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A Comparative Analysis of Environmental Quality Assessment Methods for Heavy Metal-Contaminated Soils 被引量:34
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作者 LI Wei-Xin ZHANG Xu-Xiang +5 位作者 WU Bing SUN Shi-Lei CHEN Yan-Song PAN Wen-Yang ZHAO Da-Yong CHENG Shu-Pei 《Pedosphere》 SCIE CAS CSCD 2008年第3期344-352,共9页
Four assessment methods (two pollution indexes and two fuzzy mathematical models) were employed to investigate the environmental quality of four soils around a ferroalloy plant in Nanjing City. Environmental quality... Four assessment methods (two pollution indexes and two fuzzy mathematical models) were employed to investigate the environmental quality of four soils around a ferroalloy plant in Nanjing City. Environmental quality was assessed as class Ⅳ (moderately polluted) for each soil with single-factor index method, and was identified to be classes Ⅳ, Ⅲ (slightly polluted), Ⅲ, and Ⅲ for soils A, B, C, and D, respectively, with the comprehensive index model. In comparison with the single-factor index method, the comprehensive index model concerned both dominant parameter and average contribution of all factors to the integrated environmental quality. Using the two fuzzy mathematical methods (single-factor deciding and weighted average models), the environmental risks were determined to be classes Ⅳ, Ⅲ, Ⅱ (clean), and Ⅱ for soils A, B, C, and D, respectively. However, divergence of the membership degree to each pollution class still occurred between the two methods. In fuzzy mathematical methods, membership functions were used to describe the limits between different pollution degrees, and different weights were allocated for the factors according to pollution contribution. Introduction of membership degree and weight of each factor to fuzzy mathematical models made the methods more reasonable in the field of environmental risk assessment. 展开更多
关键词 environmental assessment fuzzy mathematical model heavy metal pollution pollution index method SOIL
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Effects of hydrodynamics processes on phosphorus fluxes from sediment in large,shallow Taihu Lake 被引量:26
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作者 YOU Ben-sheng ZHONG Ji-cheng +3 位作者 FAN Cheng-xin WANG Tong-cheng ZHANG Lu DING Shi-ming 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第9期1055-1060,共6页
The turnover of phosphorus (P) in lake sediments, a major cause of eutrophication and subsequent deterioration of water quality, is in need of deep understanding. In this study, effects of resuspension on P release ... The turnover of phosphorus (P) in lake sediments, a major cause of eutrophication and subsequent deterioration of water quality, is in need of deep understanding. In this study, effects of resuspension on P release were studied in cylindrical microcosms with Yshape apparatus. The results indicated that there was a positive correlation between flux of suspended substance across sediment-water interface (Fss) and the wind speed, and an increasing Fss during each wind process followed by a steady state. The maximal Fss under fight, moderate, and strong wind conditions were 299.9±41.1,573.4±61.7, and 2093.8±215.7 g/m^2, respectively. However, flux of P across sediment-water interface (Fp) did not follow a similar pattern as Fss responding to wind intensity, which increased and reached the maximum in initial 120 rain for fight wind, then decreased gradually, with maximal flux of 9.4±1.9 mg/m^2. A rapid increase of Fp at the first 30 rain was observed under moderate wind, with maximal flux of 11.2±0.6 mg/m^2. Surprisingly, strong wind caused less Fp than under light and moderate wind conditions with maximal flux of 3.5±0.9 mg/m^2. Fss in water column declined obviously during the sedimentation process after winds, but Fp varied with wind regime. No obvious difference was detected on Fp after 8 h sedimentation process, compared with the initial value, which means little redundant P left in the water column after winds. 展开更多
关键词 hydrodynamic process RESUSPENSION SEDIMENTATION phosphorus flux Taihu Lake
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Aerosol effects on ozone concentrations in Beijing:A model sensitivity study 被引量:20
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作者 Jun Xu Yuanhang Zhang +1 位作者 Shaoqing Zheng Youjiang He 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2012年第4期645-656,共12页
