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Now showing items 209 - 224 of 295

  • Synthesis and characterization of natural polymer/inorganic antibacterial nanocomposites

    Wang Yong   Cheng Shunlin   Wang Fuzhong   Gao Ming   Cao Ruirui  

    In order to increase antibacterial abilities and avoid the aggregation of nanoparticle, Ag-ZnO nanocomposites were studied in the network structure which contains bonds, and these bonds are formed by hydrolysis reaction between Ti(TBOU)(4)(TBOT) and the water that in Persimmon tannin solution. The size and morphology of Ag-ZnO nanocomposites were investigated by scanning electron microscopy (SEM) and field emission scanning electron microscopy(FE-SEM). The antibacterial properties of nanocomposites were examined by minimal bactericidal concentration(MBC). Results showed that this kind of antibacterial nanocomposites composites(ANPs) have excellent antibacterial abilities and without aggregation.
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  • The Preparation of Functionalized Crosslinked Macroporous Chitosan Microspheres and their Adsorption Properties for Bilirubin

    Wu Liping   Wu Weihua   Li Qian   Zhang Qian   Wang Yong   Lu Wei   Zhang Zhengpu  

    glutaraldehyde cross-linked macroporous chitosan microspheres (CS) were prepared by inverse phase suspension reaction with sugar as porogenic agent. The microspheres were modified with different reagents of 1, 6 hexanediamine (HDA) and low generation polyamidoamine (PAMAM) dendrimers including PAMAM G1.0, PAMAM G2.0, PAMAM G3.0. The content of amino groups on CS, CS-PAMAM CS-PAMAM G2.0, CS-PAMAM G3.0, CS-HDA was 3.56, 5.10, 5.47, 6.47, 4.66 mmol/g, respectively. The bilirubin adsorption on the above five microspheres was carried out in 0.05M phosphate buffer solution (pH = 7.2-7.4) at 37 degrees C. The results indicated all the modified CS microspheres were better than unmodified CS microspheres for bilirubin adsorption. CS-HDA has the best adsorption property even if the content of the amino groups was not very high.
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  • Phylogenetic diversity of bacterial endophytes of Panax notoginseng with antagonistic characteristics towards pathogens of root-rot disease complex.

    Ma Li   Cao YongHong   Cheng MingHui   Huang Ying   Mo MingHe   Wang Yong   Yang JianZhong   Yang FaXiang  

    Endophytes play an important role in protection of host plants from infection by phytopathogens. Endophytic bacteria were isolated from five different parts (root, stem, petiole, leaf and seed) of Panax notoginseng and evaluated for antagonistic activity against Fusarium oxysporum, Ralstonia sp. and Meloidogyne hapla, three major pathogens associated with root-rot disease complex of P. notoginseng. From 1000 endophytic bacterial strains evaluated in vitro, 104 strains exhibited antagonistic properties against at least one of these three pathogens. Phylogenetic analyses of their 16S rRNA gene sequences showed that these 104 antagonistic bacteria belong to four clusters: Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes/Chlorobi. Members of the Firmicutes, in particular the Bacillus spp., were predominant in all analyzed tissues. The root was the main reservoir for antagonistic bacteria. Of the 104 antagonists, 51 strains showed antagonistic activities to one pathogen only, while 43 and 10 displayed the activities towards two and all three pathogens, respectively. The most dominant species in all tissues were Bacillus amyloliquefaciens subsp. plantarum and Bacillus methylotrophicus, which were represented by eight strains with broad antagonistic spectrum to the all three test pathogens of root-rot disease complex of P. notoginseng.
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  • Enrichment rules and exploration practices of Paleogene shale oil in Jiyang Depression, Bohai Bay Basin, China

