蒸气收集脉冲进样流动注射氢化物发生－原子荧光法测定痕量锑     

林守麟  邱海鸥  汤志勇 《岩矿测试》1994,(2)

研究了流动注射氢化物发生－原子荧光测定矿石中Ｓｂ的方法，提出用蒸气收集脉冲进样技术，较大地提高了氢化物发生法的灵敏度和检测能力。标准参考样品的分析结果与推荐值吻合，精密度（ＲＳＤ）和检出限分别为５．１％（８ｎｇ／ｍｌ，ｎ＝９）和０．１９ｎｇ／ｍｌ。测定速度为１２０样／ｈ。  相似文献   

核地球物理学的X射线荧光技术在我国固体矿产资源中的研究与应用     

章晔  谢庭周 《地球物理学报》1989,32(4):441-449

本文概述:1.理论研究及基体效应的校正;2.本文作者设计与发展的HYX-1轻便型X射线荧光仪、HYX-2轻便型双道X射线荧光仪、HYX-3微型机400道X射线荧光仪、JXY-1X射线荧光测井仪以及用于各型轻便型X射线荧光仪的找金矿滤波器;3.用于Fe、Mn、Cu、Ni、Cr、Zn、Pb、Sr、Mo、As、Sn、sb、Ba、W、Hg、Au、K、P等矿种的勘查或开采中的测定。实践表明,核地球物理学的X射线荧光技术在勘探和生产中是有效而经济的工具。  相似文献   

核物探X射线荧光技术在Pb、Zn矿勘查中的研究与应用     

葛良全  谢庭周 《现代地质》1994,8(3):335-341

本文论述了应用核物探Ｘ射线荧光技术勘查Ｐｂ、Ｚｎ矿的物理基础、地质－地球化学依据和方法技术。实践表明，本技术可以现场快速进行土壤次生晕测量、岩石地球化学测量、粉末样品测量和原位测定Ｐｂ、Ｚｎ品位．  相似文献   

水库群防洪调度的逐次优化方法   总被引：16，自引：1，他引：16       下载免费PDF全文

都金康  周广安 《水科学进展》1994,5(2):134-141

针对防洪系统的具体问题,分析了并联水库群下泄流量与河道防洪控制点洪峰流量之间的内在联系,根据“先泄、后蓄、再分洪”的一般洪水调度原则,提出了水库群拱水调度模型及其逐次优化解法。该方法成功地实现了水库群之间以及水库群与区间汇流的错峰,为洪水实时调度及防洪系统规划提供了一套简捷、高效而又符合实际的模型和解法。  相似文献   

用X射线光谱法测定锰的X射线发射谱的细结构及锰的价态分析   总被引：3，自引：2，他引：3  

谭秉和  张香荣 《岩矿测试》1994,13(3):169-174

在普通的ＸＲＦ光谱仪上测定金属锰，氧化锰、锰的化合物中ＭｎＫβ发射谱带，经谱数据处理获得了谱线的轮廓线及谱峰参数（峰位，峰高，峰宽，峰宽，峰函数比例因子，不对称因子）；研究了谱参数与价态间的关系。结果表明ＭｎＫβ谱带结构与化合价，氧化数，化学键及配位状况有关，利用所得出的规律对太平洋锰结核的价态作了定性测定，并用谱峰分解法对Ｍｎ３Ｏ４试样进行化学价态定量分析的浓度量，得到满意的结果。  相似文献   

利用夫琅和费暗线探测自然光条件下的植被光合作用荧光研究   总被引：1，自引：3，他引：1  

刘良云  张永江  王纪华  赵春江 《遥感学报》2006,10(1):130-137

自然光照条件下测定的植被反射的辐照度光谱既包括太阳光诱导荧光的发射光谱，又包括叶片对入射光的反射光谱，研究如何从冠层光谱中提取荧光光谱有十分重要的应用价值。首先，论文介绍了夫琅和费暗线探测自然光条件下的光合作用荧光的基本原理和方法。其次，将太阳大气的夫琅和费暗线拓展到地球大气，发现地物光谱仪测定的冠层辐照度光谱中688nm和760nm两个氧气吸收形成的夫琅和费暗线特征明显，且荧光较强，所以利用这两个波段的夫琅和费暗线可以探测自然光条件下的光合作用荧光。第三，研究并分析了夫琅和费暗线方法计算的688nm和760nm波段的荧光特性，结果表明该方法计算的荧光是可靠的，它与光合有效辐射（PAR）关系密切，复相关系数达到了0．9；冬小麦冠层荧光光谱在760nm和688nm波段的荧光大小基本相等，而地锦冠层荧光光谱在688nm波段的荧光强度是760nm的3倍左右，表明荧光光谱能够更加敏感地反映植被物种或生理生化状况的差别。最后，将夫琅和费暗线方法计算的688nm和760nm波段的荧光数据与激光脉冲调制荧光仪测定Fv／Fm荧光参数进行了统计分析，结果表明它与Fv／Fm存在极显著的负相关关系。所以利用夫琅和费暗线方法能够探测植被冠层荧光，并有可能替代传统的测定方法，并推广到航空航天平台，实现荧光探测从接触式点测量方式到航空或卫星遥感大面积监测的技术飞越。  相似文献   