Most previous O3 simulations were based only on gaseous phase photochemistry. However, some aerosol-related processes, namely, heterogeneous reactions occurring on the aerosol surface and photolysis rate alternated by... Most previous O3 simulations were based only on gaseous phase photochemistry. However, some aerosol-related processes, namely, heterogeneous reactions occurring on the aerosol surface and photolysis rate alternated by aerosol radiative influence, may affect O3 photochemistry under high aerosol loads. A three-dimensional air quality model, Models-3/Community Multi-scale Air Quality-Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution, was employed to simulate the effects of the above-mentioned processes on O3 formation under typical high O3 episodes in Beijing during summer. Five heterogeneous reactions, i.e., NO2, NO3, N2O5, HO2, and O3, were individually investigated to elucidate their effects on O3 formation. The results showed that the heterogeneous reactions significantly affected O3 formation in the urban plume. NO2 heterogeneous reaction increased O3 to 90 ppb, while HO2 heterogeneous reaction decreased O3 to 33 ppb. In addition, O3 heterogeneous loss decreased O3 to 31 ppb. The effects of NO2, NO3, and N2O5 heterogeneous reactions showed opposite O3 concentration changes between the urban and extra-urban areas because of the response of the reactions to the two types of O3 formation regimes. When the aerosol radiative influence was included, the photolysis rate decreased and O3 decreased significantly to 73 ppbO3. The two aerosol-related processes should be considered in the study of O3 formation because high aerosol concentration is a ubiquitous phenomenon that affects the urbanand regional air quality in China. 展开更多
关键词 AEROSOL heterogeneous reactions OZONE radiative influence
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Characteristics of microfauna and their relationships with the performance of an activated sludge plant in China 被引量:5
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作者 ZHOU Kexin XU Muqi +1 位作者 LIU Biao CAO Hong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第4期482-486,共5页
The occurrence and abundance of the microfauna groups were compared with the physico-chemical and operational parameters of the Baoding Lugang Sewage Treatment Plant in China. Attached and crawling ciliates were the d... The occurrence and abundance of the microfauna groups were compared with the physico-chemical and operational parameters of the Baoding Lugang Sewage Treatment Plant in China. Attached and crawling ciliates were the dominant groups of ciliates. Crawling ciliates and testate amoebae showed a strong association with effluent BOD5 (biochemical oxygen demand). Therefore, these two groups are likely to be useful bioindicators since their number decreased as the process produced poor quality effluent. Testate amoebae also had significant negative correlations with effluent TN (total nitrogen), NH4^+-N, SS (suspended solids) and SVI (sludge volumetric index), which means that this group of ciliates may be indicators of good performance of the activated sludge system. Carnivorous ciliates and flagellates had significant positive correlations with SVI, suggesting that these two groups may be indicators of bad settlement conditions of sludge. As identification of the microfauna species is difficult and time-consuming, we recommend using microfauna functional groups to evaluate the performance of the activated sludge system. 展开更多
关键词 MICROFAUNA activated sludge INDICATORS sludge biotic index (SBI)
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Plant Pb Contents in Elevation Zones of the Changbai Mountain National Nature Reserve, China 被引量:4
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作者 BAI Jun-Hong CUI Bao-Shan +2 位作者 DENG Wei WANG Qing-Gai DING Qiu-Yi 《Pedosphere》 SCIE CAS CSCD 2007年第2期229-234,共6页
Typical plants and soils of four elevation zones, mountain tundra (Zone A), Betula ermanii forest (Zone B), mountain dark coniferous forest (Zone C), and mountain coniferous and broad-leaf forest (Zone D), alo... Typical plants and soils of four elevation zones, mountain tundra (Zone A), Betula ermanii forest (Zone B), mountain dark coniferous forest (Zone C), and mountain coniferous and broad-leaf forest (Zone D), along the vertical gradient of the northern mountain slope of the Changbai Mountain National Nature Reserve, Jilin Province, China, were sampled to study the relationship between plant and soil Pb, and to compare the Pb levels in typical plant types within the same elevation zone. The Pb contents in the soil and plant samples were measured by using a flame atomic absorption spectrophotometer. The results showed that the average plant Pb contents of the four plant elevation zones were lower than the average worldwide level, except for Zone B. Compared with the average level in China or the average