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161.
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Chunyan Zhang Sidao Ni Key Lab of Intelligent Computing Signal Processing of Ministry of Education School of Mathematics Anhui University Hefei China Key Laboratory of Dynamic Geodesy 《地震学报(英文版)》2011,(1):127-132
We analyzed the seismic waveforms from the December 26,2004 Sumatra-Andaman earthquake recorded at broadband seismic stations in western Europe.Previous studies involving of the beam-forming technique and high frequency analysis suggest that the earthquake ruptured with a duration of around 500 s.This very long duration makes P wave overlap with later arrivals such as PP wave,which follows P in about 200 s.Since P waves are crucial for modeling earthquake processes,we propose an iterative method to separate... 相似文献
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我国著名大型锡矿大厂矿区的100号矿体是一个不规则的大脉状矿体,由质密锡铅锌矿石组成。该大脉矿体长度约1200多米。大厂矿区矿床形成过程有两个主要矿化阶段:早期锡石硫化物阶段和晚期的硫盐锡石多金属矿化阶段。矿物流体包体数据表明:早期形成于300~400℃(450℃)条件下,有高盐度流体包体与低盐度流体包体共存,流体处于从超临界流体进入近临界的气液两相不混溶区过渡阶段,有流体沸腾现象;晚期流体盐度变化小处于降温过程。而100号矿体形成于300~360℃,压力较低,仅为8.24MPa。本次研究设计一含锡溶液从超临界态进入亚临界态的气液不混溶区的实验,研究金属在气-液间再分配过程。实验模拟一个非平衡的气液分离反应动力学过程。重点研究含Sn-NaHCO3-HCl-H2O在近临界压(25~22MPa)和8~14MPa、380~300℃条件下,在亚临界态气-液两相不混溶区时相分离过程。气液分离实验是恒压降温过程。结果表明:近临界区NaHCO3-HCl-H2O的NaCl-H2O体系出现气-液(L-V)分离现象。降温远离临界点时,在V与L相里的Na、Cl浓度比:Na(V/L)、Cl(V/L)比值多数远小于1,Na、Cl主要分布在液相里。实验表明出现含Sn溶液的V-L两相分离过程,并且,Sn已在L-V间再分配,Sn(V/L)多数大于1。说明Sn多数情况下分布于气相里(贫NaCl富H2OCO2)。在380~250℃范围内NaCl-H2O-CO2体系包含的H2O-CO2体系也出现V-L两相不混溶区。实验发现H2O-CO2的L-V分离过程中,气相里HCO-3和CO2-3分布很少,CO2多。同时,锡在H2O-CO2的L-V间也存在再分配,锡分布在富CO2气体里。实验说明富CO2气体迁移锡。实验为地质解释提供依据,说明100号矿体形成于快速减压的大型裂隙条件下。在300~360℃下压力减低,使含金属流体迅速进入L-V两相不混溶区,气体快速迁移金属,快速沉积金属矿石。 相似文献
167.
青海盐湖卤水锂资源储量丰富,高镁锂比卤水存在镁锂分离难的问题。基于非平衡动态降温过程中不同盐组分结晶行为存在差异的原理,开展了强制分离高镁锂比卤水的研究,考察了卤水镁锂比、降温速率、流体状态和卤水温度对镁锂分离效果的影响,并分析了结晶过程中镁锂分离的介稳性特点。结果表明,通过非平衡动态降温结晶析出MgCl2·6H2O,可以实现卤水脱镁和镁锂分离,当降温速率为-1.25℃/min、卤水温度在70℃至50℃范围内,镁锂比在10∶1~80∶1时,镁锂分离因子最高可达到1.876,结晶的MgCl2·6H2O纯度最高为99.42%。非平衡动态降温结晶工艺相较于经典的盐田工艺,最多可将锂损失率从模拟盐田工艺的38.39%降至7.56%。该工艺为盐湖卤水镁锂分离提供了一条新的思路,也为后续高纯锂盐的制备奠定了基础。 相似文献
168.
