淀粉-g-丙烯酸/凹凸棒土复合物制备及其吸附废水中NH_4~＋-N性能

采用反相乳液聚合法以凹凸棒土为原料,合成了新型NH4＋-N吸附剂淀粉-g-丙烯酸/凹凸棒土,并进行了氨氮吸附对比实验。结果表明：凹凸棒土氨氮单位吸附量为4.243 mg/g;淀粉-g-丙烯酸/凹凸棒土氨氮单位吸附量为5.301 mg/g,吸附能力比未改性的凹凸棒土提高了25%。淀粉-g-丙烯酸/凹凸棒土的氨氮吸附过程比...     

Fluorescence excitation-emission spectroscopy with regional integration analysis for assessment of compost maturity

Composting of animal manures is believed as an alternative way for directly recycling them in farms, and therefore assessment of compost maturity is crucial for achieving high quality compost. Fluorescence excitation-emission matrices (EEMs) combined with regional integration analysis is presented to assess compost maturity. The results showed that the EEM contours of water-extract organic matter (WEOM) from immature composts exhibited four peaks at excitation/emission (Ex/Em) of 220/340 nm, 280/340 nm, 220/410 nm, and 330/410 nm, whereas EEM contour of WEOM from mature composts had only two peaks at Ex/Em of 230/420 nm and 330/420 nm. Pearson correlation demonstrated that peaks intensity rather than their ratios had a significantly correlation with the common indices assessing compost maturity, whereas the normalized excitation-emission area volumes (Φ_i,ns) from regional integration analysis had a stronger correlation with the common indices assessing compost maturity than peaks intensity. It is concluded that the Φ_i,ns from regional integration analysis are more suitable to assess the maturity of compost than the intensities of peaks. Therefore, the fluorescence spectroscopy combined with regional integration analysis can be used as a valuable industrial and research tool for assessing compost maturity, given its high sensitivity and selectivity.     

Effects of harvest regime and water depth on nutrient recovery from swine wastewater by growing Spirodela oligorrhiza

Harvest regime and water depth were investigated to determine their effects on nutrient recovery from swine wastewater by a Spirodela oligorrhiza system. The results show that harvesting less duckweed at shorter intervals favored nutrient removal and total biomass production. Harvesting 20% of duckweed twice a week led to 66.3 and 109.4% higher total nitrogen and total phosphorus removals, respectively, and a duckweed production of 20.0 g fresh biomass/m2 x d--39.6% higher than that of harvesting 80% of duckweed once every 4 weeks. The water depth of duckweed system was of great importance to total nutrient removal. At the water depth of 40 cm, total nitrogen and total phosphorus removals were 2.05 and 2.16 times higher, respectively, than those at the water depth of 10 cm. However, because of the larger amount of nutrients in a deeper system, it took a longer time for the nutrient concentrations to decrease.     

乡镇工业废水对农业环境影响的典型调查

选择较有代表性的宁波市郊慈镇作为典型,调查分析了铜业乡镇企业对周围农业环境的污染情况。调查结果表明,污染源附近水域水质铜含量为０．００９～８．４６１ｍｇ／Ｌ,超标率为４３．８％,锌为０．０２～５．９２ｍｇ／Ｌ,超标率为３７．５％。土壤中铜的含量为３３．１～３２６．２ｍｇ／ｋｇ,超标率为７２．２％。粮食中铜含量为２．１９～２４．２０ｍｇ／ｋｇ,超标率为３７．５％。     

曝气生物流化池生物强化处理高氨氮制革废水研究

以曝气生物流化池(ABFT)I艺为核心,通过投加高效菌酶添加剂(简称菌荆)的方法对高氨氮制革废水进行生物强化处理研究.结果表明,在菌剂投加量为0.4 kg/m3,总水力停留时间为32 h(其中生化处理段水力停留时间为29 h)条件下,菌剂投加10 d后氨氮的去除率可达80.2%,25 d后系统即可稳定运行;出水氨氮平均为4.8 mg/L,去除率为98.8%;出水COD平均为137 mg/L,去除率为76.4%.无机碳化合物和生长因子对硝化反应有促进作用,使氨氮的去除率提高约6.6%.该结果显示了ABFT工艺在处理高氨氮制革废水上具有明显优势.     

