云南姚安6.0级地震前异常特征

对2009年7月9日姚安6.0级强震前地震活动、前兆和相关宏观异常进行分析,发现这些异常对该地区6.0级以上强震的预报和研究具有一定的参考价值.     

Ultrasound‐Assisted Emulsification–Microextraction Combined with Graphite Furnace Atomic Absorption Spectrometry for the Determination of Trace Lead in Water

The ultrasound‐assisted emulsification–microextraction (USAEME) method was combined with graphite furnace atomic absorption spectrometry (GFAAS) for the determination of trace Pb using dithizone (H²DZ) as chelating reagent. Some effective parameters influenced the detection and microextraction, such as ashing temperature and atomization temperature, pH, extraction solvent, sample volume, extraction time, and extraction temperature were selected and optimized. After extraction, the calibration curves for Pb was in the concentration range of 0.1–10 ng mL^?1, and the linear equation was y = 0.097 x + 0.023 (R = 0.99). Under the optimized conditions, the detection limit of the method was 20 pg mL^?1 with an enrichment factor of 70 and the relative standards deviation (RSD) for seven determinations of 1 ng mL^?1 Pb was 11%. The proposed method was successfully applied to determine trace Pb in Yueya Lake water, pond water, and spiked samples. Furthermore, a certified reference material of Environment Water (GBW08607) was analyzed and the determined value was in good agreement with the certified value, which showed the accuracy, recovery, and applicability of the reported method.     

黄河内蒙古段洪峰特征及水沙关系变化

本文通过黄河头道拐站1950-2009 年水沙年系列进行突变点分析, 识别出1969 年、1986 年、1996 年3 个突变点, 将黄河内蒙古段水文过程划分为4 个时期。在此基础上, 利用内蒙古段6 个水文站长系列日流量、日含沙量及泥沙组成数据, 划分了各站的夏汛洪峰, 并统计分析了分期洪峰的水沙分布特征和洪峰水沙关系, 揭示出夏汛洪峰流量和输沙率逐渐减少的规律:1996-2006 年与1954-1968 年相比, 夏汛洪峰水沙量占全年水沙的比例都减少了约一半, 流量级频率与输沙率乘积的峰值对应的流量也降低了约一半。分析认为, 黄河内蒙古段夏汛洪峰特征阶段性变化既有大型水库的影响, 又有气候变化及人类活动的影响, 而且后者的作用越来越大。分析发现, 20 世纪90 年代以前, 黄河上游水沙变化只是改变了内蒙古段来沙中粗颗粒泥沙的水沙关系, 显示出大流量输送粗颗粒泥沙能力相对增强的趋向;进入内蒙段后, 通过泥沙冲淤调整, 分粒径组泥沙水沙关系变化比较复杂。近期在水沙条件巨大变化下, 河流的输沙特性并没有发生根本变化, 但是无论全沙还是分组沙, 水沙关系曲线变陡, 大流量输送泥沙能力相对增强。     

An insight into the Palmer drought mechanism based indices: comprehensive comparison of their strengths and limitations

Considering the drawbacks of the original Palmer drought severity index (PDSI) in terms of its simplified hydrologic algorithm and spatio-temporal inconsistency, we compare six variants of PDSI derived from different combinations of two hydrologic algorithms and three standard processes so as to provide deep insights into the individual impacts of hydrological processing and standardization on final PDSI values as well as their combined effects. Investigations are conducted in whole Yellow River basin. On basis of 52 years’ (1961–2012) hydro-meteorological data, comprehensive analysis on multiple drought characteristics are carried out for each PDSI variant, combined with comparison of three crucial intermediate variables of PDSI. Results show that variable infiltration capacity (VIC) model based modification in the hydrologic accounting section significantly improve drought trends with more reasonable spatial distributions presented. For the statistical characteristics of drought areas and frequency, comparable performance is found between VIC-based modification and self-calibrating standard procedure-based modification, though they are derived from different mechanisms. However, in case of the coupling of these two modifications, indices derived from combined modifications perform poorly than single modification-based indices with unexpected high frequency of extreme events detected in certain regions. This reflects the complicated mechanism of PDSI and it is essential to propose an appropriate standardization to match the hydrological algorithm and further improve the performance of relevant drought index. With the crucial findings mentioned above, this study is promising to provide some theoretical supports and serve as a competent reference for future PDSI based researches.     

