Simulation of temporal and spatial change of N2O emissions in the Yangtze River Delta

A biogeochemical model(DNDC) is combined with a plant ecological model to estimate N2O emission from rice paddy fields in the Yangtze River Delta region. The model is driven by local meteorological, soil, and physiological data and is validated for 1999 and 2000 at a site in the region, which showed that the simulated N2O emissions agree fairly well with the observed data. This adds some confidence in the estimated N2O emissions during 1950 and 2000 in the Hangzhou Region. A significant correlation between the N2O emissions and the population for the Hangzhou Region is found, which is due to a combination of increased application of fertilizers and cultivated area.Such a correlation can not be established for the whole Yangtze River Delta region when the data of both urban and rural are as areincluded. However, when the data from the heavily urbanized areas are excluded, a significant correlation between population and N2O emissions emerges. The results show clearly that both the temporal and the spatial N2O emissions have significant positive relationship with population under traditional farming practice. These results have implications for suitable mitigation options towards a sustainable agriculture and environment in this region.     

长白山阔叶红松林空气N_2O浓度的垂直分布特征

在原始阔叶红松林测定空气N2 O的垂直分布 ,三次观测结果发现林冠高度处N2 O浓度比树干和林冠上方的背景值高 5 4 3% -74 % ,差异极显著。林冠外出现高浓度 ,树干处低浓度 ,表明N2 O是从林冠排放到周围空气中的。因此 ,本研究提供了植物在自然状态下能排放N2 O的证据 ,从而证明了森林生态系统中植物本身也是大气N2 O的排放源。     

大气N_2O的稳定氮同位素质量平衡探讨

地表释放源释放的N2 O均比对流层大气N2 O贫15N ,对流层N2 O的氮同位素质量由平流层回流的富15N的N2 O来平衡 ,若全球N2 O源汇质量估算结果是平衡的 ,则地表释放源对对流层N2 O的氮同位素质量的贡献量应与平流层回流的贡献量相等。本文根据全球N2 O释放源最近的年释放量估算值 ,在考虑土壤N2 O生成过程中的氮同位素分馏效应后 ,推论出全球N2 O释放源最近的年释放量估算值能使对流层大气N2 O稳定氮同位素质量接近于平衡。     

H2O2对载银TiO2光催化降解Aroclor1260的影响

光催化氧化法降解水中有机污染物是近来发展较为迅速的废水处理技术，以锐钛型载银TiO2为催化剂，在发射光谱波长为254nm，功率的15W紫外灯照射下，考察不同H2O2浓度对Aroclor1260的光催化降解的影响，结果表明：低浓度的H2O2对Aroclor1260的光催化降解有促进作用，而当H2O2的浓度高于30mol/l时，光催化降解受到抑制，而且这种影响对不同PCB单体化合物的效果基本一致。     

用亚硫酸钠处理硅钢含铬废水的实验研究

用亚硫酸钠为还原剂对硅钢含铬废水进行了试验研究.结果表明,当反应阶段和沉淀阶段溶液的PH分别控制在3～4和8～9,投加1.4倍理论量的亚硫酸钠,反应20min,沉淀2h,出水六价铬和总铬均可达到排放标准.同时还可制得重要的化工原料Cr2O3.     

NH_3的低温复相选择性催化氧化

采用Cu-Ag/Al2O3复合催化剂在低温下选择性催化氧化 NH3.实验结果表明,Ag/Al2O3 和 Cu/Al2O3分别具有高氧化活性和高 N2选择性的优点;一定负载量范围内,Cu-Ag/Al2O3复合催化剂既具有高氧化活性(介于Ag/Al2O3和Cu/Al2O3之间),又具有Cu/Al2O3的高N2选择性,当反应温度为280℃时,Cu5%-Ag5%/Al2O3对NH3的氧化率大于96%,N2选择性大于95%.催化剂表面上形成的Ag2O 颗粒及其大小是影响催化剂选择性的一个重要因素.     

微电解-生化工艺在硝基苯废水处理中的协同作用

采用微电解与生化工艺结合处理硝基苯废水。通过微电解提高废水的可生化性 ,使废水的BOD5 CODCr由 0 11提高至 0 2 6 ;利用H O工艺进行后续处理 ,在H柱水力停留时间为 2 0h ,O柱水力停留时间为 10h的条件下 ,废水的总CODCr去除率为 86 % ,硝基苯的去除率为 99%     

絮凝沉淀-H2O2/UV体系处理发制品废水的研究

研究了发制品废水经絮凝沉淀－H2O2／UV体系处理的可行性。结果表明，废水经处理后，COD去除率可达90％以上，色度去除率达100％，探讨了投药量、反应pH、反应时间等因素对COD去除率的影响，并比较了H2O2／F^2 、H2O2／UV、H2O2／Fe^2 ／UV三种体系的处理效果。     

Effect of TiO2 surface properties on the scr activity of Nox emission abatement catalysis

NOx emission abatement catalysts V2O5 supported on variousTiO2 including anatase, rutile and mixture of both have beeninvestigated with various physico-chemical measurements such asBET, NH3-TPD, NARP, XRD and so on, and the effect of TiO2 surfaceproperties on the SCR activity of V2O5/TiO2 catalysts was studied.It has been found that the TiO2 surface properties had strongaffect on the SCR activity of V2O5/TiO2 catalysts. The strongeracidic property resulted the higher exposure of active sites aswell as the higher SCR activity.     

概论N_2O大气浓度演变及其大气化学

N2 O在对流层中是长寿命的痕量温室气体 ;在平流层 ,它是破坏O3层主要痕量气体之一NO的生成源。本文主要综述了N2 O的大气浓度演变、大气寿命、对温室效应的贡献、大气化学等 ,着重探讨了可能存在的N2 O大气生成和消耗过程