Aim To study the relationships between average molecular mass and intrinsic viscosity of polyanhydrides. Methods With chloroform as solvent and petroleum ether as the precipitating agent polyanhydride was separated in...Aim To study the relationships between average molecular mass and intrinsic viscosity of polyanhydrides. Methods With chloroform as solvent and petroleum ether as the precipitating agent polyanhydride was separated into a series of grades with different average molecular mass. The absolute average molecular mass (M) and intrinsic viscosity ([]) of every grade were measured. Results and Conclusion The relationships between [] and M of three typical polyanhydrides were obtained from bi-logarithm coordinate plotting of [] versus M.展开更多
A moisture-content based constitutive model was proposed based on the hyperbolic model as an attempt to move towards the implementation of unsaturated soil mechanics into routine geotechnical engineering practice. The...A moisture-content based constitutive model was proposed based on the hyperbolic model as an attempt to move towards the implementation of unsaturated soil mechanics into routine geotechnical engineering practice. The stress-strain behavior of in-situ soil at a depth of 5 m was investigated by conducting undrained triaxial compression tests using the remolded soil samples. The test results show that the stress-strain relationship of unsaturated cohesive soil is still hyperbolic. The values of parameters a and b given in the model decrease with increasing the confining pressure for soil samples with the same moisture content and increase with increasing the moisture content for soil samples under the same confining pressure. The relationships between parameters a, b and moisture content were studied for confining pressures of 100, 150, 200 and 250 kPa. The comparison between the measured and predicted stress-strain curves for an additional group of soil samples, having a moisture content of 25.4%, shows that the proposed moisture content-dependent hyperbolic model provides a good prediction of stress-strain behavior of unsaturated cohesive soil.展开更多
The equation of motion of a viscoelastic rod of density rod p is considered when the Constitutive Relationships contains fractional derivatives （in the Riemann-Liouville sense） of order β, 0 ≤ β ≤ 1. The solutio...The equation of motion of a viscoelastic rod of density rod p is considered when the Constitutive Relationships contains fractional derivatives （in the Riemann-Liouville sense） of order β, 0 ≤ β ≤ 1. The solution of this equation is given in a general case. It is shown that for the limit values of the derivative index ,β, i.e. when β = 0 or β = 1, the general solution gives rise to classical solutions of hyperbolic and parabolic equations.展开更多
The shear viscosity bound violation in Einstein gravity for anisotropic black branes is discussed, with the aim of constraining the deviation of the shear viscosity-entropy density ratio from the shear viscosity bound...The shear viscosity bound violation in Einstein gravity for anisotropic black branes is discussed, with the aim of constraining the deviation of the shear viscosity-entropy density ratio from the shear viscosity bound using causality and thermodynamics analysis.The results show that no stringent constraints can be imposed. The diffusion bound in anisotropic plaases is also studied. Ultimately, it is concluded that shear viscosity violation always occurs in cases where the equation of motion of the metric fluctuations cannot be written in a form identical to that of the minimally coupled massless scalar fields.展开更多
文摘Aim To study the relationships between average molecular mass and intrinsic viscosity of polyanhydrides. Methods With chloroform as solvent and petroleum ether as the precipitating agent polyanhydride was separated into a series of grades with different average molecular mass. The absolute average molecular mass (M) and intrinsic viscosity ([]) of every grade were measured. Results and Conclusion The relationships between [] and M of three typical polyanhydrides were obtained from bi-logarithm coordinate plotting of [] versus M.
基金Project(50608038) supported by the National Natural Science Foundation of China
文摘A moisture-content based constitutive model was proposed based on the hyperbolic model as an attempt to move towards the implementation of unsaturated soil mechanics into routine geotechnical engineering practice. The stress-strain behavior of in-situ soil at a depth of 5 m was investigated by conducting undrained triaxial compression tests using the remolded soil samples. The test results show that the stress-strain relationship of unsaturated cohesive soil is still hyperbolic. The values of parameters a and b given in the model decrease with increasing the confining pressure for soil samples with the same moisture content and increase with increasing the moisture content for soil samples under the same confining pressure. The relationships between parameters a, b and moisture content were studied for confining pressures of 100, 150, 200 and 250 kPa. The comparison between the measured and predicted stress-strain curves for an additional group of soil samples, having a moisture content of 25.4%, shows that the proposed moisture content-dependent hyperbolic model provides a good prediction of stress-strain behavior of unsaturated cohesive soil.
文摘The equation of motion of a viscoelastic rod of density rod p is considered when the Constitutive Relationships contains fractional derivatives （in the Riemann-Liouville sense） of order β, 0 ≤ β ≤ 1. The solution of this equation is given in a general case. It is shown that for the limit values of the derivative index ,β, i.e. when β = 0 or β = 1, the general solution gives rise to classical solutions of hyperbolic and parabolic equations.
基金the National Natural Science Foundation of China(Grant No.11375110)
文摘The shear viscosity bound violation in Einstein gravity for anisotropic black branes is discussed, with the aim of constraining the deviation of the shear viscosity-entropy density ratio from the shear viscosity bound using causality and thermodynamics analysis.The results show that no stringent constraints can be imposed. The diffusion bound in anisotropic plaases is also studied. Ultimately, it is concluded that shear viscosity violation always occurs in cases where the equation of motion of the metric fluctuations cannot be written in a form identical to that of the minimally coupled massless scalar fields.
