A novel strategy was developed to prepare the methacrylic gelatin-dopamine(GelMA-DA)/Ag nanoparticles(NPs)/graphene oxide(GO) composite hydrogels with good biocompatibility,mechanical properties,and antibacterial acti...A novel strategy was developed to prepare the methacrylic gelatin-dopamine(GelMA-DA)/Ag nanoparticles(NPs)/graphene oxide(GO) composite hydrogels with good biocompatibility,mechanical properties,and antibacterial activity.Mussel-inspired DA was utilized to modify the GelMA molecules,which imparts good adhesive performance to the hydrogels.GO,interfacial enhancer,not only improves mechanical properties of the hydrogels,but also provides anchor sites for loading Ag NPs through numerous oxygencontaining functional groups on the surface.The experimental results show that the GelMA/Ag NPs/GO hydrogels have good biocompatibility,and exhibit a swelling rate of 202±16%,the lap shear strength of 147±17 kPa,and compressive modulus of 136±53 kPa,in the case of the Ag NPs/GO content of 2 mg/mL.Antibacterial activity of the hydrogels against both gram-negative and gram-positive bacteria is dependent on the Ag NPs/GO content derived from the release of Ag^(+).Furthermore,the GelMA/Ag NPs/GO hydrogels possess good adhesive ability,which is resistant to highly twisted state when stuck on the surface of pigskin.These results demonstrate promising potential of the GelMA-DA/Ag NPs/GO hydrogels as wound dressings for biomedical applications in clinical and emergent treatment.展开更多
This article investigates the improvement of dynamics stability of the ducted fan unmanned aerial vehicles(UAVs) by optimizing its mechanical-structure parameters. The instability phenomenon of the ducted fan unmanned...This article investigates the improvement of dynamics stability of the ducted fan unmanned aerial vehicles(UAVs) by optimizing its mechanical-structure parameters. The instability phenomenon of the ducted fan unmanned aerial vehicles takes place frequently that easily leads to vibration and even out of control, due to complicated airflow. The dynamics equations mirror its dynamics characteristics, which is primarily influenced by the mechanical-structure parameters of the whole system. Based on this, the optimization of mechanical-structure parameters will improve the dynamics stability of the whole system. Therefore, this paper uses the concept of Lyapunov exponents to build the quantification relationship between system's mechanical-structure parameters and its motion stability to enhance its stability. The simulation experimental results indicate that compared with the direct Lyapunov method, the most important advantage of the proposed method is its constructivity, so it is an effective tool for analysis of the motion stability of other non-linear systems such as robots.展开更多
基金Funded by the National Key Research and Development(R&D) Program of China(No.2018YFB1105702)。
文摘A novel strategy was developed to prepare the methacrylic gelatin-dopamine(GelMA-DA)/Ag nanoparticles(NPs)/graphene oxide(GO) composite hydrogels with good biocompatibility,mechanical properties,and antibacterial activity.Mussel-inspired DA was utilized to modify the GelMA molecules,which imparts good adhesive performance to the hydrogels.GO,interfacial enhancer,not only improves mechanical properties of the hydrogels,but also provides anchor sites for loading Ag NPs through numerous oxygencontaining functional groups on the surface.The experimental results show that the GelMA/Ag NPs/GO hydrogels have good biocompatibility,and exhibit a swelling rate of 202±16%,the lap shear strength of 147±17 kPa,and compressive modulus of 136±53 kPa,in the case of the Ag NPs/GO content of 2 mg/mL.Antibacterial activity of the hydrogels against both gram-negative and gram-positive bacteria is dependent on the Ag NPs/GO content derived from the release of Ag^(+).Furthermore,the GelMA/Ag NPs/GO hydrogels possess good adhesive ability,which is resistant to highly twisted state when stuck on the surface of pigskin.These results demonstrate promising potential of the GelMA-DA/Ag NPs/GO hydrogels as wound dressings for biomedical applications in clinical and emergent treatment.
基金Supported by the National Natural Science Foundation of China(No.51575283)Central Public Welfare Basic Scientific Research Institute Special Funds(No.Y919008)
文摘This article investigates the improvement of dynamics stability of the ducted fan unmanned aerial vehicles(UAVs) by optimizing its mechanical-structure parameters. The instability phenomenon of the ducted fan unmanned aerial vehicles takes place frequently that easily leads to vibration and even out of control, due to complicated airflow. The dynamics equations mirror its dynamics characteristics, which is primarily influenced by the mechanical-structure parameters of the whole system. Based on this, the optimization of mechanical-structure parameters will improve the dynamics stability of the whole system. Therefore, this paper uses the concept of Lyapunov exponents to build the quantification relationship between system's mechanical-structure parameters and its motion stability to enhance its stability. The simulation experimental results indicate that compared with the direct Lyapunov method, the most important advantage of the proposed method is its constructivity, so it is an effective tool for analysis of the motion stability of other non-linear systems such as robots.
