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Ecological service assessment of human-dominated freshwater ecosystem with a case study in Yangzhou Prefecture, China

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Journal of Environmental Sciences 2004年第5期16卷 755-761页

作者： YEYa-ping WANGRu-song RENJing-ming HUDan YUANShao-jun WANGMin ResearchCenterforEco-EnvironmentalSciences ChineseAcademyofSciencesBeijing100085China

Freshwater ecosystems provide a host of services to humanity. These services are now rapidly being lost, not least because of the inability of making the impacts measurable. To overcome this obstacle, assessment frameworks for freshwater ecosystem services are needed. A simple water equivalent framework to assess the ecological services provided by freshwater ecosystems was developed in this study. It translated the occupation of freshwater ecosystem services into biologically freshwater volumes and then compares this consumption to the freshwater throughput, that is, the ecological capacity available in this region. In this way, we use the example of Yangzhou Prefecture, to account the main categories of human occupation of water ecosystem services. The result showed that there is a huge gap between the consumption and the supply of freshwater ecosystem services. This must encourage local government to make land-use and water management decisions both economically rational and environmentally sound.

关键词： freshwater ecosystems services human impacts assessment water equivalent Yangzhou Prefecture

Soil CO_2 flux in relation to dissolved organic carbon,soil temperature and moisture in a subtropical arable soil of China

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Journal of Environmental Sciences 2003年第5期15卷 715-720页

作者： LOUYun-sheng LIZhong-pei ZHANGTao-lin CollegeofNaturalResourcesandEnvironmentalSciences NanjingAgriculturalUniversityNanjing210095China InstituteofSoilScience ChineseAcademyofSciencesNanjing210008China

Soil CO 2 emission from an arable soil was measured by closed chamber method to quantify year round soil flux and to develop an equation to predict flux using soil temperature, dissolved organic carbon(DOC) and soil moisture content. Soil CO 2 flux, soil temperature, DOC and soil moisture content were determined on selected days during the experiment from August 1999 to July 2000, at the Ecological Station of Red Soil, the Chinese Academy of Sciences, in a subtropical region of China. Soil CO 2 fluxes were generally higher in summer and autumn than in winter and spring, and had a seasonal pattern more similar to soil temperature and DOC than soil moisture. The estimation was 2 23 kgCO 2/(m 2·a) for average annual soil CO 2 flux. Regressed separately, the reasons for soil flux variability were 86 6% from soil temperature, 58 8% from DOC, and 26 3% from soil moisture, respectively. Regressed jointly, a multiple equation was developed by the above three variables that explained approximately 85 2% of the flux variance, however by stepwise regression, soil temperature was the dominant affecting soil flux. Based on the exponential equation developed from soil temperature, the predicted annual flux was 2 49 kgCO 2/(m 2·a), and essentially equal to the measured one. It is suggested the exponential relationship between soil flux and soil temperature could be used for accurately predicting soil CO 2 flux from arable soil in subtropical regions of China.

关键词： soil CO 2 flux soil temperature DOC soil moisture arable soil

Molecular Structure of Bicyclopentadienyl (methycyclopentadienyl) Furanto Samarium

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Journal of Rare Earths 2004年第S1期22卷 51-53页

作者：刘太奇李静莉沈琪 Beijing Institute of Petro-Chemical Technology Beijing 102600 China Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China

The mixed tris-cyclopentadienyl tetrahydrofuranato samarium complexes bis-(cyclopentadienyl) methylcyclopentadienyl tetrahadrofuranato samarium (Ⅰ) was synthesized by reaction of (C_5H_5)_2SmCl with methyl cyclopentadienyl sodium in THF. [(C_5H_5)_2(C_5H_4CH_3)(C_4H_8O)Sm] (Ⅰ) was characterized by elemental analyses, IR spectra and MS spectra. The structure of [(C_5H_5)_2(C_5H_4CH_3)(C_4H_8O)Sm] (Ⅰ), which has two slightly different independent molecules per asymmetric unit, was elucidated through complete X-ray analysis. The crystals are monoclinic with a=1.2791(3) nm, (b=1.0467(2) nm,) c=2.6108(5) nm, β=98.22(2)°, space group Cc, R=0.0381 for 2103 observed reflection with I3σ(I).