    SONG Mingshui   LIU Huimin   WANG Yong   LIU Yali  

    Based on formation testing data of more than 40 wells with industrial oil flow, systematic observation of 1 010.26 m long cores taken from 4 wells and test data of over 10 000 core samples combining with drilling and pilot fracturing data of multiple wells, the geological characteristics of the upper submember of the Sha 4 Member to the lower submember of the Sha 3 Member of Paleogene(Es4s-Es3x) in the Jiyang Depression were investigated to find out factors controlling the enrichment of shale oil and the accumulation model of shale oil, and a comprehensive evaluation method for shale oil sweet spots was established. It is found through the study that the target shale layer is characterized by strong heterogeneity, weak diagenesis, low thermal evolution and high content of clay and carbonate minerals. Shale lithofacies, microcrack, thin interlayer and abnormal pressure are the main factors affecting enrichment and stable production of shale oil, the organic rich laminar shale has the best storage and oil-bearing capacity, microcrack network system improve the storage capacity and permeability of the shale, the thin interlayer is the main flow channel for stable shale oil production, and the abnormal high pressure layer is rich in free state shale oil and high in oil content. The shale oil layers in the target section were divided into three types: matrix, interlayer and fracture ones. According to the occurrence state and exploration practice of shale oil at home and abroad, it is concluded that the interlayer shale oil is the most profitable type at present. The selection parameters for the different types of shale oil were determined, and accordingly the favorable areas were pointed out by comprehensive evaluation of multiple factors. Vertical wells in the interlayer shale oil reservoir, such as Fan 159, Fan 143 and GX 26, were stimulated by volume fracturing and high conductivity channel fracturing jointly. After fracturing, they had a daily oil production of over 6 t, up to 44 t, and stable productivity. Shale oil is expected to become an important replacement energy resource in the Jiyang Depression.
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  • Preliminary evaluations of FGOALS-g2 for decadal predictions

    Wang Bin   Liu Mimi   Yu Yongqiang   Li Lijuan   Lin Pengfei   Dong Li   Liu Li   Liu Jiping   Huang Wenyu   Xu Shiming   Shen Si   Pu Ye   Xue Wei   Xia Kun   Wang Yong   Sun Wenqi   Hu Ning   Huang Xiaomeng   Liu Hailong   Zheng Weipeng   Wu Bo   Zhou Tianjun   Yang Guangwen  

    The Flexible Global Ocean-Atmosphere-Land System model, Grid-point Version 2 (FGOALS-g2) for decadal predictions, is evaluated preliminarily, based on sets of ensemble 10-year hindcasts that it has produced. The results show that the hindcasts were more accurate in decadal variability of SST and surface air temperature (SAT), particularly in that of Nio3.4 SST and China regional SAT, than the second sample of the historical runs for 20th-century climate (the control) by the same model. Both the control and the hindcasts represented the global warming well using the same external forcings, but the control overestimated the warming. The hindcasts produced the warming closer to the observations. Performance of FGOALS-g2 in hindcasts benefits from more realistic initial conditions provided by the initialization run and a smaller model bias resulting from the use of a dynamic bias correction scheme newly developed in this study. The initialization consists of a 61-year nudging-based assimilation cycle, which follows on the control run on 01 January 1945 with the incorporation of observation data of upper-ocean temperature and salinity at each integration step in the ocean component model, the LASG IAP Climate System Ocean Model, Version 2 (LICOM2). The dynamic bias correction is implemented at each step of LICOM2 during the hindcasts to reduce the systematic biases existing in upper-ocean temperature and salinity by incorporating multi-year monthly mean increments produced in the assimilation cycle. The effectiveness of the assimilation cycle and the role of the correction scheme were assessed prior to the hindcasts.
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  • Study on Relationship between Tobacco Canopy Spectra and LAI

    Hongbo Qiao   Weng Mei   Yafei Yang   Wang Yong   Jishuai Zhang   Yu Hua  

    N nutrition is one of the most important limitation factors for crop growth and yield. Precise and timely monitoring and detection of crop N nutrient conditions is necessary for improving the efficiency of N nutrition using and crop management; reducing environmental pollution caused by over nitrogen fertilizer application. In this paper the canopy reflectance spectra during the whole growth period on tobacco field plots treated with different nitrogen levels were periodically and continually measured. LAI of tobacco of several important growth periods was meanwhile measured. The results showed that tobacco canopy spectral reflectance of different growing periods changed regularly with the increase of nitrogen fertilizer application.The canopy spectral reflectance increased in 7l0~1000 nm;while decreased in 460~680 nm. There was high correlations between NDVI and LAI. The research supply theoretical foundation for tobacco N management.
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  • Method and application effect of recognizing seismic multiples based on VSP data

