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Systems Science and Systems Engineering 1999年第2期9卷 129-139页

作者： XIE Zhendong(Department of Automation, Sollth China university of TeChnology, guangzhou 510640, prc)TIAN Senping(Department of Industrial Equipment and Control EngilleeTing, South Chilla University ofTechnologyl guangzhou 510640, prc)LIU Yongqing(Departm

The existence and stability of positive periodic solution of delay logistic ecosystem withfeedback control and diffusion have been discussed in this paper. By using the methods of upper andlower solutions, Brouwer’s ... 详细信息

关键词： delay logistic ecosystem solution feedback control diffusion existence stability

Water pricing towards sustainability of water resources: a case study in Beijing

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Journal of Environmental Sciences 2002年第4期14卷 518-523页

作者： LIU Shao (guangzhou Research Institute of Environmental Protection, guangzhou 510620, China. ) guangzhou Heseureh Institute of Environmental Protection Guangzhou 510620

The role of water pricing for managing water resources is widely recognized in many areas of the world because of the increasing scarcity of water resources, a high competition between water uses and environmental degradation. Based on the analysis of cost of water, this paper explores which types of cost should be reflected in the water pricing enhancing the sustainability of water resources. The principle of full cost pricing in which the cost should include supply cost, opportunity cost and externalities is proposed as a means to achieve the sustainability of water resources. In a case study of Beijing, low water price is analyzed as one reason for unsustainable water consumption. Thus water pricing justified is necessary and pressing. It is proposed to justify water price in phased manner and eventually towards full cost pricing. The assessment of impacts on water resources by raising water price shows water pricing could alleviate the conflict between water supply and demand. This paper concludes that water pricing can play an effective role in enhancing the sustainability of water resources in Beijing.

关键词： water resources water price cost full cost pricing sustainability Beijing

Roles of urban vegetation on balance of carbon and oxygen in guangzhou, China

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Journal of Environmental Sciences 2003年第2期15卷 155-159页

作者： GUAN Dong-sheng, CHEN Yu-juan (Department of Environmental Science, Zhongshan University, guangzhou 510275, China. Department of Environmental Science Zhongshan University Guangzhou 510275 China

The plant biomass and net primary production(NPP) of urban vegetation in guangzhou were estimated by dimension analysis, tree truck volume, and harvest methods as well as relationship between biomass and NPP and so on. The biomass and NPP were respectively 2875150t and 1058122 t/a. They were respectively 392495t and 64948 t/a in the built-up area and 2482655t and 993147 t/a in the unbuilt-up area. It would make plant biomass, especially NPP decline obviously, if the unbuilt-up area were changed to the built-up area. The carbon content of plant was 1328649 for the total and 13.78 t/hm 2 for the mean, and amounts of carbon fixed and oxygen made by urban vegetation were respectively 4.80 t/(hm 2·a) and 12.79 t/(hm 2·a) for the mean and 462624 t/a and 1232430 t/a for the total, which were equal to 1.45 times and 1.04 times of those by human breathing. However, they were only equal to 7.61% and 4.97% of amount of carbon released and oxygen consumption in urban guangzhou. The biomass and NPP of urban vegetation in guangzhou only corresponded to 7.8% and 47.3% of those of southern subtropical evergreen broad-leaf forest in Dinghu Mountain. Therefore, the roles of guangzhou urban vegetation in balance of carbon and oxygen would be increased greatly if it could be conserved and improved in some way.

关键词： urban vegetation carbon oxygen balance guangzhou

Entropy correction of BTZ black holes in a tunneling framework

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Science China(Physics,Mechanics & Astronomy) 2010年第8期53卷 1427-1433页

作者： ZHANG JingYi Center for Astrophysics, guangzhou University, guangzhou 510006, China 1. Center for Astrophysics Guangzhou University Guangzhou 510006 China

In this paper, using the Parikh-Wilczek tunneling framework, we first calculate the emission rates of non-rotating BTZ black holes and rotating BTZ black holes to second order accuracy. Then, by assuming that the emission process satisfies an underlying unitary theory, we obtain the corrected entropy of the BTZ black holes. A log term emerges naturally in the expression of the corrected entropy. A discussion about the inverse area term is also presented.

关键词： Hawking radiation black hole tunneling black hole entropy correction quantum theory

ELECTRON THEORY OF THERMAL EXPANSION FOR RARE EARTH METALS WITH hcp STRUCTURE

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Chinese Science Bulletin 1989年第21期34卷 1769-1772页

作者：万纾民 Solid and Molecular Research Group Jinan University Guangzhou 510080 PRC

I. INTRODUCTION In Ref. [1], the author has set up the electron theory of thermal expansion in solids and applied it to some light metals with more satisfactory results. The present note tries

关键词： electron theory thermal expansion rare earth metals hep structure

DETERMINANTS OF REAL QUATERNION MATRICES

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Numerical Mathematics A Journal of Chinese Universities(English Series) 2000年第S1期9卷 53-58页

作者： Li Yangming(Dept.of Math.,Educational college of Guangdong,guangzhou 510303,prc/Dept.of Math,Zhongshan University,guangzhou 510275,prc)

