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221.
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Prof. Dr. B. Korte Prof. Dr. L. Lovász 《Mathematical Methods of Operations Research》1985,29(7):249-267
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.
Supported by the joint research project Algorithmic Aspects of Combinatorial Optimization of the Hungarian Academy of Sciences (Magyar Tudományos Akadémia) and the German Research Association (Deutsche Forschungsgemeinschaft, SFB 21). Part of this research was done while the first author was visiting the Department of Combinatorics and Optimization, University of Waterloo. 相似文献
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.
Supported by the joint research project Algorithmic Aspects of Combinatorial Optimization of the Hungarian Academy of Sciences (Magyar Tudományos Akadémia) and the German Research Association (Deutsche Forschungsgemeinschaft, SFB 21). Part of this research was done while the first author was visiting the Department of Combinatorics and Optimization, University of Waterloo. 相似文献
224.
Prof. Dr. U. Zimmermann I. S. Schubert Dipl. Math. 《Mathematical Methods of Operations Research》1985,29(5):187-201
We consider the one-parametric linear bottleneck problem min {c (x, t) ¦ x P (t)} where the bottleneck objectivec (x, t):=max {cj (t) ¦ xj>0} is minimized subject to linear constraints, i.e. P(t):={x ¦A (t) ·x=b (t), x0}. All coefficients are assumed to be continuous functions of one real parametert which varies in a real intervalS. A method is developed for constructing a partition ofS into subintervals on which either a basis stays optimal or the problem stays infeasible. Finiteness of the partition is due to certain finiteness assumptions on the zeroes of particular combinations of the coefficient functions. Using a lexicographic refinement of the objective function a characterization of the optimality interval of a fixed basis is derived which is independent on explicit information about other bases.
Zusammenfassung Es werden einparametrische lineare Engpaßprobleme min {c (x, t) ¦x P (t)} betrachtet, wobei die Engpaßzielfunktionc (x, t):=max {cj (t) ¦ xj >0} unter linearen Nebenbedingungen, die durch P(t):={x ¦A (t) ·x=b (t), x0} gegeben sind, minimiert wird. Dabei wird angenommen, daß alle Koeffizienten stetige Funktionen eines reellen Parameterst aus einem IntervallS R sind. Es wird eine Methode entwickelt,S derart in Teilintervalle zu zerlegen, daß entweder eine Basis in solch einem Teilintervall optimal oder das Problem unzulässig bleibt. Die Endlichkeit dieser Partition vonS ergibt sich aus Endlichkeitsvoraussetzungen für die Nullstellen von Funktionen, die sich als gewisse Kombinationen der Koeffizientenfunktionen schreiben lassen. Durch eine lexikographische Verfeinerung der Zielfunktion gelingt es, das Intervall zu charakterisieren, in dem eine feste Basis optimal ist. Diese Charakterisierung ist unabhängig von expliziten Informationen über andere Basen.相似文献
225.
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227.
G. Münzenberg S. Hofmann H. Folger F. P. Heßberger J. Keller K. Poppensieker B. Quint W. Reisdorf K. H. Schmidt H. J. Schött P. Armbruster M. E. Leino R. Hingmann 《Zeitschrift für Physik A Hadrons and Nuclei》1985,322(2):227-235
In irradiations of207Pb and208Pb, respectively, with54Cr theα-decay of the isotopes259106,260106, and261106 could be observed for the first time. For260106 a spontaneous fission branch of (50 ?20 +30 )% was observed. The isotopes were identified by genetic relationships of α-decay after separation in-flight with the velocity filter SHIP and implantation into a position-sensitive silicon surface-barrier detector. The measured partial fission halflife of the doubly even isotope260106 of (7.2 ?2.7 +4.8 )ms exceeds the predicted values by at least a factor of 40. This result could be explained by the high shell corrections of the ground state mass, derived from the measured α-decay energies. The experimental results show evidence for an island of purely shell stabilized nuclei in the region of deformed isotopes beyond the actinides. 相似文献
228.
A. Bähring E. Meyer I. V. Hertel H. Schmidt 《Zeitschrift für Physik A Hadrons and Nuclei》1985,320(1):141-149
Pronounced polarization effects have been observed in inelastic collisions of laser state-prepared Na*(3p,M L) with Na+ leading to Na*(3d) for the energy rangeE CM=20–45 eV. Using linearly polarized light the dependence of the inelastic process on the alignment of the electronic charge cloud of the Na*(3p) prior to the collision has been measured. In studies with left and right hand circularly polarized light the angular momentum transferred in the collision process has been determined. The results are compared with similar data for the 3p→3s deexitation process studied previously [6]. The density matrix of the Na*(3p) state has been evaluated with respect to the collisional excitation to Na*(3d). Semiclassical calculations based on the coupled channel impact parameter approximation using pseudopotentials [7] and nonadiabatic rotational coupling elements for the Na 2 * system [12] have been performed. The agreement with the experimental results is good, in particular for the higher collision energies. 相似文献
229.
G. Gritzner P. Rechberger Prof. Dr. Viktor Gutmann 《Monatshefte für Chemie / Chemical Monthly》1976,107(3):809-814
The influence of solvents on the redox behaviour of bistriphenylphosphinomercury perchlorate has been investigated by polarographic, voltammetric and potentiometric methods. The electrode process was found to be reversible in acetonitrile, propylene carbonate, N,N-dimethylformamide and dimethyl sulfoxide. An irreversible process was observed in nitromethane employing the dropping mercury electrode as well as in N,N-dimethylthioformamide and N-methyl-2-thiopyrrolidinone employing the rotating platinum electrode. Half wave potentials and diffusion coefficients have been measured. A linear relationship between theE
1/2 and the donor number (DN) of the solvent has been found for the reversible electrode reactions. Ligand replacement occurs in N,N-dimethylthioformamide and N-methyl-2-thiopyrrolidinone.
Mit 1 Abbildung 相似文献
Mit 1 Abbildung 相似文献
230.
Preparation of Ceramic Powders. II. Mg2TiO4, MgTiO3, and MgTi2O5 Formed by Hydrolysis of 2-Ethoxyethylates Solutions of 2-ethoxyethylates of magnesium and titanium in 2-ethoxyethanol submitted to hydrolysis, evaporation and heating of the residue up to 450°C allow to prepare Mg2TiO4, MgTiO3, and MgTi2O5 in an amorphous state with smaller than 1% of volatile components. Highly dispersed powders showing an increased sintering activity are obtained as a result of recrystallization. Mg2TiO4 is formed as inverse spinel phase in a metastable state. 相似文献