选择性化学镍/金工艺的应用

本文主要通过对选择性化学镍／金的生产应用，就流程中的二次干膜、退膜、化学镍金、OSP的相关生产控制进行总结。     

典型SPF级实验动物房气流组织模拟分析

通过对SPF实验动物房内在生态、实验动物笼架横置和竖置等几种情况下的气流组织的模拟,分析了各种气流组织的具体特征,并比较了他们之间的优劣,同时还模拟分析了气流组织和室内污染物之间的关系,就如何优化实验动物房内的气流组织得出了相关结论和建议。     

真空装置中的常见污染和清洁处理

主要介绍了真空装置中常见污染的形成、类型以及清洁处理的方法和真空工艺对环境的要求。     

污染数据线性回归模型参数估计的两个问题

研究了简单回归模型中响应变量在某一时刻受到另一随机变量序列污染时,模型参数和污染系数的估计方法及其相合性与渐近正态性,并证明了第Ⅰ类污染数据回归模型在假定22σ=l221σ(其中21σ和22σ未知,l2已知)下,其参数的矩估计不存在.     

Analytical issues in monitoring drinking-water contamination related to short-term, heavy rainfall events

Heavy rainfall events, increasing in frequency and intensity with climate change, impact on the quality of the water resource used for drinking-water production. Small-scale water suppliers are particularly sensitive because of their management and the related difficulties of adapting treatment to variations. Decision-support systems, based on monitoring and analytical tools, need to be developed to improve crisis-management procedures related to such events. After presenting the issues related to heavy rainfall events, the article summarizes the tools currently used for quality control of drinking water within this framework, the need for developments and other requirements.     

Trace-level analysis of organic contaminants in drinking waters and groundwaters

We expect drinking water and groundwater samples to be contaminated very little, so they are subject to trace-level analysis. Due to the very low levels of contamination, this sort of analysis requires not only powerful analytical technologies to reach limits around the ng/L level, but also quality-control parameters (e.g., blank and spike samples) to monitor potential contamination or losses during sample treatment. Based on a literature review and laboratory experience, we discuss the problems linked to the difficulties of calculating limits of detection, distinguishing instrumental from methodological limits and preventing false-positive results in cases of sample contamination, or false-negative results in cases of compound losses. When possible, we suggest solutions to compensate for, or to prevent, these problems.     

Evaluation of Pesticide Contamination of Ground Water in Two Agricultural Areas of Portugal

In two Portuguese agricultural areas, "Beira Litoral" and "Ribatejo e Oeste", several pesticides regularly applied in vineyards, maize, potato, tomato for industry, apple, pear and rice were detected in ground water. Atrazine was the most frequently detected, being found in 70% of the total of 79 sites selected in the year 2000, followed by its metabolites desethylatrazine and desisopropylatrazine with frequencies of detection, respectively, of 56% and 48% and by simazine (37%), alachlor (25%), metolachlor (24%) and metribuzin (15%). Other pesticides and metabolites i.e. 3,4-dichloroaniline, dimethoate, f and g -endosulfan, lindane, molinate and prometryn were also detected but at lower occurrences. Pesticides were detected mainly in ground water wells used for irrigation purposes, although in some locations they were also found in water wells used for human consumption. In this study, it was also observed a seasonal variation of pesticide residues in ground water of shallow and deep wells.     

Assessment of pesticide contamination in soil samples from an intensive horticulture area, using ultrasonic extraction and gas chromatography-mass spectrometry

In order to reduce the amount of sample to be collected and the time consumed in the analytical process, a broad range of analytes should be preferably considered in the same analytical procedure. A suitable methodology for pesticide residue analysis in soil samples was developed based on ultrasonic extraction (USE) and gas chromatography–mass spectrometry (GC–MS). For this study, different classes of pesticides were selected, both recent and old persistent molecules: parent compounds and degradation products, namely organochlorine, organophosphorous and pyrethroid insecticides, triazine and acetanilide herbicides and other miscellaneous pesticides. Pesticide residues could be detected in the low- to sub-ppb range (0.05–7.0 μg kg⁻¹) with good precision (7.5–20.5%, average 13.7% R.S.D.) and extraction efficiency (69–118%, average 88%) for the great majority of analytes. This methodology has been applied in a monitoring program of soil samples from an intensive horticulture area in Póvoa de Varzim, North of Portugal. The pesticides detected in four sampling programs (2001/2002) were the following: lindane, dieldrin, endosulfan, endosulfan sulfate, 4,4′-DDE, 4,4′-DDD, atrazine, desethylatrazine, alachlor, dimethoate, chlorpyrifos, pendimethalin, procymidone and chlorfenvinphos. Pesticide contamination was investigated at three depths and in different soil and crop types to assess the influence of soil characteristics and trends over time.     

Isolation and characterization of 4-chlorophenol degrading bacterial strain from pharmaceutical xenobiotic compounds contaminated soil using enrichment technique

4- chlorophenol is available as the fundamental basic compound of numerous manufactured organics. It is produced from various sources like herbicides, wood additives, oil industries, pharmaceutical drugs and so on. It can be removed from the effluent by various ways but most effective method is bioremediation. In present study, aerobic bacterial strain was isolated from soil that was contaminated with pharmaceutical xenobiotic compounds using enrichment technique with 500 ppm of 4-chlorophenol as a sole source of carbon and energy. Colonies were isolated after 24 h of incubation on petri plate by media enrichment with 500 ppm of 4- chlorophenol and serial dilution method. 18 colonies were isolated and examined for their ability to degrade 500 ppm of 4-chlorophenol. The most potent strain, C17 was able to remove nearly ～99.93% of 4-chlorophenol in 24 h, 37 °C temperature and 6.8 pH. Based on morphological, biochemical, nucleotide homology and phylogenetic analysis the strain was found to have maximum similarity (98.98%) with Bacillus timonensis strain 10403023.     

Bayesian robustness under a skew-normal class of prior distribution

We develop a global sensitivity analysis to measure the robustness of the Bayesian estimators with respect to a class of prior distributions. This class arises when we consider multiplicative contamination of a base prior distribution. A similar structure was presented by van der Linde [12]. Some particular specifications for this multiplicative contamination class coincide with well known families of skewed distributions. In this paper, we explore the skew-normal multiplicative contamination class for the prior distribution of the location parameter of a normal model. Results of a Bayesian conjugation and expressions for some measures of distance between posterior means and posterior variance are obtained. We also elaborate on the behavior of the posterior means and of the posterior variances through a simulation study.