The thesis describes the investigation of high-resolution MQ MAS NMR in rigid spin-1/2 systems. Formerly, MQC techniques were mainly applied to systems of small molecules, the newly developed MQC technique in this thesis, the 1H-MQC-filtered-MAS-NMR method, can be well applied to study the heterogeneity of inorganic and organic materials, such as silica gel, homopolymers, copolymers and their blends. In this thesis two multiple-pulse sequences were adopted: the three-pulse and the time-reversible eight-pulse sequence. The former has the advantage that the cycle time, i.e. the excitation time can be adjusted to arbitrary values, therefore it can be used to generate 1H MQC in coupled spin-1/2 systems for a wide range of dipolar interactions, especially to pump 1H MQC from a rigid system, such as the crystalline phase of polymers. But it has disadvantages: it is sensitive to chemical shifts and resonance offsets, and has low efficiency in exciting higher order coherences. The latter has higher efficiency in exciing higher order coherences and is not sensitive to chemical shifts and resonance offsets, but it has a long cycle time, so it is only effective when the dipolar interactions are not strong such as in the amorphous phase of polymers

Molekularstrahlepitaxie, Technologie und Modellierung von InP-basierenden Heterostrukturfeldeffekttransistoren mit reduzierten Stoßionisationsraten und additiven Löcher- und Elektronenbarrieren zur Erzielung kleinster Leckströme und grössten Durchbruchsspannungen bei höchsten Schaltgeschwindigkeiten

Im Rahmen dieser Arbeit wurden die Metallzentren der Cytochrom-c-Oxidasen (CCO) aus Thermus thermophilus (T.t.), aus Paracoccus denitrificans (P.d.) und dreier mit gentechnischen Methoden erzeugten Proteine (M227I, C216S, SU II) mit Hilfe der EXAFS-Spektroskopie untersucht. Die EXAFS-Messungen an der löslichen Domäne der Untereinheit II der CCO aus P.d. exprimiert in E. coli (SU II) ermöglichten erstmals die Untersuchung eines CuA-Zentrums mit EXAFS ohne die Überlagerung durch Signale von CuB. Das CuA-Zentrum ist ein zweikerniges Zentrum mit sehr kurzem Cu-Cu-Abstand dessen Kupfer-Atome von zwei (mü)2-Schwefel-Liganden verbrückt werden. Terminal an die beiden Cu-Atome koordiniert jeweils ein Histidin. Es kann nicht ausgeschlossen werden, daß die in verschiedenen Arbeiten als schwach koordinierend diskutierten Methionin- und Glutamat-Backbone-Liganden maskiert und damit nicht zu detektieren sind. Somit ist eine CuA-Zentrum. Am CuB koordinieren drei Histidinliganden. Der mittlere Fe-Cu-Abstand im Fea3/CuB-Zentrum beträgt 3,99 Å. Die beiden Eisenatome des Enzyms sind durch je einen Porphyrin-Ring koordiniert. Das Feb-Zentrum vervollständigt seine Koordination durch zwei axial zum Ring gebundene Histidin-Reste, das Fea3 durch einen axial gebundenen Histidin-Rest. Der Vergleich der EXAFS-Messungen an der CCO aus P.d. mit denen für die CCO aus T.t. zeigt, daß die Metallzentren der beiden Enzyme bis auf Details identisch sind. Das Kupfer-EXAFS der Mutante M227I der CCO aus P.d. zeigt eine Erhöhung der mittleren Koordinationszahl der Kupfer-Atome im mutierten CuA-Zentrum auf vier. Die daraus resultierende strukturelle Änderung bedingt eine Spin-Lokalisation im nativ Spin-delokalisierten Zentrum. Offensichtlich ist das in CCO hochkonservierte Methionin 227 erforderlich, um die einzigartige geometrische und elektronische Struktur des CuA-Zentrums zu stabilisieren. Die spektroskopischen Untersuchungen an der Mutante C216S der CCO aus P.d. zeigen statt des CuA-Zentrums ein einkerniges Kupfer-Zentrum an der Bindungsstelle des dem konservierten Methionin 227 zugewandten Kupferatoms des CuA-Zentrums. Das Zentrum wird durch ein Histidin, ein Cystein, ein Methionin und einen weiteren Liganden (S/Cl) tetraedrisch koordiniert. Es wird deutlich, daß das im CuA verbrückend koordinierende Cystein 216 essentiell zur Bildung eines homodinuklearen Zentrums ist. Ausserdem wurde eine optimierte Meßstrategie entworfen, mit der die zur Verfügung stehende Meßzeit zugunsten der kritischen Bereiche des Spektrums teilweise umverteilt wird. Es wurde eine neuartige Methode zur quantitativen Bestimmung der statistischen Qualität von EXAFS-Spektren entwickelt. Mit Hilfe dieser Methode konnte ein neuartiges dynamisch-adaptives Verfahren zur Glättung von Spektren entwickelt und programmiert werden. Es wurden zusätzlich Erweiterungen zur Standardsoftware Cerius2 entwickelt. Die Erweiterungen ergänzen die Funktion und die Oberfläche des Programms.

