The long-term storage of phosphate tailings will occupy a large amount of land,pollute soil and groundwater,thus,it is crucial to achieve the harmless disposal of phosphate tailings.In this study,high-performance geop...The long-term storage of phosphate tailings will occupy a large amount of land,pollute soil and groundwater,thus,it is crucial to achieve the harmless disposal of phosphate tailings.In this study,high-performance geopolymers with compressive strength of 38.8 MPa were prepared by using phosphate tailings as the main raw material,fly ash as the active silicon-aluminum material,and water glass as the alkaline activator.The solid content of phosphate tailings and fly ash was 60% and 40%,respectively,and the water-cement ratio was 0.22.The results of XRD,FTIR,SEM-EDS and XPS show that the reactivity of phosphate tailings with alkaline activator is weak,and the silicon-aluminum material can react with alkaline activator to form zeolite and gel,and encapsulate/cover the phosphate tailings to form a dense phosphate tailings-based geopolymer.During the formation of geopolymers,part of the aluminum-oxygen tetrahedron replaced the silicon-oxygen tetrahedron,causing the polycondensation reaction between geopolymers and increasing the strength of geopolymers.The leaching toxicity test results show that the geopolymer has a good solid sealing effect on heavy metal ions.The preparation of geopolymer from phosphate tailings is an important way to alleviate the storage pressure and realize the resource utilization of phosphate tailings.展开更多
An important step for achieving the knowledge-based design freedom on nano-and interfacial materials is attained by elucidating the related surface and interface thermodynamics from the first principles so as to allow...An important step for achieving the knowledge-based design freedom on nano-and interfacial materials is attained by elucidating the related surface and interface thermodynamics from the first principles so as to allow engineering the microstructures for desired properties through smartly designing fabrication processing parameters.This is demonstrated for SnO2 nano-particle surfaces and also a technologically important Ag-SnO2 interface fabricated by in-situ internal oxidation.Based on defect thermodynamics,we first modeled and calculated the equilibrium surface and interface structures,and as well corresponding properties,as a function of the ambient temperature and oxygen partial pressure.A series of first principles energetics calculations were then performed to construct the equilibrium surface and interface phase diagrams,to describe the environment dependence of the microstructures and properties of the surfaces and interfaces during fabrication and service conditions.The use and potential application of these phase diagrams as a process design tool were suggested and discussed.展开更多
The Brownian dynamics （BD） simulation of a dilute surfactant solution is conducted in a steady shear flow. The rodlike micelle is assumed as a rigid rod composed of lined-up beads. A novel intercluster potential mod...The Brownian dynamics （BD） simulation of a dilute surfactant solution is conducted in a steady shear flow. The rodlike micelle is assumed as a rigid rod composed of lined-up beads. A novel intercluster potential model is introduced for describing the interactions between, micelles. In the model, the Lennard-Jones and the soft-sphere potentials are used as inter-bead potentials for end-end and interior-interior beads, respectively. The micelles are combined at their ends to form a network structure at lower shear rates and are disconnected to become more and more parallel to the shear flow direction with increasing shear rate. The change of micellar microstructures with the variation of the shear rate results in shear thinning characteristics of the computed shear viscosities and first normal stress difference coefficients. The effects of surfactant solution concentration on the micellar structures and rheological properties are also investigated. Results show that the shear viscosities and the first normal stress difference coefficients increase with increasing the viscosity of the surfactant solution.展开更多
The influence of petroleum sulphonate (TRS) on interfacial properties and stability of the emulsions formed by formation water and asphaltene, resin and crude model oils from Gudong crude oil was investigated by measu...The influence of petroleum sulphonate (TRS) on interfacial properties and stability of the emulsions formed by formation water and asphaltene, resin and crude model oils from Gudong crude oil was investigated by measurement of interfacial shear viscosity, interfacial tension (IFT) and emulsion stability. With increasing petroleum sulphonate concentration, IFT between the formation water and the asphaltene, resin and crude model oils decreases significantly. The interfacial shear viscosity and emulsion stability of asphaltene and crude model oil system increase for the petroleum sulphonate concentration in the range 0.1% to 0.3%, and decrease slightly when the concentration of the surfactant is 0.5%. There exists a close correlation between the interfacial shear viscosity and the stability of the emulsions formed by asphaltene or crude model oils and petroleum sulphonate solution.The stability of the emulsions is determined by the strength of the interfacial film formed of petroleum sulphonate molecules and the natural interfacial active components in the asphaltene fraction and the crude oil. The asphaltene in the crude oil plays a major role in determining the interfacial properties and the stability of the emulsions.展开更多
