Conversion efficiency, improved

The optimized power conversion efficiency improved from 9.4 + 0.76 to 10.2 + 0.58% after the addition of 0.5% by volume of ethylammonium iodide. These devices exhibit an extremely high stability. 

Twice-daily sc injection of 10 or 20 p.g human GRF (hGRF)(l-44)NH2/kg BW for 36 days in barrows weighing 78 kg improved feed conversion efficiency and lean content of the ham (102). However, treatment with hGRF was less effective than pST injection of 20 or 40 Fg/kg BW at the same frequency (103). 

The addition of potassium carbonate or chloride to the fusion mix reduces the loss of volatile siUcon tetrafluoride, improving the conversion efficiency. 

Designing tandem cells is complex. For example, each cell must transmit efficiently the insufficiently energetic photons so that the contacts on the backs of the upper cells are transparent to these photons and therefore caimot be made of the usual bulk metal layers. Unless the cells in a stack can be fabricated monolithically, ie, together on the same substrate, different external load circuits must be provided for each cell. The thicknesses and band gaps of individual cells in the stack must be adjusted so that the photocurrents in all cells are equal. Such an optimal adjustment is especially difficult because the power in different parts of the solar spectmm varies under ambient conditions. Despite these difficulties, there is potential for improvement in cell conversion efficiency from tandem cells. 

Lasers act as sources and sometimes as amplifiers of coherent k—uv radiation. Excitation in lasers is provided by external particle or photon pump sources. The high energy densities requked to create inverted populations often involve plasma formation. Certain plasmas, eg, cadmium, are produced by small electric discharges, which act as laser sources and amplifiers (77). Efforts that were dkected to the improvement of the energy conversion efficiencies at longer wavelengths and the demonstration of an x-ray laser in plasma media were successful (78). 

Besides improving stability, a practical goal of surface modification has been to utilize redox reactions, otherwise not applicable, to yield better electrical characteristics such as higher open-circuit photovoltage, and to promote high conversion efficiencies. 

By using a multichamber system [129], exchange of residual gases between successive depositions will be strongly decreased, and very sharp interfaces can be made. Furthermore, the use of a load-lock system ensures high quality of the background vacuum, and thus low levels of contaminants in the bulk layers. Multichamber reactor systems have been used for the fabrication of solar cells, and considerable improvements in energy conversion efficiency have been achieved [130, 131]. 

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