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The seismogenic structure of strong intraplate earthquakes in Shantou region, South China: Insights from upper crustal shear-wave velocity structure

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Earthquake Research Advances 2025年

作者： Lue Yang Lun Li Xiuwei Ye Jinming Zhang Jialong He Yuan Gao Pengfei Li Yu He Ziwei Li School of Earth Sciences and Engineering Sun Yat-Sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) 519082 China China Earthquake Administration Key Laboratory of Earthquake Monitoring and Disaster Mitigation Technology Guangdong Earthquake Agency Guangzhou 510070 China Guangdong Science and Technology Collaborative Innovation Center for Earthquake Prevention and Disaster Mitigation Guangzhou 510070 China Key Laboratory of Disaster Forecast and Control in Engineering of the Ministry of Education Urban Earthquake Safety Laboratory Guangzhou 510070 China

The Shantou region, one of the most seismically active zones of Guangdong Province (South China), has experienced multiple strong earthquakes including two significant events with magnitudes greater than 7.0 occurred in 1600 and 1918, respectively. To investigate the seismogenic structures responsible for these major earthquakes and their potential triggering mechanisms, in this study, we construct a high-resolution shear-wave velocity model from surface to ∼15 km depth based on a dense nodal seismic array using ambient noise tomography. The model reveals a pronounced low-velocity zone (LVZ) at depths of 2-15 km, with a perturbation of -2 to -8%, coinciding with the northwestern extension of the Huanggangshui Fault previously identified in the offshore region. Integrating our results with previous field geological surveys and shallow reflection seismic exploration, we interpret the LVZ as a wide fault zone, potentially comprising multiple fault branches that possibly includes two NW-trending faults (i.e., the Rongjiang Fault and the Hanjiang Fault). Notably, the interaction between the Huanggangshui Fault and NE-trending Littoral Fault is suggested to have triggered the 1918 M7.3 Nan’ao earthquake. Additionally, the 1895 M6.2 earthquake seems to occur at the edge of the LVZ near the Rongjiang Fault, a possible branch of the Huanggangshui Fault, further supporting the association between this structure and seismic activity. These findings imply that the LVZ may represent a region of concentrated tectonic stress, making it a potential site for future strong earthquakes. Consequently, this area should be prioritized in seismic hazard assessments. This study provides valuable insights into the seismogenic characteristics of the Shantou region and contributes to improving seismic hazard evaluations in South China.

关键词： Intraplate earthquakes Nan’ao earthquake Shear-wave velocity Ambient noise tomography Dense seismic array

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A novel preconditioned range restricted GMRES algorithm for moving force identification and its experimental validation

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MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2021年 155卷

作者： Chen, Zhen Qin, Lifeng Chan, Tommy H. T. Yu, Ling North China Univ Water Resources & Elect Power Sch Civil Engn & Commun Zhengzhou 450045 Peoples R China Queensland Univ Technol QUT Sch Civil & Environm Engn Brisbane Qld 4000 Australia Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

Moving force identification (MFI) is a widely concerned inverse problem in structural dynamics and well-known as intrinsically existing ill-posedness. With the help of Arnoldi process and Krylov subspace method, the generalized minimal residual (GMRES) method can be improved to a range restricted generalized minimal residual (RRGMRES) method. Furthermore, by introducing the smoothing-norm preconditioning, a preconditioned range restricted generalized minimal residual (PRRGMRES) method is proposed to provide a stable solution to the ill-posed dynamic force identification problem. Simulations show that the novel method has significant improvement when compared to the classic time domain method and the RRGMRES method. In addition, to show the effectiveness and advantages of the proposed method, the PRRGMRES method is also compared with a newly-proposed regularization method named the preconditioned least square QR-factorization (PLSQR) method. Simulation results show that the PRRGMRES method has much better robustness and higher computational efficiency than the PLSQR method especially in dealing with highly inaccurate measurement cases. Finally, the accuracy and efficiency of the PRRGMRES method is verified by experimental studies. The PRRGMRES method has good performance in both overcoming ill-posed problems and improving computational efficiency, which should be of the highest priority in adoption for MFI. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Moving force identification Preconditioned range restricted generalized minimal residual method Preconditioned least square QR-factorization method Smoothing-norm preconditioning Ill-posed problem

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Sparse regularization-based damage detection in a bridge subjected to unknown moving forces

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JOURNAL OF CIVIL STRUCTURAL HEALTH MONITORING 2019年第3期9卷 425-438页

作者： Pan, Chudong Yu, Ling Guangzhou Univ Sch Civil Engn Guangzhou 510006 Guangdong Peoples R China Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

