Cold spells in the Nordic Seas during the early Eocene Greenhouse

Abstract The early Eocene (c. 56 - 48 million years ago) experienced some of the highest global temperatures in Earth’s history since the Mesozoic, with no polar ice. Reports of contradictory ice-rafted erratics and cold water glendonites in the higher latitudes have been largely dismissed due to ambiguity of the significance of these purported cold-climate indicators. Here we apply clumped isotope paleothermometry to a traditionally qualitative abiotic proxy, glendonite calcite, to generate quantitative temperature estimates for northern mid-latitude bottom waters. Our data show that the glendonites of the Danish Basin formed in waters below 5 °C, at water depths of &lt;300 m. Such near-freezing temperatures have not previously been reconstructed from proxy data for anywhere on the early Eocene Earth, and these data therefore suggest that regionalised cool episodes punctuated the background warmth of the early Eocene, likely linked to eruptive phases of the North Atlantic Igneous Province.</jats:p

Robust double-ring junction termination extension design for high voltage power semiconductor devices based on 4H-SiC

In this study, a robust double-ring junction-termination-extension (DR-JTE) for highvoltage pn-diodes is presented and analyzed using numerical simulations. As figured out, the DRJTE reduces the electrical field at both, the edge of the single-JTE region and the mesa-transition, respectively. Thereby, due to the reduction of the electrical field, the maximum breakdown voltage is increased to 91.5% of the theoretical, parallel-plane breakdown voltage of 6.5 kV and the maximum acceptable deviation of the optimum implantation dose is twice than that of the single- JTE structure. Furthermore, due to the internal ring, the mesa-transition is shielded from the electrical field and therefore the breakdown voltage is much less affected by the angle of the mesa

Alloying of ohmic contacts to n-type 4H-SiC via laser irradiation

In this study, we present results on alloying nickel as ohmic contact material to n-type 4H-SiC via a continuous wave fiber laser with different laser beam powers and processing times. The laser system exhibits an emitting wavelength of 1070 nm and a beam propagation factor M2 smaller than 1.1. Contact resistance was determined by current-voltage measurement using two- terminal contact resistance method. The results indicate that a laser beam power of at least 100 W is mandatory to initialize contact silicidation. Although the contact resistance is improvable by longer processing times, our experiments outline the much higher impact of laser beam power to contact silicidation compared to processing time. For laser beam powers of 300 W and processing times of 0.5 s a contact resistance of 6.5 comparable to contacts alloyed in a lamp heated furnace at 910 °C for 2 min with a contact resistance of 10.3, was achieved

Analysis of compensation effects in aluminum-implanted 4H-SiC devices

In this work, we analyze compensating defects which are formed after implantation of aluminum (Al) into n-type 4H-SiC epitaxial layers and subsequent thermal annealing. These defects reduce the expected free charge carrier density by 84% for a low doped layer with [Al]impl ≈ 9·1016 cm-3 and by 27 % for a high doped layer with [Al]impl ≈ 2·1019 cm-3. Furthermore, an electrical activation ratio of implanted aluminum ions of 100 % is calculated. The ionization energy of implanted aluminum as measured by Hall effect and admittance spectroscopy ranges from 101 meV to 305 meV depending on the doping concentration

Untersuchung ueber Moeglichkeiten zur Loesung der Messaufgaben des PUREX-Verfahrens mit Hilfe neuartiger Instrumentierungen Abschlussbericht

With 191 refs., 14 tabs., 41 figs.SIGLECopy held by UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

European Conference on Silicon Carbide and Related Materials

http://www.ecscrm2006.org/ Wide-band gap semiconductors such as SiC and GaN have become the materials of choice for future developments in high power and temperature environments. In recent years, exciting new products using SiC in particular have come to the market and the future looks bright for these materials. The European Conference on Silicon Carbide and Related Materials is well-established as Europe's leading conference on this topic . Submitted abstracts are invited in all subject areas related to Silicon Carbide and Related Materials. In particular, abstracts are welcomed on the following topics: Materials Growth (Bulk and Epitaxy) Materials Characterization and Theory Device Processing Device Optimization/Performanc