We present a theoretical study of interactions of anionic and neutral serine （Ser） on pure or metal-doped graphene surfaces using density functional theory calculations. Interactions of both types of Ser with the pu...We present a theoretical study of interactions of anionic and neutral serine （Ser） on pure or metal-doped graphene surfaces using density functional theory calculations. Interactions of both types of Ser with the pure graphene surface show weak non-covalent interactions due to the formation of-COOH…π, -COO^-…π, and -OH…π interactions. On metal- doped graphene, covalent interactions to the surface dominate, due to the formation of strong metal-O and O-metal-O interactions. Furthermore, the doped Fe, Cr, Mn, A1, or Ti enhances the ability of graphene to attract both types of Ser by a combination of the adsorption energy, the density of states, the Mulliken atomic charges, and differences of electron density. At the same time, the interaction strengths of anionic Ser on various graphene surfaces are stronger than those of neutral Ser. These results provide useful insights for the rational design and development of graphene-based sensors for the two forms of Ser by introducing appropriate doped atoms. Ti and Fe are suggested to be the best choices among all doped atoms for the anionic Ser and neutral Ser, respectively.展开更多
Collapse-type shrinkage is one of highly refractory drying defects inlow-medium density plantation-grown eucalypt wood used as solid wood products. Basic density (BD),microfibril angle (MFA), double fibre cell wall th...Collapse-type shrinkage is one of highly refractory drying defects inlow-medium density plantation-grown eucalypt wood used as solid wood products. Basic density (BD),microfibril angle (MFA), double fibre cell wall thickness (DWT), proportion of ray parenchyma (RP),unit cell wall shrinkage, total shrinkage and residual collapse, which are associated withcollapse-type shrinkage characteristics, were investigated by using simple regression method forthree species of collapse-susceptible Eucalyptus urophyll,, E. grandis and E. urophyllaxE.grandis,planted at Dong-Men Forest Farm in Guangxi autonomous region, China. The results indicated that:unit cell wall shrinkage had a extremely strong positive correlation with BD, moderately strongpositive correlation with DWT, and a weakly or moderately negative correlation with RP and MFA;total shrinkage was positively correlated with BD, DWT and RP and negatively related to MFA, but notable to be predicted ideally by any examined factors alone owing to lower R^2 value (R^2≤0.5712);residual collapse was negatively correlated with BD and DWT, linearly positively correlated withMFA, and had strongly positive linear correlation with RP. It is concluded that BD can be used assingle factor (R^2≥ 0.9412) to predicate unit cell wall shrinkage and RP is the relatively soundindicator for predicting residual collapse展开更多
In order to investigate the coolability of a tight lattice core in BWR （boiling water reactors）, an experiment of CHF （critical heat flux） was conducted using a single heater pin flow channel with and without a wi...In order to investigate the coolability of a tight lattice core in BWR （boiling water reactors）, an experiment of CHF （critical heat flux） was conducted using a single heater pin flow channel with and without a wire spacer with the mass flux ranged from 200 kg/（m2.s） to 600 kg/（m2·s）, the inlet temperature from 50 ℃ to 90 ℃ at the pressure of 0.1 MPa. The results of CHF values were compared between two different types of heater pin with and without the wire spacer. The heat removability of flow channel was improved by the wire spacer in comparison with the heater pin flow channel without the wire spacer. The CHF value was higher in the heater pin channel with the wire spacer than in that without the wire spacer.展开更多
文摘We present a theoretical study of interactions of anionic and neutral serine （Ser） on pure or metal-doped graphene surfaces using density functional theory calculations. Interactions of both types of Ser with the pure graphene surface show weak non-covalent interactions due to the formation of-COOH…π, -COO^-…π, and -OH…π interactions. On metal- doped graphene, covalent interactions to the surface dominate, due to the formation of strong metal-O and O-metal-O interactions. Furthermore, the doped Fe, Cr, Mn, A1, or Ti enhances the ability of graphene to attract both types of Ser by a combination of the adsorption energy, the density of states, the Mulliken atomic charges, and differences of electron density. At the same time, the interaction strengths of anionic Ser on various graphene surfaces are stronger than those of neutral Ser. These results provide useful insights for the rational design and development of graphene-based sensors for the two forms of Ser by introducing appropriate doped atoms. Ti and Fe are suggested to be the best choices among all doped atoms for the anionic Ser and neutral Ser, respectively.
基金This work was supported by both the project ( No. 30170754)from Chinese National Natural Science Fund and the national significant fundamental research 'Ascending Plan' program (No.95- 07) authorized by Ministry of Science and Technology, China. And was partly presented at the 54th Annual Meeting of the Japan Wood Research Society in Hokkaido, Japan and at the 7th Pacific Rim Bio-based Composites Symposium in Nanjing, P. R. China.
文摘Collapse-type shrinkage is one of highly refractory drying defects inlow-medium density plantation-grown eucalypt wood used as solid wood products. Basic density (BD),microfibril angle (MFA), double fibre cell wall thickness (DWT), proportion of ray parenchyma (RP),unit cell wall shrinkage, total shrinkage and residual collapse, which are associated withcollapse-type shrinkage characteristics, were investigated by using simple regression method forthree species of collapse-susceptible Eucalyptus urophyll,, E. grandis and E. urophyllaxE.grandis,planted at Dong-Men Forest Farm in Guangxi autonomous region, China. The results indicated that:unit cell wall shrinkage had a extremely strong positive correlation with BD, moderately strongpositive correlation with DWT, and a weakly or moderately negative correlation with RP and MFA;total shrinkage was positively correlated with BD, DWT and RP and negatively related to MFA, but notable to be predicted ideally by any examined factors alone owing to lower R^2 value (R^2≤0.5712);residual collapse was negatively correlated with BD and DWT, linearly positively correlated withMFA, and had strongly positive linear correlation with RP. It is concluded that BD can be used assingle factor (R^2≥ 0.9412) to predicate unit cell wall shrinkage and RP is the relatively soundindicator for predicting residual collapse
文摘In order to investigate the coolability of a tight lattice core in BWR （boiling water reactors）, an experiment of CHF （critical heat flux） was conducted using a single heater pin flow channel with and without a wire spacer with the mass flux ranged from 200 kg/（m2.s） to 600 kg/（m2·s）, the inlet temperature from 50 ℃ to 90 ℃ at the pressure of 0.1 MPa. The results of CHF values were compared between two different types of heater pin with and without the wire spacer. The heat removability of flow channel was improved by the wire spacer in comparison with the heater pin flow channel without the wire spacer. The CHF value was higher in the heater pin channel with the wire spacer than in that without the wire spacer.
