A top-face-sway electromagnetic micromotor

In this paper, the structure of a top-face-sway electromagnetic micromotor and its principle, fabrication and performance are introduced. A combination of the electromagnetic actuating and the planetary reducing provides this micromotor an advantage of low rotational speed and high torque. In addition, since a flexible coupling absorbs the sway and only outputs rotation, it gives this micromotor a balanced output. The dimension of the micromotor is 5 mm. Its rotation speed has a range of 20 - 860 rpm, and its driving current is 300 mA. The output torque of the micromotor is measured to be 13.0 uNm.     

岩石射孔开裂的初步数值模拟

岩石射孔作业后孔眼周围裂缝分布规律对后续压裂有不可忽视的影响。选取射孔围岩的横切面为研究对象，将三维射孔侵彻过程简化为二维扩孔过程。考虑岩石细观非均匀性，设细观强度参数服从韦布尔分布。应用拉伸破坏准则和Mohr-Coulomb压剪破坏准则，并用模量折减法处理单元开裂，从而用FEPG软件实现了有限元数值模拟。模拟结果表明:射孔后的岩石可根据裂缝产生原因及分布由内而外划分为四个区域:压剪破坏区、拉伸破坏集中区、拉伸破坏扩展区和未破坏区。分析了不同射孔弹规格及围压条件下裂纹分布变化规律。与室内模拟实验结果进行对比分析，初步验证了模型的有效性。     

A top-face-swav electromagnetic micromotor

In this paper, the structure of a top-face-sway electromagnetic micromotor and its principle, fabrication andperformance are introduced. A combination of the electromagnetic actuating and the planetary reducingprovides this micromotor an advantage of low rotational speed and high torque. In addition, since a flexiblecoupling absorbs the sway and only outputs rotation, it gives this micromotor a balanced output. Thedimension of the micromotor is 5 mm. Its rotation speed has a range of 20 - 860 rpm, and its drivingcurrent is 300 mA. The output torque of the micromotor is measured to be 13.0 μNm.     

高能X射线组合透镜聚焦性能的实验结果

高能X射线组合透镜是一种基于折射效应的新型X射线光学元件。报道了这种新型X射线光学元件聚焦性能的最新实验结果。设计的高能X射线组合透镜为聚甲基丙烯酸甲酯(PMMA)材料,包括40个相同的、顺序排布的平凹折射单元,折射单元的球面半径为200μm,组合透镜的几何口径约为500μm,长度约为8 mm,焦距约为1.3 m。简要描述了PMMA材料X射线组合透镜的制作技术和制作过程。并给出了X射线组合透镜聚焦性能测试实验系统和实验条件。最后给出8 keV单色X射线辐射下,PMMA材料X射线组合透镜的聚焦性能的测试结果,对实际测试结果进行了分析和讨论,得出结论,焦距等参量与理论计算结果基本吻合。