Comparison of High Q microresonators operating on a thin plate mode : the Lamé-mode

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Kalkiges Nannoplankton aus dem Unter-Hauterivium bis Unter-Barrêmium der Tongrube (Unter-Kreide, NW-Deutschland)

41 samples which have been collected from the Lower Cretaceous section Moorberg/Sarstedt (Lower Hauterivian-Lower Barremian) have been investigated for calcareous Nannoplankton. About 4500 coccoliths have been measured, most of which are determinated as Biscutum constans, Bidiscus rotatorius, Corollithion geometricum, Cyclagelosphaera margereli, Parhabdolithus asper and Sollasites horticus. These dates are evaluated and partly graphically represented. Within the paleontological part 4 5 species are described and partly illustrated by photos and drawings. 2 new species (Chiastozygus octiformis and Chiastozygus tripes) are introduced, while one genus and one species are emended. Based on 18350 countered specimens the relative quantity of 68 species is shown, 15 of which got stratigraphical signifi- cance for NW-Germany and possible further around. According to the calcareous Nannoplankton the connection of the "boreal realm" and the Tethys should have been interrupted already in the lowermost Upper Hauterivian.

Revestimentos a base de Ta/Al2O3 produzidos por aspersão térmica sobre substrato metálico

Metal substrates were coated by thermal spraying plasma torch, they were positioned at a distance of 4 and 5 cm from the nozzle exit of the plasma jet. The starting materials were used for deposition of tantalum oxide powder and aluminium. These two materials were mixed and ground into high-energy mill, then immersed in the torch for the production of alumina coating infused with particles of tantalum with nano and micrometric size. The spraying equipment used is a plasma torch arc not transferred, which operating in the range of 250 A and 80 V, was able to produce enough heat to ignite aluminothermic between Ta2O5 and aluminum. Upon reaching the plasma jet, the mixing powders react with the heat of the blaze, which provides sufficient energy for melting aluminum particles. This energy is transferred through mechanisms of self-propagating to the oxide, beginning a reduction reaction, which then hits on the surface of the substrate and forms a coating on which a composite is formed by a junction metal - ceramic (Ta +Al2O3). The phases and quantification of each were obtained respectively by X-ray diffraction and the Rietveld method. Morphology by scanning electron microscopy and chemical analysis by energy dispersive spectroscopy EDS. It was also performed measurements of the substrate roughness, Vickers microhardness measurements in sprays and determination of the electron temperature of the plasma jet by optical emission spectroscopy EEO. The results confirmed the expectation generated around the end product of spraying the mixture Ta2O5 + Al, both in the formation of nano-sized particles and in their final form. The electron excitation temperature was consistent with the purpose of work, in addition, the thermodynamic temperature was efficient for the reduction process of Ta2O5. The electron excitation temperature showed values of 3000, 4500 and 8000 K for flows10, 20 and 30 l / min respectively, these values were taken at the nozzle exit of the plasma jet. The thermodynamic temperature around 1200 ° C, was effective in the reduction process of Ta2O5

Optimization of quantum states for signaling across an arbitrary qubit noise channel with minimum-error detection

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El neorruralismo: Una nueva mirada al desarrollo rural de Chile

Introducción El sector silvoagropecuario chileno aporta cerca del 7% de producto interno bruto del país, cerca de 4500 millones de dólares anualmente. Esta contribución disminuye aceleradamente cada año en términos porcentuales, debido al crecimiento de la economía en su conjunto y al de algunos sectores productivos como el comercio, la industria y los servicios (ODEPA 2000)…

Tarrazú y Orosí: Cambios en la cadena de comercialización del café y estrategias ante la liberalización del mercado, 1989-2006

ResumenEl presente artículo versa sobre los cambios que enfrentó la cadena de comercialización del café de Tarrazú y Orosi después de la liberalización del mercado, así como las estrategias implementadas por los beneficiadores y exportadores del grano para enfrentar las coyunturas críticas suscitadas por la ruptura del Acuerdo Internacional del Café. En este trabajo se aborda las causas del mercado libre y sus repercusiones en la cadena del café nacional, la dinámica de los eslabones del beneficiado y la exportación en cada región de estudio y las respuestas de los actores ante la crisis en los mercados.AbstractThis article focuses on the changes the Orosi and Tarrazú coffee marketing system had to deal with after the markets liberalization, and the strategies implemented by the processors and exporters of the coffee bean in order to tackle the critical situations that arose from the rupture of the International Coffee Agreement. This paper addresses the object of the free market and its impact on the domestic coffee-producing system, the dynamics of the coffee-processing and export structures in each region under study, and the key players response to the market crisis.