The Long‐Term Robustness and Stability of Consensus Values as Composition Location Estimators for a Typical Geochemical Test Material in the GeoPT Proficiency Testing Programme     

Peter C. Webb  Philip J. Potts  Michael Thompson  Stephen A. Wilson  Charles J. B. Gowing 《Geostandards and Geoanalytical Research》2019,43(3):397-408

Re‐issuing the same test material, its true identity unknown to participants, in two rounds of the GeoPT proficiency testing programme 18 years apart has demonstrated remarkable similarity, and therefore stability, of consensus values independently estimated for over fifty measurands in each round. A comparison of the two data sets, GeoPT5 (AMH‐1) from 1999 and GeoPT41 (ORA‐1) from 2017, shows that corresponding consensus values, rigorously derived by current procedures for complete compatibility, are for the most part statistically indistinguishable when account is taken of their associated uncertainties. Inferences that may be drawn from this exceptional agreement include: (a) the consensus estimation procedure was robust and gave consistent results; (b) overall, the balance of the contributed data was unaffected by significant changes in: (i) the populations of laboratories participating, (ii) the proportions of laboratories producing results by different techniques, (iii) the manner in which systems were calibrated, or (iv) the aspirations of laboratories to attain higher quality results over time; and (c) unsurprisingly perhaps, that the test material itself had remained stable and unchanged during that time. Additionally, a statistical comparison of the original values for AMH‐1 with consensus values derived by current procedures demonstrates that they are also effectively indistinguishable.  相似文献   

地磁台站数字与模拟观测报告一致性分析及影响因素初探     

李永华  杨冬梅  赵永芬  张素琴 《地震地磁观测与研究》2004,25(1):57-62

对2002年度地磁台站模拟观测系统和数字观测系统观测报告中的D、H、Z三分量日均值的一致性进行了分析,并对其影响因素进行了初步探讨,将有助于模拟观测系统向数字观测系统的顺利过渡。  相似文献   

Analysis of inter-gauge dependence by Kendall’s τK, upper tail dependence coefficient, and 2-copulas with application to rainfall fields   总被引：1，自引：1，他引：0  

Francesco Serinaldi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(6):671-688

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Turbulent dynamo near tachocline and reconstruction of azimuthal magnetic field in the solar convection zone     

V. N. Krivodubskij 《Astronomische Nachrichten》2005,326(1):61-74

In order to extend the abilities of the αΩ dynamo model to explain the observed regularities and anomalies of the solar magnetic activity, the negative buoyancy phenomenon and the magnetic quenching of the α effect were included in the model, as well as newest helioseismically determined inner rotation of the Sun were used. Magnetic buoyancy constrains the magnitude of toroidal field produced by the Ω effect near the bottom of the solar convection zone (SCZ). Therefore, we examined two “antibuoyancy” effects: i) macroscopic turbulent diamagnetism and ii) magnetic advection caused by vertical inhomogeneity of fluid density in the SCZ, which we call the ∇ρ effect. The Sun's rotation substantially modifies the ∇ρ effect. The reconstruction of the toroidal field was examined assuming the balance between mean‐field magnetic buoyancy, turbulent diamagnetism and the rotationally modified ∇ρ effect. It is shown that at high latitudes antibuoyancy effects block the magnetic fields in the deep layers of the SCZ, and so the most likely these deep‐rooted fields could not become apparent at the surface as sunspots. In the near‐equatorial region, however, the upward ∇ρ effect can facilitate magnetic fields of about 3000 – 4000 G to emerge through the surface at the sunspot belt. Allowance for the radial inhomogeneity of turbulent velocity in derivations of the helicity parameter resulted in a change of sign of the α effect from positive to negative in the northern hemisphere near the bottom of the SCZ. The change of sign is very important for direction of the Parker's dynamo‐waves propagation and for parity of excited magnetic fields. The period of the dynamo‐wave calculated with allowance for the magnetic quenching is about seven years, that agrees by order of magnitude with the observed mean duration of the sunspot cycles. Using the modern helioseismology data to define dynamo‐parameters, we conclude that north‐south asymmetry should exist in the meridional field. At low latitudes in deep layers of the SCZ, the αΩ dynamo excites most efficiency the dipolar mode of the meridional field. Meanwhile, in high‐latitude regions a quadrupolar mode dominates in the meridional field. The obtained configuration of the net meridional field is likely to explain the magnetic anomaly of polar fields (the apparent magnetic “monopole”) observed near the maxima of solar cycles. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

GQLup and its common proper motion companion     

M. Mugrauer  R. Neuhuser 《Astronomische Nachrichten》2005,326(8):701-708

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Geochronological characterization and petrogenesis of granitoids in the Ryoke belt, Southwest Japan Arc: constraints from K–Ar, Rb–Sr and Sm-Nd systematics     

