Longitudinal RF excitation of carbon dioxide lasers

Longitudinal RF excitation of CO₂ — Lasers at relatively low radio frequencies in the 100 to 200 kHz range permits an efficient AC to RF conversion in the power supply while maintaining all the advantages of RF excited lasers. Existing tube designs for DC excitations can be easily modified, and peripheral circuitry like laser stabilizers remain useable too. Experimental results for a prototype laser are given.     

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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.