Although oily wastewater treatment realized by superwetting materials has attracted heightened attention in recent years,how to treat enormous-volume emulsion wastewater is still a tough problem,which is ascribed to t...Although oily wastewater treatment realized by superwetting materials has attracted heightened attention in recent years,how to treat enormous-volume emulsion wastewater is still a tough problem,which is ascribed to the emulsion accumulation.Herein,to address this problem,a material is presented by subtly integrating chemical demulsification and 3D inner-outer asymmetric wettability to a sponge substrate,and thus wettability gradient-driven oil directional transport for achieving unprecedented enormous-volume emulsion wastewater treatment is realized based on a“demulsification-transport”mechanism.The maximum treatment volume realized by the sponge is as large as 3 L(2.08×10^(4) L per cubic meter of the sponge)in one cycle,which is about 100 times of the reported materials.Besides,owing to the large pore size of the sponge,9000 L m^(2)h^(-1)(LMH)separation flux and 99.5%separation efficiency are realized simultaneously,which overcomes the trade-off dilemma.Such a 3D inner-outer asymmetric sponge displaying unprecedented advantage in the treatment volume can promote the development of the oily wastewater treatment field,as well as expand the application prospects of superwetting materials,especially in continuous water treatment.展开更多
The amplitude and frequency modulation of near-wall flow structures by the large-scale motions in outer regions is studied in turbulent channel flows. The proper orthogonal decomposition(POD) method is applied to inve...The amplitude and frequency modulation of near-wall flow structures by the large-scale motions in outer regions is studied in turbulent channel flows. The proper orthogonal decomposition(POD) method is applied to investigate the interactions between the near-wall motions and the large-scale flow modes of the outer regions based on two datasets from direct numerical simulation of turbulent channel flows at Reynolds numbers of 550–10 0 0. The fluctuations in the fields u+, v+, w+ and Reynolds shear stress-(uv)+ are studied to understand the mechanism of amplitude and frequency modulation of the nearwall structures by the outer large-scale motions. The amplitude modulation coefficient of the Reynolds shear stress is larger than that of the velocity components. The frequency modulation effect has an opposite influence in the spanwise direction compared to the streamwise direction. The streamwise characteristic frequency increases with increasing large-scale velocity. However, the spanwise characteristic frequency exhibits a decreasing trend with increasing large-scale velocity in the near-wall region.展开更多
Fluctuating wall shear stress in turbulent channel flows is decomposed into small-scale and large-scale components.The large-scale fluctuating wall shear stress is computed as the footprints of the outer turbulent mot...Fluctuating wall shear stress in turbulent channel flows is decomposed into small-scale and large-scale components.The large-scale fluctuating wall shear stress is computed as the footprints of the outer turbulent motions,and the small-scale one is obtained by subtracting the large-scale one from the total,which fully remove the outer influences.We show that the statistics of the small-scale fluctuating wall shear stress is Reynolds number independent at the friction Reynolds number larger than 1000,while which is Reynolds number dependent or the low-Reynolds-number effect exists at the friction Reynolds number smaller than 1000.Therefore,a critical Reynolds number that defines the emergence of universal small-scale fluctuating wall shear stress is proposed to be 1000.The total and large-scale fluctuating wall shear stress intensities approximately follow logarithmic-linear relationships with Reynolds number,and empirical fitting expressions are given in this work.展开更多
台风尺度表征了台风低层风场特定风速半径大小,是台风灾害影响范围的重要度量.针对超强台风“舒力基”(2021),对其尺度可预报性进行初步探讨.结果表明,模式可以模拟出台风发展初期台风尺度(内核尺度RMW、外围尺度R17)的演变趋势.基于集...台风尺度表征了台风低层风场特定风速半径大小,是台风灾害影响范围的重要度量.针对超强台风“舒力基”(2021),对其尺度可预报性进行初步探讨.结果表明,模式可以模拟出台风发展初期台风尺度(内核尺度RMW、外围尺度R17)的演变趋势.基于集合预报的模拟试验,具体分析了内核尺度RMW、外围尺度R17演变及其误差增长特征.台风预报总体误差主要出现在对流层下层850 h Pa,距离台风中心50~150 km.从初始环境场看,初始相对湿度是影响台风尺度误差增长的重要因子,初始高湿环境有利于台风发展阶段的台风尺度高离散度,从而限制了台风尺度的可预报性.在一定程度上,外围风圈半径的可预报性要高于内核风圈半径.展开更多
叶绿体作为植物及藻类细胞中含有内外双层被膜的细胞器,能够通过光合作用过程将光能转化为化学能。大部分的叶绿体蛋白由细胞核基因编码,其前体蛋白是在细胞质中的80S核糖体上合成的。前体蛋白在转运肽的引导下,通过跨越叶绿体外被膜和...叶绿体作为植物及藻类细胞中含有内外双层被膜的细胞器,能够通过光合作用过程将光能转化为化学能。大部分的叶绿体蛋白由细胞核基因编码,其前体蛋白是在细胞质中的80S核糖体上合成的。前体蛋白在转运肽的引导下,通过跨越叶绿体外被膜和内被膜的路径被传送进入叶绿体内部,进而到达发挥其生物学功能的目的微区。目前已知的前体蛋白转运的一个主要途径是通过叶绿体外被膜转运子(translocon in the outer envelope membrane of chloroplast, TOC)和内被膜转运子(translocon in the inner envelope membrane of chloroplast, TIC),在二者的协同作用下前体蛋白得以跨越双层被膜进入叶绿体。文章回顾了TOC-TIC超复合物的结构生物学研究进展,并深入探讨了各组件的功能特性以及前体蛋白易位至叶绿体内部的潜在途径和调控机制。展开更多
基金The authors are grateful for financial support from the National Natural Science Foundation of China(52173111,21788102).