Output-only structural damage detection (SDD) is an important issue in the field of structural health monitoring (SHM). As an attempt, this study aims to propose a sparse regularization-based method for detecting the structural damage using structural responses caused by unknown moving forces. First, a transmissibility matrix between two sensor sets is constructed using a known bridge model and least square-based moving force identification algorithm. Second, the measured responses are used as inputs to estimate the reconstructed responses with the help of the transmissibility matrix. Then, the damage detection procedure can be regarded as an optimization problem trying to find a possible damage vector, which makes the difference between the measured and reconstructed responses minimum. L-p-norm (0 < p <= 1) sparse regularization is adopted to improve the ill-conditioned SDD problem. To assess the feasibility of the proposed method, damaged bridges subjected to moving forces are taken as examples for numerical simulations. Differences between finite element model (FEM) used for model updating and the one applied to simulate the true damage conditions are considered. The illustrated results show that the proposed method can identify structural damages with a strong robustness. Some related issues, such as regularization parameters, finite element models, L-p-norm (0 < p <= 1) penalty terms, noise levels and damage patterns, are discussed as well.

关键词： Structural health monitoring (SHM) Structural damage detection (SDD) Sparse regularization Unknown moving force

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STUDY ON THE PROPERTIES OF POLYURETHANE-CEMENT COMPOSITE (PUC)

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CIVIL engineering JOURNAL-STAVEBNI OBZOR 2021年第2期30卷 560-571页

作者： Zhang, Kexin Li, Dachao Qi, Tianyu Li, Yanfeng Xue, Xingwei Jinan Univ MOE Key Lab Disaster Forecast & Control Engn 601 Huangpu Dadao West Guangzhou Peoples R China Shenyang Jianzhu Univ Sch Traff Engn 25 Hunnan Zhong Rd Shenyang Liaoning Peoples R China

In order to study the properties of polyurethane cement composite (PUC) material, this paper has carried out the tests of compressive resistance, flexural resistance, axial tension, bonding and acid and alkali corrosion resistance of the material. The average compressive strength of the material is 59.3 MPa, the average flexural strength is 41.5 MPa, and the average axial tensile strength is 31.0 MPa. The bonding strength between the material and concrete in axial tension is 3.56 MPa, and that between the material and concrete in bending is 3.16 MPa. The failure interface of the two bond tests is not on the bond surface, indicating that the polyurethane cement composite (PUC) material has good bonding property. The chemical corrosion resistance test of polyurethane cement material showed no visible change on the surface of the material, indicating good chemical corrosion resistance.

关键词： Polyurethane cement Mechanical property Acid and alkali resistance Adhesive property

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Lidar- and UAV-Based Vertical Observation of Spring Ozone and Particulate Matter in Nanjing, China

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REMOTE SENSING 2022年第13期14卷

作者： Qu, Yawei Zhao, Ming Wang, Tijian Li, Shu Li, Mengmeng Xie, Min Zhuang, Bingliang Jinling Inst Technol Coll Intelligent Sci & Control Engn Nanjing 211169 Peoples R China Nanjing Univ Informat Sci & Technol Minist Educ Key Lab Meteorol Disaster KLME Nanjing 210044 Peoples R China Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteoro Nanjing 210044 Peoples R China Chinese Acad Sci Anhui Inst Opt & Fine Mech Hefei Inst Phys Sci Key Lab Atmospher Opt Hefei 230031 Peoples R China Nanjing Univ Sch Atmospher Sci Nanjing 210023 Peoples R China

The rapid urbanization in China is accompanied by increasingly serious air pollution. Particulate matter and ozone are the main air pollutants, and the study of their vertical distribution and correlation plays an important role in the synergistic air pollution control. In this study, we performed Lidar- and UAV-based observations in spring in Nanjing, China. The average concentrations of surface ozone and PM2.5 during the observation period are 87.78 mu g m(-3) and 43.48 mu g m(-3), respectively. Vertically, ozone reaches a maximum in the upper boundary layer, while the aerosol extinction coefficient decreases with height. Generally, ozone and aerosol are negatively correlated below 650 m. The correlation coefficient increases with altitude and reaches a maximum of 0.379 at 1875 m. Within the boundary layer, ozone and aerosols are negatively correlated on days with particulate pollution (PM2.5 > 35 mu g m(-3)), while on clean days they are positively correlated. Above the boundary layer, the correlation coefficient is usually positive, regardless of the presence of particulate pollution. The UAV study compensates for Lidar detections below 500 m. We found that ozone concentration is higher in the upper layers than in the near-surface layers, and that ozone depletion is faster in the near-surface layers after sunset.

