铈钛掺杂促进铁氧化物低温SCR脱硝性能的机理

利用X射线晶格衍射（XRD）、N₂吸附和X射线光电子能谱仪（XPS）等对铈和钛掺杂后的铁氧化物晶相、孔隙结构及表面活性组分的分散度等物性进行表征分析,得到了铈和钛掺杂对铁氧化物低温NH₃-SCR脱硝性能的促进机理.结果表明：铈和钛掺杂会抑制铁氧化物中Fe₂O₃的结晶,细化其孔径,增大其比表面积和比孔容;铈掺杂会促使铁氧化物表面形成Ce⁴⁺/Ce³⁺氧化还原电子对;进一步掺杂钛会提高铁铈复合氧化物形成更多吸附氧,增强其表面低温催化氧化NO为NO₂的性能;且铈和钛掺杂增强了铁氧化物表面的吸附性能,尤其提高了对NH₃的低温吸附,从而促进了铁基氧化物催化剂的低温NH₃-SCR脱硝性能.     

近35年广东省区域灰霾天气过程的变化特征及突变分析

利用广东省86个地面观测站1980～2014年逐日能见度、相对湿度资料,在对“区域灰霾过程”与“单站灰霾过程”进行定义的基础上,分区域诊断典型灰霾天气过程（即连续三站3d及以上出现灰霾日的天气过程）,并对其长期变化趋势及特征进行分析.结果表明：广东省的灰霾过程主要出现在珠江三角洲、粤北及粤东个别地区,并以珠江口以西的珠江三角西侧最为严重.“区域灰霾过程”以日平均能见度在5～10km之间的过程为主,没有出现过日平均能见度低于2km的重度灰霾过程.各“区域灰霾过程”的特征有所差异：首先是各“区域灰霾过程”出现峰值的时间略有差异.尽管灰霾过程均主要出现在10月～翌年4月,但粤北和粤东、西两翼最多出现在冬季（12月～翌年1月）、春季次之,而珠江三角洲地区则最多出现在春季（3～4月）、冬季次之.其次是各“区域灰霾过程”变化趋势的差异.珠江三角洲地区和粤北地区灰霾过程变化趋势比较相似,在2008年以前总体呈增多趋势,珠江三角洲地区增势最为显著的时段是2000～2008年,而粤北地区则是1991～2011年;粤西地区灰霾过程在2000年以前变化都比较平稳,2004年开始快速增多;粤东地区的灰霾过程近35年来虽有小的波动,但总体变化不大,呈稳中略减的趋势.利用M-K法和滑动t检验的突变分析表明,珠江三角洲地区灰霾过程的增多是一种不连续的突变现象,发生突变的时间点是1986年;粤北地区灰霾过程则在1992～1994年出现了突发性增多的现象;粤西地区灰霾过程也在2001年发生了突变.     

Effects of bicarbonate and cathode potential on hydrogen production in a biocathode electrolysis cell

A biocathode with microbial catalyst in place of a noble metal was successfully developed for hydrogen evolution in a microbial electrolysis cell （MEC）. The strategy for fast biocathode cultivation was demonstrated. An exoelectrogenic reaction was initially extended with an H2-full atmosphere to enrich Ha-utilizing bacteria in a MEC bioanode. This bioanode was then inversely polarized with an applied voltage in a half-cell to enrich the hydrogen-evolving biocathode. The electrocatalytic hydrogen evolution reaction （HER） kinetics of the biocathode MEC could be enhanced by increasing the bicarbonate buffer concentration from 0.05 mol·L-1 to 0.5 mol· L-1 and/or by decreasing the cathode potential from -0.9 V to - 1.3 V vs. a saturated calomel electrode （SCE）. Within the tested potential region in this study, the HER rate of the biocathode MEC was primarily influenced by the microbial catalytic capability. In addition, increasing bicarbonate concentration enhances the electric migration rate of proton carriers. As a consequence, more mass H＋ can be released to accelerate the biocathode-catalyzed HER rate. A hydrogen production rate of 8.44 m3. m 3. d1 with a current density of 951.6 A. m-3 was obtained using the biocathode MEC under a cathode potential of - 1.3 V vs. SCE and 0.4 mol· L-1 bicarbonate. This study provided information on the optimization of hydrogen production in biocathode MEC and expanded the practical applications thereof.     

Rhodococcus sp. T3-1菌株降解乙草胺的特性

以乙草胺为唯一碳源,通过摇瓶培养研究了Rhodococcus sp.T3-1对乙草胺的降解特性.结果表明,菌株T3-1降解乙草胺的最适温度为37℃,且其在pH值6~10的范围内对100mg/L乙草胺的降解率均在96%~97%之间.该菌株在接种量为5%条件下,14h内可将200mg/L的乙草胺降解95.5%;乙草胺的降解速率与乙草胺初始浓度呈负相关,与菌株T3-1的初始接种量呈正相关.菌株T3-1还可以降解丁草胺,但不能降解丙草胺、异丙草胺和吡草胺.     

