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Search Results: 1 - 10 of 104307 matches for " Guangfeng Zhang "
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Detective Method for Water Pollution Based on Millimeter Wave Radiant Characteristics  [PDF]
Beibei Li, Guangfeng Zhang, Guowei Lou, Luyan Zhou, Jing Liu
Journal of Computer and Communications (JCC) , 2016, DOI: 10.4236/jcc.2016.43013
Abstract:

Aim at monitoring water pollution, especially the aquatic vegetation, the multilayer dielectric model based on incoherent method is established to analysis the brightness temperature of aquatic vegetation. A 3 mm radiometer is used to measure the radiant characteristics of water pollution. Compared to 3 layer dielectric model, the simulation result of multilayer dielectric model is in better accordance with the experimental data, which shows that the multilayer dielectric model can model aquatic vegetation’s radiant characteristics more precisely. This result shows that water has millimeter wave radiant characteristics of low brightness temperature, cold target compared to aquatic vegetation. Based on the study of water’s brightness temperatures and aquatic vegetation’s radiant characteristics, the radiant characteristics can be used to monitor aquatic vegetation.

Exchange Rate Determination and Forecasting: Can the Microstructure Approach Rescue Us from the Exchange Rate Disparity?
Guangfeng Zhang,Qiong Zhang,Muhammad Tariq Majeed
ISRN Economics , 2013, DOI: 10.1155/2013/724259
Abstract: Using two measures of private information and high-frequency transaction data from the leading interdealer electronic broking system Reuters D2000-2, we examine the association between exchange rate return and contemporaneous order flow and the predictability power of lagged order flow on the future exchange rate return. Our empirical analysis demonstrates that at high frequency (5, 10, 15, 20, 25, and 30?min) there exists strong positive association between exchange rate returns and contemporaneous order flow. However, the results indicate weak predictability of order flow on the future exchange rate return. 1. Introduction In exchange rate economics one conventional common sense about exchange rates is that exchange rates follow a random walk process for frequencies less than annual, such as daily, weekly, or even monthly. However, exchange rates show some trend, cyclicality, or general history dependence at lower frequencies. In contrast to macroeconomic fundamental analysis at lower frequencies, studies on microstructure approaches to exchange rates focus on the movements in exchange rates at high frequency. In particular, microstructure approaches emphasize how exchange rates respond to order flow, which measures the net transaction pressure between buy and sell forces in the actual FX market. The theoretical frameworks for microstructure approaches to exchange rates have been sequentially built by Lyons [1] and Evans and Lyons [2]. In particular, the portfolio-shift model proposed by Evans and Lyons [2] is initially set up in a customer-dealer trading environment to show how order flow impacts exchange rates. Evans and Lyons apply the trading model to daily data obtained from the customer-dealer transaction platform Reuters D2000-1 to examine the exchange rate Deutsche mark/US dollar and Japanese yen/US dollar over May 1 to August 31, 1996. As a result, Evans and Lyons find that order flow can be a good series to determine the exchange rate movement at daily frequency. Similarly, empirical studies have applied this theoretical framework to various high-frequency data from diverse interdealer trading platforms. Killeen et al. [3] study the daily exchange rate German mark/French franc traded on the electronic broking system (EBS) in 1998. Hau et al. [4] study EBS data over 1998 to 1999 on the exchange rate German mark against US dollar. Berger et al. [5] study the intraday EBS data on the exchange rate US dollar/Japanese yen and Euro/US dollar spanning over January 1999 to February 2004. Ito and Hashimoto [6] study the intraday EBS data on the
Complement Activity in the Egg Cytosol of Zebrafish Danio rerio: Evidence for the Defense Role of Maternal Complement Components
Zhiping Wang, Shicui Zhang, Guangfeng Wang, Yan An
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001463
Abstract: Most fish embryos that develop externally are exposed to an environment full of microbes. How they survive microbial attacks are not understood to date. Here we demonstrated that the egg cytosol prepared from the newly fertilized eggs of zebrafish Danio rerio is capable of killing the Gram-negative bacterium Escherichia coli, via in vitro assay system of the complement activity established. All findings indicate that it is the complement system operating via the alternative pathway that is attributable to the bacteriolytic activity. This is the first report providing the evidence for the functional role of the maternal complement components in fish eggs, paving the way for study of maternal immunity in other organisms whose eggs are fertilized in vitro.
