北大别黄土岭麻粒岩锆石U—Pb离子探针定年   总被引：28，自引：6，他引：28  

吴元保  陈道公  夏群科  Etienne DELOULE  程昊 《岩石学报》2002,18(3):378-382

阴极发光显微结构分析表明 ,北大别黄土岭麻粒岩中存在三种类型的锆石 :原岩锆石、麻粒岩相锆石和残留锆石。对它们分别进行离子探针定年 ,得到黄土岭麻粒岩的原岩年龄约为 2 70 0 Ma、麻粒岩相变质事件的年龄为 2 0 5 2± 10 0 Ma、残留锆石的年龄为约 3.4 Ga。以上研究表明黄土岭麻粒岩为残存的扬子板块的结晶基底 ,而约 3.4 Ga残留锆石的发现 ,则首次证明大别山地区存在古太古代的陆壳物质  相似文献   

水准监测网稳定性的观测对分析法     

王孟穹  张献州 《测绘信息与工程》2008,33(6):24-25

选用了第一期单位权方差估值作为整个分析过程参照的标准值,分析了变形监测网稳定性,确定了监测网某期中的动点。  相似文献   

离子色谱法测定地下水中有机氮     

吕凌峰  吴铁夫 《国土资源》1991,(4)

本文探讨了K_2S_2O_8氧化离子色谱法测定有机氮的实验条件,考察了淋洗剂离子价态及淋洗剂总离子强度对低浓度NO_3~-与高浓度SO_4~2-分离的影响;测定了11种含氮有机化台物有机氮的回收率。本法测定地下水中有机氮的结果与经典蒸馏法结果较为一致,具有操作简便、快速、准确,效率高的特点。  相似文献   

NaCl型油田水中I^-的离子选择电极法测定          下载免费PDF全文

陈玉锋杜秀月  冉广芬 《盐湖研究》2007,15(2):30-33

采用了NaCl溶液为离子强度调节剂(TISAB),离子选择电极法测定NaCl型油田水中I-离子的含量,并对该方法进行了测定条件实验的研究。标准曲线在7.94×10-6～1.00 mol/L范围内呈良好的线形关系,相关系数R2=0.999 5,平均回收率为98.9%,RSD(n=6)=1.0%,实验结果表明,该方法测定NaCl型油田水中的I-简便、快速、准确。  相似文献   

A novel high-resolution small ion spectrometer to study ion nucleation of aerosols in ambient indoor and outdoor air     

A.P. Fews  N.K. Holden  P.A. Keitch  D.L. Henshaw 《Atmospheric Research》2005,76(1-4):29

An electrically based ion spectrometer is described, capable of measuring particle sizes and mobilities from molecular ions (small ions) to aerosol particles across a size range of 0.4 to 30 nm in diameter. It consists of a single cylindrical capacitor divided into three electrically insulated sections. The current arriving at the central section is measured by an electrometer and represents the ion flux over a known range of mobilities determined by the applied voltage. The applied voltage is scanned in steps to measure the ion fluxes over a large number of overlapping mobility ranges. The recorded signal and the response function of the instrument are unfolded using a maximum entropy procedure to give a high-resolution measured mobility spectrum. The maximum entropy approach offers a considerable improvement over traditional aspiration collectors and can approach the resolution of a drift tube system. In this way, the spectrometer successfully overcomes the diffusion limit to small ion resolution. Illustrative spectra are shown, demonstrating for the first time the presence of some resolved structure within the small ion spectrum at the highest mobilities. It is demonstrated that the actual mobility spectrum of small ions falls in the range 0.8–2.0 × 10⁻⁴ m² V⁻¹ s⁻¹. This represents a narrower range than that previously measured which is attributed to improved spectral resolution in the present work.  相似文献   

中国雾水化学研究进展   总被引：6，自引：3，他引：3  

李子华  刘端阳  封洋  朱彬  张国正  杨军  濮梅娟 《气象学报》2011,69(3):544-554

1980年以来,中国雾水化学研究发展迅速.在城市、高山和海边广泛地开展了雾的观测试验和云雾水的取样分析,研究了各地云雾水的酸度和酸雾的来源,分析了不同地区雾水化学组分的基本特征.许多雾的综合观测试验,在对雾水连续取样的同时,还连续观测了与雾水化学相关的要素,研究了影响雾水化学组分浓度的主要因子.文中总结了近30年来中国...  相似文献   

Physiological Responses of Halophyte Suaeda salsa to Water Table and Salt Stresses in Coastal Wetland of Yellow River Delta   总被引：3，自引：0，他引：3  

Bo Guan  Junbao Yu  Xuehong Wang  Yuqin Fu  Xingyan Kan  Qianxin Lin  Guangxuan Han  Zhaohua Lu 《洁净——土壤、空气、水》2011,39(12):1029-1035

