the heat transfer between residential units is a difficult technical problem in heat metering of central heating systems.
户间传热是集中供暖热计量中的一个技术难题。
casing damage is a difficult technical problem and puzzle oil field for a long period.
油田套损是石油工程中的一大技术难题,多年来困扰着各油田。
drilling hole slanting question is a quite complex question in the drilling technology. hole curving is a difficult technical problem and a formidable matter regarding us which is urgent to solve.
孔斜问题,在鉆探技术上是一个比较复杂的问题,孔斜这一课题对于我们是一个重要而又迫切需要解决的技术难题。