Coal resources; Mining rights; Convenience yield; Two-factor model.

煤炭资源；采矿权；便利收益；双因素模型。

However, the direct process, cracking method and hydrogenation of chlorosilanes were valuable because of less cost, high yield and convenience of continuous manufacturing.

而直接法、裂解法和还原法因其成本低廉，产率高，便于连续化生产，具有工业实用价值。

The merit of the approach lies in convenience, high yield rate, satisfactory isolating effect, and the method is well suited to chemistry experiment teaching.

该方法的优点在于简便易行，得率较高，分离效果好，适合用于化学实验教学中。