However, NC devices have high prices and there’re some volatile factors when NC system is under the practical operation, which incumber the testing and operation process.

但数控设本较，同时数控系统在实际运转过程中存在一些不稳定因素，运行调试工作带来不便。

Further more, the technical efficiency was suppressed by the advantage of resources in this area, strategy of exploring resources incumber the economy in the long run.

分析表明，源优势妨碍了技术效率，源开发战略不利于经济长期增长。