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  • 1985-1989  (8)
  • 1970-1974  (2)
  • 1987  (8)
  • 1973  (2)
Material
Years
  • 1985-1989  (8)
  • 1970-1974  (2)
Year
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 2803-2806 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The incorporation of the lanthanide element erbium in GaAs during growth by liquid-phase epitaxy is investigated by low-temperature photoluminescence measurements. After an anneal of the epitaxial layers at 850 °C, a characteristic Er-associated optical transition appears at a wavelength of ∼1.55 μm, however, no erbium-related photoluminescence signal is found in the as-grown GaAs:Er layers. The Zeeman splitting of the new photoluminescence lines reveals a cubic symmetry of the optically active Er complex. Successive mechanical polishing and annealing of the layers provides evidence for the incorporation of Er within the layer as an optically inactive Er complex, which is activated only at the surface by thermal annealing.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 91 (1987), S. 3187-3190 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 43 (1987), S. 1022-1025 
    ISSN: 1420-9071
    Keywords: Calcium ; magnesium ; nematocysts ; Hydra ; Cnidaria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An X-ray spectral analysis (EDAX) of isolated undischarged nematocysts of various cnidarians (Hydrozoa, Scyphozoa, Anthozoa) revealed the presence of extremely high concentrations of divalent cations. InHydra nematocysts both Ca2+ (conc. 0.36 μmole/mg dry cysts) and Mg2+ (conc. 0.80 μmole/mg dry cysts) ions add up to a total in situ concentration of 0.5 to 1.0 M. More than 85% of the cations, which are believed to be involved in cyst discharge, are contained in the soluble fraction of the cysts, where they must be bound to high molecular weight molecules.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Electrical engineering 55 (1973), S. 252-262 
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The current/time and voltage/time functions are derived for the principal and auxiliary arms of a self-commutated inverter as well as for its commutating capacitor. This is done at the example of the directly commutated (parallel type) inverter. The results are given as formulac as well as in figures for the different in tervals during the commutating process. Formulac for the electrical design of the components of the commutating circuit are derived.
    Notes: Übersicht Anhand des Beispiels der direkten Kommutierung werden Strom-und Spannungsverläufe in den Haupt-und Hilfszweigen des selbstgeführten Wechselrichters sowie im Kommutierungskondensator abgeleitet. Das Ergebnis wird in Formeln und Bildern für die einzelnen Zeitabschnitte des Kommutierungsvorgangs angegeben. Daraus werden Hinweise für die Bemessung des Kommutierungskreises abgeleict.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Electrical engineering 70 (1987), S. 83-90 
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents Analytical terms to determine the diversion of current into a twin conductor and a parallel connected co-axial cable are set up, whereat the twin conductor is originally fed by sinusoidal alternating current having an amplitudeI and the radian frequency while core and sheath of the coaxial cable are connected each parallel to one of the phases of the twin conductor. — From the beginning skin effect occuring in the coaxial cable is completely considered and later on — according to the dimensions of the arrangement — approximated, while skin effect occuring in the twin conductor is neglected. — Moreover, an equivalent circuit is given having impedances that can be determined from the dimensions of the arrangement and from the skin depth.
