The design of heavy load manipulators, robots, vehicles and aeroplanes is based on linear statics. Therefore the information about the type of stress and the stress vector (stress direction and stress factor) is needed. Modern development strategies demand a reduction of material, so a dimensional constraints with security supplement is no longer possible. To fulfil the requirements for sufficient lifetime and safety the online monitoring of stresses during operation is essential. The discovery by Robert Hooke in 1678 concerning the relation between mechanical stress and strain builds the basis for the experimental measurement of stress via strain sensing. Due to the fine characteristics like the high multiplexibility, the high reliability and small failures optical Fiber-Bragg-Grating (FBG) strain sensors have the potential to substitute conventional strain gauges. In this thesis the design and realisation of FBG sensor networks for online-monitoring of dynamic stresses is observed.

Kern dieser Arbeit ist die Untersuchung von drahtlosen Übertragungsverfahren, die mit Hilfe der Hochfrequenztechnik, bzw. oftmals wird der englische Ausdruck Radio Frequenzy (RF) verwendet, eine Kommunikation zwischen einem Sensorsystem mit einer Basisstation aufbauen. So ein Gesamtsystem wird auch als RFIDS-System (Radio Frequency IDentifikation Sensor) bezeichnet. Beim Betrieb werden zuerst die Meßwerte der Sensoren ausgelesen, anschließend findet eine Verarbeitung der Meßergebnisse zu übertragungsfähigen Daten statt und zum Schluß werden die Daten zur Basiseinheit zurückgesendet, wobei in den Daten dann eine Identifikationsnummer des Sensorsystems zur Zuordnung enthalten ist. In der Arbeit wurden mikroelektronische Schaltung zur drahtlosen Signal- und Energieübertragung in Senorsystemen entwickelt. Dabei wurde der Schwerpunkt auf sogenannte passive Systeme gelegt, sie beziehen ihre Energieversorgung aus einer hochfrequenten Trägerschwingung und benötigen keine zusätzliche Energiequelle, wie zum Beispiel eine Batterie. Die Betrachtungen beziehen sowohl die aus der Nachrichtentechnik bekannten Übertragungsverfahren ein, wie auch die Entwicklung von Schaltungen mit äußerst geringem Energieverbrauch. Aus einer Vielzahl von Anwendungsmöglichkeiten wurde ein Bereich herausgesucht, der in der Zukunft eine immer größere Bedeutung erlangen wird, die Medizintechnik. Durch die immer kleiner werdenden Baugrößen sind RFIDS-Systeme zur Implantation beim Menschen oder Tier möglich geworden. Dabei wird zum einen der Ansatz verfolgt einfache Meßsysteme direkt in den Körper zu verlegen, so daß die Infektionsherde wie herausgeführte Zuleitungen entfallen, und zum anderen werden körpereigene Funktionen technisch ersetzt. Dieser Ansatz ist nicht ganz unumstritten und viele Mediziner meinen die Gentechnik sei der bessere Ansatz. Doch erfolgreich arbeitende Implantate, wie das Cochlea-Implantat, zeigen die technischen Möglichkeiten auf. Innerhalb dieser Arbeit werden zwei Anwendungen aus den beiden Bereichen vorgestellt. Neben der unterschiedlichen Funktion der beiden Systeme ist die Datenübertragungsrichtung jeweils eine andere. Bei dem zuerst vorgestellten Retina-Implantat System soll die Netzhaut im Auge stimuliert werden, dazu müssen die Stimulationsdaten down-stream zum Transceiver ins Auge gesendet werden. Das intraokulare Drucksensorsystem soll die Temperatur und den Druck im Auge messen und anschließend die Meßdaten up-stream zur Basiseinheit aus dem Auge heraussenden. Beide Implantate werden passiv betrieben, so daß eine theoretische lebenslange Verweildauer im Körper gewährleistet werden kann. Neben der Energie wird zum Betrieb der digitalen Schaltungselemente auch der Systemtakt mit Hilfe der hochfrequenten Trägerschwingung übertragen und im Implantat extrahiert.

