Structural and compositional analysis of (InGa) (AsSb)/GaAs/GaP Stranski–Krastanov quantum dots

We investigated metal-organic vapor phase epitaxy grown (InGa)(AsSb)/GaAs/GaP Stranski–Krastanov quantum dots (QDs) with potential applications in QD-Flash memo...     

Toward methods for supporting the anticipation-feedback loop in user interface design

Recent research has compared different usability evaluation methods with respect to their effectiveness and efficiency. The paper analyses the impact of different usability evaluation methods on design problem-solving processes of individual designers and evaluators. It is proposed that usability evaluation methods have to be divided into two categories according to their fundamentally different way of supporting the design for usability: (1) guideline-based methods and (2) methods based on the mental generation of scenarios and anticipation of user goals. We present data from an experimental study that shows that these two types of methods entail differences in the perspective-taking processes. Furthermore, the results indicate that the methods have a differential impact on the general problem-solving strategy, i.e. whether to use a top-down, breadth-first or a depth-first approach. Possible implications for the development of techniques that support the design of usable systems are discussed.     

BASF NanoSelect? Technology: Innovative Supported Pd- and Pt-based Catalysts for Selective Hydrogenation Reactions

An innovative BASF catalyst manufacturing technology (NanoSelect?) is introduced which allows production of heterogeneous catalysts with excellent control over metal crystallite sizes. NanoSelect? technology enabled the development of Pd catalysts which are lead-free Lindlar catalyst replacements in alkyne-to-cis-alkene hydrogenations. NanoSelect? Pt catalysts showed excellent chemoselectivity in substituted nitro-arene hydrogenation reactions without build-up of hydroxylamine intermediates. All NanoSelect? produced catalysts show markedly higher activity per gram of metal leading to ten-fold less use of precious metal.     

Shift Register Graphs and Permutation/Reset Automata

Abstract

This note completes the author's study of embedding of cascade products of permutation or reset automata in so-called shift register graphs.     

Contribution of Solutes to Density Stratification in a Meromictic Lake (Waldsee/Germany)

Density differences are the key parameter for stratification stability. We used data from the iron-meromictic Waldsee, Germany, a lignite mine pit lake, to quantify the contribution of single solutes to water density and analyzed the density gradient. Iron meromictic lakes maintain their density gradient through chemical reactions. Hence, quantifying the contributions of separate solutes is essential for understanding the entire process. Based on solute concentrations and literature values of partial molal volumes, substance specific density contributions were quantitatively evaluated. Then, by direct measurements of the density of IHSS Waskish peat fulvic acid, we quantified the density contribution of dissolved organic carbon (DOC). While several solutes contributed to the density throughout the water column, only those substances that occurred at higher concentrations in the anoxic monimolimnion than in the oxic mixolimnion were crucial to sustaining the density difference between the two layers. In Waldsee, the density difference between monimolimnion and mixolimnion was attributed to dissolved Fe²⁺ (0.23?g/L, resulting in a 45?% of the density difference due to solutes) and to the carbonate system (HCO₃ ^?, about 0.16?g/L and CO₂, 0.03?g/L) while Ca²⁺ and DOC delivered only a small contribution. In summer, total density differences were dominated by temperature differences; during winter, solutes sustained meromixis. Finally, we present a complete list of specific density fractions for basically all of the density-relevant substances in fresh waters.