南京冬季辐射雾和平流辐射雾的化学特征差异   总被引：1，自引：0，他引：1  

杨军  谢玉静  石春娥  刘端阳  牛生杰  李子华 《南京气象学院学报》2009,32(6):776-782

利用2006和2007年冬季南京雾外场试验中取得的雾水离子成分资料,分析了雾水化学组分特征,探讨了雾水酸度来源及辐射雾和平流辐射雾的化学特征差异。结果表明,南京冬季雾水中总离子浓度偏高,浓度最高的3种离子成份是SO^-24、NH^＋4和Ca^2＋,但雾水酸性不强,碱性离子成分的中和作用是pH值较高的原因。平流辐射雾中雾水离子总浓度约为辐射雾的2.2倍,平流辐射雾中浓度最高的阳离子为NH^＋4,辐射雾中为Ca^2＋。  相似文献   

Hydrogen Isotopic Compositions of Pyroxenes in Nushan Peridotite Xenoliths,SE China     

YU Huimin  XIA Qunke  E.DELOULE  YANG Xiaozhi CAS Key Laboratory of Crust-Mantle Materials  Environments  School of Earth  Space Sciences  University of Science  Technology of Chin  Hefei  Anhui  Chin  CRPG-CNRS  BP  Vandoeuvre Cedex  France 《《地质学报》英文版》2005,79(3):336-342

Hydrogen isotopic compositions of pyroxenes in peridotite xenohths from the Nushan volcano, Anhui Province, SE China have been obtained using an ion probe (Cameca 1270). D/H ratios are constant within a single grain and among the different grains from the same sample. The lack of correlation between the D/H ratios and the hydrogen contents indicates that the hydrogen isotopic compositions are inherited from their mantle source. Combining with the δD values of coexisting amphiboles, it is inferred that the Nushan mantle experienced at least a two-stage metasomatic event.One was responsible for formation of amphiboles with extremely variable δD values, and the other was probably responsible for the high δD values (up to -20‰) of some clinopyroxenes from peridotites, clinopyroxene and mica megacrysts. High δD values point to a subduction-related fluid being involved in one metasomatic event. The primary δD values (-90‰ to -140‰) of the Nushan pyroxenes, together with data gleaned from the literature, suggest that the D/H ratios of the nominally anhydrous mineral reservoir might have differed from that of the other mantle hydrogen in being relatively depleted in D.  相似文献   

天然石墨--形成的实验证据和特殊应用   总被引：1，自引：0，他引：1  

MichioINAGAKI 《地学前缘》2005,12(1):171-181

简要讨论了碳前驱物的石墨化现象,总结了当有或无其他矿物共存环境下碳材料在承压条件下发生石墨化的实验结果。以这些实验研究成果为基础,讨论了自然界石墨生成的机理。此外,对天然石墨的某些特殊应用作了综述,如用作可再充电锂离子电池的阳极材料,特别是片状石墨用作泄漏重油的吸附材料等。  相似文献   

Deep drainage sensitivity to climate,edaphic factors,and woody encroachment,Oklahoma, USA          下载免费PDF全文

Michael L. Wine  Jan M. H. Hendrickx  Daniel Cadol  Chris B. Zou  Tyson E. Ochsner 《水文研究》2015,29(17):3779-3789

Because groundwater is Earth's largest pool of freshwater, understanding the sensitivity of deep drainage to climate, soils, and land cover is critical in managing water resources. To better understand controls on this critical flux in the context of woody encroachment, we determined the sensitivity of deep drainage to climate, soil texture, soil compaction, rooting depth, growing season duration, and plant–water stress response using Hydrus‐1D to simulate deep drainage. To evaluate the simulation results, we compared these results with ground measurements at two anchor sites. At both anchor sites, Hydrus‐1D predictions of deep drainage matched measured values within the errors inherent in ground measurements. Sensitivity analysis suggested greatest sensitivity of deep drainage to climate (24 mm yr^?1) and rooting depth (12 mm yr^?1), moderate sensitivity to growing season duration (5 mm yr^?1) and soil texture (4 mm yr^?1), and lowest sensitivity to topsoil compaction and plant–water stress response (3 mm yr^?1). The sensitivity analysis indicated the relative importance of the plant‐related factors considered, which, in decreasing order, were rooting depth, growing season duration, and plant–water stress response – factors that change concomitantly as a result of forestation or woody encroachment. Further ground‐truth measurements of woody encroachment effects on deep drainage are needed to confirm or refine the results of this simulation modelling study. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

A tracer‐based simulation approach to quantify seasonal dynamics of surface‐groundwater interactions in the Pantanal wetland          下载免费PDF全文

J. Schwerdtfeger  A. Hartmann  M. Weiler 《水文研究》2016,30(15):2590-2602

The Pantanal wetland is one of the least explored regions of South America. It is characterized by an outstanding flora and fauna adapted to a seasonal flood pulse controlled by a dry and a wet season within each year. The resulting inundation covers in average an area of approximately 150 000 km² and is seen as the most important driver for ecological integrity. Evaporation from the large floodplain is supposed to influence the climate of the whole continent. The regional groundwater is connected to the surface water and plays an important role for the characteristic flooding regime by regulating the wetland's water table. The water balance assessment of the wetland and the internal water exchange between surface and groundwater is therefore of high relevance for the conservation of the Pantanal biodiversity. Despite of its importance, water balance studies including groundwater–surface water interactions based on field data are rarely undertaken. This is mainly due to the remoteness and difficulty in accessing this area, which results in lack of data. In our study, we developed a new tracer‐based model to simulate the spatio–temporal surface and subsurface fluxes for a range of water bodies. The model was able to simulate these fluxes considering a dynamic simulation of inflow and outflow using a newly collected 2‐year dataset of water levels, stable water isotopes and chloride collected from several water bodies in the northern Pantanal region. Quantitative differences between water bodies according to their location in the floodplain were determined by the flooding regime and connectivity as well as site‐specific characteristics, such as hydraulic conductivity and water depth. Our model simulated water balance fluxes with a Nash–Sutcliffe efficiency of 0.61, whereas it simulated stable water isotopic compositions better than chloride. We present the first study based on field data for the Pantanal, which is able to quantify water balances fluxes. Because their representation in global climate and land cover products is insufficient, our simulation results are valuable for validating large‐scale models. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