Yinhe Luo Jianghai Xia Yixian Xu Chong Zeng Richard D. Miller Qingsheng Liu 《Pure and Applied Geophysics》2009,166(3):353-374
Multichannel analysis of surface waves (MASW) method is a non-invasive geophysical technique that uses the dispersive characteristic
of Rayleigh waves to estimate a vertical shear (S)-wave velocity profile. A pseudo-2D S-wave velocity section is constructed
by aligning 1D S-wave velocity profiles at the midpoint of each receiver spread that are contoured using a spatial interpolation
scheme. The horizontal resolution of the section is therefore most influenced by the receiver spread length and the source
interval. Based on the assumption that a dipping-layer model can be regarded as stepped flat layers, high-resolution linear
Radon transform (LRT) has been proposed to image Rayleigh-wave dispersive energy and separate modes of Rayleigh waves from
a multichannel record. With the mode-separation technique, therefore, a dispersion curve that possesses satisfactory accuracy
can be calculated using a pair of consecutive traces within a mode-separated shot gather. In this study, using synthetic models
containing a dipping layer with a slope of 5, 10, 15, 20, or 30 degrees and a real-world example, we assess the ability of
using high-resolution LRT to image and separate fundamental-mode Rayleigh waves from raw surface-wave data and accuracy of
dispersion curves generated by a pair of consecutive traces within a mode-separated shot gather. Results of synthetic and
real-world examples demonstrate that a dipping interface with a slope smaller than 15 degrees can be successfully mapped by
separated fundamental waves using high-resolution LRT. 相似文献
169.
An experimental investigation of the airflow structure in the near surface region over the wind-sheared air–water interface
is reported. The two-dimensional velocity fields in a plane perpendicular to the water surface were measured using particle
image velocimetry (PIV) technique over a wind speed range from 1.5 to 4.4 m s−1. The results show a reduction in the mean velocity magnitudes and the tangential stresses when gravity waves appear on the
surface. An enhanced vorticity layer was observed immediately above the water surface that extended to a height of approximately
2 cm. The vorticity was enhanced by an order of magnitude, and the energy dissipation rate was enhanced by a factor of 7 in
this layer at all wind speeds. The vertical profiles of Reynolds stress, energy production, and dissipation indicate the contribution
of surface waves in the enhanced transfer of momentum and energy between the two fluids. The results in this study show that
the flow dynamics in a layer immediately adjacent to the water surface whose thickness is of the order of the significant
wave height is significantly different from that at greater heights. Thus, it is concluded that the quantitative investigation
of the flow in the immediate vicinity of the interface is vital for an improved understanding of the heat, mass, and momentum
exchange between air and water. The present study demonstrates that PIV is an effective technique to accurately measure the
velocity fields in this region. 相似文献
170.
泥质烃源岩密度分级分离与有机碳分配 总被引:4,自引:0,他引:4
选取东营凹陷第三系11 块泥质烃源岩样品,粉碎后按小于1.6 g/cm3,1.6~2.2 g/cm3 和大于2.2 g/cm3 的密度,分离成1,2,3 三个组分,希望可以把烃源岩中游离的有机质、无机矿物与有机黏土复合体分别提取出来。对各组分进行质量、有机碳及扫描电镜分析,探讨不同密度组分中有机质赋存形式及有机碳分配方式的差异性。密度分组后各组分的质量、有机碳量回收率基本上达到100%,表明密度分离方法可信,且对烃源岩的破坏较弱。通过扫描电镜观察发现,1 组分中存在大量的生物碎屑有机质,经盐酸处理后,有机质颗粒表面干净,而2,3 组分中只见有大量的矿物颗粒,但能谱分析显示了C 元素的存在。这些特征表明1 组分为生物碎屑有机质,而2,3 组分中有机质与无机矿物相混合。有机碳分析表明,1 组分有机碳含量平均高达14.24%,但其仅占全岩有机碳量的1.11%;2,3 组分中有机碳含量分别为3.26%,2.77%,两者占全岩有机碳量的90% 以上。由此看来与无机矿物相结合是烃源岩中有机质较为重要的赋存方式,这部分有机质对全岩生烃量的贡献不容忽视。 相似文献