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排序方式: 共有466条查询结果,搜索用时 15 毫秒
381.
研究了阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)和阴离子表面活性剂十二烷基硫酸钠(SDS)对活性污泥脱水和沉降性能的影响,及其改善活性污泥脱水效能的作用机理。结果表明,质量分数8%的CTAB可使污泥比阻(SRF)从8.5×1012 m/kg降为7.5×1011 m/kg,滤饼的含水率降至75%左右,污泥的沉降性能最好,上清液的浊度也较小。相比之下,SDS对污泥沉降、脱水性能的改善效果明显逊于CTAB。实验表明, 表面活性剂主要是通过溶出胞外聚合物(EPS)破坏污泥结构释放内部结合水来加快污泥的沉降速度和提高其脱水性能。 相似文献
382.
Huan He Qinjin Yu Chaochao Lai Chen Zhang Muhan Liu Bin Huang Hongping Pu Xuejun Pan 《Frontiers of Environmental Science & Engineering》2021,15(2):18-30
383.
Spoors JA Winger LA Siew LK Dessi JL Jennens L Self CH 《Journal of environmental monitoring : JEM》2002,4(6):917-921
To date, no ligand binding assay has been described for the carbamate herbicide asulam, although a variety of physical methods, dependent on pre-concentration of water samples, have been documented for its assessment. However, asulam is increasingly used in sensitive agricultural areas, and statutory regulations concerning its monitoring will undoubtedly become more stringent. Antibodies are optimal partners in ligand binding assays, but it is commonly understood by immunological researchers that where no antibody reactive with a particular antigen has yet been described, the immunogenicity of the antigen may be particularly restricted. By the expedient of employing a specialised approach to final immunisation with an asulam-protein conjugate, prior to the immortalisation of a specific anti-asulam antibody-producing cell, we have succeeded in generating a monoclonal antibody reactive specifically with asulam that can be configured in a convenient immunoassay. This antibody may be used flexibly in a number of ways: small sample volumes of 10 microl can be assessed to sensitivities of 4.35 x 10(-7) M (10 microg L(-1)) while avoiding discrepancies contributed by the assay matrix; this antibody-based assay can also be formatted to deliver sensitivities at levels stipulated by regulatory authorities (e.g., 4.35 x 10(-9) M or 0.1 microg L(-1)) directly from a water sample, without prior pre-concentration. 相似文献
384.
N‐acetyltransferase (NAT) activity was determined in 100 fish (Oreochromis mossambicus) livers using 2‐aminofluorene and p‐aminobenzoic acid as substrates. Overall, the liver NAT activity of the 50 females was higher than the liver NAT activity of the 50 males. The activities (mean ± SD) of NAT from kidney, blood, intestine, and liver of males was 0.42 ± 0.11, 0.12 ± 0.03, 0.12 ± 0.08, and 1.56 ± 0.54 nmol/min/mg protein for the acetylation of 2‐aminofluorene and 0.36 ± 0.09, 0.09 ± 0.01, 0.11 ± 0.04, and 0.46 ± 0.15 nmol/min/mg protein for the acetylation of p‐aminobenzoic acid. In kidney, blood, intestine, and liver from female fish, the activities obtained were 1.60 ± 0.12, 0.35 ± 0.07, 0.15 ± 0.09, and 1.89 ± 0.50 nmol/min/mg protein for 2‐aminofluorene and 0.95 ± 0.11, 0.27 ± 0.03, 0.13 ± 0.09, and 0.57 ± 0.12nmol/min/mg protein for p‐aminobenzoic acid. Kinetic constants for arylamine N‐acetyltransferase activity in kidney, blood, intestine, and liver from fish with rapid, intermediate, and slow acetylator activity were determined. Apparent K m and V max values for 2‐aminofluorene were 5.5 and 7‐fold higher for liver than for the other tissues. Apparent K m and V max values for p‐aminobenzoic acid were 3.5 and 4.7‐fold higher for liver than for the other tissues. Based on the 2‐aminofluorene NAT activity of liver, there appears to be a polymorphism in NAT activity with 16 rapid, 28 intermediate, and 56 slow acetylators among the 100 fish assayed. This is the first demonstration of acetyl CoA: arylamine N‐acetyltransferase activity in fresh water fish and could lead to the development of a fish model for monitoring the effect of pollution of water environments on native species. 相似文献
385.
研究了基于高分辨率卫星遥感影像的公路水毁灾情信息提取模型,通过解决跨软件环境的开发问题,实现了基于遥感与地理信息系统混合编程的公路水毁灾情信息提取系统。使用高分辨率卫星遥感数据形成融合数据,通过分析融合图像的光谱、几何、纹理特征,建立了公路信息提取规则,构建了面向对象的公路信息提取模型。根据水在近红外和中红外波长范围内反射率极低的特性,同时考虑不同环境背景造成的信息提取复杂性,研究了具有自适应特点的水面提取模型。通过建立组件式地理信息系统和遥感应用环境之间的通信和数据共享机制,实现了模型运行的交互式用户界面,并提供叠置空间分析功能,从灾后公路边界提取结果中去除水面部分,获得公路水毁信息。实际应用表明,系统可以满足相关工作对公路水毁灾情信息提取技术的要求。 相似文献
386.
387.
388.
本文介绍了以氧瓶燃烧法处理煤样,氯化亚锡还原汞离子,用冷原子吸收法测定汞的含量。同时,对氧瓶燃烧法处理煤样的可靠性进行了考察。 相似文献
389.
Zhang Nan Lai Hui Ying Gautam Archana De Kwek Darien Yu Dong Yibing Wang Qiang Ng Kee Woei 《Journal of Polymers and the Environment》2022,30(3):1045-1054
Journal of Polymers and the Environment - Hair contains about 80% keratins and 1–3% melanin packaged in melanosomes. Both of these are high-value and functional raw materials that have... 相似文献
390.
Alvin C.K. Lai Tracy L. Thatcher William W. Nazaroff 《Journal of the Air & Waste Management Association (1995)》2013,63(9):1688-1699
ABSTRACT To facilitate routine health risk assessments, we develop the concept of an inhalation transfer factor (ITF). The ITF is defined as the pollutant mass inhaled by an exposed individual per unit pollutant mass emitted from an air pollution source. A cumulative population inhalation transfer factor (PITF) is also defined to describe the total fraction of an emitted pollutant inhaled by all members of the exposed population. In this paper, ITFs and PITFs are calculated for outdoor releases from area, point, and line sources, indoor releases in single zone and multizone indoor environments, and releases within motor vehicles. Typical PITFs for an urban area from emissions outdoors are ~10-6–10-3. PITFs associated with emissions in buildings or in moving vehicles are typically much higher, ~10-3–10-1. 相似文献