A model for tropospheric multiphase chemistry: application to one cloudy event during the CIME experiment

A multiphase box model for a remote environment of the troposphere has been developed with an explicit chemistry for both gas and aqueous phase. The model applied to a set of measurements performed by Voisin et al. (2000) during the European CIME experiment for a cloud event on 13th December 1997 at the top of the Puy de Dôme (France). The results of the simulation are compared to the measurements in order to follow the evolution of the ambient chemical composition as a function of the pH and of the varying water content. After verifying that the model retrieves the main features observed in the behavior of species in the cloud droplets, a detailed analysis of the simulated chemical regime is performed. It essentially discusses the sources and sinks of radical in aqueous phase, the relative importance of the oxidation pathways of volatile organic compounds by the main radicals and the conversion of S(IV) into S(VI) which seems to be influenced by the presence of peroxonitric acid, HNO₄, in aqueous phase in the environmental conditions that are considered with low H₂O₂. These numerical results are then compared with the theoretical study from Herrmann et al. (2000), who proposed a slightly different mechanism, including C2 chemistry and transition metal chemistry whereas they neglect some reaction pathways, such as the one involving OHCH₂O₂ radical. This double confrontation between model results and both real experimental data and numerical results from Herrmann et al. (1999c) underlines limitations of such modeling approach that does not include any dynamical or microphysical coupling but also demonstrates its capability to identify the main oxidants or reactants in aqueous phase in real environmental conditions more realistic than a purely theoretical approach. The originality of this study resides in the explicit and exhaustive ways the chemical reactions are treated in aqueous phase and in a first attempt to compare such a detailed chemical scheme to real environmental conditions.     

环境空气监测中NO_x、SO_2空白值的研究

本文研究了惠州市市区环境空气监测中氮氧化物、二氧化硫的现场空白值与室内空白值的差异,得出了二氧化硫测定的两种空白值相差无几,氮氧化物测定的两种空白值相差较显著的结论。提出了在计算环境空气氮氧化物浓度时,扣除现场空白值是消除分析误差的一个不可忽视的环节。讨论了现场空白值受环境条件（气温、光照强度等）影响的情况     

基于Copula函数的茶园土壤铜锌空间协同效应研究

揭示茶园土壤Cu、Zn空间协同效应对有效预防和治理土壤Cu、Zn污染,保障茶叶品质具有十分重要的作用。论文以江浙两地典型茶叶种植区为研究区,运用Copula函数对土壤Cu、Zn含量协同关系进行模拟、Kriging/IDW插值法进行空间估计、标准差椭圆模型进行空间效应分析。结果表明：1）研究区茶园土壤Cu、Zn含量二元频率直方图呈“J”型,具有上尾相关、下尾渐近独立的特征,其上尾相关系数λup及Kendall、Spearman秩相关系数分别为0.345 4、0.273 5、0.396 0,表明二者具有显著的正向相关性,建议加强土壤Cu、Zn含量监测,提升预警,避免复合污染;2）土壤Cu、Zn含量整体水平协同程度较高,局部因不同主导因子影响协同程度较低,应强化土壤Cu、Zn污染全域协同治理及局地因情施策的效果;3）Copula函数、Kriging/IDW估计以及标准差椭圆模型测算结果能相互印证,3种方法结合可更全面客观地反映两者的空间协同效应,为土壤Cu、Zn污染防治提供参考依据。     

圆管压入扩径内径变化分析

分析了圆管压入扩径时内径变化的规律和影响因素.理论分析和实验结果相一致,对实际生产中产品质量的控制有参考价值.