Abstract： A joint solution model of variabk：-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated...Abstract： A joint solution model of variabk：-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated by the finite element method （FEM）. The results are basically consistent with relative experimental data. The calculated average heat transfer coefficient reaches 1.7~105 W/（m2. K）. When the equal percentage valve is used, the system needs the minimum requirements of valve control, but brings the highest construction cost. With the： decrease of initial steam pressure, the heat transfer intensity also weakens but the steam flow increases. With the initial water filling coefficient increasing or the temperature of steam supply decreasing, the amount of accumulative steam flow increases with the growth of steam pressure. When the pressure of steam supply drops, the steam flow gradient increases during the maximum opening period of control valve, and causes the maximum steam flow to increase.展开更多
The resistance loss of transportation was studied and the influences of buoyancy layout,mineral content and elastic modulus of flexible hose were investigated based on three-dimensional finite element model of fluid-s...The resistance loss of transportation was studied and the influences of buoyancy layout,mineral content and elastic modulus of flexible hose were investigated based on three-dimensional finite element model of fluid-solid interaction by MSC.MARC/MENTAT software.The numerical results show that the resistance losses increase with the increase of mineral content Cv and velocity of internal fluid v and decrease with the increase of elastic modulus E of flexible hose.The buoyancy layout and the velocity of internal fluid have greater impacts on the resistance losses than the elastic modulus of flexible hose.In order to reduce the resistance losses and improve the efficiency of the deep-ocean mining,Cv and v must be restricted in a suitable range (e.g.10%-25% and 2.5-4 m/s).Effective buoyancy layout (such as Scheme C and D) should be adopted and the suitable material of moderate E should be used for the flexible hose in deep-ocean mining.展开更多
To predict three-dimensional temperature distribution of molten aluminum and its influencing factors inside an industrial aluminum holding furnace,a fluid-solid coupled method was presented.The fluid-solid coupled mat...To predict three-dimensional temperature distribution of molten aluminum and its influencing factors inside an industrial aluminum holding furnace,a fluid-solid coupled method was presented.The fluid-solid coupled mathematics models of aluminum holding furnace in the premixed combustion processing were established based on mass conservation,moment conservation,momentum conservation,energy conservation and chemistry species conservation.Computational results agree well with the test data of the typical condition.The maximum combustion temperature is 1 850 K.The average temperature of the molten aluminum is 1 158 K,and the maximum temperature difference is about 240 K.The average temperature increases 0.3 ℃ while the temperature of combustion air increases 1 ℃.The optimal excess air ratio is 1.25-1.30.展开更多
Permeability is a vital property of rock mass, which is highly affected by tectonic stress and human engineering activities. A comprehensive monitoring of pore pressure and flow rate distributions inside the rock mass...Permeability is a vital property of rock mass, which is highly affected by tectonic stress and human engineering activities. A comprehensive monitoring of pore pressure and flow rate distributions inside the rock mass is very important to elucidate the permeability evolution mechanisms, which is difficult to realize in laboratory, but easy to be achieved in numerical simulations. Therefore, the particle flow code （PFC）, a discrete element method, is used to simulate permeability behaviors of rock materials in this study. Owe to the limitation of the existed solid-fluid coupling algorithm in PFC, an improved flow-coupling algorithm is presented to better reflect the preferential flow in rock fractures. The comparative analysis is conducted between original and improved algorithm when simulating rock permeability evolution during triaxial compression, showing that the improved algorithm can better describe the experimental phenomenon. Furthermore, the evolution of pore pressure and flow rate distribution during the flow process are analyzed by using the improved algorithm. It is concluded that during the steady flow process in the fractured specimen, the pore pressure and flow rate both prefer transmitting through the fractures rather than rock matrix. Based on the results, fractures are divided into the following three types： I） fractures link to both the inlet and outlet, II） fractures only link to the inlet, and III） fractures only link to the outlet. The type I fracture is always the preferential propagating path for both the pore pressure and flow rate. For type II fractures, the pore pressure increases and then becomes steady. However, the flow rate increases first and begins to decrease after the flow reaches the stop end of the fracture and finally vanishes. There is no obvious pore pressure or flow rate concentration within type III fractures.展开更多
