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991.
992.
天津市1997年-2006年相对资源承载力的动态测度与分析 总被引:3,自引:0,他引:3
采用相对资源承载力的研究思路与计算方法,计算1997年-2006年天津市相对自然资源承载力、相对经济承载力和综合承载力及其变化过程。研究表明:(1)与全国比较,天津市资源综合承载力处于富余状态,且经济资源对综合承载力的贡献占大部分;(2)与北京、上海、广东等发达省市相比,天津市综合承栽力处于超载状态,自然资源承载量占优势,但经济资源水平有较大差距。(3)相对水资源承载力对相对自然资源承载力的贡献率基本在50%以上,水资源对其发展具有至关重要的作用。针对天津市相对承载力方面存在的问题,提出了天津实现可持续发展的对策建议:大力发展经济,保护和合理开发利用自然资源,保护生态环境,遏制环境恶化趋势,控制人口增长,不断协调人口、资源、环境和发展的矛盾,逐步走向可持续发展。 相似文献
993.
Hydrophobic organic contaminants (HOCs)—pyrene, and natural organic matters (NOM) from different sources were taken as the
test compounds to investigate the impact of physicochemical characteristics of NOM on HOCs’ partition to the NOM in this study.
The effects of solution property, NOM characteristics, and modification by ozone preoxidation on pyrene partition to NOM were
systematically evaluated. According to the fluorescence quenching method, the partition coefficient K
oc of pyrene to NOM was calculated, which was found to have a great relationship with the aromatic structures and hydrophobic
functional groups of the NOM. The NOM characteristic modification corresponding to solution property could influence the interactions
between the NOM and pyrene. Preozonation could destroy the aromatic or hydrophobic structures of the NOM and decrease K
oc of pyrene. 相似文献
994.
Ming Ge Changsheng Guo Xingwang Zhu Lili Ma Zhenan Han Wei Hu Yuqiu Wang 《Frontiers of Environmental Science & Engineering in China》2009,3(3):271-280
ZnO/TiO2 composites were synthesized by using the solvothermal method and ultrasonic precipitation followed by heat treatment in order
to investigate their photocatalytic degradation of methyl orange (MO) in aqueous suspension under UV irradiation. The composition
and surface structure of the catalyst were characterized by X-ray diffraction (XRD), field emission scanning electron microscope
(FE-SEM), and transmission electron microscopy (TEM). The degradation efficiencies of MO at various pH values were obtained.
The highest degradation efficiencies were obtained before 30 min and after 60 min at pH 11.0 and pH 2.0, respectively. A sample
analysis was conducted using liquid chromatography coupled with electrospray ionization ion-trap mass spectrometry. Six intermediates
were found during the photocatalytic degradation process of quinonoid MO. The degradation pathway of quinonoid MO was also
proposed. 相似文献
995.
Małgorzata Matejko Anthony J. Dore Jane Hall Christopher J. Dore Marek Błaś Maciej Kryza Rognvald Smith David Fowler 《Environmental Science & Policy》2009,12(7):882-896
In the United Kingdom, as with other European countries, land-based emissions of NOx and SO2 have fallen significantly over the last few decades. SO2 emissions fell from a peak of 3185 Gg S in 1970 to 344 Gg S in 2005 and are forecast by business-as-usual emissions scenarios to fall to 172 Gg by 2020. NOx emissions were at a maximum of 951 Gg N in 1970 and fell to 378 by 2005 with a further decrease to 243 Gg N forecast by 2020. These large changes in emissions have not been matched by emissions changes for NH3 which decreased from 315 Gg N in 1990 to 259 in 2005 and are forecast to fall to 222 by 2020. The Fine Resolution Atmospheric Multi-pollutant Exchange model (FRAME) has been applied to model the spatial distribution of sulphur and nitrogen deposition over the United Kingdom during a 15-year time period (1990–2005) and compared with measured deposition of sulphate, nitrate and ammonium from the national monitoring network. Wet deposition of nitrogen and sulphur was found to decrease more slowly than the emissions reductions rate. This is attributed to a number of factors including increases in emissions from international shipping and changing rates of atmospheric oxidation. The modelled time series was extended to a 50-year period from 1970 to 2020. The modelled deposition of SOx, NOy and NHx to the UK was found to fall by 87%, 52% and 25% during this period. The percentage area of sensitive habitats in the United Kingdom for which critical loads are exceeded is estimated to fall from 85% in 1970 to 37% in 2020 for acidic deposition and from 73% to 49% for nutrient nitrogen deposition. The significant reduction in land emissions of SO2 and NOx focuses further attention in controlling emissions from international shipping. Future policies to control emissions of ammonia from agriculture will be required to effect further significant reductions in nitrogen deposition. 相似文献
996.
997.
无铅焊料合金中重金属元素浸出行为的研究 总被引:1,自引:0,他引:1
选用Sn.3.5Ag-0.5Cu、Sn-3.5Ag、Sn-0.5Cu无铅焊料合金及它们与Cu的钎焊接头,研究了它们在典型的酸性、碱性和盐溶液中的重金属元素的浸出规律.结果表明,焊料合金中的主要浸出元素Sn在酸性或碱性溶液中的浸出量都不是太多,而在NaCl盐溶液中浸出量增大2个数量级.制备成钎焊接头后,在酸性环境中,Sn-3.5Ag和Sn.0.5Cu钎焊接头中Sn的浸出量增加1个数量级以上,而在NaOH碱性环境中.Sn-3.5Ag-0.5Cu钎焊接头中Sn的浸出量相对较高.该结果对电子垃圾填埋环境选择及相关决策提供了参考. 相似文献
998.
入侵植物互花米草水浸液对莴苣的化感效应 总被引:1,自引:0,他引:1
选用互花米草根、茎、叶5个浓度梯度(0.065、0.130、0.195、0.260、0.325 g·mL-1)的水浸液为处理液,研究其对莴苣种子萌发及幼苗生长的影响.结果表明:互花米草根水浸液在浓度大于0.260 g·mL-1时会显著抑制莴苣种子的萌发,而茎、叶水浸液产生显著抑制作用的起始浓度分别为0.130 g·mL-1和0.195 g·mL-1;互花米草根、茎、叶水浸液对莴苣种子萌发的抑制,不仅表现为降低种子的最终萌发率,还表现为延长种子的平均萌发周期;茎、叶水授液对幼苗生长的影响比较显著.而根水浸液浓度低于0.195g·mL-1时对幼苗胚轴的生长产生促进作用(敏感指数RI>0).不同构件水浸液化感效应强度由大到小依次为:茎>叶>根.并且化感效应强度随水浸液浓度的增加而增强. 相似文献
999.
通过对苯乙烯装置所涉及物质的风险识别、生产设施的风险识别,分析出这些风险进入外环境的途径以及对外环境造成的环境影响,并制定简单的环境风险防范措施。 相似文献
1000.
介绍了大型储油罐一次机械密封结构改造为一次机械镀锌钢板加内隔膜弹性耐腐蚀橡胶软密封后,一次机械密封与二次机械密封之间的可燃气体浓度由原来的80%LEL以上下降至10%LEL以下,大型储油罐防雷击火灾取得了较好的效果。 相似文献