北京市春夏季大气气溶胶的单颗粒分析表征   总被引：9，自引：0，他引：9  

肖锐刘成德  梁汉东董树屏 F．Adams 《岩矿测试》2004,23(2):125-131

采集了北京市2000年春夏季大气气溶胶样品5个，采用扫描电镜X射线能谱技术分析大气气溶胶单颗粒约2500个。研究结果表明，沙尘期间，矿物尘是最主要的颗粒物种类，非沙尘期间，北京市大气气溶胶中主要检出矿物尘和含硫颗粒物。夏季随着颗粒物污染的加重，含硫颗粒物的数目百分数增加。是北京市大气颗粒物污染的重要特征。重点讨论了Ca-S颗粒、K-S颗粒和Ca-K-S颗粒三类典型含硫颗粒物的化学组成和粒径分布特征。数目可观的Ca-K-S颗粒以及其他硫酸盐颗粒的生成与相对湿度和云量等气象条件相关，这些颗粒物可能是云中过程的产物。减少SO2排放，减少含硫颗粒物，对于控制北京市的大气颗粒物浓度水平具有重要意义。  相似文献   

广东茂名高岭土煅烧实验研究   总被引：1，自引：0，他引：1  

朱粉利  曾伟能  王勤燕  周汉文 《矿产与地质》2004,18(2):168-172

对茂名高岭土进行煅烧，结合X-射线衍射、扫描电子显微镜分析，得到了茂名高岭土在不同温度点煅烧的性能参数，并确定出其非晶化转变的温度是550℃。同时对煅烧过程中的煅烧温度、恒温时间等影响因素进行探讨，结果表明，在茂名高岭土的煅烧过程中，适当延长恒温时间可降低非晶化转变的温度，缩短恒温时间，则非晶化转变温度升高。  相似文献   

四川新康风化淋滤型海泡石的热相变研究   总被引：3，自引：0，他引：3  

王吉中  李胜荣  江永宏 《矿物学报》2004,24(1):55-60

以四川新康风化淋滤型海泡石为研究对象，利用X射线衍射分析和红外光谱分析技术，对海泡石的热相变过程及特征进行了研究。结果发现，四川新康风化淋滤型海泡石的相变过程与沉积型、热液型海泡石相变过程明显不同，其相变过程可以划分为两个阶段：800℃以下保持海泡石相；800℃以上海泡石相转化为斜顽辉石相。  相似文献   

糜棱岩化过程中绿泥石多型与结晶度的演变--以郯庐断裂带南段为例     

王勇生  朱光  刘国生 《矿物学报》2004,24(3):271-277

摘要：根据郯庐断裂带南段韧性剪切带糜棱岩中同构造矿物组合、黑云母的存在以及长石的变形行为，推测其变形．变质温度为400一450oC。bo值分析表明．这些糜棱岩是在低压环境下形成的。在流体作用下。糜棱岩中的绿泥石既可以交代其它矿物而形成，也可以直接从流体中结晶形成。交代其它矿物所形成的绿泥石为Ⅱ型绿泥石，其结晶度值介于0．21^。一0．23^。20．与温度具有较好的对应关系。直接从流体中结晶而产生的绿泥石初始时刻为工型．其结晶度值介于0．236^。-0．341^。20之间，多屑于近变带范畴。其指示温度要低于实际所经历的环境温度。由于糜棱岩化过程中工型绿泥石的不断产生以及工型绿泥石向Ⅱ型绿泥石转化的不充分。导致了在400以上仍然出现工型绿泥石与Ⅱ型绿泥石混合的现象．并且实测的结晶度是不同时刻形成的、具不同结晶度的绿泥石的混合结晶度。  相似文献   

基于EM算法和单幅雷达图像阴影的控制点坡度校正   总被引：1，自引：0，他引：1  

钱俊  舒宁 《武汉大学学报(信息科学版)》2004,29(12):1089-1092

对在我国现有的条件下进行控制点坡度校正的必要性进行了阐述，并分析了EM算法。根据EM算法以及基于区域增长的余弦散射模型建立了控制点坡度校正模型，并用河北省张北地区的雷达影像进行了实验，取得了较高的精度初值。  相似文献   

Seasonal variation of the total electron content, maximum electron density and equivalent slab thickness at a South-American station     

G.A. Mansilla  M. Mosert  R.G. Ezquer   《Journal of Atmospheric and Solar》2005,67(17-18):1687

Total electron content (TEC) and foF2 ionosonde data obtained at Tucumán (26.9°S; 65.4°W) from April 1982 to March 1983 (high solar activity period) are analyzed to show the seasonal variation of TEC, NmF2 (proportional to square of foF2) and the equivalent slab thickness EST. Bimonthly averages of the monthly median for January–February, April–May, July–August and October–November have been considered to represent summer, autumn, winter and spring seasons, respectively. The results show that the higher values of TEC and maximum electron density of F2-layer NmF2 are observed during the equinoxes (semiannual anomaly). During daytime, both in TEC and in NmF2 the seasonal or winter anomaly can be seen. At nighttime, this effect is not observed. Also, the observed NmF2 values are used to check the validity of International Reference Ionosphere (IRI) to predict the seasonal variability of this parameter. In general, it is found that averaged monthly medians (obtained with the IRI model) overestimate averaged monthly median data for some hours of the day and underestimate for the other hours.  相似文献   