文摘Although oily wastewater treatment realized by superwetting materials has attracted heightened attention in recent years,how to treat enormous-volume emulsion wastewater is still a tough problem,which is ascribed to the emulsion accumulation.Herein,to address this problem,a material is presented by subtly integrating chemical demulsification and 3D inner-outer asymmetric wettability to a sponge substrate,and thus wettability gradient-driven oil directional transport for achieving unprecedented enormous-volume emulsion wastewater treatment is realized based on a“demulsification-transport”mechanism.The maximum treatment volume realized by the sponge is as large as 3 L(2.08×10^(4) L per cubic meter of the sponge)in one cycle,which is about 100 times of the reported materials.Besides,owing to the large pore size of the sponge,9000 L m^(2)h^(-1)(LMH)separation flux and 99.5%separation efficiency are realized simultaneously,which overcomes the trade-off dilemma.Such a 3D inner-outer asymmetric sponge displaying unprecedented advantage in the treatment volume can promote the development of the oily wastewater treatment field,as well as expand the application prospects of superwetting materials,especially in continuous water treatment.
基金supported by the National Natural Science Foundation of China, Basic Science Center Program for “Multiscale Problems in Nonlinear Mechanics” (Grant No. 11988102)the National Natural Science Foundation of China (Grant Nos. 91852204, 11702302)the National Key R&D Program of China (Grant No. 2020YFA0405700)
文摘The amplitude and frequency modulation of near-wall flow structures by the large-scale motions in outer regions is studied in turbulent channel flows. The proper orthogonal decomposition(POD) method is applied to investigate the interactions between the near-wall motions and the large-scale flow modes of the outer regions based on two datasets from direct numerical simulation of turbulent channel flows at Reynolds numbers of 550–10 0 0. The fluctuations in the fields u+, v+, w+ and Reynolds shear stress-(uv)+ are studied to understand the mechanism of amplitude and frequency modulation of the nearwall structures by the outer large-scale motions. The amplitude modulation coefficient of the Reynolds shear stress is larger than that of the velocity components. The frequency modulation effect has an opposite influence in the spanwise direction compared to the streamwise direction. The streamwise characteristic frequency increases with increasing large-scale velocity. However, the spanwise characteristic frequency exhibits a decreasing trend with increasing large-scale velocity in the near-wall region.
基金supports by grants from the National Natural Science Foundation of China(92052202 and 11972175).
文摘Fluctuating wall shear stress in turbulent channel flows is decomposed into small-scale and large-scale components.The large-scale fluctuating wall shear stress is computed as the footprints of the outer turbulent motions,and the small-scale one is obtained by subtracting the large-scale one from the total,which fully remove the outer influences.We show that the statistics of the small-scale fluctuating wall shear stress is Reynolds number independent at the friction Reynolds number larger than 1000,while which is Reynolds number dependent or the low-Reynolds-number effect exists at the friction Reynolds number smaller than 1000.Therefore,a critical Reynolds number that defines the emergence of universal small-scale fluctuating wall shear stress is proposed to be 1000.The total and large-scale fluctuating wall shear stress intensities approximately follow logarithmic-linear relationships with Reynolds number,and empirical fitting expressions are given in this work.
文摘台风尺度表征了台风低层风场特定风速半径大小,是台风灾害影响范围的重要度量.针对超强台风“舒力基”(2021),对其尺度可预报性进行初步探讨.结果表明,模式可以模拟出台风发展初期台风尺度(内核尺度RMW、外围尺度R17)的演变趋势.基于集合预报的模拟试验,具体分析了内核尺度RMW、外围尺度R17演变及其误差增长特征.台风预报总体误差主要出现在对流层下层850 h Pa,距离台风中心50~150 km.从初始环境场看,初始相对湿度是影响台风尺度误差增长的重要因子,初始高湿环境有利于台风发展阶段的台风尺度高离散度,从而限制了台风尺度的可预报性.在一定程度上,外围风圈半径的可预报性要高于内核风圈半径.
文摘叶绿体作为植物及藻类细胞中含有内外双层被膜的细胞器,能够通过光合作用过程将光能转化为化学能。大部分的叶绿体蛋白由细胞核基因编码,其前体蛋白是在细胞质中的80S核糖体上合成的。前体蛋白在转运肽的引导下,通过跨越叶绿体外被膜和内被膜的路径被传送进入叶绿体内部,进而到达发挥其生物学功能的目的微区。目前已知的前体蛋白转运的一个主要途径是通过叶绿体外被膜转运子(translocon in the outer envelope membrane of chloroplast, TOC)和内被膜转运子(translocon in the inner envelope membrane of chloroplast, TIC),在二者的协同作用下前体蛋白得以跨越双层被膜进入叶绿体。文章回顾了TOC-TIC超复合物的结构生物学研究进展,并深入探讨了各组件的功能特性以及前体蛋白易位至叶绿体内部的潜在途径和调控机制。
