Numerical Analysis and Experimental Study of Symmetric Stepped Magnetic Fluid Seal with Three Magnetic Sources

Fuxiang Hao,Anle Mu 한국자기학회 2023 Journal of Magnetics Vol.28 No.2

A symmetric stepped magnetic fluid seal (SSMFS) structure with three magnetic sources is designed with the goal of improving the leakage problem under the large clearance rotary seal condition. The magnetic field distribution in the sealing clearance is analyzed using the finite element method when the radial and axial clearances are both 0.4 mm. The pressure capacity is calculated, and the effects of the height of permanent magnets, the length of the pole teeth, and the number of pole teeth are compared with those of diverging stepped magnetic fluid seal (DSMFS) and converging stepped magnetic fluid seal (CSMFS) with three magnetic sources. The numerical outcomes demonstrate that the SSMFS with three magnetic sources has a greater pressure capacity than the other two seal structures. The effects of magnetic fluid injection volumes, radial and axial clearances, various rotational speeds, and holding times are then investigated in tests to determine the pressure capacity of the SSMFS with three magnetic sources. The results are compared to those of the other two structures. The experimental date indicate that the SSMFS with three magnetic sources has a magnetic fluid injection saturation of around 7 ml. The advantages of the SSMFS structure become more clear with the modification of the radial clearance and axial clearance. With an increase in rotation speed and holding time, the pressure capacity of SSMFS with three magnetic sources has no obvious change, but it is obviously higher than that of the other two structures.

Adaptive Back-stepping Neural Control for an Embedded and Tiltable Vtail Morphing Aircraft

Fuxiang Qiao,Jingping Shi,Xiaobo Qu,Yongxi Lyu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.2

This paper presents an adaptive back-stepping neural control (ABNC) method for the coupled nonlinear model of a novel type of embedded surface morphing aircraft. Based on a large number of aerodynamic data for different V-tail configurations, the longitudinal and lateral aerodynamic characteristics of the aircraft are analyzed, and a nonlinear model with six degrees-of-freedom is established. To avoid the problem of “differential explosion,” the controller is designed using the traditional back-stepping control (TBC) method with a first-order filter. Radial basis function neural networks are introduced to estimate the uncertainty and external disturbance of the model, and a controller based on the ABNC method is designed. The stability of the proposed ABNC controller is proved using Lyapunov theory, and it is shown that the tracking error of the closed-loop system converges uniformly within specified bounds. Simulation results show that the ABNC controller works well, with better tracking performance and robustness than the TBC controller.

Finite Element Analysis and Experimental Study on Magnetorheological Fluid Seal of the Hydraulic Cylinder

Fuxiang Hao,Anle Mu 한국자기학회 2022 Journal of Magnetics Vol.27 No.3

In order to solve the leakage problem of the engineering mechanical hydraulic cylinder, a magnetorheological fluid (MRF) seal structure with a multistage source is designed. The magnetic f ield in the gap of the sealing structure is analyzed by ANSYS finite element analysis method, the influence about the number of magnetic sources and the length of pole teeth on the pressure capability of the MRF seal is studied, and the results are analyzed. The results show that the suitable number of magnetic sources is 10; The length of the pole teeth with the best magnetic concentrating effect is 0.7 mm. Then, the influence of the MRF injection volume, reciprocating speed, reciprocating distance and holding pressure time of the hydraulic cylinder on the MRF sealing pressure capability is studied. The experimental results show that the maximum pressure capacity can be achieved when the MRF injection volume is 12 ml. With the increase of reciprocating speed, the pressure capability of the MRF seal decreases obviously. With the increase of reciprocating distance and holding time, the sealing pressure capability has no obvious change. Through the finite element analysis and experimental study of the MRF seal, it is of great significance to develop a device with high sealing performance suitable for the hydraulic cylinders.

Reflections on Weiwo Concept of Pre-Qin Daoism and on Individualism in Chinese Traditional Culture

