The PDM′s conventional bushing is a screw surface,it is a variable-thickness elastomer stator.
目前,常规螺杆钻具衬套的内表面是螺旋曲面,橡胶衬套厚薄不均,衬套抗变形能力低,单级承压小,泄漏沿程长,机械特性软,热膨胀不均、磨损速度快,故导致效率持续降低。
The effects of biodiesel and diesel on mass, dimension and appearance of elastomers, metals and plastics are comparatively investigated after 28-day immersion.
研究了多种橡胶、金属和塑料在3种生物柴油中浸泡28天后的质量、尺寸及外观变化,并与0号柴油的结果进行对比。
Study of Blue Stain Fungi in Hevea brasiliensis and Pinus marssoniana Wood as well as the characteris tics of Ceratocystis sensu lato in the fungi;
橡胶、松树木材变色菌研究及对其中之长喙壳属菌的特性研究