Science and technology in the region: The output of regional science and technology, its strengths and its leading institutions

Summary We operationalize scientific output in a region by means of the number of articles (as in the SciSearch database) per year and technology output by means of the number of patent applications (as in the database of the European Patent Office) per priority year. All informetric analyses were done using the DIALOG online-system. The main research questions are the following: Which scientific and technological fields or topics are most influent within a region and which institutions or companies are mainly publishing articles or holding patents? Do the distributions of regional science and technology fields and of publishing institutions follow the well-known informetric function? Are there - as it is expected - only few fields and few institutions which dominate the region? Is there a connection between the economic power of a region and the regional publication and patent output? Examples studied in detail are seven German regions: Aachen, Düsseldorf, Hamburg, Köln (Cologne), Leipzig - Halle - Dessau, München (Munich), and Stuttgart. Three different indicators were used, science and technology attraction of a region (number of scientific articles and patents), science and technology intensity (articles and patents per 1,000 inhabitants), and science and technology density (articles and patents per 1 billion EURO gross value added). Top region concerning both attraction and intensity is Munich, concerning density it is Aachen.     

Controlling a Semiconductor Optical Amplifier Using a State-Space Model

We derive nonlinear and linear state-space control models for a multichannel semiconductor optical amplifier. Verified against the governing partial differential equations through simulation, the linear model tracks modulations up to 20% qualitatively well. Linear feedback control is then employed to design two interchannel crosstalk suppressing systems, one using state feedback into the electronic drive current and the other using optical output feedback into an optical control channel; the controller designed with the linear model is seen to work well even with 100% modulations of the nonlinear system. This linear state-space model opens the way for further robust analysis, design and control of integrated active photonic circuits     

Fast frequency-step-tunable high-power gyrotron withhybrid-magnet-system

The TE_22,6 1 MW gyrotron operated at Forschungszentrum Karlsruhe (FZK) at frequencies between 114 and 166 GHz has been investigated with respect to the fast-frequency tunability in the frequency range from 132 to 147 GHz. For that purpose, the gyrotron has been equipped with a special hybrid-magnet system consisting of superconducting (sc) magnets in the cryostat and additional normal conducting (nc) copper magnets with a fast time constant. Some special problems due to the magnetic coupling between the different magnets were investigated by calculation and experiment. Making use of these investigations some different current regulation systems for the nc magnets were implemented and tested experimentally. Finally a step-tuning operation between the modes from TE_20,6 to TE_24,6 in time steps of 1 s has been achieved     

Stresses and strains in the steel containment resulting from transient pressure and temperature loading during loss-of-coolant accident

Posttest calculations of stresses and strains in the steel containment of the German research reactor HDR were performed for a simulated LOCA. The results of the theoretical investigations will be presented and compared to experimental findings. The pressure and temperature loading of the shell was determined with the thermodynamic code COFLOW on the basis of a multi-compartment model. Using a three-dimensional finite element model the temporal behaviour of the containment was calculated employing the structural mechanics code ASKA. Global bending deformations and local negative straining of the steel shell is discussed. Theoretical and experimental results agree in most cases rather well. Reasons for deviations will be discussed. The specific behaviour of strains found in the vicinity of locally heated areas will be explained by means of analytical considerations.     

Bücher

Ohne Zusammenfassung VDI     

A neuro-fuzzy supervisory control system for industrial batchprocesses

The automation of complex industrial batch processes is a difficult problem due to the extremely nonlinear and variable system behavior or the conflicting goals within the different process phases. The introduction of a single multiple-input multiple-output controller is not useful because of the rather high design effort and the low transparency of its complex structure. A more suitable hierarchical fuzzy-logic (FL) based supervisory control concept is proposed. It permits the decomposition of the complex control problem into a series of smaller and simpler ones. In the upper level of the hierarchy the FL-based supervisory controller classifies the actual process phase in terms of the available process sensor signals and activates dynamically the appropriate situation specific low-level controllers. The paper presents the generic concept of the FL supervisory controller that comprises both a FL process diagnosis and a control mode selection as well as experiences with the industrial application     

Progress Report on Superconducting Proton Linacs

The work on superconducting proton and heavy ion accelerators will be reviewed. The helix seems to be an adequate structure for low velocity particles. For energies above 15 MeV/N other types of accelerating structures may be used. Superconducting Nb helices were developed at several places. A maximum gradient of 2.8 MV/m witha Q of 2.109 has been obtained recently in Karlsruhe with a ?/2 Nb helix at 90 MHz. First proton acceleration in superconducting helical structures indicates the status of the new technology.     

Phased-array wavelength demultiplexer with flattened wavelengthresponse

A four-channel phased-array wavelength demultiplexer with a flattened wavelength response has been realised for the first time in InP/InGaAsP at 1.54 μm by employing multimode output waveguides. The device has 2 nm channel spacing and a flat response (within 1 dB) of 17 nm