同素异形的

A soft, steel-gray to black, hexagonally crystallized allotrope of carbon with a metallic luster and a greasy feel, used in lead pencils, lubricants, paints, and coatings, that is fabricated into a variety of forms such as molds, bricks, electrodes, crucibles, and rocket nozzles.

石墨：一种质软、钢灰黑色、有金属光泽和滑腻感的碳的六方晶形的同素异构体，用于铅笔、滑润剂、颜料和涂层，可被制成多种形状，如模子、砖块、电极、坩埚和火箭发动机喷管也作 black lead ， plumbago

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。