Papers by Author: Yi Wang

Abstract: Ni8W alloy ingots were prepared by SPS technic, followed by homogenizing, cold rolling and recrystallization annealing. The influence of ball milling on cold rolling and cube texture formation of Ni8W alloy substrates was investigated during the course of preparation. Finally, high quality cube-textured Ni8W alloy substrates were successfully obtained using this powder metallurgy process, and characterized by electron backscatter diffraction technic. It indicated that the cube texture fraction was as high as 90% (<10^o) when it annealed at 1350°C for 2 h.

Abstract: Hydroxyapatite/polymer scaffolds with proper biomechanical properties and stable 3-D porous structure were fabricated by combining gas foaming with solvent-casting/particle-leaching technique, in which novel solid H2O2 were used as a porogen. During the manufacturing process, we found that the porosity, compressive strength and microstructure of the composites are varied from each other while different solvents (dichloromethane, acetone, chloroform and 1,4-dioxane) were used. Porosities of the specimens increase from 72±5 to 87±5% in accordance with the increase of boiling point from 39.75 to 101.32 °C, while compressive strength decreased (4.8±0.7- 0.5±0.3 MPa). Interactions of HA/solvent and PLA/solvent together with evaporation dynamic tests of different solvents were investigated. The results show that the evaporation rate of the solvents is the most important factor affecting the final properties of the scaffolds.

Abstract: GTR treatment alone has not led to predictable new periodontal tissue reconstruction. Recently, various types of tissue substitutes and alloplastic graft have been used in conjunction with the GTR technique. The aim of this study was to evaluate whether nano-hydroxyapatite/Polylactic acid (nHA/PLA) and bone-derived materials would be useful in the treatment of class II furcation, in order to provide an ideal bone replacement material for periodontal treatment. Mucoperiosteal flap was raised on the buccal aspects of the experimental teeth and class Ⅱ furcation defects were created surgically on premolars of each quadrant in 3 dogs. The defects were randomly repaired with nHA/PLA and collagenic membrane, partially deproteinized bone (PDPB) and collagenic membrane. Blank control group was stayed. Speciments obtained in 6 weeks were evaluated with general observation, histological microscopic analysis. The specimens of the implanted groups exhibited periodontal regeneration including newly formed cementum, periodontal ligament and new bone. The new-formed bone area in sites receiving nHA/PLA and PDPB combined with collagen membrane was greater than that in blank group.The new bone area in PDPB was smaller than that in nHA/PLA. nHA/PLA would be better alternative for periodontal regeneration.

Abstract: A new way to prepare polymer/hydroxyapatite(HA) composite scaffolds with 3-D interconnected macro and micro pores at room temperature was established, basically based on solvent-casting and particle-leaching together with foaming technique. With this method, Polylactide (PLA) / HA composites of porous architecture with macro pores (50~300)m, average 200)m) and micro pores (~10)m) on the skeleton were obtained. The bending strength and the compressive strength of the composite scaffold were reached to 11.5 MPa and 7MPa respectively with the porosity of approximate to 90%. The study supplied a new short time, low energyexpending method to prepare polymer/ceramic composite with high porosity and interconnected porous structure at room temperature.