The creep behavior of Al2O3.SiO2 fiber reinforced ZL109 composites has been investigated at four temperatures ranging from 553 to 623 K. The results show high stress exponent and high apparent creep activation energy....The creep behavior of Al2O3.SiO2 fiber reinforced ZL109 composites has been investigated at four temperatures ranging from 553 to 623 K. The results show high stress exponent and high apparent creep activation energy. A good correlation between the normalized creep rate and normalized effective stress means that the true stress exponent of minimum creep strain rate of the composite is very close to 5, and the minimum creep strain rate is matrix lattice diffusion controlled. The threshold stress decreases with increasing temperature linearly and disappears at a temperature close to 623 K. It is assumed that the long range internal back stresses generated in creep reduce the load transfer to fibers and the interaction between dislocations and strengthening precipitates decreases at high temperature. At a high temperature where the long range internal back stresses is very close to the applied stress, the threshold stress disappears.展开更多
Summary What is already known about this topic?Previous surveys have mainly focused on how well residents and primary school students have understood the core knowledge of echinococcosis control and are limited in ter...Summary What is already known about this topic?Previous surveys have mainly focused on how well residents and primary school students have understood the core knowledge of echinococcosis control and are limited in terms of the comprehensiveness of the knowledge category and respondents.What is added by this report?There were some shortcomings in related knowledge of echinococcosis among students,which showed a tendency to know methods but not the rationale.The differences among regions indicated a lack of a unified system for training educators and allocating comprehensive educational material.What are the implications for public health practices?The results of this study provide evidence to potentially help improve health education programs in the new phase of echinococcosis prevention and control in China.展开更多
文摘The creep behavior of Al2O3.SiO2 fiber reinforced ZL109 composites has been investigated at four temperatures ranging from 553 to 623 K. The results show high stress exponent and high apparent creep activation energy. A good correlation between the normalized creep rate and normalized effective stress means that the true stress exponent of minimum creep strain rate of the composite is very close to 5, and the minimum creep strain rate is matrix lattice diffusion controlled. The threshold stress decreases with increasing temperature linearly and disappears at a temperature close to 623 K. It is assumed that the long range internal back stresses generated in creep reduce the load transfer to fibers and the interaction between dislocations and strengthening precipitates decreases at high temperature. At a high temperature where the long range internal back stresses is very close to the applied stress, the threshold stress disappears.
基金Supported by the Research Projects of Shanghai Municipal Health Commission(Grant No.2021Y0213).
文摘Summary What is already known about this topic?Previous surveys have mainly focused on how well residents and primary school students have understood the core knowledge of echinococcosis control and are limited in terms of the comprehensiveness of the knowledge category and respondents.What is added by this report?There were some shortcomings in related knowledge of echinococcosis among students,which showed a tendency to know methods but not the rationale.The differences among regions indicated a lack of a unified system for training educators and allocating comprehensive educational material.What are the implications for public health practices?The results of this study provide evidence to potentially help improve health education programs in the new phase of echinococcosis prevention and control in China.
