http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Molecular dynamics study on mechanical properties of C-S-H composites
Xianfeng Wang,Peng Wei,Rui Han,Wei Xie,Taoran Li,Dawang Li,Yonggang Peng,Zhen Chen,Feng Xing 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.S1
In this paper, the mechanical properties of calcium silicate hydrate gel (C-S-H) are investigated with molecular dynamics (MD)simulations, in which the Tobermorite 9Å, Tobermorite 11Å, Tobermorite 14Å and Jennite crystals are treated as fundamentalmodels of the C-S-H nanostructure. The initial structures of the crystal models are firstly preprocessed and optimized, andthen are simulated in the canonical (NVT) ensemble conditions. The orthotropic elastic constants of the C-S-H nanostructureare determined and used to derive the bulk and shear moduli via the Voigt-Reuss-Hill method. The self-consistent, Mori-Tanaka, and Voigt methods are employed to compute the mechanical properties of various mixtures of C-S-H composites withdifferent porosities. The simulated results are found to be in a reasonable agreement with those obtained from nanoindentationtests, while the result obtained from the Mori-Tanaka method appears to be the closest to the experimental one. It could also be observed that the mechanical properties of C-S-H vary within a certain range as the porosity and proportionsof the components change.
( Sang Gil Lee ),( Taoran Wang ),( Terrence M. Vance ),( Patrice Hurbert ),( Dae-ok Kim ),( Sung I. Koo ),( Ock K. Chun ) 한국미생물 · 생명공학회 2017 Journal of microbiology and biotechnology Vol.27 No.2
Although several analytical methods for measuring total antioxidant capacity (TAC) have been applied to biological samples, there were often dissimilar results due to the different principles of methods applied. Thus, this study aimed to validate four conventional analytical methods for measuring plasma TAC, including the ABTS assay, DPPH assay, FRAP assay, and ORAC assay, by comparing with urinary 8-isoprostane concentration. In addition, TAC results were compared with antioxidant enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase in erythrocyte, and catalase in plasma. Plasma TAC measure by ABTS assay was strongly correlated with the result by FRAP assay. Plasma TAC by FRAP and ORAC assays were negatively correlated with erythrocyte SOD activity. The agreement among the four TAC assay methods and 8-isoprostane was determined using 95% prediction limits of linear regression, expressed as the mean of 8-isoprostane ± 95% prediction limits. The ABTS method better agreed with 8-isoprostane than the other methods, demonstrating narrow prediction of limits. Furthermore, only plasma TAC determined by the ABTS assay was inversely correlated with urinary 8-isoprostane (r = -0.35, p < 0.05). In summary, the ABTS assay would be an appropriate method to measure overall plasma antioxidant capacity and predict the body`s antioxidant status.