In recent years, nanozymes have received more and more attention, but the low activity limits the development of nanozymes. Therefore, the design and development of efficient nanozymes is still a major challenge for r...In recent years, nanozymes have received more and more attention, but the low activity limits the development of nanozymes. Therefore, the design and development of efficient nanozymes is still a major challenge for researchers. Herein, the Fe,N co-doped ultrathin hollow carbon framework(Fe,N-UHCF) exhibit ultra-high peroxidase-like activity. The specific activity of Fe,N-UHCF nanozyme is as high as 36.6 U/mg,which is much higher than almost all of other reported nanozymes. In practical applications, the Fe,N-UHCF show good antibacterial effects.展开更多
Uncertainty impact of random geometric variations on the aerodynamic performance of low-pressure turbine blades is considerable,which is further amplified by the current ultra-high-lift design trend for weight reducti...Uncertainty impact of random geometric variations on the aerodynamic performance of low-pressure turbine blades is considerable,which is further amplified by the current ultra-high-lift design trend for weight reduction.Therefore,this uncertainty impact on ultra-highly loaded blades under extreme operational conditions near the margins with potential large-scale open separation is focused on in this study.It is demonstrated that this impact is significant,unfavourable,and nonlinear,which is clearly severer under extreme conditions.In addition to the overall attenuation and notable scattering of specific performance,the operational margins with open separation are also notably scattered with great risk of significant reduction.This scattering and nonlinearity are dominated by the variations in leading-edge thickness.The thinning of leading edge triggers local transition,enhancing downstream friction and reducing resistance to open separation,which is further exacerbated by operational deterioration.However,the opposite thickening yields less benefit,implying nonlinearity.This unfavourable impact highlights the need for robust aerodynamic design,where both a safer operational condition and a more robust blade are indispensable,i.e.,a compromise among performance,weight,and robustness.Besides the necessary limitation of loading levels,a mid-loaded design is recommended to reduce adverse pressure gradients in both the leading edge and rear region of the suction side,which helps to decrease the susceptibility of the transition and open separation to random perturbations.Similar improvements can also be achieved by appropriately thickening the leading edge.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21671149,21571140,21531005 and 21703156)the 973 Program(No.2014CB845601)+3 种基金the Program for Innovative Research Team in University of Tianjin(No.TD13–5074)the Natural Science Foundation of Tianjin(No.18JCQNJC76000)the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(No.2021KJ190)the Jiangsu Provincial Double-Innovation Doctor Program(No.02300053)。
文摘In recent years, nanozymes have received more and more attention, but the low activity limits the development of nanozymes. Therefore, the design and development of efficient nanozymes is still a major challenge for researchers. Herein, the Fe,N co-doped ultrathin hollow carbon framework(Fe,N-UHCF) exhibit ultra-high peroxidase-like activity. The specific activity of Fe,N-UHCF nanozyme is as high as 36.6 U/mg,which is much higher than almost all of other reported nanozymes. In practical applications, the Fe,N-UHCF show good antibacterial effects.
基金This study was supported by the National Science and Technology Major Project,China(No.J2019-II-0012-0032),which is gratefully acknowledged.
文摘Uncertainty impact of random geometric variations on the aerodynamic performance of low-pressure turbine blades is considerable,which is further amplified by the current ultra-high-lift design trend for weight reduction.Therefore,this uncertainty impact on ultra-highly loaded blades under extreme operational conditions near the margins with potential large-scale open separation is focused on in this study.It is demonstrated that this impact is significant,unfavourable,and nonlinear,which is clearly severer under extreme conditions.In addition to the overall attenuation and notable scattering of specific performance,the operational margins with open separation are also notably scattered with great risk of significant reduction.This scattering and nonlinearity are dominated by the variations in leading-edge thickness.The thinning of leading edge triggers local transition,enhancing downstream friction and reducing resistance to open separation,which is further exacerbated by operational deterioration.However,the opposite thickening yields less benefit,implying nonlinearity.This unfavourable impact highlights the need for robust aerodynamic design,where both a safer operational condition and a more robust blade are indispensable,i.e.,a compromise among performance,weight,and robustness.Besides the necessary limitation of loading levels,a mid-loaded design is recommended to reduce adverse pressure gradients in both the leading edge and rear region of the suction side,which helps to decrease the susceptibility of the transition and open separation to random perturbations.Similar improvements can also be achieved by appropriately thickening the leading edge.
