不同开垦年限黑土温室气体排放规律研究

以东北黑土区荒地土壤(H)、开垦2 a(L)、30 a(S)和100 a(Y)土壤为对象,在25℃和60%WHC水分条件下,通过7 d的室内培养试验,研究了不同开垦年限黑土温室气体N2O、CO2和CH4的排放规律.结果表明,黑土开垦后理化性质发生了显著改变,进而影响了温室气体的排放.N2O排放量随开垦年限的增加而增加,开垦30 a和100 a土壤的N2O排放量显著高于荒地土壤.净硝化量和N2O排放量与土壤水溶性有机氮和粉粒含量呈显著正相关关系,与土壤pH和砂粒含量呈显著负相关关系.CO2排放量随开垦年限的增加而逐渐降低,开垦30 a和100 a土壤与荒地土壤差异显著.土壤有机碳和水溶性有机碳含量与CO2累积排放量呈显著正相关关系.好氧条件下,荒地土壤和开垦土壤在培养前4 d表现为对CH4的微量排放,然后表现为对CH4的微量吸收,开垦土壤的CH4排放量随开垦年限的增加而增加.不同开垦年限黑土可能因土壤pH、有机碳、水溶性有机碳含量以及土壤机械组成的差异而产生CO2和CH4排放的差异.     

双酚A对大豆、玉米和水稻叶绿素荧光反应的影响

双酚A(BPA)普遍应用在工业制成品中,因需求量递增而产生的环境安全问题引发各方关注.与BPA对植物生长影响的研究工作相比,BPA影响植物生长的机理的研究甚少.光合作用是植物生产的重要生理过程,可通过叶绿素荧光测定技术探测和分析.基于此,本文利用叶绿素荧光测定技术,研究了BPA对大豆、玉米和水稻幼苗叶绿素荧光反应的影响.结果表明,3.0 mg·L-1BPA可降低大豆和玉米初始荧光F0,增加原初光能转化效率F v/F m、实际光能转化效率ΦPSⅡ、电子传递速率ETR、光化学猝灭系数qP和非光化学猝灭系数qN,对水稻各荧光参数无影响,即3.0 mg·L-1BPA可改善大豆和玉米光合PSⅡ系统,增强光能吸收,提高光合电子传递和光能转化效率;6.0 mg·L-1BPA可增加大豆和水稻的ΦPSⅡ、ETR和qP,降低F0,除增加qN外不影响玉米的其它荧光参数,表明6.0 mg·L-1BPA能改善大豆和水稻光合PSⅡ系统,提高光能转化和电子传递效率;除10 mg·L-1BPA对水稻各荧光参数无显著影响及17.2 mg·L-1BPA增加玉米和水稻的qN外,10 mg·L-1和17.2mg·L-1BPA可增加3种作物F0,抑制其它各荧光参数,即高剂量BPA引起作物光抑制,PSⅡ中心受损,光能转化和电子传递效率降低.此外,对比3种作物荧光参数变幅可知,BPA对大豆各荧光参数的影响玉米水稻.总之,BPA对3种作物叶绿素荧光反应的影响在方式和效果上存在差异.     

库湾营养盐循环对三峡库区营养盐输运的影响:以草堂河为例

三峡水库蓄水后,库区众多支流下游形成库湾回水区,这些库湾回水区是库区水环境调整最为活跃的地区.为了探究支流库湾对于库区生源要素循环及物质通量的作用和意义,于2012年8月~2013年7月对草堂河库湾、相邻干流、支流上游水体中溶解态无机氮(DIN)、溶解态无机磷(DIP)、溶解态硅酸盐(DSi)的时空分布进行逐月现场观测.结果表明,草堂河库湾回水区营养盐的浓度与库区干流相近,二者的月变化趋势也高度一致.干流输入是库湾DIN、DIP、DSi的主要来源.草堂河库湾与干流连通性很好,干支流水体交换迅速且充分,其影响可到达库湾回水区的末端.春、夏季,干流输入的营养盐通过表层生产力在库湾截留,秋、冬季库湾中的营养盐释放并输送到干流.营养盐在库湾的这种循环过程,在一定程度上改变了库区干流不同季节营养盐输送的节律.库区支流库湾众多,其对干流物质通量的季节调配作用不容忽视.     

模拟月尘颗粒真空辐射条件下粘附力测试技术研究

目的研究适合于真空辐射条件下颗粒粘附力的测试技术。方法采用调研、分析和计算的方法建立颗粒物粘附力测试方法。首先调研分析大气条件下颗粒粘附力的测试方法,对比分析原子力显微镜测试方法、离心测试方法、静电测试方法、振动分离测试方法以及激光测试方法的适用性。结果现有测试方法并不适用于真空辐射条件下颗粒物粘附力的测试。针对该问题建立了基于颗粒运动的粘附力分析测试方法,通过该方法可获取颗粒带电量和粘附力,给出了基于该方法的试验系统和试验装置的初步设计。结论该测试方法可行,能够满足模拟月尘颗粒粘附力测试的要求。     

自动在线监测系统利用软件数据质控有效性研究

自动在线监测设备对排放的污染物进行实时监测,获取真实有效的监测数据。研究自动在线监测设备监测数据质量保证系统是污染源自动在线监控系统科学判断和分析环境问题的前提。软件系统是数据采集、记录和存储、传输、统计分析、自我识别、形成报表和报告的集成,也是监测数据质量保证的有效手段,通过设定“阈值”和“条件”．实现了监测数的自动甄别、纠错和报警。     

