培养基中磷酸盐在GA1所产絮凝剂絮凝中的作用研究

考察了一株高效产絮凝剂微生物多粘类芽孢杆菌Paenibacillus polymyxa GA1(以下简称GA1)的发酵培养基以及培养基各组分的絮凝性.实验结果表明,培养基中K2HPO4、KH2PO4在CaCl2存在、pH值中性偏碱时对各种废水均有一定的絮凝性,在GA1所产絮凝剂(以下简称MBFGA1)絮凝废水的过程中起重要作用,且作用离子为PO43-和Ca2 ;这两种离子在pH值中性偏碱时能有效降低高岭土悬液的ζ电位绝对值到接近零,使胶体脱稳;PO43-和Ca2 形成絮状沉淀后,能网捕脱稳颗粒,进而在MBFGA1桥联作用下使颗粒结团沉降完成絮凝.发酵培养基虽有一定絮凝性,但效果不佳,处理后上清液颗粒平均粒径远大于发酵液处理,且絮体、泥饼性质差异大,不利于工业应用和后续处理.硫酸钡亦有一定的助凝效果,但因沉淀本身性质差异,其效果劣于磷酸钙.     

培养基种类和培养条件对白腐真菌生长和产酶特性的影响

以白腐真菌(Phanerochaete chrysosporium)为研究对象,比较了该菌种在人工合成培养基和天然培养基中的生长和产酶特性,考察了竹子浸出液,pH,载体和抗生素等对白腐真菌在天然培养基中生长和产酶特性的影响.结果表明,天然培养基中白腐真菌的生物量、菌丝小球直径和木质素过氧化物酶(LiP)活性均大于人工培养基.以天然培养基为基础培养基,加入竹子浸出液可以促进白腐真菌的生长和提高木质素过氧化物酶活性;较低pH(4.5)条件下菌丝小球直径较小;载体的加入使得菌体以附着形式生长;抗生素两性霉素B对白腐真菌的生长和产酶的影响存在阈值,当ρ(两性霉素B)超过50　mg/L时,白腐真菌的生长和产酶受到明显的抑制.      

混凝土生态膜挂膜实验研究

将水泥、碎石、粉煤灰及活性材料CRLT-1等制作的透水混凝土生态膜在渠式反应器中进行挂膜实验,通过实验对2种挂膜方法进行了比较,对2种挂膜方法下填料上的生物量和生物活性及反应器对COD和NH3-N等指标的去除情况进行了测定和分析。结果表明,逐渐增加进水流量的循环挂膜法可以加快反应器启动,10d后COD的去除率稳定在69%左右,启动时间少于直接采用设计流量进水的循环挂膜法,2种情况下生物活性在4.19～4.85mgO2/g·h之间。     

活性污泥-生物膜一体化反应器处理生活污水性能研究

针对中小城镇污水处理的特点开发了活性污泥-生物膜复合一体化反应器,该反应器实现了反应区和沉淀区一体化,综合了活性污泥法和生物膜法的优点,具有运行稳定、占地面积少、基建投资低、管理方便的优点,并具有较好的去除有机物和脱氮除磷能力.     

Multi-metric evaluation of the models WARM,CropSyst, and WOFOST for rice

WARM (Water Accounting Rice Model) simulates paddy rice (Oryza sativa L.), based on temperature-driven development and radiation-driven crop growth. It also simulates: biomass partitioning, floodwater effect on temperature, spikelet sterility, floodwater and chemicals management, and soil hydrology. Biomass estimates from WARM were evaluated and compared with the ones from two generic crop models (CropSyst, WOFOST). The test-area was the Po Valley (Italy). Data collected at six sites from 1989 to 2004 from rice crops grown under flooded and non-limiting conditions were split into a calibration (to estimate some model parameters) and a validation set. For model evaluation, a fuzzy-logic based multiple-metrics indicator (MQI) was used: 0 (best) ≤ MQI ≤ 1 (worst). WARM estimates compared well with the actual data (mean MQI = 0.037 against 0.167 and 0.173 with CropSyst and WOFOST, respectively). On an average, the three models performed similarly for individual validation metrics such as modelling efficiency (EF > 0.90) and correlation coefficient (R > 0.98). WARM performed best in a weighed measure of the Akaike Information Criterion: (worst) 0<wk<1$0<w_k<1$ (best), considering estimation accuracy and number of parameters required to achieve it (mean wk=0.983$w_k=0.983$ against 0.007 and ∼0.000 with CropSyst and WOFOST, respectively). WARM results were sensitive to 30% of the model parameters (ratio being lower with both CropSyst, <10%, and WOFOST, <20%), but appeared the easiest model to use because of the lowest number of crop parameters required (10 against 15 and 34 with CropSyst and WOFOST, respectively). This study provides a concrete example of the possibilities offered using a range of assessment metrics to evaluate model estimates, predictive capabilities, and complexity.     

