连续运行GPS定位服务系统的探讨   总被引：1，自引：0，他引：1  

朱国峰 《测绘与空间地理信息》2008,31(2):108-110

介绍了连续运行GPS定位服务的概念、实现模式及其在测绘行业中的应用。  相似文献   

GPS RTK校准检测试验场建设的研究     

彭江华  孙忠胜  贺浩 《地理空间信息》2008,6(3):19-20

叙述了GPSRTK接收机校准检测试验场建设的方法,介绍了GPSRTK接收机校准检测的步骤,提出了GPSRTK校准检测的项目和结果判定方法,为未来的GPSRTK国家检定规程的出台做了有益地探索。  相似文献   

Zircon M257 ‐ a Homogeneous Natural Reference Material for the Ion Microprobe U‐Pb Analysis of Zircon     

Lutz Nasdala  Wolfgang Hofmeister  Nicholas Norberg  James M. Martinson  Fernando Corfu  Wolfgang Dörr  Sandra L. Kamo  Allen K. Kennedy  Andreas Kronz  Peter W. Reiners  Dirk Frei  Jan Kosler  Yusheng Wan  Jens Götze  Tobias Häger  Alfred Kröner  John W. Valley 《Geostandards and Geoanalytical Research》2008,32(3):247-265

We introduce and propose zircon M257 as a future reference material for the determination of zircon U‐Pb ages by means of secondary ion mass spectrometry. This light brownish, flawless, cut gemstone specimen from Sri Lanka weighed 5.14 g (25.7 carats). Zircon M257 has TIMS‐determined, mean isotopic ratios (2s uncertainties) of 0.09100 ± 0.00003 for ²⁰⁶pb/²³⁸U and 0.7392 ± 0.0003 for ²⁰⁷pb/²³⁵U. Its ²⁰⁶pb/²³⁸U age is 561.3 ± 0.3 Ma (unweighted mean, uncertainty quoted at the 95% confidence level); the U‐Pb system is concordant within uncertainty of decay constants. Zircon M257 contains ～ 840 μg g^?1 U (Th/U ～ 0.27). The material exhibits remarkably low heterogeneity, with a virtual absence of any internal textures even in cathodoluminescence images. The uniform, moderate degree of radiation damage (estimated from the expansion of unit‐cell parameters, broadening of Raman spectral parameters and density) corresponds well, within the “Sri Lankan trends”, with actinide concentrations, U‐Pb age, and the calculated alpha fluence of 1.66 × 10¹⁸ g^?1. This, and a (U+Th)/He age of 419 ± 9 Ma (2s), enables us to exclude any unusual thermal history or heat treatment, which could potentially have affected the retention of radiogenic Pb. The oxygen isotope ratio of this zircon is 13.9%o VSMOW suggesting a metamorphic genesis in a marble or calc‐silicate skarn.  相似文献   

Composition-Induced Variations in SIMS Instrumental Mass Fractionation during Boron Isotope Ratio Measurements of Silicate Glasses     

Martin Rosner  Michael Wiedenbeck  Thomas Ludwig 《Geostandards and Geoanalytical Research》2008,32(1):27-38

An analytical artefact is reported here related to differences in instrumental mass fractionation between NIST SRM glasses and natural geological glasses during SIMS boron isotope determinations. The data presented demonstrated an average 3.4‰ difference between the NIST glasses and natural basaltic to rhyolitic glasses mainly in terms of their sputtering-induced fractionation of boron isotopes. As no matrix effect was found among basaltic to rhyolitic glasses, instrumental mass fractionation of most natural glass samples can be corrected by using appropriate glass reference materials. In order to confirm the existence of the compositionally induced variations in boron SIMS instrumental mass bias, the observed offset in SIMS instrumental mass bias has been independently reproduced in two laboratories and the phenomenon has been found to be stable over a period of more than one year. This study highlights the need for a close match between the chemical composition of the reference material and the samples being investigated.  相似文献   

Recommended Values of ²³⁹Pu, ²⁴⁰Pu and ^239+240Pu Concentrations in Reference Material IAEA-315 (Marine Sediment) Estimated by Thermal Ionisation Mass Spectrometry, Inductively Coupled Plasma-Mass Spectrometry and Alpha Spectrometry     

Taeko Shinonaga  Helmuth Aigner  Dilani Klose  Peter Spinder  Heinz Fröschl  David Donohue 《Geostandards and Geoanalytical Research》2008,32(1):93-101

