A crawler, device of girth welds testing outside pipeline is developed successfully.成功地研制了管道外检测机械装置—爬行器.The pool is divided into three sections with a crawler lane for beginners.泳池分三部分，有为初学者而设的慢泳道。The Google crawler does...
The pool is divided into three sections with a crawler lane for beginners.泳池分三部分，有为初学者而设的慢泳道。A crawler, device of girth welds testing outside pipeline is developed successfully.成功地研制了管道外检测机械装置—爬行器.The Google crawler does...
在煤岩的分类中,有腐殖煤和腐泥煤之分.Coal rock can be classified as humic and sapropelic coal.黄县煤田第三纪腐殖煤 、 藻烛煤、油页岩显微组分富含树脂体.Resinite is a rich n 1 aceral in Teriary humic coal, boghead - cannel coal and oil shale fromHuangxian Coalfield....