水汽凝结体对太赫兹波在大气中的传输衰减起重要作用。结合T-matrix方法,数值模拟了云层中非球形冰晶在太赫兹波段的吸收和散射效应,建立了对称性非球形冰晶的太赫兹波衰减统计模型。分析了不同结构的非球形冰晶的消光特性,对比MPM模型...水汽凝结体对太赫兹波在大气中的传输衰减起重要作用。结合T-matrix方法,数值模拟了云层中非球形冰晶在太赫兹波段的吸收和散射效应,建立了对称性非球形冰晶的太赫兹波衰减统计模型。分析了不同结构的非球形冰晶的消光特性,对比MPM模型的球形水云衰减,结果显示太赫兹波段对称非球形冰晶的散射特性明显,衰减效应强于球形水滴,衰减系数平均为20 d B左右,1 THz以上消光截面随冰晶形状的变化而变化,为太赫兹星地通信提供了参考数据。展开更多
We use the theory based on the gravitational gauge group G to obtain a spherical symmetric solution of the field equations for the gravitational potentials on a Minkowski space-time. The gauge group G is defined and t...We use the theory based on the gravitational gauge group G to obtain a spherical symmetric solution of the field equations for the gravitational potentials on a Minkowski space-time. The gauge group G is defined and then we introduce the gauge-covariant derivative Dμ. The strength tensor of the gravitational gauge field is also obtained and a gauge-invariant Lagrangian including the cosmological constant is constructed. A model whose gravitational gauge potentials A^α μ （x） have spherical symmetry, depending only on the radial coordinate τ is considered and an analytical solution of these equations, which induces the Schwarzschild-de-Sitter metric on the gauge group space, is then determined. All the calculations have been performed by GR Tensor II computer algebra package, running on the Maple V platform, along with several routines that we have written for our model.展开更多
.A new approach for calculating vacuum susceptibilities from an effective quark-quark interaction model is derived. As a special case, the vector vacuum susceptibility is calculated. A comparison with the results of t....A new approach for calculating vacuum susceptibilities from an effective quark-quark interaction model is derived. As a special case, the vector vacuum susceptibility is calculated. A comparison with the results of the previous approaches is given.展开更多
A method for obtaining the low chemical potential dependence of the dressed quark propagator from an effective quark-quark interaction model is developed. Of particular interest here is to give a generalrecipe to find...A method for obtaining the low chemical potential dependence of the dressed quark propagator from an effective quark-quark interaction model is developed. Of particular interest here is to give a generalrecipe to find without arbitrariness the solution representing the "Wigner" phase at non-zero chemical potential for the purpose of studying QCD phase structure.展开更多
There are two kinds of recurrence relations for the spherical functions Pml. The first are those with the same m but different l. Thesecond are those with the same l but different m. The spheroidal functions are exten...There are two kinds of recurrence relations for the spherical functions Pml. The first are those with the same m but different l. Thesecond are those with the same l but different m. The spheroidal functions are extensions of the spherical functions. Recurrencerelations of the first kind are obtained for the spheroidal functions in recent studies. Using the shape invariance method in super-symmetric quantum mechanics, we investigate the second type of recurrence relations for the spheroidal functions. The resultsshow that the second kind of recurrence relation can not be extended to the spheroidal functions.展开更多
Supercapacitors operating in aqueous solutions are low cost energy storage devices with high cycling stability and fast charging and discharging capabilities, but generally suffer from low energy densities. Here, we g...Supercapacitors operating in aqueous solutions are low cost energy storage devices with high cycling stability and fast charging and discharging capabilities, but generally suffer from low energy densities. Here, we grow Ni（OH）2 nanoplates and RuO2 nanoparticles on high quality graphene sheets in order to maximize the specific capacitances of these materials. We then pair up a Ni（OH）2/graphene electrode with a RuO2/graphene electrode to afford a high performance asymmetrical supercapacitor with high energy and power density operating in aqueous solutions at a voltage of -1.5 V. The asymmetrical supercapacitor exhibits significantly higher energy densities than symmetrical RuO2-RuO2 supercapacitors or asymmetrical supercapacitors based on either RuO2- carbon or Ni（OH）2-carbon electrode pairs. A high energy density of -48 W.h/kg at a power density of -0.23 kW/kg, and a high power density of -21 kW/kg at an energy density of N14 W-h/kg have been achieved with our Ni（OH）2/graphene and RuO2/graphene asymmetrical supercapacitor. Thus, pairing up metal-oxide/graphene and metal-hydroxide/graphene hybrid materials for asymmetrical supercapacitors represents a new approach to high performance energy storage.展开更多
In the design and optimization of nanocomposites,the surface/interface stress arising at the inhomogeneity-matrix boundary plays an important role in determining the strength of structures.In this paper,the effect of ...In the design and optimization of nanocomposites,the surface/interface stress arising at the inhomogeneity-matrix boundary plays an important role in determining the strength of structures.In this paper,the effect of surface/interface stress on the dynamic stress around a spherical inhomogeneity subjected to asymmetric dynamic loads is investigated.The surface/interface stress effects are taken into account by introducing Gurtin-Murdoch surface/interface elasticity model.The analytical solutions to displacement potentials are expressed by spherical wave function and associated Legendre function.The dynamic stress concentration factors around the spherical nano-inhomogeneity are illustrated and analyzed.The effects of the incident wave number,and the material properties of the interface and inhomogeneity on the dynamic stress around the inhomogeneity are examined.展开更多