According to the characteristics of thin-layer rolling and pouting construction technology and the complicated mechanical behavior of the roller compacted concrete dam （RCCD） construction interface, a constitutive m...According to the characteristics of thin-layer rolling and pouting construction technology and the complicated mechanical behavior of the roller compacted concrete dam （RCCD） construction interface, a constitutive model of endochronic damage was established based on the endochronic theory and damage mechanics. The proposed model abandons the traditional concept of elastic-plastic yield surface and can better reflect the real behavior of rolled control concrete. Basic equations were proposed for the fluid-solid coupling analysis, and the relationships among the corresponding key physical parameters were also put forward. One three-dimensional finite element method （FEM） program was obtained by studying the FEM type of the seepage-stress coupling intersection of the RCCD. The method was applied to an actual project, and the results show that the fluid-solid interaction influences dam deformation and dam abutment stability, which is in accordance with practice. Therefore, this model provides a new method for revealing the mechanical behavior of RCCD under the coupling field.展开更多
CD40 receptor and its ligand CD40 L are the members of TNFR and TNF family,respectively.CD40 is expressed on antigen-presenting cells(APC)as a monomer,and would be dimerized upon its oligomerization through binding to...CD40 receptor and its ligand CD40 L are the members of TNFR and TNF family,respectively.CD40 is expressed on antigen-presenting cells(APC)as a monomer,and would be dimerized upon its oligomerization through binding to its ligand CD40 L.Such dimer formation was shown to be essential for some CD40 signaling events,including phosphoinositide-3 kinase(PI-3 K)activation,the subsequent B7-2 upregulation and the production of IL-8.CD40 L is primarily expressed on activated T cells and activated platelets,and acts as an important costimulatory molecule especially on T follicular helper cells.It is believed that CD40-CD40 L interaction deeply involved in many immune events for the host defense against pathogens and cancer.CD40-CD40 L interaction mediates intracellular signaling along different pathways,such as the canonical and noncanonical nuclear factorκB pathway,mitogen-activated protein kinases,phosphatidylinositol-3 kinase(PI3K)and the phospholipase Cy pathway,is necessary for successful adaptive immune responses mainly relevant to development of CD8+CTLs,and is deeply involved in cross-talks among T cell,B cell,tumor cell,platelet and etc.However,interaction of CD40 with platelet CD40 L would occur in hemodynamics environments,and the regulation of force on this interaction remain unclear.Besides polymerization of CD40,the hemodynamic environment could be believed to regulate interaction between CD40 and its ligand.To reveal the mechanical regulation mechanism of interaction between CD40 L and CD40,atomic force microscope(AFM)was used in the adhesion frequency assay for measuring two-dimensional(2D)kinetics of CD40 L with CD40(the monomer and its dimer)at zero-force and force-clamp assay for measuring single-bond lifetimes of CD40 L/CD40 complex in a range of forces at single-molecule level.AFM cantilever probes were functionalized by incubation with CD40 L in buffer,and soaked in phosphate-buffered saline(PBS)containing 1%bovine serum albumin(BSA)to block nonspecific binding.Polystyrene dishes were coated with CD40(the monomer and its dimer)and then filled with PBS containing 1%BSA.Our data showed that the adhesion frequency of CD40 L with CD40 monomer and its dimer was 0.10 and0. 15,respectively,showing a higher affinity of CD40 L to CD40 dimer rather than its monomer;the rupture force for CD40 L dissociating from CD40 monomer and its dimer was 23 and 31pN,respectively,demonstrating a higher mechanical strength of complex of CD40 L with CD40 dimer instead of monomer;and increasing tension will prolong first and then shorten the bond lifetime of CD40 L-CD40 complex with force threshold of about 1OpN,and dimerization of CD40 had significantly increased enhanced the bond lifetime of CD40 L-CD40 complex,showing a dimerization-enhanced affinity of CD40 to CD40 L and'Catch-Slip'bond mechanism of CD40 L-CD40 interaction.These results suggest that,through upregulating the binding affinity with CD40 L,the polymerization of CD40 stabilizes the linkers and thereby communication between cell and cell,so does the force being small than the force threshold Both CD40 polymerization-and'Catch bond'-induced enhancement of affinity of CD40 with CD40 L may be necessary for stable cross talks between two cells.This finding may be useful for understanding CD40/CD40 L-induced events importantly in physiological or pathological processes at molecular and cellular level.展开更多
基金Project(20080431380) supported by China Postdoctoral Science Foundation
文摘Abstract： A joint solution model of variabk：-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated by the finite element method （FEM）. The results are basically consistent with relative experimental data. The calculated average heat transfer coefficient reaches 1.7~105 W/（m2. K）. When the equal percentage valve is used, the system needs the minimum requirements of valve control, but brings the highest construction cost. With the： decrease of initial steam pressure, the heat transfer intensity also weakens but the steam flow increases. With the initial water filling coefficient increasing or the temperature of steam supply decreasing, the amount of accumulative steam flow increases with the growth of steam pressure. When the pressure of steam supply drops, the steam flow gradient increases during the maximum opening period of control valve, and causes the maximum steam flow to increase.
