Creat membership Creat membership
Sign in

Forgot password?

Confirm
  • Forgot password?
    Sign Up
  • Confirm
    Sign In
home > search

Now showing items 33 - 48 of 213

  • A CLUSTER STUDY OF MECHANISM IN THE NEW SUPERCONDUCTORS YBa\r 2\r Cu\r 3\r O\r 7

    Zeng, Zhi   Zheng, Qing-qi   Han, Rushan  

    Download Collect
  • Synchronous determination with double-wavelength by RP-HPLC-UV and optimization of ultrasound-assisted extraction of phenolic acids from Caragana species using response surface methodology

    Zeng, Zhi   Ji, Zhongyin   Hu, Na   Chen, Shasha   Bai, Bo   Wang, Honglun   Suo, Yourui  

    Download Collect
  • AIP Conference Proceedings [AIP REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION: Volume 31 - Burlington, VT (17–22 July 2011)] - Hidden heterogeneous materials recognition in pulsed thermography

    Zeng, Zhi   Tao, Ning   Feng, Lichun   Li, Yue   Zhang, Cunlin  

    Download Collect
  • [IEEE 2010 International Conference on Multimedia Technology (ICMT) - Ningbo, China (2010.10.29-2010.10.31)] 2010 International Conference on Multimedia Technology - A Multi-Core Parallel Fusion Algorithm for Remote-Sensing Image

    Zeng, Zhi   Liu, RenYi   Zhang, Feng   Liu, Nan  

    Download Collect
  • [IEEE 2009 IEEE International Conference on Multimedia and Expo (ICME) - New York, NY, USA (2009.06.28-2009.07.3)] 2009 IEEE International Conference on Multimedia and Expo - A novel approach to musical genre classification using probabilistic latent semantic analysis model

    Zeng, Zhi   Zhang, Shuwu   Li, Heping   Liang, Wei   Zheng, Haibo  

    Download Collect
  • [IEEE 2013 IEEE International Conference on Electro/ Information Technology (EIT) - Rapid City, SD, USA (2013.05.9-2013.05.11)] IEEE International Conference on Electro-Information Technology , EIT 2013 - Image classification using weighted sparsity induced neighbors and label embeddings learning

    Zeng, Zhi   Zhang, Shuwu  

    Download Collect
  • AIP Conference Proceedings [AIP Publishing LLC 40TH ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION: Incorporating the 10th International Conference on Barkhausen Noise and Micromagnetic Testing - Baltimore, Maryland, USA (21–26 July 2013)] - NDT applications of non-contact thermosonics

    Zeng, Zhi   Tao, Ning   Feng, Lichun   Zhang, Cunlin  

    Download Collect
  • [IEEE ICASSP 2011 - 2011 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) - Prague, Czech Republic (2011.05.22-2011.05.27)] 2011 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) - A hierarchical generative model for Generic Audio Document Categorization

    Zeng, Zhi   Zhang, Shuwu  

    Download Collect
  • Fracture toughness of graphene.

    Zhang, Peng   Ma, Lulu   Fan, Feifei   Zeng, Zhi   Peng, Cheng   Loya, Phillip E   Liu, Zheng   Gong, Yongji   Zhang, Jiangnan   Zhang, Xingxiang   Ajayan, Pulickel M   Zhu, Ting   Lou, Jun  

    Perfect graphene is believed to be the strongest material. However, the useful strength of large-area graphene with engineering relevance is usually determined by its fracture toughness, rather than the intrinsic strength that governs a uniform breaking of atomic bonds in perfect graphene. To date, the fracture toughness of graphene has not been measured. Here we report an in situ tensile testing of suspended graphene using a nanomechanical device in a scanning electron microscope. During tensile loading, the pre-cracked graphene sample fractures in a brittle manner with sharp edges, at a breaking stress substantially lower than the intrinsic strength of graphene. Our combined experiment and modelling verify the applicability of the classic Griffith theory of brittle fracture to graphene. The fracture toughness of graphene is measured as the critical stress intensity factor of and the equivalent critical strain energy release rate of 15.9 J m(-2). Our work quantifies the essential fracture properties of graphene and provides mechanistic insights into the mechanical failure of graphene.=20
    Download Collect
  • Arnebin-1 promotes angiogenesis by inducing eNOS,VEGF and HIF-1 alpha expression through the PI3K-dependent pathway

    Zeng, Zhi   Huang, Wen-Dong   Gao, Qi   Su, Mei-Ling   Yang, Yong-Fei   Liu, Zhao-Chun   Zhu, Bang-Hao  

