Recently, Coordinate Measuring Machines (CMMs) are widely used to measure roundness errors. Roundness is calculated from a large number of points collected from
Air DTH hammer has been successfully applied in minor-caliber solid mineral exploration,water-well drilling and other drilling areas.In order to expand the appl
Great volumes of shallow-buried (<2,000 m) natural gases which are mainly composed of biogases and low-mature gases have been found in the Mesozoic-Cenozoic sedi