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基于总体最小二乘-旋转不变算法的地表核磁共振信号参数估计

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电子与信息学报 2024年第2期46卷 720-727页

作者：于晓辉冯海田宝凤孙海欣孙晓东吉林大学通信工程学院长春130022 吉林大学仪器科学与电气工程学院/地球信息探测仪器教育部重点实验室长春130026 长春大学电子信息学院长春130022

在地表核磁共振(SNMR)找水系统中,根据SNMR信号的参数能够预估地下含水层的储水量、导电性以及孔隙结构等信息。然而在实际应用中探测现场采集的SNMR信号十分微弱,易受到环境噪声干扰,导致无法直接获取SNMR信号的参数。针对这一问题,该... 详细信息

在地表核磁共振(SNMR)找水系统中,根据SNMR信号的参数能够预估地下含水层的储水量、导电性以及孔隙结构等信息。然而在实际应用中探测现场采集的SNMR信号十分微弱,易受到环境噪声干扰,导致无法直接获取SNMR信号的参数。针对这一问题,该文提出基于总体最小二乘-旋转不变法(TLS-ESPRIT)的地表核磁共振信号参数估计方法。基于谐波噪声与SNMR信号的相似信号特征构成一个由多个正弦衰减信号叠加的混合信号模型,使用TLS-ESPRIT将混合信号参数提取问题转换为旋转不变矩阵的广义特征值求解,从而获得SNMR信号的拉莫尔频率和弛豫时间,并结合最小二乘法求得其初始振幅和相位。仿真信号和实测信号实验结果表明此方法能够估计出混有随机噪声和工频谐波噪声的SNMR信号的参数,相比传统的谐波建模方法,在参数提取精度上效果更好。

关键词：地表核磁共振总体最小二乘-旋转不变法谐波噪声

Refined locations of major explosions in tianjin Harbor

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Science Bulletin 2015年第21期60卷 1868-1870页

作者： Juan Li baofeng tian Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Institute of Geophysics Chinese Earthquake Administration

The Binhai New District of tianjin was shocked by two explosions in the Ruihai International Logistics warehouse in the tianjin Harbor,one of the busiest harbors of *** explosions with energy of 3 and 21 tonnes of TNT,equivalent to earthquake magnitude 2.3 and 2.9。

关键词：天津港爆炸地点 TNT炸药物流仓库滨海新区

Shear wave splitting analysis of local earthquakes from dense arrays in Shimian,Sichuan

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Earthquake Science 2023年第1期36卷 52-63页

作者： Sha Liu baofeng tian Institute of Geophysics China Earthquake AdministrationBeijing 100081China

The Shimian area of Sichuan sits at the junction of the Bayan Har ***-Yunnan rhombic block,and Yangtze block,where several faults *** region features intense tectonic activity and frequent *** this study,we used local seismic waveform data recorded using dense arrays deployed in the Shimian area to obtain the shear wave splitting parameters at 55 seismic stations and thereby determine the crustal anisotropic characteristics of the *** then analyzed the crustal stress pattern and tectonic setting and explored their relationship in the study *** some stations returned a polarization direction of NNW-SSE.a dominant polarization direction of NW-SE was obtained for the fast shear wave at most seismic stations in the study *** polarization directions of the fast shear wave were highly consistent throughout the *** orientation was in accordance with the direction of the regional principal compressive stress and parallel to the trend of the Xianshuihe and Daliangshan *** distribution of crustal anisotropy in this area was affected by the regional tectonic stress field and the fault *** mean delay time between fast and slow shear waves was 3.83 ms/*** greater than the values obtained in other regions of *** indicates that the crustal media in our study area had a high anisotropic strength and also reveals the influence of tectonic complexity resulting from the intersection of multiple faults on the strength of seismic anisotropy.

关键词： shear wave splitting polarization direction of the fast shear wave regional principal compressive stress dense array Citation:Liu S and tian BF(2023).Shear wave splitting analysis of local earthquakes from dense arrays in Shimian,Sichuan.

