Magnetic bearings have a series of excellent qualities, such as no friction and abrasions, high speed, high accuracy, and so on, which have fundamentally innovated traditional forms of support. In order to solve the problems of the large volume, low power density and high coupling coefficient of three-pole magnetic bearings, a six-pole AC active magnetic bearing is designed. Firstly, the basic structure and working principle of a two-degree-of-freedom (2-DOF) six-pole active magnetic bearing is introduced. Secondly, a suspension force modeling method of a 2-DOF AC active magnetic bearing based on the Maxwell tensor method is proposed, and the mathematical model of active magnetic bearing is established. Considering the fact that AC active magnetic bearing is essentially a nonlinear system, a fuzzy active disturbance rejection control (ADRC) method is designed based on fuzzy control and ADRC theory. Its control algorithm and control block diagram are given, and the fuzzy ADRC method is simulated and verified. Finally, the control block diagram of an experimental system based on the 2-DOF six-pole active magnetic bearing is given, and the experimental platform is constructed. The experimental results show that the mechanical and magnetic circuit structure of the 2-DOF six-pole active magnetic bearing is reasonable, and the fuzzy controllers can realize the stable suspension of the rotor.

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As a progressive neurodegenerative disease, Alzheimer's disease (AD) is characterized by the accumulation and misfolding of amyloid polypeptides (Aβ) which result in irreversible brain damages, cognitive decline and behavioral impairment. Photodynamic therapy (PDT) has received much attention as a potential approach for AD treatment. In this study, we investigated a novel multifunctional theranostic photosensitizer, copper cysteine (Cu-Cy). By performing PEG modification on nanoparticles’ surface, the particle size and cytotoxicity were significantly reduced. Under UV irradiation, Cu-Cy-PEG can produce reactive oxygen species (ROS) and could degrade Aβ(1-40) aggregates efficiently. This is the first case for Cu-Cy-PEG being used for degrading Aβ aggregates in vitro. The macroscopic amyloid aggregates were photodegraded by Cu-Cy-PEG into amorphous particles. This study firstly proved that Cu-Cy-PEG may serve as a potential treatment in AD therapy.