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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 6477-6493 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In order to address the problem of three-body interactions in gas–surface scattering, we considered the collision of a He atom with the (0001) surface of graphite coated by a monolayer of Xe. To eliminate the uncertainties connected with errors in the two-body He–Xe interaction, we determined the latter by crossed-beam differential collision cross-section measurements performed at two energies (67.2 and 22.35 meV). These scattering data together with room-temperature bulk diffusion data are then fitted with a Hartree–Fock–dispersion–type function to yield an interaction potential that explains most of the properties of this system within the experimental errors and represents an improvement on previously published He–Xe potentials. Helium diffraction measurements are then carried out from the Xe overlayer and the dependence of the specular intensity from the angle of incidence is carefully determined. Further, a He–surface potential is constructed by adding together the following terms: (1) the He–Xe pairwise sum, (2) the long-range He–(0001)C interaction, (3) the three-body contribution generated by the Axilrod–Teller–Muto term, (4) the so-called surface-mediated three-body interaction He–Xe–(0001)C first considered by A. D. McLachlan [Mol. Phys. 7, 381 (1964)], and finally (5) a small correction which is meant to take into account the nonstationary nature of the surface. Using this potential, well-converged close-coupling scattering calculations are carried out, and their results compared with the data. In general, good agreement is obtained. The agreement can, however, be improved by (a) an increase of about 30% in the contribution of three-body forces, (b) the lowering of the He–graphite long-range attraction coefficient by about 15%, or (c) a reduction of the two-body interaction well depth of 1.6% (the experimental error) together with any combination of the factors under (a) and (b) reduced by an adequate amount. Elimination of the contribution of the graphite surface by studying Xe multilayers is hindered by the uncertainties in the "thermal correction'' [point (5) above] which, due to the multilayer increased "softness,'' becomes an appreciable source of uncertainty.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 28 (1987), S. 1844-1847 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: It is shown that Einstein's equations are always linearization stable around any finite region of space-time. Let (Ω,g0ab ) be any region of space-time, admitting a compact Cauchy surface with nonempty smooth boundary, and with g0ab a sufficiently smooth solution of the vacuum Einstein equation. It is shown that for any solution g1ab of the linearized equation and any open region U⊆Ω, there exists a smooth one-parameter family gλab of solutions on U such that (gλab||λ=0 =g0ab ) ||U and ((d/dλ)gλab =g1ab )||U. By using a result of Choquet-Bruhat and York [The Cauchy Problem, General Relativity and Gravitation, edited by A. Held (Plenum, New York, 1980), Vol. 1] asserting the smoothness of the map that sends initial data into solutions of Einstein's evolution equations the proof of the above theorem is reduced to the proof of a similar theorem for Einstein's constraint equations. The proof of this latter theorem involves the use of the implicit function theorem in Hilbert spaces. This local result on linearization stability asserts, in contrast to the general global case, that linearization about any vacuum solution is locally physically meaningful.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 187 (1960), S. 790-790 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] With reference to the increasing importance of the cellulose ion exchangers, for example, for fractionation of hsemagglutinating agents1"3, it seems to be useful to know, and to exclude, this hsemagglutinin. The dialytic behaviour of the non-specific hsemag-glutinin from DEAE-cellulose indicates a ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 199 (1963), S. 504-504 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] During the experiments recorded here an aqueous solution of uracil dimer (120 µg/ml.) was irradiated with 100 kr. electrons of 34 MeV at room temperature. After exposure to -rays 30 per cent of the radioactivity of the uracil labelled with carbon-14 were shown to be situated in monomer ...