The Magnetospheric cusps: A Summary     

T. A. Fritz  Q. G. Zong 《Surveys in Geophysics》2005,26(1-3):409-414

The polar cusps of the magnetosphere are key regions for the transfer of mass, momentum, and energy from the solar wind into the magnetosphere. Understaning these key regions and the dynamical interactions that occur there are fundamentally important to determining the physical nature of the magnetosphere. In this paper we try to summarize many of the conclusions reached in the papers of this special issue emphasizing the present concepts and definition of the cusp, what variations could be temporal structures and what could be spatial structures. We address the need for further measurements and the role of present and planned projects to address these needs.  相似文献   

Sensitivity kernels for finite-frequency surface waves   总被引：1，自引：1，他引：1  

K. Yoshizawa  B. L. N. Kennett 《Geophysical Journal International》2005,162(3):910-926

  相似文献   

Preliminary Characterisation of New Glass Reference Materials (GSA-1G, GSC-1G, GSD-1G and GSE-1G) by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Using 193 nm, 213 nm and 266 nm Wavelengths   总被引：5，自引：1，他引：5  

Marcel Guillong  Kathrin Hametner  Eric Reusser  Stephen A. Wilson  Detlef Günther 《Geostandards and Geoanalytical Research》2005,29(3):315-331

New glass reference materials GSA-1G, GSC-1G, GSD-1G and GSE-1G have been characterised using a prototype solid state laser ablation system capable of producing wavelengths of 193 nm, 213 nm and 266 nm. This system allowed comparison of the effects of different laser wavelengths under nearly identical ablation and ICP operating conditions. The wavelengths 213 nm and 266 nm were also used at higher energy densities to evaluate the influence of energy density on quantitative analysis. In addition, the glass reference materials were analysed using commercially available 266 nm Nd:YAG and 193 nm ArF excimer lasers. Laser ablation analysis was carried out using both single spot and scanning mode ablation. Using laser ablation ICP-MS, concentrations of fifty-eight elements were determined with external calibration to the NIST SRM 610 glass reference material. Instead of applying the more common internal standardisation procedure, the total concentration of all element oxide concentrations was normalised to 100%. Major element concentrations were compared with those determined by electron microprobe. In addition to NIST SRM 610 for external calibration, USGS BCR-2G was used as a more closely matrix-matched reference material in order to compare the effect of matrix-matched and non matrix-matched calibration on quantitative analysis. The results show that the various laser wavelengths and energy densities applied produced similar results, with the exception of scanning mode ablation at 266 nm without matrix-matched calibration where deviations up to 60% from the average were found. However, results acquired using a scanning mode with a matrix-matched calibration agreed with results obtained by spot analysis. The increased abundance of large particles produced when using a scanning ablation mode with NIST SRM 610, is responsible for elemental fractionation effects caused by incomplete vaporisation of large particles in the ICP.  相似文献   

Directional dependence of P- and S-wave propagation and polarization in foliated rocks from the Kola superdeep well: Evidence from laboratory measurements and calculations based on TOF neutron diffraction   总被引：1，自引：0，他引：1  

T.I. Ivankina  H.M. Kern  A.N. Nikitin 《Tectonophysics》2005,407(1-2):25-42

We have measured P- and S-wave velocities on two amphibolite and two gneiss samples from the Kola superdeep borehole as a function of pressure (up to 600 MPa) and temperature (up to 600 °C). The velocity measurements include compressional (Vp) and shear wave velocities (Vs1, Vs2) propagating in three orthogonal directions which were in general not parallel to inherent rock symmetry axes or planes. The measurements are accompanied by 3D-velocities calculations based on lattice preferred orientation (LPO) obtained by TOF (Time Of Flight) neutron diffraction analysis which allows the investigation of bulk volumes up to several cubic centimetres due to the high penetration depth of neutrons. The LPO-based numerical velocity calculations give important information on the different contribution of the various rock-forming minerals to bulk elastic anisotropy and on the relations of seismic anisotropy, shear wave splitting, and shear wave polarization to the structural reference frame (foliation and lineation). Comparison with measured velocities obtained for the three propagation directions that were not in accordance with the structural frame of the rocks (foliation and lineation) demonstrate that for shear waves propagating through anisotropic rocks the vibration directions are as important as the propagation directions. The study demonstrates that proper measurement of shear wave splitting by means of two orthogonal polarized sending and receiving shear wave transducers is only possible when their propagation and polarization directions are parallel and normal to foliation and lineation, respectively.  相似文献