高浓度有机废水处理技术的发展

本文对高浓度有机废水的处理进行了一些探讨,并主要讲述了ＵＡＳＥ反应器的发展,特点及其在高浓度有机废水方面的应用。     

糖蜜酒精废水两相UASB处理工艺的酸化段特征

文章考察了糖蜜酒精废水二相UASB处理工艺的酸化段特征 ,试验结果表明酸化段的容积负荷达到3 0kgCOD/m3 时 ,系统仍能正常运行 ,TOC去除率在 3 5%以上 ,酸化段的SO4 2 -去除率在 70 %。糖蜜酒精废水酸化率在 50 % ,二相厌氧生物处理系统并未将产酸微生物与产甲烷微生物截然分开 ,在产酸相中仍含有一定数量的产甲烷菌。     

静态环境下阿特拉津的生物降解研究

从农药厂阿特拉津生产车间污泥中分离出菌种AT菌,进行了系列降解实验.不同温度的降解实验表明,在4～20℃的实验温度范围内,AT菌能够降解代谢污染质,并随温度的升高,降解能力增强.20℃时降解率为38.84%;AT菌在外加氮源、碳源及以阿特拉津为惟一碳源和氮源等条件时对农药污染质阿特拉津均具有降解能力,且在以阿特拉津为惟一氮源(外加碳源)条件下的降解效果最好,此时的降解率为30.39%.     

Estimation of residue levels and dietary risk assessment of cyproconazole and azoxystrobin in cucumber after field application in China

Residue field trials in cucumber were conducted for the safe use of a commercial formulation of cyproconazole·azoxystrobin 28% suspension concentrate (SC 294 g a.i. ha^?1, three applications at a 7-day interval) in the year 2018, in China. To determine the residues of cyproconazole and azoxystrobin in cucumber, a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was developed using high-performance liquid chromatography coupled with tandem mass spectrometry. This validated method was applied to analyze cucumber samples collected from 12 specified regions. At the 3-day interval to harvest, the highest residue (HR) of azoxystrobin was 0.150 mg kg^?1, which was lower than the maximum residue limit (MRL; 0.5 mg kg^?1) permitted in China, and the HR of cyproconazole was 0.084 mg kg^?1, for which no MRL value has been set in China. The chronic risk quotient values of cyproconazole and azoxystrobin for Chinese adults at a 3-day interval to harvest were 2.56% and 13.72%, respectively. The acute risk quotient values of cyproconazole in cucumber were specified as 5.52% for children (1–6 years old) and 2.83% for the adults (>?18 years old) in China. These results indicate that cyproconazole·azoxystrobin 28% SC sprayed on cucumber at the pre-harvest interval of 3 days has no significant potential risk for Chinese consumers.

     

紫外线消毒技术在污水处理中的应用

介绍了紫外消毒的机理、影响紫外消毒的因素以及紫外消毒装置的基本结构形式。阐述了紫外消毒的现状和应用前景 ,提出紫外消毒可能取代传统的化学消毒法 ,在污水处理 ,特别是回用水的处理中得到广泛的应用。     

冲孔废料回升的产生与防止三例

结合3个典型实例,对零件在冲孔时废料回升的现象进行了分析,讨论了采用不同厚度的材料、不同的孔形、不同的冲裁间隙所产生的不同情况,介绍了在生产现场解决问题的方法和防止废料回升的一般措施.根据对具体实例的分析,总结出了控制废料回升的要点.     

A SCALE‐INVARIANT GAUSS‐MARKOV MODEL FOR DESIGN STORM HYETOGRAPHS1

Abstract. Hyetographs are essential to many hydrological designs. Many studies have shown that hyetographs are specific to storm types and durations. Recent work presented evidence that dimensionless hyetographs are scale invariant. We show that the simple scaling property of rainfall guarantees that the normalized rainfall rates of different storm durations are identically distributed and propose a nonstationary Gauss‐Markov model based on the annual maximum events that arise from the dominant storm type. We derive the unique estimators for the parameters of the Gauss‐Markov model under two constraints that: (a) the typical peak rainfall rate is preserved, and (b) the most likely hyetograph is obtained. One attractive feature of this model is that it allows translating hyetographs between storms of different durations. Two examples illustrate our model.     

Oceanic diffusion and the pelagic insects Halobates spp. (Gerridae: Hemiptera)

Five pelagic Halobates species occupy a vast area from 40^∘ north to 40^∘ south in the three major oceans. Oceanic diffusion, constantly acting to disperse these insects, must be an important factor in determining their life history and distribution. We investigated the effects of oceanic diffusion on the following aspects of these insects. (1) The estimated radius of a patch of Halobates could be expanded by oceanic diffusion alone from an initial point of origin to 1250 km in 60 d. This distance is about 1/12 of the maximum distributional range of H. micans in the Pacific Ocean. Mutual encounter rates due to oceanic turbulence could be as high as 11 d⁻¹ even at low population densities (100 ind km⁻²). This suggests that individuals from their original habitat could find mates even when they had been carried a long distance. Thus, extensive gene mixing may occur over the whole range of a species' distribution. (2)␣Estimated growth rates are rather low (0.0026 to 0.0079 d⁻¹) compared with those of other insects. However, they are offset by a long life span (over 90 d) and an extended oviposition period (perhaps over 2␣months). Thus, pelagic Halobates spp. appear to have adopted a strategy of slow growth and prolonged longevity to cope with living in an unstable physical environment that is constantly disturbed by storms and winds. Received: 5 February 1995 / Accepted: 30 October 1997     

The effect of carbonate and biochar on carbon and nitrogen losses during composting

Journal of Material Cycles and Waste Management - Limited options and high prices have limited the application of additives in composting. The effect of applying carbonate (SRC) and biochar (BC) to...     

基于ICA/MNF变换的高分影像滑坡灾害检测方法研究

快速准确地从灾后影像中提取出受灾区域对于灾后救援具有重要意义。鉴于现有提取方法过度依赖滑坡在影像中的光学、纹理等特征的问题,研究了一种结合独立成分分析(ICA)与最小噪声比率变换(MNF)的变化检测方法,以单一时相的影像为基础,运用基于负熵最大化的Fast-ICA算法分离出两个时相影像相互正交的独立成分,并构建对应独立成分的差异影像,最后用最小噪声比率变换实现分布于各个差异影像上变化信息的集中,应用直方图阈值法得到了最终的滑坡灾害信息。选取了滑坡灾害前后两时相的高分辨率遥感影像数据进行实验,结果证实了方法的可行性。