Shallow crustal velocity structures revealed by active source tomography and fault activities of the Mianning–Xichang segment of the Anninghe fault zone, Southwest China

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Earth and Planetary Physics 2022年第2期6卷 204-212页

作者： XiHui Shao HuaJian Yao Ying Liu HongFeng Yang baofeng tian LiHua Fang Laboratory of Seismology and Physics of Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Mengcheng National Geophysical Observatory University of Science and Technology of ChinaMengcheng Hefei 233500China CAS Center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China Earth System Science Programme Faculty of ScienceThe Chinese University of Hong KongHong Kong 999077China Shenzhen Research Institute The Chinese University of Hong KongShenzhen 518057China Institute of Geophysics China Earthquake AdministrationBeijing 100089China

The Anninghe fault is a large left-lateral strike-slip fault in southwestern China. It has controlled deposition and magmatic activities since the Proterozoic, and seismic activity occurs frequently. The Mianning-Xichang segment of the Anninghe fault is a seismic gap that has been locked by high stress. Many studies suggest that this segment has great potential for large earthquakes(magnitude >7). We obtained three vertical velocity profiles of the Anninghe fault(between Mianning and Xichang) based on the inversion of P-wave first arrival times. The travel time data were picked from seismograms generated by methane gaseous sources and recorded by three linearly distributed across-fault dense arrays. The inversion results show that the P-wave velocity structures at depths of 0-2 km corresponds well with the local lithology. The Quaternary sediments have low seismic velocities, whereas the igneous rocks,metamorphic rocks, and bedrock have high seismic velocities. We then further discuss the fault activities of the two fault branches of the Anninghe fault in the study region based on small earthquakes(magnitudes between ML 0.5 and ML 2.5) detected by the Xichang *** eastern fault branch is more active than the western branch and that the fault activities in the eastern branch are different in the northern and southern segments at the border of 28°21′N. The high-resolution models obtained are essential for future earthquake rupture simulations and hazard assessments of the Anninghe fault zone. Future studies of velocity models at greater depths may further explain the complex fault activities in the study region.

关键词： Anninghe fault zone shallow crust P-wave velocity methane gaseous source fault activity

High-resolution seismic tomography of the upper crust in the source region of the April 20,2013 Lushan earthquake and its seismotectonic implications

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Earthquake Science 2013年第3期26卷 213-221页

作者： baofeng tian Zhiwei Li Sha Liu Jiansi Yang Institute of Geophysics China Earthquake Administration State Key Laboratory of Geodesy and Earth’s Dynamics Institute of Geodesy and GeophysicsChinese Academy of Sciences

Both P- and S-wave arrivals were collected for imaging upper crustal structures in the source region of the April 20, 2013 Lushan earthquake. High-resolution, three- dimensional P and S velocity models were constructed by travel-time tomography. Moreover, more than 3700 after- shocks of the Lushan earthquake were relocated via a grid search method. The P- and S-wave velocity images of the upper crust show largely similar characters, with high and low velocity anomalies, which mark the presence of sig- nificant lateral and vertical heterogeneity at the source region of the Lushan earthquake. The characteristics of the velocity anomalies also reflect the associated surface geo- logical tectonics in this region. The distributions of high velocity anomalies of both P- and S-waves to 18 km depth are consistent with the distributions of relocated after- shocks, suggesting that most of the ruptures were localized inside the high velocity region. In contrast, low P and S velocities were found in the surrounding regions without aftershocks, especially in the region to the northeast of the Lushan earthquake. For the relocated aftershocks of the Lushan earthquake from this study, we found that mostaftershocks were concentrated in a zone of about 40 km long and 20 km wide, and were located in the hanging wall of Dayi-Mingshan fault. The focal depths of aftershocks increase from the southeast to the northwest region in the direction perpendicular to the fault strike, suggesting that the fault ruptured at an approximate dip angle of 45°. The main depths of the aftershocks in the northwest of the main shock are significantly shallower than expected, revealing the different seismogenic conditions in the source region.

