BOD快速测定方法研究进展

综述BOD快速测定方法,快速测定方法包括高温法、相关系数法和生物传感器法。重点论述生物传感器法,讨论生物传感器的工作原理、微生物膜所使用的微生物、传感器的响应方式、影响生物传感器法的因素、该法测试样品所需的时间以及生物传感器法所存在的问题。最后对BOD快速测定方法进行了展望。     

超长污泥龄对MPR工艺脱氮除磷效果的影响

针对高MLSS下系统的稳定运行及脱氮除磷效果,采用微压内循环生物相反应器(MPR)处理模拟城市污水,探究了超长污泥龄(SRT)在50、70、90d时,MPR不断减少剩余污泥排放量下的脱氮除磷效果.结果表明,当SRT由50d提升至90d时,MPR工艺的脱氮能力得到增强,TN的平均去除率由75.97％提高到84.60％.在...     

减灾民用产品开发的可行性研究——以地震安全图动态查询公共系统为例

以地震安全图实时制作与动态查询公共系统开发的必要性与可行性为例,阐述了社会对“自然灾害与安全信息民用产品”的需求,以及它对提高减灾实效、推动灾害与信息科学发展水平的作用。同时介绍了海口市地震安全图实时制作与动态查询公共系统的功能、制作方法和社会用户群体的分析。     

The Avoidance Responses of Daphnia magna to the Exposure of Organophosphorus Pesticides in an On-Line Biomonitoring System

In this study, avoidance behavior of the freshwater cladoceran Daphnia magna Straus was used as indicator to assess the early stress of accidental organophosphorus pesticide (OP) contamination. The movement behavior was detected by a multi-species biomonitoring system. There was obvious concentration–response relationship between the OP stress and the behavioral response even at sublethal exposure. A rising OP stress resulted in a significant decrease of response time to escape (RTE; p<0.05). In comparison of different OPs, it was found that there was a power regression between RTE and the toxic unit of OPs. Therefore, the avoidance behavior of D. magna was a sensitive indicator of sublethal OP stress, and the power relationship could be used to predict the early warning thresholds of more OPs in the on-line biomonitoring system.     

基于人工神经网络的巢湖富营养化分时分区评价

应用人工神经网络方法,以温度、高锰酸盐指数、总磷、总氮作为评价参数,对巢湖湖区12个点位的营养状态进行了分时段评价,一共评价了2000年至2003年四个年度的各月份的营养状态。因为湖泊的营养状态水平是变化的,不同区域、不同时段营养状态水平是不同的,因此采用分区分时评价更能全面客观地反映巢湖的营养状态水平及其变化特征。     

Patch departure rules in Bumblebees: evidence of a decremental motivational mechanism

The patch living rules of a pollinator, the bumblebee Bombus terrestris L., are studied here in the framework of motivational models widely used for parasitoids: The rewarding events found during the foraging process are supposed to increase or decrease suddenly the tendency of the insect to stay in the current patch and therefore to adjust the patch residence time to the patch profitability. The foraging behaviour of these pollinators was observed in two environment types to determine their patch-leaving decisions. The rich environment was composed of male-fertile flowers, offering pollen and nectar, and the poor one of male-sterile flowers, offering little nectar and no pollen. The experimental design consisted of a patch system in which inflorescences were evenly arranged in two rows (1 m distance). Residence times of foragers inside inflorescences and rows were analysed by a Cox proportional hazards model, taking into account recent and past experience acquired during the foraging bout. Most of the results showed a decremental motivational mechanism, that is, a reduction in the residence time on the inflorescence or in the row related to exploitation of flowers within inflorescences and inflorescences within rows These results indicate that bumblebees tend to leave the patch using departure rules similar to those found in parasitoids. The results also provide information on the memory, learning and evaluating capabilities of bumblebees especially when rich and poor environments were compared. The patch-leaving mechanism suggested by this study is consistent with the central place foraging theory.     