The Kirchhoff thin elastic rod models are always the important basis to explore the configuration mecha- nism of the flexible structures in both the macroscopic and microscopic scale. As a continuum model of DNA, a th...The Kirchhoff thin elastic rod models are always the important basis to explore the configuration mecha- nism of the flexible structures in both the macroscopic and microscopic scale. As a continuum model of DNA, a thin elastic rod subjected to interfacial interactions is used to investigate the helical equilibrium configuration of DNA in salt solution. In this paper, the Kirchhoff＇s equations in the presence of interracial traction and the free energy density functions of different configurations are studied. The transition formula of the free energy between B-DNA and Z- DNA is obtained, and the results show that the free energy of the transition is mainly determined by the salt concentra- tion, which agrees well with the experimental data.展开更多
This paper concerns a system of equations describing the vibrations of a planar network of nonlinear Timoshenko beams. The authors derive the equations and appropriate nodal conditions, determine equilibrium solutions...This paper concerns a system of equations describing the vibrations of a planar network of nonlinear Timoshenko beams. The authors derive the equations and appropriate nodal conditions, determine equilibrium solutions and, using the methods of quasilinear hyperbolic systems, prove that for tree-like networks the natural initial-boundary value problem admits semi-global classical solutions in the sense of Li [Li, T. T., Controllability and Observability for Quasilinear Hyperbolic Systems, AIMS Ser. Appl. Math., vol 3,American Institute of Mathematical Sciences and Higher Education Press, 2010] existing in a neighborhood of the equilibrium solution. The authors then prove the local exact controllability of such networks near such equilibrium configurations in a certain specified time interval depending on the speed of propagation in the individual beams.展开更多
基金Project(202202AG050010)supported by the Yunnan Major Scientific and Technological Projects,ChinaProject(202103AA080007)supported by the Key R&D Project of Science and Technology Department of Yunnan Province,ChinaProject(NECP2023-06)supported by the Open Project Fund of National Engineering and Technology Research Center for Development&Utilization of Phosphorous Resources,China。
文摘The long-term storage of phosphate tailings will occupy a large amount of land,pollute soil and groundwater,thus,it is crucial to achieve the harmless disposal of phosphate tailings.In this study,high-performance geopolymers with compressive strength of 38.8 MPa were prepared by using phosphate tailings as the main raw material,fly ash as the active silicon-aluminum material,and water glass as the alkaline activator.The solid content of phosphate tailings and fly ash was 60% and 40%,respectively,and the water-cement ratio was 0.22.The results of XRD,FTIR,SEM-EDS and XPS show that the reactivity of phosphate tailings with alkaline activator is weak,and the silicon-aluminum material can react with alkaline activator to form zeolite and gel,and encapsulate/cover the phosphate tailings to form a dense phosphate tailings-based geopolymer.During the formation of geopolymers,part of the aluminum-oxygen tetrahedron replaced the silicon-oxygen tetrahedron,causing the polycondensation reaction between geopolymers and increasing the strength of geopolymers.The leaching toxicity test results show that the geopolymer has a good solid sealing effect on heavy metal ions.The preparation of geopolymer from phosphate tailings is an important way to alleviate the storage pressure and realize the resource utilization of phosphate tailings.
基金Project(51171211) supported by the National Natural Science Foundation of ChinaProject(NCET-10-0837) supported by the Chinese Ministry of Education's Supportive Program for New Century Excellent Talents in UniversitiesProject(2006BAE03B03) supported by the Chinese National Science and Technology Supportive Program
文摘An important step for achieving the knowledge-based design freedom on nano-and interfacial materials is attained by elucidating the related surface and interface thermodynamics from the first principles so as to allow engineering the microstructures for desired properties through smartly designing fabrication processing parameters.This is demonstrated for SnO2 nano-particle surfaces and also a technologically important Ag-SnO2 interface fabricated by in-situ internal oxidation.Based on defect thermodynamics,we first modeled and calculated the equilibrium surface and interface structures,and as well corresponding properties,as a function of the ambient temperature and oxygen partial pressure.A series of first principles energetics calculations were then performed to construct the equilibrium surface and interface phase diagrams,to describe the environment dependence of the microstructures and properties of the surfaces and interfaces during fabrication and service conditions.The use and potential application of these phase diagrams as a process design tool were suggested and discussed.
