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  • 1
    Electronic Resource
    Electronic Resource
    Microwave measurements and modelling of the permittivity of tropical vegetation samples (1981)
    Springer
    Applied physics 25 (1981), S. 351-355 
    Details
    ISSN: 1432-0630
    Keywords: 77.20 ; 42.10,06
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Microwave measurements of tropical vegetation samples (grass, casuarina, rubber leaf, rubber wood) at 9.5 GHz as a function of moisture content at 21°C are presented. A comparison is made with results calculated from six models for the permittivity of dielectric mixtures. Of these, only one of the models due to Polder, van Santen, and deLoor is found to give reasonable agreement, particularly for the real part of the permittivity. It is clear that more complex formulations for the permittivity of vegetation are necessary to model its behaviour as a function of moisture content and frequency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00902994
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  • 2
    Electronic Resource
    Electronic Resource
    Copper as an electron trap in GaAs0.6P0.4 (1994)
    Springer
    Applied physics 59 (1994), S. 245-251 
    Details
    ISSN: 1432-0630
    Keywords: 71.00 ; 61.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract An electron trap having an energy level of 0.14 eV from the conduction band edge was found in the bulk of copper-diffused VPE-grown n-GaAs0.6P0.4 by conventional DLTS measurements and by pulse-duration dependent capacitance amplitude measurements. The capture cross section at room temperature is about 1.0×10−21 cm2 and has a weak temperature dependence. These properties are attributed to a non-repulsive center having a capturing mechanism which involves multiphonon emission processes with hardly any lattice relaxation. Evolution of the spatial distributions of the traps with time under junction electric field were studied. The results suggest that the trap is positively charged and has a high diffusivity under electric field. The center can thus be identified as positively charged interstitial copper ion rather than some form of copper complexes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00348227
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  • 3
    Electronic Resource
    Electronic Resource
    Charge-state effects of deep centres in semiconductors on non-radiative capture of carriers by multiphonon processes (1996)
    Springer
    Applied physics 63 (1996), S. 37-43 
    Details
    ISSN: 1432-0630
    Keywords: 71.55 ; 63.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A set of simplified analytical expressions for carrier capture coefficients, including quantatively the charge-dependent effect, have been obtained for easy physical examination and comparison with experiments. The temperature-related charge-state-dependent factorF(T) thus calculated could be used to present more accurately the nature and magnitude of the charge state of a trap centre. The ranges of values ofF(T) valid for attractive, repulsive and neutral centres are also obtained. In addition, we show that the thermal ionization energy for theB centre in GaAs is a function of temperature. The importance of the data of capture cross-section at low temperatures in determining the charge state and characteristic of a deep centre is also manifested. Both the absolute magnitude and the temperature-dependent behaviour of the calculated capture cross-section are well-supported by the very good fits to the experimental electron cross-sections forA andB centres in GaAs reported by Lang [7] and Wang et al. [22] and for Cu centre in Ge reported by Zhdanova and Kalashnikov [23].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01579744
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  • 4
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of coumarin and its 7-hydroxy-metabolites upon intravenous and peroral administration of coumarin in man (1977)
    Springer
    European journal of clinical pharmacology 12 (1977), S. 457-461 
    Details
    ISSN: 1432-1041
    Keywords: Coumarin ; 7-Hydroxycoumarin ; drug disposition ; first-pass effect ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of coumarin (C) upon i.v. and p.o. administration and its metabolites 7-hydroxy-coumarin (7-HC) and 7-hydroxy-coumarin glucuronide (7-HCG) have been studied. Six healthy volunteers were involved in this investigation. Four of the volunteers participated in a crossover study. Coumarin was administered i.v. and p.o. in dose sizes of 0.25 mg/kg and 0.857 mg/kg, respectively. Coumarin is rapidly absorbed p.o., however the availability to systemic circulation is less than 4%. The rest of the dose appears quantitatively as 7-HC and 7-HCG in systemic circulation suggesting an extensive firstpass effect. Coumarin and 7-HCG are best fitted to an open two-compartment model, whereas 7-HC is best fitted to an open one-compartment model. The biological half-life of both C (0.80 vs. 1.02 h) and 7-HCG (1.47 vs. 1.15 h) was not significantly different for the two routes of administration. The large total clearance of C again suggests a first-pass effect; while that of 7-HCG, which is nearly exclusively eliminated into urine, indicates active tubular secretion of the glucuronide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561066
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  • 5
