全文获取类型
收费全文 | 109篇 |
免费 | 8篇 |
国内免费 | 27篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 21篇 |
环保管理 | 5篇 |
综合类 | 71篇 |
基础理论 | 17篇 |
污染及防治 | 11篇 |
评价与监测 | 16篇 |
社会与环境 | 1篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 2篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 9篇 |
2005年 | 10篇 |
2004年 | 8篇 |
2003年 | 3篇 |
2002年 | 11篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 1篇 |
排序方式: 共有144条查询结果,搜索用时 9 毫秒
31.
Background, Aims and Scope Secondary inorganic aerosol (SIA), i.e. particulate sulphate (S(VI)), ammonium and nitrate (N(V)) is formed from gaseous
precursors i.e., sulfur dioxide (S(IV)), ammonia and nitrogen oxides, in polluted air on the time-scale of hours to days.
Besides particulate ammonium and nitrate, the respective gaseous species ammonia and nitric acid can be formed, too. SIA contributes
significantly to elevated levels of respirable particulate matter in urban areas and in strongly anthropogenically influenced
air in general.
Methods The near-ground aerosol chemical composition was studied at two stationary sites in the vicinity of Berlin during a field
campaign in summer 1998. By means of analysis of the wind field, two episodes were identified which allow to study changes
within individual air masses during transport i.e., a Lagrangian type of experiment, with one station being upwind and the
other downwind of the city. By reference to a passive tracer (Na+) and estimates on dry depositional losses, the influences
of dispersion and mixing on concentration changes can be eliminated from the data analysis.
Results and Discussion Chemical changes in N(-III), N(V) and S(VI) species were observed. SIA i.e., N(V) and S(VI), was formed from emissions in
the city within a few hours. The significance of emissions in the city was furthermore confirmed by missing SIA formation
in the case of transport around the city. For the two episodes, SIA formation rates could be derived, albeit not more precise
than by an order of magnitude. N(V) formation rates were between 1.4 and 20 and between 1.9 and 59 % h-1 on the two days,
respectively, and S(VI) formation rates were > 17 and > 10 % h-1. The area south of the city was identified as a source of
ammonia.
Conclusion The probability of occurrence of situations during which the downwind site (50 km downwind of Berlin) would be hit by an
urban plume is > 7.4%. Furthermore, for the general case of rural areas in Germany it is estimated that for more than half
of these there is a significant probability to be hit by an urban plume (> 8%). The S(VI) formation rates are higher than
explainable by homogeneous gas-phase chemistry and suggest the involvement of heterogeneous reactions of aerosol particles.
Recommendation and Outlook The possible contribution of heterogeneous processes to S(VI) formation should be addressed in laboratory studies. Measurements
at more than two sites could improve the potential of Lagrangian field experiments for the quantification of atmospheric chemical
transformations, if a second downwind site is chosen in such a way that, at least under particular stability conditions, measurements
there are representative for the source area. 相似文献
32.
钛基燃烧催化剂的抗硫性能 总被引:1,自引:0,他引:1
本文研究了钛基非贵金属燃烧催化剂的硫中毒过程及载体吸硫特性。结果表明,催化剂的抗硫能力与载体吸硫量有关,不同催化剂的抗硫性能为:Cat.3>Cat.4>Cat.5>Cat.1>Cat.2,本文还讨论了硫中毒机理。 相似文献
33.
Alfred J. Vella Alex Camilleri Jean Pierre Tabone Adami 《Environmental geochemistry and health》1996,18(4):165-170
The concentration of sulphate on limestone surfaces of the external walls of churches in Malta is shown to be related to their position and distance from a power station, the main local point source of sulphur dioxide pollution. Limestone powder collected from these surfaces was examined for the presence of particles which, under low-power optical microscopy, appear as shiny black amorphous bodies which were interpreted as soot particles; the abundance of these bodies was expressed as a black particle count (BPC). The degree of sulphation and BPC were shown to be correlated with each other and both appeared to be strongly dependent on the prevailing wind. The BPC contour map indicated an important contribution to the parameter from vehicular traffic. It is suggested that the degree of sulphation and BPC of limestone surfaces from the built environment should function as environmental indicators of the relative air quality with respect to SO2 and soot pollution. This data is possibly more accurately representative of the relative long-term air-quality status of different areas of habitation than that deduced from single or episodic measurements of atmospheric pollutant levels. 相似文献
34.
35.
对SOx、NOx的存在形态进行了热力学与化学平衡计算,据此提出了监测技术改进的建议。对工程检测、在线连续监测及大气污染物排放量的统计,也提出了初步的设想。 相似文献
36.
张掖市是国务院划定的SO2污染控制区之一,其SO2污染严重程度居全国前列,本研究以环境空气SO2监测和SO2污染源监测调查为基础,以ATDL模式为模拟手段,对张掖市SO2控制区的污染源进行了解析,分析找出造成该控制区SO2污染的根本原因,从而为制定SO2污染总量控制方案奠定科学基础。 相似文献
37.
硫/石灰石滤柱的自养反硝化动力学模型 总被引:1,自引:0,他引:1
本文对用硫作为电子供体,硝酸盐作为电子受体,由脱氮硫杆菌进行的自养反硝化过程的动力学模型进行了研究。结果表明,硝酸盐在滤料表面生物膜中的扩散过程对硫/石灰石滤柱的反硝化动力学影响很大。若扩散速率慢,硝酸盐只能穿过生物膜的一部分,则滤柱的反硝化速率遵循1/2级反应动力学;若扩散速率快,硝酸盐能穿过整个生物膜,则滤柱的反硝化速率遵循零级反应动力学。 相似文献
38.
丹东市湿式脱硫除尘器的现状评价 总被引:1,自引:0,他引:1
张国荣 《辽宁城乡环境科技》2003,23(4):38-40
湿式脱硫除尘器取代干式除尘器后除尘效率有较大提高,但它用水量大,腐蚀严重,SO2污染加重,运转费用和操作难度大。对改进湿式脱硫除尘器的脱硫、除尘、消烟、设备维护等提出了保证措施。 相似文献
39.
In this study, mangrove seedlings (Kandelia obovata (S. L.)) were cultivated in rhizo-boxes, which contain sediments collected from natural mangrove forest and modified with different rates of sulphate and phosphate. The fraction distributions of Zn, Cd, Cu, Ni and Pb in rhizosphere and non-rhizosphere sediments were studied by using a sequential extraction method. Metal concentrations in plant tissues and iron plaque on root surface were also determined to reveal migration variation of heavy metals in the plant-sediment system. The results showed that the activities of K. obovata roots enhance the reducible metals while reducing acid-extractable and oxidisable metals; sulphur amendment benefits the combination of metal ions with S2– and therefore reduces the bioavailability of metal pollutants; addition of sulphur also improves the content of iron plaque on the root surface, which plays an important role in metal accumulation by K. obovata root tissue; the addition of sulphur markedly reduces the concentration of Cd in roots, but significantly enhanced the concentrations of Cu, Zn, Ni and Pb in roots. The results indicate that sulphur and phosphorus content in mangrove sediment, and the growth of mangrove plant can significantly influence the migration of heavy metals in the mangrove wetland ecosystem. 相似文献
40.