This paper describes a preliminary experimentation study on some effect of stress caused by exterior pressure in magnetic core upon phase-shifting characteristics of a ferrite phase shifter.
对磁芯因受外部压力产生应力时对铁氧体移相器移相特性影响进行了初步实验研究。
2
The preliminary practices show that underbalanced pressure drilling is completely fit to high pressure and low permeability as well as low pressure and leakage formations.
初步实践表明，负压钻井技术完全适用于高压低渗地层和低压易漏地层，其效果明显。
3
A preliminary study of the operation of the ammonia plant and the performance of the control with sliding pressure shows that the use of the control with sliding pressure is feasible and rational.