( Zhang Fuxiang ) 성균관대학교 유교문화연구소 2009 儒敎文化硏究(中文版) Vol.0 No.12

現代西方學者所界定的個人主義, 强調以“自我”爲中心, 很容易使人想到中國先秦道家的“爲我”主張。 中國先秦道家的“爲我”主張, 以楊朱爲代表人物, 號稱“不拔一毛利天下”, 以爲“人人不損一毫, 人人不利天下”則“天下治”。這一主張基于道家“全性葆眞, 不以物累形”的人生哲學, 其中包涵了對生命的重視、“自我”存在价値的肯定及人人生來平等的觀念。而在先秦學者的政治言論中, 專從人性論及人生觀的立場出發, 以個人爲社會治理的起点, 這也是最明確的表述。其核心觀念很接近《簡明不列顚百科全書》所說:“個人本身就是目的, 具有最高价値, 社會只是達到個人目的的手段。 ”道家“爲我”主張的政治含義指向“无爲而治”。“无爲而治”的理想狀態, 有如《老子》所描述的“小國寡民”式的古朴社會景象, 還帶有浓厚的自然主義色彩。其政治理念實際偏主于一種“自生自發的秩序”, 或說是原始性的“无政府主義”。楊朱所提供的治世模型, 把這種“自生自發的秩序”具體化了, 突出了風俗制度形成過程中的個人主義因素, 因而强調社會治理以個體(個人或家庭)爲本位, 人人爲自我也就是自我爲人人, 個體自治則群體亦治。所謂“人人不損一毫, 人人不利天下”, 引伸開來, 也就可以理解爲“任何人或集團都无權決定另外一個人的情形應該怎樣”。這樣的個人主義主張是建立在中國古代分散經營而力求自給自足的小農經濟基礎上的, 幷且明顯包含了對當下社會風俗制度的批判和否定, 幷不能簡單地指斥爲利己主義, 然與歷代儒家大力倡導的集體主義精神直接相沖突。 在中國學術史上, 楊朱“爲我”的理論表述不過昙花一現, 因爲它不适于中國傳統文化的土壤。中國傳統文化培植起來的是根深蒂固的集體主義, 作爲一種政治和社會哲學的個人主義, 在歷代占統治地位的思想中幾乎沒有存在的余地。中國傳統文化的重大特征之一是宗法制度從未中斷過, 而與宗法集體主義幷行的是道德至上主義(或說是泛道德化的傾向)。集體主義和個人主義都屬于歷史的范疇, 二者都離不開道德評价, 而在中國傳統文化的特定語境中, 二者的關系集中而普遍地體現爲公私之分、義利之辨。中國文化的現代轉型, 一方面是個人權利意識的强化與個人權益保障制度的改善;另一方面, 提倡道德自律、服務責任、大局觀念、整體精神, 幷因此而反對形形色色與自私自利相聯系的個人主義(特別是傳統宗法式的“家族主義”), 仍將是長期而必要的擧措。 Individualism defined by modern western scholars lays stress on egoism, which naturally reminds people of Weiwo concept of pre-Qin Daoism. Weiwo concept of Chinese pre-Qin Daoism is represented by Yang Zhu, who holds that being stingy is favorable for the nation. He states that if everyone is unwilling to lose a penny and merely concerned about his own profits, then the state can be peacefully ruled. This concept is based on the Daoist’s life philosophy of keeping one’s true nature and doing no harm to one’s health for the material things, which embodies the concepts of valuing life, approving egoism and asserting everyone is born equal. Among the political theories of pre-Qin scholars, this is the most definite statement which expresses from the standpoint of the theory of human nature and view of life that individual is the basis of governing a state. The core concept of it is quite similar to what is written in Britannica Concise Encyclopedia: “Individual itself is the end, and of the highest value. Society is only a means to an end.” The political connotation of the Weiwo concept of Daoism is directly pointed to Lao Zi’s idea of governing by doing nothing that is against nature. This ideal state, as described in Laozi (the book), is a simple sight of “small territory and population” and bears the impression of naturalism. The political idea of it puts emphasis on a spontaneous order, or a primary anarchism. By proposing the governing type, making this spontaneous order more specific and stressing the individual factor during the forming process of customs, Yang Zhu emphasizes that individual (or family) is the basis of governing a society, that one for oneself means one individual for all, and that individual self-governing leads to collective governing. The so-called idea of “everyone is unwilling to lose a penny and merely concerned about his own profits” can be more explicated that anyone or any group has no right to determine what another should be like. Such concept is based on the small-scale peasant economy, which is of decentralized management, but trying to be self-sufficient. It contains evident criticism and negation of the social customs at that time. So, it cannot be simply criticized as egoism, and yet it is directly contradictory to the collectivism advocated by Confucians. In the Chinese academic history, Yang Zhu’s Weiwo concept is only a nine day’s wonder since it doesn’t agree with the Chinese traditional culture. Collectivism is deeply planted and rooted in Chinese traditional culture. Individualism, a political and social philosophy, has no place in the dominating thoughts of the past dynasties. Patriarchal clan system is one of the most important characteristics of Chinese traditional culture. The concept of “Morality foremost” (or pan-moralizing tendency) is the idea that keeps abreast with patriarchal clan collectivism all the time. Collectivism and individualism fall into historical category and both are closely related to moral evaluation. In the specific context of Chinese traditional culture, the relationship between collectivism and individualism is embodied in “publicity and privacy” and “righteousness and profits”. The modern transformation of Chinese culture is, on the one hand, the strengthening of the awareness of individual rights and the improvement of individual rights and benefits protection; on the other hand, it is also reflected in the advocation of moral self-discipline, service duty, overall consciousness and associative spirit. Therefore, it is still a long-term and necessary task to combat various egoism in the form of selfishness, particularly the traditional patriarchal familism. [Article in Chinese]

Comparison of different mechanical fibrillation methods of HCW-treated bamboo fiber on enzymatic saccharification

이승환,( Fuxiang Chang ),김남훈,仄프置 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.0

Purple Sweet Potato (Ipomoea batatas L.) Color Alleviates High-fat-diet-induced Obesity in SD Rat by Mediating Leptin’s Effect and Attenuating Oxidative Stress

