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721.
722.
用NITON矿石元素分析仪测定圈定镍矿体地表出露边界,能基本查明矿体数量、规模、成矿规律、成矿地质条件,达到了快速评价矿床,能取得较好的找矿成果。 相似文献
723.
水稻土中重金属元素Cd、Pb的竞争吸附
——以长株潭地区水稻土为例 总被引:3,自引:0,他引:3
对中国南方的3个水稻土样品进行了Cd、Pb单一离子和混合离子吸附特点的研究。结果表明,3个水稻土样品中Cd、Pb的吸附特点都相似,Langmuir等温方程可很好地描述Cd、Pb的吸附等温线。3个土壤样品中,有较高pH值和较低有机物、CEC浓度、粘土含量、高岭石含量的2个土壤样品对Cd、Pb有较大的吸附量,且其等温吸附拟合的最大吸附量(B)也较大。在两组分混合溶液中,尽管共存离子的存在影响了土壤对单一离子的吸附,同时土壤对Cd的吸附在一定程度上受影响的程度大,但3个土壤样品都表现出对Pb有强的吸附能力。在3个土壤样品中,Langmuir等温方程中Pb的健合能常数(K)都大于Cd的健合能常数(K),混合溶液中的K值高于单一溶液的K值,表明2种金属离子对吸附位点的竞争提高了特定吸附位点的保持力,使金属离子在土壤中特定位点的吸附更加坚固。 相似文献
724.
利用双流国际机场2013—2018年的逐小时气象观测资料、欧洲中心ERA-interim逐6小时再分析资料、成都市气象局多普勒天气雷达产品资料,运用统计学方法分析双流机场雷暴月变化和日变化特征,并利用相关性分析筛选出双流机场雷暴天气预报因子,在此基础上基于二级逻辑回归法建立潜势预报模型(预报方程和消空方程),最后进行数据的回代检验。结果表明:对流有效位能、K指数、850 hPa比湿、850与500 hPa假相当位温差、回波顶高、1.5º仰角基本反射率、3.4º仰角基本反射率、垂直累积液态水含量为雷暴天气的主要预报因子,据此建立的潜势预报模型对双流机场雷暴天气的预报具有一定指示性,且综合来看在夏季的预报效果更好。 相似文献
725.
726.
对于具有复杂场景的遥感影像,提出了基于各向异性扩散特征保持平滑的简化LEGION算法,弥补传统LEGION图像分割算法对噪声敏感的不足。对于多(高)光谱影像,则采用马氏距离计算光谱向量间的连接权得到扩展LEGION算法进行分割。实验结果表明,LEGION算法较传统的图像分割方法对单波段灰度遥感影像目标及其重要细节部分的分割效果更显著;扩展LEGION算法适用于多光谱遥感影像分割。 相似文献
727.
Relationship Between the Western Pacific Subtropical High and the Subtropical East Asian Diabatic Heating During South China Heavy Rains in June 2005
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Based on the daily NCEP/NCAR reanalysis data, the position variation of the western Pacific subtropical high (WPSH) in June
2005 and its relation to the diabatic heating in the subtropical East Asia are analyzed using the complete vertical vorticity
equation. The results show that the position variation of the WPSH is indeed associated with the diabatic heating in the subtropical
East Asian areas. In comparison with June climatology, stronger heating on the north side of the WPSH and relatively weak
ITCZ (intertropical convergence zone) convection on the south side of the WPSH occurred in June 2005. Along with the northward
movement of the WPSH, the convective latent heating extended northward from the south side of the WPSH. The heating to the
west of the WPSH was generally greater than that inside the WPSH, and each significant enhancement of the heating field corresponded
to a subsequent westward extension of the WPSH. In the mid troposphere, the vertical variation of heating on the north of
the WPSH was greater than the climatology, which is unfavorable for the northward movement of the WPSH. On the other hand,
the vertical variation of heating south of the WPSH was largely smaller than the climatology, which is favorable for the anomalous
increase of anticyclonic vorticity, leading to the southward retreat of the WPSH. Before the westward extension of the WPSH
in late June 2005, the vertical variation of heating rates to (in) the west (east) of the WPSH was largely higher (lower)
than the climatology, which is in favor of the increase of anticyclonic (cyclonic) vorticity to (in) the west (east) of the
WPSH, inducing the subsequent westward extension of the WPSH. Similar features appeared in the lower troposphere. In a word,
the heating on the north-south, east-west of the WPSH worked together, resulting in the WPSH extending more southward and
westward in June 2005, which is favorable to the maintenance of the rainbelt in South China. 相似文献
728.
Results obtained by SASW and PS-logging (in-hole) seismic techniques are compared with the relatively new ReMi (Refraction microtremor) method at a common site with a well-known soil profile: a recently constructed high-speed railway embankment. PS-logging is the most accurate technique in identifying the soil profile of the embankment followed by Re-Mi and SASW. Mean shear wave velocity estimations are also higher for PS-logging, followed by SASW and ReMi, while mean deviation is similar in each technique. The ReMi technique has provided very accurate results in the study of the embankment profile, which in addition to its high operability and its fast data processing, makes it a very convenient technique for extensive geotechnical surveys. 相似文献
729.
F.A. Radu N. Suciu J. HoffmannA. Vogel O. Kolditz C.-H. ParkS. Attinger 《Advances in water resources》2011,34(1):47-61
This work deals with a comparison of different numerical schemes for the simulation of contaminant transport in heterogeneous porous media. The numerical methods under consideration are Galerkin finite element (GFE), finite volume (FV), and mixed hybrid finite element (MHFE). Concerning the GFE we use linear and quadratic finite elements with and without upwind stabilization. Besides the classical MHFE a new and an upwind scheme are tested. We consider higher order finite volume schemes as well as two time discretization methods: backward Euler (BE) and the second order backward differentiation formula BDF (2). It is well known that numerical (or artificial) diffusion may cause large errors. Moreover, when the Péclet number is large, a numerical code without some stabilising techniques produces oscillating solutions. Upwind schemes increase the stability but show more numerical diffusion. In this paper we quantify the numerical diffusion for the different discretization schemes and its dependency on the Péclet number. We consider an academic example and a realistic simulation of solute transport in heterogeneous aquifer. In the latter case, the stochastic estimates used as reference were obtained with global random walk (GRW) simulations, free of numerical diffusion. The results presented can be used by researchers to test their numerical schemes and stabilization techniques for simulation of contaminant transport in groundwater. 相似文献
730.
应用FLAOD实现自由场液化数值模拟试验.试验结果验证了砂土液化典型特征:超静孔隙水压升高,有效应力降低,体积压缩积累增大.证实了液化的隔振作用:砂土在液化状态变为流体,不能传递剪力,液化时砂土位移、速度、加速度振幅显著降低,剪应力降低,动水向上渗流,土体向下沉降,水平残留不可恢复位移.球压应力、有效压应力、动水压力满... 相似文献