关键词： particulate matter ozone Lidar UAV

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The mechanical mechanism and plastic hinge behavior of novel precast prestressed steel reinforced concrete composite frames with PVA fiber-reinforced ECC cast-in-place joints subjected to monotonic load

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Structures 2025年 79卷

作者： Jing Ji Xuan Chu Liangqin Jiang Zhanbin Zhang Xiaomeng Hou Pengguang Qi Heilongjiang Key Lab of Disaster Prevention Mitigation and Protection Engineering Northeast Petroleum University Daqing 163319 China Heilongjiang Provincial Key Laboratory of Thermal Utilization and Disaster Reduction of New Energy in Cold Regions Northeast Petroleum University Daqing 163319 China Key Laboratory of Structural Disaster and Control of the Ministry of Education Harbin Institute of Technology Harbin 150040 China

In this paper, a novel type of precast prestressed steel reinforced concrete composite frames with PVA fiber-reinforced engineering cementitious composites (PVA-ECC) cast-in-place joints (PSCEFs) is systematically proposed. It consists of precast prestressed steel reinforced concrete beams (PSRCBs), precast small-diameter concrete-filled steel tube gradient strength composite columns (SGCCs), and PVA-ECC cast-in-place joints. To investigate the stress mechanism of the PSCEFs under monotonic loading, refined three-dimensional finite element models of 15 PSCEFs and 2 precast prestressed steel reinforced concrete composite frames with ordinary concrete cast-in-place joints (PSCCFs) are established based on the nonlinear constitutive models of several materials and the geometric nonlinearity of structures. The rationality of the modeling method is well verified by referring to existing tests. The effects of different parameters on the ultimate bearing capacity, ductility, and initial stiffness for PSCEFs are studied, and the results indicate that the stirrup characteristic value ( λ v ) and axial compression ratio ( n ) of SGCCs have a remarkable impact on the ultimate bearing capacity of PSCEFs. The displacement ductility coefficients of PSCEFs are mainly above 4.0, and the initial stiffness is about 15 % higher than that of PSCCFs, so PSCEFs have better ductility and suitable deformation resistance. By comparing the collapse resistance and failure modes for typical specimens of PSCEFs and PSCCFs, it is discovered that the joints poured with PVA-ECC can effectively control the range of plastic strain distribution in the frames. The yield lengths of shaped steel, steel reinforcement, and concrete in PSCEFs are reduced by approximately 5–20 % compared to those of PSCCFs. The failure characteristics and plastic hinges law of PSCEFs are systematically summarized, and the plastic hinge length prediction models with an error of less than 10 % are proposed by introducing seve

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Screws Fixation for Oblique Lateral Lumbar Interbody Fusion (OL-LIF): A Finite Element Study

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BIOMED RESEARCH INTERNATIONAL 2021年第1期2021卷 5542595页

作者： Ling, Qinjie Zhang, Huanliang He, Erxing Guangzhou Med Univ Dept Spinal Surg Affiliated Hosp 1 151 Yanjiang West Rd Guangzhou 510120 Guangdong Peoples R China Jinan Univ Inst Appl Mech MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

Background. The combination of screw fixation and cage can provide stability in lumbar interbody fusion (LIF), which is an important technique to treat lumbar degeneration diseases. As the narrow surface cage is developed in oblique lateral lumbar interbody fusion (OL-LIF), screw fixation should be improved at the same time. We used the finite element (FE) method to investigate the biomechanics response by three different ways of screw fixation in OL-LIF. Methods. Using a validated FE model, OL-LIF with 3 different screw fixations was simulated, including percutaneous transverterbral screw (PTVS) fixation, percutaneous cortical bone trajectory screw (PCBTS) fixation, and percutaneous transpedical screw (PPS) fixation. Range of motion (ROM), vertebral body displacement, cage displacement, cage stress, cortical bone stress, and screw stress were compared. Results. ROM in FE models significantly decreased by 84-89% in flexion, 91-93% in extension, 78-89% in right and left lateral bending, and 73-82% in right and left axial rotation compared to the original model. The maximum displacement of the vertebral body and the cage in six motions except for the extension of model PTVS was the smallest among models. Meanwhile, the model PTVS had the higher stress of screw-rods system and also the lowest stress of cage. In all moments, the maximum stresses of the cages were lower than their yield stress. Conclusions. Three screw fixations can highly restrict the surgical functional spinal unit (FSU). PTVS provided the better stability than the other two screw fixations. It may be a good choice for OL-LIF.

