959 resultados para Planejamento Box-Behnken


Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this work we employed a hybrid method, combining RF-magnetron sputtering with evaporation, for the deposition of tailor made metallic precursors, with varying number of Zn/Sn/Cu (ZTC) periods and compared two approaches to sulphurization. Two series of samples with 1×, 2× and 4× ZTC periods have been prepared. One series of precursors was sulphurized in a tubular furnace directly exposed to a sulphur vapour and N2+5% H2 flux at a pressure of 5.0×10+4 Pa. A second series of identical precursors was sulphurized in the same furnace but inside a graphite box where sulphur pellets have been evaporated again in the presence of N2+5% H2 and at the same pressure as for the sulphur flux experiments. The morphological and chemical analyses revealed a small grain structure but good average composition for all three films sulphurized in the graphite box. As for the three films sulphurized in sulphur flux grain growth was seen with the increase of the number of ZTC periods whilst, in terms of composition, they were slightly Zn poor. The films' crystal structure showed that Cu2ZnSnS4 is the dominant phase. However, in the case of the sulphur flux films SnS2 was also detected. Photoluminescence spectroscopy studies showed an asymmetric broad band emission whichoccurs in the range of 1–1.5 eV. Clearly the radiative recombination efficiency is higher in the series of samples sulphurized in sulphur flux. We have found that sulphurization in sulphur flux leads to better film morphology than when the process is carried out in a graphite box in similar thermodynamic conditions. Solar cells have been prepared and characterized showing a correlation between improved film morphology and cell performance. The best cells achieved an efficiency of 2.4%.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The box contained the chocolate elephant.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This pewter hinged flip-top box is 9 cm x 7 cm and has a 2 cm depth. It contains lit and unlit matches. It is worn and slightly dented.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tin box with the title “Waldmeister zur Bowle, Woodruff” on it, 10 cm x 16 cm. The box is from Julius Schade and Co., German Army and Navy Contractors, Leipzig-Lindenau, Germany. This box contains dried woodruff leaves. Accompanying this box of woodruff is a handwritten recipe for woodruff brew, n.d.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The topology as the product set with a base chosen as all products of open sets in the individual spaces. This topology is known as box topology. The main objective of this study is to extend the concept of box products to fuzzy box products and to obtain some results regarding them. Owing to the fact that box products have plenty of applications in uniform and covering properties, here made an attempt to explore some inter relations of fuzzy uniform properties and fuzzy covering properties in fuzzy box products. Even though the main focus is on fuzzy box products, some brief sketches regarding hereditarily fuzzy normal spaces and fuzzy nabla product is also provided. The main results obtained include characterization of fuzzy Hausdroffness and fuzzy regularity of box products of fuzzy topological spaces. The investigation of the completeness of fuzzy uniformities in fuzzy box products proved that a fuzzy box product of spaces is fuzzy topologically complete if each co-ordinate space is fuzzy topologically complete. The thesis also prove that the fuzzy box product of a family of fuzzy α-paracompact spaces is fuzzy topologically complete. In Fuzzy box product of hereditarily fuzzy normal spaces, the main result obtained is that if a fuzzy box product of spaces is hereditarily fuzzy normal ,then every countable subset of it is fuzzy closed. It also deals with the notion of fuzzy nabla product of spaces which is a quotient of fuzzy box product. Here the study deals the relation connecting fuzzy box product and fuzzy nabla product

Relevância:

20.00% 20.00%

Publicador:

Resumo:

These Java Applets help to illustrate some of the difficult to grasp concepts of quantum mechanics. To run this Applet, use the 'Download as zip files' option. Make sure you extract the files first, then double click on the .html file to run the Applet. These are released as open access resources for the purpose of testing, and are to be deployed at the users own risk. Please report any errors you find.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

These Java Applets help to illustrate some of the difficult to grasp concepts of quantum mechanics. To run this Applet, use the 'Download as zip files' option. Make sure you extract the files first, then double click on the .html file to run the Applet. These are released as open access resources for the purpose of testing, and are to be deployed at the users own risk.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

INFO2009, Coursework 2, Green ICT/IT