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Xiaozhe Chen,Junqi Liu,Jiaqi Zhang,Baitong Zhou 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4
This study investigates the frequency capture characteristic of four unbalanced rotors in multi-frequency ranges. First, using the average method, the synchronous condition of four unbalanced rotors in a vibration system is derived. Then, the stability condition of the vibration system is deduced, which meets the Routh-Hurwitz criterion. On the basis of the theoretical analysis, the phase difference in steady states and the resultant force on the rigid body at different excitation frequency regions are discussed numerically. Five sets of experiments are done to investigate synchronization and the Sommerfeld effect. The results prove that the vibration system has three motion states according to the excitation frequency in different frequency regions. Two stable states appear in the near-resonance region of the system. This study concludes that the synchronization of unbalanced rotors formed before and after the natural frequency is crucial for the occurrence of the Sommerfeld effect. This work can provide theoretical and experimental reference for the design of new vibration equipment in engineering.
Xiaozhe Wang,Xiaofeng Ren,Jie Yang,Zican Zhao,Xiaoyu Zhang,Fan Yang,Zheye Zhang,Peng Chen,Liping Li,Ruiping Zhang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00
Rationale To realize imaging-guided multi-modality cancer therapy with minimal side effects remains highly challenging. Methods We devised a bioinspired hollow nitrogen-doped carbon sphere anchored with individually dispersed Mn atoms (Mn/N-HCN) via oxidation polymerization with triton micelle as a soft template, followed by carbonization and annealing. Enzyme kinetic analysis and optical properties were performed to evaluate the imaging-guided photothermally synergized nanocatalytic therapy. Results Simultaneously mimicking several natural enzymes, namely peroxidase (POD), catalase (CAT), oxidase (OXD), and glutathione peroxidase (GPx), this nano-multizyme is able to produce highly cytotoxic hydroxyl radical (•OH) and singlet oxygen (1O2) without external energy input through parallel and series catalytic reactions and suppress the upregulated antioxidant (glutathione) in tumor. Furthermore, NIR-II absorbing Mn/N-HCN permits photothermal therapy (PTT), enhancement of CAT activity, and photoacoustic (PA) imaging to monitor the accumulation kinetics of the nanozyme and catalytic process in situ. Both in vitro and in vivo experiments demonstrate that near-infrared- II (NIR-II) PA-imaging guided, photothermally enhanced and synergized nanocatalytic therapy is efficient to induce apoptosis of cancerous cells and eradicate tumor tissue. Conclusions This study not only demonstrates a new method for effective cancer diagnosis and therapy but also provides new insights into designing multi-functional nanozymes.