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Aqueous Ammonia With Sodium Sulfite Pretreatment For Enhancing Enzymatic Saccharification and Bioethanol Production of Sugarcane Bagasse

Research Square

引用

Research Square 2021年

作者： Zeng, Minxia Tang, Baoying Li, Peijin Liang, Zhiquan Li, Xiaozhen Wang, Jue Lin, Jianghai Xiao, Wenjuan Xu, Yuan Huang, Shiqing Liu, Zehuan Research Center for Molecular Biology Institute of Life and Health Engineering College of Life Science and Technology Jinan University Guangzhou510632 China MOE Key Laboratory of Disaster Forecast and Control in Engineering School of Mechanics and Construction Engineering Jinan University Guangzhou510632 China Guangzhou Institute of Low-carbon Biotechnology China

Background: Bioethanol is considered as a promising alternative fuel. Lignocellulosic biomass can be used for the production of bioethanol, but its recalcitrant structure makes it difficult to be utilized. Thus, proper pretreatment is a crucial step to break this structure and enhance enzymatic saccharification. Aqueous ammonia with sodium sulfite pretreatment (AAWSSP) was first applied to enhance the enzymatic saccharification and bioethanol production of sugarcane bagasse (SCB) in this research. Results: Response surface methodology was applied to optimize the conditions of pretreatment. Under optimal parameters, 16.92 g/L of total sugar concentration (P1 SCB: 202.08℃, 11.06% aqueous ammonia, 13.37% sodium sulfite, 1.22 h) and 0.51 g/g of total sugar yield (P2 SCB: 199.47℃, 10.17% aqueous ammonia, 13.11% sodium sulfite, 1.17 h) were achieved, respectively. The results of ethanol fermentation showed that separate hydrolysis and fermentation performed better than that of simultaneous saccharification and fermentation, and the maximum ethanol yields of 143.30 g/kg for P1 SCB and 145.33 g/kg for P2 SCB, were obtained, respectively. Conclusions: This research indicated that aqueous ammonia and sodium sulfite in pretreatment solution might have a synergistic effect on delignification and enzymatic saccharification. AAWSSP might be a prospective method for enhancing enzymatic saccharification and bioethanol production of SCB, which provided new guidance for the bio-refinery of lignocellulose. © 2021, CC BY.

关键词： Ethanol

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Three-body problem – from Newton to supercomputer plus machine learning

arXiv

引用

arXiv 2021年

作者： Liao, Shijun Li, Xiaoming Yang, Yu State Key Lab of Ocean Engineering Shanghai200240 China Center of Marine Numerical Experiment School of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University Shanghai200240 China School of Physics and Astronomy Shanghai Jiaotong University Shanghai200240 China School of Mechanics and Construction Engineering Jinan University Guangzhou510632 China MOE Key Laboratory of Disaster Forecast and Control in Engineering Guangzhou510632 China

The famous three-body problem can be traced back to Newton in 1687, but quite few families of periodic orbits were found in 300 years thereafter. In this paper, we propose an effective approach and roadmap to numerically gain planar periodic orbits of three-body systems with arbitrary masses by means of machine learning based on an artificial neural network (ANN) model. Given any a known periodic orbit as a starting point, this approach can provide more and more periodic orbits (of the same family name) with variable masses, while the mass domain having periodic orbits becomes larger and larger, and the ANN model becomes wiser and wiser. Finally we have an ANN model trained by means of all obtained periodic orbits of the same family, which provides a convenient way to give accurate enough predictions of periodic orbits with arbitrary masses for physicists and astronomers. It suggests that the high-performance computer and artificial intelligence (including machine learning) should be the key to gain periodic orbits of the famous three-body problem. © 2021, CC BY.

关键词： Supercomputers

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Effect of viscoelasticity on interfacial stress transfer mechanism in the biocomposites: A theoretical study of viscoelastic shear lag model

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COMPOSITES PART B-engineering 2019年 164卷 297-308页

作者： Wu, Jiayu Yuan, Hong Li, Long-yuan Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Inst Appl Mech Guangzhou 510632 Guangdong Peoples R China Univ Plymouth Sch Engn Plymouth PL4 8AA Devon England

Biocomposite with regularly staggered alignment microstructure is frequently observed in natural biological tissues, and exhibits superior mechanical behavior. Owing to their viscoelastic nature, biocomposites exhibit stress rate-dependent stiffness function and mechanical behavior. In this paper, a linear viscoelastic shear lag model (SLM) is proposed to illustrate the micromechanical behavior of biocomposites under triangular loading pulse. Theoretical and numerical results are derived to predict the deformation and stress transfer between fibers and interfibrous matrix while the biocomposite is transiently stretched. The results from the analytical and numerical solutions demonstrate that how the fiber overlap length and loading rate affect the stress transfer and mechanical properties of biocomposites. The structure-property correlation is illustrated for viscoelastic biomaterials under transient loading, and existence of characteristic length of soft matter with viscoelastic property is involved in load transfer mechanism between the adjacent reinforcements in transient regime, which optimizes the load transfer mechanism between the adjacent reinforcements. Furthermore, we found that discontinuous fibril model could ensure large relative sliding deformation, helping dissipate energy, protecting fibril from overall damage, and achieving high ductility and high toughness, which can provide beneficial design strategies for engineering fiber reinforced composites.

关键词： Biocomposites Shear lag model Mechanics of composite interface Viscoelastic model Mechanical response

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