Functionalized graphene nano-sheets(FGN) of 0.01%-0.05%(mass fraction) were added to produce FGN-cement composites in the form of mortars. Flow properties, mechanical properties and microstructure of the cementitious ...Functionalized graphene nano-sheets(FGN) of 0.01%-0.05%(mass fraction) were added to produce FGN-cement composites in the form of mortars. Flow properties, mechanical properties and microstructure of the cementitious material were then investigated. The results indicate that the addition of FGN decreases the fluidity slightly and improves mechanical properties of cement-based composites significantly. The highest strength is obtained with FGN content of 0.02% where the flexural strength and compressive strength at 28 days are 12.917 MPa and 52.42 MPa, respectively. Besides, scanning electron micrographs show that FGN can regulate formation of massive compact cross-linking structures and thermo gravimetric analysis indicates that FGN can accelerate the hydration reaction to increase the function of the composite effectively.展开更多
Aspergillus oryzae 3042 mycelium pellets were immobilized by crosslinking method with reagents of gelatin and formaldehyde. An orthogonal design table was used to determine the optimal immobilization conditions. The L...Aspergillus oryzae 3042 mycelium pellets were immobilized by crosslinking method with reagents of gelatin and formaldehyde. An orthogonal design table was used to determine the optimal immobilization conditions. The L-aminoacylase activity of immobilized mycelium pellets under optimal conditions was assayed. The results show that the L-aminoacylase activity was 1350 U·g^-1 and the activity retention rate was 83%. The properties of the immobilized preparation were studied. Compared with free pellets, the appropriate pH of reaction system changed from 7.0 to 8.0, temperature changed from 52℃ to 63℃, and the ranges of the optimum reaction conditions were all improved. The effect of Co^2＋ on immobilized mycelium pellets was investigated and the favorable concentration was determined. When the immobilized preparation was used for the resolution of D, L-alanine in a packed bed reactor with 10 mm in diameter, 200 mm in height, the operational stability was increased, and the half-life period was 53 d. Thermal stability analysis shows that the immobilized pellets were more stable than the free pellets.展开更多
基金Project(51102035)supported by the National Natural Science Foundation of China
文摘Functionalized graphene nano-sheets(FGN) of 0.01%-0.05%(mass fraction) were added to produce FGN-cement composites in the form of mortars. Flow properties, mechanical properties and microstructure of the cementitious material were then investigated. The results indicate that the addition of FGN decreases the fluidity slightly and improves mechanical properties of cement-based composites significantly. The highest strength is obtained with FGN content of 0.02% where the flexural strength and compressive strength at 28 days are 12.917 MPa and 52.42 MPa, respectively. Besides, scanning electron micrographs show that FGN can regulate formation of massive compact cross-linking structures and thermo gravimetric analysis indicates that FGN can accelerate the hydration reaction to increase the function of the composite effectively.
文摘Aspergillus oryzae 3042 mycelium pellets were immobilized by crosslinking method with reagents of gelatin and formaldehyde. An orthogonal design table was used to determine the optimal immobilization conditions. The L-aminoacylase activity of immobilized mycelium pellets under optimal conditions was assayed. The results show that the L-aminoacylase activity was 1350 U·g^-1 and the activity retention rate was 83%. The properties of the immobilized preparation were studied. Compared with free pellets, the appropriate pH of reaction system changed from 7.0 to 8.0, temperature changed from 52℃ to 63℃, and the ranges of the optimum reaction conditions were all improved. The effect of Co^2＋ on immobilized mycelium pellets was investigated and the favorable concentration was determined. When the immobilized preparation was used for the resolution of D, L-alanine in a packed bed reactor with 10 mm in diameter, 200 mm in height, the operational stability was increased, and the half-life period was 53 d. Thermal stability analysis shows that the immobilized pellets were more stable than the free pellets.