Forecasting shield pressures at a longwall face using artificial neural networks     

Debasis Deb  Akshay Kumar  Rajat Pal Singh Rosha 《Geotechnical and Geological Engineering》2006,24(4):1021-1037

Leg pressure data from all shields of a longwall face are monitored and recorded in the surface computer. An algorithm is developed to detect peak pressures or periodic roof weightings from these pressure data. The intensities and locations of periodic roof weighting are further analyzed using artificial neural network for forecasting of forthcoming shield pressures. The network was trained using data 153 m (500 ft) of face advance. Shield pressures are forecasted for the successive nine mining cycles or approximately 9 m of face advancement. The results obtained validate the efficacy of the developed model.  相似文献   

Determination of Hg and MeHg complexation with dissolved organic matter by fluorescence quenching titration     

Pingqing FU Fengchang WU Feiyue WANG 《中国地球化学学报》2006,25(B08):264-265

In natural waters inorganic mercury （Hg） and methylmercury （MeHg） are complexed with a variety of inorganic and organic ligands, such as OH^-, Cl^-, sulfide, thiols, and dissolved organic matter （DOM）. The bioavailability and toxicity of Hg and MeHg are related to their speciation, instead of their total concentrations. Among these species, Hg-DOM and MeHg-DOM complexes are the least known, due to the complexity and site-specificity of DOM in natural waters. Here we report the complexation between DOM and Hg or MeHg using fluorescence spectroscopy. The Suwannee River fulvic acid, peat humic acid, amino acid typotophan, and natural organic matter from the Suwannee River, Nordic River, and Delta Marsh were studied at their respective excitation/emission maxima,  相似文献   

How High Are the P-T Conditions for Paleoproterozoic Metamorphism of the Huangtuling Felsic Granulite, North Dabieshan, Central China？   总被引：1，自引：0，他引：1  

陈能松  龚松林孙敏  杨勇刘嵘 《中国地质大学学报(英文版)》2006,17(4):291-301

This paper is supported by the Special Doctoral Grant of the Ministry of Education of China （No. 98049114） and the National Natural Science Foundation of China （No. 49972023）.  相似文献   

Carbon and nitrogen fixation differ between successional stages of biological soil crusts in the Colorado Plateau and Chihuahuan Desert   总被引：13，自引：2，他引：13  

D.C. Housman  H.H. Powers  A.D. Collins  J. Belnap 《Journal of Arid Environments》2006,66(4):620-634

Biological soil crusts (cyanobacteria, mosses and lichens collectively) perform essential ecosystem services, including carbon (C) and nitrogen (N) fixation. Climate and land-use change are converting later successional soil crusts to early successional soil crusts with lower C and N fixation rates. To quantify the effect of such conversions on C and N dynamics in desert ecosystems we seasonally measured diurnal fixation rates in different biological soil crusts. We classified plots on the Colorado Plateau (Canyonlands) and Chihuahuan Desert (Jornada) as early (Microcoleus) or later successional (Nostoc/Scytonema or Placidium/Collema) and measured photosynthesis (P_n), nitrogenase activity (NA), and chlorophyll fluorescence (F_v/F_m) on metabolically active (moist) soil crusts. Later successional crusts typically had greater P_n, averaging 1.2–1.3-fold higher daily C fixation in Canyonlands and 2.4–2.8-fold higher in the Jornada. Later successional crusts also had greater NA, averaging 1.3–7.5-fold higher daily N fixation in Canyonlands and 1.3–25.0-fold higher in the Jornada. Mean daily F_v/F_m was also greater in later successional Canyonlands crusts during winter, and Jornada crusts during all seasons except summer. Together these findings indicate conversion of soil crusts back to early successional stages results in large reductions of C and N inputs into these ecosystems.  相似文献