worldwide level, the soil Pb levels of the four plant zones were higher, with Zones D and B having the lowest and highest averages, respectively. Plant Pb levels fluctuated from the upper to the lower zones, in a pattern of low-high-low-high, which was the same as that of the soils in the four zones. Furthermore, plant Pb was closely related to soil Pb. Depending on the plant species and plant parts, large differences were found in the Pb levels of typical plants within each zone. In Zone A, Vaccinium uliginosum and Rhododendron redowskianum had higher Pb levels than the other plants. In Zone C, the Pb levels in the branches of both plant species were higher than those in the leaves, which was contrary to Zone D. In Zone B, the Pb levels in the plant parts varied greatly with plant species. 展开更多
关键词 elevation zone plant Pb Pb uptake soil Pb typical plants
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Review of challenges and strategies for balanced urban-rural environmental protection in China 被引量:2
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作者 Beidou XI Xiaoguang LI +6 位作者 Jixi GAO Ying ZHAO Hongliang LIU Xunfeng XIA Tianxue YANG Lieyu ZHANG Xuan JIA 《Frontiers of Environmental Science & Engineering》 SCIE EI CAS CSCD 2015年第3期371-384,共14页
With the rise of environmentalism in China, great efforts have been devoted to environmental protec- tion over the past several decades. Compared with urban environmental protection, rural environmental protection has... With the rise of environmentalism in China, great efforts have been devoted to environmental protec- tion over the past several decades. Compared with urban environmental protection, rural environmental protection has not been attached enough importance in China due to the dual-track structure of socio-economic development. As a result, rural China is shouldering disproportionally heavy environmental burdens partly because of the differences and biases between urban and rural environmental protection seen in environmental policies, environ- mental rights and interests, environmental protection investment, and the environmental protection awareness of people. To eliminate the gap between rural and urban environmental protection, and achieve the goal of "balanced urban-rural environmental protection" (BUREP), government should consider mapping out proper policies and strategies. In this paper we put forward an innovative strategy of BUREP against the background of China's urban-rural environmental protection. First, we review the current status of rural environmental protection status and its challenges compared with urban environ- mental protection in China. Secondly, we analyzed the main driving factors and reasons deeply, and then we put forward the BUREP strategy base on the unequal status between urban and rural environment. Finally, we proposed the framework of BUREP. This study may serve as a scientific reference regarding decision-making in coordinating urban and rural environmental protection and in constructing the new countryside of China. 展开更多
关键词 urban environment rural environment balanced urban--rural environmental protection framework of balanced urban-rural environmental protection (BUREP)
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Impacts of the Rising Opportunity Cost of Farm Labor on Agricultural Land Use Structure: Theory and Empirical Evidences 被引量:2
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作者 Tian Yujun Li Xiubin +1 位作者 Ma Guoxia Hao Haiguang 《Chinese Journal of Population,Resources and Environment》 2011年第1期85-90,共6页
Nowadays the rising of opportunity cost of farm labor comes to the forefront of attention in China. In order to understand its impact on agricultural land-use structure, a theoretical framework of household economics ... Nowadays the rising of opportunity cost of farm labor comes to the forefront of attention in China. In order to understand its impact on agricultural land-use structure, a theoretical framework of household economics is formulated drawn on Low's model. Under the theoretical framework, the impact of the rising opportunity cost of on-farm on cropping structure is deduced in theory. And then, using statistic and survey data, taking mountain area of southern Ningxia as an example, the theoretical assumes are verified. The results show that the rise of opportunity cost of farm labor leads to less diversified cropping structure. 展开更多
关键词 opporttmity cost of farm labor agricultural land use structure theoretical analysis empirical study
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Effect of unequal injection rates and different hopping rates on asymmetric exclusion processes with junction 被引量:1
