A Laboratory and Theoretical Study on the Uptake of SO2 Gas by Large and Small Water Drops Containing Heavy Metal Ions     

A. Heusel-Waltrop  K. Diehl  S. K. Mitra  H. R. Pruppacher 《Journal of Atmospheric Chemistry》2003,44(2):211-223

Laboratory experiments have been carried out to investigate the uptake of sulfur dioxide by water drops containing heavy metal ions where the metal ions serve as catalysts to oxidise the taken up S(IV) into S(VI). During the gas uptake the drops were freely suspended at their terminal velocity in the airstream of the Mainz vertical wind tunnel. Two series of experiments were carried out, one with large millimeter size water drops containing manganese or iron ions, and the other with small water drops containing manganese ions and having radii in hundreds of micron size range. The experimental results were compared against model computations using the Kronig–Brink model and the fully mixed model, modified for the case that heavy metal ions present in the liquid phase act as catalysts for the oxidising process. The results of the model calculations show that there are only small differences between the predicted gas uptake according to the two models. In addition it was found that the experimental obtained results from the uptake of SO₂ by water drops containing heavy metal ions for both, large and small water drops did agree with the model results.  相似文献   

闪电首次回击过程的光谱特性   总被引：3，自引：5，他引：3  

袁萍  刘欣生  张义军  张翠华  郄秀书 《高原气象》2003,22(3):235-238,T006

用无狭缝摄谱仪，拍摄了4次云对地闪电首次回击过程390一660nm波长范围的光谱，并将原子结构的理论应用于闪电光谱的研究，用多组态Dirac—Fock方法，系统考虑相对论效应、电子关联、弛豫效应等重要贡献，对光谱的精细结构进行了计算，给出了谱线的波长、振子强度以及相应的上能级激发能量。通过与试验观测谱线的比较分析发现，大多数谱线对应的上激发能在23ev左右。首次回击过程中，闪电通道内NII离子的密度最大，并且大多数处于n＝3的激发态。  相似文献   

唐古拉山冬克玛底冰川雪层中淋溶作用的初步研究   总被引：7，自引：7，他引：7  

侯书贵  秦大河 《冰川冻土》1996,18(3):227-234

利用唐古拉山冬克玛底冰川雪坑和表层积雪样品的实测资料，初步探讨本区雪层中离子淋溶作用的特征，影响因素及其对冰芯记录的干扰。研究发现淋溶作用能够对数周至数月时间尺度的雪层记录产生“平滑”作用，但不会影响冰芯记录的长期变化趋势。  相似文献   

湘南稀土矿床的放射性特征及其对开采的影响     

谭光贵 《湖南地质》1996,15(4):229-233

湘南主要稀土矿区的岩、矿石和稀土矿物的放射性特征表明，矿区放射性强度的高低与稀土总量无关，而与矿石的铀、钍含量密切相关；主要矿区的放射性对其开发与产品都没有影响，但长期接触对人体有一定危害。因此，开采时必须加强防护，防止放射性的长期照射，并选用无放射性的清洁饮用水，以保护人体健康。  相似文献   

Impact of UV-B, Heat and Chemicals on Ethylene-Production of Lichens     

Jacob Garty  Lior Weissman  Tal Levin  Rachel Garty-Spitz  Haya Lehr 《Journal of Atmospheric Chemistry》2004,49(1-3):251-266

To assess the impact of UV-B radiation combined with NaHSO₃ in solution under laboratory conditions, we compared the amounts of stress-ethylene produced by two lichen species of the same genus. Ramalina lacera, an epiphytic Mediterranean lichen, was found to be rather sensitive to UV-B combined with NaHSO₃, relative to the epilithic desert lichen R. maciformis. The impact of high temperatures with FeCl₂ in solution, measured by amounts of stress ethylene accentuated the adaptability of R. maciformis to desert conditions, whereas R. lacera appeared to be rather sensitive to extreme temperatures especially in the case of chemical contamination. The adaptability of R. maciformis to UV-B appears to be related to the photoprotective capabilities of lichen substances.  相似文献   

Spatial and Temporal Cusp Structures Observed by Multiple Spacecraft and Ground Based Observations     

K. J. Trattner  S. A. Fuselier  T. K. Yeoman  C. Carlson  W. K. Peterson  A. Korth  H. Reme  J. A. Sauvaud  N. Dubouloz 《Surveys in Geophysics》2005,26(1-3):281-305

Downward precipitating ions in the cusp regularly exhibit sudden changes in ion energy distributions, forming distinctive structures that can be used to study the temporal/spatial nature of reconnection at the magnetopause. When observed simultaneously with the Polar, FAST, and Interball satellites, such cusp structures revealed remarkably similar features. These similar features could be observed for up to several hours during stable solar wind conditions. Their similarities led to the conclusion that large-scale cusp structures are spatial structures related to global ionospheric convection patterns created by magnetic merging and not the result of temporal variations in reconnection parameters. The launch of the Cluster fleet allows cusp structures to be studied in great detail and during changing solar wind conditions using three spacecraft with identical plasma and field instrumentation. In addition, Cluster cusp measurements are linked with ionospheric convection cells by combining the satellite observations with SuperDARN radar observations that are used to derive the convection patterns in the ionosphere. The combination of satellite observations with ground-based observations during variable solar wind conditions shows that large-scale cusp structures can be either spatial or temporal. Cusp structures can be described as spatial features observed by satellites crossing into spatially separated flux tubes. Cusp structures can also be observed as poleward-traveling (temporal) features within the same convection cell, most probably caused by variations in the reconnection rate at the magnetopause.  相似文献   

