Urbanization and industrialization have heightened the risk of groundwater contamination in karst regions,threatening the safety of petrifying spring water.Petrifying spring-moss systems serve as critical interfaces f...Urbanization and industrialization have heightened the risk of groundwater contamination in karst regions,threatening the safety of petrifying spring water.Petrifying spring-moss systems serve as critical interfaces for groundwater-surface water interaction,retaining potentially toxic elements(PTEs)and improving water quality in karst ecosystems.However,it remains uncertain whether the niche differentiation among moss species influences their capacity for the retention of PTEs.This study examines the petrifying spring-moss system in Tongren Grand Canyon,Guizhou Province,a typical karst region in southwestern China.Four dominant moss species with distinct ecological niches were selected for this study.Inductively coupled plasma mass spectrometry(ICPMS)was used to quantify PTEs in the petrifying springmoss systems and their associated water flows.Ecological niche analysis was integrated to evaluate the PTEs enrichment efficiencies of different petrifying spring-moss systems.The results identified Fissidens grandifrons Brid.,Hydrogonium majusculum(C.Muell.)Chen,Brachythecium curtum(Lindb.)Limpr.,and Cratoneuron filicinum(Hedw.)Spruc.var.filicinum as representative species of distinct ecological niches.After filtration through the petrifying spring-moss systems,the concentrations of PTEs in the water were significantly reduced(P<0.05).The retention capacities of moss species varied significantly across ecological niches and were ranked as follows:C.filicinum var.filicinum>B.curtum>F.grandifrons>H.majusculum.This study demonstrates that karst petrifying spring-moss systems efficiently intercept PTEs in groundwater and reveals,from a niche theory angle,the link between moss niche differentiation and their retention efficiency,which offers innovative strategies for ecological remediation of PTEs pollution in global karst groundwater systems.展开更多
This paper investigated the static and fatigue behaviors of steel and composite multi-leaf spring using the ANSYS V I 2 software. The dimensions of an existing conventional leaf spring of a light commercial vehicle we...This paper investigated the static and fatigue behaviors of steel and composite multi-leaf spring using the ANSYS V I 2 software. The dimensions of an existing conventional leaf spring of a light commercial vehicle were used. The same dimensions were used to design composite multi-leaf spring for the two materials, E-glass fiber/epoxy and E-glass fiber/vinyl ester, which are of great interest to the transportation industry. Main consideration was given to the effects of material composition and its fiber orientation on the static and fatigue behaviors of leaf spring. The design constraints were bending stresses, deflection and fatigue life. Compared to the steel leaf spring, the designed composite spring has much lower bending stresses and deflections and higher fatigue life cycles.展开更多
1 Introduction Mengla Basin is a sub-basin in southern evaporitebearing Lanping-Simao Basin.There are many salt springs in the basin.In 2012,11 spring samples were collected for analyses of chemistry and boron,hydroge...1 Introduction Mengla Basin is a sub-basin in southern evaporitebearing Lanping-Simao Basin.There are many salt springs in the basin.In 2012,11 spring samples were collected for analyses of chemistry and boron,hydrogen and oxygen展开更多
An eight-node solid-beam element based on absolute nodal coordinate formulation(ANCF)which uses cubic interpolation at the longitudinal direction and linear at the transverse direction is proposed.The element can accu...An eight-node solid-beam element based on absolute nodal coordinate formulation(ANCF)which uses cubic interpolation at the longitudinal direction and linear at the transverse direction is proposed.The element can accurately discretize the geometry represented by the Bézier volume with the same basis function order.The continuity property of the proposed beam element is verified.Advantages of the proposed element can be found in the application of leaf spring modeling.The parabolically varying thickness of the leaf can be accurately described.Components in leaf spring such as the spring eye and the rubber bushing can be assembled efficiently since the proposed element can be connected at any direction.The ANCF reference node is used to represent the rigid components and the revolute joints in the vehicle suspension system.Static I-shaped cross-section cantilever beam and flexible pendulum model are used to test the accuracy and dynamic performance of the proposed solid-beam element.The leaf spring model shows the flexibility of the element in modeling the complex mechanical system and the balance between the accuracy and the efficiency.展开更多