Maternal Transfer and Protective Role of the Alternative Complement Components in Zebrafish Danio rerio
Zhiping Wang, Shicui Zhang, Zhou Tong, Lei Li, Guangfeng Wang
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0004498
Abstract: Embryos of most fish develop externally and are exposed to an aquatic environment full of potential pathogens, whereas they have little or only limited ability to mount an efficient and protective response. How fish embryos survive pathogenic attacks remains poorly defined. Here we demonstrate that the maternal immunization of female zebrafish with formalin-killed Aeromonas hydrophila causes a significant increase in C3 and Bf contents in the mother, a corresponding rise in the offspring, and induces a remarkable increase in the hemolytic activities in both the mother and offspring. In addition, the embryos derived from the immunized mother are significantly more tolerant to A. hydrophila challenge than those from the unimmunized fish, and blocking C3 and Bf activities by injection of the antibodies against C3 and Bf into the embryos render them more susceptible to A. hydrophila. These results clearly show that the protection of zebrafish embryos against A. hydrophila can be achieved by the maternally-transferred immunity of the complement system operating via the alternative pathway. This appears to be the first report providing in vivo evidences for the protective role of the alternative complement components in the early embryos of zebrafish, paving the way for insights into the in vivo function of other maternally-transferred factors in fish.
A formula for Euler characteristic of line singularities on singular spaces
Guangfeng Jiang
Mathematics , 2000,
Abstract: We prove an algebraic formula for the Euler characteristic of the Milnor fibres of functions with critical locus a smooth curve on a space which is a weighted homogeneous complete intersection with isolated singularity.
Conormal modules via Primitive ideals
Guangfeng Jiang
Mathematics , 2000,
Abstract: The main object of this note is to study the conormal module $M$ and the computation of the second symbolic power $\bar I^{(2)}$ of an ideal $\bar I$ in the residue ring $R/H$ of a polynomial ring $R$ over a field of characteristic zero. The torsion part $T(M)$ of $M$ and the torsion free module $M/T(M)$ are expressed by the primitive ideal of $I$ relative to $H$. Two characterizations for $M/T(M)$ to be free are proved. Some immediate applications are worked out.
Rapamycin Attenuates Endothelial Apoptosis Induced by Low Shear Stress via mTOR and Sestrin1 Related Redox Regulation
Junxia Zhang,Zhimei Wang,Junjie Zhang,Guangfeng Zuo,Bing Li,Wenxing Mao,Shaoliang Chen
Mediators of Inflammation , 2014, DOI: 10.1155/2014/769608
Abstract: Background. Studies indicate the dramatic reduction of shear stress (SS) within the rapamycin eluting stent (RES) segment of coronary arteries. It remains unclear about the role of rapamycin in endothelialization of stented arteries where SS becomes low. Since mTOR (mammalian target of rapamycin) pathway is involved in the antioxidative sestrins expression, we hypothesized that rapamycin attenuated low SS (LSS) induced endothelial dysfunction through mTOR and sestrin1 associated redox regulation. Methods and Results. To mimic the effect of LSS on the stented arteries, a parallel plate flow chamber was used to observe the interplay of LSS and rapamycin on endothelial cells (ECs). The results showed LSS significantly induced EC apoptosis which was mitigated by pretreatment of rapamycin. Rapamycin attenuated LSS induced reactive oxygen species (ROS) and reactive nitrogen species (RNS) production via prohibition of sestrin1 downregulation. Activities of mTORC1 and mTORC2 were detected contradictorily modulated by LSS. Inhibition of rictor expression by target small interfering RNA (siRNA) transfection prohibited sestrin1 downregulation induced by LSS, but inhibition of raptor did not. Conclusions. Rapamycin may prohibit sestrin1 downregulation through targeting mTORC2 in appeasing LSS induced EC oxidative apoptosis. Our results provide the in vitro evidence to explain the pathophysiology of RES stented arteries. 