电厂筒仓安全惰化保护装置的研制运用

贮煤筒仓的安全性能关系着电厂的安全运行,为解决筒仓可燃气体浓度增高而导致爆炸问题,可将惰性气体氮气通入筒仓内稀释和置换可燃气体。分析了电厂筒仓安全惰化保护系统的配置及运行情况,为电厂筒仓安全惰化保护装置设计和应用提供参考。     

双层多孔隙沥青路面吸音降噪有限元分析

针对单层多孔隙沥青路面容易阻塞的问题,提出双层多孔隙沥青路面结构形式,采用有限元的方法,应用空气介质和吸声结构的声一固耦合模型,通过大型商用软件ABAQUS对多孔隙沥青路面吸声结构的吸声性能进行数值仿真模拟,分析了双层多孔隙沥青路面中空隙率组合以及厚度组合下的降噪特性,据此提出适宜的双层多孔隙沥青路面结构参数,计算结果表明双层多孔隙沥青路面结构,当上层空隙率为10％,下层空隙率为25％,上层厚度为2cm,下层厚度为4cm时,吸声效果较好。结论可为双层多孔隙沥青路面的应用提供理论基础。     

路堑施工中的爆破设计及安全对策

路堑施工中的爆破在我国目前的工程爆破中占很大的比例,施工中存在很多安全隐患,一旦发生事故,将会导致人员伤亡和财产损失.针对具体的路堑工程,选择合理的爆破设计参数,设计爆破网络,进行爆破施工的设计,然后确定爆破方案,进行安全校核,并运用安全评价的方法辨识施工中存在的危险有害因素,提出适当的合理的安全对策措施.     

In vivo and in vitro metabolism of tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), by the freshwater planarian, Dugesia japonica

Cigarette smoke is a risk factor for human health, and many studies were conducted to investigate its adverse effects on humans and other mammals. However, since large amounts of cigarette products are produced and consumed, it is possible that tobacco chemicals can end up in aquatic environments through several routes, thus influencing aquatic organisms. In this study, the presence of tobacco-specific nitrosamine (TSNA), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), in aquatic environment was demonstrated. Since toxic effects on and distribution patterns of tobacco chemicals in aquatic organisms were rarely studied, after results of an acute toxicity pretest were obtained, experiment was conducted to investigate the bioaccumulation pattern of NNK and distribution patterns of its metabolites, mainly 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), in NNK-treated freshwater planarians, Dugesia japonica. Results from in vivo and in vitro studies showed that NNK was readily converted to NNAL through the carbonyl reduction in bodies of NNK-treated planarians. Tissue concentrations of both chemicals increased in time- and dose-dependent manners. Furthermore, we examined the end products of NNK/NNAL α-hydroxylation in NNK-treated planarians, but only 1-(3-pyridyl)-1,4-butanediol was detected, suggesting that NNK metabolism in planarians partially differs from that in mammalian systems. This is the first report on NNK metabolism in an aquatic organism and can be used as a foundation for developing freshwater planarians as a new in vivo model for the study of NNK toxicology in the future.     

Polymer coating of copper oxide nanoparticles increases nanoparticles uptake and toxicity in the green alga Chlamydomonas reinhardtii

Copper oxide nanoparticles (CuO NPs) are frequently used in a polymer-coated form, to be included in paints or fabrics for antimicrobial properties. Their application in antifouling paints may lead to the contamination of aquatic ecosystems. However, the toxicological risk of NPs in the environment is hard to evaluate due to a lack of knowledge on the mechanisms of NP interaction with biological systems. In this study, we investigated the effect of polymer coating on CuO NP toxicity in the green alga Chlamydomonas reinhardtii by comparing bare and polymer-coated CuO NPs prepared from the same CuO nanopowder. Both CuO NP suspensions were toxic to C. reinhardtii after 6 h treatment to concentrations of 0.005-0.04 g L⁻¹. Bare and polymer-coated CuO NPs induced a decrease of Photosystem II activity and the formation of reactive oxygen species. Polymer-coated CuO NP was found to be more toxic than the uncoated CuO NP. The higher toxicity of CS-CuO NP was mainly associated with the increased capacity of polymer-coated CuO NP to penetrate the cell compared to bare CuO NPs. These results indicates that the high toxicity of polymer-coated CuO NPs in algal cells results of intracellular interactions between NPs and the cellular system.