    Arnebin-1, a naphthoquinone derivative, plays a crucial role in the wound healing properties of Zicao (a traditional wound healing herbal medicine). It has been noted that Arnebin-1, in conjunction with vascular endothelial growth factor (VEGF), exerts a synergistic pro-angiogenic effect on human umbilical vein endothelial cells (HUVECs) and accelerates the healing process of diabetic wounds. However, the mechanisms responsible for the pro-angiogenic effect of arnebin-1 on HUVECs and its healing effect on diabetic wounds have not yet been fully elucidated. In this study, in an aim to elucidate these mechanisms of action of arnebin-1, we investigated the effects of arnebin-1 on the VEGF receptor 2 (VEGFR2) and the phosphoinositide 3-kinase (PI3K)-dependent signaling pathways in HUVECs treated with VEGF by western blot analysis. The pro-angiogenic effects of arnebin-1 on HUVECs, including its effects on proliferation and migration, were evaluated by MTT assay, Transwell assay and tube formation assay in vitro. The expression levels of hypoxia-inducible factor (HIF)-1 alpha, endothelial nitric oxide synthase (eNOS) and VEGF were determined by western blot analysis in the HUVECs and wound tissues obtained from non-diabetic and diabetic rats. CD31 expression in the rat wounds was evaluated by immunofluorescence staining. We found that the activation of the VEGFR2 signaling pathway induced by VEGF was enhanced by arnebin-1. Arnebin-1 promoted endothelial cell proliferation, migration and tube formation through the PI3K-dependent pathway. Moreover, Arnebin-1 significantly increased the eNOS, VEGF and HIF-1 alpha expression levels in the HUVECs and accelerated the healing of diabetic wounds through the PI3K-dependent signaling pathway. CD31 expression was markedly enhanced in the wounds of diabetic rats treated with arnebin-1 compared to the wounds of untreated diabetic rats. Therefore, the findings of the present study indicate that arnebin-1 promotes the wound healing process in diabetic rats by eliciting a pro-angiogenic response.
    Download Collect
  • The development of an integrated platform to identify breast cancer glycoproteome changes in human serum

    Zeng, Zhi   Hincapie, Marina   Haab, Brian B.   Hanash, Samir   Pitteri, Sharon J.   Kluck, Steven   Hogan, Jason M.   Kennedy, Jacob   Hancock, William S.  

    Protein glycosylation represents one of the major post-translational modifications and can have significant effects on protein function. Moreover, changes in the carbohydrate structure are increasingly being recognized as an important modification associated with cancer etiology. In this report, we describe the development of a proteomics approach to identify breast cancer related changes in either concentration and/or the carbohydrate structures of glycoprotein(s) present in blood samples. Diseased and healthy serum samples were processed by an optimized sample preparation protocol using multiple lectin affinity chromatography (M-LAC) that partitions serum proteins based on glycan characteristics. Subsequently, three separate procedures, 1D SDS-PAGE, isoelectric focusing and an antibody microarray, were applied to identify potential candidate markers for future study. The combination of these three platforms is illustrated in this report with the analysis of control and cancer glycoproteomic fractions. Firstly, a molecular weight based separation of glycoproteins by 1D SDS-PAGE was performed, followed by protein, glycoprotein staining, lectin blotting and LC-MS analysis. To refine or confirm the list of interesting glycoproteins, isoelectric focusing (targeting sialic acid changes) and an antibody microarray (used to detect neutral glycan shifts) were selected as the orthogonal methods. As a result, several glycoproteins including alpha-1B-glycoprotein, complement 0, alpha-l-antitrypsin and transferrin were identified as potential candidates for further study. (C) 2009 Elsevier B.V All rights reserved.
    Download Collect
  • Modulation of the thermodynamic, kinetic, and magnetic properties of the hydrogen monomer on graphene by charge doping RID G-5770-2010 RID A-4522-2011

    Huang, Liang Feng   Ni, Mei Yan   Zhang, Guo Ren   Zhou, Wang Huai   Li, Yong Gang   Zheng, Xiao Hong   Zeng, Zhi  

    The thermodynamic, kinetic, and magnetic properties of the hydrogen monomer on doped graphene layers were studied by ab initio simulations. Electron doping heightens the diffusion potential barrier, while hole doping lowers it. However, both kinds of dopings heighten the desorption potential barrier. The underlying mechanism was revealed by investigating the effect of charge doping on the bond strength of graphene and on the electron transfer and the coulomb interaction between the hydrogen monomer and graphene. The kinetic properties of H and D monomers on doped graphene layers during both the annealing process (annealing time t(0) = 300 s) and the constant-rate heating process (heating rate alpha = 1.0 K/s) were simulated. Macroscopic diffusion of hydrogen monomers on graphene can be achieved when the doping-hole density reaches 5.0 x 10(13) cm(-2). Both electron and hole dopings linearly reduce the total magnetic moment and exchange splitting, which was explained by a simple exchange model. The laws found in this work had been generalized to explain many phenomena reported in literature. This study can further enhance the understanding of the interaction between hydrogen and graphene and was expected to be helpful in the design of hydrogenated-graphene-based devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3624657]
    Download Collect
  • A Modified Vivaldi Antenna for Improved Angular-Dependent Fidelity Property

