3Yan Wang, Wu Zhang, Xinghui Huo. Study on porous active polyimide copolymer for precision ball-bearing retainer material. Plastics [J]. Rubber and Composites Processing and Applications, 1995, 24: 103-106.
4Prong Guan, Biqin Wang, Deping Lu. Preparation of Microcellular Poly (ethylene terephthalate) and Its Properties[J]. Journal of Applied Polymer Science, 2003,88:1956- 1962.
5Marcherd a M, Meurisse a M- H,Vergnea P,et al.Analysis of Oil Supply Phenomena by Sintered Porous Reservoirs[J]. Tribology Letters, 2001,3(10):163- 170.