土壤有机质对宁夏农业综合开发活动的响应

为深入分析宁夏农业综合开发活动对土壤有机质的影响,认识其对气候变化的适应意义,分别于北部平原灌区、中部干旱带和南部黄土丘陵区的3个农发项目典型示范点,选取典型用地、玉米地、未利用地3种土地利用类型,分析表层10～20 cm土壤有机质的变化规律。研究发现,生态区和土地利用类型是影响土壤有机质的重要因素,并存在极显著的交互作用。研究区土壤有机质在4.53～14.70 g·kg-1范围内变化,典型用地有显著改善,平均质量分数达10.40 g·kg-1。限定生态区条件下,北部平原灌区无论水稻还是玉米利用方式下,土壤有机质含量相对未利用地都出现显著提升,但是南部黄土丘陵区3种土地利用类型间并无显著差异,中部干旱带只有甘草地土壤有机质含量显著提升,幅度高达145%。限定土地利用类型条件下,3个生态区间典型用地土壤有机质出现显著差异,但是北部平原灌区和南部黄土丘陵区间未利用地以及玉米地表层土壤有机质差异并不显著。研究区农业综合开发活动对土壤有机质储存的作用以正效应为主,但是不同农业土地利用类型在不同生态区对土壤有机质的作用不尽相同。宁夏农业综合开发活动需要综合考虑生态区水土资源特征,选取适宜的农业土地利用类型,有效提升土壤有机质含量,积极应对气候变化。     

溶剂吸收法CO2捕集技术简述

CO2捕集是温室气体减排与利用的重要技术步骤之一。文章介绍了CO2捕集的气源及特点、捕集溶剂与填料的研究进展、能量集成和工艺优化以及化工流程模拟研究,提出该技术研究的重点与方向。     

提高区域生态环境质量综合评价水平的新思路--GIS与层次分析法的结合

区域生态环境质量综合评价涉及众多要素，同时又需要反映生态环境质量状况的空间格局。层次分析法在多要素综合评价方面具有独特优势，而GIS技术拥有强大的空间分析能力，将GIS与层次分析法相结合应用于江苏省生态环境质量综合评价，可以充分发挥两种方法的优势。首先，根据江苏省生态环境的基本特点确定生态环境质量综合评价的指标体系和基本评价单元，通过层次分析法，确定各评价指标的权重，计算出每个评价单元的生态环境质量综合指数和分指数；然后运用GIS技术，根据每个评价单元的质量指数和分指数，自动生成江苏省生态环境综合评价等级图；在此基础上，对江苏省生态环境整体及各不同侧面质量状况的空间分异规律进行分析和研究。结果显示，江苏省生态环境质量基本上由南向北逐渐降低，与自然环境状况的空间格局大体吻合，但局部地区有差异。表明自然条件对江苏省生态环境质量的空间分异起决定性作用，但社会经济和环境污染等因素同样对生态环境具有重要影响，在某些情况下，甚至可以成为决定因素，并在一定程度上改变生态环境的空间格局。     

对未遂事件发生原因重要度排序方法的探讨

介绍了灰色关联度计算的原理,并用灰色关联度方法对未遂事件的诱发原因进行了实例分析。     

Assessing the impact of fungicide enostroburin application on bacterial community in wheat phyllosphere

Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis (PCR-DGGE) were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the γ-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities (98%) to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application.     

生物倍增(Bio-dopp)工艺处理城市污水

生物倍增工艺(Bio-dopp)是通过可防堵塞的曝气系统、生物除磷系统、空气提升系统及快速澄清装置,将生物硝化、反硝化,释磷、吸磷,有机物氧化等各工艺全部协调在同一反应池内同时进行,并在池内设立澄清区(相当于二沉池)的一种新型城市污水处理工艺。其高效曝气设备确保低氧条件下微生物去除耗氧有机物(特别是在同一反应器内实现硝化反硝化)。同时保证高效搅拌效果,并且工艺稳定,维护方便。它省去了传统工艺的污泥回流泵房、二沉池等构筑物及配电、管道等相应设备。具有出水稳定、设备高效,投资与运行成本低,占地面积小等优点,有较强竞争力。     

