On the efficient implementation of conditional critical regions and the construction of monitors

Summary A method is presented that allows the efficient implementation of conditional critical regions combined with scheduling of the waiting processes. It is based on the knowledge of static and invariant relations that exist among the conditional critical regions of a process system. Mathematical methods are applied in order to show the nature of these relations, and to determine them for practical applications.By collecting the conditional critical regions in a program module, a monitor is obtained. Its rather abstract user level allows clear and well structured programming style. It also shows some advantages in comparison to other monitor proposals on the implementation level.Work done mainly at the Fakultät für Informatik, Universität Karlsruhe, Karlsruhe, and also at the Department of Computer Science, University of Toronto, Toronto.     

Flip the tip: an automated,high quality,cost-effective patch clamp screen

The race for creating an automated patch clamp has begun. Here, we present a novel technology to produce true gigaseals and whole cell preparations at a high rate. Suspended cells are flushed toward the tip of glass micropipettes. Seal, whole-cell break-in, and pipette/liquid handling are fully automated. Extremely stable seals and access resistance guarantee high recording quality. Data obtained from different cell types sealed inside pipettes show long-term stability, voltage clamp and seal quality, as well as block by compounds in the pM range. A flexible array of independent electrode positions minimizes consumables consumption at maximal throughput. Pulled micropipettes guarantee a proven gigaseal substrate with ultra clean and smooth surface at low cost.     

Electrical, optical and morphological properties of nanoparticle indium-tin-oxide layers

Porous layers were prepared from DEGUSSA's ITO (In₂O₃:Sn) nanoparticle dispersion by doctor blading followed by annealing in air. We investigated the influence of various annealing parameters on electrical, optical and morphological thin film properties.Conductance rises with increasing annealing temperature and time by more than three orders of magnitude up to 44 Ω^− 1cm^− 1. Besides this we found an abrupt decrease in free charge carrier concentration above a critical annealing temperature of 250 °C, which leads to a step in conductance curve. In spite of particle growing during annealing no decrease in porosity was observed and in opposite to compact material, nanoparticle layers do not exhibit an appreciable shrinkage below recrystallisation temperature. These both indicate a densification hindering particle pinning effect, which is believed to be currently the main obstruction to achieve higher electrical conductivities.     

Extensible Prototyping for pragmatic engineering of knowledge-based systems

Knowledge-based systems (KBSs) have been built and practically applied in various contexts for decades. Yet, they still challenge developers by their complexity: Apart from a sound knowledge base they likewise require comprehensive user interface (UI) and interaction design for supporting the task at hand optimally. However, current KBS-Engineering methodologies still mostly focus on knowledge base development, regarding UI/interaction design a more incidental, low priority task. Thus, the UI often is developed in a rather ad hoc manner, thereby neglecting the potential of experimental design and creating reusable solutions. The integration of (rapid) evolutionary prototyping activities with KBS Engineering offers the chance for incorporating UI/interaction design more prominently into the process while at the same time leveraging the overall development task; specifically, we propose Extensible Prototyping as a tailored prototyping approach and we suggest its integration with the Agile Process Model for knowledge-based systems in this paper. For practical support, we further introduce the customized prototyping and knowledge systems engineering tool ProKEt, and we report on practical experiences with applying both the approach and the tool.     

Integrated-optic polarisation convertor on (001)-InP substrate

A novel TE/TM convertor is proposed and demonstrated which is fabricated on (001)-InP substrate and can be integrated with TE-TM phase shifters to provide a general polarisation transformation. Some aspects of the technological realisation and first results are given; in a first attempt, a polarisation rotation of about 20 deg by 20 V could be demonstrated.     

A high average power dual slab Nd:glass zigzag laser system

A dual slab Nd:LHG5 glass zigzag optical path laser was constructed with single-sided pumping and tested. A single slab (0.63 times 5.6 times 35cm) produced 80 W in an oscillator with an accompanying distortion of only 3 fringes (632.8 nm) as measured by a single-pass interferogram through the slab. Performance was achieved by producing uniform pumping and cooling of the slabs, and by controlling the distortion at the slab ends with pump shields.     

Study of individual grown-in and indentation-induced dislocations in GaN by defect-selective etching and transmission electron microscopy

Vickers diamond indentation at 370°C has been employed to introduce dislocations into the plate-like (000-1) N-polar GaN single crystals. It has been established that using standard Vickers diamond indenter, well-defined ‘rosettes’ of defects are formed under 1.5–2 N load applied for 10 min. The resolved patterns of dislocation-related etch pits are formed using molten KOH–NaOH eutectic (E) at 200°C for 1.5–2 min. Individual grown-in dislocations are revealed by this E etch in the GaN matrix. Transmission Electron Microscopy confirmed the correlation of etch pits to individual dislocations emerging at the surface. Nano-crystalline material was found in the highly deformed central region of the indentation rosette. The structure of these nano-crystals was analyzed using electron diffraction. Speculative explanation on a phase transition induced by high local pressure is briefly discussed.