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作者 肖松 蔡九菊 +1 位作者 刘飞 刘明哲 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第9期42-52,共11页
In this paper, the effects of unequal injection rates and different hopping rates on the asymmetric simple exclusion process (ASEP) with a 2-input 1-output junction are studied by using a simple mean-field approach ... In this paper, the effects of unequal injection rates and different hopping rates on the asymmetric simple exclusion process (ASEP) with a 2-input 1-output junction are studied by using a simple mean-field approach and extensive computer simulations. The steady-state particle currents, the density profiles, and the phase diagrams are obtained. It is shown that with unequal injection rates and different hopping rates, the phase diagram structure is qualitatively changed. The theoretical calculations are in good agreement with Monte Carlo simulations. 展开更多
关键词 asymmetric simple exclusion processes mean-field approximation JUNCTION different hopping rates
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A comparison of the RCM and ISC3 dispersion models against the Alaska data set
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作者 陈刚才 杨多兴 王中琼 《Chinese Journal Of Geochemistry》 EI CAS 2006年第3期255-257,共3页
The USEPA (U.S. Environmental Protection Agency) approved ISC3 for short-range dispersion modeling. The regulatory model of China is a traditional Gaussian plume model similar to ISC. This paper demonstrates the advan... The USEPA (U.S. Environmental Protection Agency) approved ISC3 for short-range dispersion modeling. The regulatory model of China is a traditional Gaussian plume model similar to ISC. This paper demonstrates the advantages of ISC3 over the regulatory model of China by comparing their predicted ground level concentrations (GLC) along downwind distance to the Alaska tracer field data. The field experiment features buoyant release of effluent at elevated height over a flat terrain and local flows influenced by building downwash. ISC3 shows much better space-time correlation and probability distribution than the China regulatory model, which frequently underestimates the GLC for effluent released with significant plume rise under stable atmospheric conditions. The performance of ISC3 is greatly enhanced by incorporating the state-of-the-art knowledge of boundary layer meteorology. In particular, ISC3 employs the PRIME model for building downwash. 展开更多
关键词 阿拉斯加州 色散 ISC3 RCM 空气
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Tetragonal Distortion of InN Thin Films by RBS/Channeling
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作者 丁志博 吴伟 +2 位作者 王坤 法涛 姚淑德 《Chinese Physics Letters》 SCIE CAS CSCD 2009年第8期234-236,共3页
Rutherford backscattering and channeling spectrometry (RBS/C) are used to identify the crystalline quality (Xmin = 4.87%) Of an InN thin film as a function of depth, and make a non-destructive quantitative analysi... Rutherford backscattering and channeling spectrometry (RBS/C) are used to identify the crystalline quality (Xmin = 4.87%) Of an InN thin film as a function of depth, and make a non-destructive quantitative analysis of the structure, in order to analyze the tetragonal distortion of the InN thin film at the depth determined. 展开更多
关键词 sea surface nonliear interaction numerical method
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Development of Future Generations:Oriented Virtual Negotiation Support System for Intergenerational Conflict
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作者 Zeng Weihua Zhong Xiaohong Xue Pengli 《Chinese Journal of Population,Resources and Environment》 北大核心 2008年第3期63-72,共10页
Intergenerational conflict coordination is the fundamental requirement and core of sustainable development. In this paper, through the analysis of the future generations-oriented management mechanisms for intergenerat... Intergenerational conflict coordination is the fundamental requirement and core of sustainable development. In this paper, through the analysis of the future generations-oriented management mechanisms for intergenerational conflict, the idea of mechanisms and institution building for the coordination and management of intergenerational conflict is put forward. Furthermore, the future generations-oriented virtual negotiation support system (NSS) for intergenerational conflict is developed, built on the analysis of the process simulation of intergenerational wealth transfer, intergenerational equilibrium allocation of resources, and strategies for the mitigation and avoidance of intergenerational conflict, through the application of advanced IT technology. The virtual NSS for intergenerational conflict is helpful to the practical application of the sustainable development theory; on the other hand, it can be applied directly to the intergenerational equilibrium allocation of resources, national economic accounting, formulation of sustainable development strategies and other urgent national economic and social development issues. Finally, the sustainable development theory can be enriched and extended. Therefore, the development of the future generations-oriented virtual NSS for intergenerational conflict has certain theoretical and practical effects on the theory of sustainable development. 展开更多
