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Xiufeng Liu,Wei Wei,JinChun Yuan,Yuxuan Tao,Yuheng Li,Yu Huang 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.11
For the ultra-precision turning machine, the spindle system is a core component and plays a decisive role in precise machining. The unbalancing state in the spindle can degrade the quality of the machining surface. Therefore, the spindle system must be exceptionally well balanced before processing. In this paper, we proposed a high accuracy spindle balance method, which adopts the real-time data in the CNC system and combines with disturbance observer (DOB) to estimate the unbalancing vector without any extra sensors. Moreover, this method takes full advantage of the ultra-precision machine structure, the high precision grating, and the high-performance motor servo system to achieve high accuracy measurement for the spindle unbalancing. According to the experimental results, the proposed method accuracy is up to G0.0073, which is at least three levels greater than the highest official ISO balancing quality grade G0.16. In the cutting experiments, the PV value reduce to 0.207 μm from 0.528 μm with upgrading the spindle balance grade to G0.01024 from G0.16, verifies the accuracy of the spindle dynamic balancing method from the practice side.
Zhiying Liu,Yulin Li,Xiaohui Sun,Zhuyin Sui,Xiufeng Xu 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.112 No.-
This study explored the feasibility of coupling N2O decomposition with ethylbenzene (EB) oxidativedehydrogenation, as an alternative approach for greenhouse gas elimination and styrene (ST) production,on the Co-Al mixed oxides and K-modified catalysts. It was found that N2O could decompose completelyover the K/Co2AlO4 catalyst, accompanied with 62.0% of EB conversion and 85.1% of styrene selectivity,which were much better than the existing catalyst systems for EB oxidative dehydrogenation. Characterization results showed that despite the decreased specific surface area of the catalysts withincreasing the Co/Al molar ratio, the improved reducibility, the reduced acid properties as well as thehigher ratio of Co3+/Co2+ were responsible for the enhanced performance. The K modification not onlychanged the electronic properties of active metal, resulting from the charge transfer from K cation tothe Co species, but also weakened the binding energy of Co3+-O, leading to the complete decompositionof N2O. Furthermore, the optimized strong acid properties inhibited the dealkylation or ring-openingreactions and significantly reduced the coke deposition on the catalyst surface, thus improving the STselectivity.
Synchronization of Kuramoto-oscillator networks based on cyber-physical system
Guo Xiufeng,Rao Pengchun,Liu Min 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.82 No.2
Based on the framework of cyber-physical system (CPS), this investigation discusses the frequency synchronization and bounded synchronization, respectively, of the Kuramoto network with non-identical oscillators, in which the initial phases are dispersed over a semicircle. Firstly, the sufficient condition for guaranteeing phase-trapping is deduced. Then, the sufficient criteria for achieving frequency synchronization is further obtained, and a lower bound for synchronization rate is established. Secondly, the sufficient condition for ensuring bounded synchronization is derived, which can restrict the phase difference within an arbitrary pre-given bound ε in finite time. Finally, numerical examples validate the effectiveness and feasibility of the derived analytical results.
Threshold magnetoresistance in anistropic magnetic 2D transition metal dichalcogenides
Xu, Hongjun,Hsu, Ming-Chien,Fuh, Huei-Ru,Feng, Jiafeng,Han, Xiufeng,Zhao, Yanfeng,Zhang, Duan,Wang, Xinming,Liu, Fang,Liu, Huajun,Cho, Jiung,Choi, Miri,Chun, Byong Sun,Ó,Coileá,in, Cormac The Royal Society of Chemistry 2018 Journal of Materials Chemistry C Vol.6 No.12
<P>Recently many novel magnetoresistance (MR) phenomena have been reported from studies of two dimensional (2D) materials. Here, we report on the exotic transport behavior of VS2. A large negative and quadratic MR of −10% is observed for an in-plane magnetic field B up to 14 T. Remarkably, when the applied field deviates from the in-plane orientation there is a threshold field, Bc, and the MR shows a plateau of near zero MR. When B < Bc, only a single state exists and the transition between quantum spin states is forbidden. Our work sheds new light on the MR of magnetic 2D materials with localized states and may spur further investigations.</P>