To see this Video, you need the <a href="http://scopes.real.com/real/player/player.html?src=de_cp,rpchoiceintl_de,rpchoiceintl_de_1&lang=de&dc=829828827">RealPlayer 8 Basic-Version</a>. If you are a member of the Gerhard Mercator University of Duisburg, you may use <a href="http://sms-hrz.uni-duisburg.de:8081/install/rp8intra.exe">this version of the Realplayer</a>

Historically, the Gaussian assumption for noise and interferences has dominated signal processing. The justification for this assumption is usually given by the well known central limit theorem which allows an elegant, manageable, and meaningful mathematical description of noise. Nevertheless, some communication scenarios are characterized by impulsive properties on behalf of Gaussian noise, so they are non-Gaussian distributed. Channels which are corrupted with impulsive noise can be found in several domains like for example powerline communications, ethernet traffic, underwater signal processing, or as proven in this project also the multiuser interferences of ultra wideband (UWB) communication systems. After describing and discussing impulsive noise models in detail, a comparison of their distributions has been carried out showing the suitability of the different models for solving selected problems. For example, it is well known that the channel capacity with additive impulsive noise channels is always greater than the one of additive white Gaussian noise (AWGN) channels supposed that the signal to noise ratio (SNR) remains unchanged. In this project the capacity of channels corrupted by impulsive noise has been investigated. An example shows the negative effect of the widely used hard limiter (for impulsive noise clipping) and suggests the use of an alternative one called soft limiter allowing no loss of information. Furthermore, UWB systems have been investigated regarding multiuser interferences. It is proven that the multiuser interferences of impulse radio systems are impulsive. Their probability density function is determined analytically and confirmed by simulation results. Taking this result into account a new receiver structure has been developed allowing the suppression of impulsive noise without use of a limiter. The performance of this receiver is proven by simulation.

This work deals with fiber-optic sensors for measuring pressure und temperature by using the fabry-perot-effect. The realised sensors are made of polymer thin-films with special reflection-coatings. The special kind of sensor takes part in the group of senors in reflection mode transmission mode is possible.

The increasing knowledge about the properties of nanostructured materials is a source of ideas for the improvement of existing and the development of new electronic or opto-electronic devices. One approach is the implementation of nanoparticles as building blocks. Among other synthesis routes, different kinds of gas phase synthesis have been developed which open the possibility to produce nanoparticles with defined properties like chemical composition, crystal structure, shape and size distribution. In order to make use of these properties, the particles have to be transferred from the three dimensional distribution in the gas phase to a two dimensional arrangement on a carrier material, for instance a substrate surface. The first goal of the investiagtion is to describe the microscopic aspects of the deposition process of nanoparticles in the size range between 5 nm and 100 nm at ambient pressure and temperature, under the condition that the particle density (which is the number of particles per unit area)on the substrate surface is below one monolayer. For this purpose, a computer simulation program has been developed, which calculates the particle trajectory that results from the balance of forces on the particle. It takes into account the interaction of incoming individual particles with the substrate surface as well as the interactions with already deposited particles. A parameter study has been carried out in order to point out how the particle arrangement on the substrate depends on the deposition parameters. The results obtained by the computer simulations are compared with experimental results. The parameters varied were the particle diameter, the particle charge, the number of particles per unit area, the substrate properties and the electric field strength. The second goal of the investigation is the structured deposition of nanoparticles from the gas on oxidized silicon substrates by direct deposition from the gas phase of an aerosol. The particles are attracted onto charge patterns created on the plane surface by contact charging. The basic principle of which is that charges cross the interface between an insulator and a metal brought into contact. After the metal is removed, charges retain on the insulator. The charge patterns can either be transferred by a sharp metal tip which is allowed to slide over the substrate surface or by a metal stamp which is pressed on the substrate surface. In the second case even complex structures may be transferred. The resolution of the patterns obtained with these methods is in the order of below 100 nm.

