attempt to combine luminescence spectroscopy with scanning soft x-ray microscopy has been realized in our experiment. A new imaging luminescence spectrometer with a Schwarzschild objective was designed and built with a spectral resolution of 1.3 nm in the energy range of 1.6–6.5 eV for this purpose. Some luminescent ceramics have been investigated by using this spectrometer. A high contrast in luminescence micrographs is achieved due to the confocal arrangement of the Schwarzschild system and the microscope. The spectral and microstructural properties of these ceramics could be determined by means of luminescence microspectroscopy and spectromicroscopy. © 1995 American Institute of Physics.
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 2021-2029 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Optical elements need to be developed at least at the same pace as synchrotron radiation sources of the third generation. We are concerned here with the interrelationship between improved optical instruments and scientific progress. This relationship becomes especially clear in the development of new monochromators with higher resolution and large throughput. The availability of better mirrors and gratings is most important in this respect. Another field is microscopy. We shall be concerned here mainly with scanning microscopy in which the radiation is imaged with mirrors onto a small spot on the sample. The respective imaging with zone plates is the topic of another paper. A spot size of 0.1 μm and better is theoretically feasible with mirrors but it depends on much progress in the manufacturing of aspherical mirrors of high accuracy. We demonstrate mainly from our own results with a spot in the 1 μm range that it is worthwhile to make this effort. © 1995 American Institute of Physics.
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