However, problems such as technique sensitivity, postoperative sensitivity, secondary caries and discoloration,are commonly encountered in clinical practice, affecting the final restorative result.

The export control of sensitive technologies and devices related to nuclear, biological and chemical bombs and missiles is a critical part of nonproliferation policies.

This thesis aims at revealing that the criteria of defining products defects is influenced by quality preference and price preference of consumers、the elasticities of supply and demand、the sensitivity of new technology in a certain industry, which are determined by economic development level、income、technology、product characteristics etc in the opportunity set of a certain country.