Einfluß der Spänebehandlung auf die Oberflächenqualität von Holzspanplatten

Ohne Zusammenfassung Die Firma WIRUS-werke W. Ruhenstroth GmbH, Gütersloh. stelite das Deckschichtmaterial zur Verfügung. Herr Dr. A. Burmester. BAM-Berlin, erm?glichte die Behandlung einiger Sp?nechargen nach dem FWD-Verfahren. Herr Ing. grad. J. Schwenzien, BAM-Laboratorium 5.24, fertigte die Tastschriebe. Die Verfasset m?chten auch an dieser Stelle allen Genannten für die erwiesene Unterstützung danken     

Zur Theorie der Trennfestigkeit metallischer Werkstoffe

Begriff der Trennfestigkeit. Aufstellung von Festigkeitsbedingungen für homogene isotrope Stoffe. Darstellung der Festigkeitsgrenzen im Hencky-Schaubild. Vieldeutigkeit der Mehrachsigkeitsziffern. Eindeutige Kennzeichnung der Form eines Spannungszustandes. Ermittlung der Hauptspannungen für reine Zugspannungszustände. Plastizitätsgrenze und kritischer Räumlichkeitsgrad. Zahlenbeispiel für den Baustahl St 42-3. Anwendung auf Kerbspannungen.     

Spontaneous lifetime and quantum efficiency in light emittingdiodes affected by a close metal mirror

The spontaneous lifetime and quantum efficiencies of dipoles placed close to a metal mirror are calculated. The importance of these effects is demonstrated in the recent experimental work on InGaAs-GaAs quantum-well light-emitting diodes (QW LEDs) in which the modulations rates were varied from 0.8 GHz to 1.4 GHz through the placement of a QW next to a Ag mirror (D.G. Deppe et al., 1990). Classical energy transfer theory is used to treat the spontaneous radiation of a QW in a semiconductor system. The spontaneous radiative lifetime and internal quantum efficiency are strongly affected by the location of the QW, which confines the dipoles, by the orientation of the dipole in the well, by the metal reflector material, and by the metal mirror thickness. In general, the internal quantum efficiency decreases when the dipole is closer to the metal, because of the nonradiative energy transfer from the dipole to the absorptive metal. The overall effect of closely spaced metal mirrors on the measurable external quantum efficiency, which is important for fast light emitting diode design, is presented     

Fabrication of high-packing-density vertical cavity surface-emitting laser arrays using selective oxidation

We describe the nearly-planar processing of two-dimensional vertical cavity laser arrays based on the selective conversion of AlAs to Al/sub x/O/sub y/. The individual lasers of 8/spl times/8 and 2/spl times/2 arrays are defined by native Al/sub x/O/sub y/ to achieve 4-/spl mu/m square active regions on 12-/spl mu/m center-to-center spacings. Interelement thermal coupling is characterized along with the optical mode structure.     

Die Schlackenbildung beim Aufblasen von Sauerstoff mit Feinkalk auf phosphorreiches Roheisen

Gefügeuntersuchungen an Schlackenproben, die während des Blasens einem 18-t-?LD-AC?-Konverter entnommen wurden. Die ?Schlackenbildung? beim Blasen ohne und mit Vorverlegung der Entphosphorung vor die Entkohlung. Hinweise für das Schäumen der Schlacken.     

Microbial production,structure elucidation and bioconversion of sophorose lipids

Cultivation of Torulopsis bombicola ATCC 22214 on a mixture of glucose and oleic acid (A) or oleic acid alone (B) produced large amounts of sophorose lipids. In the case of A, 38 g/1 of crude product were finally isolated; fermentation B led to 77 g/1. After separation by MPLC and TLC, six glycolipids were obtained and identified by NMR and fast atom bombardment-mass spectrometry (FAB-MS). In general, a 17-hydroxyocta-decanoic acid at the C-1’ -position and acetate groups at the C-6’ -and C-6’ -positions of sophorose were found as substituents in the lactone and acidic forms of these lipids. The composition of product from A was as follows: 62% of sophorolipid 1’,4’ -lactone 6’ ,6’ -diacetate (SL-1), 4% of sophorolipid 1’,4’-lactone 6’-monoacetate (SL-2), 4% of sophorolipid 1’,4 ’-lactone (SL-3), 4% of sophorolipid 1’,6’-and l’,6’-lactones (SL-4a,b), 4% of sophorolipid 6’-monoacetate acid (SL-5), 4% of sophorolipid acid (SL-6) and finally 17% of other lipids. In B, the principal lactone (40%) had a double bond in the fatty acid moiety; the other components were identical with the above products. Yields of 13% SL-2 and of 35% lipids containing no carbohydrate were significant. SL-1 was deacetylated to SL-3 (yield: 25-307c) using acetyl-esterase in a two-phase system (cyclohexane/water). To whom correspondence should be addressed.