Material and Methods: Hysteroscopy was performed in 48 patients with remained intrauterine device, embryo and placenta after failure of a general uterine curettage and remove of intrauterine divice.

To improve efficiency and veracity of soil sampling in testing bulk density, the cutting ring method and in situ soil tube method were combined and a multi-segment in situ soil sampler was designed.

This paper introduced the basic principle of air vortex spinning and laid stresses on curl flow field in the air vortex twister, and the collecting and taking off of link fiber in air vortex spinning.