关键词 intergenerational conflict virtual negotiation support system (NSS) agent of future generations intergenerational equilibrium allocation of resources and wealth process simulation of intergenerational resources consumption and wealth transfer
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Stylet penetration behaviors of the cotton aphid Aphis gossypfi on transgenic Bt cotton 被引量:5
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作者 Kun Xue Xiao-Ying Wang +4 位作者 Cui-Hong Huang Rong-Jiang Wang Biao Liu Feng-Ming Yan Chong-Ren Xu 《Insect Science》 SCIE CAS CSCD 2009年第2期137-146,共10页
Stylet penetration behaviors of cotton aphids Aphis gossypii Glover on a transgenic cotton line "GK-12" expressing Bt toxic protein of Cry 1A (Bt cotton) and a non- Bt conventional cotton line "Simian-3" (CK co... Stylet penetration behaviors of cotton aphids Aphis gossypii Glover on a transgenic cotton line "GK-12" expressing Bt toxic protein of Cry 1A (Bt cotton) and a non- Bt conventional cotton line "Simian-3" (CK cotton) were recorded with the direct current electrical penetration graph (DC-EPG) technique. Cotton aphids reared on Bt cotton (abbreviated as Bt-aphids) and its parental non-Bt control line (CK-aphids) for more than 20 generations each, were used for recordings on two cotton lines. Among 47 selected parameters reflecting the activities of aphid stylets within plant tissues, there were eight parameters of CK-aphids showing significant differences between the performances of CK- aphids on Bt cotton and CK cotton, while for Bt-aphids, all the parameters were statistically equal between the performances on the two cotton lines. All parameters with significant differences indicated that CK-aphids could penetrate into Bt cotton more easily, but the phloem saps of Bt cotton were not as good as those of regular cotton for CK-aphids. Based on the present results, we concluded that there were some factors in Bt cotton affecting penetration behaviors of CK-aphids, but it just took several generations for CK-aphids to completely adapt Bt cotton, and Bt-aphids could feed on two cotton lines without difficulty. 展开更多
关键词 Aphis gossypii Bt cotton electrical penetration graph feeding behavior non-target effects stylet penetration behavior
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Optimal design of coded aperture used for Z-Pinch driven fusion neutron imaging
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作者 JIA QingGang HU HuaSi +5 位作者 ZHENG XiangYang ZHANG FengNa WANG DongMing HU Guang ZHANG TianKui WU YueLei 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第7期1289-1293,共5页
Currently,the neutron yield of Z-Pinch is lower than that of laser driven fusion.In the neutron imaging for this facility,the signal to noise ratio(SNR)has a significant influence on the expected spatial resolution of... Currently,the neutron yield of Z-Pinch is lower than that of laser driven fusion.In the neutron imaging for this facility,the signal to noise ratio(SNR)has a significant influence on the expected spatial resolution of the reconstructed fusion core,especially in the condition of low neutron yield.In this paper,mathematical model is purposed to describe the dependence of aperture parameters on the imaging SNR.The investigation shows that the imaging SNR is closely related to the size of contrast boundary on the point spread function.According to this,a novel non-uniform redundancy penumbra apertures array is designed.In addition,the imaging performances of this novel coded aperture,penumbra aperture and ring aperture are evaluated and compared by Monte Carlo method.The comparison shows that this novel aperture has significant advantage compared to the penumbra aperture which is commonly used for neutron imaging with low yield.The encouraging results can provide reference for the optimal design of the coded aperture used in the neutron imaging for Z-pinch driven fusion with low neutron yield. 展开更多
关键词 Z-pinch driven fusion neutron imaging coded aperture signal to noise ratio low neutron yield
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