6,508 research outputs found
Photovoltaic properties of close-space sublimated CdTe solar cells
No full textCdS/CdTe solar cells were fabricated by close-space sublimation with a screen-printed Te-rich CdTe source and their photovoltaic properties were investigated by varying the substrate temperature, cell area, and thicknesses of CdTe and ITO layers. The resistivity of CdTe layers employed in this study was 3 x 10(4) Omega cm. The optimum substrate temperature and thickness for CdTe deposition were 600 degrees C and 5 mu m, respectively. The CdTe bulk resistance degraded the cell performance above 6 mu m. As the cell area increased the V-oc remained almost constant, while the J(ae) and FF were strongly degraded because of the increase of the lateral resistance of the ITO layer. The optimum thickness of the ITO layer in this study was 300-450 nm. In this experiment we obtained an efficiency of 9.4% in the 0.5 cm(2) cells. The series resistance of the cell should be further reduced to increase the fill factor and improve the efficiency. (C) 1998 Elsevier Science Ltd. All rights reserved
A concurrent B-link-tree algorithm using a cooperative locking protocol
No full textWe present a new concurrent B-link-tree algorithm that provides a concurrent tree restructuring mechanism for handling underflow nodes as well as overflow nodes. Our algorithm does not require any lock for downward searching and preserves bottom-up tree restructuring without deadlock. To this end, we develop a new locking mechanism for inserters and deleters and a node update rule that preserves the semantical tree consistency during tree restructuring. Our analytical experiment shows that the overhead of additional disk I/O is acceptable
VARIABLE TARGET VALUE SUBGRADIENT METHOD
No full textPolyak's subgradient algorithm for nondifferentiable optimization problems requires prior knowledge of the optimal value of the objective function to find an optimal solution. In this paper we extend the convergence properties of the Polyak's subgradient algorithm with a fixed target value to a more general case with variable target values. Then a target value updating scheme is provided which finds an optimal solution without prior knowledge of the optimal objective value. The convergence proof of the scheme is provided and computational results of the scheme are reported
Simultaneous Segmentation, Estimation and Analysis of Articulated Motion from Dense Point Cloud Sequence
No full textFabrication of CuInSe2 films and solar cells by the sequential evaporation of In2Se3 and Cu2Se binary compounds
No full textCu2Se/InxSe(x approximate to 1) double layers were prepared by sequentially evaporating In2Se3 and Cu,Se binary compounds at room temperature on glass or Mo-coated glass substrates and CuInSe2 films were formed by annealing them in a Se atmosphere at 550 degreesC in the same vacuum chamber. The InxSe thickness was fixed at 1 mum and the Cu2Se thickness was varied from 0.2 to 0.5 mum. The CuInSe2 films were single phase and the compositions were Cu-rich when the Cu, Se thickness was above 0.35 mum. And then, a thin CuIn3Se5 layer was formed on the top of the CuInSe2 film by co-evaporating In2Se3 and Se at 550 degreesC. When the thickness of CuIn3Se5 layer was about 150nm. the CuInSe2 cell showed the active area efficiency of 5.4% with V-oc = 286 mV, J(sc) = 36 mA/cm(2) and FF = 0.52. As the CuIn3Se5 thickness increased further, the efficiency decreased. (C) 2001 Elsevier Science B.V. All rights reserved
ELECTRICAL-PROPERTIES OF CDTE-FILMS PREPARED BY CLOSE-SPACED SUBLIMATION WITH SCREEN-PRINTED SOURCE LAYERS
No full textCdTe films have been deposited by a close-spaced sublimation process with screen-printed CdTe layers as a new source. The source-layers were fabricated by screen printing and sintering slurries consisting of propylene glycol, CdCl2 and either CdTe powder or (Cd+Te) powder. When CdTe powder was used as a starting material for the source-layer, the electrical resistivity of the CdTe film deposited in O-2 was about one-tenth lower than that of the film deposited in He. AES, EDS and PIXE analysis showed that the Cd content in the CdTe films deposited in O-2 was Smaller than that in the CdTe films deposited in He. Especially, no oxygen element was detected in the CdTe films deposited in O-2. It turned out that the Sublimated Cd(g) and CdTe(g) from the source-layer formed cadmium oxides in O-2 and as a result the overall composition of vapor source became more Cd-deficient. The CdTe film with less Cd content increased cadmium vacancy defects (V2-Cl+ and ed V-Cd(2-)) and hole concentrations. As the Cd/Te ratio in the starting (Cd+Te) powder decreased, the ed resistivity of the CdTe films decreased and reached at a constant value of about 3x10(4) Omega . cm, regardless of deposition atmosphere. In addition, the resistivity decrease by O-2 treatment was diminished when the Cd/Te ratio was below 0.7, where the composition of CdTe film might be limited by solid solubility (Cd0.92Te1.0) The above results indicated that the resistivity decrease of CdTe films deposited in O-2 was not due to the effect of previously-known oxygen doping but due to the effect of Cd/Te compositional change. (C) 1995 American Institute of Physics
Electrical properties of CuInSe2-films prepared by evaporation of Cu2Se and In2Se3 compounds
No full textWe prepared CuInSe2 films by evaporating In2Se3 and Cu2Se compounds instead of elemental sources, The resulting CuInSe2 film grown at 680 degrees C had a smooth and dense microstructure with the grain size of 2 similar to 3 mu m. But the CuInSe2 films were Cu-rich, with a low resistivity of about 0.1 Omega cm. So we conducted H-2 post annealing to control the electrical resistivity and composition of CuInSe2 films. In a H-2 atmosphere, the resistivity increased to about 100 Omega cm by annealing at 350 degrees C for 1 h. The resistivity decreased again when the annealing temperature was above 350 degrees C, This resistivity change might be related to the contents of Cu, In, Se atoms and the valency states of Cu and In ions in the films. We discussed the reason of resistivity change caused by H-2 post annealing in this paper
SC author and illustrator Kate Salley Palmer signing book
No full textPhotograph of SC author and illustrator Kate Salley Palmer signing boo
Book signing by SC author and illustrator Kate Salley Palmer
No full textPhotograph of Book signing by SC author and illustrator Kate Salley Palme
High-resolution clean-sc
No full textIn this paper a high-resolution extension of CLEAN-SC is proposed: HR-CLEAN-SC. Where CLEAN-SC uses peak sources in “dirty maps” to define so-called source components, HR-CLEAN-SC takes advantage of the fact that source components can likewise be derived from points at some distance from the peak, as long as these “source markers” are on the main lobe of the Point Spread Function (PSF). This is very useful when sources are closely spaced together, such that their PSFs interfere. Then, alternative markers can be sought in which the relative influence by PSFs of other source positions is minimised. For those markers the source components better agree with the actual sources, which allows for better estimation of their locations and strengths. This paper outlines the theory needed to understand this approach and discusses applications to 2D and 3D microphone array simulations with closely spaced sources
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