According to the Bruggeman theory and Maxwell-Garnett theory, the effective dielectric constant of a two-phase random composite with an interfacial shell is presented. The nonlinearity of the theory is obvious. Especi...According to the Bruggeman theory and Maxwell-Garnett theory, the effective dielectric constant of a two-phase random composite with an interfacial shell is presented. The nonlinearity of the theory is obvious. Especially, the theory is suited to study the dielectric properties of two-phase random composites with a spherical interfacial shell. The theoretical results on dielectric properties of polystyrene-barium titanate composites with an interfacial shell are in good agreement with experimental data.展开更多
We construct a density functional theory for two-dimensional electron (hole) gases subjected to both strong magnetic fields and external potentials. In particular, we are focused on regimes near even-denominator fil...We construct a density functional theory for two-dimensional electron (hole) gases subjected to both strong magnetic fields and external potentials. In particular, we are focused on regimes near even-denominator filling factors, in which the systems form composite fermion liquids. Our theory provides a systematic and rigorous approach to determine the properties of ground states in a fractional quantum Hall regime that is modified by artificial structures. We also propose a practical way to construct an approximated functional.展开更多
In this study,a new method is presented to correlate the shear viscosity of nanofluids by local composition theory.The Eyring theory and nonrandom two-liquid(NRTL)equation are used for this purpose.The effects of temp...In this study,a new method is presented to correlate the shear viscosity of nanofluids by local composition theory.The Eyring theory and nonrandom two-liquid(NRTL)equation are used for this purpose.The effects of temperature and particle volume concentration on the viscosity are investigated.The adjustable parameters of NRTL equation are obtained by fitting with experimental data.The calculated shear viscosities for nanofluids of CuO/water with 29 nm particle size,Al2O3/water with two different particle diameters,36 nm and 47 nm,and CuO/(ethylene glycol,water)are compared with experimental data and the average absolute deviation(AAD)is 1.2%,while the results from some conventional models yield an AAD of 190%.The results of this study are in excellent agreement with experimental data.展开更多
In seismic design of tapered high pier, the analysis of natural vibration frequency is of great importance. According to the engineering features of tapered high pier in mountainous area, a vibration calculation model...In seismic design of tapered high pier, the analysis of natural vibration frequency is of great importance. According to the engineering features of tapered high pier in mountainous area, a vibration calculation model was set up considering the tapered pier characteristics and pile-soil interaction. Based on Southwell frequency composition theory, it consists of elastic deformation of bridge pier and the rigid deformation of group piles, which are respectively solved by the finite-element method and energy method, and then the natural frequency is derived. The comparison between the measured and calculated results shows that the calculation errors with and without considering pile-soil interaction are 4.9% and 14.7%, respectively. Additionally, the main parameters (pier height, section variation coefficient and lateral foundation horizontal proportional coefficient) affecting natural frequency were investigated. The result shows that natural frequency ascends with the increase of the lateral foundation horizontal proportional coefficient; and it is quite necessary to consider the pile-soil interaction in natural frequency calculation of tapered high pier.展开更多
A new analytical expression for calculating the wave force on a composite bucket foundation is obtained. Based on the diffraction theory, the analytical solution of the wave pressure and the wave force on the composit...A new analytical expression for calculating the wave force on a composite bucket foundation is obtained. Based on the diffraction theory, the analytical solution of the wave pressure and the wave force on the composite bucket foundation is accurately derived by assigning reasonable boundary conditions. Experiments for the wave pressure on the bucket foundation with a scale of 1:60 under different wave conditions in the wave flume are designed and conducted. The analytical results agree well with the experimental data, and the theoretical approach can accurately predict the wave force on the large-scale structures. The wave pressure distribution on the composite bucket foundation is presented and the influence of the wave height, the water depth and the wave period on the wave force on the composite bucket foundation is investigated. This study provides a quite accurate method to calculate the wave force on a composite bucket foundation, which gives a good framework for future studies of the wave force on other large-scale structures with complex boundaries.展开更多
A visco-plastic rate-dependent homogenization theory for particle-reinforced composites was derived and the equivalent elastic constants and the equivalent visco-plastic parameters of these composites were obtained. A...A visco-plastic rate-dependent homogenization theory for particle-reinforced composites was derived and the equivalent elastic constants and the equivalent visco-plastic parameters of these composites were obtained. A framework of homogenization the- ory for particle-reinforced W-Ni-Fe composites, a kind of tungsten alloy, was established. Based on the homogenization theory and a fixed-point iteration method, a unit cell model with typical microstructnres of the composite was established by using dynamic analysis program. The effects of tungsten content, tungsten particle shape and particle size and interface strength on the mechanical properties and the crack propagation of the W-Ni-Fe composite are analyzed under quasi-static and dynamic loadings. The stress-strain curves of the composite are given and the relation between the macro-mechanical characteristics and the microstructure parameters is explored, which provides an important theoretical basis for the optimization of the W-Ni-Fe composites.展开更多
Constructal theory is introduced into the molten steel yield maximization of a converter in this paper. For the specific total cost of materials, generalized constructal optimization of a converter steel-making proces...Constructal theory is introduced into the molten steel yield maximization of a converter in this paper. For the specific total cost of materials, generalized constructal optimization of a converter steel-making process is performed. The optimal cost distribution of materials is obtained, and is also called as "generalized optimal construct". The effects of the hot metal composition contents, hot metal temperature, slag basicity and ratio of the waste steel price to the sinter ore price on the optimization results are analyzed.The results show that the molten steel yield after optimization is increased by 5.48% compared with that before optimization when sinter ore and waste steel are taken as the coolants, and the molten steel yield is increased by 6.84% when only the sinter ore is taken as the coolant. It means that taking sinter ore as coolant can improve the economic performance of the converter steelmaking process. Decreasing the contents of the silicon, phosphorus and manganese in the hot metal can increase the molten steel yield. The change of slag basicity affects the molten steel yield a little.展开更多
文摘According to the Bruggeman theory and Maxwell-Garnett theory, the effective dielectric constant of a two-phase random composite with an interfacial shell is presented. The nonlinearity of the theory is obvious. Especially, the theory is suited to study the dielectric properties of two-phase random composites with a spherical interfacial shell. The theoretical results on dielectric properties of polystyrene-barium titanate composites with an interfacial shell are in good agreement with experimental data.
