The Information Content of a Scalar Plume – A Plume Tracing Perspective

The ability of many animals and insects to track a plume to its source is a particularly impressive feat when the fluid dynamics is considered. Inspired by this observation this research seeks to identify the information in a passive scalar plume suitable for developing robust and efficient plume tracing algorithms. The subject of this study is a scalar plume emanating from a point source in a turbulent boundary layer which has been modeled in a laboratory facility built specifically for this purpose. A coupled PIV-LIF technique is used to measure the velocity and scalar field in a time resolved fashion. This data set is analyzed and the convergence rates of five single-point statistics, suitable as kernels of plume tracing algorithms, are investigated. The experimental data shows that the scalar fluctuations over long downstream distances from the source are characterized by filamentary structures that lead to relatively slow convergence rates for any statistic that is based on mean concentrations. The scalar intermittency, however, converges rapidly toward its true value, in fact converging to a testable hypothesis for source location direction faster than the time scale of the larger scale plume meander.     

高锰酸钾─硫酸─过硫酸钾消化冷原子荧光法测定总悬浮颗粒物中痕量汞

测定环境大气悬浮颗粒物中痕量汞，用４种消化液进行对比实验，其中高锰酸钾─硫酸─过硫酸钾混合液消化效果较好，用冷原子荧光测定操作简便，检测下限为０．０５μｇ／Ｌ，重复测定９个实际样品，相对标准偏差为１１．６％，变异系数为１０．４％，添加汞标准回收率为１０２％。     

有机锡的消解方法研究

对几种消解剂的性能做了比较 ,选用溴化剂对有机锡进行消解 ,消解效率可以达到 80 %以上。利用氢化物发生 -原子荧光光谱法测定消解后的锡 ,方便快捷。该方法相对标准偏差为 2 .6 4 % ,检出限为 7.5 3ng·mL-1。应用于实际样品的测定 ,获得了满意的结果。     

原子荧光法分析地表水中砷的价态

由于砷的化学形态不同,在环境中的毒性、分布、生物效应亦不相同,因而砷的形态分析在环境监测治理中有着不可忽视的重要作用.陆地水中溶解态砷的含量通常在以下,常以砷(三价)、砷(五价)两种价态形式存在,其化合物均有毒性,三价化合物比五价化合物毒性强,多以砷酸盐状态存在.在环境管理中,砷是第一类污染物,环保部门地表水监测也只测总砷,而用氢化物发生原子荧光法可以测定地表水中不同价态的无机砷.在一定的酸度条件下可以选择性地将As3 用硼氢化钾溶液还原成砷化氢,从而将两种价态砷得以有效分离,用原子荧光法测定.As5 在加入还原剂后被还原成As3 ,然后用相同方法测出总砷量,差减去As3 量得到As5 量.此方法灵敏度高,精度好,适用于地表水大量水样中不同价态的砷分析.     

荧光光度法测定土壤中硒的点滴经验

在文献基础上,本人改进了消化液,2,3-二氨基萘(DAN)保存和使用,以及萃取液用量等操作,分析了广东省、海南省共1140个土壤中硒的样品,取得了点滴经验。     

Synchronous fluorescence technique and its use in identification of polynuclear aromatic hydrocarbons in urine samples

The synchronous fluorescence spectroscopy of three polymiclear aromatic hydrocarbons was studied. It was shown that the specific Δλ of the spectra were 10nm for benzo(k) fluoranthene, 25 nm for benzo(a) pyrene, and 40 nm for pyrene. The peaks of the spectra were at 407, 404, and 373 nm for the three chemicals, respectively. Benzo(k) fluoranthene, benzo(a) pyrene, and pyrene in the urine samples from smokers were identified by high pressure liquid chromatography combined with the synchronous fluorescence spectroscopy.     

氢化物发生原子荧光光谱法测定烧结物中的总砷含量

采用氢化物发生原子荧光光谱法测定了烧结物中的总砷含量。烧结物样品通过高压焖罐消解后测定。As^V的线性范围为0－300μg/L。用标准参考物质煤飞灰对方法进行了验证,所得结果与标准参考值相符。本法测定烧结物中总砷含量,样品相对标准偏差小于4％,结果满意。     

巯基纸富集——XRF测定水中Sb(Ⅲ)和Sb(Ⅴ)

在ｐＨ６．０的ＮＨ４ＡＣ－ＨＡＣ缓冲介质中，以巯基纸吸附和富集Ｓｂ（Ⅲ），吸附Ｓｂ（Ⅲ）后的巯基纸用Ｘ射线荧光测定；吸附Ｓｂ（Ⅲ）后的溶液于１ｍｏｌ／ＬＨｃｌ介质中，以巯基纸吸附Ｓｂ（Ⅴ），并按同样方法测定Ｓｂ（Ⅴ）。     

海水中铅的氢化物原子荧光测定

在铁氰化钾体系中以氢化物—原子荧光法直接测定海水中的铅，确定了最佳反应条件。铅的检出限0．18ng／mL，相对标准偏差4．0%，并与石墨炉原子吸收法比对，方法简便、快速，可用于海水中痕量铅的直接测定。     

大气CO2倍增和盐度对滨藜离子水平和叶绿素荧光诱导动力学的效应

研究了ＣＯ２倍增和ＫＣｌ、ＮａＣｌ对盐生植物中亚滨藜幼苗生长，叶绿素含量，Ｋ＾＋、Ｎａ＾＋水平和叶绿素ａ荧光诱导动力学的影响。结果表明，３００ｍｍｏｌ／ＬＮａＯＨ可刺激中亚滨藜的生长，而同浓度的ＫＣｌ则抑制，ＣＯ２倍增使植物株生长增强：