Über Fehler von Elektronenbildern

Zusammenfassung Die sogenannten Fehler dritter Ordnung eines Elektronenbildes werden mit Hilfe der einfachen Hamiltonschen charakteristischen Funktion (des Punkteikonals) hergeleitet. Man braucht dazu nur diese Funktion für ein reales Bündel nach Taylor bis zu Gliedern vierter Ordnung zu entwickeln und sie mit der entsprechenden Entwicklung für ein ideales Punktbündel zu vergleichen. Wird die Differenz beider nach den Blendenkoordinaten differenziert, so gibt das Ergebnis sofort die gesuchten Fehler an. Diese Herleitung setzt voraus, daß man die charakteristische Funktion und ihre Beziehung zur Optik und Mechanik kennt. Aus dem Grunde wird in einem besonderen Abschnitt an das Fermatsche und an das Maupertiussche Prinzip und an die Eigenschaften der charakteristischen Funktion erinnert. Für die notwendige Erweiterung beim magnetischen Feld wird ein einfacher Beweis gegeben. Die Fehler selbst werden sodann eingehend diskutiert, wobei gelegentlich neben der analytischen Behandlung auch die geometrische herangezogen wird.     

Inspection errors and statistical quality control: A survey

The presence of inspection or measurement errors may seriously affect the level of protection afforded by a statistical quality control procedure. In order to adequately compensate for such errors, the quality control analyst must be able to model their occurrence and incorporate them into the design of the procedure. This paper surveys the current state of knowledge in this area, points out the shortcomings of the present approaches and suggests future lines of investigation.     

Stresses in hard coating due to a rigid spherical indenter on a layered elastic half-space

The axisymmetrical contact problem of elasticity connected with an indentation of a rigid spherical indenter in an elastic semi-space covered by an elastic layer is considered. Stress tensor components in interior points of the non-homogeneous half-space by numerical calculation of some integrals was obtained. Detailed analysis of the maximal tensile stress distributions and Huber-von Mises reduced stress distributions produced by contact pressure is presented. The dependence between these stresses and the ratio between the layer thickness and contact area width is explored. The obtained results for stresses are compared with results obtained for half-space loaded by the Hertz pressure.     

Optical Stabilization of Waveguide Amplifiers for WDM Ring Network With Recirculating Optical Power

We demonstrate an all-optical wavelength-division-multiplexing ring network immune to transients based on individual optically gain clamped waveguide amplifiers. The ring network is compared to a similar point-to-point configuration to quantify the effect of recirculating amplifier noise. In the results, we notice that the optical stabilization is strong enough to overcome the effect of accumulated amplifier noise over the entire transmission bandwidth, and no lasing or chaotic behavior occurs. In addition, due to the independent amplifier stabilization, the network has shown to be robust even in the case of failure and restoration. We prove that the obtained results are scalable with the amplifier number. All results are also applicable to fiber-based amplifiers.     

Effect of lattice disorder and strain on TC in sputtered “Nb3Ge” thin films

Disorder and strain introduced into sputtered “Nb₃Ge” films by mechanical polishing slightly lowers the onset temperature and/or very markedly broadens the width of the superconducting transition. The structural damage is reversible and annealing restores the superconducting behavior of the film very nearly to its initial state.