Soil salinity and waterlogging are two major environmental problems in estuarine wetlands. The objective of this study was to investigate the effects of salt stress, water table, and their combination on growth, chlorophyll content, antioxidant system, and ion accumulation in Suaeda salsa plant, which is the pioneer plant in coastal wetland of the Yellow River Delta (YRD). The results showed that plant height, number of branches, and biomass were significantly affected by water table and salt stress. With enhanced salt stress, the ratio of leaf to total biomass increased and the ratio of root to total biomass decreased. The contents of Chl‐a, ‐b, Chl‐a + b, and carotenoids (Car) decreased significantly with increasing soil salinity and the water table level. Salt stress enhanced the activity of superoxide dismutase (SOD) and catalase (CAT), but reduced the content of protein. With the lowering water table level, the activity of CAT and protein content increased, and activity of SOD decreased. Na⁺ and Cl^? content were up‐regulated with increasing salt stress (NaCl), whereas, the contents of other cations (K⁺, Ca²⁺, and Mg²⁺) and anions ( and ) were decreased. In summary, the results indicated that the S. salsa plants could adapt to the adverse soil environments through modifying their growth and physiology status at the highly saline and intertidal zone, such as the YRD estuarine wetlands, and also could be used as a bio‐reclamation plant to decline the high salt in saline soils.  相似文献   

硫酸盐热化学还原作用对原油裂解成气和碳酸盐岩储层改造的影响及作用机制   总被引：4，自引：3，他引：1  

张水昌  朱光有  何坤 《岩石学报》2011,27(3):809-826

硫酸盐热化学还原作用(Thermochemical sulfate reduction, TSR)是发生在油气藏中复杂的有机-无机相互作用,它不仅会引起含H₂S天然气的富集,其产生的酸性气体对碳酸盐岩储层还具有明显的溶蚀改造作用。本文基于黄金管热模拟实验,研究了TSR反应对原油裂解气的生成的影响,发现这种氧化还原反应的存在能明显降低原油的稳定性,促进具高干燥系数的含H₂S天然气的生成。结合原位激光拉曼实验结果,证实了实际油藏中启动TSR反应的最可行的氧化剂应该是硫酸盐接触离子对(CIP)。全面探讨了影响TSR反应的地质和地球化学因素,提出除了初始原油的组分特征、不稳定含硫化合物(LSC)的含量外,地层水的含盐类型及盐度同样是控制TSR反应的关键因素。同时,基于大量地质分析,发现TSR对碳酸盐岩储层具有明显的溶蚀改造作用。结合溶蚀模拟实验,提出了酸性流体对碳酸盐储层溶蚀改造的机制,且深层碳酸盐岩层存在一个由TSR作用形成的次生孔隙发育带。研究认为,烃类与硫酸盐矿物的氧化还原反应与其产物对碳酸盐岩储层的改造是TSR作用的两个不可分割的部分,它们相互依存和制约。  相似文献   

Impact of post-mixing chemical reactions on the major ion chemistry of bulk meltwaters draining the haut glacier d'arolla,valais, Switzerland     

G. H. Brown  M. J. Sharp  M. Tranter  A. M. Gurnell  P. W. Nienow 《水文研究》1994,8(5):465-480

Until now, alpine glacial meltwaters have been assumed to consist of two components, dilute quickflow and concentrated delayed flow, the mixing of which has been regarded as chemically conservative for the major dissolved ions and electrical conductivity. Dye tracing results suggest that this two-component model adequately represents the sub-glacial hydrology of the Haut Glacier d'Arolla, Switzerland. However, laboratory dissolution experiments in which various concentrations of glacial rock flour are placed in dilute solutions show that this rock flour is highly reactive and suggest that bulk meltwaters may acquire significant amounts of solute through rapid chemical reactions with suspended sediment which occur after mixing of the two components. This view is supported by detailed analysis of variations in the hydrochemistry of meltwaters draining from the Haut Glacier d'Arolla over three diurnal cycles during the 1989 melt season. Variations in the composition of bulk meltwaters are controlled by two main factors: dilution of the delayed flow component by quickflow, and the extent of post-mixing reactions. The latter depends on the suspended sediment concentration in bulk meltwaters and on the duration of contact between these waters and suspended sediment. Seasonal changes in the magnitude of these factors result in changes in the character and causes of diurnal variations in meltwater chemistry. In June, these variations reflect discharge-related variations in residence time within a distributed subglacial drainage system; in July, when a channelized drainage system exists beneath the lower glacier, they primarily reflect the dilution of delayed flow by quickflow; in August, when suspended sediment concentrations are particularly high, they reflect varying degrees of solute acquisition by post-mixing reactions with suspended sediment that take place in arterial channels at the glacier bed.  相似文献   

An improved probabilistic relaxation method for matching multi-scale road networks     

Jianchen Zhang  Wenji Zhao 《International Journal of Digital Earth》2018,11(6):635-655

Matching multi-scale road networks in the same area is the first step in merging two road networks or updating one based upon the other. The quality of the merge or update depends greatly on the matching accuracy of the two road networks. We propose an improved probabilistic relaxation method, considering both local and global optimizations for matching multi-scale of road networks. The aim is to achieve local optimization, as well as to address the identification of the M:N matching pattern by means of inserting virtual nodes to achieve global optimization effects. Then, by adding two attribute-related evaluation indicators, we developed four evaluation indicators to evaluate the matching accuracy, considering both geographic and attribute information. This paper also provides instructions on how to identify the proper buffer threshold during matching procedures. Extensive experiments were conducted to compare the proposed method with the traditional approach. The results indicate that: (1) the overall matching accuracy of each evaluation indicator exceeds 90%; (2) the overall matching accuracy increases by 6–12% after an M:N matching pattern is added, and by 4–6% following the addition of topology indicators; and (3) the proper buffer threshold is about twice the average value of the closest distance from all nodes.  相似文献