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111.
On 5 April 2008, a filament at the periphery of an active region was observed by the Extreme Ultraviolet Imager telescope aboard the STEREO-A spacecraft, which showed up as a prominence eruption in the field-of-view from STEREO-B. The filament at STEREO-A 304 Å was first lengthened toward a region with weak overlying magnetic field so evolved as a large-scale one consisting of bright and dark threads twisting with each other, and then the portion below the weak field underwent an eruption. Meanwhile, the corresponding STEREO-B 304 Å prominence threads exhibited a kinking structure and tilting motion, with its center deflecting from the radial direction. By using three-dimension (3D) reconstruction technology, we obtain the 3D topology for the kinked prominence when its apex arrived at 1.4 radii, from which a clockwise rotation of about 90° is found in the course of the eruption. By comparing the 3D structure with the magnetic-field configuration computed by using the Potential-Field Source-Surface (PFSS) model, it is suggested that the filament erupted against the rather weaker than stronger overlying magnetic field, which make it appear to tilt toward one side. 相似文献
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含Ti硅酸盐玻璃在基础科学研究和应用技术开发上均有重要价值,亟需对其进行准确的成分分析,为进一步的科研工作提供重要的数据支撑.对玻璃进行电子探针分析时,由于样品的易损性和其中(Na和K)阳离子在电子束轰击下极易发生迁移和扩散,因此往往需要经过条件实验来确定合适的分析条件,确保样品在该条件下能够保持尽量稳定的状态,才能获... 相似文献
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Yan Shuang Xian-Wu Bi Rui-Zhong Hu Jian-Tang Peng Hang Li Da-Hua Li Chang-Sheng Zhu 《Resource Geology》2010,60(1):18-34
The Furong tin deposit in the central Nanling region, South China, consists of three main types of mineralization ores, i.e. skarn-, altered granite- and greisen-type ores, hosted in Carboniferous and Permian strata and Mesozoic granitic intrusions. Calcite is the dominant gangue mineral intergrown with ore bodies in the orefield. We have carried out REE, Mn, Fe, and Mg geochemical and C, and O isotopic studies on calcites to constrain the source and evolution of the ore-forming fluids. The calcites from the Furong deposit exhibit middle negative Eu anomaly (Eu/Eu*= 0.311–0.921), except for one which has an Eu/Eu* of 1.10, with the total REE content of 5.49–133 ppm. The results show that the calcites are characterized by two types of REE distribution patterns: a LREE-enriched pattern and a flat REE pattern. The LREE-enriched pattern of calcites accompanying greisen-type ore and skarn-type ore are similar to those of Qitianling granite. The REE, Mn, Fe, and Mg abundances of calcites exhibit a decreasing tendency from granite rock mass to wall rock, i.e. these abundances of calcites associated with altered granite-type and greisen-type ores are higher than those associated with skarn-type ores. The calcites from primary ores in the Furong deposit show large variation in carbon and oxygen isotopic compositions. The δ13C and δ18O of calcites are −0.4 to −12.7‰ and 2.8 to 16.4‰, respectively, and mainly fall within the range between mantle or magmatic carbon and marine carbonate. The calcites from greisen and altered granite ores in the Furong deposit display a negative correlation in the diagram of δ13C versus δ18O, probably owing to the CO2-degassing of the ore-forming fluids. From the intrusion to wall-rock, the calcites display an increasing tendency with respect to δ13C values. This implies that the carbon isotopic compositions of the ore-bearing fluids have progressively changed from domination by magmatic carbon to sedimentary carbonate carbon. In combination with other geological and geochemical data, we suggest that the ore-forming fluids represent magmatic origin. We believe that the fluids exsolved from fractionation of the granitic magma, accompanying magmatism of the Qitianling granite complex, were involved in the mineralization of the Furong tin polymetallic deposit. 相似文献
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The dispersion characteristics of shallow water can be described by the dispersion curves, which contain substantial ocean parameter information. A fast ocean parameter inversion method based on dispersion curves with a single hydrophone is presented in this paper. The method is achieved through Bayesian theory. Several sets of dispersion curves extracted from measured data are used as the input function. The inversion is performed by matching a replica calculated with a dispersion formula. The bottom characteristics can be described by the bottom reflection phase shift parameter P. The propagation range and the depth can be inverted quickly when the seabed parameters are represented by on parameter P. The inversion results improve the inversion efficiency of the seabed parameters. Consequently, the inversion efficiency and accuracy are improved while the number of inversion parameters is decreased and the computational speed of replica is increased. The inversion results have lower error than the reference values, and the dispersion curves calculated with inversion parameters are also in good agreement with extracted curves from measured data; thus, the effectiveness of the inversion method is demonstrated. 相似文献
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以大黄鱼(Larimichthys crocea)为研究对象,研究急性、慢性低盐度胁迫对大黄鱼存活状况及非特异性免疫酶活力的影响。结果表明:急性低盐(15、8)胁迫下,在7 d的实验周期中,大黄鱼肝脏的超氧化物歧化酶(superoxide dismutase, SOD)活力呈先上升后下降的趋势,在第1天显著上升(p<0.05)后逐渐下降至显著低于对照组水平;肝脏的过氧化氢酶(catalase, CAT)活力整体呈先下降后上升再下降的趋势,在第1天显著下降后开始升高,第3天后开始下降,至第7天时CAT活力仍显著低于对照组水平;血清中的酸性磷酸酶(acid phosphatase, ACP)活力呈下降后逐渐升高的趋势,在第1 天时显著下降后逐步升高,至第7天时仍显著低于对照组;而血清中的碱性磷酸酶(alkaline phosphatase, ALP)活力在实验开始的第1天到第3天逐渐升高,且均显著高于对照组,至第7天时开始下降至对照组水平;血清中的溶菌酶(lysozyme, LZM)含量呈波动变化,整体呈先上升后下降趋势。慢性低盐(8)养殖14 d后,大黄鱼的各项非特异性免疫酶活力均与对照组无显著性差异(p>0.05)。此外,实验周期内所有组别大黄鱼均未出现死亡,仅急性低盐胁迫组大黄鱼的活动和摄食受到有限影响。大黄鱼对慢性降盐度养殖有较高的耐受能力,而盐度骤降会显著影响大黄鱼的非特异性免疫,实际生产中应避免养殖环境盐度的剧烈变化。 相似文献
120.
Improvement of pseudo-static method for slope stability analysis 总被引:2,自引:0,他引:2
traditional In this paper, two drawbacks pseudo-static method (vertical of the slice method) in the slope stability evaluation have been studied. First, the sliding mass is divided into vertical slices according to this method, which is irrational to some extent in the seismic design of slope. Second, only peak ground acceleration (PGA) is considered, and the effects of shaking frequency and duration on slope stability are neglected. And then, based on the theory of elastic wave and the summarized geological model, this paper put forwards an improved method of pseudo-method by using the theory of elastic wave and Hilbert-Huang transform. The improved pseudostatic method gives reasonable considerations to the time-frequency effects of seismic wave and its rationality has been verified by the shaking table test. This method can evaluate the safety of a slope, the happening time and the scale of landslides. At the same time, this method also can improve the high accuracy of the evaluation of the safety of the slope. 相似文献