Electrophoretic deposition of gradated oxidation resistant coatings on tantalum-10 tungsten alloy

Material selection and electrophoretic deposition studies of high temperature oxidation resistant coatings on tantalum-10 tungsten allo

Development of oxidation resistant coatings for use above 3500 deg F

Physical property evaluation of oxidation resistant coating materials for high temperature protection of tantalum-base alloy

Endoskopische Diagnostik und Therapie der gastrointestinalen Blutung

Zusammenfassung: Die gastrointestinale Blutung stellt unveränderte einen der häufigsten medizinischen Notfälle dar. Obwohl die Mortalität in den letzten Jahren durch Verbesserung der endoskopischen Diagnostik und Therapie leicht gesenkt werden konnte, liegt sie immer noch bei 15%. Zahlreiche Publikationen zu neuen Techniken und Therapiestrategien zeigen kontroverse Ergebnisse, so dass der Endoskopiker in seinen Therapienentscheidungen häufig auf seine persönliche Erfahrung angewiesen ist. Daher werden in diesem Artikel, neben einer neuerer Literaturanalyse zu diesem Thema, Therapieempfehlungen für die Praxis aus dem eigenen Erfahrungsbereich gegebe

Non-linear exciton spin-splitting in single InAs/GaAs self-assembled quantum structures in ultrahigh magnetic fields

We report on the magnetic field dispersion of the exciton spin-splitting and diamagnetic shift in single InAs/GaAs quantum dots (QDs) and dot molecules (QDMs) up to $B$ = 28 T. Only for systems with strong geometric confinement, the dispersions can be well described by simple field dependencies, while for dots with weaker confinement considerable deviations are observed: most importantly, in the high field limit the spin-splitting shows a non-linear dependence on $B$, clearly indicating light hole admixtures to the valence band ground state

Relativistic photoelectron spectra in the ionization of atoms by elliptically polarized light

Relativistic tunnel ionization of atoms by intense, elliptically polarized light is considered. The relativistic version of the Landau-Dykhne formula is employed. The general analytical expression is obtained for the relativistic photoelectron spectra. The most probable angle of electron emission, the angular distribution near this angle, the position of the maximum and the width of the energy spectrum are calculated. In the weak field limit we obtain the familiar non-relativistic results. For the case of circular polarization our analytical results are in agreement with recent derivations of Krainov [V.P. Krainov, J. Phys. B, {\bf 32}, 1607 (1999)].Comment: 8 pages, 2 figures, accepted for publication in Journal of Physics

Correlation energy of an electron gas in strong magnetic fields at high densities

The high-density electron gas in a strong magnetic field B and at zero temperature is investigated. The quantum strong-field limit is considered in which only the lowest Landau level is occupied. It is shown that the perturbation series of the ground-state energy can be represented in analogy to the Gell-Mann Brueckner expression of the ground-state energy of the field-free electron gas. The role of the expansion parameter is taken by r_B= (2/3 \pi^2) (B/m^2) (\hbar r_s /e)^3 instead of the field-free Gell-Mann Brueckner parameter r_s. The perturbation series is given exactly up to o(r_B) for the case of a small filling factor for the lowest Landau level.Comment: 10 pages, Accepted for publication in Phys.Rev.

Biological removal of fine-grained lithogenic particles from a large river plume

The pelagic tunicate, Oikopleura dioica, feeds by non-selectively filtering particles in the size range of 0.2–20 μm. In the northern Gulf of Mexico, particulate matter in this size range contains large amounts of fine-grained lithogenic material because of the influence of the Mississippi River. During May 1992, O. dioica populations filtered between 2 and 44% (mean = 20%) of the upper 5 m each day. The filtered lithogenic particles either remain in the oikopleurid house or are defecated in fecal pellets which have high sinking velocities. Either way, the larvacean populations significantly alter the fates of fine-grained lithogenic particles in these waters and thereby enhance light penetration. The widespread occurrence of oikopleurids in coastal regions of temperate and subtropical oceans suggests they could have a significant influence on the fates of fine-grained lithogenic particles in discharge plumes of many of the world\u27s large, sediment-laden rivers