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Search Results: 1 - 10 of 81402 matches for " Zhenyu Liu "
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LVRT Research of PMSG Wind Turbine Using Feedback Linearization  [PDF]
Jie Wei, Zhenyu Lin, Nian Liu
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B073
Abstract: Analyzing the wind turbine with a direct-driven PMSG, this paper proposes a low voltage ride through scheme of PMSG wind power systems based on feedback linearization. The DC-Link voltage is controlled by the generator-side converter rather than the grid-side converter. Considering the nonlinear relationship between the DC-Link voltage and the generator rotor speed, the controller of DC-Link voltage uses a feedback linearization technology. The grid-side converter which controls the grid active power according to the maximum power point tracking adds a judgment link for the generator speed reference. The model of 2 MW PMSG wind power system was simulated by using PSCAD. The simulation result has verified the validity of the proposed control scheme.
An integrodifferential equation with fractional derivatives in the nonlinearities
Zhenyu Guo and Min Liu
ACTA MATHEMATICA UNIVERSITATIS COMENIANAE , 2013,
Abstract: An integrodifferential equation with fractional derivatives in the nonlinearities is studied in this article, and some sufficient conditions for existence and uniqueness of a solution for the equation is established by contraction mapping principle.
An integrodifferential equation with fractional derivatives in the nonlinearities
Zhenyu Guo,Min Liu
ACTA MATHEMATICA UNIVERSITATIS COMENIANAE , 2013,
Abstract: An integrodifferential equation with fractional derivatives in the nonlinearities is studied in this article, and some sufficient conditions for existence and uniqueness of a solution for the equation is established by contraction mapping principle.
Solvability of a Higher-Order Nonlinear Neutral Delay Difference Equation
Min Liu,Zhenyu Guo
Advances in Difference Equations , 2010, DOI: 10.1155/2010/767620
Abstract:
Solvability of a Higher-Order Nonlinear Neutral Delay Difference Equation
Liu Min,Guo Zhenyu
Advances in Difference Equations , 2010,
Abstract: The existence of bounded nonoscillatory solutions of a higher-order nonlinear neutral delay difference equation , , where , , , and are integers, and are real sequences, , and is a mapping, is studied. Some sufficient conditions for the existence of bounded nonoscillatory solutions of this equation are established by using Schauder fixed point theorem and Krasnoselskii fixed point theorem and expatiated through seven theorems according to the range of value of the sequence . Moreover, these sufficient conditions guarantee that this equation has not only one bounded nonoscillatory solution but also uncountably many bounded nonoscillatory solutions.
Existence of non-oscillatory solutions for a higher-order nonlinear neutral difference equation
Zhenyu Guo,Min Liu
Electronic Journal of Differential Equations , 2010,
Abstract: This article concerns the solvability of the higher-order nonlinear neutral delay difference equation $$ DeltaBig(a_{kn}dotsDeltaig(a_{2n} Delta(a_{1n}Delta(x_n+b_nx_{n-d}))ig)Big) +sum_{j=1}^s p_{jn}f_j(x_{n-r_{jn}})=q_n, $$ where $ngeq n_0ge0$, $d,k,j,s$ are positive integers, $f_j:mathbb{R} o mathbb{R}$ and $xf_j(x)geq 0$ for $x e 0$. Sufficient conditions for the existence of non-oscillatory solutions are established by using Krasnoselskii fixed point theorem. Five theorems are stated according to the range of the sequence ${b_n}$.
MT2 to the Rescue -- Searching for Sleptons in Compressed Spectra at the LHC
Zhenyu Han,Yandong Liu
Physics , 2014, DOI: 10.1103/PhysRevD.92.015010
Abstract: We propose a novel method for probing sleptons in compressed spectra at hadron colliders. The process under study is slepton pair production in R-parity conserving supersymmetry, where the slepton decays to a neutralino LSP of mass close to the slepton mass. In order to pass the trigger and obtain large missing energy, an energetic mono-jet is required. Both leptons need to be detected in order to suppress large standard model backgrounds with one charged lepton. We study variables that can be used to distinguish the signal from the remaining major backgrounds, which include tt, WW+jet, Z+jet, and single top production. We find that the dilepton MT2, bound by the mass difference, can be used as an upper bound to efficiently reduce the backgrounds. It is estimated that sleptons with masses up to about 150 GeV can be discovered at the 14 TeV LHC with 100/fb integrated luminosity.
Study on Co-Effect of K2SO4 Deposition and Low Concentration SO2 on Performances of V2O5/AC Catalysts for Low Temperature SCR  [PDF]
Xianlong Zhang, Bowen Shi, Xueping Wu, Zhanggen Huang, Zhenyu Liu, Baojun Yang, Cuiping Zhang
Advances in Chemical Engineering and Science (ACES) , 2011, DOI: 10.4236/aces.2011.14026
Abstract: Simulated compounds were prepared by loading K2SO4 onto V2O5/AC catalysts. Study the effect of K2SO4 on V1/AC catalysts in the presence of low concentration SO2. Transient response techniques, TPD was carried out. The results indicated that the DeNO activity of V1/AC catalysts was decreased seriously in the early period of operation, but the deactivation was gradually diminished with SO2 adsorption and then, it was completely eliminated. For the sulphated catalysts (saturated catalysts by sulphate), their SCR activity were free from existence of gaseous SO2. the loss of activity about 10% caused by K2SO4 was found on them. The deactivation of K2SO4 deposited catalysts was due to the decrease of adsorbed and activated NH3, or some acid sites.
Molecular Determinants of Resistance Activation and Suppression by Phytophthora infestans Effector IPI-O
Yu Chen,Zhenyu Liu,Dennis A. Halterman
PLOS Pathogens , 2012, DOI: 10.1371/journal.ppat.1002595
Abstract: Despite intensive breeding efforts, potato late blight, caused by the oomycete pathogen Phytophthora infestans, remains a threat to potato production worldwide because newly evolved pathogen strains have consistently overcome major resistance genes. The potato RB gene, derived from the wild species Solanum bulbocastanum, confers resistance to most P. infestans strains through recognition of members of the pathogen effector family IPI-O. While the majority of IPI-O proteins are recognized by RB to elicit resistance (e.g. IPI-O1, IPI-O2), some family members are able to elude detection (e.g. IPI-O4). In addition, IPI-O4 blocks recognition of IPI-O1, leading to inactivation of RB-mediated programmed cell death. Here, we report results that elucidate molecular mechanisms governing resistance elicitation or suppression of RB by IPI-O. Our data indicate self-association of the RB coiled coil (CC) domain as well as a physical interaction between this domain and the effectors IPI-O4 and IPI-O1. We identified four amino acids within IPI-O that are critical for interaction with the RB CC domain and one of these amino acids, at position 129, determines hypersensitive response (HR) elicitation in planta. IPI-O1 mutant L129P fails to induce HR in presence of RB while IPI-O4 P129L gains the ability to induce an HR. Like IPI-O4, IPI-O1 L129P is also able to suppress the HR mediated by RB, indicating a critical step in the evolution of this gene family. Our results point to a model in which IPI-O effectors can affect RB function through interaction with the RB CC domain.
Theoretical calculation of the coefficients of thermal expansion for various AB type halides
Zhang Zhenyu,Ye Danian,Liu Weiling
Chinese Science Bulletin , 1998, DOI: 10.1007/BF02884553
Abstract: By analyzing rhe relationship between thermal expansion coefficients of AB type halides and their crystal chemistry properties, an empirical formula for theoretical calculation of their thermal expansion coefficients is drawn. The formula has a simple form and a high accuracy with an averagc error of 2.4%
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