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Sensitive parameters’ optimization of the permanent magnet supporting mechanism
Yongguang Liu,Xiaohui Gao,Yixuan Wang,Xiaowei Yang 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.7
The fast development of the ultra-high speed vertical rotor promotes the study and exploration for the supporting mechanism. It hasbecome the focus of research that how to improve the speed and overcome the vibration when the rotors pass through the low-order criticalfrequencies. This paper introduces a kind of permanent magnet (PM) supporting mechanism and describes an optimization method ofits sensitive parameters, which can make the vertical rotor system reach 80000 r/min smoothly. Firstly we find the sensitive parametersthrough analyzing the rotor’s features in the process of achieving high-speed, then, study these sensitive parameters and summarize theregularities with the method of combining the experiment and the finite element method (FEM), at last, achieve the optimization methodof these parameters. That will not only get a stable effect of raising speed and shorten the debugging time greatly, but also promote theextensive application of the PM supporting mechanism in the ultra-high speed vertical rotors.
A Monitoring Algorithm Based on IP Address Statistics in DCS Isolation Device
Yongguang MA,Zhiyu YE 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.5
Distributed Control System (DCS) requires communication with external system, which probably causes the invasion of the viruses and malicious programs, finally resulting in the fault of units. One-way physical isolation device is efficient to solve the current threat but not aware of the potential danger. In this paper, a monitoring algorithm is introduced to predict and detect the abnormal communication based of IP address statistics, thus increasing reliability and flexibility of the communication.
67-fs pulse generation from a mode-locked Tm,Ho:CLNGG laser at 2083 nm
Zhao, Yongguang,Wang, Yicheng,Chen, Weidong,Pan, Zhongben,Wang, Li,Dai, Xiaojun,Yuan, Hualei,Zhang, Yan,Cai, Huaqiang,Bae, Ji Eun,Choi, Sun Young,Rotermund, Fabian,Loiko, Pavel,Serres, Josep Maria,Mat The Optical Society 2019 Optics express Vol.27 No.3
Pressure Pulsation Characteristics of a Model Pump-turbine Operating in the S-shaped Region
Linsheng Xia,Yongguang Cheng,Fang Cai 한국유체기계학회 2017 International journal of fluid machinery and syste Vol.10 No.3
The most detrimental pressure pulsations in high-head pump-turbines is caused by the rotor-stator interaction (RSI) between the guide vanes and runner blades. When the pump-turbine operates in the S-shaped region of the characteristic curves, the deteriorative flow structures may significantly strengthen RSI, causing larger pressure pulsations and stronger vibration with an increased risk of mechanical failure. CFD simulations were carried out to analyze the impacts of flow evolution on the pressure pulsations in the S-shaped region of a model pump-turbine. The results show that the reverse flow vortex structures (RFVS) at the runner inlet have regular development and transition patterns when discharge reduces from the best efficiency point (BEP). The RFVS first occur at the hub side, and then shift to the midspan near the no-load point, which cause the strongest pressure pulsations. The locally distributed RFVS at hub side enhance the local RSI and makes the pressure fluctuations at the corresponding sections stronger than those at the rest sections along the spanwise direction. Under the condition of RFVS at the mid-span, the smaller flow rate make the smaller difference of pressure pulsation amplitudes in the spanwise direction. Moreover, the rotating stall, rotating at 35.7%-62.5% of the runner rotational frequency, make the low frequency components of pressure pulsations distribute unevenly along the circumference in the vaneless space. However, it have little influence on the distributions of high components.
Xia, Linsheng,Cheng, Yongguang,Cai, Fang Korean Society for Fluid machinery 2017 International journal of fluid machinery and syste Vol.10 No.3
The most detrimental pressure pulsations in high-head pump-turbines is caused by the rotor-stator interaction (RSI) between the guide vanes and runner blades. When the pump-turbine operates in the S-shaped region of the characteristic curves, the deteriorative flow structures may significantly strengthen RSI, causing larger pressure pulsations and stronger vibration with an increased risk of mechanical failure. CFD simulations were carried out to analyze the impacts of flow evolution on the pressure pulsations in the S-shaped region of a model pump-turbine. The results show that the reverse flow vortex structures (RFVS) at the runner inlet have regular development and transition patterns when discharge reduces from the best efficiency point (BEP). The RFVS first occur at the hub side, and then shift to the mid-span near the no-load point, which cause the strongest pressure pulsations. The locally distributed RFVS at hub side enhance the local RSI and makes the pressure fluctuations at the corresponding sections stronger than those at the rest sections along the spanwise direction. Under the condition of RFVS at the mid-span, the smaller flow rate make the smaller difference of pressure pulsation amplitudes in the spanwise direction. Moreover, the rotating stall, rotating at 35.7%-62.5% of the runner rotational frequency, make the low frequency components of pressure pulsations distribute unevenly along the circumference in the vaneless space. However, it have little influence on the distributions of high components.