    Zeng, Zhi   Xu, Ke   Song, Zhaohui   Zhang, Qinyu  

    The analysis, design, and realization of a modified Vivaldi antenna optimized for time domain fidelity factor in the half-space located in the direction of the antenna main beam are presented. The proposed antenna shows improved angular-dependent fidelity property, with respect to the signal transmitted in the main beam direction. A substantial increase in the fidelity factor is achieved by utilizing spatial filter effect introduced by adding two dielectric slabs parallel to the antenna substrate. By choosing optimal dimensions and location of the slabs, the signal waveforms in the mentioned half-space are equalized so as to improve the quality of the radiated signal waveform in the main beam direction. As a result, the fidelity property in the half-space is improved greatly. The simulated and measured fidelity factor in the angular operational region is studied and compared with experimental measurements. The ranges with the fidelity factor better than the value of 0.9 are improved by 95% in H-plane and by 14% in E-plane, respectively.
    Download Collect
  • Liquid ingress recognition in honeycomb structure by pulsed thermography

    Chen, Dapeng   Zeng, Zhi   Tao, Ning   Zhang, Cunlin   Zhang, Zheng  

    Pulsed thermography has been proven to be a fast and effective method to detect fluid ingress in aircraft honeycomb structure; however, water and hydraulic oil may have similar appearance in the thermal image sequence. It is meaningful to identify what kind of liquid ingress it is for aircraft maintenance. In this study, honeycomb specimens with glass fiber and aluminum skin are injected different kinds of liquids: water and oil. Pulsed thermography is adopted; a recognition method is proposed to first get the reference curve by linear fitting the beginning of the logarithmic curve, and then an algorithm based on the thermal contrast between liquid and reference is used to recognize what kind of fluid it is by calculating their thermal properties. It is verified with the results of theory and the finite element simulation.
    Download Collect
  • Hydrogen influence on generalized stacking fault energies of Zr {0001} basal plane:a first-principles study

    Hou, Songjun   Lei, Huaping   Zeng, Zhi  

    The influence of hydrogen on the Generalized Stacking Fault (GSF) energies of the {0001} basal plane along the < 1010 > and < 1120 > directions in HCP Zr has been investigated by using the first-principles calculations. The variations of GSF energies are studied with respect to different distances of H atoms away from the glide plane and different hydrogen concentrations around the glide plane. The results have shown that the 1/3 < 1010 >{0001} GSF energy is drastically reduced when H atoms are located nearby the glide plane, but H atoms only moderately decrease the 1/3 < 1120 >{0001} GSF energy in proportion. With the increase of H concentration around the glide plane, the GSF energies further greatly reduce with respect to both shift directions. The physical origins of the reduction of GSF energies caused by H atoms have been interpreted based on Bader charge analysis and the structural deformation around the glide plane. The Coulomb repulsion of the positively charged Zr atoms on both sides of the glide plane results in a remarkable decrease of the 1/3 < 1010 >{0001} GSF energy, while the relatively large structural deformation takes precedence over the Coulomb repulsion to determine the 1/3 < 1120 >{0001} GSF energy in the presence of H atoms. Our work proposes a new insight to understand the role of H in the degradation of Zr mechanical performance as cladding materials of nuclear reactors.
    Download Collect
  • The stability of graphene-based Mobius strip with vacancy and at high-temperature

    Yang, Kaishuai   Zhang, Chuanguo   Zheng, Xiaohong   Wang, Xianlong   Zeng, Zhi  

    The structural and electronic properties of mono-vacancy (MV) defect in graphene-based Mobius strip (GMS) are studied in the framework of density functional theory (DFT) combined with the molecular dynamics (MD) simulations. Two kinds of MV defects are observed: the 59-type MV (a configuration with one pentagon and one nonagon ring) located at the curved areas of Mobius strip, and the 5566-type MV (a configuration with two pentagon and two hexagon rings) with one sp(3) hybridized carbon appeared in the twisted areas. The 5566-type MV defect is the most stable configuration at 0 K, while the DFT-MD calculations show that it is unstable at room-temperature and will transform into a 59-type MV. Additionally, the melting behavior of GMSs is investigated through empirical potential MD simulations, and we find that their melting temperatures are about 2750 K, which is lower than that of carbon nanotubes and graphene.
    Download Collect
1 2 3 4 5 6 7 8 9 10

Contact

If you have any feedback, Please follow the official account to submit feedback.

Turn on your phone and scan

Submit Feedback