间歇性饥饿对厌氧氨氧化菌混培物保藏特性的影响

厌氧条件下,采用4℃、4℃并每隔10 d换1次NO-2-N/NH+4-N浓度比为1.32的基质、4℃并每隔10 d换1次NO-2-N/NH+4-N浓度比为1.63的基质3种方法保藏厌氧氨氧化菌混培物,研究间歇性饥饿对厌氧氨氧化菌混培物保藏特性的影响.结果表明,间歇性饥饿对厌氧氨氧化菌混培物的危害大于长期性饥饿,且亚硝态氮浓度越高危害越大;另厌氧氨氧化菌混培物活性还与血红素c含量有直接相关性,无外界颜色干扰时厌氧氨氧化菌混培物颜色还可直观反映其活性和血红素c含量,且厌氧氨氧化菌混培物的颗粒结构及其富含的胞外多聚物能增强其抵抗外界不利因素的能力.在试验的5个月内,3种方法下的活性衰减速率均先快后趋于稳定,趋于稳定时的三者活性保留率分别为75.3％、70.8％、62.7％.     

亚热带流域氮磷排放与养殖业环境承载力实例研究

畜禽养殖业粪便排放已经成为我国农村地区主要的农业面源污染源之一,也是制约养殖业良性发展的主要瓶颈.本文以湖南省长沙县典型亚热带流域为研究单元,基于流域水环境定位观测、耕地氮(N)磷(P)消纳能力以及养殖业调查和土壤分析资料,初步分析了亚热带丘陵区的面源污染现状及畜禽养殖业的环境承载力.结果表明,研究区金井河流域134.4 km2范围内N、P年负荷分别为N 2.72 t·km-2和P0.11t·km-2,其中养殖粪便对水体总氮(TN)、总磷(TP)负荷的贡献率分别约为42.2％和62.0％.区内平均畜禽养殖密度为3.46 AU·hm-2(相当于流域内年出栏生猪24.39万头),显著高于现有化肥用量条件下流域的实际承载力1.13 AU·hm-2(相当于流域内年出栏生猪6.35万头),因此养殖密度过高是导致研究区水体NP负荷较高的主要原因.区内N、P盈余量分别为N 35.8 kg·hm-2、P 18.61 kg·hm-2.研究区基本不施用化肥条件下畜禽养殖业的最大环境承载力为7.26 AU·hm-2,在有机肥占合理施肥量30％条件下,当地畜禽养殖业的环境承载力为2.74AU·hm-2(相当于流域内年出栏生猪19.50万头).降低养殖密度、调整养殖业空间布局以及提高养殖废弃物的资源化利用率是防治当前面源污染的有效途径.     

Removal and transformation of organic matters in domestic wastewater during lab-scale chemically enhanced primary treatment and a trickling filter treatment

To find a simple and economical way for treating the domestic wastewater in small counties and towns, a process combining chemically enhanced primary treatment and a trickling filter (CEPT-TF, representing the physical and biological effects) was constructed and operated in laboratory conditions. The characteristic behaviors of dissolved organic matter in raw wastewater and effluents were examined during steady-state operation. Experimental results showed that the process of CEPT and TF in series was beneficial for the removal of hydrophobic and hydrophilic organics. Specially, the hydrophobic and aromatic materials could be preferentially removed in the CEPT unit, and the hydrophilic fraction in the TF. Structural changes of the organic fractions during the operation of the different units were also characterized via spectrum analysis.     

珠江三角洲印刷行业VOCs组分排放清单及关键活性组分

根据珠江三角洲地区印刷行业活动数据和不锈钢罐采样-气质联用技术,获取了印刷工艺VOCs成分谱,建立了该地区2010年印刷行业VOCs组分排放清单,研究了不同工艺排放的臭氧生成潜势. 结果表明:该地区2010年印刷行业VOCs排放总量达8591.26t,深圳、东莞、佛山排放量较大.凹印是印刷行业主要VOCs排放工艺,排放量达5762.01t;平印和凸印次之,分别为1954.01和37.82t.不同工艺排放的VOCs组分差异较大,平印工艺排放的VOCs成分中异丙醇含量最多(306.58t),其次为正庚烷(115.87t);苯和甲苯是凸印工艺排放的VOCs成分中含量最大的2种化合物,分别达5.58和4.83t;乙酸乙酯是凹印工艺排放的VOCs成分中的首要化合物,达2482.85t.凸印工艺排放的VOCs单位浓度臭氧潜势最大,达1.30μg/m3,平印和凹印较小,分别为0.89和0.72μg/m3,各工艺排放的含氧有机物对臭氧生成潜势的贡献均为最大.      

