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991.
本文主要讨论用离子色谱法测定降水氟含量时,怎样消除“水负峰”的干扰,并评价了氟离子选择电极法测定降水氟含量的适用情况,以寻求一种在不同分析条件下采用不同方法,准确测定降水氟含量的途径。 相似文献
992.
南京市降水化学成分特征及变化趋势 总被引:13,自引:0,他引:13
通过对1992-1998年南京市降水化学成分特征及其变化趋势的分析,表明南京市降以化明显,但无恶化迹象,降水化学成分中SO^2-4对酸化起主要作用,但其作用呈下降趋势,而NO^-3,Cl^-的作用呈上升趋势。Ca^2+,NH^4+在中和降水的酸性方面起十分重要的作用,Ca^2+的作用逐渐减弱,而NH^+4的作用则逐渐增大。 相似文献
993.
在建设项目竣工环境保护验收监测报告的编写及技术审核中,经常会出现验收报告中的水量统计等数据跟环评报告中的一样,污水处理设施各环节的监测数据缺乏逻辑性,数据的合理性经不起推敲等问题.验收监测报告,不能过度依赖环评数据,应根据现场核实的实际生产工艺制作水平衡图,由原辅材料用量、水量等数据的相关性获取真实数据,才能反映污染物的产生量等真实情况;应通过掌握设施的进、出水量,将设施各工序的实际处理效率与污水处理工艺的设计参数做比较,才能对设施的处理能力、处理效果作出准确的评价.才能保证验收监测报告的真实性、准确性. 相似文献
994.
Elzbieta Dabkowska Anna Machoy-Mokrzynska Jerzy Straszko Zygmunt Machoy Dorota Samujlo 《Environmental geochemistry and health》1995,17(4):155-158
The factories processing natural phosphates and apatites in Poland release into the atmosphere considerable amounts of fluorine compounds. Fluoride is known to accumulate in the hard tissues of animals and humans. This paper describes the determination of fluoride in mandibles of deer in the years 1982 and 1990. In recent years, the establishments have restricted their output and modernized the technology of phosphate fertilizer production. The fluoride content in jaws has decreased, particularly in those animals having their habitat in the vicinity of the two factories. 相似文献
995.
Intra-specific interactions influence egg composition in the lesser black-backed gull (Larus fuscus)
Nanette Verboven Neil P. Evans Liliana D’Alba Ruedi G. Nager Jonathan D. Blount Peter F. Surai Pat Monaghan 《Behavioral ecology and sociobiology》2005,57(4):357-365
Egg composition, which is under maternal control, can have a profound effect on offspring fitness. The presence of maternal testosterone and carotenoids in avian egg yolk, for example, is thought to enhance the development and competitive ability of the offspring and protect the hatching and growing chick against oxidative stress. Egg quality often differs between females and such variation can be due to differences in maternal social environment, e.g. breeding density. However, this is confounded by the possibility that the quality of individuals breeding in high- or low-density areas may vary. We tested if maternal social environment influences egg composition in a colonial seabird, the lesser black-backed gull (Larus fuscus). To control for confounding effects of female quality, we experimentally manipulated maternal social environment during egg formation. We increased the frequency of intra-specific interactions (i.e. aggressive encounters with conspecifics other than nest mates) in which the females were involved, by placing an elevated platform in their territory. Females that took part in more intra-specific interactions produced a heavier last egg, but the yolk testosterone concentration in eggs laid by control and experimental females did not differ. Differences in yolk testosterone concentration in relation to embryo sex were found neither in the control nor in the experimental group. In contrast, within the control group, eggs with a male embryo contained more carotenoids than eggs with a female embryo. Moreover, experimental females that had been involved in more intra-specific interactions produced female eggs with higher carotenoid levels compared to female eggs of control birds. An experimental increase in carotenoid levels was not observed in eggs containing a male embryo. Our results suggest that intra-specific interactions experienced by female birds during egg formation can influence conditions for embryonic development.Communicated by J. Graves 相似文献
996.
To balance advantages and disadvantages of group living, some species have fission-fusion social systems in which members of the same group form frequently changing subgroups. This allows flexible responses of group size to external conditions while at the same time retaining group stability. In chimpanzees, subgroup (party) size and composition depend mainly on the presence of receptive females, food availability and the activity of the party. Here we analyse the extent to which fission-fusion parameters are influenced by changes of demographic variables like community size and composition. Data were collected from a habituated West African chimpanzee community (Taï forest, Côte dIvoire) over 10 years, during which total community size decreased from 51 to 21, and the number of adult males decreased from 9 to 2. Taï chimpanzees are highly gregarious, as they spend more than 80% of their time with unrelated conspecifics. With decreasing community size, party size, party duration and male-female association increased. Neither activity nor the presence of receptive females or feeding competition could explain the observed changes in grouping patterns. Thus, the decrease in community size led to an increase of party cohesion and also enhanced cohesiveness between the sexes, while general sociality remained unchanged. Therefore, our data support the notion that small communities are more cohesive and have a less flexible fission-fusion system.Communicated by D. Watts 相似文献
997.
998.
The role of atmospheric aerosol composition in climate change 总被引:1,自引:0,他引:1
The chemical composition of atmospheric aerosols has been investigated. Contributions ofsulfate and soot in aerosols to the atmospheric extinction are studied. Discussions are made on the problems of aerosol emitted from volcano, forest fires in northern China, 1987 and oil field fires in Kuwait, 1991. It is indicated that the changes in concentration, particle size, and chemical composition of aerosol after those events could have impacts on the climate change either regionally or globally and that the impact of aerosol particles on climate change could compensate for some temperature increase caused by greenhouse gases and the increase of surface intensity of ultraviolet radiation due to ozone layer depletion. 相似文献
999.
1000.
华南花岗岩类可以看成一个整体。随着时代的更替,其化学成分呈现有规律的递变。两个地质时代岩石平均成分的差异,是化学演化真实存在的重要证据。本文在此基础上,提取岩石化学分析数据的特征信息。将华南五个期次的花岗岩体作为标准样本,利用模糊滤波器,对湖北随州市北部地区的6个岩体及196个南岭地区的花岗岩体进行评判。其结果表明,利用岩石的化学分析结果,可以建立花岗岩体的年龄“时间表’。 相似文献