Extensible Software Systems in Oberon

Abstract

Extensible software systems play an important role in prototyping environments where a fast compile-and-test turnaround is required. Typically, extensible software systems combine ways to reuse code, an approach to object-oriented programming, and ways to preserve state from one session to another. In this article we introduce the Oberon system from the perspective of an extensible system. In Oberon, the stated requirements manifest themselves as separate hierarchies related to modularity, the type system, runtime system organization, and persistency. We discuss issues related to these hierarchies and the approaches selected in Oberon for their implementation. The article is mainly a short introduction to Oberon and a summary of what has been accomplished with this system.     

The formation of percolative composites with a high dielectric constant and high conductivity

The dielectric constant and electrical conductivity of a composite of two insulators, poly(1,1-difluoroethylene) (yellow) and K(2) CO(3) (white), increased dramatically near the percolation threshold?f(c) (f=concentration of K(2) CO(3) ). This intriguing phenomenon can be interpreted in terms of interface percolation caused by the formation of chemically activated interfaces.     

Surface wetting in liquid-liquid-solid triphase systems: solid-phase-independent transition at the liquid-liquid interface by lewis Acid-base interactions

Interfacial phenomena: A solid-phase-independent strategy for tuning the surface wettability is presented. Lewis acid-base interactions at the oil-water interface can greatly decrease the liquid-liquid interfacial tension and induce oleophilic to superoleophobic wetting transition on a nonresponsive microstructured surface.     

Chemical etching of zinc oxide for thin-film silicon solar cells

Chemical etching is widely applied to texture the surface of sputter-deposited zinc oxide for light scattering in thin-film silicon solar cells. Based on experimental findings from the literature and our own results we propose a model that explains the etching behavior of ZnO depending on the structural material properties and etching agent. All grain boundaries are prone to be etched to a certain threshold, that is defined by the deposition conditions and etching solution. Additionally, several approaches to modify the etching behavior through special preparation and etching steps are provided.     

Reactions in droplets in microfluidic channels

Fundamental and applied research in chemistry and biology benefits from opportunities provided by droplet-based microfluidic systems. These systems enable the miniaturization of reactions by compartmentalizing reactions in droplets of femoliter to microliter volumes. Compartmentalization in droplets provides rapid mixing of reagents, control of the timing of reactions on timescales from milliseconds to months, control of interfacial properties, and the ability to synthesize and transport solid reagents and products. Droplet-based microfluidics can help to enhance and accelerate chemical and biochemical screening, protein crystallization, enzymatic kinetics, and assays. Moreover, the control provided by droplets in microfluidic devices can lead to new scientific methods and insights.