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Search Results: 1 - 10 of 27675 matches for " Weibin Hu "
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Corporate Governance, Financial Constraint, and Value of Cash Holdings: Research from the Perspective of Ultimate Controllers  [PDF]
Weibin Zhao
Modern Economy (ME) , 2016, DOI: 10.4236/me.2016.710111
Abstract: This paper takes into consideration the character of China as an emerging market and distinguishes between the ultimate-controller trait of the central government and the local government. This paper conducts the analysis using the corporate governance and financial character perspectives, based on agency theory and financial constraint theory. The findings show that corporate governance is the main reason for values of cash holdings of SOEs are lower than those of private firms. Moreover, values of cash holdings of SOEs controlled by the central government are higher than those of cash holdings of firms controlled by local governments. The difference could be attributed to the observation that central government-controlled SOEs have better governance and investment opportunities compared with the local government-controlled ones. The objectives of this paper are to determine the factors influencing the difference between cash holdings of state-owned enterprises (SOEs) and private firms, and to analyze the influence of governments at different levels on value of cash holdings of SOEs in China. Results of the analysis are expected to aid in understanding of how corporate governance and financial constraint affect value of cash holdings of firms.
Discussion on several indices assessing landscape dispersion
几种景观分离程度评价指标的探讨

JIN Weibin,HU Bingmin,
金卫斌
,胡秉民

应用生态学报 , 2003,
Abstract: Several indices assessing landscape dispersion, such as isolation, type divergence and nearest neighbor index, were compared. Different indices could reflect different aspects of landscape dispersion. Dispersion index was suggested to assess the dispersion more comprehensively. All the indices were computed to study the landscape dispersion in a valley basin, and the results showed that dispersion index was better to synthesize information and to be in line with practice than others.
Investigation and Evaluation on Heavy Metal Copper and Cadmium Contaminations of Vegetables Grown in Huanggang City of China
Xiaoming Hu,Weibin Jin,Wenjuan Lv,Shuiyuan Cheng
Advance Journal of Food Science and Technology , 2013,
Abstract: No published data are available on heavy metals concentrations and contaminations of vegetables in Huanggang City, Hubei Province, China. This study focused on characteristics and evaluation on heavy metal (Copper and Cadmium) concentrations and contaminations in vegetables grown in the suburbs of Huanggang. Several important vegetable bases in the suburbs of the city were employed as study areas and 150 representative vegetable samples, including leaf vegetables, melon-fruit vegetables, root-stem vegetables, bean vegetables and melon-fruit vegetables, were collected to determine the contents of heavy metal Copper (Cu) and Cadmium (Cd) using Atomic Absorption Spectrophotometer (Varian, AA240FS, USA). The status of Cu and Cd concentrations and contaminations were analyzed and evaluated according to Chinese Food and Health National Standard. The results indicated that nearly all vegetable in Huanggang City were highly contaminated by Cd. And Cu contamination occurred in leafy vegetables and some melon-fruit vegetables and bean vegetables were not found contaminated by Cu. The contamination degree of Cd was much higher than that of Cu. Vegetable Cd contamination has posed a threat to the people in the city and will hinder the sustainable development of the local vegetable industry. It is strongly recommended that the local government of Huanggang City should pay much more attention to the vegetable Cd contamination in the city. Why heavy metal Cd polluted seriously and how to prevent it in the city need to be further studied.
Numerical Simulation of Wind Field Characteristics around Two Adjacent High-Rise Buildings  [PDF]
Wenkai He, Weibin Yuan
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.26031
Abstract:

This paper based on Reynolds-averaged Navier-Stokes equations standard  model [1]; the surface pressure on the wind field around two adjacent high-rise buildings was numerically simulated with software Fluent. The results show that with the influence of adjacent high-rise building, numerical simulation is a good way to study the wind field around high-rise building and the distribution of wind pressure on building’ surface. The pressures on the windward surface are positive with the maximum at 2/3 H height and have lower values on the top and bottom. The pressures on the leeward surface and two sides were negative. Due to the serious flow separation at the corner of building’s windward, the wind field has a high turbulent kinetic energy.