关键词： Lushan earthquake Tomography Velocity structure Upper crust

融入多维度思政的“电磁场与电磁波”课程教学改革与实践

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电气电子教学学报 2024年第3期46卷 96-98页

作者：嵇艳鞠林君栾卉田宝凤周伟吉林大学仪器科学与电气工程学院长春130012

为深入贯彻落实习近平总书记关于全面推进高校课程思政建设的精神,在“电磁场与电磁波”课程教学改革中,通过设计多维度思政环节、多链条构建高阶性知识体系,多环节融合的科研案例教学模式,将知识传授与思政育人深度融合,培养学生家国... 详细信息

为深入贯彻落实习近平总书记关于全面推进高校课程思政建设的精神,在“电磁场与电磁波”课程教学改革中,通过设计多维度思政环节、多链条构建高阶性知识体系,多环节融合的科研案例教学模式,将知识传授与思政育人深度融合,培养学生家国情怀、拓展国际视野,塑造科学素养和执着的探索精神。通过合理嵌入育人要素,把思想政治工作贯穿教育教学全过程,激励学生成才,实现专业知识传授和价值引领的同频共振。

关键词：课程思政电磁场与电磁波多维度

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The characteristics of shear wave splitting in the source region of the April 20,2013 Lushan earthquake

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Earthquake Science 2013年第3期26卷 223-228页

作者： Sha Liu Jiansi Yang baofeng tian Yu Zheng Xudong Jiang Zhiqiang Xu Institute of Geophysics China Earthquake Administration

Using seismic data of the aftershocks sequence of the April 20, 2013 Lushan earthquake recorded by seismic temporary and permanent stations in the source region, with the visual inspection of particle motion diagrams, this paper preliminarily contains the polarization directions of fast shear wave and the time-delays of split shear waves at every station, and analyzes the crustal anisotropic characteristics in the source region. In the study area, the polarization direc- tions at stations BAX, TQU, L 132, L 133, L 134, and L 135 are northeast, which is consistent with the strike of Dachuan- Shuangshi fault. There are two polarization directions at MDS and L131, which are northeast and southeast. The scatter of polarization directions suggests the complex stress field around these two stations where two faults intersect. For the normalized time-delays at every station, the range is 1.02-8.64 ms/km. The largest time-delay is from L134 which is closest to the mainshock, and the smallest one is from L133. The variations in time-delays show the decreasing at stations BAX, L134, and L135 because of the stress-relaxation after earthquake.

关键词： Lushan earthquake Shear wavesplitting Polarization direction of fast shear wave Time-delay of split shear wave

Refined locations of major explosions in tianjin Harbor

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Refined locations of major explosions in Tianjin Harbor

Improved Unit Commitment with Accurate Dynamic Scenarios Clustering Based on Multi-Parametric Programming and Benders Decomposition

中国科学院地质与地球物理研究所2015年度（第15届）学术年会

作者： Juan Li baofeng tian Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Institute of Geophysics Chinese Earthquake Administration

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Energy Engineering 2024年第6期121卷 1557-1576页

作者： Zhang Zhi Haiyu Huang Wei Xiong Yijia Zhou Mingyu Yan Shaolian Xia baofeng Jiang Renbin Su Xichen tian State Grid Corporation of China Beijing100031China Central China Branch State Grid Corporation of ChinaWuhan430077China School of Electric and Electronic Engineering Huazhong University of Science and TechnologyWuhan430074China China Electric Power Research Institute Co. Ltd.Beijing100192China

Stochastic unit commitment is one of the most powerful methods to address uncertainty. However, the existingscenario clustering technique for stochastic unit commitment cannot accurately select representative scenarios,which threatens the robustness of stochastic unit commitment and hinders its application. This paper providesa stochastic unit commitment with dynamic scenario clustering based on multi-parametric programming andBenders decomposition. The stochastic unit commitment is solved via the Benders decomposition, which decouplesthe primal problem into the master problem and two types of subproblems. In the master problem, the committedgenerator is determined, while the feasibility and optimality of generator output are checked in these twosubproblems. Scenarios are dynamically clustered during the subproblem solution process through the multiparametric programming with respect to the solution of the master problem. In other words, multiple scenariosare clustered into several representative scenarios after the subproblem is solved, and the Benders cut obtainedby the representative scenario is generated for the master problem. Different from the conventional stochasticunit commitment, the proposed approach integrates scenario clustering into the Benders decomposition solutionprocess. Such a clustering approach could accurately cluster representative scenarios that have impacts on theunit commitment. The proposed method is tested on a 6-bus system and the modified IEEE 118-bus *** results illustrate the effectiveness of the proposed method in clustering scenarios. Compared withthe conventional clustering method, the proposed method can accurately select representative scenarios whilemitigating computational burden, thus guaranteeing the robustness of unit commitment.

关键词： Stochastic programming unit commitment scenarios clustering Benders decomposition multi-parametric programming