Автоматизация построения геолого-технического наряда на строительство скважин

Tunnel junctions of Co(10 nm)/AlOx (nominally 2 nm)/Co(20 nm) have been prepared by molecular beam epitaxy applying a shadow mask technique in conjunction with an UV light-assisted oxidation process of the AlOx barrier. The quality of the AlOx barrier has been proven by x-ray photoelectron spectroscopy and temperature dependent tunneling magnetoresistance (TMR) measurements. Optimum-oxidized tunnel junctions show a TMR of 20% at 285 K and up to 36% at 100 K. At 285 K the TMR values as a function of oxidation time are not symmetric about the optimum time. For underoxidized junctions the TMR is reduced more strongly than for overoxidized junctions. The temperature dependence of the junction s resistance is a clear and reliable indicator whether pinholes (or imperfections)contribute to the conduction across the barrier

Friction stir welding Ti-al alloys with ultrasonic impact

High performance and reduced weight and cost are gaining importance in the aviation industry. There are different approaches to meet these requirements. In this study, titanium and aluminum alloys were welded using friction stir welding. The samples were divided into two groups, one of which was welded using ultrasound. Studies have shown that the strength of samples is influenced by many factors that are usually not taken into account. For example, the complexity of the interface between dissimilar materials and its roughness. It was found that the application of ultrasound during welding often increases the complexity of the interface and decreases its roughness, which generally leads to strengthening. This effect can neutralize the increase in the volume fraction of intermetallic compounds during the intensification of the welding process. The final strength consists of the number of defects, the volume fraction of intermetallics and the complexity of the interface

Energieabfuhr in Fusionsplasmen durch Linienstrahlung von Verunreinigungen

Strahlungskühlung mittels Verunreinigungen stellt eine mögliche Lösung des Wänneauskopplungsproblems in einem Fusionsreaktor dar. Es ist ein zur Zeit hochaktuelles Thema, an dem weltweit in den Fusionslabors gearbeitet wird. Die erstmalige Realisierung der quasi-stationären Strahlungskühlung bei hohen Heizleistungsdichten in einem Tokamak gelang am Tokamak TEXTOR in Jülich. In der vorliegenden Arbeit soll eine Zusammenfassung dieser Entwicklungen und der daraus abgeleiteten Prinzipien gegeben werden. Dazu zählen die Vorläuferexperimente mit niedrigen Heizleistungen, aus denen heraus sich später das Regelsystem zur Strahlungskühlung bei hohen Heizleistungen entwickelte. Das Resume der wichtigsten Prozesse und Zusammenhänge steht im Vordergrund. Aktuelle Ergebnisse zu noch nicht abgeschlossenen Fragen, z.B. zur Kompatibilität mit Energieeinschlußszenarien und Divertorexperimente, werden nur kurz gestreift. Allerdings wird auch anhand grundsätzlicher Überlegungen deutlich gemacht werden, daß letztendlich nur eine integrale Lösung Erfolg haben kann; d.h., Energieeinschluß, Teilchenabfuhr und Materialfragen müssen mit in das Szenario zur Strahlungskühlung einbezogen werden...

Radiation control in a limiter tokamak

The requirements for radiation cooling in a tokamak are discussed and experimental evidence for a plasma with a cold radiating boundary - the detached plasma - is presented as an example. The radiation characteristics is analyzed and, in particular, the non-coronal conditions at the plasma boundary are considered by introducing the radiation potential in order to express the radiation in terms of impurity fluxes rather than in densities. The possibilities for radiation control by intrinsic and injected impurities are examined and some experimental examples are presented

Temperature-dependent magnetoresistance of magnetic tunnel junctions with ultraviolet light-assisted oxidized barriers

Co(10 nm)/AlOx(nominally 2 nm)/Co(20 nm) tunnel junctions have been prepared under ultrahigh vacuum conditions applying a shadow mask technique. An ultraviolet light-assisted oxidation process of the AlOx barrier has been optimized by in situ x-ray photoelectron spectroscopy, in conjunction with temperature-dependent tunneling magnetoresistance measurements. Optimum-oxidized tunnel junctions show a magnetoresistance of 20% at 285 K, and up to 38% at 100 K. For under-oxidized samples, with a remaining Al layer between the Co bottom electrode and the AlOx barrier, the tunneling magnetoresistance decreases more rapidly with increasing temperature than observed for the over-oxidized samples. The resistance × area product of optimum-oxidized tunneling junctions exhibits a minimum, and increases for under- and over-oxidized samples

Western Star, 1914-02-18

The Western Star began publication on Newfoundland's west coast on 4 April 1900, appearing weekly with brief semiweekly periods up to 1952, when it became a daily. As of 17 April 2019 it continues as a free weekly community paper