文摘水汽凝结体对太赫兹波在大气中的传输衰减起重要作用。结合T-matrix方法,数值模拟了云层中非球形冰晶在太赫兹波段的吸收和散射效应,建立了对称性非球形冰晶的太赫兹波衰减统计模型。分析了不同结构的非球形冰晶的消光特性,对比MPM模型的球形水云衰减,结果显示太赫兹波段对称非球形冰晶的散射特性明显,衰减效应强于球形水滴,衰减系数平均为20 d B左右,1 THz以上消光截面随冰晶形状的变化而变化,为太赫兹星地通信提供了参考数据。
文摘We use the theory based on the gravitational gauge group G to obtain a spherical symmetric solution of the field equations for the gravitational potentials on a Minkowski space-time. The gauge group G is defined and then we introduce the gauge-covariant derivative Dμ. The strength tensor of the gravitational gauge field is also obtained and a gauge-invariant Lagrangian including the cosmological constant is constructed. A model whose gravitational gauge potentials A^α μ （x） have spherical symmetry, depending only on the radial coordinate τ is considered and an analytical solution of these equations, which induces the Schwarzschild-de-Sitter metric on the gauge group space, is then determined. All the calculations have been performed by GR Tensor II computer algebra package, running on the Maple V platform, along with several routines that we have written for our model.
文摘.A new approach for calculating vacuum susceptibilities from an effective quark-quark interaction model is derived. As a special case, the vector vacuum susceptibility is calculated. A comparison with the results of the previous approaches is given.
文摘A method for obtaining the low chemical potential dependence of the dressed quark propagator from an effective quark-quark interaction model is developed. Of particular interest here is to give a generalrecipe to find without arbitrariness the solution representing the "Wigner" phase at non-zero chemical potential for the purpose of studying QCD phase structure.
基金supported by the National Natural Science Foundation of China (Grant No. 10875018)the National Basic Research Program of China (Grant No. 2010CB923200)
文摘There are two kinds of recurrence relations for the spherical functions Pml. The first are those with the same m but different l. Thesecond are those with the same l but different m. The spheroidal functions are extensions of the spherical functions. Recurrencerelations of the first kind are obtained for the spheroidal functions in recent studies. Using the shape invariance method in super-symmetric quantum mechanics, we investigate the second type of recurrence relations for the spheroidal functions. The resultsshow that the second kind of recurrence relation can not be extended to the spheroidal functions.
文摘Supercapacitors operating in aqueous solutions are low cost energy storage devices with high cycling stability and fast charging and discharging capabilities, but generally suffer from low energy densities. Here, we grow Ni（OH）2 nanoplates and RuO2 nanoparticles on high quality graphene sheets in order to maximize the specific capacitances of these materials. We then pair up a Ni（OH）2/graphene electrode with a RuO2/graphene electrode to afford a high performance asymmetrical supercapacitor with high energy and power density operating in aqueous solutions at a voltage of -1.5 V. The asymmetrical supercapacitor exhibits significantly higher energy densities than symmetrical RuO2-RuO2 supercapacitors or asymmetrical supercapacitors based on either RuO2- carbon or Ni（OH）2-carbon electrode pairs. A high energy density of -48 W.h/kg at a power density of -0.23 kW/kg, and a high power density of -21 kW/kg at an energy density of N14 W-h/kg have been achieved with our Ni（OH）2/graphene and RuO2/graphene asymmetrical supercapacitor. Thus, pairing up metal-oxide/graphene and metal-hydroxide/graphene hybrid materials for asymmetrical supercapacitors represents a new approach to high performance energy storage.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11172185 and 10972147)the Natural Science Foundation of Hebei Province,China (Grant No. A2010001052)the Program for Changjiang Scholars and Innovative Research Team in University(Grant No. IRT0971)
文摘In the design and optimization of nanocomposites,the surface/interface stress arising at the inhomogeneity-matrix boundary plays an important role in determining the strength of structures.In this paper,the effect of surface/interface stress on the dynamic stress around a spherical inhomogeneity subjected to asymmetric dynamic loads is investigated.The surface/interface stress effects are taken into account by introducing Gurtin-Murdoch surface/interface elasticity model.The analytical solutions to displacement potentials are expressed by spherical wave function and associated Legendre function.The dynamic stress concentration factors around the spherical nano-inhomogeneity are illustrated and analyzed.The effects of the incident wave number,and the material properties of the interface and inhomogeneity on the dynamic stress around the inhomogeneity are examined.