Let Q be the real quaternion *** the set of all matrices A=(αij)n×mbe Qn×mwhere αij∈Q,A+ be the conjugate transpose of *** a long period of time,there have been various kinds of definitions of determinantover the real quaternion field,but all of them are not concerning the entries of thematrix directly,that is"undirectly".From the point of view how the theory of determi-nant is algebraically developed for skew field,it may be worthwhile defined

关键词： Math DETERMINANTS OF REAL QUATERNION MATRICES over Chen real

Effects of Dielectric Barrier Discharge Plasma Treatment on Pentachlorophenol Removal of Granular Activated Carbon

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Plasma Science and Technology 2013年第10期15卷 1059-1065页

作者： JI Puhui QU guangzhou LI Jie College of Resources and Environment Northwest Agriculture and Forestry UniversityYangling 712100 China Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China Ministry of Agriculture Yangling 712100 China Key Laboratory of Industrial Ecology and Environmental Engineering Ministry of Education Dalian 116024 China

The pentachlorophenol （PCP） adsorbed granular activated carbon （GAC） was treated by dielectric barrier discharge （DBD） plasma. The effects of DBD plasma on the structure of GAC and PCP decomposition were analyzed by N2 adsorption, thermogravimetric, scanning electron microscopy （SEM）, X-ray photoelectron spectroscopy （XPS） and gas chromatographymass spectrometry （GC-MS）. The experimental data of adsorption kinetics and thermodynamics of PCP on GAC were fitted with different kinetics and isotherm models, respectively. The results indicate that the types of N2 adsorption isotherm of GAC are not changed by DBD plasma, while the specific surface area and pore volume increase after DBD plasma treatment. It is found that the weight loss of the saturated GAC is the highest, on the contrary, the weight loss of DBD treated GAC is the least because of reduced PCP residue on the GAC. The XPS spectra and SEM image suggest that some PCP on the GAC is removed by DBD plasma, and the surface of GAC treated by DBD plasma presents irregular and heterogeneous morphology. The GC-MS identification of by-products shows that two main dechlorination intermediate products, tetrachlorophenol and trichlorophenol, are distinguished. The fitting results of experimental data of adsorption kinetics and thermodynamics indicate that the pseudo-first-order and pseudo-second order models can be used for the prediction of the kinetics of virgin GAC and DBD treated GAC for PCP adsorption, and the Langmuir isotherm model fits better with the data of adsorption isotherm than the Freundlich isotherm in the adsorption of PCP on virgin GAC and DBD treated GAC.

关键词： granular activated carbon dielectric barrier discharge plasma adsorption pentachlorophenol decomposition

Chandra observations of the H_2O megamaser galaxy Mrk1210

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Science China(Physics,Mechanics & Astronomy) 2009年第6期52卷 960-968页

作者： ZHANG JiangShui & FAN JunHui Center for Astrophysics, guangzhou University, guangzhou 510006, China Center for Astrophysics Guangzhou University Guangzhou 510006 China

We present the first Chandra X-ray observations of the H2O megamaser galaxy Mrk1210 (UGC4203), a Seyfert 2 galaxy at an approximate distance of D～57.6 Mpc. The Chandra X-ray image, with by far the highest angular resolution (～1"), displays an unresolved compact core toward the nuclear region of Mrk1210. Comparisons with the previous X-ray observations in the nuclear emission and the spectral shape indicate a fairly stable phase between 2001 (BeppoSAX and XMM-Newton) and 2004 (Chandra) after a dramatic variation since 1995 (ASCA). The best-fit model of Chandra X-ray spectrum consists of two components. The soft scattered component can be best fitted by a moderately absorbed power-law model adding a spectral line at ～0.9 keV (possibly a Ne-Kα fluorescent line), while the hard nuclear component can be well reproduced by a heavily absorbed power-law model (NH～2×1023 cm-2) with an additional line at ～6.19 keV (close to the Fe-Kα fluorescent line). The derived absorption-corrected X-ray luminosity implies that the dramatic variation of spectral properties is caused by significant changes of the absorbing column density along the line-of-sight, while the intrinsic nuclear X-ray lu-minosity remains stable. In this case, the absorbers should be anisotropic and its size can be constrained to be less than 0.0013 pc. In addition, we also estimate the mass of central engine, the disk radius and the accretion rate of the accretion disk to be 107.12±0.31M⊙, ～1 pc and 0.006, respectively.

关键词： active galaxy nuclei Seyfert galaxy X-ray maser

Three-Electron Quantum Dots in Zero Magnetic Field

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Communications in Theoretical Physics 2007年第12期48卷 1115-1118页

作者： XIE Wen-Fang Department of Physics,guangzhou University,guangzhou 510006,China Department of Physics Guangzhou University

By using the exact diagonalization method,a system of three electrons confined in a parabolic quantumdot in zero magnetic field is *** ground-state electronic structures and orbital and spin angular momentatransitions as a function of the confined strength are *** find that the confinement may cause accidentaldegeneracies between levels with different low-lying states and the inversion of the energy *** present,resultsare useful to understanding the optical properties and internal electron-electron correlations of quantum dot materials.

关键词： electron-electron interaction quantum dot semiconductor