1. Introduction Rapamycin, the specific inhibitor of mTOR (mammalian target of rapamycin), is a natural product of the soil actinomycete streptomyces hygroscopicus [1]. Rapamycin and its derivatives are widely employed in the rapamycin eluting stent (RES) because they successfully prevent in-stent restenosis [2]. However, rapamycin is suspected to compromise endothelial function and induce endothelial apoptosis [3] and even implicate to delayed endothelialization [4–7]. Conversely, other researchers found rapamycin was not such cytotoxic to ECs as it arrested ECs at G0/G1 phase of cell cycle without inducing apoptosis [8]. Furthermore, rapamycin was reported to attenuate high-amplitude, mechanical stretch-induced apoptosis in pulmonary microvascular endothelial cells [9]. Therefore, the potential of rapamycin on EC apoptosis needs to be clarified. Low shear stress (LSS) is a well-established risk factor resulting in endothelial dysfunction and atherosclerotic lesions [10, 11]. Data from our previous in vivo studies demonstrated that SS on the luminal surface of stented coronary artery reduced dramatically after implantation of RES [12, 13]. In the
Quantitative Analysis of Dynamic Behaviours of Rural Areas at Provincial Level Using Public Data of Gross Domestic Product
Yi Chen,Guangfeng Zhang,Yiyang Li,Yi Ding,Bin Zheng,Qiang Miao
Entropy , 2013, DOI: 10.3390/e15010010
Abstract: A spatial approach that incorporates three economic components and one environmental factor has been developed to evaluate the dynamic behaviours of the rural areas at a provincial level. An artificial fish swarm algorithm with variable population size (AFSAVP) is proposed for the spatial problem. A functional region affecting index θ is employed as a fitness function for the AFSAVP driven optimisation, in which a gross domestic product (GDP) based method is utilised to estimate the CO2 emission of all provinces. A simulation for the administrative provinces of China has been implemented, and the results have shown that the modelling method based on GDP data can assess the spatial dynamic behaviours and can be taken as an operational tool for the policy planners.
Mono-dispersed Functional Polymeric Nanocapsules with Multi-lacuna via Soapless Microemulsion Polymerization with Spindle-like α-Fe2O3Nanoparticles as Templates
Liu Guangfeng,Liu Peng
Nanoscale Research Letters , 2009,
Abstract: The mono-dispersed crosslinked polymeric multi-lacuna nanocapsules (CP(St–OA) nanocapsules) about 40 nm with carboxylic groups on their inner and outer surfaces were fabricated in the present work. The small conglomerations of the oleic acid modified spindle-like α-Fe2O3nanoparticles (OA–Fe2O3) were encapsulated in the facile microemulsion polymerization with styrene (St) as monomer and divinyl benzene (DVB) as crosslinker. Then the templates, small conglomerations of OA–Fe2O3, were etched with HCl in tetrahydrofuran (THF). The surface carboxylic groups of the crosslinked polymeric multi-lacuna nanocapsules were validated by the Zeta potential analysis.
Measurement Model on Human Capital Cost of Enterprise
guangfeng Ye,xia Zhou
International Business and Management , 2012, DOI: 10.3968/j.ibm.1923842820120502.z0961
Abstract: This study of human capital of enterprises and human capital cost receives more and more attention from both the academic and business circles. But still there lacks mature methods to measure human capital cost. Based on relevant research results on human capital, the paper provided on how to calculate the human capital investment, how to control the amount of investment and how to optimize the investment structure. key words: Human capital cost; Measurement model
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