超声电磁复合场对AZ31B镁合金铸轧板带组织性能的影响

利用水平式双辊铸轧机进行了AZ31B镁合金超声波电磁复合场板带的铸轧试验,成功试制出了厚3mm、宽200mm的AZ31B镁合金铸轧板,研究了超声波电磁复合场对铸轧镁合金板带金相组织性能的影响。结果表明,在AZ31B镁合金铸轧过程中施加超声波电磁复合场能够使晶粒细化,组织更加均匀,平均晶粒尺寸由不加超声波电磁复合场时的30～60μm减小至10～20μm;板带坯力学性能也得到有效改善,抗拉强度、屈服强度和延伸率分别提高了23.6%、43.2%、107.2%,硬度提高了10%。在此基础上探讨了超声波空化效应及电磁效应对铸轧镁合金板带组织细化的作用机制。

油田智能变频电磁防蜡装置应用及评价

为了解决油田油井清蜡降黏等问题,减少热洗井频率,缩短检泵周期,达到节能降耗的目的,开展了丰5-12井、袁1-26井的智能变频电磁防蜡装置试验。智能变频电磁防蜡装置是一种利用磁场和声波组合空化效应的防蜡装置,该装置采用微电脑控制,扫频磁场、声波,温度受控功率可调整。通过试验,该装置结构简单,安装方便,用电少,耗能低,可以延长油井热洗周期,有效减少加药费用。据统计,2口井节电率达到60%,年节约费用29万元,取得了较好的节能效果。

Three-Dimensional Dust-Acoustic Waves in a Collisional Dusty Plasma with Opposite Polarity Particles

The dispersion relation is derived for three-dimensional dust-acoustic waves in a current-driven dusty plasmas with both positively and negatively charged dust particles. The dependencies of the frequency and the growth rate on the wave number K, the intensity of magnetic field B, and the inclination angle θ have been numerically shown in this paper. The growth rate is negative for the laboratory dusty plasma, but it is positive for the cosmic dusty plasma. It is found that when the inclination angle θ = π/2, there is no instability. The effect of the electrostatic field Eo has also been studied in this paper.