环渤海海岸带¹⁴C数据集（Ⅱ）   总被引：10，自引：2，他引：10       下载免费PDF全文

王宏  范昌福 《第四纪研究》2005,25(2):14-156

作为晚更新世与全新世地层年代测定的一种重要手段,¹⁴C测年被广泛应用于地质样品的年代测定。但对于¹⁴C数据的系统校正,迄今未得到应有的重视。文章在环渤海海岸带¹⁴C数据集(Ⅰ)的基础上,对所收集的421个由其他研究者获得的环渤海海岸带¹⁴C数据进行了系统校正。并讨论了百年、千年与万年尺度的¹⁴C数据校正效果。结果表明,直接测定值与系统校正值之间的差值常有数百年至两千年的差别。经统一校正的¹⁴C年龄,最大限度地接近样品太阳历纪年的“真实”年龄,从而有助于更加准确地重建该地区的晚更新世晚期以来的地质年代史,并可与考古纪年及其他测年方法获得的绝对年龄直接对比。  相似文献   

On the problem of model validation for predictive exposure assessments   总被引：1，自引：0，他引：1  

M. B. Beck  J. R. Ravetz  L. A. Mulkey  T. O. Barnwell 《Stochastic Hydrology and Hydraulics》1997,11(3):229-254

The development and use of models for predicting exposures are increasingly common and are essential for many risk assessments of the United States Environmental Protection Agency (EPA). Exposure assessments conducted by the EPA to assist regulatory or policy decisions are often challenged to demonstrate their “scientific validity”. Model validation has thus inevitably become a major concern of both EPA officials and the regulated community, sufficiently so that the EPA's Risk Assessment Forum is considering guidance for model validation. The present paper seeks to codify the issues and extensive foregoing discussion of validation with special reference to the development and use of models for predicting the impact of novel chemicals on the environment. Its preparation has been part of the process in formulating a White Paper for the EPA's Risk Assessment Forum. Its subject matter has been drawn from a variety of fields, including ecosystem analysis, surface water quality management, the contamination of groundwaters from high-level nuclear waste, and the control of air quality. The philosophical and conceptual bases of model validation are reviewed, from which it is apparent that validation should be understood as a task of product (or tool) design, for which some form of protocol for quality assurance will ultimately be needed. The commonly used procedures and methods of model validation are also reviewed, including the analysis of uncertainty. Following a survey of past attempts at resolving the issue of model validation, we close by introducing the notion of a model having maximum relevance to the performance of a specific task, such as, for example, a predictive exposure assessment.  相似文献   

Electromagnetic tomography: consistency of images and groundwater prospecting     

冯锐  马奎祥  郭鸿  刘昌铨  孙次昌  郝锦绮 《地震学报(英文版)》1997,10(5):649-661

Ｅｌｅｃｔｒｏｍａｇｎｅｔｉｃｔｏｍｏｇｒａｐｈｙ：ｃｏｎｓｉｓｔｅｎｃｙｏｆｉｍａｇｅｓａｎｄｇｒｏｕｎｄｗａｔｅｒｐｒｏｓｐｅｃｔｉｎｇＲＵＩＦＥＮＧ１）（冯锐）ＫＵＩＸＩＡＮＧＭＡ２）（马奎祥）ＨＯＮＧＧＵＯ３）（郭鸿）ＣＨＡＮＧＱＵＡＮ...  相似文献   

校准平行光管的新方法及其原理   总被引：1，自引：0，他引：1  

杨祖泽 《四川测绘》1997,20(1):17-20

平行光管是光学实验及计量检测的重要设备。为获得平行光，平行光管的分划权必需严格位于物镜后焦面上。如何将分划权准确地调整至物镜后焦面？传统的诸多方法中，或因设备难求，或受环境制约而难尽人意。本文提出一种校准平行光管的新方法并论证其原理  相似文献   

MAIS成象光谱仪飞行定标和反射率反演   总被引：7，自引：0，他引：7  

闵祥军  朱永豪  田庆久  王红梅 《遥感学报》1997,1(3):178-184

该文利用６Ｓ辐射传礓模型设计了一种可对ＭＡＩＳ成象光谱仪进行飞行研究定标和反射率反演的方法，并分析了成象光谱图象反经反演过程中影响反演精度的各种因素。这种方法的特点是地面同步测量中只采用一台仪器，同时获得了参考地物的反射率，大气光学厚度和大气垂直柱水汽含量。  相似文献   

An Improved Experimental Calibration of the Olivine-Spinel Geothermometer     

Li Jianping  Jacques Kornprobst  Daniel Vielzeuf  Jacques Fabriès 《中国地球化学学报》1995,14(1):68-77

The calibration of the olivine-spinel geothermometer by Fabries(1979) is commonly adopted by a number of petrologists.But the temperatures calculated in this way for ultramafic focks are significantly lower than those obtained by the pyroxene geothermometers.These O1-Sp temperatures are also lower than those measured experi-mentally in the natural system (four-phase lherzolite).Different rates of cation diffusion cannot fully account for these differences.The temperature deviation is actually related to the inconsistencies between natural and experimental data which support the calibration .A re-evaluation of the calibration is proposed on the basis of a set of new experimental data.  相似文献   

航空放射性测量标准模型及其应用     

蔡文良  丘汉昌  顾仁康 《铀矿地质》1989,(5)

本文对我国建成的第一个航空放射性测量标准模型的场地、规格、含量、均匀性、密度等主要参数作了简略说明,并就应用模型标定航空伽玛能谱测量系统进行了讨论。  相似文献   

平面型高纯锗低能γ谱仪测定铀矿样中^235U,^238U,^226Ra及^232Th含量     

林朝  张庆文 《铀矿地质》1989,5(2):117-120

本文对选用低能γ射线测定铀矿中的~(235)U、~(238)U、~(226)Ra、~(232)Th含量进行了讨论,提出了一种对样品进行自吸收校正的简单准确方法,对铀矿样中的~(235)U、~(238)U、或~(235)U/~(238)U比值测定获得了较高的分析精度和准确度。  相似文献   

用系统处理计算降水滞后型岩溶矿井涌水量     

成春奇  葛晓光 《安徽地质》1994,(4)

我国岩溶地区许多矿床的涌水量不仅随开拓深度（以下简称深度）与巷道长度（以下简称巷长）等因素的变化而变化，而且与降雨关系密切，并对降雨有明显滞后反映。当这些因素交织共存时，常规地下水动力学方法（即各种求解稳定流与非稳定流问题的解析法与数值法）及一般统计学方法等预测手段多难以奏效；本文试从系统观点出发，采用一些常用系统处理手法。  相似文献   

Laboratory calibration of Lacoste–Romberg type gravimeters by using a heavy cylindrical ring     

P. Varga  A. Hajósy  G. Csapó 《Geophysical Journal International》1995,120(3):745-757

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