    Notes: Übersicht Aufgestellt werden analytische Beziehungen für die Stromaufteilung zwischen einer Doppelleitung, die im ursprünglichen Zustand vom sinusförmigen Wechselstrom der konstanten AmplitudeI und der Kreisfrequenz ω durchflossen wird, und einem die Doppelleitung entlastenden Koaxialkabel, dessen Kern und Manted mit jeweils einem Strang der Doppelleitung parallelgeschaltet ist. Bei der Berechnung wird der Skineffekt im Koaxialkabel zunächst voll und später aufgrund der Abmessungsverhältnisse nur näherungsweise berücksichtigt, während der Skineffekt in den beiden Strängen der Doppelleitung vernachlässigt wird. Ferner wird ein Ersatzschaltbild angegeben, dessen Impedanzen aus den geometrischen Abmessungen des Systems und der Eindringtiefe bestimmt werden.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 113 (1987), S. 8-14 
    ISSN: 1432-1335
    Keywords: Urinary bladder ; Stimulation of urothelial proliferation ; Partial cystectomy ; Cyclophosphamide ; Synchronization ; Hydroxyurea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the present experiments an attempt was made to synchronize urothelial proliferation in the urinary bladder of rats stimulated by either a partial cystectomy (one-third resection) or a single i.p. administration (100 mg/kg) of CP. To temporarily inhibit DNA synthesis HU was given intraperitoneally in multiple fractionated doses (0.1 mg/g each) at hourly intervals during the period of most pronounced proliferative activity between 33 and 55 h after partial cystectomy and between 26 and 44 h after injection of CP. Following partial cystectomy the 3H-TdR index rapidly increased after termination of the HU administration reaching peak values of 54% and 56% at 6 and 8 h, respectively. Thereafter, there was a sharp decline of the percentage of DNA synthesizing cells within 2 h to 24% at 10 h. Then 16 h after removal of the HU block the 3H-TdR index amounted to 15%. At 20 h the labeling increased again to 22%, indicating that the initially blocked cells were capable of going through another cell cycle. After 1 week the 3H-TdR index was 2.5% and after 15 days 0.2%. Synchronously with the decrease of DNA synthesis the mitotic index rapidly increased reaching a maximum value of 4.3% at 10 h. The total fraction of 3H-TdR-labeled cells (growth fraction) was 57%. Following administration of CP 3H-TdR incorporation increased steeply after the last injection of HU and at 6 h a maximum value of 50% was obtained. Subsequently, the 3H-TdR index gradually decreased to 11% after 12 h. At 8, 15, and 30 days labeling indices of 1.9%, 0.5%, and 0.3% were determined. The mitotic index was highest with 0.21–0.22% between 12 and 16 h after removal of the HU block. The growth fraction amounted to 53%. The results reported here show a satisfactory degree of synchrony of stimulated urothelial proliferation obtained by multiple fractionated doses of HU. In particular the cystectomy model will be useful for testing possible cell cycle specifity of urothelial carcinogenesis.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 258 (1973), S. 277-283 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The effect of concentration on laser threshold is examined theoretically and experimentally for Rhodamin B and Rhodamin 6G. Laser action is obtained in the region from 1 · 10−6 mol to 2.5 · 10−1 mol. Lasing in organic dye solutions which are excited by a pulslaser is possible in a broad concentration range. For high concentrations laser action is limited by fluorescence quenching and increasing losses (diffraction, thermal effects, and bleaching). For low concentrations the limit is given by the losses of the used experimental set-up. In the present work the influence of the concentration on the exciting intensity at laserthreshold is examined for Rhodamin B and Rhodamin 6G solutions.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-4978
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DNA-fragments from the region of the long arm of human chromosme 7 to which the CF-locus has been mapped recently were isolated by microdissection and microcloning. We developed a new fixation procedure resulting in inserts of 1.0–7.0 kb in length with a mean value of 2.9 kb. Regional mapping of three clones on 7q was carried out by the use of different hybrid cell lines containing fragments of human chromosome 7.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Rock mechanics and rock engineering 20 (1987), S. 1-38 
    ISSN: 1434-453X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Notes: Summary The planned network for the Munich subway system has a total length of about 100 km with 106 stations. At present 46 km of subway and 50 stations are in operation. A further 17 km and 18 stations are under construction. The annual volume of construction work has reached a total of approximately 300 million DM. A stretch of 21 km has been constructed using shotcrete support. A part of this work still has to be completed. In the paper, the method of tunnelling using shotcrete is presented in its total context, whereby the important aspects are discussed under the following themes: Overview of the construction project as a whole with reference to finance, permitting procedures and realisation. Cut-and-cover and mining techniques. The construction of single-track tunnel and the excavation of large cross-sections, switches and sidings, different geotechnical procedures in dealing with water, especially compressed air operations. Experiences with contract practices, construction, questions of safety, quality and cost control, damage analysis and comparison of costs.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 66 (1987), S. 41-54 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Low-field magnetic screening and breakdown fields have been measured in thick proximity-induced superconducting copper by means of dc magnetization and ac susceptibility in the temperature range 10 to 0.005 K. From the thickness and temperature dependence of the breakdown field the Cooper pair penetration depth in copper is obtained. This value isK N −1 =0.6/T μm, withT in kelvins. No saturation effects were observed in the screening length ρ, the breakdown fieldH b, or the supercooled fieldH sc down to the lowest temperatures.
    Type of Medium: Electronic Resource
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