Sättigungseigenschaften lokal definierter Formationen

Ohne ZusammenfassungHerrn Professor Dr. W.Gaschütz zum 60. Geburtstag gewidmet     

Efficient methods for the allocation of resources in project networks

Summary The paper surveys available algorithms for resource allocation in project networks that appear computationally efficient. Three cases of resource allocation are considered: time-cost tradeoff, leveling of resources, and constrained resources. Practical analytical methods that guarantee optimal solutions exist only for the time-cost tradeoff problem. Heuristic procedures for problems with constraints on resources do not guarantee but come close to optimal solutions. Relative advantages of heuristic algorithms cannot be assessed in the absence of large scale empirical comparisons.

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Zusammenfassung Die vorliegende Arbeit gibt einen Überblick über Algorithmen für die Verteilung der Ressourcen in Netzwerk-Projekten, die rechnerisch effizient erscheinen. Es werden 3 Fälle der Verteilung von Ressourcen betrachtet: time-cost tradeoff, leveling of resources und constrained resources. Praktische analytische Methoden, die optimale Lösungen garantieren, existieren nur für das time-cost tradeoff Problem. Heuristische Verfahren für Probleme mit Beschränkungen garantieren zwar keine optimalen Lösungen, führen aber eng an sie heran. Die relativen Vorteile, die durch heuristische Programme erzielt werden, können beim Fehlen empirischer Vergleichsmöglichkeiten großen Stils nicht abgeschätzt werden.

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Vorgel. v.:G. Tintner.     

Raman to the limit: tip‐enhanced Raman spectroscopic investigations of a single tobacco mosaic virus

The development of fast identification techniques of viruses is an ongoing important research topic. Conventional virus detection and identification is generally based on various different microbiological methods. However, these techniques are not suitable for the analysis of single virus particles. Therefore, our goal is to establish tip‐enhanced Raman scattering (TERS), providing vibrational spectroscopic information with a spatial resolution less than 50 nm, to characterize single viruses at a molecular level. Here we report, to the best of our knowledge for the first time, about TERS spectra of a tobacco mosaic virus, showing the great capability of this technique. However, the application of the TERS technique for a rapid and direct detection of different species of single viruses is under development, which is useful for a wide range of analytical fields. Copyright © 2008 John Wiley & Sons, Ltd.     

Observation of different azimuthal emission patterns of K+ and of K- mesons in heavy-ion collisions at 1-2 A GeV

Azimuthal distributions of pi+, K+, and K- mesons have been measured in Au+Au reactions at 1.5A GeV and Ni+Ni reactions at 1.93 A GeV. In semicentral collisions at midrapidity, pi+ and K+ mesons are emitted preferentially perpendicular to the reaction plane in both collision systems. In contrast for K- mesons in Ni+Ni reactions, an in-plane elliptic flow was observed for the first time at these incident energies.     

Emission pattern of high-energy pions: A new probe for the early phase of heavy-Ion collisions

Recent results from CLEO on B-->Kpi indicate that the phase gamma may be substantially different from that obtained from other fit to the KM matrix elements in the standard model. We show that gamma extracted using B-->Kpi,pipi is sensitive to new physics occurring at loop level. It provides a powerful method to probe new physics in electroweak penguin interactions. Using effects due to anomalous gauge couplings as an example, we show that within the allowed ranges for these couplings information about gamma obtained from B-->Kpi,pipi can be very different from the standard model prediction.     

Eine Kennzeichnung der geraden Bewegungs-Gruppen endlicher euklidischer Ebenen

Ohne Zusammenfassung     

First evidence for different freeze-out conditions for kaons and antikaons observed in heavy-ion collisions

Differential production cross sections of K- and K+ mesons have been measured in Ni+Ni and Au+Au collisions at a beam energy of 1.5 A GeV. The K(-)/K(+) ratio is found to be nearly constant as a function of the collision centrality and system size. The spectral slopes and the polar emission pattern differ for K- and K+ mesons. These observations indicate that K+ mesons decouple earlier from the fireball than K- mesons.     

Neutron production in extended Cu-target irradiated with relativistic C-ions at Dubna, as studied with SSNTD and nuclear chemistry

An extended Cu-target was irradiated with 22 and 44 GeV carbon ions. The target was in contact with a (CH₂)_n-block for the moderation of secondary neutrons. Small holes in the moderator were filled with either lanthanium salts or uranium oxide. The reaction ¹³⁹La (n,γ) ¹⁴⁰La was studied via the decay of ¹⁴⁰La (40 h), and the reaction ²³⁸U (n, γ) ²³⁹U ²³⁹Np was studied via the decay of ²³⁹Np (2.3 d). In addition, a variety of solid state nuclear track detectors (SSNTD) were used. Results will be presented. The yields for the formation of (n, γ) products agree essentially with other experiments on extended targets carried out at the Synchrophasotron LHE, JINR (Dubna). To a first approximation, the breeding rate of (n, γ) products, as well as the specific track density, seen with several SSNTDs, doubles when the carbon energy is increased from 22 to 44 GeV. If, however, results at 44 GeV are compared in detail to those at 22 GeV, we observe an excess of (37 ± 9) % in the experimentally observed ²³⁹Np-breeding rate over theoretical estimations. Experiments using solid state nuclear track detectors are giving similar results. We also observed in the past such excess in the yield of other secondary particles in relativistic heavy ion interactions above a total energy of approximately 35–40 GeV.