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81.
Seismic data contain random noise interference and are affected by irregular subsampling. Presently, most of the data reconstruction methods are carried out separately from noise suppression. Moreover, most data reconstruction methods are not ideal for noisy data. In this paper, we choose the multiscale and multidirectional 2D curvelet transform to perform simultaneous data reconstruction and noise suppression of 3D seismic data. We introduce the POCS algorithm, the exponentially decreasing square root threshold, and soft threshold operator to interpolate the data at each time slice. A weighing strategy was introduced to reduce the reconstructed data noise. A 3D simultaneous data reconstruction and noise suppression method based on the curvelet transform was proposed. When compared with data reconstruction followed by denoizing and the Fourier transform, the proposed method is more robust and effective. The proposed method has important implications for data acquisition in complex areas and reconstructing missing traces. 相似文献
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用B3LYP/LANL2DZ方法对ZrnPd(n =1—13)团簇的平衡几何结构、能量、频率、电子性质和磁性进行了计算.研究表明,Pd原子位于表面的异构体更为稳定,其中Zr7Pd,Zr12Pd团簇稳定性高,是幻数团簇;此外,相对于ZrnCo与ZrnFe团簇,ZrnPd团簇参与化学反应的能力较弱,化学稳定性更 相似文献
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Gang Wu Esimbek Jarken Willem Baan Jian-Jun Zhou Dong-Dong Zhou Xiao-Hong Han Aldiyar Agishev 《天文和天体物理学研究(英文版)》2018,(7)
Young protoclusters(embedded stellar clusters) are responsible for the vast majority of star formation currently occurring in the Galaxy. Recent observations suggest a scenario in which filamentary structures in the interstellar medium represent the first step towards precluster clumps and eventually star formation. Whether filaments continuously fuel the star formation process when the cluster accretes material is still an open question. In this paper, we present a case study of the famous ‘integral shaped filament'(ISF) in the Orion A molecular cloud and we seek to study the kinematics which is truly originated from the ISF. We firstly define the central ridge of the ISF with NH_3,~(12) CO,~(13) CO and N_2H~+. Undulations are present in all the ridges. Moreover, a large scale offset is apparent in the ridges as derived by different tracers, which may be explained by the slingshot mechanism proposed by Stutz Gould. We fit the velocity field of the ISF and find the derived velocity gradient is about 0.7 km s~(-1) pc~(-1) which may come from an overall contraction. We propose a method to check the accretion flow along the ISF by using the velocity deviations of different molecular tracers, which is better than the common method of using the velocity distribution of one tracer alone. Using the velocity deviations, we also find that OMC-1 to 5 are located close to the local extrema of the fluctuations, which may demonstrate that gas flows toward each clump along the ISF. 相似文献
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The dual-porosity model is usually employed to simulate the flow in fractured reservoirs. However, its original form for the multiphase flow does not consider the displacement effect under macropressure gradient. Especially for the incompressible multiphase flow, it predicts zero transfer term between fracture and matrix, which is unreasonable. To improve this, a modified double-porosity model is proposed for incompressible two-phase flow, in which the displacement effect is considered and the corresponding shape factor is derived. For the anisotropic case, the shape factor of displacement depends upon the velocity direction. The accuracy and the efficiency of the proposed dual-porosity model are indicated through numerical tests. 相似文献
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虑传播效应的多波保幅AVO正演(英文) 总被引：1，自引：1，他引：0
传统的AVO正演只考虑了单一界面的反射系数对地震波波场振幅的影响,忽略了地震波在介质中传播的各种传播效应。通过引入地震波在介质中传播的几何扩散、吸收衰减以及透射损失等传播效应,提出了基于射线理论的水平层状介质多波保幅AVO正演方法。推导了水平层状介质多波几何扩散校正公式,来描述多波在介质中传播的几何扩散效应。通过直接引入复旅行时,而无需借助复速度,建立了复旅行时与品质因子的关系,来描述粘弹介质的吸收衰减。直接求解Zoeppritz方程计算多波的透射系数,用于描述多波在介质中传播时的透射损失。数值计算表明,几何扩散、吸收衰减以及透射损失对多波振幅的影响是随偏移距变化而变化的,多波保幅AVO正演需要考虑波传播效应对反射波振幅的改造。 相似文献
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目前的瞬变电磁仪器已经为三分量瞬变电磁解释提供了硬件基础,但瞬变电磁的实用解释技术仍局限于对垂直分量的解释或一些简单近似技术。为充分利用三分量数据,进一步提高定源瞬变电磁方法的分辨率,针对定源瞬变电磁装置给出三分量全域视电阻率定义和三分量联合一维反演的方法。在进行全域视电阻率定义时,利用迭代求取反函数值的方法替代直接求取反函数的过程;引入三分量瞬变电磁数据的权重以构建联合三分量数据的目标函数,利用可行域法实现三分量联合一维瞬变电磁反演;最后将三分量解释算法分别应用在模型计算和金属矿的实际勘查资料上,以检验其有效性。模型试验和实际资料处理结果表明,三分量解释方法能够利用更多的瞬变电磁数据,获得更高分辨率的处理结果,且具有较快的计算速度。 相似文献
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加筋带布置对地基承载力的影响 总被引：2，自引：3，他引：2
现场原位载荷试验表明：素碎石薄垫层(Z/B=0.2)地基经土工带加筋后，能提高地基承载力。通过承载力比BCR分析加筋层数Ⅳ、加筋首层间距U、加筋带间距H、加筋线密度LDR对地基承载力的影响，并对极限稳定时筋带的设计拉力进行了讨论，提出用筋带的设计强度预估加筋地基极限承载力。 相似文献
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2001年11月14日昆仑山口7.8级地震、2008年3月21日于田7.1级和5月12日的汶川7.9级地震,全部发生在青藏高原中部,构成新的地震活动组.昆仑山口和汶川地震分别位于巴颜喀拉活动地块的北部和东部边界,于田地震发生在该地块的西端.GPS的观测资料分析表明该块体整体向东运动.发生在块体不同部位的昆仑山口、于田和汶川3次大地震震源机制类型体现了巴颜喀拉块体活动力学的一致性.汶川主震和强余震发生之前,出现于田序列余震的强度和频度显著增高,进一步证实同一活动地块地震之间的内在联系.2010年4月14日玉树发生6.9 级地震,连同1996年11月19日的喀喇昆仑山口6.9 级地震和1997年11月18日玛尼7.5级地震,都发生在巴颜喀拉活动地块的南部边界上,震源机制表现为一致的左旋走向滑动,证实它们属于羌塘块体向东运动的结果.事实表明活动块体具有整体运动的性质,而整体运动也是两组各自3次大地震成组活动的原因. 相似文献