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1.
Pattern search algorithms for nonlinear inversion of high-frequency Rayleigh-wave dispersion curves 总被引:1,自引:0,他引:1
Inversion of Rayleigh wave dispersion curves is challenging for most local-search methods due to its high nonlinearity and to its multimodality. In this paper, we implemented and tested a Rayleigh wave dispersion curve inversion scheme based on GPS Positive Basis 2N, a commonly used pattern search algorithm. Incorporating complete poll and complete search strategies based on GPS Positive Basis 2N into the inverse procedure greatly enhances the performance of pattern search algorithms because the two steps can effectively locate the promising areas in the solution space containing the global minima and significantly reduce the computation cost, respectively.The proposed inverse procedure was applied to nonlinear inversion of fundamental-mode Rayleigh wave dispersion curves for a near-surface shear (S)-wave velocity profile. The calculation efficiency and stability of the inversion scheme are tested on three synthetic models and a real example from a roadbed survey in Henan, China. Effects of the number of data points, the reduction of the frequency range of the considered dispersion curve, errors in P-wave velocities and density, the initial S-wave velocity profile as well as the number of layers and their thicknesses on inversion results are also investigated in the present study to further evaluate the performance of the proposed approach.Results demonstrate that pattern search algorithms applied to nonlinear inversion of high-frequency surface wave data should be considered good not only in terms of accuracy but also in terms of the computation effort due to their global and deterministic search process. 相似文献
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从银川平原空间网络生成演进入手,论述了在特定的历史地理格局下的城镇区域空间网络的演进规律.通过以自组织过程分析银川平原城镇区域空间网络的形成,得出了银川平原空间网络演进与宏观经济协调发展的关系,预测了银川平原城镇区域空间网络的未来状态,并从技术层面指出该种方法在区域规划与城市体系规划中的应用前景. 相似文献
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介绍了短时傅立叶变换、小波变换和S变换的优缺点及其彼此间的相互关系。详述了S变换的概念及性质,认为S变换方法具有良好的自适应性和时频分辨率,能提供高质量的时频谱信息。将S变换时频分析用于宜万铁路隧道地震映像法数据解释。结果表明,S变换时频剖面上的溶洞异常显示比时间剖面更为清晰,在推断岩溶的分布位置、大小、埋藏深度等方面具有良好效果。S变换方法有助于提高地震数据解释的精度和准确性。 相似文献
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Linyu Cheng Hanming Ding Changhong Chen Ningning Wang 《Journal of Materials Science: Materials in Electronics》2016,27(4):3234-3239
TiO2 nanorod arrays (TiO2 NRAs) were synthesized through a hydrothermal method. Ag2S and Bi2S3 were then grown on the surface of TiO2 NRAs with successive ionic layer adsorption and reaction method. The pristine rutile TiO2 NRAs, Ag2S/TiO2, Bi2S3/TiO2, and Bi2S3/Ag2S/TiO2 electrodes were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet–visible absorption spectroscopy, and electrochemical analysis. According to photoelectrochemical (PEC) measurement, an enhanced short circuit current density was obtained for the co-sensitized TiO2 NRAs under simulated sunlight illumination, which was 10.7 times higher than that of the TiO2 NRAs. Appropriate potential positions of conduction band and valence band of Bi2S3 that match well those of rutile TiO2 NARs and Ag2S lead to the improved PEC performance. In addition, the PEC property of the co-sensitized TiO2 NRAs under visible light irradiation was also investigated and showed a dramatically enhanced photocurrent response. 相似文献
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近段时间来,社会主义新农村建设正在全国各地如火如荼地展开着,如何在村庄建设规划中进行社会主义新农村建设,如何将规划理念落实在实处,该文结合湖南长沙县石塘铺村村庄规划实例,进行一些探讨性的论述,希望能起抛砖引玉之作用. 相似文献