气相色谱法测定地表水中百菌清和菊酯类农药

采用正己烷萃取地表水中的百菌清和6种菊酯类农药,通过毛细管气相色谱法-电子捕获检测器(GC-ECD)定性定量。供试农药的线性范围:百菌清为10.0μg/L～200μg/L,6种菊酯类为50.0μg/L～1 000μg/L;方法检出限分别为:百菌清0.054μg/L,甲氰菊酯0.62μg/L,三氟氯氰菊酯0.68μg/L,氯菊酯0.40μg/L,氯氰菊酯0.65μg/L,氰戊菊酯0.78μg/L,溴氰菊酯0.15μg/L;对地表水样品3个质量浓度水平的平均加标回收率为91.3%～118%,6次平行测定的RSD<5%。     

射阳港区规划对盐城自然保护区的生态影响研究

结合工程特点、港区规划范围自然保护区生态环境现状,识别和分析射阳港区规划实施后对盐城自然保护区的生态影响。结果表明,底栖生物丧失,浮游生物和鱼类减少,船舶溢油事故及建设和运营期三废的排放导致海域生态环境质量下降;溢油使鸟类生境遭到破坏,保护区结构和功能受阻等。提出相应的环保措施,最大限度减轻规划实施后对自然保护区的影响。     

TU-1901紫外可见分光光度计用于污水中酚类和苯胺类的快速测定

介绍了用ＴＵ１９０１紫外可见分光光度计直接、快速测定环境污水中酚类和苯胺类的实验方法。污水样品用１∶１盐酸调ｐＨ为３０±０１,直接测绘吸收光谱,微机４阶微分后即可同时获得酚类和苯胺类的含量,方法简捷、快速、节省试剂且无污染,所用仪器为国产的先进仪器,在环境监测领域有广阔的应用前景     

Influence of plants on the reduction of hexavalent chromium in wetland sediments

This work addresses the effect that plants (Typha latifolia and Carex lurida) have on the reduction of Cr(VI) in wetland sediments. Experiments were carried out using tubular microcosms, where chemical species were monitored along the longitudinal flow axis. Cr(VI) removal was enhanced by the presence of plants. This is explained by a decrease in the redox potential promoted by organic root exudates released by plants. Under these conditions sulfate reduction is enhanced, increasing the concentration of sulfide species in the sediment pore water, which reduce Cr(VI). Evapotranspiration induced by plants also contributed to enhance the reduction of Cr(VI) by concentrating all chemical species in the sediment pore water. Both exudates release and evapotranspiration have a diurnal component that affects Cr(VI) reduction. Concentration profiles were fitted to a kinetic model linking sulfide and Cr(VI) concentrations corrected for evapotranspiration. This expression captures both the longitudinal as well as the diurnal Cr(VI) concentration profiles.     

A modeling study of coarse particulate matter pollution in Beijing: regional source contributions and control implications for the 2008 Summer Olympics

In the last 10 yr, Beijing has made a great effort to improve its air quality. However, it is still suffering from regional coarse particulate matter (PM10) pollution that could be a challenge to the promise of clean air during the 2008 Olympics. To provide scientific guidance on regional air pollution control, the Mesoscale Modeling System Generation 5 (MM5) and the Models-3/Community Multiscale Air Quality Model (CMAQ) air quality modeling system was used to investigate the contributions of emission sources outside the Beijing area to pollution levels in Beijing. The contributions to the PM10 concentrations in Beijing were assessed for the following sources: power plants, industry, domestic sources, transportation, agriculture, and biomass open burning. In January, it is estimated that on average 22% of the PM10 concentrations can be attributed to outside sources, of which domestic and industrial sources contributed 37 and 31%, respectively. In August, as much as 40% of the PM10 concentrations came from regional sources, of which approximately 41% came from industry and 31% from power plants. However, the synchronous analysis of the hourly concentrations, regional contributions, and wind vectors indicates that in the heaviest pollution periods the local emission sources play a more important role. The implications are that long-term control strategies should be based on regional-scale collaborations, and that emission abatement of local sources may be more effective in lowering the PM10 concentration levels on the heavy pollution days. Better air quality can be attained during the Olympics by placing effective emission controls on the local sources in Beijing and by controlling emissions from industry and power plants in the surrounding regions.     

钢渣-锰渣复合陶粒对Pb2+的动态吸附

水体重金属污染愈发严重,其中Pb²⁺是毒害性大的重金属之一。该文成功地制备了一种钢渣-锰渣复合陶粒(SS-MS),并利用自制吸附柱进行动态试验过程中,对吸附Pb²⁺的可行性进行了深入的研究。SS-MS对Pb²⁺的吸附符合Langmuir吸附方程(R²=0.999)和McKay二级动力学模型(R²=0.979 4),说明SS-MS吸附铅离子主要利用单层化学吸附。研究了动态吸附过程中的吸附柱和初始浓度的影响,结果表明：随着初始浓度的降低和吸附柱高的升高,吸附能力呈增加的趋势,在适当的环境条件下达到了较高的吸附能力。采用Thomas、Yoon-Nelson、BDST模型进行分析,Thomas模型和Yoon-Nelson模型的相关系数R²>0.92,BDST模型在h=5 cm时相关系数R²值为0.997 89。并通过SEM-EDS探究微观变化,阐明了吸附机理。因此,SS-MS被认为是一种具有良好性能的吸附材料,特别是来自受污染位点的Pb...     

不同SOC调整方法对锂电池撞击测试影响的研究

UN38.3是目前国际上普遍采用的锂电池运输标准,其中撞击测试是最难通过的测试项目之一.本文以最常见的18650型锂电池作为实验对象,按照UN38.3第七版标准要求,研究了不同荷电状态(SOC)调整方法对撞击测试结果的影响.研究表明不同的充电方式会造成初始SOC的差异,最终导致目标SOC状态不同.电池容量虚标越高,荷电...     

工伤认定之要件

2003年4月27日,《工伤保险条例》经国务院第5次常务会议讨论通过予以公布,正式拉开了我国工伤保险全面推行的序幕。10年间,我国工伤保险在取得丰硕成绩的同时,不断面临挑战。站在这个历史的转折点上,我们特邀西北大学法学院于欣华副教授撰写系列文章,带我们一起细细品味工伤保险的点滴故事,观其从何处来,思其将向何处去,领略一番别样工伤保险的风情,以飨读者。     

水中扑草净的气相色谱法测定

扑草净(prometryne),化学名称:2-甲硫基-4,6-双异丙胺基均三氮苯。纯品为白色结晶,易溶于有机溶剂,20℃时在水中溶解度为48ppm。工业原粉为浅灰色粉末,是一种高效低毒的内吸型除草剂。国内未见有工业废水中扑草净最高容许排放浓度标准利分析方法,苏联工业废水排放标准为5.0毫克/升,美国环保局推荐用电解电导率检测器或氮特效热离子检测器的气相色谱     

西红柿生长期加盐有益

英国苏塞克斯园艺研究所的科学家发现,在西红柿植株生长期间,让它吸收一些盐,能够使结出的西红柿更甜。科学家把西红柿植株栽培在加盐的营养液中,这样可以改变西红柿的酸糖度,从而使西红柿