The acoustic wave band structures and single defect states of the two-dimensional periodic composite media of water(mercury)cylinders with circular cross section in mercury(water)host was studied by using the plane-wa...The acoustic wave band structures and single defect states of the two-dimensional periodic composite media of water(mercury)cylinders with circular cross section in mercury(water)host was studied by using the plane-waves method and supercell calculations.We find that the numbers of the gaps in the first 50 bands vs filling fraction have the similar results as gap/midgap ratio of the lowest gap in the period systems.Only one band gap exhibits in wide range of filling fraction,and several defect states are created inside the band gaps in single defect system.The influences of filling fraction and defect radius on the band structure are investigated.展开更多
The electrorheological properties of a model system consisting of metal particles with insulating coating in a dielectric oil are analyzed by extending Rayleigh identity based on a multipole expansion theory.Evaluatio...The electrorheological properties of a model system consisting of metal particles with insulating coating in a dielectric oil are analyzed by extending Rayleigh identity based on a multipole expansion theory.Evaluation of the effective dielectric constant is emphasized.The dependence of the shear stressтon the shear strainθand the shear modulus G for the electrorheological solid is presented.It is found that the model system shows much higher electrorheological performance than the traditional suspensions.展开更多
Spontaneous rupture of some polymer films upon heating is commonplace. The very criterion for this instability is the system free energy possessing a negative curvature. Within the framework of full frequency-dependen...Spontaneous rupture of some polymer films upon heating is commonplace. The very criterion for this instability is the system free energy possessing a negative curvature. Within the framework of full frequency-dependent theory of dispersion forces, we have derived the excess free energy of a typical system--polystyrene film deposited on the silicon substrate. The excess free energy, wavelengths and growth rates are calculate and a comparison is made between the accurate results and the approximate results. It is found that the stability of the fihn can be tuned by the variation of the thickness of the coating and the retardation effects can be significant sometimes.展开更多
The Rayleigh identity based on a multipole expansion theory is extended to analyze the mechanical properties of electrorheological fluids.Evaluation of the effective dielectric constant is emphasized.The dependence of...The Rayleigh identity based on a multipole expansion theory is extended to analyze the mechanical properties of electrorheological fluids.Evaluation of the effective dielectric constant is emphasized.The dependence of the shear stress on the shear strain and the shear modulus for chains of particles arranged on a square lattice are presented.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.19874021the Natural Science Foundation of Guangdong Province(Grant No.000037).
文摘The acoustic wave band structures and single defect states of the two-dimensional periodic composite media of water(mercury)cylinders with circular cross section in mercury(water)host was studied by using the plane-waves method and supercell calculations.We find that the numbers of the gaps in the first 50 bands vs filling fraction have the similar results as gap/midgap ratio of the lowest gap in the period systems.Only one band gap exhibits in wide range of filling fraction,and several defect states are created inside the band gaps in single defect system.The influences of filling fraction and defect radius on the band structure are investigated.
基金Supported by the National Natural Science Foundation of China under Grant No.19874021in part by the Foundation of Educational Commit tee of Hu'nan Province of China under Grant No.98B087.
文摘The electrorheological properties of a model system consisting of metal particles with insulating coating in a dielectric oil are analyzed by extending Rayleigh identity based on a multipole expansion theory.Evaluation of the effective dielectric constant is emphasized.The dependence of the shear stressтon the shear strainθand the shear modulus G for the electrorheological solid is presented.It is found that the model system shows much higher electrorheological performance than the traditional suspensions.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50425206, 10418014 and 10174054, the Doctoral Research Foundation of the Ministry of Education of China under Grant No 20020486013, and the Natural Science Foundation of Hunan Province under Grant No 04JJ3079.
基金Project supported by the Natural Science Foundation of Hu＇nan Province, China （Grant No 00JJY2072）, and the Foundation of Educational Committee of Hu＇nan Province, China （Grant Nos 00C189 and 01B019）.
文摘Spontaneous rupture of some polymer films upon heating is commonplace. The very criterion for this instability is the system free energy possessing a negative curvature. Within the framework of full frequency-dependent theory of dispersion forces, we have derived the excess free energy of a typical system--polystyrene film deposited on the silicon substrate. The excess free energy, wavelengths and growth rates are calculate and a comparison is made between the accurate results and the approximate results. It is found that the stability of the fihn can be tuned by the variation of the thickness of the coating and the retardation effects can be significant sometimes.
基金Supported by the National Natural Science Foundation of China under Grant No.19574016the Guangdong Provincial Natural Science Foundation of China under Grant No.930939。
文摘The Rayleigh identity based on a multipole expansion theory is extended to analyze the mechanical properties of electrorheological fluids.Evaluation of the effective dielectric constant is emphasized.The dependence of the shear stress on the shear strain and the shear modulus for chains of particles arranged on a square lattice are presented.
