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  • 1
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Analytical chemistry 25 (1953), S. 1574-1574 
    ISSN: 1520-6882
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Inorganica Chimica Acta 109 (1985), S. 221-224 
    ISSN: 0020-1693
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Physica B: Physics of Condensed Matter 163 (1990), S. 185-187 
    ISSN: 0921-4526
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Physik
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 5061-5066 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Solid-state interdiffusions at the Ni/GaSb(111) and (001) interfaces were investigated in the temperature range 200–600 °C using 1.8 MeV He+ ion backscattering and channeling and also using x-ray diffraction. The starting point was the experimental determination of the Ni-Ga-Sb phase diagram. The steps of the interaction were the same for GaSb(111) and GaSb(001). Three various phases were observed: the ternary A phase with the Ni2.5GaSb atomic composition, Ni2Ga3, and Ni2Ga0.25Sb1.75, the Ga-rich limit of the substituted NiSb binary compound. All these phases had a hexagonal pseudocubic structure. First, an epitaxial Ni2.5GaSb A phase reacted layer was obtained. This phase was not in thermodynamical equilibrium with GaSb and the final product was a mixture of Ni2Ga3 and Ni2Ga0.25Sb1.75 grains with an average atomic composition equal to Ni1.6GaSb. The metallurgical behavior of the Ni/GaSb contacts was compared to that of the Ni/GaAs and Ni/AlAs contacts. It was concluded that the experimental ternary diagram allowed a correct estimation of the sequence of phase formation in metal/compound semiconductor contact. In contrast, due to major differences in the ternary phase diagrams, the steps of the solid phase interdiffusion cannot be deduced from the results obtained on a priori equivalent contacts.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 44 (1996), S. 0 
    ISSN: 1365-2478
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie , Physik
    Notizen: Electrical conductivity mapping is a prerequisite tool for hydrogeological or environmental studies. Its interpretation still remains qualitative but advantages can be expected from a quantitative approach. However a full 3D interpretation is too laborious a task in comparison with the limited cost and time which are involved in the majority of such field studies. It is then of value to define the situations where lateral variations are sufficiently smooth for a 1D model to describe correctly the underlying features.For slingram conductivity measurements, criteria allowing an approximate 1D inversion are defined: these mainly consist of a limited rate of variation over three times the intercoil spacing.In geological contexts where the weathering has generated a conductive intermediate layer between the underlying sound rock and the soil, this processing can be applied to determine the thickness of the conductive layer from the apparent resistivity map when the other geoelectrical parameters are known. The examples presented illustrate this application.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 54 (2003), S. 0 
    ISSN: 1365-2389
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: There is no simple and general relationship between the thermal conductivity of a soil, λ, and its volumetric water content, θ, because the porosity, n, and the thermal conductivity of the solid fraction, λs, play a major part. Experimental data including measurements of all the variables are scarce. Using a numerical modelling approach, we have shown that the microscopic arrangement of water influences the relation between λ and θ. Simulated values for n ranging from 0.4 to 0.6, λs ranging from 2 to 5 W m−1 K−1 and θ from 0.1 to 0.4 can be fitted by a simple linear formula that takes into account n, λs and θ. The results given by this formula and by the quadratic parallel (QP) model widely used in physical property studies are in satisfactory agreement with published data both for saturated rocks and for unsaturated soils. Consequently, the linear formula and the QP model can be used as practical and efficient tools to investigate the effects of water content and porosity on the thermal conductivity of the soil and hence to optimize the design of thermal in situ techniques for monitoring water content.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    European journal of soil science 55 (2004), S. 0 
    ISSN: 1365-2389
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Soil cracks formed by natural processes play a key role in water and gas transfer. Patterns of soil cracks are, however, difficult to characterize. Our aim here is to assess the effectiveness of three-dimensional electrical resistivity surveys in detecting soil crack networks. A three-dimensional electrical survey was carried out by a square array quadripole with Cu–CuSO4 electrodes (electrode spacing of 3 cm). The measurements were made with two orientations (0° and 90°) on a block (26 cm × 30 cm × 40 cm) of soil while it dried for 18 days under controlled conditions. Two indexes, calculated from the apparent resistivity values, were evaluated to detect the degree of soil heterogeneity: (i) an anisotropy index based on the ratio between the apparent resistivity at 0° and that at 90°; and (ii) the angle-array orientation corresponding to the preferential anisotropic orientation (maximum resistivity). The anisotropy index provided information on the presence of cracks and the orientation for crack width 〉 1 mm in the first pseudo-depth (i.e. depth of investigation), while the angle-array orientation provided information on crack extension for the whole pseudo-depth. Information about the presence, position, orientation and extension of cracks can be obtained from an analysis of apparent resistivity obtained by a three-dimensional electrical survey. Such direct analysis will help the resistivity inversion to detect the crack network.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 2129-2136 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The solid-state interactions at the Ni/(111) and (001) GaAs interfaces were investigated in the temperature range 25–600 °C by Rutherford backscattering spectrometry and channeling experiments, x-ray diffractometry, and four-point probe. The samples were prepared by depositing nickel films, 70 nm thick, onto clean (111) and (001) GaAs single-crystal substrates under 5×10−10 Torr vacuum. Then they were annealed for 1 h at increasing temperatures under a flow of forming gas (90% N2-10% H2). The sequence of phase formation was the following: first, a ternary phase at 200 °C, then a mixture of two ternary phases at 250 and 350 °C, and finally from 400 to 580 °C a mixture of a ternary phase and NiAs. This last structure was stable up to 600 °C on (111) GaAs, but at this temperature a further consumption of GaAs led to a mixture of (NiGa+NiAs) onto (001) GaAs. Small differences were observed versus the orientation of the GaAs samples but all the ternary and binary phases exhibited epitaxial arrangements with both the (111) and (001) GaAs substrates. The ternary-phase diagram for the bulk Ni-Ga-As system provides the basis for understanding the sequence of the above results and much of the information in the literature about Ni/GaAs interfacial reactions.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 7613-7619 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Solid-state interactions of Ni thin films on (111) GaAs and (111) AlAs were investigated using transmission electron microscopy. We show that the experimental determination of the Ni-Ga-As and Ni-Al-As ternary phase diagrams, and the accurate determination of the atomic composition and crystalline structure of the various ternary solid solutions are absolutely required to understand the x-ray and electron diffraction patterns, and thus identify the compounds in the reacted layers and explain the different steps of the reactions. For this purpose, we report the results obtained on three typical samples, where hexagonal superstructured ternary phases have been observed.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 31 (1988), S. 2086-2092 
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: In this study the effect of rigid side walls on the onset of solutal convection in the melt is investigated for upward solidification of a binary alloy. The physics is described by the Navier–Stokes equations in the Boussinesq approximation and by the balance of solute, which is coupled with the appropriate boundary conditions. By using a Tau–Chebyshev spectral method the numerical resolution of the perturbed system has been carried out for two alloys: lead–tin, which is the reference in the literature, and lead–thallium, which is currently under study. For both cases the lateral confinement has a stabilizing effect for all the aspect ratios that have been considered.
    Materialart: Digitale Medien
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