Papers by Author: Bo Yuan

Abstract: 3D porous scaffolds were produced by a combined salt leaching-phase inverse technique. Results showed that micorpores and macropores distributed in the produced scaffolds with high porosity (more than 75%). The interconnectivity can be influenced by the use of methanol and water as a nonsolvent to induce liquidliquid phase separation. The addition of the nonsolvent and NaCl had influence on compression property of the scaffolds.

Abstract: The emulsion combining sol-gel method was used to prepare spherical bioactive glass in the present work. This method involves a two-stage synthesis process: the pre-hydrolysis of tetraethyl orthosilicate (TEOS) in an aqueous acidic solution using templates, and afterward the fabrication of silica spheres by pH induced rapid gelation in a W/O emulsion. Through controlling the two stages separately, the particle size and morphology of silica spheres can be adjusted. These results indicated that emulsion method could supply a good way to prepare glass microspheres.

Abstract: A kind of poly(N-isopropylacrylamide) (PNIPAM) gel was synthesized by radical polymerization of N-isopropylacrylamide monomer in the present of crosslinker N,N-Methylenebisacylamide using short reaction time. This kind of PNIPAM gel exhibits higher swelling ratio at low temperature and much faster deswelling rate than conventional gel, which could be attributed to the presence of loops, dangling chains and other incomplete structure in the gel caused by short reaction time.

Abstract: In this paper, a higher order strain gradient model is constructed to predict this size dependence of the elastic property of nanofibers under uniaxial tensile tests. We can show that the size effects in tensile test can be explained using a new model based on the higher order strain gradient elasticity (HSGE). A series of mechanical testing were performed to verify the model, and good agreement is found between the model prediction and the data obtained in the experiment. Compared with the model prediction based on surface effect (SE), our model can better capture the size effect in tensile test.

Abstract: In this paper, a high order strain gradient (HSGE) model is constructed to predict the bending size dependence of the elastic property of nanofibers under three-point tests. The model can be applied to explain the size dependency in bending test for polymeric nanofibers.

Abstract: A micromechanical model is constructed for the elastic modulus of nano-fibrous scaffold. The nano-fibrous scaffold was obtained using electrospinning method with polymeric materials, and was supposed to be created with linear elastic strain rods that are straight in the range of rod length. Statistical theory was introduced to model the random distribution of fiber segment length and the percolation effect was also studied. Model predictions were verified using experimental data. This model can be used to study the relationship between the elastic modulus of the scaffold with respect to the fiber concentration, fiber diameter and fiber orientation.