关键词： samarium complex cyclopentadienyl molecular structure rare earths

The Reaction of Octacarbonyldicobalt and Dipropargyl Malonate

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Chinese Journal of Structural Chemistry 2001年第2期20卷 104-107页

作者：张玉华劳文剑罗资琴殷元骐黄子祥吴锵金 Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou Petro-chemical College of Technology Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences

The reaction of octacarbonyldicobalt and dipropargyl malonate afforded the two expected compounds [CH 2(CO 2CH 2C 2H\|μ) 2][Co 2(CO) 6] 2 1 and [HC 2CH 2O(O)C^CH 2CO 2CH 2C 2H\|μ][Co 2(CO) 6)] 2. Both 1 and 2 were characterized by elemental analysis, IR and NMR. The molecular structure of 1 was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with the following crystallographic parameters~: a=7.7492(15), b=12.925(3), c=14.366(3) , α=81.92(3), β=77.94(3), γ=89.48(3)°, V=1392.9(5)  3, Z= 2, M r=751.99, D c=1.793 g/cm 3, F(000)=740, μ(Mo-Kα)=24.13 cm -1 and final R=0.0880 for 5421 observations with I>2σ(I).

关键词： cobalt alkyne carbonyl crystal structure

Investigation of natural VOC emitted from tropical vegetations in China

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Journal of Environmental Sciences 2005年第1期17卷 8-13页

作者： WANGZhi-hui BAIYu-hua LIUZhao-rong WANGXue-song LIQing-junt L.F.Klinger CollegeofEnvironmentalSciences PekingUniversityBeijing100871China XishuangbannaTropicalBotanicalGarden ChineseAcademyofSciencesKunming650223China InstituteofNoeticSciences 101SanAntonioRoadPetalumaCA94952USA

Twenty three kinds of typical plants in Xishuangbanna, the tropical area of southwestern China, were screened to estimate the emission rates of isoprene and monoterpenes by adopting bag enclosure and curette sampling methods followed by a GC FID analysis. It was found that the Ficus species were mainly emitting isoprene and most tropical vegetations were mainly releasing monoterpenes. The results also showed that the emissions of isoprene were affected by both temperature and PAR(Photosynthetic Active Radiation), while monoterpene emissions were mainly temperature dependent.

关键词： VOC isoprene monoterpenes emission factor Xishuangbanna

An investigation of cellular distribution of manganese in hyperaccumlator plant Phytolacca acinosa Roxb. using SRXRF analysis

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Journal of Environmental Sciences 2006年第4期18卷 746-751页

作者： XU Xiang-hua SHI Ji-yan CHEN Ying-xu XUE Sheng-guo WU Bei HUANG Yu-ying Department of Environmental Engineering Zhejiang University Hangzhou 310029 China Institute of High Energy Physics Chinese Academy of Sciences Beijing 100039 China

Phytolacca acinosa Roxb. （P acinosa） is a recently discovered manganese hyperaccumulator plant from southern China. It is a good candidate for phytoremediation of manganese（Mn） polluted soil for its high biomass and fast growth. Knowledge of the tissue localization and identification of heavy metals can provide essential information on metal toxicity and bioaccumulation mechanisms. Synchrotron radiation X-ray fluorescence spectroscopy （SRXRF） microprobe was used in this study to investigate the cellular distributions of Mn and other elements in root, stem, leaf, petiole and midrib of P. acinosa. The highest Mn content was found in the vascular tissues of root, stem, petiole and midrib. Cortex in root played a key role in Mn absorption and Mn was limited in the vascular bundle during the process of transportation in stem. Moreover, Mn content in leaf epidermis was higher than that in mesophyll, which suggested that the sequestration of Mn in leaf epidermis might be one of the detoxification mechanisms of P. acinosa. The significance of other elemental （such as P, S, K, Ca, Fe, Zn and Cu） distribution patterns and the correlation with Mn were also discussed.

