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大气CO2浓度升高对农田生态系统的影响 总被引:1,自引:0,他引:1
自由大气CO2浓度升高(简称FACE,即Free A ir CO2Enrichment)对陆地生态系统的影响是全球变化研究中的一个热点。综述了FACE条件下,农田土壤植物生物量质量变化和土壤微生物对植物的反馈作用,以及土壤痕量气体排放的趋势变化。 相似文献
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Effects of the surface chemistry of macroreticular adsorbents on the adsorption of 1-naphthol/1-naphthylamine mixtures from water 总被引:1,自引:0,他引:1
ZHANG Wei-ming CHEN Jin-long CHEN Qun HE Min-yang PAN Bing-cai ZHANG Quan-xing 《环境科学学报(英文版)》2005,17(5):782-785
The adsorption behaviors of 1-naphthol, 1-naphthylamine and l-naphthol/l-naphthylamine mixtures in water over two macroreticular adsorbents were investigated in single or binary batch systems at 293 K, 303 K and 313 K respectively. All the adsorption isotherms in the studied systems can be adequately fitted by Langmuir model. In the case of aminated macroreticular adsorbent NDA103, 1-naphthol is adsorbed to a larger extent than 1-naphthylamine; while, the opposite trend is found for nonpolar macroreticular adsorbent NDA100. It is noteworthy that at higher temperature(303 K and 313 K), the total uptake amounts of 1-naphthol and 1-naphthylamine in all binary-component systems are obvious larger than the pure uptake amounts in single-component systems, which is presumably due to the cooperative effect primarily arisen from the hydrogen-bonding interaction between the loaded 1-naphthol and 1-naphthylamine molecules. The simultaneous adsorption systems were confirmed to be helpful to the selective adsorption towards 1-naphthol according to the larger selective index. 相似文献
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YU Guang-ning ZHANG Chun-hui SU Zhong-jie FAN Xue-li PAN Yong-zhan LIU Fu-shun . Civil engineering institute Qingdao Technological University Qingdao . Engineering college Ocean University of China Qingdao . Liaoning Technical University Fuxin 《地球与环境》2005,33(Z1):17-26
<正>To control land surface subsidence caused the underground mineral exploitation and the catastrophic phenomena such as serious damage of buildings, waterbodies, cultivated lands, railways, bridges caused by land subsidence, bed separation grouting technology of overburden is put forward. To provide theoretical support for the technology, the characteristics and the mechanics mechanism of mining overburden from layer-split to formation of bed separation are studied. On the basis of elastic sheet board theory, calculation formula of rock sheet deflection is presented, and the mechanics criteria of the separation formation and the calculation formula of bed separation volume are set up. Finally, the applications and technics of bed separation grout technology of mining overburden to control land subsidence in china are introduced. 相似文献
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运用评价化学品毒性藻类测试的标准实验方法,得到铜、锌和锰对月形藻生长的最小无显著差异浓度(LNOEC)分别为31.8μg/L、16.4μg/L和2.7mg/L,抑制月形藻生长的96h半效应浓度(96h-EC50)分别为199.5μg/L、38.0μg/L和12.6mg/L。实验结果表明无论从LNOEC还是从96h-EC50考虑,都证明抑制月形藻生长的毒性由大到小的顺序是锌>铜>锰。此结果对铜抑制藻类生长的毒性远远大于锌的毒性这一人们普遍认同的观点构成挑战。月形藻细胞壁表面可能含有较少的硫代基团但包含较多与锌有很强结合能力的官能团可能是导致月形藻对铜的敏感性弱而对锌敏感性强的主要原因。 相似文献
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In the present study, the sorption of pyrene on two kinds of bulk paddy soils, Gleyic Stagnic Anthrosols, and Ferric accumulic Stagnic Anthrosols as well as their particle-size fractions was investigated. The sorption isotherms fitted well with Freundlich equation. For both soils, the clay fraction( 〈 2μm) and coarse sand fraction(2000-250μm) had higher sorption capacity than fine sand fraction(250-20 μm) and silt fraction(20-2 μm). The IogKoc values obtained of each soil and its particle-size fractions were similar, proving that SOM content was a key factor affecting pyrene sorption. The Kd values showed a significant correlation with contents of dithionite-extractable Fe in both paddy soils and a good relationship with CEC in Gleyic Stagnic Anthrosols, indicating possible effects of surface properties of particle-size fractions on the sorption of pyrene. 相似文献
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Transformation of chlorophenols by nanoscale bimetallic particles represents one of the latest innovative technologies for environmental remediation. Nanoscale Pd/Fe bimetallic particles were synthesized in the laboratory for treatment of o-chlorophenol. Most of the nanoscale particles are in the size range of 20-100 nm. BET specific surface area of the nanoscale Pd/Fe particles is 12.4 m2/g. In comparison, a commercially available Fe powder( < 100 mesh) has a specific surface area of just 0.49 m2/g. Batch experiments demonstrated that the nanoscale Pd/Fe bimetallic particles can effectively dechlorinate o-chlorophenol. Dechlorination efficiency is affected by the mass fraction of Pd in the bimetal, nanoscale Pd/Fe mass concentration and mixing intensity. 相似文献