Adsorption of atrazine by natural organic matter and surfactant dispersed carbon nanotubes

The aggregation and dispersion behaviors of carbon nanotubes (CNTs) can regulate the environmental spread and fate of CNTs, as well as the organic pollutants adsorbed onto them. In this study, multi-walled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) were surface modified with humic acids from di erent sources and with surfactants of di erent ionic types. The dispersion stability of surface modified CNTs was observed by UV-Vis spectrophotometry. The e ect of humic acid and surfactant dispersion on the adsorption of atrazine by CNTs was investigated by batch equilibrium experiments. Both humic acid and surfactant could e ectively disperse MWNTs, but not SWNTs, into stable suspensions under the studied conditions. Surface modified CNTs had a greatly reduced capacity for adsorption of atrazine. The inhibitory e ect of peat humic acid was relatively stronger than that of soil humic acid, but the two surfactants had a similar inhibitory e ect on atrazine adsorption by the two CNT types. Increases in surfactant concentration resulted in rapid decreases in the adsorption of atrazine by CNTs when the surfactant concentration was less than 0.5 critical micelle concentration.     

Diversity of methanotrophs in Zoige wetland soils under both anaerobic and aerobic conditions

Zoige wetland is one of the most important methane emission centers in China. The oxidation of methane in the wetland a ects global warming, soil ecology and atmospheric chemistry. Despite their global significance, microorganisms that consume methane in Zoige wetland remain poorly characterized. In this study, we investigated methanotrophs diversity in soil samples from both anaerobic site and aerobic site in Zoige wetland using pmoA gene as a molecular marker. The cloning library was constructed according to the pmoA sequences detected. Four clusters of methanotrophs were detected. The phylogenetic tree showed that all four clusters detected were a liated to type I methanotrophs. Two novel clusters (cluster 1, cluster 2) were found to relate to none of the recognized genera of methanotrophs. These clusters have no cultured representatives and reveal an ecological adaptation of particular uncultured methanotrophs in Zoige wetland. Two clusters were belonging to Methylobacter and Methylococcus separately. Denaturing gradient gel electrophoresis gel bands pattern retrieved from these two samples revealed that the community compositions of anaerobic soil and aerobic soil were di erent from each other while anaerobic soil showed a higher metanotrophs diversity. Real-time PCR assays of the two samples demonstrated that aerobic soil sample in Zoige wetland was 1.5 times as much copy numbers as anaerobic soil. These data illustrated that methanotrophs are a group of microorganisms influence the methane consumption in Zoige wetland.     

泥石流作用下夯土建筑灾变响应特征研究∗

探究泥石流对夯土房屋的破坏模式及其动力致灾特征,有利于推进研究山区房屋承灾体对泥石流的灾变机制,对提高灾害风险管理水平、指导山区防灾减灾工作具有重要意义。通过实地调研凉山喜德县基恩德沟火后泥石流,总结了泥石流对夯土房屋的破坏模式,分析了泥石流动力学特征,根据现场受损房屋实测数据进行三维建模,利用有限元分析方法,获取了夯土建筑的位移时程响应和应力时程响应,反演了夯土建筑承灾破坏过程,探讨了泥石流作用下夯土建筑灾变响应特征。结果表明：(1)泥石流对夯土房屋的破坏模式表现为：通过墙体干缩裂缝渗入室内淤埋房屋;冲刷墙体基础导致墙体倒塌;携带大石块冲毁建筑;(2)墙体受泥石流冲击破坏表现为冲击点压碎破坏、墙体内侧受拉破坏和墙角剪切破坏;纵墙损伤为泥石流冲毁山墙后进入室内沿门洞冲出时导致的第二次破坏;(3)夯土房屋整体性较差,裂缝的发展切断了应力的传递路径,有效保护了其他墙体;(4)夯土房屋在泥石流作用下率先破坏的区域为大石块撞击点、墙基和墙角等形状突变位置。为此,夯土房屋防护,可首先考虑加固墙基和墙体转角等应力突变位置。