pH值控制MAP法脱氮进程的可行性研究

MAP沉淀法处理高NH₃-N废水,操作简便,处理效果好。本试验以NH₃-N浓度为1 000 mg/L的模拟废水为研究对象,研究结果表明,在Mg²⁺∶PO^3-₄∶NH⁺₄=1.2∶1.2∶1（摩尔比）、NaOH投加量为675 g/L的条件下NH₃-N去除率高达98%以上。试验选择出水pH作为控制反应进程的参数,并建立了出水pH与NH₃-N去除率之间的关系。通过调整NaOH投加量控制出水pH在7.5～8之间时,NH₃-N去除率最高,可达98%以上。X-衍射图谱及定量分析表明,沉淀物中MAP的纯度较高,具有一定的回收价值。     

Can SVM be used for automatic EEG detection of drowsiness during car driving?

This study aims to develop an automatic method to detect drowsiness onset while driving. Support vector machines (SVM) represents a superior signal classification tool based on pattern recognition. The usefulness of SVM in identifying and differentiating electroencephalographic (EEG) changes that occur between alert and drowsy states was tested. Twenty human subjects underwent driving simulations with EEG monitoring. Alert EEG was marked by dominant beta activity, while drowsy EEG was marked by alpha dropouts. The duration of eye blinks corresponded well with alertness levels associated with fast and slow eye blinks. Samples of EEG data from both states were used to train the SVM program by using a distinguishing criterion of 4 frequency features across 4 principal frequency bands. The trained SVM program was tested on unclassified EEG data and subsequently checked for concordance with manual classification. The classification accuracy reached 99.3%. The SVM program was also able to predict the transition from alertness to drowsiness reliably in over 90% of data samples. This study shows that automatic analysis and detection of EEG changes is possible by SVM and SVM is a good candidate for developing pre-emptive automatic drowsiness detection systems for driving safety.     

Does an energy efficiency label alter consumers' purchasing decisions? A latent class approach based on a stated choice experiment in Shanghai

In this paper we conducted a hypothetical choice experiment in Shanghai, China, to examine whether the China Energy Efficiency Label influences consumers' choices of air conditioners and refrigerators. A latent class approach was applied to observe both heterogeneities among the respondents and product brands. Our results suggested that consumers in Shanghai were well aware of the China Energy Efficiency Label and tended to pay more attention to products with such labels. In addition, air conditioners and refrigerators affixed with a hypothetical label that indicates saving in electricity bills compared with a standard model received significant preferences, which suggested that the more information manufacturers provide, the more their products would be preferred by consumers. Finally, weighted by class probability, the willingness to pay values for more energy efficient refrigerators were higher than those for more energy efficient air conditioners, implying that Shanghai consumers have greater incentive to pay more for appliances they use more frequently.     

科技信任、管理信任及其对公众水灾风险认知的影响——基于长江中下游的社会调查

信任和风险在一定程度上互为因果,两者通过认知行为决策及行为后果这一环节构建互馈关系。探索公众对社会减灾能力的信任及其对灾害风险认知的影响机制,有助于揭示灾害风险的潜在因素,调适风险认知与避灾行为,从而降低灾害风险。选取水灾发生频繁、强度大、防洪措施多样的长江中下游地区为研究区,运用随机抽样调查和入户访谈相结合的方式获取资料,研究公众的水灾科技信任和管理信任的水平、影响机制、动机-效应差异。主要结论有:①公众科技信任水平普遍高于管理信任。信任水平受到公众性别、年龄、灾害经历、城乡差异等因素不同程度的影响,信任具有区域共构的特点;②科技信任改变了公众水灾风险认知,加强了其灾害应对信心,降低了其对受灾风险的估测,对其避灾行为倾向影响显著,而管理信任对公众水灾风险认知及防灾备灾行为倾向的影响均不大;③信任的产生动机以认可减灾措施有用性为前提,科技减灾和管理减灾由于具有不同的减灾原理及作用时段,导致了公众的不同信任动机及其效应。