Changes during irradiation

Manufacturers provide operating characteristics of photovoltaic modules in standard conditions, which are defined by a solar irradiance value equal to 1000 W/m2 and a photovoltaic module temperature equal to 25°C. The most important of them is the maximum power that can be obtained at these conditions and is used for the determination of the photovoltaic module nominal power. However, in a considered site, solar irradiance changes during the day. In addition, depending on the environmental conditions, due to the internal thermal losses of the photovoltaic module, its temperature also varies. As a result, the maximum extracted power is usually lower than that provided by the manufacturers. 

The data also showed evidence that the nature of the BC site changed during warming from 30 K to 550 K. There was no loss of 2H from the sample on warming to 550 K, consistent with other data quoted already (Umezawa et al., 1988b). Of particular interest is a shift in the 2H position, accompanied by a redistribution over different sites, which occurred at 140 K. In interpreting this data, Bech Nielsen assumed that the 2H atom sites were determined by interaction with irradiation-induced defects. In-... 

Figure 2. Electronic absorption spectral changes during 366-nm irradiation of an isooctane solution of [ReH5(PMe2Ph)s] under an Ht atmosphere.

Figure 4. UV-visible spectral changes during 366-nm photolysis of a CHSCN solution of [PtgHs-(dppm)i PF6. Arrows indicate the direction of the spectral changes after beginning photolysis and the spectra were successively recorded after 0, 0.5, 1, 1.5, 2, 3, and 5 min total irradiation time.

In 2-propanol solutions, acidified with hydrogen chloride, 7 is photoreduced quantitatively to 4-hydroxylaminopyridine 3) as determined by following the spectral changes during irradiation and workup under alkaline or neutral conditions to yield 4,4 -azo- or 4,4 -azoxypyridine 77). 

We can learn the structural change in the crystals during topochemical polymerization by powder X-ray diffraction measurements. X-ray diffraction profiles continuously changed during the polymerization of 1 under the irradiation of an X-ray beam (Fig. 5) [51]. The reflections shifted and approached the reflection position of the polymer. This suggests that the polymerization... 

Table 1 summarizes the changes, during the irradiation times, of the products quantities and the chemical yields. In general, benzaldehyde, benzyl alcohol and benzoic acid were detected as the main products. During experiments 1 and 5, ben zyl alcohol was detected as traces only also in experiment 3, benzoic acid was detected as traces, and that only after prolonged irradiation times. It is inte resting to mention here, that, in all experiments, traces of 2-, 3-, and 4- ere sols were also detected. In addition, under the experimental conditions 2, tra ces of benzyl benzoate ( 2 ) and o-benzyl benzoic acid ( 3 ) were detected. 

Changes in the natural microflora of sea foods as a result of irradiation and during subsequent storage at low temperature. 

A further complication is the basic assumption of the statistical methods that source profiles neither change during air transport nor with time. Therefore they cannot be applied strictly to secondary aerosol constituents formed in the atmosphere by gas-to-particle conversion processes. Still, the secondary aerosol constituents tend to be grouped into one source group since they have a common source , i.e. formation in air triggered by solar irradiation. 

The spectral change during this progressive warming to room temperature is shown in Fig. 12 for the sample irradiated and photobleached at 77 K. Elimination of the anion radical by photobleaching with visible light makes the analysis of the spectral shape easy. Then the observed spectral change indicates ... 

The stereochemical course is not striking as in the former case observing, on appropriate cycloalkanes, a mixture of isomeric 1,2-dioxolanes. The ratio does not change during the irradiation [109]. In this case, to account for the catalysis of BP, Schaap et al. suggested a higher cage escape efficiency of the radical cation (BP+) from the radical ion pair, compared with that of the radical cation (74a+). Thus, the secondary exothermic electron transfer between 74a and (BP+) (exothermic by ca. 0.5 eV) is expected to occur at diffusion-controlled rate. 

Fig. 16 Structural changes during irradiation. Below the gelation dose Dg, an increasing of the molecular weight occurs. Mw becomes infinite at Dg. Above Dg, the formation of macroscopic networks starts (gel content >0)...

Fig. 1. Spectral changes during the photolysis of 2.37 x 10 " M osmocene in 5 M H2SO4 under argon at room temperature after 0 min (a), 20, 40, and 80 min (b) irradiation times with Airr=254 nm 1-cm cell.

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