Annealing of defects

Outdoor operating temperatures of solar cells are around 60°C. At this temperature significant annealing of defects occurs [606], and the stability is better than at 25°C. Interestingly, seasonal measurements of the performance of solar cells show that the efficiency is higher in summer than in winter [609], which was attributed to annealing of defects [610]. However, it was subsequently reported that these seasonal effects are due to the spectral differences in summer and winter, rather than the increased operating temperature in summer [611,612],... 

Dealumination processes are usually used in conjunction with production of the acid form of zeolite Y for many catalytic apphcations, and zeolites A and X are in most cases no longer used in acid catalytic applications because the high amount of aluminum in their frameworks makes them difficult to stabilize using various dealumination techniques. Successful dealumination and at least partial annealing of defects, resulting from movement of silicon cations to the aluminum vacancies, can be assessed by measurement of the reduction of the unit cell size of the zeolite. This unit cell reduction is a consequence of the relative ionic radii of AF (0.54 A) and Si + (0.40A). 

Spinel notation [93]. It is characterised by a pressed lattice (a=0.816 nm instead of 0.824 nm for LiMn204) and has all manganese ions in 4+ oxidation state. The composition of mechanochemically prepared spinels, probably, can be described by a similar formula (Li,D )-[(Mn""Mn l2.,D,]04 or LiMn204+z- On the increase of calcination temperature, the process of reduction of manganese ions and annealing of defects occur. 

In the special case of side-chain LCPs, it was found that the smectic order extends over about 1000 A [24], This value increases with temperature which was interpreted by the annealing of defects. The correlation length also increases with increasing spacer length which means that the smectic order develops more easily when the coupling between the mesogenic cores and the backbone gets weaker. 

In contrast to DTA and thermogravimetry, diffusion structural analysis makes it possible to investigate processes that are not accompanied by thermal effects or mass changes. DSA permits, to examine consolidation, annealing of defects and sintering of powdered or geleous samples, which would be difficult to examine by means of dilatometry. 

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