夏季玉龙雪山及丽江盆地水体主要无机离子特征     

朱国锋  何元庆  蒲焘  王淑新  辛惠娟  王春凤 《地理科学进展》2011,30(7):868-874

为探究玉龙雪山地区地-气-水-人之间的相互作用机理,于2005年7月22-28日在云南省丽江市玉龙雪山地区采集不同水体样品,在探讨不同水体水文联系的基础上,对该区域不同水体的无机离子浓度和特征进行了分析。结果表明玉龙雪山地区不同水体无机离子浓度存在较为明显的差距,无机离子浓度较大的是低海拔地区的湖水和地下水,浓度较小的是冰舌融水和融水径流;水体主要无机离子是HCO3-,Ca2＋,Mg2＋,SO42-,Na＋,K＋,Cl-,其中Ca2＋占整个阳离子的53.27%,是最大优势阳离子,阴离子中HCO3-是优势阴离子,占阴离子总量的70.35%左右,优势离子与非优势离子之间浓度差距较大。海拔4270 m以上,受局地岩石岩性的影响无机离子浓度较高;海拔42703180 m,由于新鲜融水未充分溶解基岩的离子和水体本身的沉积作用,离子浓度较低;海拔30462400 m,水岩作用导致水体HCO3-,Mg2＋,Ca2＋,K＋,Na＋浓度较高,季风输送和近源人类活动导致NO3-、SO42-,K＋浓度也较高;相关性分析表明阳离子的来源、存在方式和反应机理的相似性比阴离子强;SO42-对区域水岩反应有较强的加速作用;Mg2＋和Ca2＋同源。  相似文献   

Selective Separation/Preconcentration of Silver Ion in Water by Multiwalled Carbon Nanotubes Microcolumn as a Sorbent     

Pourya Biparva  Mohammad Reza Hadjmohammadi 《洁净——土壤、空气、水》2011,39(12):1081-1086

The present paper proposes the application of multiwalled carbon nanotubes (MWCNTs) as a solid adsorbent for selective separation/preconcentration of silver(I) in water samples prior to flame atomic absorption spectrometry. The procedure is based on the solid phase extraction of Ag(I)–2‐mercaptobenzothiazole chelate on MWCNTs. The elution step is carried out with 5 mL of 2 mol L^?1 HNO₃ in acetone solution at a flow rate of 1.0 mL min^?1. The influences of the various analytical parameters including pH of the solution, eluent type, sample volume, flow rates of eluent, matrix ions were investigated for optimization of the presented procedure. Tests of addition/recovery for analyte ion in real samples were performed with satisfactory results. Preconcentration factor and limit of detection for Ag(I) were 160 and 0.21 µg L^?1, respectively. The synthesized MWCNT exhibited excellent stability in eluent solution and its adsorption capacity was 5.4 mg of silver per gram of sorbent. The proposed method was successfully applied to trace silver determination in a variety of environmental water samples.  相似文献   

简单体系水溶液包裹体pH和Eh的计算   总被引：2，自引：0，他引：2  

刘斌 《岩石学报》2011,27(5):1533-1542

流体包裹体pH和Eh参数的计算一直处于探索阶段。已经发表的计算公式,由于缺少高压(＞1bar)环境下化学组分反应平衡常数,常常利用常压(1大气压)下化学组分反应平衡常数代替而推导出的,对于大多数自然界捕获的包裹体,不可避免地产生较大计算误差。根据水溶液包裹体中离子反应热力学特征,结合前人推导的计算公式,我们分别建立简单体系水溶液包裹体pH和Eh计算公式。由于利用较高压(＞1bar)化学反应平衡常数,基本上解决不同条件下、特别在较高温度、压力下捕获的水溶液包裹体pH和Eh的计算难题。4种简单体系水溶液包裹体pH计算公式:① H₂O包裹体:pH=pK_w② CO₂-H₂O包裹体: ³－(m_CO2K_a,1+K_W)· －2mCO₂K_a,1K_a,2=0③ NaCl-H₂O包裹体: ²= ④ CO₂-H₂O-NaCl包裹体: ³+ ²－(m_CO2·K_a,1+K_w)· －2mCO₂·K_a,1·K_a,2－ =0计算数值精度分析表明:CO₂-H₂O和NaCl-H₂O包裹体的pH值按照公式计算,相同或接近于实际测定的天然酸雨、海水pH数值范围。CO₂-H₂O-NaCl包裹体与Crerar(1978)公式计算误差不超过10%。4种简单体系水溶液包裹体Eh的计算,引用Ryzhenko and Bryzgalin (1984)年推导的Eh公式。文中列举了3个实例,详细叙述不同类型包裹体捕获温度、压力下pH和Eh计算过程。自然界中水溶液包裹体成分十分复杂,本文涉及的只是自然界几种简单体系水溶液包裹体,给出的pH和Eh公式只对特定组分组合反应平衡条件有效,它不适合另外一种组分组合平衡条件下的关系,因此使用时务必注意平衡的组分组合条件。  相似文献