等离子体发生区工作时发射特定光谱的研究

介绍了2种不同等离子体发生区和不同测量距离对等离子体发生区沿面蓝光中紫外光的波长和相对光强的影响,所测的臭氧发生量大的等离子体发生区的紫外光的相对光强高,测量距离与相对光强呈指数关系,并且等离子体发生区沿面蓝光具有光催化作用.     

Economic assessment of the negative impacts of ozone on crop yields and forest production. A case study of the estate Ostads Säteri in southwestern Sweden

Ground level ozone concentrations, in combination with the prevailing climate, at the estate Ostads S?teri in southwestern Sweden were estimated to reduce the yield of wheat and potato ranging between 5% and 10%. Occasionally, in years with the highest ozone concentrations and/or climatic conditions favoring high rates of ozone uptake to the leaves, yield loss levels above 10% may occur. Based on simple extrapolation, these ozone-induced reductions of crop yields at Ostads S?teri represent a potential total annual yield loss in Sweden in the range of 24.5 million Euro for wheat and 7.3 million Euro for potato, respectively. A simulation of forest growth at Ostad S?teri predicted that prevailing mean ozone exposure during 1993-2003 had the potential to reduce forest growth by 2.2% and the economic return of forest production by 2.6%. Using this value for extrapolation to the national level, the potential annual economic loss for Sweden due to negative impacts of ozone on forest production would be in the range of 56 million Euro (2004 prices).     

倒置A2/O污水处理工艺的特点及应用实例

传统A²/O工艺在保证脱氮效果的同时除磷效果往往不佳。在充分分析传统A²/O工艺的基础上，提出了将缺氧池置于厌氧池前面，厌氧池后设置好氧池的分点进水倒置A²/O工艺。某污水厂的现场试验表明，在COD去除能力与常规A²/O工艺相当的情况下，倒置A²/O工艺的脱氮除磷功能明显优于常规A²/O工艺。     

Surfactant solubilization of hydrophobic compounds in soil and water

The soil/water partition coefficient (K_d) of hexachlorobenzene (HCB) ranged from 220 1/kg to 1800 1/kg for eight soils having a wide range of physico-chemical properties. K_d normalised to soil organic carbon (K_oc) was found to be 28000 ± 4800 1/kg. Anionic surfactant dodecylsulphate (DS) present at concentrations above the critical micellar concentration (CMC) caused reductions in the apparent soil/water partition coefficient (K_d ^*) in the range of 3–26 times for most soils and up to 36–91 times for sandy soils. Below CMC, at environmentally relevant surfactant concentrations, K_d ^* was reduced by a factor of 1–13. For clay and calcareous soils significant adsorption/complexation/precipitation of DS occurred. At the lowest DS concentration this produced a two-fold increase in K_d ^*. At increasing DS concentrations this effect was shielded by the solubihzing effect from DS. Monomer (K_mn) and micellar (K_mc) surfactant/water partition coefficients for HCB were determined to be, 980 ± 190 1/kg and 21000 ± 1600 1/kg, respectively.     

厌氧折流板反应器处理硝基苯废水的研究

采用厌氧折流板反应器(ABR)中温处理含硝基苯废水,研究了工艺条件和硝基苯的降解特点.试验结果表明:在进水COD浓度为2088 mg/L,硝基苯浓度为16.8 mg/L,反应温度为35℃,停留时间为24 h条件下,ABR能有效处理硝基苯废水,COD去除率为86.4%,硝基苯去除率为91.1%;在厌氧条件下,硝基苯降解为苯胺,但苯胺很难再进一步分解;硝基苯的去除历程推断为先吸附后分解.     

Comparison of biodegradation of surfactants in soils and sludge-soil mixtures by use of 14C-labelled compounds and automated respirometry

The biodegradability of dodecyl benzene sulphonate (LAS), nonylphenol-di-ethoxylate (NP2EO) and tridecyl-tetra-ethoxylate (LAE) in soil was examined by use of 14C experiments at two concentrations (10 and 400 mg/kg). Increasing the concentration of test chemical from 10 to 400 mg/kg resulted in a decrease in the relative maximum mineralization rate and an increase in the estimated lag times of a factor of approximately 3.5. In sludge-amended soil, the highest expected environmental concentration (just after sludge application) will be around 10 mg/kg for linear alkylbenzene sulphonate (LAS), while the concentration of NP2EO and linear alcohol ethoxylates (LAE) will be much lower. However, when using a respirometric method it is necessary to use a higher concentration of test substance in order to detect biodegradation. In our experiment, amendment with anaerobically digested sludge resulted in a decrease in the mineralization of LAS, NP2EO and LAE for all soils. Respirometric experiments were carried out at 400 mg/kg and could be used for estimation of biodegradation potential of LAS, NP2EO and LAE in soil and sludge-amended soil. For LAS, the results obtained from the respirometric experiments were similar to the results obtained in the 14C experiments, whereas NP2EO and LAE showed a faster degradation in the respirometric experiments.     

