Superhydrophobic fiber membranes have become a hotspot of research in the field of functional surfaces due to their unique surface properties. Electrospinning as an emerging technique is simple to operate, and can effectively modulate the surface morphology of nanofibers and realize micro/nano double structure selfassembly. Thus, superhydrophobic micro/nano fiber surface materials are obtained. The surface morphology and physical properties of the micro/nano fibers prepared by this technique are close to those of natural fiber superhydrophobic materials. This article first introduces the selfcleaning theorectical basis of superhydrophobic surface materials and the technical principle of electrospinning in brief, and then focused on the latest research progress of electrospinning technology to prepare superhydrophobic surface materials.

 

Rotor system is an important device in petrochemical equipment units and there is a non-normal phenomena of big vibration in it. Based on the finite element method, the model of the dynamics characteristics of a rotor system was set up, and problems such as critical speeds and steady imbalance response were calculated. The effect of imbalance distribution on rotor dynamics characteristics was studied and the parameters affecting the dynamics characteristics of the rotor system were found out. This provides a theoretical basis for fault diagnosis and resolution of rotor system.

Aiming at the lack of the studies of valve train system of diesel engine, an accurate four-mass dynamics model was established based on traditional single mass dynamics model. The gearing chain was separated from dynamics model and simplified to four independent centralized masses. The dynamics characteristics of the valve train system were calculated directly by numerical simulation. And it is indicated that the four-mass dynamics model has its own correctness and superiorities compared with single mass dynamics model.