输氧抽气技术在垃圾填埋场治理中的关键参数试验研究

输氧抽气技术是基于好氧降解原理对垃圾填埋场中固体废弃物实施原位处理的先进环保技术。采用该技术对垃圾填埋场中固体废弃物减量化研究,总结了技术应用中的关键参数:有效影响半径,最佳真空度等。结果表明抽气流量大小与影响半径密切相关,抽气影响半径建议取20~25 m,抽气系统最优负压为20 k Pa,同时在技术应用过程中应保证垃圾场表层覆盖层的密封性能,尽量减少空气的渗入。输氧抽气技术在垃圾场的成功实施为同类型场地治理提供工程技术参考。     

6种苯系物对虾夷扇贝的生殖毒性作用

采用半静水式毒性试验,研究了6种苯系物(苯、甲苯、乙基苯、邻–二甲苯、间–二甲苯、对–二甲苯)对虾夷扇贝的生殖毒性作用。在水温(16±0.5)℃、盐度30.0、p H 8.0条件下,用0.5、2.5、12.5 mg·L-1的苯、甲苯、乙基苯、邻–二甲苯、间–二甲苯、对–二甲苯处理虾夷扇贝的精子、胚胎和幼体,观察6种苯系物对虾夷扇贝的精子活力、卵子受精率、胚胎延滞率、胚胎畸形率、孵化率、幼体畸形率的影响。同时通过透射电镜观察6种苯系物(2.5 mg·L-1)对虾夷扇贝精子超微结构的损伤作用。结果发现:不同浓度苯系物处理组与对照组(0.0 mg·L-1)相比,虾夷扇贝精子的运动时间、卵子受精率及胚胎孵化率显著降低;胚胎发育延滞率、胚胎畸形率和幼体畸形率显著增加为并与处理浓度之间存在显著的剂量—效应关系。以上结果表明实验浓度下,6种苯系物对虾夷扇贝具有较强的胚胎毒性和生殖毒性作用。通过电镜切片发现,2.5 mg·L-1的苯、甲苯、乙基苯、邻–二甲苯、间–二甲苯、对–二甲苯导致虾夷扇贝精子超微结构损伤,表现为:精子质膜断裂、部分溶解,线粒体质膜和内嵴断裂、部分溶解。苯系物对虾夷扇贝精子超微结构的损伤可能是影响其精子活力和降低卵子受精率的主要原因之一。上述结果为苯系物对海洋贝类的生殖毒性评价提供基础数据。     

神经网络与模拟退火算法结合的锅炉低NOx燃烧优化

对某600MW燃煤电站锅炉进行了多工况热态NO_x排放特性测量,在利用多层前向神经网络对该锅炉的NO_x排放特性进行建模的基础上,将神经网络模型与模拟退火全局优化算法相结合,实现了锅炉的低NO_x燃烧的优化,计算得到可获得低NO_x排放浓度的具体燃烧配风方案.文中对2种不同退火参数的模拟退火算法进行了比较,结果说明采用T₀=50K,α=0.6的参数可以获得较好的寻优效果.本文研究结果为实现大型电站锅炉低NO_x燃烧控制的在线优化技术打下了基础.     

Enhancing soil aggregation and acetamiprid adsorption by ecofriendly polysaccharides hydrogel based on Ca2+- amphiphilic sodium alginate

Soil aggregation plays an important role in agricultural production activities. However, the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management, resulting in the loss of water, fertilizers and pesticides in soil. At present, hydrogels have been widely reported to promote the formation of soil aggregation. In this paper, amphiphilic calcium alginate (ASA/Ca²⁺) was applied to promote the formation of soil aggregation and enhance pesticide retention. Initially, an ASA was obtained through the one-pot Ugi condensation (a four-component green chemical reaction). Then, ASA/Ca²⁺ hydrogel is prepared by Ca²⁺ cross-linking. The formation of soil aggregation was determined through the Turbiscan Lab Expert stability analyzer, Confocal Laser Scanning Microscope (CLSM), and Transmission Electron Microscope (TEM). And the effect of soil aggregation on acetamiprid environmental behavior was investigated by adsorption kinetics, adsorption isotherms, and leaching. The results shown that the three-dimensional network structure of ASA/Ca²⁺ hydrogel can promote the formation of soil aggregation. Aggregate durability index (ADI) was 0.55 in the presence of ASA/Ca²⁺ hydrogel, indicating that amphiphilic hydrogel can enhance the stability of soil aggregation. The adsorbing capacity of acetamiprid was 1.58 times higher than pure soil, and the release of acetamiprid only about 20% in the presence of ASA/Ca²⁺ hydrogel. These results would be helpful for the formation of soil aggregation and pesticides adsorption on soil aggregation. Thus, ASA/Ca²⁺ hydrogel is likely to improve soil quality, simultaneously it can minimize the mobility of pesticides in the agricultural system.     

Utilization of solidified phosphogypsum as Portland cement retarder

The utilization of the phosphogypsum (PG) as cement retarder is both an economical and an ecological approach to treat this solid waste. Cement using raw PG as retarder has two problems pressing for solution,namely, delaying the setting time and difficulty being fed into the cement mill. The soluble phosphates in PG behave as super-retarder and bring about retarding in the setting process of cement made with PG. Two types of solidified phosphogypsum (SPG) were prepared to solve those two problems. The strength and the water stability of the SPG were good enough to ensure that they may be conveyed easily and fed into the cement mill stably. The cements with SPG had a similar setting time and strength as cement made with natural gypsum (NG). The microstructure of two kinds of SPG were observed with SEM. During factory application of SPG, good techniques and economic benefits were obtained.     