Ressi experimental catchment: Ecohydrological research in the Italian pre-Alps     

Giulia Zuecco  Chiara Marchina  Ylenia Gelmini  Anam Amin  H. J. van Meerveld  Daniele Penna  Marco Borga 《水文研究》2021,35(3):e14095

Ressi is a small (2.4 ha) forested catchment located in the Italian pre-Alps. The site became an experimental catchment to investigate the water fluxes in the soil–plant–atmosphere continuum and the impact of vegetation on runoff generation in 2012. The elevation of the catchment ranges from 598 to 721 m a.s.l. and the climate is humid temperate. The bedrock consists of rhyolites and dacites; the soil is a Cambisol. The catchment is covered by a dense forest, dominated by beech, chestnut, maple, and hazel trees. The field set up includes measurements of the rainfall in an open area, streamflow at the outlet, soil moisture at various depths and locations, and depth to water table in six piezometers at a 5- or 10-min interval. Samples of precipitation, stream water, shallow groundwater and soil water are collected monthly for tracer analysis (stable isotopes (²H and ¹⁸O), electrical conductivity and major ions), and during selected rainfall–runoff events to determine the contribution of the various sources to runoff. Since 2017, soil and plant water samples have been collected to determine the sources of tree transpiration. Data collected in the period 2012–2016 are publicly available. Data collection is ongoing, and the data set is expected to be updated on an annual basis to include the most recent measurements.  相似文献   

Diel stream geochemistry,Taylor Valley,Antarctica     

Sarah K. Fortner  W. Berry Lyons  LeeAnn Munk 《水文研究》2013,27(3):394-404

Unlike temperate and polythermal proglacial streams, the proglacial streams in Taylor Valley (TV), Antarctica, are derived primarily from glacier surface melt with no subglacial or groundwater additions. Solute responses to flow reflect only the interaction of glacial meltwater with the valley floor surrounding the stream channel. We have investigated the major, minor and trace element 24‐h variations of two proglacial melt streams, Andersen Creek and Canada Stream, originating from the Canada Glacier in TV, Antarctica. Both streams exhibited diel mid‐austral summer diurnal flow variation, with maximum flow being more than 50 times the minimum flow. Dissolved (< 0.4 µm) major, minor and trace solute behaviors through diel periods were strongly controlled by the availability of readily solubilized material on the valley floor and hyporheic‐biological exchanges. Anderson Creek had generally greater solute concentrations than Canada Stream because of its greater receipt of eolian sediment. Andersen Creek also acquired greater solute concentrations in the rising limb of the hydrograph than the falling limb because of dissolution of eolian material at the surface of the stream channel coupled with minimal hyporheic‐biological exchange. Conversely, Canada Stream had less available eolian sediment, but a greater hyporheic‐biological exchange, which preferentially removed trace and major solutes in the rising limb and released them in the falling limb. Given the dynamic nature of discharge, eolian, and hyporheic‐biological processes, solute loads in TV streams are difficult to predict. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

固定化海藻吸附金属离子的影响因素   总被引：7，自引：0，他引：7  

王宪  邱海源  钱爱红  陈丽丹  郑盛华 《海洋学报》2006,28(1):62-66

研究了固定化海带吸附含铜、镉溶液过程的影响因素,结果表明,在pH为3.0~5.0时对Cu2+保持高的吸附率,在pH为4.0时对Cd2+的吸附率达到最大.随着Cu2+,Cd2+金属离子初始浓度的降低,吸附率有所降低.对Cd2+的吸附率均随着温度的升高而变大.随着吸附剂浓度的增大,对Cu2+,Cd2+的吸附率逐渐升高,与此相反,对Cu2+,Cd2+的吸附量则逐渐减小.粒径对Cu2+的吸附率影响较小,对Cd2+的吸附率有较明显的变化.  相似文献   

DFT对Rb⁺水合团簇及其相关性质的分析          下载免费PDF全文

张文倩  葛蒲  房春晖  周永全  朱发岩  刘红艳  李武 《盐湖研究》2019,27(3):81-92

运用密度泛函理论(DFT)在ωB97XD/gen (O、H元素Aug-cc-PVDZ; Rb元素Lanl2DZ)基组水平上研究了[Rb(H_2O)_n]~+(n=1～12)水合团簇的结构和光谱学性质。研究结果表明,通过分析气相和液相中的稳定能以及水合团簇可知,稳定构型出现在8配位的团簇中。第一配位层水分子数为8时形成Rb~+第一近似饱和水合层。此外,拉曼光谱显示[Rb(H_2O)_n]~+(n=1～12)水合团簇中O-H伸缩振动峰随着水分子数增加发生移动和加宽,Rb~+发生水合时,O-H对称和非对称伸缩振动发生红移,随着水合数的增多,频率蓝移。此外,文中对拉曼光谱中O-H振动的频率位置结合团簇结构进行了说明。  相似文献