Preparation and Characterization of Polystyrene Magnetic Microspheres via Microsuspention Polymerization Technique
In this study,Fe_3O_4 magnetic nanoparticles dispersed in nano-scale was modified by oleic acid,and thus could be well dispersed in styrene.Polystyrene magnetic microspheres were prepared in a well shaped spherical form with a size range of 15 to 25 μm by the microsuspension polymerization technique for use in the application of biological functional materials.Moreover,the polystyrene magnetic microspheres exhibit stronger magnetic property and superparamagnetism.The morphological,particle size/particle size distribution and magnetic properties of the microspheres were characterized and studied by SEM,IR and magnetometry.
At present, there is a lot of research for slope stability, the inherent reason of slope instability is geotechnical material will get plastic deformation under load. In this paper, Mohr- Coulomb yield condition is transformed strain expressed to stress expressed.Based on this, analysis the effects that geotechnical material parameters internal friction angle ,cohesion c and Poisson's ratio to Mohr- Coulomb yield condition and the development of soil plastic zone.In addition, using the strength reduction FEM simulating the change of plastic zone distribution caused by change of the geotechnical materials parameters .The results show that the internal friction angle , cohesion c are reducted, the plastic zone expand;Increasing the Poisson’s ratio , narrowing the slope’s plastic zone;Plastic zone’s different distribution is caused by different material parameters affect the yield surface.