To counter the reasonable selection of blast parameters in the process of coal production in a composite coal seam face, a series of on-the-spot tests were conducted.
针对复合煤层回采工作面煤炭生产过程中爆破参数的合理选取问题，进行了一系列现场试验。
2
British experts delivered a strong counter - blast to the Professor's claims.
英国专家对该教授的断言进行了强烈驳斥。
3
Blast furnace is a complex metallurgical reactor with gas-solid counter flow.