Microbial functional genes reveal selection of microbial community by PAHs in polluted soils

This report shows an increase of PAH-related microbial functional genes with PAH concentration in soils. Adaptation of microbial communities to organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) is a crucial issue. However, there is little knowledge on mechanisms ruling microbial community selection. Here, we studied microbial functional genes in soils contaminated by PAHs. We used GeoChip, an advanced functional gene array for gene analysis. Soil PAH concentrations were measured and microbial functional genes were categorized. PAH-related microbial functional genes, bph, nah, nidA, phd, dfb, and qor, were quantitatively expressed. Total microbial functional genes and PAH-related microbial functional genes were compared with PAH concentration by cluster analysis and curve-fitting analysis. We found that the average abundance of PAH-related microbial functional genes increased from 0.13 to 0.33, whereas that of total microbial functional genes decreased from 0.22 to 0.10 when PAHs concentration increased from 1.01 to 164.28 mg kg^?1. It was also found that the classification of microbial community structure characteristics based on PAH-related microbial functional genes was closely similar to the classification based on PAHs concentration. Findings reveal that PAH stress promotes the dominance of PAH-related microbial communities.     

太湖水体中5种有机磷农药混合物生态风险评价

有机磷农药是一类广泛分布于我国水环境中的污染物,即使在水体中的污染水平处于规定“安全标准”之下,其联合暴露产生的风险仍有可能威胁水生生态安全。采用基于浓度加和模型与生物敏感度分布曲线的混合物风险商法,评价了太湖水体中敌敌畏、对硫磷、甲基对硫磷、马拉硫磷和乐果5种有机磷农药混合物产生的生态风险。结果表明：2003～2004年期间3个不同时期太湖水体中5种有机磷农药的混合物生态风险商(RQ_m )均大于1,有机磷农药混合物在2003～2004年期间对太湖水生生物构成了一定威胁。     

One-pot preparation of graphene oxide magnetic nanocomposites for the removal of tetrabromobisphenol A

A simple solvothermal method was used to prepare monodisperse magnetite (Fe₃O₄) nanoparticles attached onto graphene oxide (GO) sheets as adsorbents to remove tetrabromobisphenol A (TBBPA) from an aqueous solution. These Fe₃O₄/GO (MGO) nanocomposites were characterized by transmission electron microscopy. The adsorption capacity at different initial pH, contact duration, and temperature were evaluated. The kinetics of adsorption was found to fit the pseudo-second-order model perfectly. The adsorption isotherm well fitted the Langmuir model, and the theoretical maximum of adsorption capacity calculated by the Langmuir model was 27.26 mg?g^-1. The adsorption thermodynamics of TBBPA on the MGO nanocomposites was determined at 303 K, 313 K, and 323 K, respectively. The results indicated that the adsorption was spontaneous and endothermic. The MGO nanocomposites were conveniently separated from the media by an external magnetic field within several seconds, and then regenerated in 0.2 M NaOH solution. Thus, the MGO nanocomposites are a promising candidate for TBBPA removal from wastewater.     

巨灾定义与划分标准研究——基于近年来全球典型灾害案例的分析

近年来,全球受严重灾害影响的国家和地区频繁出现,导致大量人员伤亡和严重经济损失。巨灾作为区域经济社会可持续发展的主要障碍之一,各国政府以及科技、产业与社会各界人士予以高度重视。目前,国内外对巨灾的研究绝大多数集中于巨灾保险,虽有部分研究涉及到巨灾定义及划分标准,但因研究目的与学术背景不同,至今尚无相对公认的、统一的巨灾定义。对巨灾概念的由来和国内外目前的研究动态进行了较全面的综述,论述了突发性与渐发性巨灾的差异,结合近年来全球典型灾害案例,总结给出巨灾定义、划分指标与标准,并在此基础上对巨灾未来研究进行展望,提出了研究的关键问题并建议进行更深入的研究。旨在为完善区域灾害系统原理,进一步推动巨灾研究提供参考。     

番茄ARF4基因果实特异RNAi载体的构建及遗传转化

构建ARF4基因果实特异表达的RNA干涉载体,对转基因番茄果实进行初步分析,可为采用基因工程方法改良番茄果实品质做出新尝试.利用RT-PCR技术从番茄果实cDNA中扩增SlARF4基因全长,将番茄ARF4基因正反向重复序列片段导入到植物表达载体pBI121上,启动子是番茄果实特异表达的TFM7.将构建的ARF4基因果实特异RNA干涉载体pBI121-TFM7-A4Ri通过根癌农杆菌介导转入到野生型番茄中,进而对转化获得的植株进行了阳性鉴定.分别以转基因番茄和野生型番茄为材料,分析ARF4在果实中的表达水平,测定绿熟期果实叶绿素含量、果实的单果重量和果皮厚度.酶切证实pBI121-TFM7-A4Ri果实特异表达载体构建成功,而且,PCR检测也得到阳性转基因株.半定量RT-PCR分析显示,转基因番茄果实中ARF4的表达量明显低于野生型果实.转基因番茄果实的叶绿素含量、单果重量和果皮厚度都比野生型有提高.因此,ARF4果实特异表达的RNAi方法能够改良番茄果实品质.