文摘The Brownian dynamics （BD） simulation of a dilute surfactant solution is conducted in a steady shear flow. The rodlike micelle is assumed as a rigid rod composed of lined-up beads. A novel intercluster potential model is introduced for describing the interactions between, micelles. In the model, the Lennard-Jones and the soft-sphere potentials are used as inter-bead potentials for end-end and interior-interior beads, respectively. The micelles are combined at their ends to form a network structure at lower shear rates and are disconnected to become more and more parallel to the shear flow direction with increasing shear rate. The change of micellar microstructures with the variation of the shear rate results in shear thinning characteristics of the computed shear viscosities and first normal stress difference coefficients. The effects of surfactant solution concentration on the micellar structures and rheological properties are also investigated. Results show that the shear viscosities and the first normal stress difference coefficients increase with increasing the viscosity of the surfactant solution.
基金国家重点基础研究发展计划(973计划)，an International Cooperation Research Program
文摘The influence of petroleum sulphonate (TRS) on interfacial properties and stability of the emulsions formed by formation water and asphaltene, resin and crude model oils from Gudong crude oil was investigated by measurement of interfacial shear viscosity, interfacial tension (IFT) and emulsion stability. With increasing petroleum sulphonate concentration, IFT between the formation water and the asphaltene, resin and crude model oils decreases significantly. The interfacial shear viscosity and emulsion stability of asphaltene and crude model oil system increase for the petroleum sulphonate concentration in the range 0.1% to 0.3%, and decrease slightly when the concentration of the surfactant is 0.5%. There exists a close correlation between the interfacial shear viscosity and the stability of the emulsions formed by asphaltene or crude model oils and petroleum sulphonate solution.The stability of the emulsions is determined by the strength of the interfacial film formed of petroleum sulphonate molecules and the natural interfacial active components in the asphaltene fraction and the crude oil. The asphaltene in the crude oil plays a major role in determining the interfacial properties and the stability of the emulsions.
基金Supported by the National Nature Science Foundation of China(No.11372210)the Research Fund for the Doctoral Program of Higher Education of China(No.20120032110010)Tianjin Research Program of Application Foundation and Advanced Technology(No.12JCZDJC28000)
文摘The Kirchhoff thin elastic rod models are always the important basis to explore the configuration mecha- nism of the flexible structures in both the macroscopic and microscopic scale. As a continuum model of DNA, a thin elastic rod subjected to interfacial interactions is used to investigate the helical equilibrium configuration of DNA in salt solution. In this paper, the Kirchhoff＇s equations in the presence of interracial traction and the free energy density functions of different configurations are studied. The transition formula of the free energy between B-DNA and Z- DNA is obtained, and the results show that the free energy of the transition is mainly determined by the salt concentra- tion, which agrees well with the experimental data.
基金supported by the National Basic Research Program of China(No.2103CB834100)the National Science Foundation of China(No.11121101)+1 种基金the National Natural Sciences Foundation of China(No.11101273)the DFG-Cluster of Excellence:Engineering of Advanced Materials
文摘This paper concerns a system of equations describing the vibrations of a planar network of nonlinear Timoshenko beams. The authors derive the equations and appropriate nodal conditions, determine equilibrium solutions and, using the methods of quasilinear hyperbolic systems, prove that for tree-like networks the natural initial-boundary value problem admits semi-global classical solutions in the sense of Li [Li, T. T., Controllability and Observability for Quasilinear Hyperbolic Systems, AIMS Ser. Appl. Math., vol 3,American Institute of Mathematical Sciences and Higher Education Press, 2010] existing in a neighborhood of the equilibrium solution. The authors then prove the local exact controllability of such networks near such equilibrium configurations in a certain specified time interval depending on the speed of propagation in the individual beams.
