The microstructure and surface state of three kinds of polyacrylonitrile-based carbon fibers （T700, T300 and M40） before and after high temperature treatment were investigated. Also, the pyrocarbon and thermal condu...The microstructure and surface state of three kinds of polyacrylonitrile-based carbon fibers （T700, T300 and M40） before and after high temperature treatment were investigated. Also, the pyrocarbon and thermal conductivity of carbon/carbon composites with different carbon fibers as preform were studied. The results show that M40 carbon fiber has the largest crystallite size and the least d002, T300 follows, and TT00 the third. With the increase of heat treatment temperature, the surface state and crystal size of carbon fibers change correspondingly. M40 carbon fiber exhibits the best graphitization property, followed by T300 and then T700. The different microstructure and surface state of different carbon fibers lead to the different microstructures of pyrocarbon and then result in the different thermal conductivities of carbon/carbon composites. The carbon/carbon composite with M40 as preform has the best microstructure in pyrocarbon and the highest thermal conductivity.展开更多
Hepatic stellate cells（HSCs） are a kind of fat-storing cells, the lipid droplets are rich in the Cytoplasm, in which retinyl ester accounts for 42%, triglyceride occupies 28%, cholesterol （total） occupies 13%, pho...Hepatic stellate cells（HSCs） are a kind of fat-storing cells, the lipid droplets are rich in the Cytoplasm, in which retinyl ester accounts for 42%, triglyceride occupies 28%, cholesterol （total） occupies 13%, phospholipids occupies 4% respectively. Studies have continued that thetransforms of HSC phenotype follows the changing of the cell lipid. After the activation of HSC, with HSC phenotype changing from fat-storing cells into myofibroblast, the lipid droplets decreased or disappeared gradually, which means HSCs are under the differentiating process of removing adipose, meawhile triglyceride, and the main content of lipid droplets, also obviously reduced. It was ever declined that during the process of HSC re-fating, the activated HSC would turn into quiescent state. Therefore this shows HSCs fat metabolism is closely related to the biological activity.展开更多
基金Project(201012200233)supported by the Freedom Explore Program of Central South University,China
文摘The microstructure and surface state of three kinds of polyacrylonitrile-based carbon fibers （T700, T300 and M40） before and after high temperature treatment were investigated. Also, the pyrocarbon and thermal conductivity of carbon/carbon composites with different carbon fibers as preform were studied. The results show that M40 carbon fiber has the largest crystallite size and the least d002, T300 follows, and TT00 the third. With the increase of heat treatment temperature, the surface state and crystal size of carbon fibers change correspondingly. M40 carbon fiber exhibits the best graphitization property, followed by T300 and then T700. The different microstructure and surface state of different carbon fibers lead to the different microstructures of pyrocarbon and then result in the different thermal conductivities of carbon/carbon composites. The carbon/carbon composite with M40 as preform has the best microstructure in pyrocarbon and the highest thermal conductivity.
文摘Hepatic stellate cells（HSCs） are a kind of fat-storing cells, the lipid droplets are rich in the Cytoplasm, in which retinyl ester accounts for 42%, triglyceride occupies 28%, cholesterol （total） occupies 13%, phospholipids occupies 4% respectively. Studies have continued that thetransforms of HSC phenotype follows the changing of the cell lipid. After the activation of HSC, with HSC phenotype changing from fat-storing cells into myofibroblast, the lipid droplets decreased or disappeared gradually, which means HSCs are under the differentiating process of removing adipose, meawhile triglyceride, and the main content of lipid droplets, also obviously reduced. It was ever declined that during the process of HSC re-fating, the activated HSC would turn into quiescent state. Therefore this shows HSCs fat metabolism is closely related to the biological activity.
