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  • 1
    Publication Date: 1987-09-04
    Description: The lower continental crust is one of the least known variables in the crust-mantle evolutionary equation. In order to study the nature and compositional heterogeneity of the lower crust, more than 20 inclusions of lower crustal granulites in volcanic rocks from the McMurdo Sound region of Antarctica were analyzed for strontium and oxygen isotopes. These inclusions were erupted from volcanic centers covering an area of 12,000 square kilometers. Along with results from analyses of major and trace elements, the isotopic data reveal a profound discontinuity in the composition and probably the age of the lower crust that coincides with the boundary between the Transantarctic Mountains and the Ross Embayment. Although this topographic boundary between East and West Antarctica is largely a Cenozoic development, which apparently reflects a simple subvertical faulting relationship due to crustal rifting, the isotopic differences in the lower crust across the boundary suggest that the current faulting and rifting may coincide with an older crustal suture, the age of which is uncertain.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kalamarides, R I -- Berg, J H -- Hank, R A -- New York, N.Y. -- Science. 1987 Sep 4;237(4819):1192-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17801643" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 2
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A description is given of the construction and operating procedure of a parallel-plate apparatus for the measurement of the thermal conductivity coefficient of fluids. This instrument can be operated at pressures up to 150 MPa and at temperatures down to 77 K. The use of platinum resistance temperature sensors allows measurements with temperature differences between upper and lower plate as small as 1 mK, which together with the small plate separation of 155 μm, makes the instrument suitable for both the normal fluid region as well as for the region very close to the critical point. The complete working equations for the instrument are presented and evaluated.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 321 (1986), S. 200-201 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] RECENT work on chemotaxis in bacteria (Escherichia coli and Salmonella typhi-murium) has focused on transducers, a set of membrane proteins that process information about changes in concentration of various sugars and amino acids. Cells lacking any one of these proteins are defective in taxis for ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 1104-1113 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A construction method for determining the domain structure in ideally soft-ferromagnetic cylindrical objects with plane-parallel top and bottom surfaces of arbitrary shape is presented. The self-consistent theory is confined to two-dimensional solenoidal dipole distributions in which the dipoles are parallel to the top and bottom surfaces. It is proved that the basic domain structure is uniquely defined in simply connected objects, while an extra criterion has to be added in order to guarantee the uniqueness in the multiply connected ones. The treatment is based on differential geometrical principles. The object edge is partitioned into segments, in which each segment is situated in between two adjacent edge points where the radii of curvature of convex edge segments are locally minimal. To each edge segment, a region is attributed, in which M is uniquely specified by the course of M along that edge segment. In the cross section of regions corresponding to different edge segments, domain walls provide an adequate separation of the dipole distribution imposed by these segments. The extremities of these domain walls are found in the singular points of the evolute corresponding to the extremities of the edge segments and in the points where a number of walls meet. It is proved that the basic domain structure is the locus of centers of all circles inside the object that touch the object edge at at least two points. A number of experimentally observed basic structures are given, and the relevance of the definition of basic structures in multiply connected objects is examined. OFF
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 2168-2173 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The basic concepts of a self-consistent domain theory for the class of ideal soft ferromagnetic media is unfolded. The treatment is based on micromagnetic equilibrium and stability equations which are simplified by removing the contributions due to the intrinsic anisotropy and the spatial variation term in the exchange energy density. Only the solenoidal magnetization distributions in thin film objects are investigated. This limitation makes confinement to two-dimensional dipole distributions possible. Cauchy's method of characteristics is employed to derive dipole distributions that satisfy the relation ∇⋅M=0, where M is the magnetization, and the constitutive equation. It is proved that the characteristic base curves are straight lines perpendicular to the magnetization vector. In an ellipse, four different characteristic base curves that do not coincide intersect at one single point in certain regions, thus generating ambiguities in the magnetization direction. It is demonstrated that these ambiguities originate in the incompatibility of the magnetization distribution that is imposed by the various segments of the edge of the ellipse. Based on differential geometrical principles, a partitioning of the edge into segments is introduced, and along with it two adjoining regions in which the magnetization direction is uniquely determined are defined. It is proved that a domain wall is required in the cross section of both regions to accomplish a dipole configuration in stable equilibrium. Experimental confirmation is given by means of the ferrofluid pattern of a 3500-A(ring)-thick Permalloy layer with elliptical geometry.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1572-9567
    Keywords: critical region ; ethane ; thermal conductivity ; thermal diffusivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The thermal conductivity of ethane in the critical region has been measured isochorically at densities up to 1.76 times the critical density and at temperatures down to 0.13 K above the critical temperature. The measurements were performed with a thermal conductivity apparatus based on the parallelplate method. The experimental accuracy was 0.5 to 5%, depending on the distance to the critical point. The experimental results agree well with a recently developed crossover theory for the thermal diffusivity of fluids in the critical region.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 4330-4332 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A method for constructing three-dimensional solenoidal magnetization distributions, with invariant magnitude of m, in arbitrarily shaped objects is presented. The formalism harks back to the theory developed by van den Berg for two-dimensional m distributions. The space within a general object Ω is partitioned into i subspaces Ωi, described by a family of surfaces to which the magnetization is tangent. A characteristic equation which defines the course of m at each of the surfaces is derived. A boundary condition for m arises naturally, or can be chosen to determine m at the surface. Within the above framework an infinite number of solutions are generated that, in general, exhibit singularities. Special attention, also from the topological point of view, is paid to the m distributions having point defects only.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The self-consistent domain theory, based on micromagnetic principles, is further developed in order to incorporate all possible solenoidal two-dimensional magnetization distributions in plane-parallel thin-film objects with arbitrary lateral shape. A decomposition of the object into a number of disjunct plane-parallel subregions that completely cover the object's area is put forward. In each subregion, a solenoidal M distribution is defined with the M vector parallel to the subregion's boundary, so that the M distributions in adjacent subregions properly link either via a continuous transition, or via a 180° wall at the intermediate boundary. Two types of subregions are distinguished; namely, the simple connected regions and the so-called parallel regions, being a special type of multiple connected region. In the first category, the basic structures as defined in the preceding paper on this subject are present. The parallel regions are closed ringlike configurations that are built of simpler units—the parallel segments. A parallel segment is a region bounded by two orthogonal trajectories of the same set of straight lines, while two of these straight lines close the segment at either end. No points of intersection of members of this family of lines are found inside the segment. In a specific parallel region, the distance between the orthogonal trajectories is the same for all segments. Adjacent segments in a parallel region are separated by a domain wall which is the locus of centers inside the cross section of the segments of circles that touch at corresponding orthogonal edges of both of the segments involved. A systematic procedure is developed for constructing the parallel subregions, and it is shown that, with this, all possible two-dimensional solenoidal M distributions can be recovered.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 4194-4199 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A self-consistent domain theory, based on micromagnetic principles, is unfolded for two-dimensional solenoidal M distributions present in ideally soft-magnetic plane-parallel thin-film objects at zero external field and in the absence of conduction currents. Two types of domain configurations are distinguished: the basic structures in simply connected regions and the parallel configurations in special types of multiply connected regions—the parallel regions. A decomposition of the objects's area into disjunct subregions, either simply connected or of the parallel type, whose union completely covers the object, is put forward. A procedure for constructing all feasible parallel regions is presented. In each region, the appropriate solenoidal M distribution is specified with which M is taken parallel to the subregion's boundary. Thus, all the domain structures possible in thin-film objects with arbitrary lateral shapes can be constructed. Experimental examples are provided.
    Type of Medium: Electronic Resource
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