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Sensitivity analysis of rolling bearing fatigue life under cyclic loading
Xianming Wang,Qingling Meng,Tianxiao Zhang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.11
Rolling bearings are regularly subjected to cyclic loading, and the load changing sequence has a significant influence on bearing fatigue life. The study offers a cumulative fatigue damage theory based on the improved Lundberg-Palmgren method that takes into account the effect of load changing sequence on bearing fatigue life and then proposes a modified Miner bearing fatigue life model. Additionally, the state function for the bearing fatigue life analysis is developed based on the basic dynamic load rating and stress-strength interference model of the bearing. A moment-based sensitivity analysis method for bearing fatigue life is proposed for studying the influence of different variables on bearing fatigue life. Finally, a sensitivity analysis of the fatigue life of 6209 deep groove ball bearings was performed as an example. The calculation results demonstrate that the modified Miner life model is comprehensive and that the moment-based sensitivity analysis method is simple and accurate.
Tri-metal-based hollow nanorods-on-microrod arrays as efficient water splitting electrocatalysts
Jianzhi Wang,Hongliang Yu,Xianming Wang,Chen Chen,Shuaijie Li,Ning Cai,Weimin Chen,Yanan Xue,Hui Li,Faquan Yu 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-
Constructing ordered hierarchical porous electrocatalysts while maintaining their high efficiency and stabilityfor oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is highly desirable butstill remains challenging. Herein, hierarchical tri-metal-based hollow nano/micro rod-on-rod array structures,including hydroxides and phosphates, are vertically grown on Cu foam by the cation-exchangingand anion exchanging approaches. Such ordered porous architecture, providing multi metal center, regularinterconnection of macropore channel, large electrochemical surface area, small charge-transferresistance, efficient mass transport and electron transfer for overall water splitting in alkaline media. These obtained hydroxide OER catalysts (CoMn LDH@Cu(OH)2/CF) and phosphide HER catalysts(CoMnP@Cu3P/CF) exhibited low onset potential, low Tafel slope, and prominent durability. Such excellentperformance, ordered porous structure and simple preparation methods indicate that this study providesa new strategy for assembling promising catalysts for water splitting and other applications.
Synthesis and Curing of AUT-PNIMMO with Three Functional Groups
Xiaochuan Wang,Ping Li,Xianming Lu,Hongchang Mo,Minghui Xu,Ning Liu,Yuanjie Shu 한국고분자학회 2019 폴리머 Vol.43 No.4
T-PNIMMO with three functional groups was synthesized by cationic ring opening polymerization of NIMMO (3-nitratomethyl-3-methyloxetane) in the presence of TMP (trimethylolpropane) catalyzed by BF3·OEt2. Then AUTPNIMMO was synthesized by T-PNIMMO and allyl isocyanate. The polymers were characterized by FTIR, 1H NMR, 13C NMR, and their thermal stability was estimated by DSC. Moreover, tensile testing was used to evaluate the mechanical properties of polyurethane elastomer based on T-PNIMMO and toluene-2,4-diisocyanate (TDI), and isoxazoline elastomer based on AUT-PNIMMO and tetramethyl-terephthalobisnitrile oxide (TTNO). This showed an increase of tensile strength from 2.0 to 4.0 MPa and elongation at break from 150% to 500%, respectively. These results indicated that AUTPNIMMO exhibited a good thermal stability, had satisfactory mechanical properties and was expected to be used in the composite solid propellant and polymer bonded explosives.
New De-excitation Method for Large Hydraulic Generator
Chen, Xianming,Wang, Wei,Lu, Hongshui,Liu, Guohua,Zhu, Xiaodong The Korean Institute of Electrical Engineers 2011 The Journal of International Council on Electrical Vol.1 No.2
The requirement for arc voltage during the opening of a field breaker for large hydraulic generator increases when de-excitation (DE) is performed with a varistor parallel connected to field wingding. In fact, E.M.F of the field winding is required to be higher than the varistor threshold voltage during opening of field breaker. In this paper, the principle of DE with capacitors is introduced. The high voltage produced during DE by the R,L,C series oscillation is used to force the varistor into operation which decreases the opening arc voltage requirement of the field breaker. A simulation is completed to confirm the proper operation of the new DE approach.