A/O MBR处理生活污水效率与菌群多样性的关系

采用缺氧/好氧膜生物反应器（A/O MBR）工艺处理生活污水,试运行了5种不同的工况以确定最佳工艺参数,利用变性凝胶梯度电泳（DGGE）技术研究缺氧池和好氧池（MBR）中细菌群落结构,分析出水水质与细菌种群多样性的关系.结果表明A/O MBR在水力停留时间（HRT）为12 h,污泥停留时间（SRT）为10 d,硝化液回流比为300%,污泥回流比为100%的条件下,对COD、氨氮、总氮有稳定良好的去除,平均去除率分别为96.4%、99.1%、75.8%;系统运行过程中,缺氧池和好氧池中菌群结构发生较大变化,同一工况下两池菌群的相似性通常大于50%,但缺氧池菌群多样性随工况变换而波动较大,好氧池菌群多样性随运行时间而逐渐丰富;缺氧池菌群多样性指数与反硝化效率成正相关关系.     

Synergetic analysis of springtime air pollution episodes over Gwangju, Korea

The characteristics of springtime aerosols,including their optical and microphysical properties,were analyzed for the months of March to May of 2009 in Gwangju(35.23°N,126.84°E),Korea.A high Light Detection and Ranging(LIDAR)-derived aerosol depolarization ratio(δ) of 0.25 ± 0.04 was determined on dust particles during the observation period.The?ngstr?m exponent values of the 440–870 nm wavelength pair(?_(440–870)) and single-scattering albedo at 675 nm(Ω_(675)) measured by a CIMEL sun/sky radiometer were 0.77 ± 0.19 and 0.95 ±0.01,respectively.The elevated dust layers reached a maximum elevation of 4 km above sea level.Anthropogenic/smoke particles that originated from highly populated/industrialized regions could be distinguished by their relatively smaller particle size(?_(440–870) ranged between1.33 and 1.36) and higher light-absorbing(Ω_(675) of 0.92 ± 0.01) characteristics.These aerosols are mostly distributed at altitudes 1.2 km.The root-mean-square deviation(RMSD) between the aerosol optical depth(AOD,τ) derived from LIDAR_((τ_(LIDAR))) and from the CIMEL sun/sky radiometer_((τ_(CIMEL))) varied with respect to the surface PM10 concentration.The RMSD between τ_(LIDAR) and τ_(CIMEL) was as low as 13% under lower PM_(10) concentration levels( 100 μg/m~3).In contrast,the RMSD between τ_(LIDAR) and τ_(CIMEL) increased three times(~31%) under high surface PM_(10) concentration levels(100 μg/m~3).These results suggest that the accuracy of τ_(LIDAR) is influenced by specific atmospheric conditions,regardless of its uncertainty.     

Re-emergence of a GII.4 Norovirus Sydney 2012 Variant Equipped with GII.P16 RdRp and Its Predominance over Novel Variants of GII.17 in South Korea in 2016

Noroviruses are major causative pathogen of nonbacterial acute gastroenteritis worldwide. Of the seven genogroups of noroviruses suggested recently, genogroup II genotype 4 (GII.4) had been the most common genotype identified in hospitalized patients in the last few decades. However, since the latter half of 2014, new variants of GII.17 have been reported as the main causes of outbreaks over GII.4 in East Asia and have also occurred in America and Europe. In this study, we monitored norovirus GII in coastal streams at South Gyeongsang province and South Jeolla province of South Korea from March 2015 to May 2016. Norovirus GII.17 capsid sequences were predominantly detected until September 2015 in water samples. However, we found that the number of positive cases of the norovirus GII.4 Sydney 2012 capsid sequence has been increasing since December 2015, overtaking that of GII.17 in 2016. The RdRp genotype of this predominant GII.4 variant in 2016 was identified as GII.P16. The emergence and predominance of the GII.4 pandemic capsid sequence harboring a different RdRp genotype suggested the potential for a future pandemic.     

Ca/Mg负载改性沼渣生物炭对水中磷的吸附特性

为处理含磷废水和实现沼渣资源化利用,将农业废弃物沼渣制备成生物炭(ZZs),通过Ca Cl2和MgCl2溶液对其进行浸渍改性,探究改性沼渣生物炭(CMZZs)对水体中磷的吸附特征.结果表明,改性后沼渣生物炭钙镁含量分别是改性前的1. 3和15. 4倍; SEM-EDS、BET、FTIR和XRD等测定表明,改性未改变生物炭表面化学官能团种类,但改性后生物炭出现新的衍射峰,与标准卡片对比后认为可能存在Mg(OH)_2、MgO等物质.当温度为303 K,溶液pH为9. 0时,CMZZs最大吸附量为76. 92 mg·g~(-1),是改性前的30. 1倍.等温吸附实验数据符合Freundlich方程,为多层吸附.吸附动力学分析发现,改性后生物炭在100 min内基本达到吸附平衡,吸附过程符合假二级动力学方程,以化学吸附为主.上述结果说明钙镁改性沼渣生物炭对于去除水中磷具有潜在价值.