Threshold appearance time

Threshold appearance times and maximum translational energies of Cl photofragments from CI2 solid photodissociation. 

Catalyst deactivation (e.g. deposition of coke as a function of time) changes the porous structure with time. At a certain time the pore network cannot be passed by the reactant gas. This is the so-called percolation threshold [52]. Before this percolation threshold appears pore clusters of different size may be found within the network and at least one cluster ranges over the entire pellet. Percolation theory deals with the number and properties of these clusters. 

Experimental dependences of conductivity cr of the CPCM on conducting filler concentration have, as a rule, the form predicted by the percolation theory (Fig. 2, [24]). With small values of C, a of the composite is close to the conductivity of a pure polymer. In the threshold concentration region when a macroscopic conducting chain appears for the first time, the conductivity of a composite material (CM) drastically rises (resistivity Qv drops sharply) and then slowly increases practically according to the linear law due to an increase in the number of conducting chains. 

The probability of making a correct decision to clean is l-a(x), and has been mapped on Figure 3b Most of the time it appears that this probability is less than 50 percent except in the central zone next to the pollution source. Besides changing the threshold value 500, one way to improve this probability is to take more samples (increase the number of data N) which would decrease the variance and skewness of the conditional pdf fx(z (N)). 

As a rule, short nucleation times are the prerequisite for monodisperse particle formation. A recent mechanistic study showed that when Pt(acac)2 is reduced by alkylalu-minium, virtually all the Pt cluster nuclei appear at the same time and have the same size [86]. The nucleation process quickly consumes enough of the metal atoms formed initially to decrease their concentration below the critical threshold. No new metal cluster nuclei are created in the subsequent diffusion-controlled growth stage. 

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