Light propagation and fluorescence quantum yields in liquid scintillators

For the simulation of the scintillation and Cherenkov light propagation in large liquid scintillator detectors a detailed knowledge about the absorption and emission spectra of the scintillator molecules is mandatory. Furthermore reemission probabilities and quantum yields of the scintillator components influence the light propagation inside the liquid. Absorption and emission properties are presented for liquid scintillators using 2,5-Diphenyloxazole (PPO) and 4-bis-(2-Methylstyryl)benzene (bis-MSB) as primary and secondary wavelength shifter. New measurements of the quantum yields for various aromatic molecules are shown.Comment: 11 pages, 3 figures, 1 tabl

Taxes, Keiretsu Affiliation, and Income Shifting

This paper provides evidence that keiretsu group member firms are subject to lowereffective tax rates than independent firms in Japan. As one explanation for this phenomenon, wedevelop a hypothesis that keiretsu firms strategically shift financially reported income amongaffiliates in order to reduce overall effective tax rates. Empirical evidence supports this income-shifting hypothesis since the positive relationship between pretax return m firm value and marginaltax rate status is significantly mitigated by keiretsu membership. Further, it appears that keiretsuincome shifting activities intensify when Japanese firms face economic recession, contrastingconjecture of weakening strength of keiretsu affiliation during this period. We also find evidencesupporting the view that benefactors of shifted income are compensated via increased dividends

Plasmanitrierung eines lufthärtenden Schmiedestahls mit mittlerem Mangangehalt

The impact of plasma nitriding on the microstructure and the hardness of a recently developed 4 wt.-% medium manganese steel are presented. In contrast to standard quench and tempering steels, the investigated material achieves its martensitic microstructure by air-cooling from the forging heat, which enables the reduction of the carbon footprint of the forged components. The influence of nitriding on this grade of steel has not been investigated so far, but fundamental differences in comparison to standard nitriding steels are expected due to the increased manganese concentration. To address this issue, nitriding treatments with different temperatures (350 °C, 580 °C and 650 °C) have been performed, followed by examinations of the microstructure, the phase composition, the obtained hardness profiles and the tensile properties of the bulk material after nitriding, accompanied by thermodynamic equilibrium calculations. It is demonstrated that after nitriding at 580 °C similar hardness profiles like standard nitriding steels are achieved, with a shorter process as austenitization and hardening were omitted, reaching a hardness of approximately 950 HV0.1. Furthermore, it was demonstrated that austenite can be stabilized by manganese and nitrogen partitioning to room temperature during nitriding in the intercritical phase region.Es wird der Einfluss des Plasmanitrierens auf das Gefüge und die Härte eines kürzlich entwickelten 4-Gew.-%-Mittelmanganstahls vorgestellt. Im Gegensatz zu Standard-Vergütungsstählen erreicht der untersuchte Werkstoff sein martensitisches Gefüge durch Luftabkühlung aus der Schmiedewärme, was die Reduzierung des Kohlenstoff-Fußabdrucks der Schmiedeteile ermöglicht. Der Einfluss des Nitrierens auf diese Stahlsorte wurde bisher noch nicht untersucht, doch werden aufgrund der erhöhten Mangankonzentration grundlegende Unterschiede im Vergleich zu Standard-Nitrierstählen erwartet. Um diese Frage zu klären, wurden Nitrierbehandlungen bei verschiedenen Temperaturen (350 °C, 580 °C und 650 °C) durchgeführt und anschließend die Mikrostruktur, die Phasenanteile, die erreichten Härteprofile und die Zugeigenschaften der Matrix nach dem Nitrieren untersucht, begleitet von thermodynamischen Gleichgewichtsberechnungen. Es wird gezeigt, dass nach dem Nitrieren bei 580 °C vergleichbare Härteprofile wie bei Standard-Nitrierstählen erzielt werden, wobei der Prozess deutlich verkürzt ist, da Austenitisierung und Härtung entfallen und eine Härte von etwa 950 HV0,1 erreicht wird. Darüber hinaus wurde gezeigt, dass Austenit durch Mangan- und Stickstoffpartitionierung bei Raumtemperatur während des Nitrierens im interkritischen Phasenbereich stabilisiert werden kann

Lazy AC-Pattern Matching for Rewriting

We define a lazy pattern-matching mechanism modulo associativity and commutativity. The solutions of a pattern-matching problem are stored in a lazy list composed of a first substitution at the head and a non-evaluated object that encodes the remaining computations. We integrate the lazy AC-matching in a strategy language: rewriting rule and strategy application produce a lazy list of terms.Comment: In Proceedings WRS 2011, arXiv:1204.531

Confluent Orthogonal Drawings of Syntax Diagrams

We provide a pipeline for generating syntax diagrams (also called railroad diagrams) from context free grammars. Syntax diagrams are a graphical representation of a context free language, which we formalize abstractly as a set of mutually recursive nondeterministic finite automata and draw by combining elements from the confluent drawing, layered drawing, and smooth orthogonal drawing styles. Within our pipeline we introduce several heuristics that modify the grammar but preserve the language, improving the aesthetics of the final drawing.Comment: GD 201

Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection

Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.Comment: 16 pages, 4 figures, 5 table

Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection

Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.Comment: 16 pages, 4 figures, 5 table

Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection

Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.Comment: 16 pages, 4 figures, 5 table

Loops under Strategies ... Continued

While there are many approaches for automatically proving termination of term rewrite systems, up to now there exist only few techniques to disprove their termination automatically. Almost all of these techniques try to find loops, where the existence of a loop implies non-termination of the rewrite system. However, most programming languages use specific evaluation strategies, whereas loop detection techniques usually do not take strategies into account. So even if a rewrite system has a loop, it may still be terminating under certain strategies. Therefore, our goal is to develop decision procedures which can determine whether a given loop is also a loop under the respective evaluation strategy. In earlier work, such procedures were presented for the strategies of innermost, outermost, and context-sensitive evaluation. In the current paper, we build upon this work and develop such decision procedures for important strategies like leftmost-innermost, leftmost-outermost, (max-)parallel-innermost, (max-)parallel-outermost, and forbidden patterns (which generalize innermost, outermost, and context-sensitive strategies). In this way, we obtain the first approach to disprove termination under these strategies automatically.Comment: In Proceedings IWS 2010, arXiv:1012.533

Doubly stabilized perovskite nanocrystal luminescence downconverters

Halide perovskite nanocrystals (NCs) have emerged as a promising material for applications ranging from light-emitting diodes (LEDs) to solar cells and photodetectors. Still, several issues impede the realization of the nanocrystals' full potential, most notably their susceptibility to degradation from environmental stress. This work demonstrates highly stable perovskite nanocrystals (NCs) with quantum yields as high as 95 % by exploiting a ligand-assisted copolymer nanoreactor-based synthesis. The organic ligands thereby serve a dual function by enhancing the uptake of precursors and passivating the NCs. The polymer micelles and ligands thus form a double protection system, shielding the encapsulated NCs from water-, heat- and UV-light-induced degradation. We demonstrate the optoelectronic integrability by incorporating the perovskite NCs as spectrally pure downconverters on top of a deep-blue-emitting organic LED. These results establish a way of stabilizing perovskite NCs for optoelectronics while retaining their excellent optical properties