In this work optical measurement techniques are developed and performed for the on-wafer and in-circuit characterisation of coplanar HF devices and circuits. Electro-optic sampling methods have been used most commonly deploying the Pockels-effect. It can shown, that also electroabsorptive mechanisms can be used for the measurement of HF signals. In addition, optical heterodyning is applied to transfer the microwave signal that is to detect to lower frequency ranges. - Gegenstand der vorliegenden Dissertation ist die Entwicklung einer optischen Messtechnik, die zur Untersuchung und Charakterisierung von koplanaren Hochfrequenz-Bauelementen und -Schaltungen eingesetzt werden kann. Hervorragende Ergebnisse konnten bislang mit der elektrooptischen Messtechnik erzielt werden, welche den Pockels-Effekt zwischen einem durch das Bauelement propagierenden Mikrowellensignal und einem optischen Abtaststrahl ausnutzt. Die vorliegende Arbeit zeigt, dass auch elektroabsorptive Effekte für optische Messverfahren eingesetzt werden können. Sie präsentiert zudem die Möglichkeit, durch die Heterodyn-Technik, also das geeignete Mischen zweier wellenlängenverstimmter cw-Laser, das Mikrowellensignal in niedrigere und damit einfacher zu messende Frequenzbereiche herunterzutransferieren.

This thesis describes the measurement of xenon diffusion coefficients in porous media via Pulsed Field Gradient (PFG) NMR spectroscopy. The thesis includes the characterization of a phase seperated polymer blend (PP/EPDM) in comparison to the pure components, the characterization of a number of commercially available semi-crystalline polymers and the characterization of a new microporous solid catalyst (silconimidonitride) with three different pore sizes by the diffusional behaviour of xenon in these materials. In addition to that a new theory is described which correlates the chemical shift of 129Xe NMR adsorption resonances with the corresponding xenon diffusion coefficients.

Reactions of photoexcited coumarins and their thia analogues with captodative alkenes have been investigated, with special emphasis on the nature of the excited states and the specific influence of the substrates on regio- and stereoselectivity of the observed [2+2]-photocycloadditions. Aside of two coumarin thiones all coumarins investigated regioselectively add captodative alkenes at the pyranone moeity giving rise to head-to-tail [2+2]-photocycloadducts with donor-endo adducts as prevailing isomers. The observed regio- and stereoselectivities can be best explained if a 1,4-biradical is assumed as intermediate in the photocycloaddition.

This thesis describes the optimization and characterisation of an integrated fluxgate sensor. It is fabricated with a CMOS-compatible technology for planar coils with ferromagnetic cores. Limitations of sensor measurement range and linearity are analyzed by analytical and numerical calculations of stray fields and demagnetizing effects in the cores coupled with signal analysis of the calculated coil output voltage. The sensor resultion is limited by magnetic domain effects. Based on these results the sensor layout is optimized for the compass application. Electrical and magneto-optical methods for on wafer characterisation of the ferromagnetic layer, the electrical and magnetical coil parameters and the sensor itself are developed and meet production requirements.

A procedure for yield prediction and reliability estimation for microlectronic circuit manufacturing was developed in this thesis. Therefore the interaction between defects distributed randomly and chip layout structures was investigated mainly. At first a new method for the optical defect measurement has been introduced considering the real defect outline which is unavoidable to extract the correct defect size distribution. The simulation tool CALYPSO was created to detect the sensitivity of the layout on defects of various types and sizes. The code benefits from a novel combination of well known simulation principles to reach a very high speed of the numerical runs. Not only yield relevant defects can be considered but latent and build-in reliability defects leading to lifetime shortening too. For this two additional special modules have been implemented. So CALYPSO can not only predict the reachable yield of any microelectronic circuit manufacturing but can also be used for IC lifetime estimation.

The use of the quaternary semiconductor alloy Ga_xIn_1-xAs_yP_1-y for the development of new electronic, optoelectronic or high speed microwave devices is of great technological interest e.g. in telecommunication. Under certain manufacturing conditions unwanted variations in the chemical composition of these materials can occur, which can be attributed to the existence of a miscibility gap. These decomposition phenomena occur within the nanometer and subnanometer scale. Therefore it is necessary to use characterisation methods of high sensitivity and at the same time highest spatial resolution to investigate independently key parameters such as layer thickness, chemical composition or crystalline structure. The Scanning Transmission Electron Microscope (STEM) is suited for such material analyses since it combines illustrating and analytic characterisation methods together with high spatial resolution. The goal of this work was a comprehensive qualitative and quantitativ e investigation of decomposition in GaxIn1-xAsyP1-y using characterisation techniques like bright-field and Z-contrast imaging as well as electron energy loss spectroscopy (EELS) and convergent beam electron diffraction (CBED), performed in a STEM. For the first time the chemical decomposition process were quantified on the nanometer scale. The course of the decomposition and the predicted expansion of the miscibility gap could be acknowledged in the experiment. Additionally it was shown that by optimising growth parameters (e.g. pressure) of strain compensated superlattices the decomposition process could be inhibited or even stopped. At the same time for the improvement of the evaluation of high resolution Z-contrast images the maximum entropy method (MEM) was applied. Due to the use of the MEM the high resolution Z-contrast images permits the investigation of defect structures and for the first time using a STEM at 100 keV the dumb bells of GaSb was resolved in maximum entropy reconstruction

This paper analyses the transfer of standardized products by FDI between industrial countries, newly industrialized countries and developing countries. One focus of this study is the question whether local entrepreneurs can acquire knowledge as joint venture partners and utilize this knowlegde for an outgoing investment in a third country. This requires that the local entrepreneurs have access to product, production process and management know how. This paper proposses the hypothesis, that the transfer of simple, standardized products can be explained with the catching-up product cycle. In the empirical part, Japanese FDI in Taiwan are compared with Taiwanese FDI in China in the branches electric & electronic and automobile parts. Case studies supplement this research. There two major findings. Taiwanese-Japanese joint ventures are operating successfully in China. The Taiwanese side has acquired at least management know-how in co-operation with the Japanese.