Masaki Yuhara  Hiroo Kagami and  Keisuke Nagao 《Island Arc》2000,9(1):64-80

Abstract Rb–Sr and K–Ar chronological studies were carried out on granitic and metamorphic rocks in the Ina, Awaji Island and eastern Sanuki districts, Southwest Japan to investigate the timing of intrusion of the granitoids in the Ryoke belt. Intrusions of 'younger' Ryoke granitic magmas took place in the Ina district between 120 Ma and 70 Ma, and cooling began immediately after the emplacement of the youngest granitic bodies. Igneous activity in Awaji Island was initiated at 100 Ma and continued to 75 Ma. Along-arc variations of Rb–Sr whole-rock isochron ages suggest that magmatism began everywhere in the Ryoke and San-yo belts at almost the same time ( ca 120 Ma). The last magmatism took place in the eastern part of both belts. Rb–Sr and K–Ar mineral ages for the granitoids young eastwards. The age data suggest that the Ryoke belt was uplifted just after the termination of igneous activity. Initial Sr and Nd isotopic ratios for the Ryoke granitoids indicate that most were derived from magmas produced in the lower crust and/or upper mantle with uniform Sr and Nd isotopic compositions. Several granitoids, however, exhibit evidence of assimilation of Ryoke metamorphic rocks or older Precambrian crustal rocks beneath the Ryoke belt.  相似文献   

核心型钢混凝土柱的轴压比限值试验研究   总被引：2，自引：0，他引：2  

刘阳  郭子雄  张志伟 《地震工程与工程振动》2008,28(3):82-86

基于界限破坏时的内力平衡条件,推导了核心型钢混凝土柱轴压比限值的理论计算公式,计算分析了配钢率、混凝土强度等级、柱截面尺寸等因素对核心型钢混凝土柱轴压比限值的影响。进行了5个1/2比例模型柱试件的低周反复加载试验,验证了配置核心型钢对提高混凝土柱的抗震性能和轴压比限值的有效性。计算和试验结果表明,在混凝土柱中配置一定数量的核心型钢,可以有效提高轴压比限值。本文建议的方法可以较为合理地确定核心型钢混凝土柱的轴压比限值,供工程实践参考。  相似文献   

川滇活动地块东边界强震危险性研究   总被引：39，自引：7，他引：32       下载免费PDF全文

易桂喜  闻学泽  苏有锦 《地球物理学报》2008,51(6):1719-1725

以川滇活动地块东边界为例,利用最近31年的地震资料,根据精细b值计算结果,研究该边界断裂带的应力空间分布及其强震危险性. 研究结果显示：（1）沿川滇活动地块东边界,b值空间分布显示在不同断裂以及同一断裂不同断裂段存在较大差异,从而反映出应力积累水平的空间差异.（2）小江断裂带主干断裂上的嵩明凹凸体及存在于主干断裂附近巧家与东川间以及嵩明北西的2个凹凸体、存在于安宁河断裂冕宁附近和则木河断裂西昌附近的凹凸体以及位于鲜水河断裂中南段道孚—乾宁间大尺度的凹凸体将是川滇活动地块东边界未来大震或强震的震源区.  相似文献   

岩体稳定性评价的模糊概率方法     

刘章军  叶燎原 《岩土力学》2006,27(Z2):186-190

岩体稳定性受多种不确定性因素的影响,不仅具有随机性,也具有模糊性,属于模糊概率的范畴,利用经典的模糊综合评判方法进行研究将会导致不合理的结果。在模糊概率理论的基础上,建立了一类新的岩体稳定性综合评价方法——模糊概率方法,并提出了模糊权重的概念,从而避免了权重取值带来的不确定性。结合所选取的5个影响岩体稳定性的因素,建立了这5个影响因素的隶属函数与模糊权重;利用该方法对某一地下岩体工程进行分析,并与其他方法评价的结果进行比较,表明了其方法的合理性与可靠性。  相似文献   

一般多层准地转基本流的扰动发展 与非线性稳定性     

宋士吉  刘家琦  刘秦玉 《大气科学》2000,24(3):412-426

考察了一般多层准地转模式中初值与参数共同扰动的情形。在初始扰动场仅依赖于初始扰动位势涡度、初始扰动边界速度环量与扰动参数的条件下,给出了扰动能量、扰动位涡拟能发展上（下）界精细的显式估计。进而在Lyapunov意义下广义非线性稳定性概念的基础上,得到了对应于Arnold 第二定理的非线性稳定性判据。本文工作推广了仅考虑模式中初值扰动情形所得到的相应结果。  相似文献