The effects of Ce addition on the quantity, size, distribution of inclusions and the content of oxygen, sulfur and other hazardous residual elements in spring steel used as fastener in high speed railway were investig...The effects of Ce addition on the quantity, size, distribution of inclusions and the content of oxygen, sulfur and other hazardous residual elements in spring steel used as fastener in high speed railway were investigated by metallographic examination, SEM-EDS and composition analysis. The results indicated that the contents of oxygen decreased with the addition of Ce （[Ce]〈0.1%） and the content of sulfur continually decreased with increasing content of Ce （[Ce]〈1.2%）. However, with the further increase of Ce element addition, the content of [O] and T[O] began to increase. The content of Ce corresponding to the lowest [O] and T[O] lied in the range of 0.10%-0.13%and 0.045%-0.065%, respectively. The addition of Ce in spring steel resulted in the formation of rare earth oxides/oxysulfides and decreased the size of inclusions to less than 3μm in globular or spheroid shape. Moreover, the residual harmful elements （As, P, Pb and Sn） were found to exist in the Ce-containing inclusions, which had proved that the Ce addition could capture the residual elements and suppress their precipitation behaviors in the grain boundary.展开更多
The corrosion resistance and evolution of corrosion products in medium-carbon high-strength spring steels were investigated in a neutral salt spray(5 wt% Na Cl solution). A formation model of γ-Fe OOH and a transform...The corrosion resistance and evolution of corrosion products in medium-carbon high-strength spring steels were investigated in a neutral salt spray(5 wt% Na Cl solution). A formation model of γ-Fe OOH and a transformation model describing the conversion of γ-Fe OOH to α-Fe OOH were constructed. The results indicated that, at the initial corrosion stage, the corrosion resistance was gradually improved with the addition of Cr; however, with the addition of alloying element V, the corrosion resistance decreased. These results were attributed mainly to the initial corrosion stage being closely related to the matrix microstructure parameters such as grain-boundary character and dislocation density. After the rust layer was formed at a later corrosion stage, the corrosion resistance was reinforced with the addition of Cr and V because Cr strongly influenced the composition, structure, and morphology of the corrosion products. The results presented herein show that Cr was conducive to the transformation of γ-Fe OOH into α-Fe OOH. Moreover, V and Cr exhibited obvious synergy and were enriched in the inner layer of the corrosion products.展开更多
基金the National Nature Science Foundation of China(No.32360052)the Department of Science and Technology Foundation of Guizhou Province,China[No.2017(5742)]。
文摘Urbanization and industrialization have heightened the risk of groundwater contamination in karst regions,threatening the safety of petrifying spring water.Petrifying spring-moss systems serve as critical interfaces for groundwater-surface water interaction,retaining potentially toxic elements(PTEs)and improving water quality in karst ecosystems.However,it remains uncertain whether the niche differentiation among moss species influences their capacity for the retention of PTEs.This study examines the petrifying spring-moss system in Tongren Grand Canyon,Guizhou Province,a typical karst region in southwestern China.Four dominant moss species with distinct ecological niches were selected for this study.Inductively coupled plasma mass spectrometry(ICPMS)was used to quantify PTEs in the petrifying springmoss systems and their associated water flows.Ecological niche analysis was integrated to evaluate the PTEs enrichment efficiencies of different petrifying spring-moss systems.The results identified Fissidens grandifrons Brid.,Hydrogonium majusculum(C.Muell.)Chen,Brachythecium curtum(Lindb.)Limpr.,and Cratoneuron filicinum(Hedw.)Spruc.var.filicinum as representative species of distinct ecological niches.After filtration through the petrifying spring-moss systems,the concentrations of PTEs in the water were significantly reduced(P<0.05).The retention capacities of moss species varied significantly across ecological niches and were ranked as follows:C.filicinum var.filicinum>B.curtum>F.grandifrons>H.majusculum.This study demonstrates that karst petrifying spring-moss systems efficiently intercept PTEs in groundwater and reveals,from a niche theory angle,the link between moss niche differentiation and their retention efficiency,which offers innovative strategies for ecological remediation of PTEs pollution in global karst groundwater systems.
