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  • 1
    Electronic Resource
    Electronic Resource
    The correlation of the magnetic properties and the magnetocaloric effect in (Gd1−xErx)NiAl alloys (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 5677-5685 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A study of the magnetic properties of several (Gd1−xErx)NiAl alloys (where x=0, 0.30, 0.40, 0.46, 0.50, 0.55, 0.60, 0.80, and 1.00) was undertaken using both ac and dc magnetic and heat capacity measurements in an attempt to understand the table-like magnetocaloric effect previously observed in (Gd0.54Er0.46)NiAl. Results indicate the presence of both antiferromagnetic and ferromagnetic ordering processes in all alloys containing Gd. For ErNiAl, a metamagnetic transition from an antiferromagnetic ground state was observed. Within each alloy, several magnetic transitions occur over a temperature range from 10 K [in (Gd0.20Er0.80)NiAl] up to 35 K (in GdNiAl), with all but the lowest temperature transition shifting to higher temperatures with increasing Gd content. The change in magnetic entropy (ΔSmag) induced by a change in field is observed to peak around the Néel temperature for ErNiAl while gradually broadening and shifting toward the Curie temperature as the Gd content is increased. For Gd-rich alloys, a significant contribution to ΔSmag is observed at both the low and high temperature transitions, resulting in a rounded, skewed caret-like temperature profile of the magnetocaloric effect. Factors, which are believed to contribute to this effect, include the presence and temperature spacing of multiple zero-field transitions, which most likely result from competing anisotropy and exchange interactions within a frustrated hexagonal spin lattice. This leads to broad peaks in the magnetic heat capacity that span several transition temperatures, providing for a substantial ΔSmag over an extended temperature range. This characteristic is desired for application to magnetic refrigeration, where certain thermodynamic cycles (e.g., Ericsson cycle) require specific temperature profiles of the magnetocaloric effect in refrigerant materials (e.g., a constant change in magnetic entropy as a function of temperature within the region of cooling). In general, the best materials are those which supply the maximum amount of cooling over the widest temperature range. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368830
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  • 2
    Electronic Resource
    Electronic Resource
    Triangularizing input-output matrices and the structure of production
    Amsterdam : Elsevier
    European Economic Review 2 (1971), S. 493-522 
    Details
    ISSN: 0014-2921
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0014-2921(71)90024-9
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  • 3
    Electronic Resource
    Electronic Resource
    Triangularizing input-output matrices and the structure of production
    Amsterdam : Elsevier
    European Economic Review 1 (1970), S. 482-511 
    Details
    ISSN: 0014-2921
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Economics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0014-2921(70)90002-4
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  • 4
    Electronic Resource
    Electronic Resource
    Triangularizing input-output matrices and the structure of production
    Amsterdam : Elsevier
    European Economic Review 11 (1971), S. 493-522 
    Details
    ISSN: 0014-2921
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Economics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0014-2921(71)90004-3
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  • 5
    Electronic Resource
    Electronic Resource
    On the RAS-algorithm (1979)
    Springer
    Computing 23 (1979), S. 189-198 
    Details
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung SeiA eine reelle (m, n) Matrix undu, v positive Vektoren. Das nichtnegative Matrixproblem besteht nun in der Aufgabe, eine nichtnegative (m, n) Matrix zu bestimmen, so daßB=diag(x) A diag (y) für Vektorenx ∈ ℝ m undy ∈ ℝ n gilt undu i (v j )i=1, ...,m (j=1,...,n) die Zeilen- und Spaltensummen vonB darstellen. Eine Lösungsmethode (RAS-Verfahren) wurde von Bacharach [1] vorgeschlagen. Ein wesentlicher Nachteil dieses Algorithmus ist die Verlangsamung der Konvergenzgeschwindigkeit durch Rundungsfehler. Hier schlagen wir einen modifizierten RAS-Algorithmus vor, der zusammen mit anderen Verbesserungen diesen Nachteil überwindet.