    Electronic Resource
    Electronic Resource
    Enhancement of Optokinetic and Vestibuloocular Responses in the Rabbit by Cholinergic Stimulation of the Flocculus (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 656 (1992), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1992.tb25240.x
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  • 6
    Electronic Resource
    Electronic Resource
    Three-Dimensional Optokinetic Responses in Man and Rabbit: A Comparison between a Frontal and a Lateral Eyed Species (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 656 (1992), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1992.tb25287.x
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  • 7
    Electronic Resource
    Electronic Resource
    Acetylcholine Enhances Optokinetic Modulation of Floccular Purkinje Cells (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 781 (1996), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1996.tb15765.x
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  • 8
    Electronic Resource
    Electronic Resource
    A systematic study on structural and dielectric properties of lead zirconate titanate/(Pb,La)(Zr(1−x)Ti(x))O3 thin films deposited by metallo-organic decomposition technology (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 4283-4290 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Pin-hole free ferroelectric (Pb,La)(Zr1−xTix)O3 thin films with uniform composition have been fabricated using the metallo-organic precursor compounds, which were carefully home synthesized. The structural development, spectroscopic, and dielectric properties of these films have been systematically investigated using atomic force microscopy (AFM), x-ray diffraction, Fourier transform infrared spectroscopy, Raman scattering, and dielectric measurements. It has been found from our experimental results of PZT 40/60 thin films that the overlapping of (h00) and (00l) peaks of these films in x-ray diffraction patterns, mainly due to the small grain sizes in films, makes it very difficult to distinguish individual diffraction peaks and to identify the phases. However, Raman measurements undoubtedly reveal the Raman spectra of these films in the tetragonal phase field, demonstrating that Raman spectroscopy is an effective tool to identify structures, especially in the case of thin films having very small grains. AFM results show that the PZT perovskite structure in films may grow radially by rosettes and that microcracks appear in the three-dimensional AFM pictures at grain boundaries, which may be the cause for easy dielectric breakdown.A striking feature of the AFM observation is that three polycrystalline perovskite regions intersect symmetrically at a point with 120° to each other, and a rosette growth model for the perovskite structure in PZT films is thus proposed to explain this new phenomenon. The excellent ferroelectric properties of these films, such as the high fatigue resistance and low leakage current, are attributed to the high quality of the metallo-organic solutions and to reduce the amount of oxygen vacancies in the films by optimizing the annealing conditions and by doping a suitable amount of La ions to minimize the charge blocking of oxygen vacancy at the interface by Pt electrode. It seems that the rhombohedral PZT films with softer hysteresis loops are suitable for nonvolatile random access memory application. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.361797
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  • 9
    Electronic Resource
    Electronic Resource
    Properties of carbon ion deposited tetrahedral amorphous carbon films as a function of ion energy (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 7234-7240 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ion energy, controlled by the substrate bias, is an important parameter in determining properties of films deposited by the filtered cathodic vacuum arc technique. The substrate bias determines the ion energy distribution of the growth species. The ion energy is varied, while keeping the other deposition conditions constant, in order to study the effect of ion energy on the film properties. The films were characterized by their optical and mechanical parameters using an ellipsometer, surface profilometer, optical spectrometer, and nanoindenter. Electron energy-loss spectroscopy and Raman spectroscopy were used for structural analysis of the films. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.361440
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  • 10
    Electronic Resource
    Electronic Resource
    Tight-binding recursion calculations of step energetics on the GaAs(110) surface (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 107 (1997), S. 5914-5917 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: On the GaAs(110) surface steps perpendicular to the [001] direction may be either arsenic-terminated or gallium-terminated. We compute the energy difference between these steps using a tight-binding recursion method. We find that the arsenic-terminated step is more stable by approximately 0.5 eV. Our results suggest that some recent experimental observations on the shape of islands formed during homoepitaxy on GaAs(110) may be the consequence of an energy-driven rather than a kinetics-driven epitaxial growth. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.475158
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