关键词： hyperaccumulator Phytolacca acinosa Roxb. manganese element distribution SRXRF

Effect of nitrogen and phosphorus on the water quality in the Three Gorges Reservoir Area during and after its construction

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Journal of Environmental Sciences 2004年第3期16卷 358-363页

作者： LIUHong LIUHui-juan QUJiu-hui StateKeyLaboratoryofEnvironmentalAquaticChemistry ResearchCenterforEco-EnvironmentalSciencesChineseAcademyofSciences.Beijing100085.China

A survey concerning the concentration of the nutrients in the Three Gorges Reservoir Area was carried out. This paper presents the parameters(NO 3 - N, NO 2 - N, Kjeldahl N, non ionic ammonia, P PO 4 and TP) determined at 16 sampling sites from 1997 to 1999 The dominant soluble nitrogen form was NO 3 - N followed by Kjeldahl N, NO 2 - N and non ionic ammonia. Mean values of NO 3 - N, NO 2 - N, Kjeldahl N and non ionic ammonia ranged from 0 50 to 2 37 mg/L, 0 022 to 0 084 mg/L, 0 33 to 0 99 mg/L and 0 007 to 0 092 mg/L respectively. Mean values of P PO 4 at most sampling sites were higher than 0 1 mg/L for subject to eutrophication. The major factors influencing the concentrations of N and P might be agricultural runoff, municipal and industrial effluents. In addition, 6 kinds of soil were sampled at the area where would inundated after the dam completed. Two approaches were adopted to simulate the N and P release from the inundated soils. The results showed that the soils would release nitrogen and phosphorus to the overlying water when the soils were inundated. The characteristics of soil affected the equilibrium concentrations of N and P between the soil and the overlying water.

关键词： Three Gorges Reservoir Area nitrogen phosphorus inundated soil

A Study of Grain Growth Kinetics in Sintered NdFeB Magnets

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Journal of Rare Earths 2001年第3期19卷 209-213页

作者：刘湘涟何建平董清飞周寿增 Lab. for Advanced Metals and Mat. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The Nd2Fe14 B grain growth kinetics in sintered NdFeB magnets with nominal compositions of Nd30+xDy1.5Fe67.08-xAl0.4B1.02 (%, x = 0, 3) was studied. The grain size parameters were determined by means of the linear intercept method on SEM secondary electron images. It is observed that the grain growth process is more sensitive to sintering temperature than to sintering time although the grain size rises with both sintering temperature and time. It is also found that magnets prepared from the pre-alloy powder with a higher oxygen content exhibit a lower grain growth rate and magnets made from the pre-alloy powder with a broader particle size distribution demonstrate a higher grain growth rate. It is believed that the presence of appropriate amounts of Nd oxides effectively impedes the grain growth process and a larger difference in sizes between pre-alloy powder particles significantly accelerates the grain growth process. On the basis of experimental results, the grain growth exponent and the corresponding activation energy were obtained. A possible grain growth mechanism in NdFeB magnets during sintering was briefly discussed.

关键词： rare earths NdFeB-type magnet sintering grain growth kinetics

Supercritical gasification for the treatment of o-cresol wastewater

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Journal of Environmental Sciences 2006年第4期18卷 644-649页

作者： WEI Chao-hai HU Cheng-sheng WU Chao-fei YAN Bo College of Environmental Science and Technology South China University of Technology Guangzhou 510640 China

The supercritical water gasification of phenolic wastewater without oxidant was performed to degrade pollutants and produce hydrogen-enriched gases. The simulated o-cresol wastewater was gasified at 440-650℃ and 27.6 MPa in a continuous Inconel 625 reactor with the residence time of 0.42-1.25 min. The influence of the reaction temperature, residence time, pressure, catalyst, oxidant and the pollutant concentration on the gasification efficiency was investigated. Higher temperature and longer residence time enhanced the o-cresol gasification. The TOC removal rate and hydrogen gasification rate were 90.6% and 194.6%, respectively, at the temperature of 650℃ and the residence time of 0.83 min. The product gas was mainly composed of H2, CO2, CFL and CO, among which the total molar percentage of H2 and CFL was higher than 50%. The gasification efficiency decreased with the pollutant concentration increasing. Both the catalyst and oxidant could accelerate the hydrocarbon gasification at a lower reaction temperature, in which the catalyst promoted H2 production and the oxidant enhanced CO2 generation. The intermediates of liquid effluents were analyzed and phenol was found to be the main composition. The results indicate that the supercritical gasification is a promising way for the treatment of hazardous organic wastewater.

关键词： supercritical water gasification o-cresol hydrogen-enriched gas wastewater treatment