%0 Conference Proceedings %T Effect of polyethylene glycol and acetic acid on morphology of nanoparticle Hydroxyapatite synthesized by sol-gel %A Yousefi, Khadijeh %A Zebarjad, Seyed Mojtaba %A Vahdati Khaki, Jalil %J 4th International Conference on Nanostructures (ICNS4 %D 2012