Yi Zhang,FuXiang Niu,Jian Sun,Fei Xu,RuiXue Yue 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.4

Obesity and associated diseases are world-wide problems. The preventive effect of purple sweet potato color (PSPC) on high fat diet (HFD) induced obesity was investigated along with the mechanism underlying the effect. Eight-week-old male Sprague Dawley strain rats were grouped into 7 groups and intragastrically administered PSPC once a day. Obesity was prevented and abnormal glucose, triglyceride, and total cholesterol levels induced by the HFD for 6 weeks were restored to near-normal levels. PSPC significantly (p<0.05) reduced the level of reactive oxygen species and inhibited the receptor of advanced glycation end products and thioredoxin interacting protein in the hypothalamus, compared with controls. PSPC preserved the leptin signaling capability, leading to a decrease in hypothalamic adenosine 5'-monophosphate activated protein kinase activity. The anti-obesity effects of PSPC were mediated via attenuation of oxidative stress and regulation of leptin/AMPK signaling in the hypothalamus.

Fault-Tolerant Control Based on Modified eXogenous Kalman Filter for PMSM

Ma Liling,Wang Fuxiang,Shen Wei,Wang Junzheng 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

Aiming at the encoder fault of the three-phase permanent magnet synchronous motor control system, a modified eXogenous Kalman Filter (MXKF) is proposed. When there are errors in the initial state of the estimator, MXKF performs well while extended Kalman Filter leads to an unstable state of the system. For the system under the Three-phase Four-switch drive, MXKF is shown to have better fault-tolerant stability. In addition, to avoid the unexpected equilibrium points determined by the q-axis voltage equation, proper compensation is made in the filter. Finally, simulations have been done to verify the effectiveness of the proposed method in the following two cases: start-up with initial error and topology change of the drive. The results show the satisfying superiority of MXKF.

A Chinese Restaurant Game for Distributed Cooperative Caching in Small Cell Networks

( Junliang Chen ),( Gang Wang ),( Fuxiang Wang ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.1

Wireless content caching in small cell networks has recently been considered as a promising way to alleviate the congestion of the backhaul in emerging heterogenous cellular network. However, how to select files which are cached in SBSs and how to make SBSs work together is an important issue for cooperative cache research for the propose of reducing file download time. In this paper, a Cooperative-Greedy strategy (CGS) among cache-enabled small base stations (SBSs) in small cell network is proposed, in order to minimize the download time of files. This problem is formulated as a Chinese restaurant game.Using this game model, we can configure file caching schemes based on file popularity and the spectrum resources allocated to several adjacent SBSs. Both the existence and uniquencess of a Nash equilibrium are proved. In the theoretical analysis section, SBSs cooperate with each other in order to cache popular files as many as possible near UEs. Simulation results show that the CGS scheme outperforms other schemes in terms of the file-download time.

Opto-mechanical Design of Monocrystalline Silicon Mirror for a Reflective Imaging Optical System

Xiaofeng Liu,Xin Zhang,Fuxiang Tian 한국광학회 2022 Current Optics and Photonics Vol.6 No.3

Monocrystalline silicon has excellent properties, but it is difficult to design and manufacture siliconbased mirrors that can meet engineering applications because of its hard and brittle properties. This paper used monocrystalline silicon as the main mirror material in an imaging system to carry out a feasibility study. The lightweight design of the mirror is completed by the method of center support and edge cutting. The support structure of the mirror was designed to meet the conditions of wide temperature applications. Isight software was used to optimize the feasibility sample, and the optimized results are that the root mean square error of the mirror surface is 3.6 nm, the rigid body displacement of the mirroris 2.1 μm, and the angular displacement is 2.5″ under the conditions of a temperature of Δ20 ℃ and agravity load of 1 g. The optimized result show that the silicon-based mirror developed in this paper can meet the requirements of engineering applications. This research on silicon-based mirrors can provide guidance for the application of other silicon-based mirrors.

One-Step Hydrothermal Synthesis of CoNi2S4 for Hybrid Supercapacitor Electrodes

Peng Liu,Yanwei Sui,Fuxiang Wei,Jiqiu Qi,Qingkun Meng,Yaojian Ren,Yezeng He 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.7

In this study, a simple one-step hydrothermal method was developed to prepare a novel hierarchical CoNi2S4 nanostructure similar to rambutan fruit. The surface microstructural study clearly visualized that the rambutan-like CoNi2S4 consists of nanorods grown directly on the surface of spherical core structures. The close attachment of the nanorods to the spheres increased the active areas of the electrode, which facilitates efficient charge transport from the nanorods to the spherical core structure. CoNi2S4 with a rambutan-like hierarchical structure showed an excellent specific capacitance of 944 F g -1 at 1 A g -1, considerable rate capacitance (75.6% retention at 10 Ag -1) and excellent cycling life (91.1% retention after 5000 circulations) in the three-electrode system. Besides, the assembled hybrid supercapacitor based on CoNi2S4 and reduced graphene oxide exhibited a high specific energy density of 23.58 Wh kg -1 at the power density of 800 W kg -1.