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Search Results: 1 - 10 of 39445 matches for " GENG Yan "
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Advances in Somatic Embryogenesis Research of Horticultural Plants  [PDF]
Aiqing Ji, Xueqing Geng, Yan Zhang, Guoliang Wu
American Journal of Plant Sciences (AJPS) , 2011, DOI: 10.4236/ajps.2011.26087
Abstract: Advances in horticulture plant biotechnologies provide new opportunities for researchers to study the field of vegetative propagation and genetic engineering. Developments of clonal propagation methods, especially somatic embryogenesis (SE), have numerous potential applications. This paper reviewed progress of research on SE in horticultural plants in last decade; analyzed plant regeneration having both direct and indirect SE from the characteristics of occurrence means, but mainly in an indirect way; and discussed the impact factors of SE, as well as reviewed the research in the practical applications of horticulture plants SE in the practice.
Recent developments of the stoichiometric displacement model for separation processes
Xindu Geng,Fred E. Regnier,Yan Wang
Chinese Science Bulletin , 2001, DOI: 10.1007/BF02900546
Abstract: Substantial attention has been paid to the stoichiometric displacement models for solute retention (SDM-R) in liquid chromatography and adsorption (SDM-A) at surfaces since they were developed. The SDM has a strongly theoretical basis and has evolved to the point that it is widely applied in chemistry, biochemistry, molecular biology and biotechnology. This review introduces the history, recent developments, and new concepts relating to the SDM, including theory, mathematical expressions, and applications across a broad range of fields.
Three solutions for singular p-Laplacian type equations
Zhou Yang,Di Geng,Huiwen Yan
Electronic Journal of Differential Equations , 2008,
Abstract: In this paper, we consider the singular $p$-Laplacian type equation $$displaylines{ -hbox{div}(|x|^{-eta} a(x, abla u)) =lambda f(x,u),quad hbox{in }Omega,cr u=0,quad hbox{on }partialOmega, }$$ where $0leqeta Keywords p-Laplacian operator --- singularity --- multiple solutions
Growth Kinetics of Monodisperse Polystyrene Microspheres Prepared by Dispersion Polymerization
Fan Li,Chong Geng,Qingfeng Yan
Journal of Polymers , 2013, DOI: 10.1155/2013/754687
Abstract: Dispersion polymerization has been widely applied to the synthesis of monodisperse micron-sized polymer colloidal spheres. Many efforts have been devoted to studying the influence of initial conditions on the size and uniformity of the resultant microspheres, aiming to synthesize micron-size monodisperse colloidal spheres. However, the inner contradiction between the size and the size distribution of colloidal spheres hinders the realization of this goal. In this work, we drew our attention from the initial conditions to the growth stage of dispersion polymerization. We tracked the size evolution of colloidal sphere during the dispersion polymerization, through which we established a kinetic model that described the relationship between the monomer concentration and the reaction time. The model may provide a guideline to prepare large polymer colloidal spheres with good monodispersity by continuous monomer feeding during the growth stage to maintain the concentration of monomer at a constant value in a dispersion polymerization process. 1. Introduction As a new functional macromolecule material, monodisperse polymer microspheres have many applications in environmental conservation, biomedicine, colloid science, electronic information material, and many other areas [1–3] due to their superiority of good sphericity, size tunability, large specific surface area, and excellent absorbability [4–6]. Particularly, monodisperse micron-sized spheres are ideal materials as advanced coatings [7], fillers of chromatographic column [8, 9], standard particles of electron microscope and Coulter particle size testers, and spacers in LCD [10], which has drawn increasing interest to synthesize monodisperse micron-sized spheres [11, 12]. The first report on monodisperse polymer colloidal spheres was the polystyrene spheres prepared by Vanderhoff and Brandford [13]. So far, many synthesis strategies have been developed such as emulsion polymerization, suspension polymerization, dispersion polymerization, and seed swelling polymerization. In view of the demand of micron size and monodispersity, the former two methods are excluded because they cannot meet the two requirements at the same time. Emulsion polymerization can only gain monodisperse colloidal spheres with the size below 1?μm. Suspension polymerization may achieve large microspheres with size ranging from 10?μm to 100?μm while the microspheres possess a bad monodispersity [14]. The latter two methods are suitable for the synthesis of uniform colloidal spheres with micron size. Seed swelling polymerization,
Research on How to Deal with the Dilemma of Global Cooperative Governance of Cross-Border Telecom Network Fraud in China  [PDF]
Yingchao Geng
Chinese Studies (ChnStd) , 2017, DOI: 10.4236/chnstd.2017.64023
Abstract: The rapid growth of cross-border telecom network fraud in the globalized information ocean and the economic tide has posed a threat to China and the global security and stability, and its governance is imminent. Under the analysis framework of global collaborative governance, this paper analyzes the external environmental factors and related internal governance factors, such as the background of cross-border telecom network fraud governance, which needs our attention. From the level of synergetic governance and the autonomy of the subject, the analysis of this paper draws a conclusion that cross-border telecom network fraud improvement is confronted with many dilemmas, for instance, the difficulty in reaching a consensus of values, the malconformation of legal norms, the high pressure of public opinion and the weakness of human nature. The paper puts forward the countermeasures based on Chinese perspective, from four aspects of value guidance, legal soundness, system regulation and technical complementation to work with all parties to manage the main forces, to combat and prevent cross-border telecommunications network fraud, achieving a good prospect of shared governance.
