1. CNPC Tubular Goods Research Institute No. 89, Jinye Second Road, Yanta District,Department of Pipeline,Xian,Shaanxi,China
2. Changqing Oilfield Branch of China National Petroleum Corporation Changqing Xinglongyuan Community, Weiyang District,Department of Yihuang Natural Gas Project,Xian,Shaanxi,China
3. Lanzhou Branch National Pipeline Network Group Western Pipeline Co., Ltd No. 99, Xiwu Lane, Tianjin North Road, Urumqi,Xinjiang,China