文摘This paper investigated the static and fatigue behaviors of steel and composite multi-leaf spring using the ANSYS V I 2 software. The dimensions of an existing conventional leaf spring of a light commercial vehicle were used. The same dimensions were used to design composite multi-leaf spring for the two materials, E-glass fiber/epoxy and E-glass fiber/vinyl ester, which are of great interest to the transportation industry. Main consideration was given to the effects of material composition and its fiber orientation on the static and fatigue behaviors of leaf spring. The design constraints were bending stresses, deflection and fatigue life. Compared to the steel leaf spring, the designed composite spring has much lower bending stresses and deflections and higher fatigue life cycles.
基金supported by grants from the National Program on Key Basic Research Project of China (973 Program, 2011CB403004)
文摘1 Introduction Mengla Basin is a sub-basin in southern evaporitebearing Lanping-Simao Basin.There are many salt springs in the basin.In 2012,11 spring samples were collected for analyses of chemistry and boron,hydrogen and oxygen
基金supported by the National Natural Science Foundation of China(Grant No.11802072)Key Project of Science and Technology of Hu'nan Province(Grant No.2018GK1040).
文摘An eight-node solid-beam element based on absolute nodal coordinate formulation(ANCF)which uses cubic interpolation at the longitudinal direction and linear at the transverse direction is proposed.The element can accurately discretize the geometry represented by the Bézier volume with the same basis function order.The continuity property of the proposed beam element is verified.Advantages of the proposed element can be found in the application of leaf spring modeling.The parabolically varying thickness of the leaf can be accurately described.Components in leaf spring such as the spring eye and the rubber bushing can be assembled efficiently since the proposed element can be connected at any direction.The ANCF reference node is used to represent the rigid components and the revolute joints in the vehicle suspension system.Static I-shaped cross-section cantilever beam and flexible pendulum model are used to test the accuracy and dynamic performance of the proposed solid-beam element.The leaf spring model shows the flexibility of the element in modeling the complex mechanical system and the balance between the accuracy and the efficiency.
基金supported by National Natural Science Foundation of China(5110401351174022)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(44),Beijing Higher Education Young Elite Teacher Project(0349)
文摘The effects of Ce addition on the quantity, size, distribution of inclusions and the content of oxygen, sulfur and other hazardous residual elements in spring steel used as fastener in high speed railway were investigated by metallographic examination, SEM-EDS and composition analysis. The results indicated that the contents of oxygen decreased with the addition of Ce （[Ce]〈0.1%） and the content of sulfur continually decreased with increasing content of Ce （[Ce]〈1.2%）. However, with the further increase of Ce element addition, the content of [O] and T[O] began to increase. The content of Ce corresponding to the lowest [O] and T[O] lied in the range of 0.10%-0.13%and 0.045%-0.065%, respectively. The addition of Ce in spring steel resulted in the formation of rare earth oxides/oxysulfides and decreased the size of inclusions to less than 3μm in globular or spheroid shape. Moreover, the residual harmful elements （As, P, Pb and Sn） were found to exist in the Ce-containing inclusions, which had proved that the Ce addition could capture the residual elements and suppress their precipitation behaviors in the grain boundary.
基金financially supported by the National Natural Science Foundation of China (No.51474031)
文摘The corrosion resistance and evolution of corrosion products in medium-carbon high-strength spring steels were investigated in a neutral salt spray(5 wt% Na Cl solution). A formation model of γ-Fe OOH and a transformation model describing the conversion of γ-Fe OOH to α-Fe OOH were constructed. The results indicated that, at the initial corrosion stage, the corrosion resistance was gradually improved with the addition of Cr; however, with the addition of alloying element V, the corrosion resistance decreased. These results were attributed mainly to the initial corrosion stage being closely related to the matrix microstructure parameters such as grain-boundary character and dislocation density. After the rust layer was formed at a later corrosion stage, the corrosion resistance was reinforced with the addition of Cr and V because Cr strongly influenced the composition, structure, and morphology of the corrosion products. The results presented herein show that Cr was conducive to the transformation of γ-Fe OOH into α-Fe OOH. Moreover, V and Cr exhibited obvious synergy and were enriched in the inner layer of the corrosion products.