基金Project(2006AA09Z240)supported by the National High Technology Research and Development Program of China
文摘The resistance loss of transportation was studied and the influences of buoyancy layout,mineral content and elastic modulus of flexible hose were investigated based on three-dimensional finite element model of fluid-solid interaction by MSC.MARC/MENTAT software.The numerical results show that the resistance losses increase with the increase of mineral content Cv and velocity of internal fluid v and decrease with the increase of elastic modulus E of flexible hose.The buoyancy layout and the velocity of internal fluid have greater impacts on the resistance losses than the elastic modulus of flexible hose.In order to reduce the resistance losses and improve the efficiency of the deep-ocean mining,Cv and v must be restricted in a suitable range (e.g.10%-25% and 2.5-4 m/s).Effective buoyancy layout (such as Scheme C and D) should be adopted and the suitable material of moderate E should be used for the flexible hose in deep-ocean mining.
基金Project(2006AA03Z523) supported by the National High-Tech Research and Development Program of ChinaProject(08C26224302178) supported by the Innovation Foundation of Central South University,China
文摘To predict three-dimensional temperature distribution of molten aluminum and its influencing factors inside an industrial aluminum holding furnace,a fluid-solid coupled method was presented.The fluid-solid coupled mathematics models of aluminum holding furnace in the premixed combustion processing were established based on mass conservation,moment conservation,momentum conservation,energy conservation and chemistry species conservation.Computational results agree well with the test data of the typical condition.The maximum combustion temperature is 1 850 K.The average temperature of the molten aluminum is 1 158 K,and the maximum temperature difference is about 240 K.The average temperature increases 0.3 ℃ while the temperature of combustion air increases 1 ℃.The optimal excess air ratio is 1.25-1.30.
基金Project（BK20150005） supported by the Natural Science Foundation of Jiangsu Province for Distinguished Young Scholars, China Project（2015XKZD05） supported by the Fundamental Research Funds for the Central Universities, China
文摘Permeability is a vital property of rock mass, which is highly affected by tectonic stress and human engineering activities. A comprehensive monitoring of pore pressure and flow rate distributions inside the rock mass is very important to elucidate the permeability evolution mechanisms, which is difficult to realize in laboratory, but easy to be achieved in numerical simulations. Therefore, the particle flow code （PFC）, a discrete element method, is used to simulate permeability behaviors of rock materials in this study. Owe to the limitation of the existed solid-fluid coupling algorithm in PFC, an improved flow-coupling algorithm is presented to better reflect the preferential flow in rock fractures. The comparative analysis is conducted between original and improved algorithm when simulating rock permeability evolution during triaxial compression, showing that the improved algorithm can better describe the experimental phenomenon. Furthermore, the evolution of pore pressure and flow rate distribution during the flow process are analyzed by using the improved algorithm. It is concluded that during the steady flow process in the fractured specimen, the pore pressure and flow rate both prefer transmitting through the fractures rather than rock matrix. Based on the results, fractures are divided into the following three types： I） fractures link to both the inlet and outlet, II） fractures only link to the inlet, and III） fractures only link to the outlet. The type I fracture is always the preferential propagating path for both the pore pressure and flow rate. For type II fractures, the pore pressure increases and then becomes steady. However, the flow rate increases first and begins to decrease after the flow reaches the stop end of the fracture and finally vanishes. There is no obvious pore pressure or flow rate concentration within type III fractures.
