Structural parameters macrostructure

Table II. Some Commonly Used Structural Parameters for the Macrostructure of a Petroleum-Derived Asphaltene...

Figure 1 summarizes the main differences and objectives between the major preparation strategies. A collection of the major individual reaction steps for the synthesis of unsupported catalysts can be found in Table 1. One fundamental insight from this rather schematic comparison is that differences in the reaction kinetics of the synthesis of a given material will lead to different mesoscopic and macroscopic structures which considerably affect the catalytic performance. It is necessary to control these analytically difficult-to-describc parameters with much the same precision as the atomic arrangement or the local electronic structure. Whereas these latter parameters influence the nature of the active site, it is the mcso/macrostructure which controls the distribution and abundance of active sites on a given material. It is necessary in certain cases to apply the costly method of fusion as there is no other way to... 

The macrostructure of a real dispersed material, including plastic foams, cannot be visualized without recurring to a geometrical model hence, the concepts of the material structure are always conventional, being valid only on the basis of the GSE model used. Nevertheless, such concepts are necessary both for a quantitative description of a macrostructure and for a comparative analysis of the morphological parameters of the different cellular plastics. 

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