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A novel method for identifying rotor-stator rubbing positions using the cepstrum analysis technique
Guo Chen,Yong-Quan Liu,Guang-Yi Jiang,Cheng-Gang Li,Guo-Quan Feng,De-You Wang 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.9
A novel method of aero-engine rubbing positions identification based on cepstrum analysis is proposed, and the transfer path characteristicswhich reflect the transfer characteristics information from rubbing points to casing measuring points are separated from the vibrationacceleration signals of casing by means of cepstrum analysis. Therefore, there is different transfer characteristics information atdifferent rubbing positions, and in view of this, twenty rubbing positions identification features from the cepstrum are extracted. A largenumber of rubbing experiments of different positions are simulated with the rotor experiment rig of aero-engine, and the characteristicanalysis of experimental samples at different rubbing positions is carried out, and the results indicate the consistency of features to thesame rubbing position and the difference of the features to the different rubbing positions. Finally, the aero-engine rubbing positionsidentification is carried out using the nearest neighbor classification method, the recognition rate reaches 100%, and the effectiveness ofthe method is full verified.
Quantitative Assessment of the Effects of MMP-2 Polymorphisms on Lung Carcinoma Risk
Guo, Xiao-Tong,Wang, Jun-Feng,Zhang, Lin-You,Xu, Guang-Quan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.6
Background: Previous studies assessing associations between matrix metalloproteinase 2 (MMP-2) polymorphisms and lung cancer risk reported conflicting results. A meta-analysis was therefore performed to derive a more precise estimation. Method: Case-control studies assessing associations between MMP-2 C735T and C1306T polymorphisms and lung cancer risk were included. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were estimated. Results: 7 studies with a total of 3,189 lung cancer cases and 3,013 controls were finally included into this meta-analysis. Overall, the MMP-2 C735T polymorphism was associated with lung cancer risk under the homozygote model (CC versus TT: OR =1.44, 95% CI = 1.03-2.02, $I^2$ = 0%), while the MMP-2 C1306T polymorphism also associated demonstrated links with all four models (all P values less than 0.05). Subgroup analyses by race suggested obvious associations between MMP-2 C735T and C1306T polymorphisms and lung cancer risk in Asians but not in Caucasians. There was no evidence for publication bias. Conclusion: Currently available evidence supports teh conclusion that MMP-2 C735T and C1306T polymorphisms influence susceptibility to lung cancer in Asians.
Modelling of the Hot Flow Behaviors for Ti-13Nb-13Zr Alloy by BP-ANN Model and Its Application
Guo-zheng Quan,Shi-ao Pu,Zong-yang Zhan,Zhen-yu Zou,Ying-ying Liu,Yu-feng Xia 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.
The plastic deformation mechanisms and the constitutive model of flow behaviors at different deformation conditions in biomedical titanium alloy are an essential step to optimize the design of any forging process for implant productions. A series of isothermal compressions tests on Ti-13Nb-13Zr alloy in a wide range of true strain, temperature and strain rate were conducted on a thermomechanical simulator. The hot flow behaviors with different softening mechanisms, including dynamic recrystallization and dynamic recovery, were characterized based on true strain-stress curves. A back-propagational artificial neural network (BP-ANN) method was conducted to evaluate and predict this non-linear problem by self-training to be adaptable to the material characteristics. The flow stress of this material a wide deformation condition range can be predicted accurately by the BP-ANN model obtained in this study. The prediction ability of this BP-ANN Model was evaluated by three accuracy indexes, Absolute error, Relative error and Average absolute relative error. Sequently, the developed BP-ANN model was programed and implanted into the finite element (FE) analysis platform, Msc.Marc software. The results have sufficiently articulated that the well-trained ANN model has excellent capability to deal with the complex flow behaviors and has great application potentiality in hot deformation processes.
TETRAVALENT SYMMETRIC GRAPHS OF ORDER 9p
Guo, Song-Tao,Feng, Yan-Quan Korean Mathematical Society 2012 대한수학회지 Vol.49 No.6
A graph is symmetric if its automorphism group acts transitively on the set of arcs of the graph. In this paper, we classify tetravalent symmetric graphs of order $9p$ for each prime $p$.