中国农田肥料N2O直接和间接排放重新评估

农田肥料(氮肥、复合肥、有机肥)是我国N₂O最大的排放源,其估计直接决定了排放总量的可靠性.为此,重新评估了中国农田肥料N₂O的直接和间接排放,选择2008年县域尺度活动数据、具有空间分异性的本土排放因子和参数来重新评估其排放规模、结构、空间格局及不确定性;通过与IPCC、EDGAR等国内外研究结果的对比分析,阐述该排放清单的可靠性和全面性.结果表明,2008年我国农田肥料N₂O排放总量为617.1 Gg(处于213.7~1149.2 Gg之间),其中,氮肥直接排放为458.8 Gg(74.5%),有机肥直接排放为121.0 Gg(19.6%),挥发沉降和淋溶径流造成的间接排放分别为28.0 Gg(4.5%)和9.3 Gg(仅占1.5%左右).排放集中在华北平原、东北的松辽平原、华中的淮河流域和四川盆地,以及华南的珠三角、雷州半岛和台湾地区的县(区、市、旗),主要分布在江苏(52.4 Gg)、四川(48.0 Gg)、湖北(43.2 Gg)、广东(40.8 Gg)、河南(39.6 Gg)、安徽(38.4 Gg)、湖南(31.6 Gg)、山东(28.9 Gg),其累积规模为全国总量的52%,其中,近50%的贡献源于164个县(区、市、旗).本排放清单具有更高的准确度和空间分辨率,而基于IPCC (2006)排放因子及参数的估计排放总量高估了约8.3%,对直接排放和间接排放则分别低估了12.5%和高估了330%.此外,在空间格局上还表现出高值区低估和低值区高估的特点,在491和1225个县(区、市、旗)的相对偏差超过了100%和50%,特别指出的是,间接排放在大部分县(区、市、旗)的相对偏差达到135%左右.     

基于退化轨迹的锂离子电池加速试验研究

针对锂离子电池长寿命、高可靠的特点,提出了使用恒定应力加速退化试验对其进行可靠性评估与寿命预测的方法。首先对锂离子电池进行FMEA分析,得出容量衰减是最常见的失效模式,并以温度作为主要的加速应力。其次,确定锂离子电池的加速退化模型和参数退化轨迹模型,并进行锂离子电池的加速退化试验设计。确定加速应力水平时,在锂离子电池参数退化轨迹的基础上,根据巴特利特检验统计量确定退化机理一致的边界应力。最后,基于伪寿命对锂离子电池的可靠性进行评估。     

Fe2O3 particles as superior catalysts for low temperature selective catalytic reduction of NO with NH3

Fe203 particle catalysts were experimentally studied in the low temperature selective catalytic reduction （SCR） of NO with NH3. The effects of reaction temperature, oxygen concentration, [NH3]/[NO] molar ratio and residence time on SCR activity were studied. It was found that Fe203 catalysts had high activity for the SCR of NO with NH3 in a broad temperature range of 150-270℃, and more than 95% NO conversion was obtained at 180℃ when the molar ratio [NH3]/[NO] = 1, the residence time was 0.48 seconds and 02 volume fraction was 3%. In addition, the effect of SO2 on SCR catalytic activity was also investigated at the temperature of 180℃. The results showed that deactivation of the Fe2O3 particles occurred due to the presence of SO2 and the NO conversion decreased from 99.2% to 58% in 240 min, since SO2 gradually decreased the catalytic activity of the catalysts. In addition, X-ray diffraction, Thermogravimetric analysis and Fourier transform infrared spectroscopy were used to characterize the fresh and deactivated Fe2O3 catalysts. The results showed that the deactivation caused by SO2 was due to the formation of metal sulfates and ammonium sulfates on the catalyst surface during the de-NO reaction, which could cause pore plugging and result in suppression of the catalytic activity.     

Overexpression of NADH oxidase gene from Deinococcus geothermalis in Escherichia coli

When using stable enzyme genes from a thermophile to create a biosensor in Escherichia coli, it is vital that these genes be overexpressed in order to provide a sufficient supply of enzymes. In this study, overexpression of the NADH oxidase (Nox) gene from the thermophile Deinococcus geothermalis was successfully achieved with the aim of creating a stable biosensor active at room temperatures. To do so, modification of 10 nucleotides, GAAATTAACT, upstream of the start codon of the Nox gene was necessary.     

2009—2011年包头市大气中颗粒物浓度分析

本文通过对内蒙古包头市2009—2011年PM10浓度和TSP浓度的测定,分析了大气中颗粒物浓度的含量状况。结果表明：2009年3月到9月份之间,出现6次沙尘天气,并且颗粒物浓度超过大气空气质量三级标准,其中最严重的一次PM10浓度达到1．147mg／m^3。PM10浓度一天的变化中,在下午5时和晚间10时达到两个峰值,分别是1．608mg／m^3和1．882mg／m^3。2010年中十一月份的TSP日平均浓度较高,比八月份TSP浓度高7倍。2011年春季空气中颗粒物污染较重,在沙尘天气发生期间,颗粒物浓度含量较高     

基于加热改性预处理废线路板的热力学作用过程研究

电子废物是固体废物环境管理的热点问题,而废线路板是电子废物的研究核心.废线路板是由铜箔、树脂和增强材料层压而成的复合材料,以破碎和分选过程相组合的机械物理方法是其资源化回收处理的主流技术,就如何提高破碎效果已成为机械物理技术发展面临的难题.研究提出了加热改性预处理的技术方法,用于废线路板结构物理改性和微观破坏,以提高破碎解离效率,其可实现金属与非金属的高度解离.基于改性处理技术,本文还分别从微观和宏观破坏力学角度,探究了加热改性处理机制.同时,结合ANSYS有限元热应力模型,对改性作用进行了理论分析.