Silicon for integrated circuits requires high purity, diameter and impurity content of silicon materials, and China's vigorous development of the semiconductor industry, there is a great demand for raw materials, but their own silicon materials can not be broken through in a short time, only in 2017 China's total imports of integrated circuits reached 1.76 trillion yuan.
Aircraft engines are firmly controlled by the United States Pratt & Whitney, General Electric, the United Kingdom Rollo, and CMF 4, occupying 97% of the global market share.
Ships using diesel engines are basically MAN B&W diesel engine company and W?rtsil? company monopoly. China's development in this area is lagging behind, there are still large gaps with foreign countries, so the main imports.