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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 101 (1979), S. 7079-7080 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 26 (1977), S. 225-230 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract A model is suggested, which — starting with the relatively small hydromechanical selectivity of the basilarmembrane displacement — describes the level dependent frequency selectivity of the ear as measured psychoacoustically. Nonlinear transferfunctions cause the level dependence. The increment in selectivity is produced by differential devises. Even though the system contains marbed nonlinearities, it works like a quasi linear system.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract For an observer in space the intensities and anisotropies of solar cosmic-ray events are governed by the duration and the functional shape of the injection processes near the Sun and by the propagation along the interplanetary magnetic field from the Sun to the observer. We study the influence of four different types of solar injections (Gaussian, exponential, step-function and coronal diffusion), and of a purely diffusive interplanetary propagation, where the diffusion coefficient has a power law dependence on the radial distance from the Sun, κ=Mr β on both the time-intensity and the time-anisotropy profiles at 1 AU. The main results are as follows: A slow quasi-exponential decay of the intensity can be modelled in some cases; all finite injections produce high anisotropies during the main phase of an event; an ‘effective’ solar injection length can be determined from simultaneous inspection of the intensities and anisotropies; the intensities and anisotropies do to first order not depend on the analytic shape of the various injection profiles. The model is applied to the November 18, 1968 solar event as observed by Pioneer 9 in the 7.5–21.5 MeV and 21.5–60 MeV energy channels. We obtain local diffusion coefficients in the range M= (2.5–5) × 1021 cm2 s−1 and injection periods of the order of 10–20 hr. Closer inspection reveals the change of interplanetary propagation conditions during the event.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2013
    Keywords: Reptile Vestibular Neurons ; Vestibular Efferents ; Commissural Inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Field and intracellular potentials were recorded in the vestibular nuclei of the lizard following stimulation of the ipsi-and contralateral vestibular nerves. The field potentials induced by ipsilateral VIIIth nerve stimulation consisted of an early negative or positive-negative wave (presynaptic component) followed by a slow negativity (transsynaptic component). The spatial distribution of the field potential complex closely paralleled the extension of the vestibular nuclei. Mono- and polysynaptic EPSPs were recorded from vestibular neurons after ipsilateral VIIIth nerve stimulation. In some neurons early depolarizations preceded the EPSPs. These potentials may be elicited by electrical transmission. Often spikelike partial responses were superimposed on the EPSPs. It is assumed that these potentials represent dendritic spikes. Contralateral VIIIth nerve stimulation generated disynaptic and polysynaptic IPSPs in some neurons and EPSPs in others. The possible role of commissural inhibition in phylogeny is discussed. In a group of vestibular neurons stimulation of the ipsilateral VIIIth nerve evoked full action potentials with latencies ranging from 0.25–1.1 msec. These potentials are caused by antidromic activation of neurons which send their axons to the labyrinth.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 293 (1979), S. 187-201 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract K-, L andM-shell ionization cross sections have been measured for 23 elements, 12≦Z≦92, after bombardment with relativistic electrons, 15≦E 065MeV, by means of high resolution semiconductor detectors and a recently developed gas-scintillation proportional counter. For constant electron bombarding energyE 0 the ionization cross sections follow a power law dependence,σ∽Z −α, and forE 0=50MeV we deducedα =2.45±0.02 for theK shell andα=3.00 ±0.09 for theL shell. The observedZ dependence exhibits significant systematic deviations from theoretical predictions which exceed the experimental values up to 15 % at lowZ elements for theK shell and on the average about 11% for theL andM shell. The same behaviour of too low experimental values, i.e. an overestimation by the theory, is observed for the energy dependence of the cross sections for all shells. A scaling behaviour describing theZ andE 0 dependence for allK-, L andM-shell data points is observed which also predicts the experimental values by other groups at lower and higher energies correctly. The comparsion of the measuredLΒ/Lα, andLγ/Lα intensity ratios for highZ elements with the values obtained by other groups in the energy range 0.3≦E0≦1,000 MeV exhibits an increase with bombarding energy that cannot merely be explained by the energy dependence of the subshellionization cross sections for theL shell. An attempt to explain this effect with the change of the Coster-Kronig transition probability is described.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Optical and quantum electronics 11 (1979), S. 87-96 
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract In this paper we investigate the possibility of using thick holograms as diffraction gratings. We compare the well-known parameters of the plane diffraction grating such as dispersion, efficiency, resolution, and others, with those for volume holograms. The calculations for the case of volume holograms are based on the theory of coupled waves. Experiments were performed with volume-phase holograms in transmission, stored in dichromated gelatine layers. The investigations show that the volume hologram fulfills two functions simultaneously. It acts as a spectral predecomposer and also as a high-resolving spectral apparatus.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 64 (1979), S. 391-401 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Theoretical considerations lead to a solar cosmic ray diffusion coefficient which varies with heliolongitude in a stream-structured solar wind. By solving numerically the time dependent convection-diffusion equation for the particle transport we investigate the effect of the azimuthal variation of the diffusion coefficient on intensity-time profiles as seen by a stationary observer. Depending on the position of the observer relative to the solar wind stream at the time of flare occurrence, completely different intensity-time profiles will be observed. When the spacecraft is at the time of the flare occurrence right at the leading edge of a solar wind stream, the large mean free path leads to rapid steepening of the initial phase of the intensity profile. The longitudinally decreasing mean free path ∼ 1 day in front of the leading edge will lead to intensity-time profiles similar to long-time injection events if the event occurs before the stationary observer enters the flux tubes with the decreasing diffusion coefficient.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 321 (1979), S. 827-834 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 2-Heterocyclidenamino-1, 3-diaza-trimethincyaninesThe synthesis of 2-[3-methyl-benzthiazol-(1, 3)-inylidene-(2)-amino]- and of substituted 2-[1, 3-dithiolyliden-(2)-amino]-1, 3-diaza-trimethincyanines is described. The heterocyclic imines 1 react with phosgene or thiophosgene to the corresponding ureas 2 and thiureas 3, respectively. Alkylation of 3 to the 2-alkylmercapto-1, 3-diaza-trimethincyanines 4 and subsequent condensation with imine 1 yields the dyes 5. The chemical and spectroscopical data of cyanines 5 are described.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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