基金Supported by the National Basic Research Program of China under Grant No 2012CB921304the National Natural Science Foundation of China under Grant No 11325416
文摘We construct a density functional theory for two-dimensional electron (hole) gases subjected to both strong magnetic fields and external potentials. In particular, we are focused on regimes near even-denominator filling factors, in which the systems form composite fermion liquids. Our theory provides a systematic and rigorous approach to determine the properties of ground states in a fractional quantum Hall regime that is modified by artificial structures. We also propose a practical way to construct an approximated functional.
文摘In this study,a new method is presented to correlate the shear viscosity of nanofluids by local composition theory.The Eyring theory and nonrandom two-liquid(NRTL)equation are used for this purpose.The effects of temperature and particle volume concentration on the viscosity are investigated.The adjustable parameters of NRTL equation are obtained by fitting with experimental data.The calculated shear viscosities for nanofluids of CuO/water with 29 nm particle size,Al2O3/water with two different particle diameters,36 nm and 47 nm,and CuO/(ethylene glycol,water)are compared with experimental data and the average absolute deviation(AAD)is 1.2%,while the results from some conventional models yield an AAD of 190%.The results of this study are in excellent agreement with experimental data.
基金Project(50708033) supported by the National Natural Science Foundation of China
文摘In seismic design of tapered high pier, the analysis of natural vibration frequency is of great importance. According to the engineering features of tapered high pier in mountainous area, a vibration calculation model was set up considering the tapered pier characteristics and pile-soil interaction. Based on Southwell frequency composition theory, it consists of elastic deformation of bridge pier and the rigid deformation of group piles, which are respectively solved by the finite-element method and energy method, and then the natural frequency is derived. The comparison between the measured and calculated results shows that the calculation errors with and without considering pile-soil interaction are 4.9% and 14.7%, respectively. Additionally, the main parameters (pier height, section variation coefficient and lateral foundation horizontal proportional coefficient) affecting natural frequency were investigated. The result shows that natural frequency ascends with the increase of the lateral foundation horizontal proportional coefficient; and it is quite necessary to consider the pile-soil interaction in natural frequency calculation of tapered high pier.
基金supported by the Funds for Creative Research Groups of China(Grant No.51021004)the National Natural Science Foundation of China(Grant No.51509230)
文摘A new analytical expression for calculating the wave force on a composite bucket foundation is obtained. Based on the diffraction theory, the analytical solution of the wave pressure and the wave force on the composite bucket foundation is accurately derived by assigning reasonable boundary conditions. Experiments for the wave pressure on the bucket foundation with a scale of 1:60 under different wave conditions in the wave flume are designed and conducted. The analytical results agree well with the experimental data, and the theoretical approach can accurately predict the wave force on the large-scale structures. The wave pressure distribution on the composite bucket foundation is presented and the influence of the wave height, the water depth and the wave period on the wave force on the composite bucket foundation is investigated. This study provides a quite accurate method to calculate the wave force on a composite bucket foundation, which gives a good framework for future studies of the wave force on other large-scale structures with complex boundaries.
基金supported by the National Natural Science Foundation of China (Grant No. 11032002 and 91016013)the program for New Century Excellent Talents in University+1 种基金National Basic Research Program of China (Grant No. 2010CB832706)the project of State Key Laboratory of Explosion Science and Technology (Beijing Institute of Technology)(Grant No. ZDKT10-03a)
文摘A visco-plastic rate-dependent homogenization theory for particle-reinforced composites was derived and the equivalent elastic constants and the equivalent visco-plastic parameters of these composites were obtained. A framework of homogenization the- ory for particle-reinforced W-Ni-Fe composites, a kind of tungsten alloy, was established. Based on the homogenization theory and a fixed-point iteration method, a unit cell model with typical microstructnres of the composite was established by using dynamic analysis program. The effects of tungsten content, tungsten particle shape and particle size and interface strength on the mechanical properties and the crack propagation of the W-Ni-Fe composite are analyzed under quasi-static and dynamic loadings. The stress-strain curves of the composite are given and the relation between the macro-mechanical characteristics and the microstructure parameters is explored, which provides an important theoretical basis for the optimization of the W-Ni-Fe composites.
基金supported by the National Natural Science Foundation of China(Grant Nos.51506220&51579244)the National Key Basic Research and Development Program of China(Grant No.2012CB720405)
文摘Constructal theory is introduced into the molten steel yield maximization of a converter in this paper. For the specific total cost of materials, generalized constructal optimization of a converter steel-making process is performed. The optimal cost distribution of materials is obtained, and is also called as "generalized optimal construct". The effects of the hot metal composition contents, hot metal temperature, slag basicity and ratio of the waste steel price to the sinter ore price on the optimization results are analyzed.The results show that the molten steel yield after optimization is increased by 5.48% compared with that before optimization when sinter ore and waste steel are taken as the coolants, and the molten steel yield is increased by 6.84% when only the sinter ore is taken as the coolant. It means that taking sinter ore as coolant can improve the economic performance of the converter steelmaking process. Decreasing the contents of the silicon, phosphorus and manganese in the hot metal can increase the molten steel yield. The change of slag basicity affects the molten steel yield a little.