Directly determining the relative phase of two coherent solitary waves in attractive Bose-Einstein condensates
Weibin Li
Physics , 2008,
Abstract: We study the dynamic structure factor of two coherent bright solitary waves in attractive Bose- Einstein condensates confined in a harmonic trap. We demonstrate that the wave function of the two solitary waves with a fixed relative phase shows interference in momentum space. The fringes are shifted depending on the values of the phase. This momentum interference can be extracted from the dynamic structure factor of the system using stimulated two-photon Bragg scattering. Thus our method provides a way to measure the relative phase directly.
Efficient induction of CD25- iTreg by co-immunization requires strongly antigenic epitopes for T cells
Shuang Geng, Yang Yu, Youmin Kang, George Pavlakis, Huali Jin, Jinyao Li, Yanxin Hu, Weibin Hu, Shuang Wang, Bin Wang
BMC Immunology , 2011, DOI: 10.1186/1471-2172-12-27
Abstract: In the present study, we demonstrated the requirement of highly antigenic epitopes for CD25- iTreg induction. Firstly, we showed that the induction of CD25- iTreg by tolerogenic DC can be blocked by anti-MHC-II antibody. Next, both the number and the suppressive activity of CD25- iTreg correlated positively with the overt antigenicity of an epitope to activate T cells. Finally, in a mouse model of dermatitis, highly antigenic epitopes derived from a flea allergen not only induced more CD25- iTreg, but also more effectively prevented allergenic reaction to the allergen than did weakly antigenic epitopes.Our data thus indicate that efficient induction of CD25- iTreg requires highly antigenic peptide epitopes. This finding suggests that highly antigenic epitopes should be used for efficient induction of CD25- iTreg for clinical applications such as flea allergic dermatitis.The inducible regulatory T cells, or iTreg, differ from the naturally regulatory T cells (nTreg) in that the former are generated in the periphery through encounter with environmental antigens. It is also believed that iTreg play non-overlapping roles, relative to nTreg, in regulating peripheral tolerance [1-3]. Most iTreg reported to date have been CD25+ cells (CD4+CD25+Foxp3+), and it is well established that their induction requires suboptimal stimulation of the T cell receptor (TCR) and cytokines TGF-β and IL-2 [3]. The CD25+ iTreg thus appear to derive primarily from weakly stimulated CD4+ T cells.We previously identified a different subset of iTreg in mice that is CD25- (CD4+CD25-Foxp3+ and IL-10+TGF-beta+IFN-γ-). The CD25- iTreg were induced after co-immunization using a protein antigen and a DNA vaccine encoding the same antigen [4-7]. Unlike that of the CD25+ iTreg, the induction of the CD25- iTreg involved the generation of CD40low IL-10high tolerogenic dendritic cells (DCs), which in turn stimulated CD25- iTreg in an antigen-specific manner [4]. We further showed in mouse models that this
Ovicidal activity of two fungal pathogens (Hyphomycetes) againstTetranychus cinnabarinus (Acarina: Tetranichidae)
Weibin Shi,Mingguang Feng
Chinese Science Bulletin , 2004, DOI: 10.1007/BF03182810
Abstract: The carmine spider mite,Tetranychus cinnabarinus, is an economically important pest that devastates varieties of crops worldwide and develops significant resistance to common chemical pesticides, most of which lack ovicidal activity. In the present study, two isolates of entomopathogenic fungi,Beuaveria bassiana SG8702 andPaecilomyces fumosoroseus Pfr153, were bioassayed againstT. cinnabarinus eggs at 25 °C under a photophase of 12:12 (L:D). Infected eggs onVicia faba var.minor leaves failed to hatch due to distortion and shrinkage and had fungal outgrowths when maintained under moist conditions. Sprays ofB. bassiana conidia toT. cinnabarinus eggs (on leaves) at the concentrations of 58, 298 and 1306 conidia/mm2 (3 replicates per concentration and 35–65 fresh mite eggs per replicate) resulted in corrected egg mortalities of 20.4±4.2%, 36.0±7.6% and 64.6±12.5% (F=43.14,P <0.01), respectively; sprays ofP. fumosoroseus at 129, 402 and 2328 conidia/mm2 caused egg mortalities of 16.1±11.1%, 44.2±13.3%, and 63.4±11.7% (F= 15.37, P=0.01), respectively. In contrast, natural egg mortalities in blank controls were 7.8% and 10.3% only. Based on probit analysis, the estimates of LC50 with 95% confidential limits were 548 (393–858) conidia/mm2 forB. bassiana and 914 (625–1550) forP. fumosoroseus, respectively. Apparently, both fungal species were capable of infectingT. cinnabarinus eggs, but the ovicidal activity of theB. bassiana isolate was greater than that of theP. fumosoroseus isolate. This represents the first report on the ovicidal activity of the two entomopathogenic Hyphomycetes againstT. cinnabarinus.
Highly controllable ICP etching of GaAs based materials for grating fabrication

Qiu Weibin,

半导体学报 , 2012,
Abstract:
A STEREO-ETCHING FOR OBSERVATION OF DEFECTS IN HEAVILY Te-DOPED GaAs CRYSTAL

GAO Weibin,

金属学报 , 1984,
Abstract: The defects in the heavily Te-doped GaAs crystals were observed under optical microscope using A/B etchant. It showed that the distance from the dislocation line to metallographic etched surface may be qualitatively ascertained on the basis of the etched figure on the specimen surface. Thus, to make an approach to concept of "stereo-etching" was tried and its principle was also discussed. After observation on the helicoidal dislocation and boat pit by means of "stereo-etching", it was confirmed that a boat pit is in correspondence with either one pitch of helicoidal dislocation or an individual dislocation loop.
Characteristic analysis on an interleaver with a fiber loop resonator by using a signal flow graph method
Weibin Li,Junqiang Sun
Optica Applicata , 2008,
Abstract: We propose an interleaver based on the Mach–Zehnder interferometer with a resonator incorporated in one arm. By using the method of signal flow graph, we get the simple closed-form expressions for transmission of this interleaver. The result indicates that the widths of 0.5 dB passband and 25 dB stopband of the interleaver are improved remarkably, which are much wider than that of the conventional Mach–Zehnder interferometer. The interleaver proposed has an ideal rectangular spectral response. Finally, we have analyzed the influence exerted by the parameters on its transimission characteristics and found that the transmission spectrum of this device depends highly on the intensity coupling coefficient of the coupler and fiber loop length.
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