汽油对加油站从业人员心理与神经系统的影响

为了解汽油对加油站从业人员心理与神经系统的影响,对北京市中石化所属19家加油站的345名作业人员和管理人员进行职业健康体检,结合心理测试量表,对人员的睡眠及情绪情况进行调查。结果显示19家加油站工作场所空气中汽油的浓度均符合国家卫生标准。加油作业人员中有神经衰弱症状的占738%,管理人员中有神经衰弱症状的占366%。加油作业人员中,有652%的人存在状态焦虑,有640%存在特质焦虑。管理人员中,有350%存在状态焦虑,有350%存在特质焦虑。加油作业人员中,存在睡眠障碍或睡眠质量下降的占635%;管理人员中,存在睡眠质量下降的占312%。提示加油站作业环境可能会影响作业人员的心理状态和睡眠状况,应加强对加油作业人员的职业健康监护工作。     

道路交通突发事件分类与分级

根据道路交通突发事件的发生过程、发生机理及动用资源的不同,道路交通突发事件可分为原生型道路交通突发事件和衍生型道路交通突发事件;根据道路所指的范围不同,道路交通突发事件又可分为公路交通突发事件和城市道路交通突发事件。在国家层面对道路交通突发事件进行分级的基础上,提出二次分级的思路。并以市级公安交通管理部门负责应对的道路交通突发事件为例,确立以应急机构(及领导人)的应急协调能力为基础,综合考虑当量死亡人数、对城市道路交通的可能影响半径以及主要监控道路预计平均每车延误的二次分级标准。     

珠江三角洲地区气溶胶分档活化特性与闭合实验

使用SMPS与CCNC系统相结合,于2011年12月在广州番禺大气成分站开展了40~200nm气溶胶粒子的分档活化观测.活化率曲线和统计结果显示0.109%、0.20%、0.39%、0.67%四个过饱和比下临界干粒径Dmid依次为143.7,99.5,74.7,62.6nm;对应的截断粒径Dcut为171.9, 119.1, 90.2, 72.5nm.进一步分析表明,气溶胶粒子的活化能力主要受粒径控制,成分与混合状态的影响在活化临界位置附近最为显著.本次观测结果与华北地区和周边城郊地区相比,气溶胶活化能力较弱.闭合实验计算得到的CCN数浓度与观测值存在很好的相关性(R2=0.9477),计算值较观测值高约16%.考虑到仪器系统误差等因素,认为两者闭合良好.对CCN数浓度计算中使用的3个因子,即气溶胶数浓度NCN、气溶胶谱型NSD、活化率曲线ARSR进行了敏感性实验,结果显示各因子对CCN数浓度的影响程度存在如下关系:NCN> NSD> ARSR.     

Optimal parameters for Phanerochaete chrysosporium degradation of terephthalic acid wastewater

The optimal parameters for the degradation of pure terephthalic acid (PTA) wastewater by the white rot fungus Phanerochaete chrysosporium were investigated. The relative mathematical model, objective function equation, constraint equations, constraint conditions and computer program were established in the optimal method. The results showed that the optimal value of the reactor volume needed was 9798 m³. It could save 83.82% of the reactor volume, which was needed for the native bacterium YZ1. This optimal method is simple, useful and economical for average treatment plants. Using the optimal parameters and P. chrysosporium to design and operate the treatment process of PTA wastewater would increase the treatment efficiency and decrease the cost.     

Integrated effects of slope aspect and land use on soil nutrients in a small catchment in a hilly loess area,China

This study addressed the integrated effect of slope aspect and land use on soil nutrients in a loess hilly catchment in the western Loess Plateau of China. Soil samples were collected from five land-use types: wasteland, cropland, woodland, shrubland and abandoned cropland, at two depths (0–20 and 20–40 cm) in the middle slope position of both north-facing and south-facing slopes. Soil nutrient changes and the relationships between soil nutrients and slope aspect were investigated, based on statistical analysis and expert knowledge. Soil organic matter, total N, total P, nitrate nitrogen and available K of the 0–20 cm soil layer differed significantly between land uses and slope aspects. Soil nutrients in the north-facing slope were better than in the south-facing slope. Revegetation has an enrichment effect, especially on soil organic matter, total N, total P, nitrate nitrogen and available K. Planting of trees, shrubs and grasses could improve soil fertility and favours a policy of revegetation and sustainable land use in the hilly loess area of China. Conversion of slope farmlands into more sustainable land uses, such as shrubland or grassland is a cost-efficient way to achieve soil conservation and ecological restoration. Terracing and the use of agro-techniques for soil conservation, such as furrow-ridging tillage and leaving crop residues on fields, can increase the input of C to soils. Growing crops in rotation with alfalfa and beans could be a promising choice for the sustainability of agriculture and the environment.     

邵阳市林业有害生物防控现状及防控体系建设模式初探

邵阳市是湖南省四大林区之一,多年来,林业有害生物发生危害严重.该文简要介绍了该市林业有害生物防控工作现状,分析了存在的主要问题;作者结合近年来的工作实践,从监测预警、检疫御灾、应急控灾、森林培育、宣传教育等5个方面提出了建设林业有害生物防控体系的基本模式,并就防控体系建设方面做了相应的探讨.