Separation of selected PAHs by using high performance capillary electrophoresis with modifiers

The effect of varying SDS concentration in a micellar electrokinetic capillary chromatographic system (MECC) is investigated. In addition, the introduction of -cyclodextrin as modifier to the electrophoretic medium, containing SDS and a phosphate-borate buffer, is shown to give satisfactory separation of the seven selected PAHs. The separation efficiency is increased with the addition of -cyclodextrin.     

Modeling the spatial pattern of farmland using GIS and multiple logistic regression: a case study of Maotiao River Basin, Guizhou Province, China

Land use change is an important topic in the field of global environmental change and sustainable development. Land use change modeling has attracted substantial attention because it helps researchers understand the mechanisms of land use change and assists regulatory bodies in formulating relevant policies. Maotiao River Basin is located in the province of Guizhou, China, which has a developed agricultural industry in the karst mountain areas. This paper selected biophysical and social–economic factors as independent variables, and constructed a multiple logistic regression of farmland spatial distribution probability by random sampling. Then, by using GIS technology and integrating the 2000 data, this study predicted the farmland spatial pattern. When the predicted map was compared with the actual farmland map for 2000, we noted that 71% of the simulation is in accordance with the 2000 farmland pattern. The result satisfactorily proves the reasonability and applicability of our model.     

Performance evaluation of a sorbent tube sampling method using short path thermal desorption for volatile organic compounds

Air sampling, using sorbents, thermal desorption and gas chromatography, is a versatile method for identifying and quantifying trace levels of volatile organic compounds (VOCs). Thermal desorption can provide high sensitivity, appropropriate choices of sorbents and method parameters can accommodate a wide range of compounds and high humidity, and automated short-path systems can minimize artifacts, losses and carry-over effects. This study evaluates the performance of a short-path thermal desorption method for 77 VOCs using laboratory and field tests and a dual sorbent system (Tenax GR, Carbosieve SIII). Laboratory tests showed that the method requirements for ambient air sampling were easily achieved for most compounds, e.g., using the average and standard deviation across target compounds, blank emissions were < or = 0.3 ng per sorbent tube for all target compounds except benzene, toluene and phenol; the method detection limit was 0.05 +/- 0.08 ppb, reproducibility was 12 +/- 6%, linearity, as the relative standard deviation of relative response factors, was 16 +/- 9%, desorption efficiency was 99 +/- 28%, samples stored for 1-6 weeks had recoveries of 87 +/- 9%, and high humidity samples had recoveries of 102 +/- 12%. Due to sorbent, column and detector characteristics, performance was somewhat poorer for phenol groups, ketones, and nitrogen containing compounds. The laboratory results were confirmed in an analysis of replicate samples collected in two field studies that sampled ambient air along roadways and indoor air in a large office building. Replicates collected under field conditions demonstrated good agreement except for very low concentrations or large (> 41 volume) samples of high humidity air. Overall, the method provides excellent performance and satisfactory throughput for many applications.     

浅谈GAM与GM（1,1）模型

对ＧＡＭ水环境预测模型提出了四点不同看法，与有关作者商榷，指出ＧＭ（１，１）模型与ＧＡＭ模型二者并无优劣之差，精度亦相当。     

珍贵油料植物诸葛菜的研究

四川大学植物遗传研究室经过几年的调查研究,发现诸葛菜的农艺性状较好,分枝多、角果多,每果子粒多,千粒重较重,含油量较高,特别是油分品质优异,其营养价值高的脂肪酸如油酸和亚油酸的含量较高,分别为20.32％,和53.17％,其营养价值低的脂肪酸如亚麻酸和芥酸的含量较低,分别为4.76％和0.94％,是油菜优质育种的优异新种源,可以作为油菜远缘杂交育种亲本,并可能选育出优质油料新作物。本文对诸葛菜的开花授粉习性作了观察,对核型特点作了分析,可供育种工作的参考,诸葛菜主产中国。四川大学在国内外首先推荐这种有希望的油料新种源。     

New method for determination of arsenic contentin tail gases during semiconductor processing

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深圳港盐田港区生态环境影响回顾性分析

根据历次盐田港港口建设所进行的生态环境现状调查资料，对盐田港建港至今的生态环境进行分析，得出盐田港所在海域的生态环境质量状况并未因港口的建设和规模扩大而发生明显变化的结论。     

浅谈环境管理体系中目标和指标及方案管理

文章从环境目标、指标和方案的制订、展开、执行和评价四个环节,来探索ISO14001环境管理体系中目标、指标和方案的管理方法.     

河西走廊灌溉农业发展的水资源承载能力分析

论文采用模糊综合评判方法,对河西走廊灌溉农业发展的水资源承载能力进行了分析,建立了评价的数学模型。研究表明,该区水资源开发利用已近于其饱和容量,发展节水灌溉,充分提高水的利用效率,是保障和发展干旱区农业的根本出路。     

PASS42在微污染饮用水原水处理中的应用研究

:用所研制的混凝剂聚硅硫酸铝对珠江中下游河段原水进行处理 ,改变混凝水力条件 ,对其混凝过程进行了研究并作了经济分析