压顶石

This topic is designed to protect the oil pipe thread spinning apparatus for equipment design, In the design process, the teacher asked us to use the knowledge to complete electro-hydraulic design features include spinning machine tool design、 The top end of the design, spinning mechanical design, hydraulic control system design, the design of the transmission system, electrical system and the PLC design.

本次设计题目是石油管螺纹保护帽旋压专用设备设计，在设计过程中，老师要求我们运用机电液的知识完成，设计的内容主要包括，旋压机床总体设计、尾顶的设计、旋压机构设计、液压控制系统设计、主传动系统的设计、电气系统及PLC的设计。

The fore bay of Heihe Longhui Hydropower Station designed by the company, is the existing biggest tunnel fore bay in China, which is height of 21m, width of 16m; for the large-span dome of surge tank of Baishuijiang Shiji Hydropower Station, which is the first project equipped with rapid-drop gate in surge tank in Gansu Province, the company adopted pre-stressed anchor cable to complete the dome's excavation and supporting at the same time, thus reduced the completion period and investment; for the diversion tunnel of Fuchuan Hydropower Station, which is the biggest non-pressure diversion tunnel in Gansu Province, with span of 9m, height of 11m, the company adopted half-tunnel supporting structure, thus reduced the project investment.

黑河龙汇水电站前池是目前国内最大的洞内式前池，跨度16m、高度21m；白水江石鸡水电站调压井大跨度穹顶采用预应力锚索技术，分瓣开挖一次支护完成，节省了工期和造价，同时是省内第一座在调压井内设置快速闸门的工程；福川水电站引水隧洞是甘肃省内最大的无压引水隧洞，跨度9.0m，高度11m，采用半洞支护结构，在满足安全的前提下节省了工程投资。

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。