• 제목/요약/키워드: Li Gao

검색결과 446건 처리시간 0.02초

Design, Synthesis and Antifungal Activities of Novel Strobilurin Derivatives Containing Pyrimidine Moieties

  • Zhang, Xiang;Gao, Yong-Xin;Liu, Hui-Jun;Guo, Bao-Yuan;Wang, Hui-Li
    • Bulletin of the Korean Chemical Society
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    • 제33권8호
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    • pp.2627-2634
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    • 2012
  • Strobilurins are one of the most important classes of agricultural fungicides. To discover new strobilurin derivatives with high activity against resistant pathogens, a series of novel ${\beta}$-methoxyacrylate analogues were designed and synthesized by integrating substituted pyrimidine with a strobilurin pharmacophore. The compounds were confirmed and characterized by infrared, $^1H$ nuclear magnetic resonance, elemental analysis and mass spectroscopy. The bioassays indicated that most of the compounds (1a-1h) exhibited potent antifungal activities against Colletotrichum orbiculare, Botrytis cinerea Pers and Phytophthora capsici Leonian at the concentration of 50 ${\mu}g/mL$. Exhilaratingly, compound 1d (R=3-trifluoromethylphenyl) showed better antifungal activity against all the tested fungi than the commercial strobilurin fungicide azoxystrobin.

Dominant failure modes identification and structural system reliability analysis for a long-span arch bridge

  • Gao, Xin;Li, Shunlong
    • Structural Engineering and Mechanics
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    • 제63권6호
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    • pp.799-808
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    • 2017
  • Failure of a redundant long-span bridge is often described by innumerable failure modes, which make the structural system reliability analysis become a computationally intractable work. In this paper, an innovative procedure is proposed to efficiently identify the dominant failure modes and quantify the structural reliability for a long-span bridge system. The procedure is programmed by ANSYS and MATLAB. Considering the correlation between failure paths, a new branch and bound operation criteria is applied to the traditional stage critical strength branch and bound algorithm. Computational effort can be saved by ignoring the redundant failure paths as early as possible. The reliability of dominant failure mode is computed by FORM, since the limit state function of failure mode can be expressed by the final stage critical strength. PNET method and FORM for system are suggested to be the suitable calculation method for the bridge system reliability. By applying the procedure to a CFST arch bridge, the proposed method is demonstrated suitable to the system reliability analysis for long-span bridge structure.

Numerical investigations of tip clearance flow characteristics of a pumpjet propulsor

  • Lu, Lin;Gao, Yuefei;Li, Qiang;Du, Lin
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제10권3호
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    • pp.307-317
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    • 2018
  • In this study, numerical investigations of the tip clearance flow characteristics of a pumpjet propulsor based on Computational Fluid Dynamics (CFD) method have been presented. The Zwart-Gerber-Belamri (Z-G-B) cavitation model based on Reynolds Averaged Navier-Stokes (RANS) method is employed. The structured gird is applied. The formation and development of the tip clearance flows has been investigated and presented. The structure of the tip leakage vortex has been shown. The radial distributions of different velocity components with different Span along the axial direction have been carried out to present the influence of the tip clearance flow on the main flow. In addition, the influences of the tip clearance size on the pumpjet propulsor performance, including the impact on the velocity flow fields and the cavitation characteristic, have been presented.

Novel Filtering Power Divider with External Isolation Resistors

  • Lu, Yun-Long;Wang, Shun;Dai, Gao-Le;Li, Kai
    • ETRI Journal
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    • 제37권1호
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    • pp.61-65
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    • 2015
  • In this paper, a novel filtering power divider with external isolation resistors is presented. The proposed power divider can be considered as an integration of a bandpass filter and a Gysel power divider. Based on the circuit topology, a high-order filtering power divider can be easily realized. Odd- and even-mode models are employed to analyze the filtering and power splitting functions. For demonstration, a third-order filtering power divider operating at 1.5 GHz is designed and implemented. The measured results exhibit an isolation between the output ports that is better than 20 dB at around the center frequency.

