Defects maximum expected

Consequently one would expect the conductivity to be a linear function of doping, which is indeed the case, as shown in Fig. 7.10. The conductivity does not increase monotonically, however, but rather goes through a maximum at higher doping levels, a fact that has been attributed to defect-defect interactions and the breakdown of the dilute approximation. 

The Young s modulus of polycrystalline NiAl with a stoichiometric composition is about 235 GPa at room temperature (Harmouche and Wolfenden, 1987). The elastic moduli are functions of the composition, and the Young s modulus reaches a maximum of slightly more than 235 GPa, not at the stoichiometric composition as is expected, but at about 48 at.% Al which may be related to the difference in the defect character on both sides of stoichiometry. The effect of excess vacancies, which are produced by quenching from high temperatures, on the elastic behavior was studied... 

In view of the above findings it is expected that H-H coupling defects in H-T coupled poly(3-alkylthio-phenes) may also lower the conjugation. This is indeed the case. In regioregular poly(3-alkylthiophene) the maximum of the n—n absorption peak is red shifted as compared to FeClj prepared, non-regioregular poly(3-alkylthiophene) (see Table 4.1). 

Our data now provide a reasonable explanation why there may be no obvious defect in iron metabolism in Wilson s disease. Despite the reduction in Cp, suflScient ferroxidase activity remains to prevent anemia. Remember that less than one-tenth of the normal level of ferroxidase is sufficient to cause a maximum mobilization of iron in both in vivo and in vitro experimental systems (46, 50), Thus, in Wilson s disease the level of serum ferroxidase may never become sufficiently low to be rate-hmiting in iron utilization. It was also mentioned earlier that the ferroxidase activity in Wilson s disease serum was higher than expected from the aryl-diamine oxidase activity. Richard W. Topham in our laboratory has been able to isolate a ferroxidase quite distinct from Cp which appears to remain relatively intact in Wilson s disease serum (27). Another possible explanation was oflFered by Hansen et cd, (52) who proposed citrate as an alternative ferroxidase in low Cp serum. 

We have already encountered the concept of thermodynamic adhesion and its related terms such as the work of adhesion. The term is applied to a defined model system and does not take into consideration conditions before or after the formation of the interface, the presence of random flaws or defects in the system, or the bulk physical properties of the components, all of which are of primary importance in the practical application of the concept of adhesion. It is related to molecular interactions such as van der Waals, dipolar, and electrostatic forces but does not consider mechanical or chemical interactions as defined above. It is therefore not a very useful concept in terms of practical adhesion problems, but it serves as a good theoretical tool and to indicate a maximum force or work that a given interface may be expected to transmit before failure (i.e., separation) occurs. 

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