    In the seismic exploration of reflection wave, multiple wave is a kind of common interference wave which has serious influence on effective information. The appearance and existence of multiple waves make the seismic imaging unreal, distort the amplitude, frequency and phase of the reflected wave of the target layer, and affect the authenticity and reliability of the seismic imaging. Attenuation of multiple waves is always a difficult problem in seismic data processing. With the development of seismic exploration to lithologic exploration and reservoir description, people pay more and more attention to the multiple wave problem. Therefore, how to suppress multiple waves effectively becomes a key problem in seismic exploration. In view of the formation mechanism of multiple waves, this paper uses the unique observation method of VSP to accurately identify multiple waves, guide the effective suppression of multiple waves, and improve the accuracy and reliability of seismic data processing results.
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  • Effect of astragaloside Ⅳ on lipid and glucose metabolism in acute myocardial infarction through PPARγ pathway

    ZHANG Qian   WANG Xiao-ping   WANG Yong   LI Chun   WANG Wei  

    OBJECTIVE To investigate the effects of astragaloside IV(which can be extracted from the traditional Chinese medicine Astragalus membranaceus) on lipid and glucose metabolism in acute myocardial infarction(AMI).METHODS Model of heart failure(HF) after AMI was established with ligation of left anterior descending artery on Sprague-Dawley(SD) rats. The rats were divided into three groups: sham, model and astragaloside IV treatment group.Twenty-eight days after treatment(astragaloside IV, 20 mg·kg~(-1) daily), hematoxylin-eosin(HE) staining was applied to visualize cardiomyocyte morphological changes. High performance liquid chromatography(HPLC) was performed to assess the contents of adenosine phosphates in heart. Positron emission tomography and computed tomography(PET-CT)was conducted to evaluate the cardiac glucose metabolism. Expressions of key molecules such as peroxisome proliferatoractivated receptor γ(PPARγ), sterol carrier protein 2(SCP2) and long chain acyl Co A dehydrogenase(ACADL) were measured by Western blotting and immunohistochemistry. Oxygen-glucose deprivation-reperfusion(OGD/R)-induced H9 C2 injury cardiomyocyte model was adopted for potential mechanism research in vitro. RESULTS Treatment with astragaloside Ⅳ rescued hearts from structural and functional damages as well as inflammatory infiltration. Levels of adenosine triphosphate(ATP) and energy charge(EC) in astragaloside IV group were also up-regulated compared to model group. Further results demonstrated that critical enzymes both in lipid metabolism and glucose metabolism compromised in model group compared to sham group. Intriguingly, astragaloside Ⅳ could up-regulate critical enzymes including ACADL and SCP2 in lipid metabolism accompanying with promoting effect on molecules in glycolysis simultaneously.Results on upstreaming signaling pathway demonstrated that astragaloside Ⅳ could dramatically increase the expressions of PPARγ. In vitro study suggested the efficacy of astragaloside Ⅳ could be blocked by T0070907, a selective PPARγ inhibitor. CONCLUSION Astragaloside IV has cardioprotective effect in improving cardiac function and energymetabolism through regulating lipid and glucose metabolism. The effects may be mediated by PPARγ pathway.
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  • Face detection model based on distance measure of regional feature

    Yu Hengyong   Wang Yong   Mou Xuanqin   Cai Yuanlong  

    This paper proposes a new model for face detection based on statistics by applying the mosaic method. The model is insensitive to illumination and can adapt to the distortion and slope of face in some degrees. Moreover, there is an extra good feature of this model, i.e., an attention focusing capability. First, a distance measure, that is the Mahalanobis distance (MD), is presented, which is suitable for vector clustering. Next, the standard deviation of gradient norm and direction angle in each mosaic block are selected as the regional features in the model. The tested images are detected as human faces when both the MDs of the gradient norm and the direction angle to the collectivity of human faces are small. Finally, some experiments were made under different conditions and the results obtained show the model performed as expected
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  • Clustering analysis based on Genetic Algorithms

