Mixing regime shapes the community assembly process, microbial interaction and proliferation of cyanobacterial species Planktothrix in a stratified lake

Lake mixing influences aquatic chemical properties and microbial community composition,and thus, we hypothesized that it would alter microbial community assembly and interaction. To clarify this issue, we explored the community assembly processes and cooccurrence networks in four seasons at two depths(epilimnion and hypolimnion) in a mesotrophic and stratified lake(Chenghai Lake), which formed stratification in the summer and turnover in the winter. During the stratification period, the epilimni...     

SK标准静态混合器应用于压缩空气泡沫系统的可行性研究

引入工业上应用较成熟的SK标准静态混合器作为压缩空气泡沫灭火系统的气液混合结构,基于FLUENT数值模拟,研究了不同混合单元个数和长径比混合器的混合效果,从压损和混合均匀性两方面进行评价,选定5个混合单元,长径比为1:1的SK混合器为较优结构,并进行了试验验证,研究结果可以为混合室的设计提供参考。     

基于多层PDCA模式的动态集成化应急管理体系研究

应急管理体系是当今世界各国应对事故的重要手段之一,它的完善程度与事故后果的严重程度密切相关,这使得对应急管理体系的研究具有非常重要的现实意义。提出并构建了基于多层PDCA模式的动态集成化应急管理体系,该体系集动态性与集成化于一体,从现实需要的角度出发,解决了应急管理体系的现存问题,更为突出的特点是依据多层PDCA循环模式的运行方式,站在长期有效的高度保证了体系的全面持续改进。显然,无论是从逻辑还是从内容看,该体系都充分显示出动态集成、高效实用的优势。因此,在循环改进的运行方式下,应急管理体系的绩效必定螺旋上升。     

有机酸性工业废水铁曝气中和预处理探讨

对某有机有毒酸性工业混合废水,采用铁刨花曝气还原加中和絮凝沉淀法进行预处理研究,色度八方经达８５％以上,ＣＯＤ去除率达５０％,初步改善了混合污水的可生化性能,减轻了后续生化处理工艺的有机负荷。     

Sensitivity of the DERMA long-range Gaussian dispersion model to meteorological input and diffusion parameters

The Danish Emergency Response Model of the Atmosphere (DERMA) is described and applied to the first ETEX experiment. By using analysed low-resolution numerical weather-prediction data from the global model of the European Centre for Medium-range Weather Forecast (ECMWF) as well as higher-resolution data from two versions of the High Resolution Limited Area Model (HIRLAM), which are operational at the Danish Meteorological Institute (DMI), the sensitivity of DERMA to the resolution of meteorological data is analysed by comparing DERMA results with concentration measurements. Furthermore, the sensitivity to boundary-layer height and diffusion parameters is studied. These parameters include the critical bulk Richardson number, which is used to estimate the atmospheric boundary-layer height, the horizontal eddy diffusivity and the Lagrangian turbulence time scale. The parameters, which provide the best performance of DERMA, are 0.25 for the critical bulk Richardson number, 6×10³ m² s^-1 for the horizontal eddy diffusivity, and 3 h for the Lagrangian time scale. DERMA is much more sensitive to boundary-layer parameters when using high-resolution DMI-HIRLAM data than when using data of lower resolution from the ECMWF. Finally, the bulk Richardson number method of boundary-layer height calculation applied to DMI-HIRLAM data is verified directly against routine radiosondes released under the tracer gas plume. The boundary-layer height estimates based on analysed NWP model data agree well with observations, and the agreement deteriorates as a function of forecast length.     

