1999年北京持续高温天气过程的诊断分析     

吴振鹏  武媛  李乃杰 《气象与环境科学》2016,39(1):82-88

利用北京观象台观测资料和NCEP/NCAR再分析数据,对1999年6月24日至7月2日北京一次持续性高温天气的演变和发展过程及非绝热加热作用对系统的影响进行诊断分析,结果表明：在此次高温天气发生前,欧亚大陆中高纬度环流经向度很大,欧洲北部和贝加尔湖以南为高压脊控制,中亚和我国东北地区则处于低压槽内。贝加尔湖南部的高压脊纬向延伸范围较广,在东移过程中长时间影响北京。随着贝加尔湖以南的高压脊逐渐东移,北京上空下沉增温与非绝热加热作用有所增强,北京逐渐受到高温天气影响。在高温天气发生的后半阶段,我国东北的低压槽入海后在120130°E附近维持并发展,槽前非绝热加热率很大。从垂直方向来看,加热率在500 hPa以下随高度迅速增加,根据全型涡度方程,强烈的非绝热加热率垂直分布不均作为一个明显的涡度源区,对入海低压槽的稳定维持有显著的作用。而入海低压槽的稳定维持,又阻碍了华北高压脊的东移,使其在北京地区长时间稳定少动,为北京带来多日的持续性高温天气。  相似文献   

Evidence of technetium and iodine release from a sodalite-bearing ceramic waste form     

《Applied Geochemistry》2016

Sodalites have been proposed as a possible host of certain radioactive species, specifically ⁹⁹Tc and ¹²⁹I, which may be encapsulated into the cage structure of the mineral. To demonstrate the ability of this framework silicate mineral to encapsulate and immobilize ⁹⁹Tc and ¹²⁹I, single-pass flow-through (SPFT) tests were conducted on a sodalite-bearing multi-phase ceramic waste form produced through a steam reforming process. Two samples made using a steam reformer samples were produced using non-radioactive I and Re (as a surrogate for Tc), while a third sample was produced using actual radioactive tank waste containing Tc and added Re. One of the non-radioactive samples was produced with an engineering-scale steam reformer while the other non-radioactive sample and the radioactive sample were produced using a bench-scale steam reformer. For all three steam reformer products, the similar steady-state dilute-solution release rates for Re, I, and Tc at pH (25 °C) = 9 and 40 °C were measured. However, it was found that the Re, I, and Tc releases were equal or up to 4.5x higher compared to the release rates of the network-forming elements, Na, Al, and Si. The similar releases of Re and Tc in the SPFT test, and the similar time-dependent shapes of the release curves for samples containing I, suggest that Re, Tc, and I partition to the sodalite minerals during the steam reforming process.  相似文献   

中国铝土岩系中伴生钪资源富集规律及富集机制初探     

刘国栋  付勇  何伟  唐波  龙珍  杨颖  龙克树 《地质论评》2021,67(3):67040003-67040003

钪(Sc)作为新世纪的重要资源,广泛分布于自然界中,但其分布极为稀散,钪的独立矿物稀少,独立矿床几乎没有。铝土岩系中的钪资源储量巨大,本文统计了中国各铝土矿成矿带Sc数据,在对比山西(断隆)成铝区、华北陆块南缘成铝区、渝南—黔北成铝带、黔中成铝区和滇东南—桂西成铝区的数据基础上,发现滇东南—桂西成铝区的Sc含量最高,含钪铝土岩系形成时代主要为石炭纪和二叠纪。通过对比分析A/S与钪的关系,在A/S小于2.5,钪的含量总体较高,且与A/S正相关,大于2.5后,与A/S负相关。从而得出在铝土岩系中,Sc分布在顶层的黏土岩、中部的铁质铝土矿以及底部的铁质黏土岩、铁质岩,尤其是在含铁铝土岩系中高度富集。通过对比分析铝土岩系各元素含量,发现钪与铁、铌、钒、铬元素成正相关,综合铝土岩系中其他元素的矿物表现形式,推测钪在铝土岩系中的赋存形式可能为：类质同象、离子吸附、和超显微非结构混入物。本文初步探讨总结钪在铝土岩系中可能的赋存形式、时空分布规律及钪的迁移转化机制,为铝土矿中伴生钪资源的综合利用开发提供理论支撑。  相似文献   

松嫩平原吕大火房垂直剖面中硒赋存形态及影响因素分析     

张立  姜侠  崔玉军  窦智慧  李瑛  孙振伟 《地质与资源》2021,29(6):603

  相似文献   

Elastic fields in two joined transversely isotropic media of infinite extent as a result of rectangular loading     

H. T. Xiao  Z. Q. Yue 《国际地质力学数值与分析法杂志》2013,37(3):247-277

This paper presents the closed‐form solutions for the elastic fields in two bonded rocks induced by rectangular loadings. Each of the two bonded rocks behaves as a transversely isotropic linear elastic solid of semi‐infinite extent. They are completely bonded together at a horizontal surface. The rectangular loadings are body forces along either vertical or horizontal directions and are uniformly applied on a rectangular area. The rectangular area is embedded in the two bonded rocks and is parallel to the horizontal interface. The classical integral transforms are used in the solution formulation, and the elastic solutions are expressed in the forms of elementary harmonic functions for the rectangular loadings. The stresses and displacements in the rocks induced by both the horizontal and vertical body forces are also presented. The numerical results illustrate the important effect of the anisotropic bimaterial properties on the stress and displacement fields. The solutions can be easily implemented for numerical calculations and applied to problems encountered in rock mechanics and engineering. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

自然金粒级形态模拟     

李怀谦 《铀矿地质》1988,(4)

粒级、形态含量分布模拟的基本原理就是首先按对数正态分布产生出自然金的短边和长边,再将二者的乘积分别按短边和二者的比值进行统计归类。用计算机对自然金的粒级形态进行模拟可显著提高粒级、形态计算的精确度,使之更符合客观情况,同时也可节省工时。  相似文献   

锡石的晶体结构和形态的关系          下载免费PDF全文

柴钢  王文魁 《岩石矿物学杂志》1988,7(4):374-381

本文对不同成因类型的锡石晶体形态进行了研究,并从PBC(周期性键链)理论出发,讨论了锡石晶体形态与晶体结构的关系。笔者认为,锡石晶体具有三种F面,即s{111}、e{101}、m{110},与Hartman对同样结构类型的金红石晶面性质划分有所差异。据锡石晶面结构性质所推导的理想晶体形态图,与晶体测量所得到的天然晶体形态图总体上相吻合。  相似文献   

测老庙盆地水中铀的存在形式及其找矿意义     

谭鸿赞 《铀矿地质》1990,6(3):145-151

本文通过热力学的计算方法,确定了测老庙盆地水中铀的存在形式,分析了铀在水中的迁移规律和沉淀条件。并应用饱和指数的找矿机理,对测老庙盆地的找矿前景提出了水文地球化学依据。  相似文献   

新疆萨尔布拉克金矿找矿矿物学标型特征研究   总被引：2，自引：1，他引：2  

吕瑞英 《地球科学》1990,15(6):657-665

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比值R分析及其在宁夏中强地震预报中的应用     

张东平 《地震》1994,(3):85-90

本文提出比值Ｒ分析计算方法，用其求解时间序列数据矩平差和标准差结构的分形，目的的于判定地震预报指标，作为实例，宁夏区和同心区的地震频度，最大震级，以及同心地办水氡观测数据的比值Ｒ随时间的分形变化进行了初步分析，证明本方法能为我国提供可信的震情信息。  相似文献