Über das Glykol und Aldol aus Isobutyr- und Isovaleraldehyd

Ohne ZusammenfassungAn dieser Stelle erfüllen wir mit grosser Freude die angenehme Pflicht, unserem hochverehrten Lehrer, Herrn Hof-rath Professor Dr. Adolf Lieben, für vielfache Anregung und lebhaftes Interesse, welches er unserer Arbeit entgegenbrachte, unseren tiefgefühlten Dank auszusprechen.     

On the theory of the shear-induced isotropic-to-nematic phase transition of side chain liquid-crystalline polymers

The shear-induced isotropic-to-nematic phase transition of side chain liquid-crystalline polymers is studied theoretically. A modification of the previous models of main-chain liquid crystals to the case of side chain liquid-crystalline polymers is proposed. Orientational and rheological properties of the model are studied in plane-shear flow. Predictions of the present model agree qualitatively with experimental results (Pujolle-Robic, Noirez in Nature 409:167, 2001).     

Über das Aldol und Glykol aus Isobutyr- und Acetaldehyd

Ohne Zusammenfassung     

Electron subband structure and controlled valley splitting in silicon thin-body SOI FETs: Two-band k · p theory and beyond

We use a two-band k · p Hamiltonian to describe the subband structure in strained silicon thin films. The model describes the dependence of the transversal effective mass on strain and film thickness. However, it is found that the two-band k · p model is unable to describe recently observed large valley splitting. Therefore a generalization of the model is necessary. To go beyond the k · p theory, an auxiliary tight-binding model defined on a lattice of sites containing two localized orbitals is introduced in such a way that it reproduces the bulk dispersion obtained from the two-band k · p model. Corresponding dispersion relations including strain are obtained. We discuss an alternative mechanism to create and control the valley splitting by applying shear strain. The valley splitting increases with increased shear strain and decreasing film thickness and can be larger than the spin splitting. This makes silicon-based quantum devices promising for future applications in quantum computing.     

Untersuchungen über die natürlichen Gleichungen krummer Flächen

Ohne Zusammenfassung     

Untersuchung von Bier, Bierroh- und Zwischenerzeugnissen

Ohne Zusammenfassung     

Stereoselektive Synthesen von Taxan-Derivaten

Stereoselective Synthesis of Taxane Derivatives Substituted racemic 4,8,12-trinortaxanes were prepared stereoselectively in several steps from the dienone 10 . A variant of the de Mayo reaction with bicyclononenones 4 and cyclohexen produced the desired configuration at C(8) of the taxane framework. Retro-aldol cleavage of the tetracycle 5 led to the taxane skeleton 6 . Stereoselective reduction followed by treatment with base afforded 7b . Hydrolysis of the acetal group and further reduction yielded 9 in which the relative configuration corresponds to the one of the natural products.