Designing environmental monitoring networks to measure extremes

This paper discusses challenges arising in the design of networks for monitoring extreme values over the domain of a random environmental space-time field {X _ij } i = 1, . . . , I denoting site and j = 1, . . . denoting time (e.g. hour). The field of extremes for time span r over site domain i = 1, . . . ,I is given by \(\{Y_{i(r+1)}=\max_{j=k}^{k+n-1} X_{ij}\}\) for k = 1 + rn, r = 0, . . . ,. Such networks must not only measure extremes at the monitored sites but also enable their prediction at the non-monitored ones. Designing such a network poses special challenges that do not seem to have been generally recognized. One of these problems is the loss of spatial dependence between site responses in going from the environmental process to the field of extremes it generates. In particular we show empirically that the intersite covariance Cov(Y _i(r+1),Y _i′(r+1)) can generally decline toward zero as r increases, for site pairs i ≠ i′. Thus the measured extreme values may not predict the unmeasured ones very precisely. Consequently high levels of pollution exposure of a sensitive group (e.g. school children) located between monitored sites may be overlooked. This potential deficiency raises concerns about the adequacy of air pollution monitoring networks whose primary role is the detection of noncompliance with air quality standards based on extremes designed to protect human health. The need to monitor for noncompliance and thereby protect human health, points to other issues. How well do networks designed to monitor the field monitor their fields of extremes? What criterion should be used to select prospective monitoring sites when setting up or adding to a network? As the paper demonstrates by assessing an existing network, the answer to the first question is not well, at least in the case considered. To the second, the paper suggests a variety of plausible answers but shows through a simulation study, that they can lead to different optimum designs. The paper offers an approach that circumvents the dilemma posed by the answer to the second question. That approach models the field of extremes (suitably transformed) by a multivariate Gaussian-Inverse Wishart hierarchical Bayesian distribution. The adequacy of this model is empirically assessed in an application by finding the relative coverage frequency of the predictive credibility ellipsoid implied by its posterior distribution. The favorable results obtained suggest this posterior adequately describes that (transformed) field. Hence it can form the basis for designing an appropriate network. Its use is demonstrated by a hypothetical extension of an existing monitoring network. That foundation in turn enables a network to be designed of sufficient density (relative to cost) to serve its regulatory purpose.     

Effects of a gradually increased load of fish waste silage in co-digestion with cow manure on methane production

This study examined the effects of an increased load of nitrogen-rich organic material on anaerobic digestion and methane production. Co-digestion of fish waste silage (FWS) and cow manure (CM) was studied in two parallel laboratory-scale (8 L effective volume) semi-continuous stirred tank reactors (designated R1 and R2). A reactor fed with CM only (R0) was used as control. The reactors were operated in the mesophilic range (37 °C) with a hydraulic retention time of 30 days, and the entire experiment lasted for 450 days. The rate of organic loading was raised by increasing the content of FWS in the feed stock. During the experiment, the amount (volume%) of FWS was increased stepwise in the following order: 3% – 6% – 13% – 16%, and 19%. Measurements of methane production, and analysis of volatile fatty acids, ammonium and pH in the effluents were carried out. The highest methane production from co-digestion of FWS and CM was 0.400 L CH4 gVS^?1, obtained during the period with loading of 16% FWS in R2. Compared to anaerobic digestion of CM only, the methane production was increased by 100% at most, when FWS was added to the feed stock. The biogas processes failed in R1 and R2 during the periods, with loadings of 16% and 19% FWS, respectively. In both reactors, the biogas processes failed due to overloading and accumulation of ammonia and volatile fatty acids.     

酒石酸钾钠溶液对氨氮标准曲线的影响

通过对酒石酸钾钠溶液存放时间和保存条件的跟踪试验,发现该试剂的存放时间越长,绘制的氨氮标准曲线的截距就越大;并分析了在绘制氨氮标准曲线时显色液易浑浊和截距常常偏大的原因;就此提出了酒石酸钾钠溶液的有效期和保存方法,以进一步提高氨氮测定的准确度。     

建筑材料放射性测量中存在的技术问题

阐述了GB 50325-2001《民用建筑工程室内环境污染控制规范》中存在的问题,指出该规范仅对建筑材料放射性的测量不确定度D(当K=1时,D≤20%)提出了要求,未对测量时间、仪器测量下限和放射性物质特征峰漂移提出要求.实验证明,这些存在的问题对建筑材料放射性测量数据的准确性有影响.