Low pressure chemical vapor deposition of polysilicon

The low pressure chemical vapor deposition of polycrystalline silicon was studied to define the controlling process parameters and the requirements for commercial implementation. Silane and silane-nitrogen mixtures were utilized as source gases in a tubular reactor containing parallel disk substrates oriented with surface normals in the direction of flow. The results of the study showed that the deposition reaction is surface kinetic reaction controlled over the range of temperature studied, 600 to 700/sup 0/C, that the reaction is first order with respect to silane, and with an activation energy of 1.33 x 10/sup 5/ J/g mole. A gradient in temperature along the reactor tube is sufficient to compensate for reactant depletion and to produce a uniform deposition rate

Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo

Meeting Abstracts: Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo Clearwater Beach, FL, USA. 9-11 June 201

Quantification of land-atmosphere exchanges of water, energy and carbon dioxide in space and time over the heterogeneous Barrax site

To advance our understanding of land-atmosphere exchanges of water, energy and carbon dioxide (CO2) in space and time over heterogeneous land surfaces, two intensive field campaigns were carried out at the Barrax agricultural test site in Spain during 12-21 July 2004 (SPARC 2004) and 8-14 July 2005 (SEN2FLEX 2005) involving multiple field, satellite and airborne instruments for characterizing the state of the atmosphere, the vegetation and the soil from the visible to the microwave range of the spectrum. Part of the experimental area is a core site of area 25 km2, within which numerous crops are grown, on both irrigated and dry land, alongside fields of bare soil. The campaigns were carried out in the framework of the Earth Observation Envelope Programme of the European Space Agency (ESA) with the aim of supporting geophysical algorithm development, calibration/validation and the simulation of future spaceborne Earth Observation missions. Both campaigns were also contributions to the EU 6FP EAGLE Project. The emphasis of this contribution is on the in situ measurements of land-atmosphere exchanges of water, energy and CO2 as well as the thermal dynamic states of the atmosphere, the soil and the vegetation. Preliminary analysis and interpretation of the measurements are presented. These two data sets are open to the scientific community for collaborative investigations