The development of new optoelectronic devices using group-III-nitride-heterostructures requires characterization techniques which give spatially resolved information about the local physical and chemical material properties. The goal of this work was the improvement of analytical STEM-techniques and its application on nano-characterization of III-N-heterostructures. The optimization of electron energy-loss spectroscopy provides a measurement techniques which yields spatially resolved information about bandgap energy and dielectric function on a nanometer scale. A combination of STEM-techniques like EELS, convergent electron diffcration (CBED) and Z-contrast imaging was used to characterize and improve structural properties, interfaces and chemical composition of InGaN-layers. The influence of growth parameters on the enhancement of interface sharpness was demonstrated. Additionally nanoscale fluctuations of the In-content could be proved by Z-contrast imaging and quantified by EELS. It was shown how v-defects in InGaN/GaN-superlattices can be eliminated by modulating the growth temperature during epitaxial growth. The improved EELS-techniques were used for measuring optical properties within III-N-heterostructures. The significance of the results could be demonstrated by a comparison to synchrotron measurements and bandstructure calculations. Due to the high spatial resolution optical properties of local separations and defects could be measured and correlated to chemical and structural properties.

In more recent time electronic, electromechanical, bioelectric and optical technologies, which settle in device products of medical technology, have a crucial portion of medical successes. As extended senses of a physician modern sensors especially in diagnostic systems and also in therapy devices take up a key role. The present study treats the aspects, which are important with the use of sensors in medical applications in the core. In the center of attention are in particular the constructional aspect of the adaptation of medical measuring technique to the employment surrounding field at and in humans. Constructing on fundamental views of the different levels of the sensor adaptation regarding spacial accession, material employment, compatibility of procedures and methods, man-machine-sensor-interaction and law compliance a sensor application typology, which characterizes and differentiates between three main forms of operational areas, forms the structuring framework for an adaptation scheme shown by examples. One concrete problem field each of current own medical technology developments will be motivated regarding its medical topic and typical constructional function conversions and conversion variants will be pointed out and discussed.

This documentation is designed to give the reader insight into the activities of our department. The teaching activities of the department are mainly in the fields of measurement and process technology. In research we are concentrating on the material system aerosol, liquid and / or solid particles suspended in a gas. Of equal interest for us are unwanted aerosols emitted from technical processes and distributed in the atmosphere and wanted product aerosols. The work related to emission and immission of aerosols is mainly concentrating on the implications of the introduction of new EU particulate matter (PMx) Standards. Nanostructured materials and devices can be made using several synthesis technologies. We are concentrating on the synthesis of particles in the gas phase as a very promising route. We develop nanostructured materials with exiting properties, e.g. quantum dots in semiconductors and sensor materials. As the application of aerosols are manifold the research activities of our department have been directed towards various other fields of application. Research priorities at our department are to be found in clean technology, filtration, aerosol measurement technology, physical and chemical characterization of aerosols, synthesis, transport behavior as well as characterization of properties of particles. I would like to acknowledge and convey my gratitude to all those who contributed to the aerosol research work over the last year enabling the successful work of our department.

Im Rahmen dieser Arbeit ist ein neues Meßverfahren zur Online und in-situ-Partikeldetektion auf Oberflächen konzipiert, realisiert und verifiziert worden, das die Detektion der Verunreinigungen durch eine transparente Oberfläche hindurch mit Hilfe der Streulichtmeßtechnik erlaubt. Dieser innovative Schritt erlaubt es, alle Meßsystemkomponenten unterhalb der transparenten Oberfläche anzuordnen. Erstmals wird eine in-situ-Fähigkeit des Meßverfahrens im Gegensatz zu existierenden Oberflächenmeßtechniken erzielt.