Weijin Gao,Liang Wang,Yongguang Liu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.11
We determined the actuator location based on the dynamic modal of gear shaft, and analyzed the feasibility of a modified filtered-x least mean square algorithm with online secondary path identification. The proposed adaptive controller is designed to drive the actuators for preventing the vibration caused by gear backlash from a gear pair passing to the external gear housing structure. For the vital identification system, a changed identification input with error energy is presented to reduce the impact of additive random noise on the whole system. To ensure a realistic assessment of the proposed control strategy, numerical studies were implemented for a gearbox used by NASA-GRC. The simulation results validate the efficiency of the proposed approach through promising vibration control results that will guide future experimental work.
78 fs SWCNT-SA mode-locked Tm:CLNGG disordered garnet crystal laser at 2017 nm
Wang, Yicheng,Zhao, Yongguang,Pan, Zhongben,Bae, Ji Eun,Choi, Sun Young,Rotermund, Fabian,Loiko, Pavel,Serres, Josep Maria,Mateos, Xavier,Yu, Haohai,Zhang, Huaijin,Mero, Mark,Griebner, Uwe,Petrov, Val The Optical Society 2018 Optics letters Vol.43 No.17
Qiao Ning,Liu Yongguang,Liu Jie,Zhang Dezhen,Chi Wenjuan,Li Jintang,Zhu Xiaoping,Liu Hongmei,Li Fajun 한국유전학회 2023 Genes & Genomics Vol.45 No.1
Background Tomato spot wilt virus (TSWV) and tomato yellow leaf curl virus (TYLCV) are highly harmful viruses in agricultural production, which can cause serious economic losses to crops and even devastating consequences for vegetable yield in some countries and regions. Although the two viruses belong to different families and have different transmission vectors, they share most hosts. Objective This study aimed to examine the transcriptomic expression of single and mixed inoculations of TSWV and TYLCV, leading to antagonism using high-throughput RNA sequencing. Methods We confirmed the single and mixed infections of these viruses in Nicotiana benthamiana (N. benthamiana) by artificial inoculation. And the expression changes of related genes and their biological functions and pathways during the mixed infection of TSWV and TYLCV were analyzed by comparative transcriptome. Results Basically, similar symptoms were observed in the plants singly infected with TSWV and co-infected with TYLCV; the symptoms of TYLCV in the co-infected plants were not obvious compared with single TYLCV infections. When inoculated with TYLCV, the accumulation of the virus significantly reduced in single and mixed infections with TSWV; the TSWV accumulated slightly less in co-infection with TYLCV, whereas this reduction was much smaller than that of TYLCV. The results suggested that TSWV had an antagonistic effect on the accumulation of TYLCV in N. benthamiana. It mainly focused on the changes in unique differentially expressed genes (DEGs) caused by the co-infection of TSWV and TYLCV. The eight pathways enriched by upregulated DEGs mainly included amino acid biosynthesis, citrate cycle (or tricarboxylic acid cycle, TCA cycle), and so on. However, only pentose phosphate pathway (PPP) and peptidoglycan biosynthesis could be downregulated in the Kyoto Encyclopedia of Genes and Genomes pathway in which peptidoglycan biosynthesis was involved in upregulated and downregulated pathways. Conclusions The antagonistic effect of TSWV on TYLCV in N.benthamiana and the change trends and specific pathways of DEGs in this process were found. Our study provided new insights into the host regulation and competition between viruses in response to TSWV and TYLCV mixed infection.
Xiao-Lin Yuan,Lipo Mo,Yongguang Yu,Guo-Jian Ren 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.7
This paper mainly considers the distributed containment control problem for continuous-time fractionalorder multi-agent systems (FOMASs) with double-integrator, where the control input of each agent is constrained to lie in a nonconvex set. A distributed projection containment control algorithm is designed for each follower. To finish the convergence analysis, the original closed-loop system is first changed into an equivalent one by a proper model transformation and the method of the L1 interpolation approximation is introduced to deal with the projection operator. Then, by using the properties of the convex hull and the Mittag-Leffler function, it is shown that the largest distance between the followers and the convex hull spanned by leaders tends to zero asymptotically, while all agents’ control inputs are constrained to stay in their corresponding nonconvex constraint sets. Finally, numerical simulations are provided to verify the effectiveness of the theoretical results.