准东博格达山山前带二叠系芦草沟组重油的发育特征及其指示意义

二叠系芦草沟组是准噶尔盆地东部地区最重要的烃源岩层系和勘探目的层系之一。2013年中国地质调查局油气资源调查中心在准噶尔盆地南缘博格达山山前带实施的油页岩调查井JZK1井钻探过程中,发现二叠系芦草沟组重油。通过对JZK1重油和岩心样品有机地球化学的测试数据研究表明:二叠系重油原油演化程度适中,主要赋存于岩石裂缝中,且经历过后期生物降解作用;油源对比指示,原油来自于芦草沟组本身,属自生自储型油藏。据此推测西起乌鲁木齐市雅玛里克山,东至奇台的白杨沟,断续延长136 km,宽2~10 km,分布面积约2×10⁴ km²的芦草沟组均为下步油气勘探的有利区。基于钻井和过井地震测线的解释结果,指出存在推覆体上盘和推覆体下盘两个勘探领域,且推覆体下盘的原生油藏领域埋藏深、规模大,是下步勘探重点领域。     

变换光谱数据对土壤氮素PLSR模型的影响研究

光谱数据变换对消除背景、噪音影响以及提取光谱特征有重要的作用,是光谱数据分析过程中的必要步骤。为了研究光谱变换处理对土壤氮素PLSR模型的影响精度,并选择最佳光谱变换处理方法,本文对原始光谱数据进行了15种典型光谱变换,通过比较不同变换光谱与土壤氮素的相关性,实现土壤氮素的PLSR精确诊断,并综合评定最佳光谱数据变换方法。结果表明,涉及微分处理后的光谱变换,尤其是先进行开方（T₈、T₁₁）、对数（T₆、T₁₂）等变换后再进行微分处理,可提高其与土壤氮素的相关性。在引入较少因子变量个数的条件下,该方法使因变量解释量达到了98%。综合考虑模型的校正、验证效果及模型复杂度（模型最佳因子变量个数）,可得出光谱平方根的一阶微分变换处理（T₈）为最佳的土壤光谱变换算法。该条件下的土壤氮素的校正模型表现为R²=0.985、RMSE_C=0.000132、F_n=6,验证模型的表现为R²=0.9853、RMSE_V=0.000162,结果表明基于T₈的光谱数据变换可实现本试验条件下土壤氮素的光谱估算。另外,可以考虑将原始光谱的一阶微分（T₉）、对数和对数倒数的一阶微分（T₆、T₇）以及平方根和对数的二阶微分（T₁₁、T₁₂）作为光谱数据变换方法。本文研究结果可为土壤氮素估算和光谱数据预处理提供技术参考。     

闪锌矿流体包裹体显微红外测温及其矿床成因意义——以云南会泽超大型富锗银铅锌矿床为例

显微红外测温是利用红外显微镜研究不透明半透明矿物的流体包裹体丰度和分布特征,并与冷热台相结合进行流体包裹体显微测温分析的一种有效的新技术。云南会泽超大型富锗银铅锌矿床是分布于川滇黔接壤区典型的会泽型(HZT)铅锌矿床。本文以该矿床的闪锌矿、方解石流体包裹体为例,应用显微红外测温技术发现闪锌矿中发育大量流体包裹体,按其相态可分为6类:纯气相(V)、富液相气液两相(L+V)、富气相气液两相(L+V)、纯液相(L)、含子矿物三相(L+V+S)、含CO₂三相(L_CO2+L_H2O+V_CO2)包裹体,而在热液方解石中仅发现富液相气液两相(L+V)、纯液相(L)包裹体。闪锌矿中的流体包裹体均一温度集中在2个区间:150~221℃和320~364℃;而盐度变化范围较大,主要集中于3个区间:12.0%~18.0%、5.0%~11.0%、1.1%~5.0%。不同世代闪锌矿流体包裹体均一温度大致反映成矿流体演化的全过程,而方解石流体包裹体均一温度主要反映成矿流体演化的中晚阶段,而且与脉石矿物(方解石)共生的闪锌矿流体包裹体均一温度也高于方解石包裹体均一温度;反映了闪锌矿流体包裹体较方解石更能反映成矿流体的信息,进一步揭示从早成矿阶段到晚成矿阶段,成矿流体大致经历了中高温-中盐度→中低温-中盐度→中低温-中低盐度的演化过程。通过压力校正后的流体包裹体捕获温度反映了早成矿阶段成矿流体呈中高温,进一步证实了该矿床并非低温矿床。通过矿床对比研究,不仅反映了该矿床明显不同于典型的MVT铅锌矿床,而且表明了显微红外测温技术为该类矿床成矿流体p-T-x条件及矿床成因的研究提供了新方法与途径,并将在金属矿床成矿流体的研究领域发挥重要作用。