生物炭对西瓜连作土壤真菌群落结构和功能类群的影响

为明确生物炭施入后对西瓜连作土壤真菌群落结构及功能类群的长期影响,以西瓜成熟期根区土壤为研究对象,借助Illumina NovaSeq高通量测序技术和 FUNGuild平台,探究不同用量（7.5、15.0和30.0 t·hm^-2）生物炭施用3 a后西瓜连作土壤真菌群落组成、多样性及功能的差异,并分析土壤环境因子与真菌群落结构间的关联性.结果表明,添加生物炭3 a后提高了土壤pH、有效磷、速效钾、全氮、有机质和阳离子交换量,降低了土壤碱解氮含量.生物炭的施用改变了西瓜连作土壤真菌群落结构,提高了土壤真菌的丰富度和多样性.所有土壤样本共获得922个OTU,子囊菌门、担子菌门、被孢菌门、壶菌门和球囊菌门为优势真菌类群,占土壤真菌群落的85.70 %~92.45 %,生物炭的施入降低了子囊菌门和担子菌门的相对丰度,增加了被孢菌门和球囊菌门的相对丰度;属水平上,随着生物炭的施用,被孢霉属和囊根壶菌属的相对丰度增加,而镰刀菌属相对丰度降低.Mantel检验分析发现,速效钾、碱解氮、有机质和pH是影响土壤真菌群落结构的主要环境因子.真菌主要营养类型为腐生营养型、病理营养型和共生营养型,中、高剂量生物炭处理显著降低了土壤中病理营养型真菌的相对丰度,显著增加了共生营养型真菌的相对丰度.综上,生物炭施用3 a后可改变西瓜连作土壤理化性质,促进土壤真菌群落结构和功能类群向健康有益方向发展.     

便携式红外气体分析仪的检测

介绍了便携式红外气体分析仪的检测方案。其检测项目与指标、检测方法可为各级环境监测站及行业监测站检测同类仪器时借鉴使用。     

Analysis for Chemical Characterization of Atmospheric Aerosols Application of X-ray Microprobe System and Double Thin Film Method

The X-ray microprobe system was applied to ultra trace characterization of single Kosa aerosols and non-Kosa aerosols simultaneously collected at Yasaka, Japan and TaeAnn, Korea. We demonstrated remarkable mass increase of heavy metals as well as soil components in individual particles during the Kosa event compared with the non-Kosa period at Yasaka. Backward trajectory analysis suggested that the Kosa samples were in the mixing state of mineral components and anthropogenic heavy elements. Double thin film method was applied to investigate the seasonal change of the mixing states of single sea-salt aerosols associated with chlorine loss due to the heterogeneous reactions between sea-salt particles and acidic gases. It was revealed that the percentages of both chloride-nitrate mixed particles and sulfate-nitrate ones were larger in wintertime than those in summertime and fraction of chloride-nitrate mixed particles increased with an increase of particle size. Comparison between the size-segregated bulk analysis and the single particle analysis demonstrated that remarkable chloride depletion occurred in coarse particles sampled on May in the former analysis, while chloride depletion in coarse particles was not marked in the latter analysis. The discrepancy attributes to the difference of the sampling time between both analyses because significant change of air mass route occurred during the bulk sampling after completion of the single particle sampling.     

烟气连续监测系统的相对准确度检测

阐述了HJ／T76—2001《固定污染源排放烟气连续监测系统技术要求及检测方法》标准中烟气连续监测系统的相对准确度计算和相对准确度计算中存在的问题。对存在问题中的重复性或复现性的假设、B类不确定度的忽略、标准分析方法平均值的采用和偏差检验进行了探讨。     

Diurnal variation of number concentration and size distribution of ultrafine particles in the urban atmosphere of Beijing in winter

Number concentration and distribution of airborne particles in the size range 5.6 to 560 um diameter were measured in Beijing for a 15-d period in winter 2005.Daily average number concentrations of nucleation mode(5.6-20 nm),Aitken mode(20-100 nm), and accumulation mode(100-560 nm)particles,and total particles were 17500,32000,4000,and 53500 cm~(-3),respectively.Average particle size distribution was monomodal with a mode diameter of about 40 um at night and bimodal with mode diameters of about 10 and about 40 nm during the daytime.New particle formation events,which were connected to diurnal variation of nucleation mode particles,were observed in more than half of the observation days.The events often started around 10:00-11:00 Chinese Standard Time (CST)and ended up after 3-4 h.Concentrations of Aitken and accumulation mode particles increased from midnight and reached their maxima at about 10:00 CST,and then decreased and became the lowest in the afternoon.Analysis of diurnal cycles in traffic volume and meteorological parameters revealed that the accumulation of the particles in Aitken and accumulation modes in the morning was influenced by formation of an inversion and increase in vehicle emission,and dispersion of such particles in the afternoon was associated with more effective vertical mixing and higher wind speed.