Genetic homogeneity between populations of cotton bollworm from Xinjiang, China
Dongmei Wang,Xianming Yang,Haiqiang Li,Akedan Wuwaishi,Ruifeng Ding,Haobin Li,Hongsheng Pan,Jian Liu,Yao Xu,Yan-Hui Lu 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.1
We studied the population structure of cotton bollworm (CBW), Helicoverpa armigera (Hübner) (Lepidoptera:Noctuidae), in Xinjiang, the largest cotton-growing region in China, using a fragment of cytochrome c oxidasesubunit I (COI) gene. Alignments of all 192 COI sequences revealed 28 haplotypes including 23 in southernXinjiang, 5 in eastern Xinjiang and 13 in northern Xinjiang. Negative and significant values of neutrality tests forthe Tajima's D and Fu's FS parameters, combined with the high values of haplotype diversity (Hd), low values ofnucleotide diversity (π) and a high number of low frequency haplotypes indicated a recent demographic expansionof Xinjiang CBW populations. Analysis of molecular variation (AMOVA) indicated low and non-significantgenetic structure, regardless of geographical scale or crop, with most of genetic variation occurringwithin local CBW populations. Pairwise FST analyses also indicated low genetic differentiation. This demographicevent and high gene flow could be responsible for the low genetic structure currently found. CBW populations inXinjiang need to be considered as one panmictic unit in its management, especially for the design of refuges todelay the development of resistance by this migratory pest to transgenic Bt (Bacillus thuringiensis) cotton.
Zhiguo Chen,Xianming Deng,Kun Huang,Wenhuan Zhen,Lei Wang 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4
This paper proposes a sensorless control approach for Wound Rotor Synchronous Machines (WRSMs) based on a high frequency voltage signal injection into the stator side U phase and VW line, respectively. Considering the machine itself as a rotor position sensor, the rotor position observer is established according to the principles of the rotary transformer. A demodulation method for the high frequency signal inducted in the rotor is proposed as well. Simulation and experimental results show that the proposed sensorless control approach has high performance and good practicability.
Chen, Zhiguo,Deng, Xianming,Huang, Kun,Zhen, Wenhuan,Wang, Lei The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4
This paper proposes a sensorless control approach for Wound Rotor Synchronous Machines (WRSMs) based on a high frequency voltage signal injection into the stator side U phase and VW line, respectively. Considering the machine itself as a rotor position sensor, the rotor position observer is established according to the principles of the rotary transformer. A demodulation method for the high frequency signal inducted in the rotor is proposed as well. Simulation and experimental results show that the proposed sensorless control approach has high performance and good practicability.
Gong, Kai,Qu, Bo,Wang, Cairu,Zhou, Jingsong,Liao, Dongfa,Zheng, Wei,Pan, Xianming Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.6
Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by lack of insulin and high glucose levels. T2DM can cause bone loss and fracture, thus leading to diabetic osteoporosis. Promoting osteogenic differentiation of osteoblasts may effectively treat diabetic osteoporosis. We previously reported that Sirtuin 1 (Sirt1), a $NAD^+$-dependent deacetylase, promotes osteogenic differentiation through downregulation of peroxisome proliferator-activated receptor (PPAR) ${\gamma}$. We also found that miR-132 regulates osteogenic differentiation by downregulating Sirt1 in a $PPAR{\beta}/{\delta}$-dependent manner. The ligand-activated transcription factor, $PPAR{\alpha}$, is another isotype of the peroxisome proliferator-activated receptor family that helps maintain bone homeostasis and promot bone formation. Whether the regulatory role of $PPAR{\alpha}$ in osteogenic differentiation is mediated via Sirt1 remains unclear. In the present study, we aimed to determine this role and the underlying mechanism by using high glucose (HG) and free fatty acids (FFA) to mimic T2DM in MC3T3-E1 cells. The results showed that HG-FFA significantly inhibited expression of $PPAR{\alpha}$, Sirt1 and osteogenic differentiation, but these effects were markedly reversed by $PPAR{\alpha}$ overexpression. Moreover, siSirt1 attenuated the positive effects of $PPAR{\alpha}$ on osteogenic differentiation, suggesting that $PPAR{\alpha}$ promotes osteogenic differentiation in a Sirt1-dependent manner. Luciferase activity assay confirmed interactions between $PPAR{\alpha}$ and Sirt1. These findings indicate that $PPAR{\alpha}$ promotes osteogenic differentiation via the Sirt1-dependent signaling pathway.