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1436-6304
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    OR spectrum 11 (1989), S. 191-195 
    ISSN: 1436-6304
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Description / Table of Contents: Summary The technique of designing and constructing simulation models is difficult and requires a lot of knowledge and experience. In general, users of simulation models don't have this expert knowledge. Up to now, it has not been possible to incorporate the expert knowledge necessary for the overall modelling within an expert system which would then in turn make the techniques accessible to the inexperienced user. In general, the close cooperation among experts in the fields of application and simulation techniques remains — for the time being — the only guarantee for successfully scrutinizing a model study. It is, however, possible to combine expert systems and simulation models when using carefully chosen, closely defined fields of application. It is here that an important area of interest and study lies. There are three conceivable alternatives: 1. To provide a simulation model with an intelligent environment which supports the user in constructing as well as evaluating the results made. 2. An expert system contains a simulation model as a possible component. If the expert system needs information that is not directly available, a simulation model is accessed which in turn sends the necessary data back to the expert system. 3. A simulation model contains an expert system as a component. In this case, the model has specific strategies at its disposal that are to be taken into consideration. If the model reaches a point where decisions have to be made, the simulation model turns to the expert system in order to receive information on relevant decisions. These relevant decisions are then used to determine the further course of the model. All three alternatives assume that the expert system as well as the simulation system have an open architecture. The open architecture is a prerequisite for the possibility of coupling the two. Up to now, this requirement has rarely been achieved.
    Notes: Zusammenfassung Der Entwurf und der Aufbau von Simulationsmodellen ist eine schwierige Technik, die sehr viel Wissen und Erfahrung voraussetzt. Die Anwender von Simulationsmodellen verfügen in der Regel über dieses Expertenwissen nicht. Bisher ist es nicht möglich, das für die Modellierung insgesamt erforderliche Expertenwissen in ein Expertensystem zu inkorporieren um es auf diese Weise dem in der Simulationstechnik unerfahrenen Anwender zugänglich zu machen. Im allgemeinen bleibt die enge Zusammenarbeit zwischen Fachleuten auf dem Anwendungsgebiet und der Simulationstechnik bis auf weiteres die einzige Garantie für eine erfolgreiche Modelluntersuchung. In ausgewählten, sehr engen abgegrenzten Anwendungsgebieten ist es jedoch möglich, Expertensysteme und Simulationsmodelle zu vereinen. Hier entwickelt sich ein bedeutendes Arbeits- und Aufgabenfeld. Es sind drei Alternativen vorstellbar: 1. Ein Simulationsmodell erhält eine intelligente Umgebung, die den Anwender beim Modellaufbau und bei der Ergebnisauswertung unterstützt. 2. Ein Expertensystem enthält als eine mögliche Komponente ein Simulationsmodell. Falls das Expertensystem Informationen benötigt, die nicht direkt verfügbar sind, wird ein Simulationsmodell angestoßen, das die erforderlichen Daten an das Expertensystem zurückliefert. 3. Ein Simulationsmodell enthält als Komponente ein Expertensystem. In diesem Fall enthält das Modell Strategien, die zu berücksichtigen sind. Falls das Modell an einen Punkt kommt, an dem Entscheidungen getroffen werden müssen, wendet sich das Simulationsmodell an das Expertensystem und läßt sich die maßgebenden, den weiteren Modellablauf bestimmenden Entscheidungen mitteilen. Alle drei Alternativen verlangen vom Expertensystem und dem Simulationssystem eine offene Architektur. Die offene Architektur ist Voraussetzung dafür, daß sich beide Systeme koppeln lassen. Diese Forderung ist bisher kaum erfüllt.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    International journal of legal medicine 50 (1960), S. 34-53 
    ISSN: 1437-1596
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 50 (1963), S. 473-473 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 9
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    Unknown
    Berlin : Periodicals Archive Online (PAO)
    Deutsche Zeitschrift für Philosophie. 37:3 (1989) 257 
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 5 (1964), S. 90-100 
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Notes: Zusammenfassung Nach einleitender Besprechung der chemischen und ernährungsphysiologischen Eigenschaften von Fischölen wird über Untersuchungen über die scheinbare Ausnützung von Sojaöl, unverändertem und anoxydiertem Rotbarschöl (POZ ∼ 50) berichtet, die ergaben, da\ das unveränderte Fischöl eine niedrigere scheinbare Ausnützung aufweist. Die Höhe der Ausnützung ändert sich mit der Versuchsdauer. Bei der erstmaligen Verabreichung von 1-14C-markierter Palmitinsäure im Gemisch mit den 3 ölsorten besteht eine weitgehende übereinstimmung der Aktivitätsverteilung im Stoffwechsel. Lediglich eine Tendenz zur vermehrten Resorption und Oxydation der Palmitinsäure scheint sich darzutun, wenn man sie mit anoxydiertem Rotbarschöl verabreicht gegenüber der Zuführung mit nativem öl.
    Type of Medium: Electronic Resource
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