Bøger udgivet af Sudwestdeutscher Verlag Fur Hochschulschriften AG

The medicine technology for monitoring the depth of anesthesia currently in use bases on monitoring phenomenological health parameters such as heart frequency, frequency of breathing or blood pressure. However, these parameters are rather unreliable because they are greatly influenced by other medication typically given during anesthesia. As a result, roughly 0.3% of all patients become aware during surgery. The sensor concept treated in this work deals with the core of this problem. In principle it enables the depth of anesthesia to be precisely controlled. The topic of this work is to prove the concepts and ideas behind the patent DE10 2004 037 519 B4 corresponding to the sensor principle valid by showing the reaction of a two-mode laser system to solutions of the anesthetic drug Propofol in liquid phase. The result convinces by its simplicity and clarity; the reaction of the laser to Propofol is not only linear, but also independent of the solvent used. Furthermore, it bases on the effect of mode competition, which is postulated in the patent.

This work presents experimental results on intersubband transitions in p-type SiGe heterostructures, where time-resolved photocurrent studies allow the determination of intersubband relaxation times of relevance for the development of a silicon-based quantum cascade laser. Inter-valence band relaxation by the emission of LO phonons leads to ultra-short lifetimes of the excited hole state around 500 fs for transition energies above the LO phonon energy, as determined in the course of this work by photocurrent pump-pump experiments employing a free-electron-laser. In contrast, for transition energies below the LO phonon energy, intersubband relaxation times are in the range of ten picoseconds. The concept of diagonal transitions poses a means of increasing these relaxation times. This work demonstrates a voltage-induced change between a spatially direct and a diagonal intersubband transition and a consequential bias tuning of the associated decay times by a factor of two. In addition, this thesis covers novel SiGe quantum well infrared photodetector concepts as well as an innovative approach for the fabrication of blocked-impurity band detectors operating in the terahertz regime.

The present work treats several asymptotic properties of stochastic flows in Euclidean space, whose distributions are frequently assumed to be invariant under rotations of the state space. Despite the fact that the study of some of these flows goes back to the 1950's new models are introduced. The first main chapter treats the asymptotic behavior of the shape of the set of points in the plane that has been visited up to some time by a stochastic flow. It is shown in the case of a planar isotropic Brownian flow that this shape is deterministic in probability. The second main result is the extension of the so-called Margulis-Ruelle Inequality to the case of an isotropic Ornstein-Uhlenbeck flow, which is a start to make Pesin theory suitable for the case of a non-compact state space. The last two main chapters are devoted to the asymptotic expansion of the spatial derivative of a stochastic flow taking the supremum over a compact set of initial points in space. It is shown that this expansion is at most exponentially fast in time and a deterministic bound on the expansion speed is obtained.

The issue whether to pioneer or to follow is as old as strategic management itself. Put shortly, there are two opposite perspectives. Conventional literature on management claims that it pays to be first in a new market. However, this perspective was challenged during the last decade. The latter perspective argues that it is more wise to let others develop the market first and enter it when it turns out to be attractive. Evidence from practice derives exclusively from developed and mature markets such as the US or EU. Yet, in the context of EM there virtually exists no research on this issue. Therefore, this study aims to shed light on the above debate by investigating the automotive industry in two of the most important EM - China and Brazil. The research reveals how order-of-entry advantages develop and what factors enhance or mitigate them in a highly protected market context. Strategic implications are drawn for each group of entrants. As a firm is more often a follower than a pioneer, this study focuses on how followers should enter into EM and what kind of resources they need to establish successfully at the new terrain.