Yong Quan,Guo Qiang Fub,Zi Feng Huang,Ming Gu 한국풍공학회 2020 한국풍공학회지 Vol.24 No.4
The statistical characteristics of typhoon wind speed records tend to have a considerable time-varying trend; thus, the stationary wind model may not be appropriate to estimate the wind characteristics of typhoon events. Several nonstationary wind speed models have been proposed by pioneers to characterize wind characteristics more accurately, but comparative studies on the applicability of the different wind models are still lacking. In this study, three landfall typhoons, Ampil, Jongdari, and Rumbia, recorded by ultrasonic anemometers atop the Shanghai World Financial Center (SWFC), are used for the comparative analysis of stationary and nonstationary wind characteristics. The time-varying mean is extracted with the discrete wavelet transform (DWT) method, and the time-varying standard deviation is calculated by the autoregressive moving average generalized autoregressive conditional heteroscedasticity (ARMA-GARCH) model. After extracting the time-varying trend, the longitudinal wind characteristics, e.g., the probability distribution, power spectral density (PSD), turbulence integral scale, turbulence intensity, gust factor, and peak factor, are comparatively analyzed based on the stationary wind speed model, time-varying mean wind speed model and time-varying standard deviation wind speed model. The comparative analysis of the different wind models emphasizes the significance of the nonstationary considerations in typhoon events. The time-varying standard deviation model can better identify the similarities among the different typhoons and appropriately describe the nonstationary wind characteristics of the typhoons.
Wei Guo,Yan Li,Chao Sun,Hui-Quan Duan,Shen Liu,Shi-Qing Feng,Yun-Qiang Xu 한국통합생물학회 2017 Animal cells and systems Vol.21 No.2
Myelin formation during peripheral nervous system development, as well as myelin repair after injury and in disease, requires multiple intrinsic and extrinsic signals. Neurotrophin-4 (NT-4) is a member of the neurotrophin family, which regulates the development of neuronal networks by participating in the growth of neuronal processes, synaptic development and plasticity, neuronal survival, and differentiation. However, the intracellular signaling pathways by which NT-4 participates in myelination by Schwann cells remain elusive. In this study, we examined the effects of NT-4 on the expression of compact myelin proteins in cultured Schwann cells. Using real-time quantitative RT-PCR and western blotting, we found that NT-4 could significantly enhance the expression of myelin protein zero (MPZ) but not the expression of myelin basic protein or peripheral myelin protein 22. Further, knockdown of truncated TrkB with small interfering RNA could eliminate the effect of NT-4 on MPZ expression. Moreover, we demonstrated that the NT-4-enhanced MPZ expression depended on Akt and mTORC1 signaling. Taken together, these results suggest that NT-4 binds TrkB to enhance the expression of MPZ in Schwann cells, probably through the PI3K/Akt/mTORC1 signaling pathway, thus contributing to myelination.
Integrated Protection Unit Design for Power Networks
Zhan-feng Fan,Sheng-ming Ge,Z Q Bo,Lin Wang,Feng-quan Zhou,Xing Liu,Guo-bing Song 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.4
This paper presents an hardware design solution for integrated protection of distribution systems (Network Protection Unit) by combining transient polarity comparison technique, which is based on the detection and processing of fault generated transient current signals. The integrated protection relays installed at each substation of a distribution network are communicated with the Network Protection Unit through specially designed Packet Transport Network (PTN) for fast and reliable transmission of transient polarity current signals. The relay detects the faulted generated super-imposed current signals. The transient polarity identification algorithm is then applied to the super-imposed signals to identify the polarity of the signal detected. The Network Protection Unit can collect all the transient polarity current signals under its protection area. Then The direction of a fault is determined by comparison of the polarity of the signals derived from all the line sections connected to the substation. The actual faulted section is identified by the Network Protection Unit through comparing the directional information from various stations. Simulation results presented in the paper demonstrate the feasibility of the scheme.
Deployment Dynamics of Large-Scale Flexible Solar Arrays with Deployable Mast
Hai-Quan LI,Xiao-Feng LIU,Shao-Jing GUO,Guo-Ping CAI 한국항공우주학회 2017 International Journal of Aeronautical and Space Sc Vol.18 No.2
In this paper, deployment dynamics of large-scale flexible solar arrays with deployable mast is investigated. The adopted solar array system is introduced firstly, then kinematic description and kinematic constraint equations are deduced, and finally, dynamics equation of the system is established by the Jourdain velocity variation principle and a new method to deal with topology changes of the deployable mast is introduced. The dynamic behavior of the system is studied in detail. Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the solar arrays and that the introduced method is applicable for topology changes.