The authors proposed a plausible explanation for the deviation of experimental data for sub-micron polycrystals from the Hall-Fetch relation by introducing the configuration entropy. The present paper extends the prev...The authors proposed a plausible explanation for the deviation of experimental data for sub-micron polycrystals from the Hall-Fetch relation by introducing the configuration entropy. The present paper extends the previous two dimensional analysis to the three-dimensional case. The statistical distribution of dislocation lengths within a spherical grain and the bow-out of dislocations are considered. According to Ashby's model, analyses are pursued for the statistically stored dislocations and geometrically necessary dislocations, respectively. It is confirmed that the configuration entropy model can predict the abnormal Hall-Fetch dependence for grain sizes in the sub-micron range.展开更多
Polymer rheology has a long research tradition and holds an important position in the scientific community.It is supposed to be a valuable subject to the vast polymer industry.This article points out the exciting deve...Polymer rheology has a long research tradition and holds an important position in the scientific community.It is supposed to be a valuable subject to the vast polymer industry.This article points out the exciting developments that are transforming our understanding of the world of polymer rheology.We discuss not only the emerging challenges in the area but also how China might wish to seize the moment,pick up the trend and take advantage of the potential economic benefits to the huge petro-chemical industry of China.展开更多
基金The project supported by the National Natural Science Foundation of China (19891180-01)
文摘The authors proposed a plausible explanation for the deviation of experimental data for sub-micron polycrystals from the Hall-Fetch relation by introducing the configuration entropy. The present paper extends the previous two dimensional analysis to the three-dimensional case. The statistical distribution of dislocation lengths within a spherical grain and the bow-out of dislocations are considered. According to Ashby's model, analyses are pursued for the statistically stored dislocations and geometrically necessary dislocations, respectively. It is confirmed that the configuration entropy model can predict the abnormal Hall-Fetch dependence for grain sizes in the sub-micron range.
基金sponsored by the National Natural Science Foundation of China (Grant No. 20910302023).I thank Dr. Lijia An, the director of CIAC, for arranging and accommodating this short course and appreciate the NNSFC's support to advance the science of polymer rheology in China.This article is actually prompted by the interest from NNSFC to explore the future of polymer rheology.The work is supported, in part, by grants (DMR-0821697 and CMMI-0926522) from the National Science Foundation of the United States
文摘Polymer rheology has a long research tradition and holds an important position in the scientific community.It is supposed to be a valuable subject to the vast polymer industry.This article points out the exciting developments that are transforming our understanding of the world of polymer rheology.We discuss not only the emerging challenges in the area but also how China might wish to seize the moment,pick up the trend and take advantage of the potential economic benefits to the huge petro-chemical industry of China.
