The ledo road and the pipeline went through some mostly uninhabited areas of burma with some of the most difficult terrain in the world , including tropical rain forest , torrential streams , terraces and canyons , jungle - covered mountains and swampy valleys 利多公路和输油管道线经过一些缅甸的主要是无人区的地段，这些地段有着世界上极端困难的地理环境，如热带雨林、急流、阶面和峡谷、布满丛林的山脉和多沼泽的河谷。
In spite of the enormous improvements in foundry technology , assisted by computerized processes to optimize the design of patterns and flow geometry during pouring it is extremely difficults to achieve x - ray / mt or pt quality to class 1 or 2 acceptance standards required in hp / ht applications in nuclear , thermal power stations or severe services in petrochemical industries 尽管铸造技术已经有了巨大的发展，并利用计算机技术辅助优化结构设计和浇铸过程的流体几何设计，但是要达到1类或2类接受标准的x射线/ mt或pt质量要求仍然是极端困难的，而这些都是核电站、热电站或石化工业内的苛刻环境所要求的标准。