Impact of Outdated CSI on the Performance of Incremental Amplify-and-Forward Opportunistic Relaying

  • Zhou, Tsingsong;Gao, Qiang;Fei, Li
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제10권6호
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    • pp.2567-2582
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    • 2016
  • This paper investigates the impact of outdated channel state information (CSI) on the performance of the incremental amplify-and-forward (AF) opportunistic relaying (OR) over dual-hop Rayleigh fading channels. According to the definition of distribution function, we obtain the cumulative distribution function (CDF) of the actual combined signal-to-noise ratio (SNR) received at the destination. Based on this CDF, the closed-form expressions of the average spectral efficiency and outage probability are derived for the incremental AF OR under outdated CSI. Numerical results show that in the low region of the average SNR of the direct link, outdated CSI deteriorates the system performance, whereas in the high region, outdated CSI has almost no impact on the system performance.

Accelerated Split Bregman Method for Image Compressive Sensing Recovery under Sparse Representation

  • Gao, Bin;Lan, Peng;Chen, Xiaoming;Zhang, Li;Sun, Fenggang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제10권6호
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    • pp.2748-2766
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    • 2016
  • Compared with traditional patch-based sparse representation, recent studies have concluded that group-based sparse representation (GSR) can simultaneously enforce the intrinsic local sparsity and nonlocal self-similarity of images within a unified framework. This article investigates an accelerated split Bregman method (SBM) that is based on GSR which exploits image compressive sensing (CS). The computational efficiency of accelerated SBM for the measurement matrix of a partial Fourier matrix can be further improved by the introduction of a fast Fourier transform (FFT) to derive the enhanced algorithm. In addition, we provide convergence analysis for the proposed method. Experimental results demonstrate that accelerated SBM is potentially faster than some existing image CS reconstruction methods.

GPR78 promotes lung cancer cell migration and metastasis by activation of Gαq-Rho GTPase pathway

  • Dong, Dan-Dan;Zhou, Hui;Li, Gao
    • BMB Reports
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    • 제49권11호
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    • pp.623-628
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    • 2016
  • GPR78 is an orphan G-protein coupled receptor (GPCR) that is predominantly expressed in human brain tissues. Currently, the function of GPR78 is unknown. This study revealed that GPR78 was expressed in lung cancer cells and functioned as a novel regulator of lung cancer cell migration and metastasis. We found that knockdown of GPR78 in lung cancer cells suppressed cell migration. Moreover, GPR78 modulated the formation of actin stress fibers in A549 cells, in a RhoA- and Rac1-dependent manner. At the molecular level, GPR78 regulated cell motility through the activation of $G{\alpha}q$-RhoA/Rac1 pathway. We further demonstrated that in vivo, the knockdown of GPR78 inhibited lung cancer cell metastasis. These findings suggest that GPR78 is a novel regulator for lung cancer metastasis and may serve as a potential drug target against metastatic human lung cancer.

Study on Dormancy Mechanisms of American Ginseng Seed II - Germination Inhibition of Seed Coat

  • Huang, Yao-Ge;Li, Xiang-Gao;Cui, Shu-Yu;Yang, Ji-Xiang;Liu, Ren-Song;Kim, Hack-Seang
    • Natural Product Sciences
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    • 제2권2호
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    • pp.137-142
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    • 1996
  • This paper gives a description about the germination inhibition of American ginseng (Panax quinquefolium L.) seed coat. The existence of seed coat is one of the inhibitory factors which inhibit the embryo growth, particularly during the morphological after-ripening stage. The seed coat can obstruct the water absorption at the beginning of seed stratification, but it can not threaten seed germination. The inhibition of seed coat is not caused by the mechanical fetter neither. However, before splitting the seed coat, the inhibition of seed coat comes from both air-tight character and inhibitors, and after splitting the seed coat, the inhibition may come mainly from the inhibitors.

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TIGHT TOUGHNESS CONDITION FOR FRACTIONAL (g, f, n)-CRITICAL GRAPHS

  • Gao, Wei;Liang, Li;Xu, Tianwei;Zhou, Juxiang
    • 대한수학회지
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    • 제51권1호
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    • pp.55-65
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    • 2014
  • A graph G is called a fractional (g, f, n)-critical graph if any n vertices are removed from G, then the resulting graph admits a fractional (g, f)-factor. In this paper, we determine the new toughness condition for fractional (g, f, n)-critical graphs. It is proved that G is fractional (g, f, n)-critical if $t(G){\geq}\frac{b^2-1+bn}{a}$. This bound is sharp in some sense. Furthermore, the best toughness condition for fractional (a, b, n)-critical graphs is given.