Let p,q>0 and composition operator Cφ be defined as (Cφf)(z)=f(φ(z)),with the help of a suitable testing function(Proposition 1),a lower estimate of the essential norm of a bounded composition operator Cφinduced by φ between p-Bloch space βp(Bn) and q-Bloch space βq(Bn) is given(Theorem 1).

We express the essential norm of a weighted composition operator on weighted Bergman spaces of the unit ball in terms of an asymptotic upper bound of a quantity.

In this paper,characteristic tilting modules over path alyebras of D_n is defined.

Based on the analysis of polymer solution flowing in throat model,the viscous-elastic constitutive model of the polymer solution seepage is established in which the characteristics of the polymer solution and porous media are all considered.

Initial discussion on pyrophyllite plastic constitutive model;

In his paper,the Drucker-Prager model,a plastic constitutive model was adopted to represent the stress strain relationship of soil.

Based on the analyses of the investigated results and the physical meaning of the viscous-plastic constitution mo-del containing various internal variables, a one-dimension viscous-plastic constitution model for aluminum foam was recommended and then fitted.