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731.
甲烷排放源逆向轨迹反演模式研究 总被引:9,自引:0,他引:9
基于逆向轨迹计算和单点浓度连续观测资料建立了一个甲烷排放源的反演模式 .经系统调试表明模式具有正确反映边界层物理过程的能力 .在理想条件下 ,模式相当准确地反演出 1 0 0km水平范围内设定的排放源和分布 .用 9天的实际甲烷浓度连续观测资料对北京地区的排放源情况进行个例计算 ,获得主要源块的排放率在0 0 0 66~ 0 0 2 6mg/ (m2 ·s)范围内 ,与区域内的重要排放源 (稻田 )的排放情况相一致 .反演所得源块与区域内的稻田分布亦有一定的空间对应关系 相似文献
732.
长光路FTIR研究HFC152a光化学反应 总被引:4,自引:1,他引:4
用长光路FTIR技术研究氟里昂替代物HFC152a(CH3CHF2)在对流层中的化学反应,氯离子作反应的引发剂,用相对速度方法测定了HFC152a与Cl原子反应速率常数为(2.3±0.5)×10^-13cm^3·mol^-1·s^-1(298±K)。HFC152a在对流层中的主要含氟光解产物为COF2,产率为88%。有关反应机理进行了讨论。 相似文献
733.
就我国气象法,提出了它的三个属性-经济,行政,国际,并讨论了气象资源服务的四个方面:经济建设,国防建设,社会发展和人民生活。 相似文献
734.
新农药环境化学行为研究(Ⅶ)除草剂哌草丹(Dimepiperate)在土壤、水环境中的滞留、转化 总被引:8,自引:0,他引:8
研究了除草剂哌草丹在土壤、水环境中的吸附、脱附、水解及光解过程.结果指出:哌草丹在土壤上的吸附主要受土壤有机质的影响,粘土矿也有一定作用.吸附和脱附均可用Freundlich方程描述;根据降解产物推测了哌草丹的水解和光降解的机理,哌草丹的水解产物为2-苯基丙烯和六氢吡啶等,六氢吡啶可与土壤粘土矿(蒙脱石)作用,并与蒙脱石层间阳离子形成配合物;哌草丹光降解的产物为六氢吡啶、苯乙酮和甲醛. 相似文献
735.
Acute toxicity of benzene derivatives to the tadpoles (Rana japonica) and QSAR analyses 总被引:2,自引:0,他引:2
Acute lethal toxicity (the negative logarithm of molar concentrations of 12 h acute median lethal, expressed as 12 h-log1/LC50) of 46 benzene derivatives to Rana japonica tadpoles was determined. 1-octanol/water partition coefficient (logKow)-dependent models were developed to study the toxicity of different categories chemicals. In an effort to model all chemicals, response surface analyses and stepwise multiple regression analyses were performed and successful models were obtained. A general and robust QSAR model was achieved with the combined application of variables reflecting hydrophobicity, electric property, and molecular size respectively (12h-log1/LC50 = 0.393logKow - 0.428Elumo + 0.0110Vol. + 1.362 n = 51, r2 = 0.834) using stepwise multiple regression analyses. Because of strong dissociation of carboxyl group greatly decreasing their observed toxicity, using logDow in instead of logKow the quality of the models is greatly improved. The conventional r2 and cross-validation r2(CV) were 0.914 and 0.785, respectively, indicating that QSAR was both internally consistent and highly predictive. 相似文献
736.
砂对海水中溶解油的吸附及影响因素研究 总被引:2,自引:0,他引:2
以柴油污染的海水为对象,研究了砂对海水中溶解油的吸附作用及吸附的影响因素。结果表明,砂对溶解油的吸附符合Henry型吸附等温式,其吸附量随着砂粒粒径的减小、温度的降低和盐度的增加而增大。在影响吸附的3种因素中,粒径对吸附的影响最大。通过吸附热力学分析,推断砂对溶解油的吸附属于物理吸附。 相似文献
737.
738.
Due to the powerful graphic interface in modern computers, visualization techniques have become more and more popular for data exploration. As a preliminary investigation, visualization is a greatly useful tool to lead to further statistical analysis and modelling. It is likely that historical environmental data from a range of different studies may contain useful information that should be assessed for determining management actions. However, these historical data are collected from many different studies, which have different space and/or time scales making the visualization process complicated. In this paper we present several ways of visualizing historical data based on a study at Sydney Olympic Park. The tools include spatial coverage and variation for different spatial resolutions, temporal coverage and time series plots for different time scales, multi-panel scatterplots for a small number of variables and "one-to-all" scatterplots for a large number of variables. 相似文献
739.
740.
Phylogenetic diversity of Archaea in prawn farm sediment 总被引:2,自引:0,他引:2
Peng?Shao Yueqin?ChenEmail author Hui?Zhou Lianghu?Qu Ying?Ma Heyang?Li Nianzhi?Jiao 《Marine Biology》2004,146(1):133-142
The structure and diversity of the Archaea collected from prawn farm sediment were investigated for the first time. A partial 16S ribosomal DNA library was constructed with Archaea-specific primers. Subsequently, 80 randomly selected archaeal clones from the library were analyzed by restriction fragment length polymorphism (RFLP), and resulted in 50 different RFLP patterns. Sequence analysis of representatives from each unique RFLP type revealed high diversity in the archaeal populations, and the majority of archaeal clones were either members of novel lineages or most closely related to uncultured clones. In the phylogenetic analysis, the archaeal clones could be grouped into discrete phylogenetic lineages within the two kingdoms Crenarchaeota and Euryarchaeota. Euryarchaeota dominated in our archaeal library, with up to 72.2% of the total clones, and Crenarchaeota represented 27.8%. Of all the Euryarchaeota clones, three clones (5.6%) were affiliated with Methanosarcinales, four clones (7.4%) were related to Methanomicrobiales, three clones (5.6%) were related to Halobacterium (with 93% similarity), and the remaining clones (81.5%) were related to those uncultured Euryarchaeota in the aquatic sediment ecosystem. None of the crenarchaeal clones were associated with any known cultured lineages. The selective dispersal of the archaeal population indicates that their ecological niches are associated with environmental characteristics. Novel phylotypes of Archaea would expand our understanding of the genetic diversity of Archaea in aquatic sediment systems and would be significant in the phylogenetic study of Archaea.Communicated by O. Kinne, Oldendorf/Luhe 相似文献