    Notes: Abstract Given a nonnegative real (m, n) matrixA and positive vectorsu, v, then the biproportional constrained matrix problem is to find a nonnegative (m, n) matrixB such thatB=diag (x) A diag (y) holds for some vectorsx ∈ ℝ m andy ∈ ℝ n and the row (column) sums ofB equalu i (v j )i=1,...,m(j=1,..., n). A solution procedure (called the RAS-method) was proposed by Bacharach [1] to solve this problem. The main disadvantage of this algorithm is, that round-off errors slow down the convergence. Here we present a modified RAS-method which together with several other improvements overcomes this disadvantage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02252097
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  • 6
    Electronic Resource
    Electronic Resource
    Routing in VLSI-layout (1991)
    Springer
    Acta mathematicae applicatae sinica 7 (1991), S. 53-66 
    Details
    ISSN: 1618-3932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract This paper reports on algorithmic approaches for the routing problem of VLSI-logic-chips using combinatorial optimization techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02080203
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  • 7
    Electronic Resource
    Electronic Resource
    Estimating matrices (1981)
    Springer
    Metrika 28 (1981), S. 273-286 
    Details
    ISSN: 1435-926X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Assume that there is an unknown nonnegative (m, n) matrixB which represents the input-output relations of some economy. Given the row and column sums ofB, an approximationA ofB and some information about the relation ofA andB then the input-output estimating problem is to find a matrixX which has the same row and column sums asB and which is a “good” estimate for the actual but unknown input-output matrixB. Here we are going to clarify the different meanings of “good” in the literature and especially develop primal and dual estimating problems. Additionally we present several efficient algorithms solving the estimating problem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01902901
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  • 8
    Electronic Resource
    Electronic Resource
    Zwei Algorithmen zur Lösung eines komplexen Reihenfolgeproblems (1968)
    Springer
    Mathematical methods of operations research 12 (1968), S. 217-231 
    Details
    ISSN: 1432-5217
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Description / Table of Contents: Summary On the ordering of input-output matrices we use some criteria which are more complex than the order conditions of classical sequencing problems (e. g.Traveling-Salesman-Problem). Basing on the papers ofHelmstädter we will give a mathematical formulation of this sequencing problem and two algorithms solving them. One procedure is a lexicographic searching algorithm, the other one a modification of the well knownJacobi-method which calculates the eigenvalues ofHermiteian matrices.
    Notes: Zusammenfassung Bei der Ordnung von Input-Output-Matrizen treten Kriterien auf, die wesentlich komplexer sind als die Ordnungsbedingungen bei klassischen Reihenfolgeproblemen (z. B.Traveling-Salesman-Problem). Ausgehend von den Arbeiten vonHelmstädter werden im folgenden die mathematische Formulierung eines solchen Reihenfolgeproblems sowie zwei Algorithmen zu dessen Lösung angegeben. Ein Verfahren ist ein lexikographischer Suchalgorithmus, das andere eine Modifikation des bekanntenJacobi-Verfahrens zur Berechnung von EigenwertenHermitescher Matrizen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01918332
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  • 9
    Electronic Resource
    Electronic Resource
    Relations between subclasses of greedoids (1985)
    Springer
    Mathematical methods of operations research 29 (1985), S. 249-267 
    Details
    ISSN: 1432-5217
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Description / Table of Contents: Zusammenfassung In früheren Arbeiten wurden viele verschiedene Klassen und Konstruktionen für Greedoide eingeführt und studiert. In dieser Arbeit werden alle bekannten Inklusionsbeziehungen zwischen Unterklassen von Greedoiden dokumentiert. Es wird gezeigt, daß alle Inklusionsbeziehungen echt und alle Unterklassen mit einer Ausnahme tatsächlich verschieden sind.
    Notes: Abstract In previous papers many different classes and constructions of greedoids have been defined and studied. This paper documents inclusion relations among all subclasses of greedoids which are known so far. It will be shown that all inclusion relations are proper and that all but one subclasses of interval greedoids are distinct.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01918757
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  • 10
    Electronic Resource
    Electronic Resource
    Buchbesprechungen (1978)
    Springer
    Mathematical methods of operations research 22 (1978), S. 244-248 
    Details
    ISSN: 1432-5217
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01917667
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