The recommended concentrations of ²³⁹Pu, ²⁴⁰Pu and ^239+240Pu in reference material IAEA‐315 (marine sediment) were estimated by three analytical methods: isotope dilution thermal ionisation mass spectrometry (TIMS), isotope dilution inductively coupled plasma‐mass spectrometry (ICP‐MS) and alpha spectrometry. The determination of ²³⁹Pu and ²⁴⁰Pu (^239+240Pu by alpha spectrometry) was carried out with samples from randomly selected bottles using each method. Plutonium‐238 was also measured by alpha spectrometry. A plutonium‐242 reference material was used as a spike for the quantitative analysis. The influence of ²⁴²Pu in the samples was therefore calculated; however, this contribution was less than the range of uncertainty and did not influence the final results. The obtained data were statistically analysed using variance component analysis and paired comparison. The combined standard uncertainties from “method/measurement”, “bottle” and “sub‐sample” were in the order of 3 to 6%. The main contributions to the uncertainty were from the material heterogeneity and from systematic differences between methods. Based on this study with twenty‐seven analyses using 10–14 g sample mass, concentrations of (38 ± 3) Bq kg^?1, (28 ± 3) Bq kg^?1 and (66 ± 4) Bq kg^?1 are proposed as recommended values for ²³⁹Pu, ²⁴⁰Pu and ^239+240Pu, respectively, and (9.5 ± 0.4) Bq kg^?1 for ²³⁸Pu as an information value in reference material IAEA‐315. In mass concentration units, these amount to (16.4 ± 1.2) ng kg^?1, (3.3 ± 0.4) ng kg^?1 and (0.015 ± 0.003) ng kg^?1 for ²³⁹Pu, ²⁴⁰Pu and ²³⁸Pu, respectively. The certified reference materials NIST 4350B and NIST 4354 were also analysed by TIMS for quality assurance of the method used in this study.  相似文献   

应用GPS数据与重力数据确定大地水准面     

于小平  张廷玉  刘财  陈增宝  许惠平  庞贺民 《吉林大学学报(地球科学版)》2008,38(5)

作为GPS/重力边值问题理论及方法的应用,在对GPS/重力方法确定(似)大地水准面的原理进行简要介绍与分析的基础上,利用收集到的N区的600个GPS/重力数据和48个高精度GPS水准数据,计算出该区域的(似)大地水准面。通过拟合法和系统差直接改正法进行的精度分析表明,应用GPS/重力数据结合水准方法确定的该地区(似)大地水准面的精度达到厘米级精度。  相似文献   

Extreme value analysis of diamond-size distributions     

J. Caers  P. Vynckier  J. Beirlant  L. Rombouts 《Mathematical Geology》1996,28(1):25-43

Extreme value analysis provides a semiparametric method for analyzing the extreme long tails of skew distributions which may be observed when handling mining data. The estimation of important tail characteristics, such as the extreme value index, allows for a discrimination between competing distribution models. It measures the thickness of such long tailed distributions, if only a limited sample is available. This paper stresses the practical implementation of extreme value theory, which is used to discriminate a lognormal from a mixed lognormal distribution in a case study of size distributions for alluvial diamonds.  相似文献   

浙闽山区茶叶生产基地评价的探讨   总被引：6，自引：0，他引：6  

华熙成 《地理研究》1994,13(3):98-103

茶叶基地的评价包括对基地的自然和经济条件的评估,应用系统分析方法,将自然和经济条件进行定量的综合评估,用综合评价值区分基地间的差异,最后定性与定量相结合,提出茶叶生产基地的合理布局.  相似文献   

云南兰坪-思茅盆地生物地球化学找钾技术方法研究初探     

伯英  刘成林  沈力建  丁婷 《地质学报》2022,96(7):2626-2633

在生物地球化学和“深穿透”理论的指导下,在兰坪-思茅盆地勐野井钾盐矿区及周边开展了生物地球化学找钾技术方法的探索性研究。沿江城县勐野井钾盐矿区及周边一线,对乔木类植物叶子进行了取样,分析,数据处理,特征指标筛选,获得了研究区植物样品主量和微量组分含量背景值,初步圈定了异常区,与以往圈定的找钾远景区较吻合。该区生物地球化学找钾技术取得较好的效果,今后还需扩大采样区域,获得更多样本数据,将找钾特征指标及其异常值的阈值进一步补充完善。  相似文献   

多硅白云母b₀值对澜沧群中压和高压变质的反映   总被引：1，自引：0，他引：1       下载免费PDF全文

宋仁奎  应育浦 《地质科学》1997,32(1):56-64

多硅白云母b₀值作为相对地质压力计的理论和方法,已受到各国地质学家的普遍重视。本文以澜沧群多硅白云母作为研究对象,提出运用多硅白云母b₀值区分不同压力变质的方法。研究结果表明澜沧群经历了中压和高压变质作用,两期变质的多硅白云母b₀值分别为9.027Å和9.047Å。  相似文献