Über die Grenzfläche der Strahlensysteme,die durch Bewegung eines Strahlenbüschels entstehen

Ohne Zusammenfassung     

Darstellung von Pentadecylalkohol aus Palmitinsäure

Ohne ZusammenfassungZum Schlusse drängt es mich, meinem hochverehrten Lehrer Herrn Hofrath Professor Dr. Ad. Lieben, sowie dem Herrn Dr. K. Natterer für ihre freundliche Unterstützung mit Rath und That den wärmsten Dank auszusprechen.     

Efficient synthesis of [3H]-sanglifehrin A via selective oxidation/reduction of alcohols at C31 and C35

[Reaction: see text]. Sanglifehrin A is a novel complex natural product showing strong immunosuppressive activity and remarkably high affinity for cyclophilin A. To assess its pharmacokinetic properties in vivo, an efficient synthetic route was developed to introduce a tritium label in position C35 of sangliferin A via an oxidation/reduction strategy. The synthetic approach is particularly attractive, because the C35-oxo intermediate 7 is available in good yield on large scale and the reducing agent, lithium tri-sec-butylborotritide, is readily available. An attempt to apply a similar strategy to the alcohol in position C31 led primarily to C31-epi-hydroxy sanglifehrin A under a variety of conditions.     

Improvement of Injection-Locked VCSELs for Analog and Digital Communication Systems

VCSEL Injection locking is demonstrated to increase laser bandwidth and reduce non-linearity and chirp.All these properties enhance analog and digital modulation performance.     

Substitution reactions with [ReBr(2)(CO)(2)(NCCH(3))(2)](-): a convenient route to complexes with the cis-[Re(CO)(2)](+) core

Water- and air-stable complexes comprising the cis-[Re(CO)(2)](+) core can be synthesized from the (Et(4)N)[ReBr(2)(NCCH(3))(2)(CO)(2)] precursor . Complex showed distinctly different chemical and electronic behaviour compared to [ReBr(3)(CO)(3)](2-). Substituting the two bromides in with imidazole-like ligands or alpha,alpha'-diimines gave new complexes with potential applications in bioinorganic chemistry and photochemistry. The two acetonitrile ligands are very stably bound and could not be replaced. Under CO pressure, the uncommon complex mer-[ReBr(NCCH(3))(2)(CO)(3)] was formed from . The reaction of with the tetradentate ligand bis(2-pyridylmethyl)glycine (BPG) finally induced a four fold substitution at the metal center to form a [Re(CO)(2)(L(4))](+)-type complex.     

A hyperbolic surface with a square grid net

We prove the existence of a hyperbolic surface spread over the sphere for which the projection map has all its singular values on the extended real line and such that the preimage of the extended real line under the projection map is homeomorphic to the square grid in the plane. This answers a question raised by è. B. Vinberg. Supported by the Alexander von Humboldt Foundation. Supported by NSF grants DMS-0400636, DMS-0244421, and DMS-0244547.     

Continuous proton spectra emitted in 3He and deuteron induced reactions

A study of the energy and angular distributions of protons emitted in ³He induced reactions was undertaken at an incident energy of 25.6 MeV. An analysis in the framework of the pre-equilibrium hybrid model did not succeed in explaining the overall behaviour of proton spectra; a contribution due to a break-up or a double stripping of the incident particle has to be taken into account. An attempt was made to account for these processes by performing a phase space calculation. This formulation was firstly tried in the case of deuteron induced reactions for which a break-up mechanism has already been confirmed in continuous proton spectra. The calculation extended to the case of ³He induced reactions showed that a double stripping mechanism could explain the observed distribution.