大磁暴中环电流离子成分的变化及其与磁暴演化的关系   总被引：3，自引：4，他引：3       下载免费PDF全文

傅绥燕  濮祖荫  宗秋刚  B.Wilken  肖池阶  谢伦 《地球物理学报》2001,44(1):1-11

利用CRRES/MICS的观测数据，研究了磁暴期间内磁层离子成分的变化.对1991年两个典型磁暴和12个大磁暴的分析表明，组成暴时环电流的离子可以分成两组，一组由O⁺、低能H⁺和He⁺组成，起源于电离层(IOP)；另一组为高能H⁺和He⁺⁺，主要来自太阳风(SOP).宁静时环电流主要成分为SOP，大磁暴主相极大时环电流的主要成分是IOP.大磁暴期间离子可被注入到很低的高度(L=3-4).IOP对环电流的贡献随磁暴强度增大而增加，在大磁暴主相极大时可达80%(数密度).IOP中O⁺的快速增减是导致Dst指数在磁暴主相期间快速下降和恢复相中快速增长的主要原因.小磁暴中(D_st＞-50nT)O⁺对环电流的贡献可以忽略不计.  相似文献   

雪冰中生物有机酸的测试分析方法研究   总被引：4，自引：2，他引：4  

李心清  秦大河  周会 《冰川冻土》2001,23(1):85-91

生物有机酸是构成酸雨的组分类别，对地表环境有着重要影响，由于其来源与生物界关系密切，因此，对其在雪冰中记录的研究是从历史的角度认识C，H，O等生源元素生物地球化学循环，认识过去生态和环境变化的途径之一，但是，由于其含量较低，易遭受污染等原因，雪冰中有机酸含量的定量测定一直是困扰研究人员的一个问题，在对目前有机酸测试分析现状，测试分析的难点和问题调研的基础上，文章提出了一种利用DX－300离子色谱测试山地冰川雪冰中生物有机酸含量的方法，该方法利用AS4A分析柱，AG4A保护柱，TAC－2样品富集柱和ATC－1阴离子捕集柱，以梯度淋洗方式，在14min内可分离检测出甲酸，乙酸，丙酮酸，甲烷磺酸，草酸等有机酸根离子及氟，氯，亚硝酸，硝酸，溴，磷酸和硫酸等常见无机阴离子，上述有机，无机离子的测试分析相对标准误差分别为：氟（2．0％），乙酸（4．5％），甲酸（2．0％），甲烷磺酸（16．9％），氯（3．1％），亚硝酸（3．9％），硝酸（2．2％），溴（4．9％）和硫酸（2．4％）。  相似文献   

Theoretical and experimental study of time domain-induced polarization in water-saturated sands   总被引：1，自引：0，他引：1  

K. Titov  V. Komarov  V. Tarasov  A. Levitski 《Journal of Applied Geophysics》2002,50(4)

A theoretical model of spectral-induced polarization (IP) of sand is presented. In the proposed model, contacts of sand grains and intergrain solution-filled space are considered as electrical current passages of varying thickness, which differ in values of ion transport number. Ion-selective narrow passages are considered as active zones, large passages as passive. The proposed model describes spectral IP characteristics for the medium where the length of passive zones is much greater than the length of active ones. The model is called short narrow pores (SNP) model. The SNP model predicts a growth of IP time constant with increase of length of ion-selective zone. Both the time domain and frequency domain parameters are described. The parameters of Cole–Cole model corresponding to the SNP model were also found.The behaviour of model parameters is compared with experimental data obtained on natural and sieved sands using time domain technique. The natural sand spectra correspond neither to the simple SNP model nor simple Cole–Cole model with single time constant because the lengths of ion-selective zones vary, reflecting the grain-size distribution.The spectra of sieved sand compared with the theoretical SNP spectra reveal close correspondence between experimental data and theoretical parameters. For four sieved sands, both the theoretical and experimental data show that the time constant of the IP is proportional to the square of the average grain size.  相似文献   

应用表面活性剂的协合效果研制高效润滑剂   总被引：1，自引：0，他引：1  

黄振国 《铀矿地质》1992,8(2):118-122

  相似文献   

Pore water evolution in oilfield sandstones: constraints from oxygen isotope microanalyses of quartz cement     

Ann M.E Marchand  Calum I MacaulayR.Stuart Haszeldine  Anthony E Fallick 《Chemical Geology》2002,191(4):285-304

