F-Gruppen

Ohne Zusammenfassung     

Über die globale Konvergenz von Variable-Metrik-Verfahren mit nicht-exakter Schrittweitenbestimmung

Summary We consider unconstrained minimization problems and the application of the Broyden-Fletcher-Goldfarb-Shanno variable metric algorithm without exact line searches. For a certain class of step functions the global convergence of this method is proven, generalizing a result given by Powell. Furthermore some remarks are made concerning the superlinear convergence of this particular variable metric algorithm.

     

β-oxa-γ,δ-enones,II. Rearrangement and intramolecular cycloaddition of 1-cyclopentenyloxy-2-propanone.

The title compound $\text{1}$ undergoes an intramolecular photocycloaddition reaction to yield the bis-oxetane $\text{2}$ and a formal 1,3-shift to yield the 1,4-diketone 3. This work reveals a novel aspect of the photochemistry of β-oxa-γ,δ-enones.     

Optimized preamplifiers for pyroelectric detectors

The performance of pyroelectric detectors largely depends on the design of the preamplifier. In this paper the amplifier parameters affecting detector overall performance will be discussed and some design details improving rise time without sacrificing noise figure will be described. Results achieved with two prototype amplifiers will be presented.