    Wang Yong   Zhang Wei  

    Genetic algorithm is optimal mathematical search technique based on the principles of natural selection and genetic recombination. Therefore, to make clustering analysis process automation, a hybrid method combining genetic algorithm and clustering algorithm has been applied. Then, the best clustering result can be obtained. According to the simulation results, the proposed algorithm outperforms several existing approaches such as FCM, SOM.
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  • Research on Supply Chain Pricing Mechanism Decision Based on Multiple Retailers

    Wang Yong   Tang Bing Yong   Xu Xiao li  

    The pricing decision of supply chain based on Stackelberg is studied. With game theory, matrix analysis and optimization method, this paper analyses two non-coordination mechanisms which are Stackelberg Tariff and w=c Tariff and one coordination mechanism which is Perfect coordination Tariff in the setting of one supplier and multiple retailers who compete in price. The analysis shows that whether the supplier adopts coordination mechanism will depend on concrete circumstance.
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  • Major Tectono-thermal Events in the Yangtze Craton: Insights from U-Pb-Lu-Hf Isotope Records in Zircons from End-Permian Volcanic Interlayers in Southwest China

    SHI Zejin   LI Wenjie   ZHANG Jin   TIAN Yaming   WANG Yong   YIN Guan   LUO Qichao  

    The in situ zircon U-Pb-Lu-Hf isotope records from end-Permian volcanic interlayers in southwest China, integrated with previous studies, restructure the evolutionary history of the Yangtze Craton from Precambrian to Late Paleozoic. This includes early continental crust formation before ~3.0 Ga and massive juvenile crustal growth at 2.6–2.4 Ga; large-scale crustal reworking at ~2.1–1.7 Ga; Neoproterozoic crust addition at ~1.1 to 0.7 Ga; collision and subduction along the craton margin between ~700–541 Ma; Early Ordovician to Late Silurian magmatism; and large tectono-thermal events in the Middle Carboniferous to end-Permian. Some zircons with T
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  • Adiabatic limits, vanishing theorems and the non-commutative residue

    Liu KeFeng   Wang Yong  

    In this paper, we compute the adiabatic limit of the scalar curvature and prove several vanishing theorems by taking adiabatic limits. As an application, we give a Kastler-Kalau-Walze type theorem for foliations.
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  • Asymptotic analysis of nonlinear micro-film buckling

    Ying ZuGuang   Wang Yong   Zhu ZeFei  

    The buckling design of micro-films has various potential applications to engineering. The substrate prestrain, interconnector buckling amplitude and critical strain are important parameters for the buckling design. In the presented analysis, the buckled film shape was described approximately by a trigonometric function and the buckled film amplitude was obtained by minimizing the total strain energy. However, this method only generates the first-order approximate solution for the nonlinear buckling. In the present paper, an asymptotic analysis based on the rigorous nonlinear differential equation for the buckled micro-film deformations is proposed to obtain more accurate relationship of the buckling amplitude and critical strain to prestrain. The obtained results reveal the nonlinear relation and are significant to accurate buckling design of micro-films.
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  • A new SILO process for VLSI isolation using N2+ ion implantation : Duan Li, Li Weizhong, Wang Yong and Lin Yufeng. Vacuum 39(2–4), 211 (1989)

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  • Single-and two-phase flow model in low-permeability reservoir

    Song Fuquan   Song Xingxing   Wang Yong   Sun Yeheng  

    In petroleum development,low-permeability reservoir means having permeability of porous media lower than 50 micro-Darcy.The mathematical model of liquid flow in low-permeability reservoirs has been difficult to describe for a long time,and an ideal model has not been available until now because of the threshold pressure gradient.With the boundary adhesion layer model of a micro-channel as basis,a new liquid flow model was derived for low-permeability reservoirs in this study.The no-movement liquid layer close to the solid surface was defined as the boundary adhesion layer regarded as the negative slip length.Using the exponential function of the boundary stick layer to the pressure drop gradient,the formulae of the liquid velocity and flow rate of a round channel were derived.The liquid flows model in low permeability reservoirs was then obtained.Finally,the flow model was tested by examples,and applications to a low-permeability reservoir were demonstrated.The analysis results show that the new non-linear model of liquid flows exhibits clear physical definition,and can be easily used to describe liquid flows in low-permeability media.
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