基金Projects(51139001,51179066,51079046,50909041) supported by the National Natural Science Foundation of ChinaProject(NCET-10-0359) supported by the Program for New Century Excellent Talents in UniversityProjects(2009586012,2009586912,2010585212)supported by the Special Fund of State Key Laboratory of China
文摘According to the characteristics of thin-layer rolling and pouting construction technology and the complicated mechanical behavior of the roller compacted concrete dam （RCCD） construction interface, a constitutive model of endochronic damage was established based on the endochronic theory and damage mechanics. The proposed model abandons the traditional concept of elastic-plastic yield surface and can better reflect the real behavior of rolled control concrete. Basic equations were proposed for the fluid-solid coupling analysis, and the relationships among the corresponding key physical parameters were also put forward. One three-dimensional finite element method （FEM） program was obtained by studying the FEM type of the seepage-stress coupling intersection of the RCCD. The method was applied to an actual project, and the results show that the fluid-solid interaction influences dam deformation and dam abutment stability, which is in accordance with practice. Therefore, this model provides a new method for revealing the mechanical behavior of RCCD under the coupling field.
基金supported by the National Natural Science Foundation of China ( 116272109, 11432006)
文摘CD40 receptor and its ligand CD40 L are the members of TNFR and TNF family,respectively.CD40 is expressed on antigen-presenting cells(APC)as a monomer,and would be dimerized upon its oligomerization through binding to its ligand CD40 L.Such dimer formation was shown to be essential for some CD40 signaling events,including phosphoinositide-3 kinase(PI-3 K)activation,the subsequent B7-2 upregulation and the production of IL-8.CD40 L is primarily expressed on activated T cells and activated platelets,and acts as an important costimulatory molecule especially on T follicular helper cells.It is believed that CD40-CD40 L interaction deeply involved in many immune events for the host defense against pathogens and cancer.CD40-CD40 L interaction mediates intracellular signaling along different pathways,such as the canonical and noncanonical nuclear factorκB pathway,mitogen-activated protein kinases,phosphatidylinositol-3 kinase(PI3K)and the phospholipase Cy pathway,is necessary for successful adaptive immune responses mainly relevant to development of CD8+CTLs,and is deeply involved in cross-talks among T cell,B cell,tumor cell,platelet and etc.However,interaction of CD40 with platelet CD40 L would occur in hemodynamics environments,and the regulation of force on this interaction remain unclear.Besides polymerization of CD40,the hemodynamic environment could be believed to regulate interaction between CD40 and its ligand.To reveal the mechanical regulation mechanism of interaction between CD40 L and CD40,atomic force microscope(AFM)was used in the adhesion frequency assay for measuring two-dimensional(2D)kinetics of CD40 L with CD40(the monomer and its dimer)at zero-force and force-clamp assay for measuring single-bond lifetimes of CD40 L/CD40 complex in a range of forces at single-molecule level.AFM cantilever probes were functionalized by incubation with CD40 L in buffer,and soaked in phosphate-buffered saline(PBS)containing 1%bovine serum albumin(BSA)to block nonspecific binding.Polystyrene dishes were coated with CD40(the monomer and its dimer)and then filled with PBS containing 1%BSA.Our data showed that the adhesion frequency of CD40 L with CD40 monomer and its dimer was 0.10 and0. 15,respectively,showing a higher affinity of CD40 L to CD40 dimer rather than its monomer;the rupture force for CD40 L dissociating from CD40 monomer and its dimer was 23 and 31pN,respectively,demonstrating a higher mechanical strength of complex of CD40 L with CD40 dimer instead of monomer;and increasing tension will prolong first and then shorten the bond lifetime of CD40 L-CD40 complex with force threshold of about 1OpN,and dimerization of CD40 had significantly increased enhanced the bond lifetime of CD40 L-CD40 complex,showing a dimerization-enhanced affinity of CD40 to CD40 L and'Catch-Slip'bond mechanism of CD40 L-CD40 interaction.These results suggest that,through upregulating the binding affinity with CD40 L,the polymerization of CD40 stabilizes the linkers and thereby communication between cell and cell,so does the force being small than the force threshold Both CD40 polymerization-and'Catch bond'-induced enhancement of affinity of CD40 with CD40 L may be necessary for stable cross talks between two cells.This finding may be useful for understanding CD40/CD40 L-induced events importantly in physiological or pathological processes at molecular and cellular level.