Rapid solidification of acoustically levitated Al-Cu-Si eutectic alloy under laser irradiation
Na Yan,DeLu Geng,ZhenYu Hong,BingBo Wei
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4403-5
Abstract: Al-27%Cu-5.3%Si ternary eutectic alloy was melted using a YAG laser and then solidified while being acoustically levitated. A maximum undercooling to 195 K (0.24 T L) was achieved with a cooling rate of 76 K/s. The solidification microstructure was composed of (Al+θ+Si) ternary eutectics and (Al+θ) pseudobinary eutectics. During acoustic levitation, the (Al+θ+Si) ternary eutectics are refined and the (Al+θ) pseudobinary eutectics have morphological diversity. On the surface of the alloys, surface oscillations and acoustic streaming promote the nucleation of the three eutectic phases and expedite the cooling process. This results in the refinement of the ternary eutectic microstructure. During experiments, the reflector decreases with increasing alloy temperature, and the levitation distance always exceeds the resonant distance. Because of the acoustic radiation pressure, the melted alloy was flattened, and deformation increases with increasing sound pressure. The maximum aspect ratio achieved was 6.64, corresponding to a sound pressure of 1.8×104 Pa.
The ninth-mode sectorial oscillation of acoustically levitated drops
ZhenLin Yan,WenJun Xie,DeLu Geng,BingBo Wei
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4698-2
Abstract: We report on the ninth-mode sectorial oscillation of acoustically levitated drops excited by actively modulating sound pressure. A numerical computation based on the level set method was performed to model drop shape evolution by solving an incompressible two-phase flow problem. The calculated shapes of the oscillating drop are in good agreement with experimental observations. The relationship between the oscillation frequency and parameters describing the flattened drops is studied both experimentally and numerically. The frequency of the ninth-mode sectorial oscillation decreases with increasing equatorial radius and can be well-described by a modified Rayleigh equation.
A Comprehensive Facet Model for Bistatic SAR Imagery of Dynamic Ocean Scene
Yan Wei Zhao;Min Zhang;Xupu Geng;Ping Zhou
PIER , 2012, DOI: 10.2528/PIER11100910
Abstract: A comprehensive facet model for bistatic synthetic aperture radar (Bis-SAR) imagery of dynamic ocean scene is presented in this paper. An efficient facet scattering model is developed to calculate the radar cross section (RCS) of the ocean surface for Bis-SAR firstly. Further more, this facet model is combined with a bistatic velocity bunching ($VB$) modulation of long ocean waves to obtain the Bis-SAR intensity expression in image plane of ocean scene. The displacement of the scatter elements in the image plane and the degradation of radar resolution in azimuth direction are quantificationally analyzed. Finally, Bis-SAR imagery simulations of ocean surface are illustrated, proving the validity and practicability of the presented algorithms.
Calcium overload injury of rats' enterocyte IEC-6 by heat stress in vitro
Yan GENG,Ya-nan LIU,Wei FU,Na PENG
Medical Journal of Chinese People's Liberation Army , 2013,
Abstract: Objective To investigate the effect of gradient heat stress on calcium overload of rats' enterocyte IEC-6 and calcium overload-related cell injury in vitro. Methods Thermal gradient was set in culturing IEC-6 cells in vitro. After thermal stimulation, Fluo-3Am probe with fluorescence microscope or flow cytometry was used to detect the change in intracellular Ca2+ concentration of IEC-6 cells. Phase contrast microscope was used to observe the morphological change in IEC-6. Coomassie blue dying method was employed to test the change in IEC-6 cytoskeleton. CCK-8 assay was used to assess cellular viability. Adhesion assay was applied to test the change in basilar membrane adhesiveness of IEC-6 cells. Results Compared with normal control group, cells of heat stress groups showed a thermal-dependent increase in intracellular Ca2+ concentration (P<0.01). Cells of heat stress groups were rounded in shape, the pseudopod was shorter, and cell space was enlarged. These phenomena were more obvious in 45℃ culture than in that of 43℃. Coomassie blue dying showed that the cytoskeleton of cells in heat stress groups became thickened and disordered, and stress fibers appeared. These phenomena were also more obvious in 45℃ culture than in that of 43℃. A thermal-dependant decline of cell viability in heat stress groups was observed via CCK-8 assay (P<0.01), and a thermal-dependant decline of basilar membrane adhesiveness in heat stress groups was observed via adhesion assay (P<0.01). Conclusion Heat stress may cause calcium overload of IEC-6 cells, and thus resulting in a series of calcium overload-related cell injury. Further investigation of the effect and mechanism of heat stress on calcium overload of intestinal mucosa endothelial cells may help further understand the mechanism of the pathogenesis of heat stroke.
A Video Denoising Method Based on Grouping the Similar Blocks and Surfacelet
Peng Geng,Li Xianbin,Yu Wanhai,Yan Shiqiang
Research Journal of Applied Sciences, Engineering and Technology , 2011,
Abstract: In this study, a novel video denoising method combining similar block matching based on the PDS searching method, grouping these similar block strategy and Surfacelet transform is proposed. Firstly, we apply the SAD block matching criterion and PDS search algorithm which we proposed by searching all frames for blocks which are similar to the currently processed one. In the complex motion case, the method of PDS can effectively decrease the number of search points and search number. Secondly, the matched blocks are put together to stack into some new third dimension sub-video sequences and because of the similarity between them, the data in the video array exists high level of correlation. We apply the surfacelet transform to them and effectively attenuate the noise by solid threshold shrinkage of the coefficients. Finally, inversely transforming the coefficients and obtaining the denoising video according to the obtained locations in the block matching process. This algorithm is obviously better than other 3D Curvlet and 3D wavelet method in the denoising effect and the PSNR is increased about 0.6dB. In terms of visual quality, the proposed method can effectively preserve the video detail, and the trajectory of motion object is very smooth, which is especially suitable to process the video flames with plenty of large area movement object or background change.
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