*

*

Recently, lots of attention and researches have been paid to the viscoelastic instabilities which are generated by the interaction between the elastic stress and inertial stress and even can emerge at extremely low Reynolds number (Re) different from Newtonian instabilities. When the elasticity number (defined as the ratio between Deborah number and Reynolds number) is significant, the purely elastic instabilities would happen at Re << ReC, where ReC is the critical Re of inertial instabilities i.e. the inertial stress is negligible. Generally, the visoelastic fluids are characterized by a complicated rheological properties such as memory properties, shear-thinning and non-zero normal stress difference and so on. Nonetheless, based on various experiments, theoretical analysis and numerical simulation, general understanding of the phenomenon has been achieved. In the paper we make a review on the development of the research on purely elastic instabilities mainly from the experimental and theoretical viewpoint. It is organized as the following categories：the introduction of the viscoelastic fluids, the development and results obtained from experiments (such as Taylor-Couette flows, cone-and-plate flows and plate-and-plate flows), and the development and results from theoretical analysis (such as linear and nonlinear stability analysis, direct numerical simulation, gradient energy theory and so on). Then summaries of the purely elastic instability mechanism, evolvement and the influencing factors are achieved based on the results from experiments and theoretical analysis. In the end we proposed the existing problems and suggestions for future work.

Carbon dioxide storage is an effective method for utilizing greenhouse gas and reducing greenhouse gas discharge. Nevertheless, escape of carbon dioxide through cap rock after sequestration will cause disasters such as upheaving or sinking of the ground surface, water pollution, breakage of oceanic ecosystem, greenhouse effect et al. In this paper, research advances on carbon dioxide storage and escape is summarized in significance. Three important storage forms are introduced, furthermore, escape form of carbon dioxide and key parameters are analyzed. It is shown that two important problems are needed to investigate further: (1) basic parameters in carbon dioxide escape are needed to determined by model experiments. (2) models of multi-phase flow considering chemical reaction, stratum characteristics, well distribution characteristics are needed considered. (3) not only diffusion and seepage, but also increase of seepage due to well distribution and crack formation by high gas pressure are needed to consider.

This paper reviews some recent results of the key project entitled “Mechanics research of some problems of functionally graded materials and structures” supported by the National Natural Science Foundation of China. The progress is highlighted in the following aspects: the analytical and the semi-analytical solutions of functionally graded beams, plates and shells as well as their simplified theories, fracture analysis of functionally graded materials, a micro-element method for the macro-micro scale analysis and the optimal design of functionally graded structures. Perspective is also made for future directions of mechanics analysis of functionally graded materials and structures

To osseous tissue, the normal physiological activity can lead to local deformation ( strain),micro trauma, piezoelectric potentials, fluid flowing in bone canaliculus and streaming potentials. Bone’s Stress-Generated Potentials (SGP) mainly includes piezoelectric effect and electrokinetic effect. With the development of bone biomechanics, SGP research methods were improved greatly. In this article, research methods and advance of SGP in bone、bone substitute、dentin will be reviewed.

*

*

*