深圳大学城园区典型OVOCs污染特征与来源解析

采用质子转移反应质谱仪（PTR-MS）对深圳大学城园区2017年不同季节（分干湿两季）的6种典型OVOCs和其他非甲烷烃类（NMHCs）进行连续在线监测,分析其干湿季的浓度特征与日变化规律,并应用光化学龄的参数化方法开展OVOCs的来源解析.结果表明,在观测的6种OVOCs中,甲醇的平均浓度最高,达10×10^-9~12×10^-9,其次是乙酸、丙酮和乙醛,约2~5×10^-9,甲酸和丁酮的含量最低,仅1×10^-9~2×10^-9.通过日变化观察到的OVOCs湿季峰值浓度时间明显早于干季,乙醛表现出与臭氧（O₃）相似的日变化特征,揭示了其可能存在二次来源;甲醇和丁酮的峰值浓度时间均早于O₃,可能存在重要的一次排放源.采用光化学龄模型解析出日间污染物来源比例：在污染较重的干季,甲醇、乙醛、丙酮和丁酮的人为一次源占主导,甲酸和乙酸的二次源是主要贡献者;在较清洁的湿季,天然源成为乙醛、丙酮、丁酮、甲酸和乙酸的主要来源.     

浐河流域水-土-植物硝酸盐和氮同位素组成及氮源示踪

本文对关中浐河流域河水-土壤-植物的硝酸盐和氮同位素组成进行调查,并与前期对浐河河水氮同位素的结果对比。研究表明：从浐河上游至下游,土壤NO₃^?-N含量表现出：农耕区（43.5 mg???kg^?1）>森林区（3.25 mg???kg^?1）>城市区（0.63 mg???kg^?1）;土壤δ¹⁵N-NO₃^?值表现出：农耕区（18.1‰）>城市区（?1.5‰）>森林区（?5.8‰）;不同的土地利用类型是让其产生变化的重要原因。浐河河水NO₃^?-N含量（3.2?—?6.4 mg???kg^?1）及δ¹⁵N-NO₃^?值（?1.4‰?—?2.1‰）均表现出下游高于上游。相对于前期对浐河河水氮同位素的研究,发现上游和中游水体NO₃^?-N含量整体呈上升趋势,而下游地区NO₃^?-N含量有所下降。结合河流δ¹⁵N-NO₃^?的空间分布特征可以看出源头日渐发达的旅游业和中游农业的发展对水体的污染加重,而下游工业污染的治理效果明显。植物氮同位素变化范围在?4.6‰?—??2.1‰。对浐河周边水-土-植物的氮同位素组成特征和变化研究可以为浐河流域的生态评价和治理提供一定的理论依据。     

不同营养环境下棕鞭藻共栖细菌的群落结构比较

微藻富含油脂,可以用作合成生物柴油的原料,被认为是最具发展前景的生物质能源.微藻的光合培养体系往往是非纯培养体系,现有研究更多地关注微藻生物量的积累及其对废水环境的净化效果,而对体系中广泛存在的共栖细菌缺乏全面深入的认知.本文通过对棕鞭藻共栖细菌的16S rDNA基因进行高通量测序分析,研究棕鞭藻（Ochromonas）在生活废水、BG11及Glu+BG11（BG11中添加10 g·L^-1葡萄糖）3种不同营养环境中共栖细菌的群落结构差异,进而阐明有机物及复杂废水环境对微藻共栖细菌群落结构的影响效果.结果表明,生活废水、BG11及Glu+BG11 3种营养环境中共栖细菌群落结构存在显著差异,生活废水体系中生物多样性显著高于BG11及Glu+BG11体系,生活废水中共栖细菌香浓（Shannon）多样性指数高达4.32,其次是BG11及Glu+BG11,Shannon指数分别为2.13、1.54.从共栖细菌群落的组成上看,3种营养环境中优势菌属差异显著,生活废水中优势菌属有芽殖杆菌属（Gemmobacter）、鞘脂单胞菌属（Sphingomonas）及玫瑰球菌属（Roseococcus）,相对丰度分别为14.46%、14.9%、14.54%,其中,芽殖杆菌属只在生活废水中有较高丰度.BG11中寡养单胞菌属（Stenotrophomonas）与玫瑰球菌属的丰度分别高达26.86%、51.03%.Glu+BG11中寡养单胞菌属较BG11中显著增加,达到82.41%,而玫瑰球菌属较生活废水及BG11中则明显降低,菌群丰度仅为6.2%.对比3种营养环境,玫瑰球菌属均具有较高丰度,是棕鞭藻良好的共生菌.     

基于机器学习和卫星遥感的PM2.5/10 空间连续分布反演方法研究

在过去的几十年里,快速的经济发展以及工业化、城镇化进程加速使得中国的资源环境承担的压力不断加大。作为影响空气质量的首要污染物,PM_2.5和PM₁₀（记为PM_2.5/10）直接影响着广大人民群众的身体健康。因此,针对PM_2.5/10浓度进行遥感反演研究,对环境监测和控制改善全国空气环境质量具有重要的意义。近些年来,随着对近地面PM_2.5/10浓度研究的不断深入,基于遥感影像数据进行PM_2.5/10浓度的反演方法也日益增多。本文利用Google Earth engine（GEE）平台获取了海量的Landsat 8 OLI遥感影像数据,并结合气象信息、空间特征等参数,采用机器学习中常用的多层映射反向传播神经网络构建了波段反射率与PM_2.5/10浓度之间的反演模型,以获得PM_2.5/10在研究区域的连续分布。为了提高基础PM_2.5/10反演模型的反演精度,还从影响因素和前溯时间两个维度出发,探寻了模型的最优化输入参数组合,并最终实现了对PM_2.5/10浓度的精准反演。以北京市地区为例,模型的PM_2.5和PM₁₀的反演精度R²分别达到0.814和0.796,均方根误差RMSE分别为19.21 μg?m^?3和28.31 μg?m^?3。鉴于该反演结果具有较高的准确性和可靠性,本文所建立的方法模型为研究PM_2.5/10在空间上的连续分布特征提供了新的思路和方法,具有较为重要的科研意义与广泛的应用价值。