石墨炉升温程序的灰化技术

本文以测定铅为例,研究了石墨炉升温程序的灰化技术,包括基体干扰的消除,基体改进剂和Ｌ’ｖｏｖ平台的应用。     

日本废弃物的管理制度与研究现状Ⅲ.日本废弃物的试验分析方法体系(C)产业废弃物的分析方法

本文简要介绍了日本产业废弃物的监测分析方法     

Assessment of indoor radiation level in the environs of the uranium deposit area of West Khasi Hills District,Meghalaya, India

An estimation of the indoor background radiation dose distribution was carried out in dwellings of eleven villages located within and around the uranium mineralization area of Kylleng-Pyndensohiong, Mawthabah in West Khasi Hills District of Meghalaya, India. The ambient indoor gamma radiation level was monitored using Thermo Luminescence Dosimeters (TLDs) while the indoor radon and thoron concentration was measured using twin-cup dosimeters employing Solid State Nuclear Track Detectors (SSNTDs). Results obtained from the study reveals that the local inhabitants of villages located close to the mining site receive higher doses than those inhabitants of villages located at a much farther distance from the mining site. The average total annual effective dose was found to be varying from 1.2 mSv y⁻¹ in the village of Langpa to 3.4 mSv y⁻¹ in the village of Nongbah Jynrin. The data obtained will serve as a reference in documenting changes to environmental radioactivity if mining is to be carried out in the future.     

电焊熔珠对棉布和聚氨酯泡沫的引燃能力研究

研究了加载电压对电焊熔珠数目和粒径分布的影响,在模拟装置上实验了电焊对棉布、聚氨酯泡沫和纸张的引燃性能.结果表明,随着加载电压升高,电焊熔珠的数目逐渐减少,熔珠粒径逐渐增大,引燃能力逐渐增强.固体材料性质对电焊熔珠引燃能力也有很大影响,表面粗糙,易蓄热材料容易被点燃.电焊熔珠引燃棉布、聚氨酯泡沫和纸张的临界电压为37.5V、40V和45V.     

SPME/GC-MS在对火场残留物分析中的应用及其数据分析

本文利用固相微萃取(SPME)的高富集性和气相色谱-质谱(GC-MS)的精确性,采用SPME/GC-MS方法对模拟纵火现场中的常见火灾残留物进行分析,并通过比较其特性化合物,很大程度上提高了判断的准确性.利用二甲基苯、三甲基苯、四甲基苯及甲基萘类化合物各自异构体的特征比值,可以很好地减少分析过程中背景干扰.通过向量夹角法进行相似度分析可以帮助判断干扰物的影响.     

ASE萃取-SPE净化-气相色谱法测定土壤中有机氯农药

建立了加速溶剂萃取-固相萃取净化-气相色谱测定土壤中α-六六六、β-六六六、γ-六六六、δ-六六六、P,P′-DDE、P,P′-DDD、O,P′-DDT、P,P′-DDT等8种有机氯农药的方法。在0μg／L～500μg／L范围内方法线性良好,8种有机氯农药的检出限在0．06μg／kg～0．21μg／kg之间,基质加标试验的相对标准偏差为2．2％～5．8％,回收率为81．5％～113％。     

浅议现代垃圾填埋场的大气污染及监测分析方法

造成垃圾填埋场大气污染的两大类污染物,其对环境、人体、动植物、器物和材料都有一定的危害,文章针对现代垃圾填埋场的大气环境污染,以硫化氢、氨、甲硫醇等重点大气污染因子为监测对象,结合实践总结了一部分垃圾填埋场的大气污染监测方案,包括布点原则、采样频率和时间、采样方法和分析技术,该监测方案可为现代垃圾填埋场的大气污染监测提供参考.     

固相微萃取与气相色谱-质谱联用测定饮用水中甲基叔丁基醚

采用固相微萃取与气相色谱-质谱联用测定饮用水中甲基叔丁基醚(MTBE),研究了萃取头涂层材料、萃取温度、盐浓度、萃取时间和溶液的pH值等操作条件对分析方法的影响.该方法分析MTBE的线性范围0.01-10μg/L,检出限0.66ng/L.0.01μg/L的MTBE水样五组平行测定实验中,相对标准偏差为4.8%.用所建立的方法测得大兴某地下水中MTBE的含量0.8μg/L,加标回收率达到90%.     

Biodiesel production from waste oil feedstocks by solid acid catalysis

Biodiesel is a non-toxic and biodegradable substitute for petroleum-based diesel. However, it is impractical to use refined edible oils to produce biodiesel due to its high cost and priority for food products, especially in China, while waste oils with high free fatty acids (FFAs) can be considered as the raw materials. In the present work, a solid acid catalyst comprising SO₄²⁻/TiO₂–SiO₂ was prepared, characterized and studied for its activity for the production of biodiesel from several low cost feedstocks with high FFAs. The solid acid catalyst can be recycled, easily removed and can simultaneously catalyze esterification and transesterification. The influence of reaction parameters was studied, and the optimized reaction parameters are reaction temperature 200 °C, molar ratio of methanol to oil 9:1 and catalyst concentration 3 wt.%. The catalyst showed good stability. A continuous process for biodiesel production from cheap raw feedstocks was proposed, and a 10,000-tonnes/year biodiesel production demonstration plant has been built.