1. CNPC Tubular Goods Research Institute, China
2. College of Electronic Information, XiJing University, China
3. North China Petroleum Steel Pipe Co., Ltd, China
4. Shashi Steel Works SINPEC Oilfield Equipment Corporation, China
5. Shandong Shengli Steel Pipe Co.,Ltd, China
6. Nanjing Julong Steel Pipe Co.,Ltd, China