包层金属的

An electric strength test in accordance with 29.3.2, if the insulation consists of more thanone separate layer, other than natural mica or similar flakey material, or by

按29.3.3通过的材料做21.2是不难理解的， 29.3.2中如果遇到带电金属体外包三层绝缘胶带作加强绝缘，胶带是不是容易通过穿刺测试呢？

Protection from corrosion: before goods are packed, materials which are liable to deterioration during transit should be properly treated with protective;highly polished metal surface are particularly subject to the dangers of rust and corrosion;It is customary to coat the surfaces thickly with a slushing oil; anti-corrosive compounds, films, wax or grease should be applied.

防腐蚀包装：在货物包装之前，对在运输过程中可能变质的材料采取适当的防护处理；抛光的金属表面很容易生锈和腐蚀。通常在表面刷上一层厚厚的抗腐蚀润滑油；防腐化合剂、薄膜、蜡、润滑油等是必用之物。用刷子、喷漆枪涂上，或在浸泡桶里加以处理；密封的容器和除湿化合物，如可用硅脂胶体；大体积液体通常装在鼓形圆桶或罐里；一些材料应该用防水纸或石蜡包纸；为了预防高危险材料，船运公司规定了包装规格；箱子应该与防水纸和布一致。

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。