Oxygen isotope microanalyses of authigenic quartz, in combination with temperatures of quartz precipitation constrained by fluid inclusion microthermometry and burial history modelling, are employed to trace the origin and evolution of pore waters in three distinct reservoirs of the Brae Formation in the Miller and Kingfisher Fields (North Sea). Oxygen isotope ratios of quartz cements were measured in situ in nine sandstone thin sections with a Cameca ims-4f ion microprobe. In conjunction with quartz cement paragenesis in the reservoirs, constrained from textural and cathodoluminescence (CL) microscopy studies, pore water evolution was reconstructed from the time of deposition of the sandstones in the Upper Jurassic until the present.CL photomicrographs of quartz overgrowths in the Brae Formation sandstones show three cement zones (A, B and C) which can be related to different oxygen isotope compositions: (1) the earliest, and thinnest, zone A (homogeneous CL pattern with probable δ¹⁸O values between +23‰ and +26‰—direct measurements were not possible) precipitated in the sandstones at temperatures <60 °C; (2) the second zone B (complex CL pattern and directly measured δ¹⁸O values between +15‰ and +18‰) precipitated in the sandstones most likely between 70 and 90 °C; (3) the third zone C (homogeneous CL pattern and directly measured δ¹⁸O values between +16‰ and +22‰) precipitated in the sandstones most likely at temperatures >90 °C. Calculated oxygen isotope compositions of pore waters show that zone A quartz cements, and enclosing concretionary calcite, precipitated from a meteoric-type fluid (∼−7‰) during shallow burial (<1.5 km). Zone B quartz cements precipitated from fluids which evolved in composition from a meteoric-type fluid (δ¹⁸O −7‰) to a more ¹⁸O-enriched fluid (δ¹⁸O −4‰) as burial continued to ∼3.0 km. Data from zone C quartz cements are consistent with further fluid evolution from δ¹⁸O −4‰ to basinal-type fluids with δ¹⁸O similar to the present-day formation water oxygen isotope composition (+0.6‰ at 4.0 km burial). A similar pore water evolution can be derived for all three reservoirs studied, indicating that hydrogeologic evolution was similar across sandstones of the whole Brae Formation.The quartz cement zones observed in the Brae Formation sandstones, and the pore water history derived for the area studied, is analogous to published petrographic and pore water evolution data from the nearby Brent Group reservoirs and from reservoirs located in the Haltenbanken area on the Atlantic margin offshore Norway. Considering quartz cement is a major porosity-occluding phase in many reservoir sandstones, and because pore waters both dissolve quartz and carry the dissolved silica to cementation sites, the data presented are valuable for improving the understanding and prediction of reservoir quality development in sandstones globally.  相似文献   

利用Leberl模型进行机载SAR图像的立体定位     

高力赵杰  王仁礼 《测绘学院学报》2004,21(4):269-271

随着微波遥感技术逐步走向实用化，雷达摄影测量技术研究也越来越受到重视。从SAR图像的成像特点出发，研究了Leberl雷达构像模型的描述和解算过程．实现雷达影像立体定位的理论和方法。并通过实验加以证实。  相似文献   

青藏高原东北部强震成组孕震特征初探     

马文静  苏旭 《高原地震》1997,(3)

通过对1986年门源6．4级地震以来青藏高原东北部发生的一系列6级强震时空分布特征的研究，提出了这些地震为成组孕震的观点，并从背景空区、诱发地震、地震活动增强及前兆异常的突变等方面论证了成组孕震的可能性。  相似文献   

以草酸钠为原料膜法制取草酸和烧碱的研究          下载免费PDF全文

郑竹林 《盐湖研究》1997,5(2):36-50

本文提供了一个用离子膜电解法生产草酸的新工艺，研究了草酸钠的提纯和制取草酸新方法的工艺条件，求取了技术经济指标，解决了传统工艺的三废污染和产品质低等问题。  相似文献   

水溶液体系的化学平衡模型   总被引：10，自引：0，他引：10  

李军  高世扬 《地球科学进展》1994,9(5):32-38

概括了化学平衡计算的历史及特点；对在地球化学研究中常用的水溶液体系化学平衡模型作了简要的介绍；讨论了水溶液体系化学平衡模型研究的现状及今后的发展动向。  相似文献   

IP-1型离子泵测氦仪及其在放射性水化找矿中的初步试验     

谢文彦  王建谱  冯倡  张振祥  吴平庆  季春峰 《铀矿地质》1985,(1)

讨论了IP—1型离子泵测氦仪的工作原理及基本技术特性。通过野外工作,证明仪器具有性能比较稳定、灵敏度较高,便于携带等特点。介绍了仪器在已知铀矿床上开展放射性水化学找矿的试验结果。测量资料表明,在有利的地质、水文地质条件下,水氦异常能较好的指明深部铀矿化范围。  相似文献